UV FLUX measurement and control system

Abstract

A method, system, and apparatus useful for measuring and regulating UV irradiation of a space furnished with a UV radiation source. The UV radiation can be UV radiation. The system involves determining an amount of ozone in air in the space concomitantly with operating the UV radiation source, and evaluating the determined ozone amount against one or more ozone concentration reference values to obtain a proxy measurement for UV irradiation in the space. The proxy measurement can be used to adjust or regulate radiation output from the UV radiation source. The disclosure also provides a method, system, and apparatus useful for calibrating and testing the UV radiation source, and a method, system, and apparatus useful for germicidal UV treatment of a space.

Description

UV FLUX MEASUREMENT AND CONTROL SYSTEM CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63 / 588,676, filed Oct 6, 2023, the disclosure of which is incorporated herein in its entirety by reference. TECHNICAL FIELD

[0002] This document pertains generally to UV systems for inactivating pathogens. The present application also relates, but not by way of limitation, to a system useful providing far-UV light. BACKGROUND

[0003] Germicidal irradiation with UV light is useful for removing infection agents in a wide range of settings, and has found particular use in hospital and other higher risk environments. However, certain wavelengths of UV light can be harmful to humans. Advances in the field of far-UV light, particularly 222 nm light, have demonstrated potential to provide effective germicidal properties while ensuring the safety of human occupants. When delivered at suitable levels, far- UV light has the ability to inactivate pathogens without harming human tissue. Due to this unique characteristic, far-UV light has attracted considerable interest as it presents a valuable solution for safe disinfection in various settings, such as schools, hospitals, offices, and public spaces. However, it is important that the technology is safely and responsibly implemented. The ACGIH (American Conference of Governmental Industrial Hygienists) has set a Threshold Limit Values for the amount of 222nm Far UV exposure. Moreover, UV radiation can generate undesirable contaminants in air, including ozone (O3). At excessive concentrations, O3 has the potential to cause acute and chronic health effects and can significantly degrade indoor air quality through oxidation chemistry. See, e.g., Poppendieck et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 675^679; Jimenez et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 668^674; and Barber et al., ChemRxiv. Jul. 18, 2023.

[0004] New developments are needed to safely manage the dangers of airborne pathogens and improve systems for use with UV light. SUMMARY

[0005] The disclosure provides a method, system, and apparatus for assessing UV irradiation of air treated with a germicidal UV radiation source by utilizing ozone amount as a proxy measurement for UV irradiation. The disclosure provides a method of assessing UV radiation in a space having one or more UV radiation sources, comprising determining an amount of ozone in air of the space while irradiating the air with the UV radiation source; and processing the determined ozone amount to obtain a proxy measurement for UV irradiation in the space. In various aspects, ozone can be determined by measurement with an ozone detector or it can be determining indirectly by use of a calibration value as described herein. The UV radiation source can be a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm. In various aspects, the UV radiation source can be a far-UV radiation source that emits radiation comprising one or more wavelengths of about 210 nm to about 230 nm. The proxy measurement can be useful for determining the amount of UV irradiation provided to the space.

[0006] The disclosure provides a method for regulating radiation output from a UV radiation source. In various aspects, the method can involve irradiating air of a space with radiation from the UV radiation source, wherein the radiation comprises one or more wavelengths of about 200 nm to about 400 nm; determining an amount of ozone in air of the space; processing the determined ozone amount to obtain a proxy measurement of effective UV irradiation; and adjusting or governing radiation output from the UV radiation source based on the proxy measurement. In various aspects, ozone can be determined by measurement with an ozone detector or it can be determining indirectly by use of a calibration value as described herein.

[0007] The disclosure also provides a system for regulating radiation output from a UV radiation source, comprising: a UV radiation source configured for irradiating air of a space, wherein the UV radiation source emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm; acomponent for determining an amount of ozone in air of the space based on operation of the UV radiation source, such as an ozone detector; a control module configured for processing the determined ozone amount to obtain a proxy measurement of effective UV irradiation, wherein the control module directs the UV radiation source to adjust radiation output based on the proxy measurement.

[0008] The disclosure yet further provides an apparatus for inactivating a pathogen in air of a space, comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, and a control module that regulates the UV radiation. The apparatus comprises a component for determining an amount of ozone in air of the deployment space, and the control module utilizes the determined ozone amount to derive a proxy measurement of effective UV radiation output. In some aspects, the component for determining ozone is an ozone detector. In some aspects, the component for determining ozone is a hardware or software implementation of a calibration value derived from prior measurement

[0009] indirectly determining current ozone amount generated from operation of the apparatus without requiring direct measurement of ozone. In various further aspects, the control module can adjust or govern performance of the UV radiation source based on the , wherein the calibration value is previously determined by: measuring ozone amount in air of a space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof. In various aspects,

[0010] The disclosure also provides an apparatus for inactivating a pathogen in air of a space, comprising: an apparatus for inactivating a pathogen in air of a space, comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, a component for determining an amount of ozone in air of the space, and a control module configured to process the determined ozone amount to obtain a proxy measurement of effective UV irradiation and configured to adjust or govern radiation output of the UV radiation source based on the proxy measurement. In various aspects, the amount of ozone is determined based on (A) inferring ozone amount of air in the space by use of acalibration value having been previously derived from measuring ozone amount in air of a test space while irradiating the air with the UV radiation source or an equivalent source; and processing the measured ozone amount relative to a predicted, calculated, known, or measured amount of UV irradiation provided by the UV radiation source or the equivalent source; (B) contemporaneously measuring the ozone amount in air of the space; or both. Thus, in various aspects, the apparatus can be a calibrated apparatus, which permits accurate determination of ozone levels in a given deployment space without requiring contemporaneous deployment and use of an ozone detector. The disclosure also provides an apparatus comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, and a control module that regulates emitted radiation to provide an ozone concentration in air of the space of at least 0.01 ppb above baseline, an ozone concentration in air of the space of less than 50 ppb overall, or both.

[0011] The disclosure yet further provides a method, system, or apparatus configured for calibrating, testing, or inspecting, a UV radiation source for a space. In various aspects, the method, system, or apparatus can involve determining an amount of ozone in air of the space while operating the UV radiation source. The ozone amount can be processed to obtain a proxy measurement reflecting effective UV radiation provided to the air in the space. Processing can involve evaluation of the determined ozone amount against one or more reference value, ozone profile, and prior measurement. In various aspects, the method, system, or apparatus can subsequently utilize the proxy measurement to score, grade, pass, fail, validate, or batch the UV device. In various aspects, the method, system, or apparatus can subsequently utilize the proxy measurement to adjust or govern radiation output from one or more UV radiation source, an apparatus containing one or more UV radiation source radiation source, or a system containing one or more UV radiation source radiation source.

[0012] Various aspects of the presently described system, method, and apparatus can have one or more of the advantages for treating a space with UV radiation, particularly far-UV radiation: (i) increased accuracy and simplicity of assessing UV radiation; (ii) avoiding errors related to obstruction, occupancy, and human use of the space; (iii) improved safety with respect to UV exposure limits;(iv) improved reliability of germicidal systems with respect to maintaining minimum effective UV flux; (v) real-time monitoring or control; (vi) continuous monitoring or control; (vii) improved set up and calibration of UV devices; (viii) avoiding reliance on UV photometer, spectrometer, or dosimeter to determine UV radiation; (ix) a sensor that can be co-located with the UV source or placed outside the area of direct irradiation; and (x) increased accuracy of measuring germicidal efficacy and effective air changes per hour (eACH) in the space.

[0013] Such systems, methods, and apparatus are useful for providing a way to safely irradiate pathogens in occupied spaces. BRIEF DESCRIPTION OF THE FIGURES

[0014] FIG. 1 illustrates an example of a system including a UV radiation source, an ozone detector, and a control module, which can be useful for calibrating or regulating the UV radiation source based on determined ozone amount.

[0015] FIG.2. illustrates an example of an apparatus including a UV radiation source and an ozone detector.

[0016] FIG. 3 illustrates an example comprising a technique for indirectly assessing UV irradiation using ozone amount.

[0017] FIG. 4 illustrates an example comprising a method for regulating radiation output of a UV radiation source.

[0018] FIG.5 illustrates an example comprising a method for calibrating a UV radiation source.

[0019] FIG.6 illustrates a block diagram of an example comprising a machine upon which any one or more of the methods discussed herein may be performed.

[0020] FIG.7 provides a plot illustrating changes in ozone concentration over time and in relation to performance of a UV radiation source.

[0021] FIG. 8 provides a plot of ozone concentration over time for a space equipped with a UV radiation source.

[0022] FIG. 9 provides a plot of ozone concentration over time for a space equipped with multiple UV radiation sources and illustrating changes in ozone concentration over time and in relation to performance of a UV radiation source.

[0023] FIG. 10A and 10B provide a diagram summarizing one example of how direct ozone measurements can be used to assess irradiance, radiant flux, radiant exposure, germicidal efficacy, and eACH, and do so with the benefit of reflecting the effective action of far-UV light upon the treated air.

[0024] FIG. 11 illustrates an example of a system including a UV radiation source, one or more components for detecting or modulating an amount of ozone in the space, and a control module, which can be useful for calibrating or regulating the UV radiation source based on determined ozone concentrations.

[0025] FIG. 12. illustrates an example of an apparatus including a UV radiation source with a control module configured to obtain a proxy measurement of radiation output based on an amount of ozone in a space where the device is deployed.

[0026] FIG. 13 illustrates an example comprising a method for regulating radiation output of a UV radiation source by using ozone content to determine effective radiation output.

[0027] FIG. 14 illustrates an example comprising a method for regulating radiation output of a UV radiation source involving indirectly determining ozone content via use of a calibration value.

[0028] FIG. 15 illustrates an example comprising a method for passing, failing, scoring, batching, validating, grading, or calibrating the output of the UV radiation source based on a proxy measurement of radiation output derived from the ozone in a space. DETAILED DESCRIPTION OF THE INVENTION

[0029] Monitoring and control of UV irradiation, including far-UV irradiation, can be useful for managing the safety and efficacy of germicidal UV devices. Far-UV light in particular is a promising germicidal platform due its ability to safely inactivate pathogens without deeply penetrating human skin and tissue. Safe and efficient implementation of far-UV irradiation should involve measuring and controlling the amount of far-UV irradiation provided to an irradiated space and its occupants. Such control has benefits in the context of assuring germicidal efficacy and also limiting excessive occupant exposure. The ACGIH (American Conference of Governmental Industrial Hygienists) currentlysets Threshold Limit Values for the amount of 222nm Far UV exposure, which in some examples of far-UV radiation sources is about 161 mJ / cm² for the eyes and about 479 mJ / cm² for skin over an 8 hour period, yet this technology may be useful for disinfecting airborne pathogens at significantly lower ranges of exposure.

[0030] Directly measuring the amount of UV irradiation provided to a space can be difficult, especially in non-laboratory contexts. It can be even more difficult to measure the amount of UV radiation that is actually interacting with air and particles therein. Conventional approaches to determining far-UV irradiation has followed two approaches: (1) use of a photometer, spectrometer, or dosimeter to obtain measurements, which can be extrapolated to a larger space such as by determining the average of measured irradiance projected into a cone; and (2) using chemical actinometry, such as by using tetrachloroethylene as the actinometer. See, e.g., Poppendieck et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 675^679; Jimenez et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 668^674; and Barber et al., ChemRxiv. Jul. 18, 2023, each of which are incorporated by reference here with. However, such approaches can have various disadvantages, such as the need for specialized equipment, difficulty in obtaining measurements in complex spaces, limitations in measuring the actual germicidal effectiveness of a UV source, limitations in measuring the actual exposure on occupants in the space, and a disconnect between radiation output from the source and the realized effective irradiance of air in the treated space. For example, using a photometer, spectrometer, or dosimeter can require physical placement of the device within an area of direct irradiation, which can create complexities for large and dynamic environments. Chemical actinometry can involve strictly controlled conditions and use of chemical agents that can be unsuitable for areas occupied by people. A powerful advantage of far-UV light is that it can be useful in occupied, active spaces. Yet, those same types of spaces can present challenges with respect to obstructions, clutter, changes in air volume, changes in air exchange, and human interactions. Conventional approaches for measuring far-UV irradiance are poorly suited for human-use or occupied spaces.

[0031] The present disclosure provides a solution for measuring and assessing UV irradiation in a space by utilizing ozone concentrations as a proxy measurement for UV irradiation. In various aspects, it provides a solution to theproblem of measuring and assessing far-UV irradiation in a human-occupied space by utilizing ozone concentrations as a proxy measurement for far-UV irradiation. The disclosure also provides systems, apparatus, and methods that utilize this technique for calibrating or regulating a UV radiation source. Definitions

[0032] Throughout this document, values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of ^about 0.1% to about 5%^ or ^about 0.1% to 5%^ should be interpreted to include not just about 0.1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement ^about X to Y^ has the same meaning as ^about X to about Y,^ unless indicated otherwise. Likewise, the statement ^about X, Y, or about Z^ has the same meaning as ^about X, about Y, or about Z,^ unless indicated otherwise.

[0033] In this document, the terms ^a,^ ^an,^ or ^the^ are used to include one or more than one unless the context clearly dictates otherwise. The term ^or^ is used to refer to a nonexclusive ^or^ unless otherwise indicated. The statement ^at least one of A and B^ or ^at least one of A or B^ has the same meaning as ^A, B, or A and B.^ In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.

[0034] In the methods described herein, the acts can be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doingY can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0035] The term ^about^ as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range, and includes the exact stated value or range.

[0036] The term ^substantially^ as used herein, depending on context, can refer to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%.

[0037] In the methods described herein, the acts can be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0038] As used herein, the term ^pathogen^ includes viruses, bacteria, infectious microbes, fungi, protozoa, parasites, and other agents, or components thereof, that are capable of causing disease or infection in humans or animals. Pathogens includes pathogens in droplets, pathogens in aerosols, and free pathogens in air.

[0039] As used herein, the term ^inactivation^ refers to a partial or complete reduction in a pathogen^s ability to cause disease or infection. Without intending to limit to any particular theory of mechanism, inactivation may be achieved by damaging or destroying the pathogen^s genetic material, membrane, or other structures through exposure to UV radiation (e.g., far-UV radiation). In some contexts, inactivation can refer to inactivating a pathogen^s ability to reproduce, replicate, enter a cell, or evade the immune system. Inactivation of pathogens can be useful for disinfection or decontamination purposes.

[0040] As used herein, the term ^space^ and ^space^ refers to a space being irradiated. Typically in this document, the space is irradiated to inactivate pathogens in the air of said space, yet in some aspects the space can be irradiated for testing, inspecting, batching, validating, or grading. Specifically, the space canbe irradiated to derive a calibration value for the tested device or an equivalent device. This document does not intend for the term ^space^ to necessarily require the presence of pathogens or a particular intent to disinfect; however, in certain contexts it may be useful to describe a given space as a ^test space^ to distinguish a first environment used for testing, inspecting, batching, validating, or grading, from a second environment where the device would be employed as an end-use (e.g., a human-use space). Typically, the air of the space includes the entire volume of the space, e.g., a room, as such air readily mixes and treatment of a given space is typically configured to provide a germicidal effect to the entire space not simply a subsection thereof. The terms ^human-use space^ or ^occupiable space^ refer to an area that is designed or intended for use by humans. Examples include, but are not limited to, rooms, restaurants, schools, workplaces, offices, hospitals, cafeterias, event space, bars, theaters, gyms, retail space, public transportation vehicles, public transportation stations, airports, and airplanes. Human-use space or occupiable space can include indoor space and outdoor space. Human-use space or occupiable space can be empty, or it can be occupied space, for example by one or more occupants. Indoor space can include indoor space that is open, ventilated, or non-ventilated. In various examples, indoor space can have windows, or mechanical ventilation such as a HVAC system including air supplies and air returns. An occupiable space or occupied space can also refer to an animal- use space or plant-use space. Occupiable space can have certain areas expected to be occupied. In various aspects, areas of an occupiable space that may be expected to be occupied can include seats, desks, tables, bar tops, waiting areas, patient beds, reception space, checkout areas, cubicles, stairways, walkways, and elevators. Typically, areas of expected human occupancy are less than 7 feet from a floor.

[0041] Various components described herein may be combined to carry out a machine process. Various components described herein can refer to a physical entity or a software entity having boundaries defined by function or subroutine calls, branch points, APIs, or other technologies that provide for the partitioning or modularization of particular processing or control functions. A component may be a packaged functional hardware unit designed for use with other components and a part of a program that usually performs a particular functionof related functions. Components may constitute either software components (e.g., code embodied on a machine-readable medium) or hardware components. A "hardware component" is a tangible unit capable of performing certain operations, and may be configured or arranged in a certain physical manner. In examples, one or more computer systems (e.g., a standalone computer system, a client computer system, or a server computer system) or one or more hardware components of a computer system (e.g., a processor or a group of processors) may be configured by software (e.g., an application or application portion) as a hardware component that operates to perform certain operations as described herein. A hardware component may also be implemented mechanically, electronically, or any suitable combination thereof. For example, a hardware component may include dedicated circuitry or logic that is permanently configured to perform certain operations. A hardware component may be a special-purpose processor, such as a field-programmable gate array or an application specific integrated circuit. A hardware component may also include programmable logic or circuitry that is temporarily configured by software to perform certain operations. For example, a hardware component may include software executed by a general-purpose processor or other programmable processor. Once configured by such software, hardware components become specific machines (or specific components of a machine) uniquely tailored to perform the configured functions and are no longer general-purpose processors. A decision to implement a hardware component mechanically, in dedicated and permanently configured circuitry, or in temporarily configured circuitry (e.g., configured by software), may be driven by cost and time considerations. Accordingly, the phrase "hardware component" (or "hardware-implemented component") should be understood to encompass a tangible entity that is physically constructed, permanently configured (e.g., hardwired), or temporarily configured (e.g., programmed) to operate in a certain manner or to perform certain operations described herein. Considering examples in which hardware components are temporarily configured (e.g., programmed), each of the hardware components need not be configured or instantiated at any one instance in time. For example, where a hardware component comprises a general-purpose processor configured by software to become a special-purpose processor, thegeneral-purpose processor may be configured as different special-purpose processors (e.g., comprising different hardware components) at different times. Software accordingly configures a particular processor or processors, for example, to constitute a particular hardware component at one instance of time and to constitute a different hardware component at a different instance of time. Hardware components can provide information to, and receive information from, other hardware components. Accordingly, the described hardware components may be regarded as being communicatively coupled. Where multiple hardware components exist contemporaneously, communications may be achieved through signal transmission (e.g., over appropriate circuits and buses) between or among two or more of the hardware components. In examples in which multiple hardware components are configured or instantiated at different times, communications between such hardware components may be achieved, for example, through the storage and retrieval of information in memory structures to which the multiple hardware components have access. For example, one hardware component may perform an operation and store the output of that operation in a memory device to which it is communicatively coupled. A further hardware component may then, at a later time, access the memory device to retrieve and process the stored output. Hardware components may also initiate communications with input or output devices, and can operate on a resource (e.g., a collection of information).The various operations of example methods described herein may be performed, at least partially, by one or more processors that are temporarily configured (e.g., by software) or permanently configured to perform the relevant operations. Whether temporarily or permanently configured, such processors may constitute processor-implemented components that operate to perform one or more operations or functions described herein. As used herein, "processor-implemented component" refers to a hardware component implemented using one or more processors. Similarly, the methods described herein may be at least partially processor-implemented, with a particular processor or processors being an example of hardware. For example, at least some of the operations of methods described herein may be performed by one or more processors or processor-implemented components. Moreover, the one or more processors may also operate to support performance of therelevant operations in a "cloud computing" environment or as a "software as a service" (SaaS). For example, at least some of the operations may be performed by a group of computers (as examples of machines including processors), with these operations being accessible via a network (e.g., the Internet) and via one or more appropriate interfaces (e.g., an API). The performance of certain of the operations may be distributed among the processors, not only residing within a single machine, but deployed across a number of machines. In some examples, the processors or processor-implemented components may be located in a single geographic location (e.g., within a home environment, an office environment, or a server farm). In some examples, the processors or processor-implemented components may be distributed across a number of geographic locations. A "computer-readable medium" or ^machine-readable medium^ refers, for example, to one or more tangible storage devices and media (e.g., a centralized or distributed database, and associated caches and servers) that store executable instructions, routines and data. The term specifically excludes intangible carrier waves, modulated data signals, and other such media, at least some of which are covered under the term "signal medium." The term shall accordingly be taken to include, but not be limited to, solid-state memories, and optical and magnetic media, including memory internal or external to processors. Additionally, one or more device or component described herein may include, or may operate by, logic or a number of components, or mechanisms. Such device or component may have circuitry specifically adapted for utilizing ozone as a proxy measurement for determining far-UV irradiation or for performing a method described herein. ^Circuitry^ refers generally a collection of circuits implemented in tangible entities that include hardware (e.g., simple circuits, gates, logic elements, etc.). Circuitry membership may be flexible over time and underlying hardware variability. Circuitries include members that may, alone or in combination, perform specified operations when operating. In an example, hardware of the circuitry may be immutably designed to carry out a specific operation (e.g., hardwired). In various examples, the hardware comprising the circuitry may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) including a computer readable medium physically modified (e.g., magnetically, electrically, such as via a change inphysical state or transformation of another physical characteristic, etc.) to encode instructions of the specific operation.

[0042] As used herein, the term ^ultraviolet radiation^ or ^UV radiation^ refers to electromagnetic radiation having one or more wavelength of about 100 nm to about 400 nm. UV radiation can further be subdivided into several categories based on wavelength: UVA (about 315 nm to about 400 nm), UVB (about 280 nm to about 315 nm), UVC (about 200 nm to about 280 nm), far-UV (about 200 nm to about 230 nm), vacuum UV (about 100 nm to about 200 nm), extreme UV (about 10 nm to about 100 nm). ^Germicidal UV^ can refer to about 200 nm to about 400 nm. In various aspects and contexts, UV radiation can refer to various sub-ranges of UV radiation, for example, 180 nm to 400 nm, 200 nm to 400 nm, 210 nm to 400 nm, 200 nm to 370 nm, 200 nm to 300 nm, 200 nm to 230 nm, 200 nm to 240 nm, 210 nm to 230 nm, or 210 nm to 280 nm. Radiation sources suitable for the presently described apparatus, system and method would not typically emit vacuum UV or extreme UV. Indeed, in various aspects, the radiation sources are configured so as to not emit certain wavelengths, such as one or more of UVA, UVB, UVC, far-UV, vacuum UV, extreme UV, visible light, or wavelengths longer than 400 nm, or wavelengths shorter than 100 nm. For example, the UV radiation source can emit radiation comprising or substantially consisting of one or more wavelengths between 200 nm and 400 nm. A given radiation source can emit a spectrum having wavelengths according to multiple categories of light. For example, a far-UV radiation source may emit radiation having wavelengths corresponding to UVA, UVB, or UVC. The far- UV radiation sources described in the present disclosure can provide a range of wavelengths of UV radiation. In some aspects, the UV radiation sources, including far-UV radiation sources, can emit visible light or be coupled together with a secondary light source that emits visible light. In various aspects, the UV radiation sources can emit radiation having at least one wavelength from 210 nm to 230 nm. In various aspects, the UV radiation sources can emit radiation having at least one wavelength from 240 nm to 280 nm and at least one wavelength from 210 nm to 230 nm. In various aspects, the far-UV radiation sources can emit radiation having at least one wavelength from 210 nm to 230 nm. In further aspects, far-UV radiation sources can emit radiation having atleast one wavelength outside of 200 nm to 230 nm. In yet further aspects, the far-UV radiation sources can emit radiation having at least one wavelength from 230 nm to 280 nm.

[0043] As used herein, the term ^visible light^ is defined as light having a wavelength of from 380 nm to 750 nm. In some alternative examples, visible light can have a wavelength greater than 380 nm and up to 700 nm, or greater than 400 nm and up to 700 nm. In various examples, the far-UV radiation source, apparatus, and the like, relate to electromagnetic radiation that is outside of the visible light range. In various examples, the far-UV radiation source produces far-UV radiation but not visible light, and the filter can be configured to pass or stop various wavelengths of far-UV radiation, but need not necessarily pass or stop visible light. Yet, in various other aspects, the far-UV radiation source, apparatus, and the like, can further involve a visible light source and visible light emission.

[0044] As used herein, ^UV irradiation^ refers to UV radiation delivered to a space from one or more UV radiation source. ^Far-UV irradiation^ refers to far- UV radiation delivered to air in a space from one or more far-UV radiation source. For comparison, ^UV output^ and ^radiation output^ may refer to radiation emitted from one or more UV source, but may differ from the amount of UV effectively acting upon the air in the space. UV irradiation, including far-UV irradiation, can be difficult to accurately calculate based only on the specifications or configuration of a given radiation source. UV irradiation, including far-UV irradiation, can also be difficult to accurately measure if relying merely on the result of a photometer, spectrometer, or dosimeter. For example, a UV radiation source emission can result in inhomogeneous light spatial distributions, different spaces can have different reflectivity of materials at the various UV wavelengths, and there can be variation with respect to obstructions and air motion. Different spaces and environments are affected by UV irradiation, including far-UV irradiation, in different ways and an amount of UV radiation that is effective in one space may not be an effective amount of UV radiation in another space. There are various ways to quantify and qualify UV irradiation, including: irradiance, radiant flux (total optical power), effective air changes per hour, and germicidal efficacy with respect to a particular pathogen. As used herein, ^effective UV irradiation^ refers to the useful amount of irradiation acting on the space from oneor more UV radiation source. As used herein, ^effective far-UV irradiation^ refers to the useful amount of irradiation acting on the space from one or more far-UV radiation source. As such, the ^effective^ irradiation can differ from an amount of radiation that is emitted from one or more UV radiation source. Similarly, the ^effective^ far-UV irradiation can differ from an amount of UV radiation that is detected by a photometer, spectrometer, or dosimeter located in the space, because a photometer, spectrometer, or dosimeter receiving (or failing to receive) direct irradiation from the lamp may not accurately reflect a representative amount of light delivered to the air throughout the space. The methods described herein can have the advantage of providing effective UV irradiation, including effective far- UV irradiation, rather than expected UV irradiation or UV irradiation that is delivered to a photometer, spectrometer, or dosimeter. Various examples provide a more accurate measurement of effective far-UV irradiation compared to measurements based on recordings from a photometer, spectrometer, or dosimeter. UV irradiation and far-UV irradiation can also be used in a non- measurement context, such as to refer to the application or the rate of application of radiation to a space.

[0045] As used herein, ^irradiance^ is a measurement of power delivered to a certain surface area in units of ^W / m2^ (watts per square meter), mW / m2or µW / cm2. As a certain surface area moves away from a light source the power delivered to it decreases as the square of the distance. This can be arrived at from a radiance value by specifying a distance for the irradiance value. This can be arrived at from total optical power with knowledge of the distance from the source and the relative position of the surface in the radiation pattern of the source. Under a fixed spectra this can be equated with a certain photon arrival rate for a certain surface area in photons / (second^cm2). Irradiance as used herein is used in a ^radiant^ context integrated over a relevant germicidally effective UV spectral range, e.g., often conveniently integrated across 180 nm to 400 nm. In various aspects, total irradiance is useful for determining an instantaneous amount of radiation provided to a space or for determining an average amount of radiation provided to a space over a given period of time

[0046] As used herein, ^radiant exposure^ is a measurement of energy delivered to a certain surface area in units of ^J / m2^ or joules per square meter.This expresses the amount of energy delivered to a surface. This can be arrived at from an irradiance by specifying an amount of time to integrate over. Under a fixed spectra this can be equated with a certain photon arrived photon count for a certain area in photons / cm2. Exposure can be useful for correlating to threshold limit values (TLV). Exposure can be determined based on assuming a 222 nm narrow-band light source or based on a weighted integration of a multispectral source. Spectral weighting factors can be selected as suitable for a given use case: for example contribution to exposure limits, germicidal efficacy, or ozone generation. For example, when determining exposure in the context of a TLV value, a narrow-band 222 nm source may be approximated as 222 nm light compared against a TLV for 222 nm light. A broader band spectrum of a UV light source may be integrated across the broad band spectrum and weighted at each wavelength according to how each wavelength contributes to exposure relative to 222 nm light.

[0047] As used herein, ^radiant flux^, ^total optical power^, or ^total optical power^ is a measurement of the total power output of a lamp or other radiating device. This measures the total power output of the lamp in units of ^W^ or watts. This is distinct from the ^wall power^ consumption of the lamp which is not related to this term in any meaningful way besides bounding it above. Under a fixed spectra this can be equated with a certain photon generation rate in photons / second. ^Radiant flux^, ^total optical power^, or ^total optical power^ used herein is used in a ^radiant^ context integrated over a relevant germicidally effective UV spectral range, e.g., often conveniently integrated across 180 nm to 400 nm.

[0048] As used herein, ^ppb^ refers to parts per billion, which refers to a volumetric mixing ratio. For example, a 1 Liter volume of air with a 1 ppb ozone concentration would contain 1 nanoLiter of ozone. Ozone concentration can also be measured in units of mass per volume, such as ^ug / m3^ or micrograms per meter. Assuming standard temperature and pressure, 1 ppb is approximately 2 ug / m3. See, e.g., Poppendieck et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 675^679. UL2998 sets a 5 ppb ozone threshold for validating a device as low / no ozone emission. Various national agencies have set an exposure limit for ozone of 50-70 ppb. Ozone production rate can be measured in ^ug / h^ or microgramsper hour. This is an absolute production rate. It can also be measured in ^ppb / hr^ or parts per billion (volumetrically) per hour under a fixed volume. Various other units of concentration can also be suitably used to describe the concentration of ozone or other components in the air of a space.

[0049] As used herein, ^ACH^ is a measure of the rate at which the air volume of a space is mechanically exchanged with ^outside^ air. It is measured LQ^XQLWV^RI^LQYHUVH^KRXUV^^Kí^^^ZKLFK^LV^FRPPRQO\^H[SUHVVHG^DV^WKH^XQLW^µ$&+¶^^ A value of 1 ACH means that over an hour an amount of gas is exchanged without outside equal to the volume of the space, so for a 3000 cu. ft. office 3000 cu. ft. would be exchanged. Note that ^ since this is a continuous process ^ the air will mix as it is exchanged diluting but not eliminating pollutant and pathogenic content. This means that 1 ACH does not result in complete removal RI^SROOXWDQW^DQG^SDWKRJHQLF^FRQWHQW^DIWHU^^^KRXU^^EXW^DQ^DWWHQXDWLRQ^E\^^^í^ H[S^í^^^ ^^^^^^$GGLWLRQDOO\^^ZKHQ^SROOXWDQW^FRQWHQW^LV^SUHVHQW^LQ^WKH^RXWVLGH^DLU (for example trace atmospheric ozone) this also contributes to the attenuation rate. ACH can be determined from cubic feet of ventilation per minute (CFM) x 60 / volume of the space. In various contexts, ACH can be better understood by referring to ASHRAE Standard 62 and ANSI Standard 136, each of which are incorporated by reference herewith.

[0050] As used herein, ^eACH^ is a measure of the rate at which pollutants or pathogens are removed from a space. It describes the mechanical ventilation rate that would achieve an equivalent reduction in pollutants or pathogens. It has the same units as ACH. eACH is relevant when pathogens and pollutants are removed by non-ventilation means such as filters or inactivation by UV lights. For example in a sealed space (i.e., 0 ACH) the value 1 eACH would report that the rate at which pollutants or pathogens are removed by a certain air-cleaning intervention could also have been achieved (absent that intervention) by mechanical ventilation at the rate of 1 ACH. In various contexts, eACH may report the removal rate for a certain class of pathogen or pollutant. For example, 60 eACH achieved with UV irradiation reports the rate at which pathogenic viral particles of a certain type are removed (by inactivation) but does not indicate a similar removal rate for airborne particulate or ozone. Similarly, an ozone scrubber may remove ozone at a rate of 20 eACH while not removing pathogenic particles at all.

[0051] In the context of infectious disease, eACH can serve to equate the effect of inactivating pathogens and removing pathogens. The resulting value is an ACH equivalent determined by combining the ACH of the given space together with an irradiation-derived ACH equivalent value. In context of inactivating pathogens, the eACH refers to an ACH equivalent number of times the entire volume of air within a given space, e.g., a room, would need to be replaced with filtered air in one hour to obtain an equivalent result with respect to eliminating active pathogens.

[0052] As used herein, ^germicidal efficacy^ is a measurement of the fraction of a pathogen inactivated (rendered non-pathogenic) by a certain procedure. This is a unitless ratio where the value of 0 represents no inactivation and the value of 1 represents complete inactivation. It can be expressed as a percentage where ^ ^^^DQG^^ ^^^^^ This can also be expressed as a survival fraction, which is the fraction of a pathogen not inactivated (i.e., remaining pathogenic.) These can be interconverted by subtracting the value from 1: i.e., VXUYLYDO^ IUDFWLRQ^ ^ ^^ í germicidal efficacy, and JHUPLFLGDO^HIILFDF\^ ^^^í survival fraction. This can also be expressed as a certain ^n-log^ inactivation, which expresses the base-10 log of the survival fraction. For example, a 99.9% inactivation yields a survival fraction RI^^^^^^ ^^^^^^^ ^^H-^^ ^^3-log disinfection^. Various methods, systems, and apparatus of the present disclosure can achieve a germicidal efficacy of 99.9% or 3-log disinfection.

[0053] As used herein, ^baseline^ ozone is used for the purpose of differentiating ozone from sources other than the far-UV device for which far-UV irradiation is being measured. As used herein, ^background^ ozone is used for the purpose of differentiating between ozone from natural or pervasive sources. Background ozone keyed to geographic location is available from government agencies. UV Measurement and Control

[0054] Reference will now be made in detail to certain embodiments of the disclosed subject matter, examples of which are illustrated in part in the accompanying drawings. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplifiedsubject matter is not intended to limit the claims to the disclosed subject matter. Aspects of the present disclosure can be realized by various examples, some of which are provided in the drawings, but a person skilled in the art would readily appreciate that the specific examples provided herein are neither limiting nor exhaustive, and that any number of additional variations can be immediately envisaged as falling within the spirit of the invention. The various examples and drawings illustrated herein can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using combinations of those elements shown or described, either with respect to a given example, or with respect to other examples shown or described herein. Use of headers in this document is not intended to limit the subject matter in any way, and it is further contemplated that the various aspects discussed with respect to one particular illustrated example can be envisaged with respect to each other.

[0055] FIG. 1 illustrates an example of a system that is useful for assessing, measuring, calibrating, or controlling UV irradiation, exemplified as a non- limiting example of using a far-UV radiation to treat air in a human-occupied space. A far-UV radiation apparatus 100 provides a far-UV radiation source 101, which is configured to irradiate a space 110. Far-UV radiation generates ozone in air of the space. The generated ozone is monitored and measured by an ozone detector 140, which is in communication with a control module 130. The control module 130 serves as an interface between the ozone detector and the far-UV radiation source. The control module 130 is configured to receive data from the ozone detector 140 and process it according to one or more reference values or model profiles to obtain a result that can function as a proxy measurement for the amount of effective far-UV irradiation in the space 110. When more than one far- UV radiation apparatus is present, the proxy measurement can correspond to the amount of effective far-UV irradiation in the space 110 provided by a particular far-UV radiation source 100. Based on a proxy measurement, the control module 130 transmits a signal to instruct the far-UV radiation apparatus 100 to regulate far-UV radiation output. Regulating radiation output from the far-UV radiation 100 can take the form of increasing, decreasing, or maintaining far-UV radiationoutput. In various aspects, the far-UV radiation source 101 receives power from a power supply 120 and, optionally, a driver 125, any of which may be configured to receive instructions from the control module 130 to modulate the power supplied to the far-UV radiation source 101 and thus regulate radiation output. In various aspects, the far-UV radiation source 100 comprises a power supply 120, a driver 125, or both, regulated by the control module 130 in response to a signal based on the proxy measurement. The system can optionally include additional far-UV radiation sources, ozone detectors, and control modules, as well as additional sensors for detecting parameters other than ozone concentration.

[0056] One or more ozone measurement is recorded by an ozone detector 140 and transmitted to a control module 130. In various aspects, the control module 130 can process the one or more ozone measurements to obtain actionable information with respect to operation of the far-UV radiation source 101 For example, the control module 130 can process the one or more ozone measurements to determine whether to increase, decrease, or maintain far-UV radiation output from a far-UV radiation source 101, and it can subsequently send such instructions to modulate the far-UV radiation source 101 accordingly. In various aspects, the control module 130 can process the one or more ozone measurements to determine how to suitably adjust, calibrate, or install the far-UV radiation source 101 for the space. In yet further aspects, the control module 130 can process the one or more ozone measurements to monitor the far-UV radiation source 101 to assure proper functioning or for maintenance purposes.

[0057] The far-UV radiation source 101 can utilize various technologies, including one or more bulbs, light-emitting diodes (LEDs), or other sources configured to emit UV radiation in an amount effective to inactivate pathogens in air. The radiation is typically transmitted through a transparent substrate optionally comprising an optical filter. The optical filter can be disposed directly onto a far-UV generating bulb, or disposed upon a window or lens through which the apparatus emits far-UV radiation. The far-UV radiation source 101 can include one or more excimer bulb. Excimer bulbs can include a combination of a rare gas and halogen which emits one or more wavelength of far-UV light when excited by an electrical stimulus. Excimer bulbs excitation can be triggered in various ways including, for example, glow discharge, pulsed discharge, dielectric barrierdischarge, short arc, or combinations thereof. In various examples, the far-UV radiation source comprises a KrCl excimer bulb or a KrBr excimer bulb. The far- UV radiation source 101 generates and emits radiation comprising one or more wavelengths of about 200 nm to about 280, about 210 nm to about 230 nm, and / or about 222 nm. Other wavelengths may be emitted as well. In some examples, the far-UV radiation source 101 can be a source that provides a peak unfiltered emission between 200 nm to 280 nm, such as 222 nm. In some examples, the far- UV radiation source 101 is configured to emit some amount of 254 nm light. In some emissions profiles, including longer wavelength light such as 254 nm may facilitate the presently described method utilizing ozone detection, although it is not necessary. In various further examples, the far-UV radiation source 101 can emit UV wavelengths other than far-UV. In some examples, it can emit visible light. In further examples, the excimer bulb generates and emits 222 nm light. Various shapes of bulbs are possible. Bulbs are typically substantially tube-like, and can be rod-shaped, oblong, toroidal, or flattened versions of the same. The far-UV radiation source 101 can include a bulb having an annular body having an outer surface and defining an internal discharge cavity, wherein the annular body has a major axial dimension and a minor radial dimension, and comprises an electrode in the internal discharge cavity that traverses along the major axial dimension of the annular body. Krypton chloride excimer lamps typically emit a peak emission at 221.8 nm, but convention in the art is to refer to such emission as 222 nm. The far-UV radiation source 101 can include a housing, the form of which is not particularly restrictive. Typically, the far-UV radiation source 101 includes a housing containing one or more bulb. In various aspects, the housing partially encloses the one or more bulb and provides at least one opening through which radiation can be emitted. For example, the housing can be a box where one face has an opening that is covered by a UV-transparent material serving as a protective window. The window can be substantially planar, or it can be curved. The window can be a crystal such as quartz, or a glass such as fused silica. In some aspects, the window can be CORNING® 7980 or HERAUS SUPRASIL®. The window can be coated with an optical filter. The far-UV radiation source 101 can further include any number of optical components, such as optical filters, reflectors, diffusers, and lenses. For example, the inside of the housing can befurnished with reflectors to direct light out the housing and maximize emitted radiation. As another example, the far-UV radiation source 101 can include one or more component for adjusting the direction, intensity, or focus of the emitted light. The far-UV radiation source 101 can include a diffuser or lens.

[0058] The far-UV radiation source 101 can be configured such that germicidal wavelengths are transmitted while harmful wavelengths are controlled. For example, the apparatus can be configured such that when used in an apparatus that generates UV light providing radiation upon human eyes or skin of less than or about 1 mJ / cm2, 10 mJ / cm2, 20 mJ / cm2, 30 mJ / cm2, 40 mJ / cm2, 50 mJ / cm2, 60 mJ / cm2, 70 mJ / cm2, 80 mJ / cm2, 90 mJ / cm2, 1000 mJ / cm2, 110 mJ / cm2, 120 mJ / cm2, 130 mJ / cm2, 140 mJ / cm2, 150 mJ / cm2, or 160 mJ / cm2at a wavelength of 200 nm to 400 nm, or a wavelength of 210 nm to 230 nm, when measured at its intended distance from a person over an anticipated maximum exposure period, such as an 8 hour period, with such exposure values based on assuming a 222 nm narrow-band light source or based on a weighted integration of a multispectral source. Spectral weighting factors can be selected as suitable for a given use case: for example contribution to exposure limits, germicidal efficacy, or ozone generation. The apparatus can be configured such that when used in an apparatus that generates UV light providing radiation upon human eyes or skin of less than or about 1 mJ / cm2, 2 mJ / cm2, 3 mJ / cm2, 4 mJ / cm2, 5 mJ / cm2, 6 mJ / cm2, 7 mJ / cm2, 8 mJ / cm2, 9 mJ / cm2, or 10 mJ / cm2between a wavelength of 240 and 280 nm. As a further example, the apparatus can be configured such that the emitted radiation is about 0.5 µW / cm2to about 60 µW / cm2at one or more occupant or area of expected occupancy, for example, about, at least, or less than 0.5 µW / cm2, 0.6 µW / cm2, 0.7 µW / cm2, 0.8 µW / cm2, 0.9 µW / cm2, 1.0 µW / cm2, 1.5 µW / cm2, 2.0 µW / cm2, 2.5 µW / cm2, 3.0 µW / cm2, 3.5 µW / cm2, 4.0 µW / cm2, 4.5 µW / cm2, 5, µW / cm2, 6 µW / cm2, 7 µW / cm2, 8 µW / cm2, 9 µW / cm2, 10 µW / cm2, 11 µW / cm2, 12 µW / cm2, 13 µW / cm2, 14 µW / cm2, 15 µW / cm2, 16 µW / cm2, 17 µW / cm2, 18 µW / cm2, 19 µW / cm2, 20 µW / cm2, 21 µW / cm2, 22 µW / cm2, 23 µW / cm2, 24 µW / cm2, 25 µW / cm2, 26 µW / cm2, 27 µW / cm2, 28 µW / cm2, 29 µW / cm2, 30 µW / cm2, 35 µW / cm2, 40 µW / cm2, 45 µW / cm2, 50 µW / cm2, 55 µW / cm2, or 60 µW / cm2based on assuming 222 nm narrow-band light source or based on a weighted integration of a multispectral source. Spectral weighting factors can beselected as suitable for a given use case: for example contribution to exposure limits, germicidal efficacy, or ozone generation. The far-UV apparatus 100 can be configured such that when deployed in an occupied space, the emitted radiation provides the intensity, power, effective irradiance, total irradiance, or total optical power sufficient to inactivating pathogens in air. The far-UV apparatus 100 can be configured such that when deployed in an occupied space, the emitted radiation lacks an intensity, power, effective irradiance, total irradiance, or total optical power beyond the ACGIH threshold limits for far-UV radiation or other radiation. In some aspects, the far-UV apparatus 100 can be configured such that when deployed in an occupied space, the emitted radiation lacks the intensity, power, effective irradiance, total irradiance, or total optical power necessary for inactivating pathogens on the skin or other surface of an occupant. The far-UV apparatus 100 can be configured such that when deployed in an occupied space, the emitted radiation lacks the intensity, power, effective irradiance, total irradiance, or total optical power necessary for inactivating pathogens on objects or surfaces in the space. The UV radiation source can be configured to duty cycle between active periods and inactive periods to control exposure.

[0059] The ozone detector 140 can be configured to detect ozone concentration. Ozone detectors can utilize various technological approaches to measuring ozone. For instance, one example approach utilizes a comparison between a scrubbed sample of ozone with a UV-irradiated sample of ozone. In such configuration, the ozone detector 140 receives air from the space and directs a first air sample to an ozone scrubber to remove ozone and then pass the scrubbed air into an absorption cell to measures absorption of radiation from a 254-nm Hg lamp. The absorption is then compared with a second air sample that bypassed the ozone scrubber before passing through the absorption cell. The air samples and measurements can be done sequentially or simultaneously. Such a configuration of ozone detector 140 identifies ozone concentration based on the difference in absorption. One example of a suitable ozone detector 140 is a 2B technologies Model 205 available from 2B Technologies (Boulder, CO). In indoor environments, ozone levels are typically determined based on the contributions of ozone-generating devices and ozone-removing devices, and passive removal ofozone by the environment or introduction from environmental sources is a minor or negligible contributor to indoor ozone level.

[0060] The ozone detector 140 can obtain measurements by continuous measurements or by taking measurements at various sampling intervals. Measurements can be performed on the seconds scale, minutes scale, hours scale, or days scale. For example, measurements can be performed at least or about every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 seconds, at least or about every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes, at least or about every 1, 2, 3, 4, 5, 6, 7, 8, 12, 18, or 24 hours, or at least or about every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 20, 30, or 31 days. In most cases, a suitable ozone detector 140 should be capable of measuring differences in ozone concentration below 100 ppb in order to ascertain relevant differences in ozone concentration with respect to baseline, background, or other ozone sources. Each ozone measurements may be obtained via a variety of sampling techniques. Measurements can correspond to ozone concentration in a single air sample, or an ozone concentration calculated from multiple air samples. Use of multiple samples and multiple measurements can be useful for avoiding noise. In various aspects, an ozone sample or measurement can correspond to the mean, median, mode, statistical weighting, or trendline of values taken over 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 seconds, or over 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes, or over 1, 2, 3, 4, 5, 6, 7, 8, 12, 18, or 24 hours, over 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 20, 30, or 31 days, or over the course of months. In some aspects, measurements are taken every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 seconds, or every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes, or every 1, 2, 3, 4, 5, 6, 7, 8, 12, 18, or 24 hours, or every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 20, 30, or 31 days, or monthly.

[0061] Multiple measurements can also be used to identify the rate of change in ozone over a period of time. Rate of change is useful for determining ozone generation. Data can be logged in a memory of the ozone detector 140 or delivered to the control module 130. A high level of ozone measurement precision can be useful in practicing the methods, systems, and apparatus described herein. Invarious aspects, the ozone detector 140 has a precision of at least or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 20 ppb. In various further aspects, the ozone detector 140 has a precision of at least or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 20 ppb over 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 second averaging, or over 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minute averaging. The ozone detector 140 can have a resolution of at least or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5, 6, 7, 8, 9, or 10 ppb. The ozone detector 140 can have a flow rate of at least or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5, 6, 7, 8, 9, or 10 ppb. Measuring can typically be conducted anywhere within the air of the treatment as air mixing is generally fast. Measuring can be conducted in the area of direct irradiation or outside the area of direct irradiation. In some aspects, measuring is conducted at least, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, or 30 feet from the far-UV radiation source. For example, the far-UV radiation source and the ozone detector 140 can be placed in opposite ends of a space or they can be placed together.

[0062] The control module 130 receives measured ozone data from the ozone detector 140 for processing. Processing utilizes one or more of arithmetic, algorithms, machine learning models, statistical analysis, trend analysis, or other forms of data processing to identify the amount of ozone generated by the one or more far-UV radiation source 101, which is useful as a proxy measurement for the amount of far-UV irradiation provided by the one or more far-UV radiation source 101.

[0063] Processing the ozone measurement data permits one to identify the amount of ozone contributed from one or more far-UV radiation source 101 relative to measured ozone obtained from the space. In various aspects, processing the measured ozone value determines an amount of ozone produced due to irradiation from an individual far-UV source 101. Upon identifying the amount of ozone that is being generated by the far-UV radiation source, one can infer from first principles the amount of far-UV irradiation provided by the far-UV radiation source. For simple systems having consistent baseline ozone levels, the amount offar-UV irradiation can be readily determined by comparing measured ozone levels to baseline ozone levels. In more complex systems, various techniques can be used to account for multiple ozone sources, including computational, machine learning, statistical, and trend fitting methods. Parameters can include measured values, referenced values, or both. Parameters can represent environmental, circumstantial, and other variables related to the space, its use, or other one or more far-UV radiation source. Signal processing methods can be used to identify when a given generator (such as the far-UV radiation source 101) is active or dormant, and varying baseline and environmental factors can be accounted for.

[0064] A mass balance equation can be utilized when processing ozone data: ^^^^^ + ^^^^^^^^^^ = ^^^^^^ + ^^^^^^^^^^^^ +^^^^^^^^^^^ (1)

[0065] In various examples, processing can utilize a mass balance equation to solve for the portion of the generation term corresponding the amount of ozone generated by the far-UV radiation source, for example: ^^^^^^ + ^^^^^^^^^^^^ + ^^^^^^^^^^^ െ ^^^^^ െ (2)^^^^^^^^^^^௧^^^ ^^௨^^^^= ^^^^^^^^^^^^^ି^^ ^^ௗ^^௧^^^ ^^௨^^^

[0066] Processing can utilize determined ozone values, including: measured ozone values, prior-measured ozone values, reference values, expected values, or ozone profiles providing a collection of data showing how ozone changes with respect to the given far-UV radiation source or space. The control module 130 may access a database or memory unit containing such reference values or models. In various aspects, processing the measured ozone value comprises evaluating the measured ozone concentration relative to one or more ozone reference values. The one or more ozone reference values can include a baseline, a background, a cutoff limit, a lower bound target ozone level, an upper bound target ozone level, one or more ozone concentrations previously determined for air in the space, or any combination thereof. Processing can also consider state information about the far- UV radiation sources or system when measuring or determining ozone values. For example, measured ozone values can correspond to a measurement taken when each of the one or more far-UV radiation sources is turned on or off. Processingcan also utilize referenced, measured, or estimated parameters to inform the various output, consumption, input, and generation terms. For example, measured or reference values can be utilized to correct for ozone not corresponding to effective irradiation (e.g., ozone generated by electronics within the various components) to facilitate isolating the ozone generation term that corresponds to far-UV radiation. As another example, measured or reference values can be utilized to represent consumption terms related to ozone adsorption or degradation by materials or surfaces within the space. As yet another example, measured or reference values can be utilized to represent generation or consumption terms related to ozone changes due to ventilation or air purification. Processing models can also adjust for ozone mixing, chemical production, chemical loss, and physical loss. Various useful parameters and relationships are described in Poppendieck et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 675^679, a copy of which is incorporated by reference herewith in its entirety.

[0067] Because in various aspects, the method, apparatus, and system can be configured to target ozone content well below a cutoff limit, it is simply not possible for such systems to violate human safety limits for ozone. Further, various aspects of the method, apparatus, and system are configured to detect and be responsive to any current ozone amount in the deployed space, such method, apparatus, and system can advantageously respond to certain environments where higher or lower ozone amounts would be beneficial. Conventional designs do not adapt to changing ozone environments, techniques like ozone limits designed into the device may results in subpar performance due to radiation output that is too low in many circumstances, or they may result in inefficient design that emits more radiation than would be appropriate in other circumstances.

[0068] The baseline ozone reference value can represent an amount of ozone from ambient sources and non-ambient sources other than the far-UV radiation source. The background ozone reference value can represent an amount of ozone from ambient sources. The background ozone can be experimentally determined or determined from geolocated ozone data obtained from the Environmental Protection Agency (EPA) Air Quality System (AQS) database or AirNow database. The baseline, the background, or both, can account for daily, seasonal, or weather-related fluctuations of ozone in the space.

[0069] The cutoff limit can represent an exposure limit for ozone. The cutoff limit can be defined by the Occupational Safety and Health Administration (OSHA), National Institute for Occupational Safety & Health (NIOSH), Environmental Protection Agency (EPA), or American Conference of Governmental Industrial Hygienists (ACGIH). The cutoff limit is a maximum ozone concentration safe for an intended human use of the space. The cutoff limit can correspond to one or more of the following exposure limits: a) 100 ppb over an 8-hour period of intended human use of the space; b) 80 ppb over an 8-hour period of intended human use of the space; c) 70 ppb over an 8-hour period of intended human use of the space; d) 50 ppb over an 8-hour period of intended human use of the space; e) 300 ppb over a 15 minute period of intended human use of the space; or f) about 50 ppb, 60 ppb, 70 ppb, 80 ppb, 90 ppb, 100 ppb, 500 ppb, 1,000 ppb, 5,000 ppb or more.

[0070] Processing can also refer to various target values. Target values can be useful for controlling a far-UV radiation source to deliver a particular desired radiation output to the space. The desired radiation output can be described in terms of target far-UV irradiation, or as a target ozone value (e.g., concentration or rate) Target far-UV irradiation can refer to total far-UV irradiation levels provided by one or more far-UV radiation sources to the space, or it can refer to the contribution of a single far-UV radiation source. The presently described methods, systems, and apparatus can be useful for targeting a particular eACH level for the space based on a desired level of germicidal protection. For example, a high pathogen removal rate may be desired in a hospital setting (e.g., eACH of 9, 10, 11, or greater), an office may warrant a moderate level of protection (e.g., eACH of about 3, 4, 5, 6, 7, or 8), while a residence may warrant a lower level of protection (e.g., eACH of about 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or 2).

[0071] Minimum and maximum target values can be useful to permit safe variation in performance or environmental conditions. Minimum and maximum target values can also be useful for identifying when changes in ozone concentration can reflect a fault in device functioning, conditions which impede sufficient germicidal irradiation, or unsafe conditions. In various aspects, target values can be in units concentration, rate, flux, fluence, power, eACH, or the like. For example, monitoring ozone using minimum and maximum target values canalso be useful for identifying errors in a system having multiple far-UV radiation sources resulting in functioning below a specified eACH suitable for the designated space.

[0072] A lower bound target ozone level can be a minimum target ozone concentration or minimum target ozone generation rate for the space. The lower bound target ozone level can represent a minimum target far-UV irradiation level. The particular target values can be based on the desired amount of far-UV irradiation in the space. Different lower bound target ozone levels can be used depending on whether the lower bound target is provided in the context of total ozone concentration in the room, or a lower bound target for the amount of ozone individually provided by the far-UV radiation source. In various examples, the lower bound target ozone level is an ozone concentration of about 0.01 ppb, 0.05 ppb, 0.10 ppb, 0.15 ppb, 0.20 ppb, 0.25 ppb, 0.30 ppb, 0.35 ppb, 0.40 ppb, 0.45 ppb, 0.50 ppb, 0.55 ppb, 0.60 ppb, 0.65 ppb, 0.70 ppb, 0.75 ppb, 0.80 ppb, 0.85 ppb, 0.90 ppb, 0.95 ppb 1 ppb, 2 ppb, 3 ppb, 4 ppb, 5 ppb, 6 ppb, 7 ppb, 8 ppb, 9 ppb, 10 ppb, 11 ppb, 12 ppb, 13 ppb, 14 ppb, 15 ppb, 16 ppb, 17 ppb, 18 ppb, 19 ppb, or 20 ppb, or any range of values therein. In various examples, the lower bound target ozone level is an ozone concentration of about 0.01 ppb, 0.05 ppb, 0.10 ppb, 0.15 ppb, 0.20 ppb, 0.25 ppb, 0.30 ppb, 0.35 ppb, 0.40 ppb, 0.45 ppb, 0.50 ppb, 0.55 ppb, 0.60 ppb, 0.65 ppb, 0.70 ppb, 0.75 ppb, 0.80 ppb, 0.85 ppb, 0.90 ppb, 0.95 ppb 1 ppb, 2 ppb, 3 ppb, 4 ppb, 5 ppb, 6 ppb, 7 ppb, 8 ppb, 9 ppb, or about 10 ppb above baseline. In various examples, the lower bound target ozone level is an ozone concentration of about 0.01 ppb, 0.05 ppb, 0.10 ppb, 0.15 ppb, 0.20 ppb, 0.25 ppb, 0.30 ppb, 0.35 ppb, 0.40 ppb, 0.45 ppb, 0.50 ppb, 0.55 ppb, 0.60 ppb, 0.65 ppb, 0.70 ppb, 0.75 ppb, 0.80 ppb, 0.85 ppb, 0.90 ppb, 0.95 ppb 1 ppb, 2 ppb, 3 ppb, 4 ppb, 5 ppb, 6 ppb, 7 ppb, 8 ppb, 9 ppb, or about 10 ppb above background. Measurements of ozone concentration can correspond to a measurement at a particular point in time, or they can correspond to a measurement taken after ozone levels have reached a steady state based on the contributions from the one or more far-UV radiation source. An upper bound target ozone level can be a maximum target ozone concentration or maximum target ozone generation rate for the space. The upper bound target ozone level can represent a maximum target far-UV irradiation level. The particular target valuescan be based on the desired amount of far-UV irradiation in the space. Different upper bound target ozone levels can be used depending on whether the upper bound target is provided in the context of total ozone concentration in the room, or an upper bound target for the amount of ozone individually provided by the far- UV radiation source. The upper bound target ozone levels do not necessarily relate to any safety thresholds, but instead can correspond to target irradiation levels that are well within safety thresholds for ozone generation, radiation exposure, or both. In various examples, the lower bound target ozone level is an ozone concentration of about 10 ppb, 11 ppb, 12 ppb, 13 ppb, 14 ppb, 15 ppb, 16 ppb, 17 ppb, 18 ppb, 19 ppb, 20 ppb, 21 ppb, 22 ppb, 23 ppb, 24 ppb, 25 ppb, 26 ppb, 27 ppb, 28 ppb, 29 ppb, 30 ppb, 31 ppb, 32 ppb, 33 ppb, 34 ppb, 35 ppb, 36 ppb, 37 ppb, 38 ppb, 39 ppb, 40 ppb, 41 ppb, 42 ppb, 43 ppb, 44 ppb, 45 ppb, 46 ppb, 47 ppb, 48 ppb, 49 ppb, or about 50 ppb, or a range of any values therein, which can be determined for a given point in time or after permitting ozone in the air to reach a steady state. In various examples, the lower bound target ozone level is an ozone concentration of about 1 ppb, 2 ppb, 3 ppb, 4 ppb, 5 ppb, 6 ppb, 7 ppb, 8 ppb, 9 ppb, 10 ppb, 11 ppb, 12 ppb, 13 ppb, 14 ppb, 15 ppb, 16 ppb, 17 ppb, 18 ppb, 19 ppb, 20 ppb, 21 ppb, 22 ppb, 23 ppb, 24 ppb, 25 ppb, 26 ppb, 27 ppb, 28 ppb, 29 ppb, 30 ppb, 31 ppb, 32 ppb, 33 ppb, 34 ppb, 35 ppb, 36 ppb, 37 ppb, 38 ppb, 39 ppb, or about 40 ppb above baseline, or a range of any values therein. In various examples, the lower bound target ozone level is an ozone concentration of about 1 ppb, 2 ppb, 3 ppb, 4 ppb, 5 ppb, 6 ppb, 7 ppb, 8 ppb, 9 ppb, 10 ppb, 11 ppb, 12 ppb, 13 ppb, 14 ppb, 15 ppb, 16 ppb, 17 ppb, 18 ppb, 19 ppb, 20 ppb, 21 ppb, 22 ppb, 23 ppb, 24 ppb, 25 ppb, 26 ppb, 27 ppb, 28 ppb, 29 ppb, 30 ppb, 31 ppb, 32 ppb, 33 ppb, 34 ppb, 35 ppb, 36 ppb, 37 ppb, 38 ppb, 39 ppb, or about 40 ppb above background, or a range of any values therein. For example, one or more far-UV radiation sources can be adjusted based on targeting 0.5 ppb to 50 ppb, 0.5 ppb to 5 ppb, 1 ppb to 3 ppb, 1 ppb to 10 ppb, 2 ppb to 10 ppb, 5 ppb to 10 ppb, 5 ppb to 30 ppb, 10 ppb to 30 ppb, 15 ppb to 30 ppb, 20 ppb to 30 ppb, or 1 ppb to 30 ppb above baseline or above background. As another example, one or more far-UV radiation sources can be adjusted based on targeting 0.5 ppb to 50 ppb, 0.5 ppb to 5 ppb, 1 ppb to 3 ppb, 1 ppb to 10 ppb, 2 ppb to 10 ppb, 5 ppb to 10 ppb, 5 ppb to 30 ppb, 10 ppb to 30 ppb, 15 ppb to 30 ppb, 20 ppb to 30 ppb, or 1 ppb to 30 ppb over 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 20, or 24 hours. As another example, one or more far-UV radiation sources can be adjusted based on targeting 0.5 ppb to 50 ppb, 0.5 ppb to 5 ppb, 1 ppb to 3 ppb, 1 ppb to 10 ppb, 2 ppb to 10 ppb, 5 ppb to 10 ppb, 5 ppb to 30 ppb, 10 ppb to 30 ppb, 15 ppb to 30 ppb, 20 ppb to 30 ppb, or 1 ppb to 30 ppb, or a range of any values therein, as measured at a point of achieving a steady state contribution to ozone concentration. Measurements of ozone concentration can correspond to a measurement at a particular point in time, or they can correspond to a measurement taken after ozone levels have reached a steady state based on the contributions from the one or more far-UV radiation source.

[0073] Ozone reference values can also include one or more ozone concentrations previously measured from air in the space. Such values can be useful for comparing how ozone concentrations have changed over time. Ozone reference values can also include ozone generation rates. Processing the determined ozone value can include determining the rate of ozone generation due to irradiation from the far-UV source relative and then evaluating it relative to a lower bound target ozone generation rate, an upper bound target ozone generation rate, or both.

[0074] In various examples, the lower bound target ozone level is an ozone generation rate of 0.005 ppb / h, 0.01 ppb / h, 0.02 ppb / h, 0.03 ppb / h, 0.04 ppb / h, 0.05 ppb / h, 0.06 ppb / h, 0.07 ppb / h, 0.08 ppb / h, 0.09 ppb / h, 0.10 ppb / h, 0.15 ppb / h, 0.20 ppb / h, 0.25 ppb / h, 0.30 ppb / h, 0.35 ppb / h, 0.40 ppb / h, 0.45 ppb / h, 0.50 ppb / h, 0.55 ppb / h, 0.60 ppb / h, 0.65 ppb / h, 0.70 ppb / h, 0.75 ppb / h, 0.80 ppb / h, 0.85 ppb / h, 0.90 ppb / h, 0.95 ppb / h, 1 ppb / h, 2 ppb / h, 3 ppb / h, 4 ppb / h, 5 ppb / h, 6 ppb / h, 7 ppb / h, 8 ppb / h, 9 ppb / h, 10 ppb / h, 20 ppb / h, 30 ppb / h, 40 ppb / h, or 50 ppb / h, or a range of any values therein.

[0075] In various examples, the lower bound target ozone level is an ozone generation rate of about ^^XJ^^KÂZ^^^^^XJ^^KÂZ^^^^^XJ^^KÂZ^^^^^XJ^^KÂZ^^^^^XJ^^KÂZ^^^ ^^ XJ^^KÂZ^^^ ^^ XJ^^KÂZ^^^ ^^ XJ^^KÂZ^^^ ^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ or ^^^ XJ^^KÂZ^^ or a range of any values therein, based on electrical power (w) of the UV radiation source.

[0076] In various examples, the lower bound target ozone level can be an ozone generation rate of 0.001 mg / h, 0.002 mg / h, 0.003 mg / h, 0.004 mg / h, 0.005 mg / h, 0.006 mg / h, 0.007 mg / h, 0.008 mg / h, 0.009 mg / h, 0.01 mg / h, 0.02 mg / h, 0.03 mg / h, 0.04 mg / h, 0.05 mg / h, 0.06 mg / h, 0.07 mg / h, 0.08 mg / h, 0.09 mg / h, 0.01 mg / h, 0.05 mg / h, 0.1 mg / h, 0.2 mg / h, 0.3 mg / h, 0.4 mg / h, 0.5 mg / h, 0.6 mg / h, 0.7 mg / h, 0.8 mg / h, 0.9 mg / h, 1 mg / h, 2 mg / h, 3 mg / h, 4 mg / h, 5 mg / h, 6 mg / h, 7 mg / h, 8 mg / h, 9 mg / h, 10 mg / h, or a range of any values therein, per UV radiation source.

[0077] In various examples, the lower bound target ozone level can be an ozone generation rate of about 0.1 mJ^^KÂZ^^^ 0.5 mJ^^KÂZ^^^ 1 mJ^^KÂZ^^^ 2 mJ^^KÂZ^^^ 3 mJ^^KÂZ^^^ 4 mJ^^KÂZ^^^ 5 mJ^^KÂZ^^^ 6 mJ^^KÂZ^^^ 7 mJ^^KÂZ^^^ 8 mJ^^KÂZ), 9 mJ^^KÂZ^^^or 10 mJ^^KÂZ^, based on radiant flux (w) output of the UV radiation source.

[0078] In various examples, the upper bound target ozone level is an ozone generation rate of 0.50 ppb / h, 0.55 ppb / h, 0.60 ppb / h, 0.65 ppb / h, 0.70 ppb / h, 0.75 ppb / h, 0.80 ppb / h, 0.85 ppb / h, 0.90 ppb / h, 0.95 ppb / h, 1 ppb / h, 2 ppb / h, 3 ppb / h, 4 ppb / h, 5 ppb / h, 6 ppb / h, 7 ppb / h, 8 ppb / h, 9 ppb / h, 10 ppb / h, 11 ppb / h, 12 ppb / h, 13 ppb / h, 14 ppb / h, 15 ppb / h, 16 ppb / h, 17 ppb / h, 18 ppb / h, 19 ppb / h, 20 ppb / h, 21 ppb / h, 22 ppb / h, 23 ppb / h, 24 ppb / h, 25 ppb / h, 26 ppb / h, 27 ppb / h, 28 ppb / h, 29 ppb / h, 30 ppb / h, 31 ppb / h, 32 ppb / h, 33 ppb / h, 34 ppb / h, 35 ppb / h, 36 ppb / h, 37 ppb / h, 38 ppb / h, 39 ppb / h, 40 ppb / h, 41 ppb / h, 42 ppb / h, 43 ppb / h, 44 ppb / h, 45 ppb / h, 46 ppb / h, 47 ppb / h, 48 ppb / h, 49 ppb / h, 50 ppb / h, 60 ppb / h, 70 ppb / h, 80 ppb / h, 90 ppb / h, 100 ppb / h, 150 ppb / h, 200 ppb / h, 250 ppb / h, 300 ppb / h, 350 ppb / h, 400 ppb / h, 450 ppb / h, 500 ppb / h, or a range of any values therein.

[0079] In various examples, the upper bound target ozone level is an ozone generation rate of ^^XJ^^KÂZ^^^^^XJ^^KÂZ^^^^^XJ^^KÂZ^^^^^XJ^^KÂZ^^^^^XJ^^KÂZ^^^^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^ XJ^^KÂZ^^^ ^^^XJ^^KÂZ^^^^^^XJ^^KÂZ^^^^^^XJ^^KÂZ^^^^^^XJ^^KÂZ^^^or ^^^XJ^^KÂZ^^^EDVHG^RQ^HOHFWULFDO^ power (w) of the UV radiation source.

[0080] In various examples, the upper bound target ozone level can be an ozone generation rate of 1 mg / h, 2 mg / h, 3 mg / h, 4 mg / h, 5 mg / h, 6 mg / h, 7 mg / h, 8 mg / h, 9 mg / h, 10 mg / h, 20 mg / h, 30 mg / h, 40 mg / h, 50 mg / h, 60 mg / h, 70 mg / h, 80 mg / h, 90 mg / h, 100 mg / h, or a range of any values therein, per UV radiation source.

[0081] In various examples, the lower bound target ozone level can be an ozone generation rate of about 5 mJ^^KÂZ^^^6 mJ^^KÂZ^^^7 mJ^^KÂZ^^^8 mJ^^KÂZ^^^9 mJ^^KÂZ^^^10 mJ^^KÂZ^, 11 mJ^^KÂZ^, 12 mJ^^KÂZ^, 13 mJ^^KÂZ^, 14 mJ^^KÂZ^, 15 mJ^^KÂZ^, 20 mJ^^KÂZ^, or 25 mJ^^KÂZ^, based on radiant flux (w) output of the UV radiation source.

[0082] One or more far-UV radiation source can be configured based on measuring or determining ozone concentration to target irradiating the space with a total irradiance at a value from about 0.001 µW / cm2to about 60 µW / cm2at a distance of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 meters from the far-UV radiation source. The distance can correspond to the intended distance of occupants using the space. The total irradiance can be about or less than 0.1 µW / cm2, 0.5 µW / cm2, 1.0 µW / cm2, 1.5 µW / cm2, 2.0 µW / cm2, 2.5 µW / cm2, 3.0 µW / cm2, 3.5 µW / cm2, 4.0 µW / cm2, 4.5 µW / cm2, 5.0 µW / cm2, 5.5 µW / cm2, 6.0 µW / cm2, 6.5 µW / cm2, 7.0 µW / cm2, 7.5 µW / cm2, 8.0 µW / cm2, 8.5 µW / cm2, 9.0 µW / cm2, 9.5 µW / cm2, 10 µW / cm2, 11 µW / cm2, 12 µW / cm2, 13 µW / cm2, 14 µW / cm2, 15 µW / cm2, 16 µW / cm2, 17 µW / cm2, 18 µW / cm2, 19 µW / cm2, 20 µW / cm2, 21 µW / cm2, 22 µW / cm2, 23 µW / cm2, 24 µW / cm2, 25 µW / cm2, 26 µW / cm2, 27 µW / cm2, 28 µW / cm2, 29 µW / cm2, 30 µW / cm2, 31 µW / cm2, 32 µW / cm2, 33 µW / cm2, 34 µW / cm2, 35 µW / cm2, 36 µW / cm2, 37 µW / cm2, 38 µW / cm2, 39 µW / cm2, 40 µW / cm2, 41 µW / cm2, 42 µW / cm2, 43 µW / cm2, 44 µW / cm2, 45 µW / cm2, 46 µW / cm2, 47 µW / cm2, 48 µW / cm2, 49 µW / cm2, 50 µW / cm2, 51 µW / cm2, 52 µW / cm2, 53 µW / cm2, 54 µW / cm2, 55 µW / cm2, 56 µW / cm2, 57 µW / cm2, 58 µW / cm2, 59 µW / cm2, or 60 µW / cm2, or any range of values therein, at a distance of 1 meter from the far-UV radiation source or at a nearest distance between the far-UV radiation source and a location of an expected occupant. The total irradiance can be about or at least 0.001 µW / cm2, 0.002 µW / cm2, 0.003, µW / cm2,0.004 µW / cm2, 0.005 µW / cm2, 0.006 µW / cm2, 0.007 µW / cm2, 0.008 µW / cm2, 0.009 µW / cm2, 0.01, µW / cm2, 0.02 µW / cm2, 0.03, µW / cm2, 0.04 µW / cm2, 0.05 µW / cm2, 0.06 µW / cm2, 0.07 µW / cm2, 0.08 µW / cm2, 0.09 µW / cm2, 0.1 µW / cm2, 0.5 µW / cm2, 1.0 µW / cm2, 1.5 µW / cm2, 2.0 µW / cm2, 2.5 µW / cm2, 3.0 µW / cm2, 3.5 µW / cm2, 4.0 µW / cm2, 4.5 µW / cm2, 5.0 µW / cm2, 5.5 µW / cm2, 6.0 µW / cm2, 6.5 µW / cm2, 7.0 µW / cm2, 7.5 µW / cm2, 8.0 µW / cm2, 8.5 µW / cm2, 9.0 µW / cm2, 9.5 µW / cm2, 10 µW / cm2, 11 µW / cm2, 12 µW / cm2, 13 µW / cm2, 14 µW / cm2, 15 µW / cm2, 16 µW / cm2, 17 µW / cm2, 18 µW / cm2, 19 µW / cm2, or 20 µW / cm2, or any range of values therein, at a distance of 1 meter from the far-UV radiation source or at a nearest distance between the far-UV radiation source and a location of an expected occupant. In some aspects, the one or more far-UV radiation source can be configured to irradiate the space with 10 µW / cm2, 11 µW / cm2, 12 µW / cm2, 13 µW / cm2, 14 µW / cm2, or 15 µW / cm2at a distance of 1 meter from the far-UV radiation source or at a nearest distance between the far-UV radiation source and a location of an expected occupant. Total irradiance in the immediate vicinity of some far-UV radiation sources can be relatively high ^ 105 µW / cm2at 0 cm from the source and 27 µW / cm2at 5 cm from the source ^ but total irradiance drops very quickly with distance. See, Jimenez et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 668^674, which is incorporated by reference herewith. Total irradiance can be measured by utilizing ozone concentration as presently described herein, by using a photometer, spectrometer, or dosimeter, by utilizing chemical actinometry, or any combination thereof. One technique, such as a photometer, can be used to calibrate a subsequent technique, such as calculation from ozone concentration. Total irradiance can be measured by utilizing ozone concentration as presently described herein, by using a photometer, spectrometer, or dosimeter, by utilizing chemical actinometry, or any combination thereof. One technique, such as a photometer, can be used to calibrate a subsequent technique, such as calculation from ozone concentration.

[0083] One or more far-UV radiation source can be configured based on measuring or determining ozone concentration to target irradiating the space with a total optical power of about or less than 4 mW, 5 mW, 6 mW, 7 mW, 8 mW, 9 mW, 10 mW, 15 mW, 20 mW, 25 mW, 30 mW, 35 mW, 40 mW, 45 mW, 50 mW, 55 mW, 60 mW, 65 mW, 70 mW, 75 mW, 80 mW, 85 mW, 90 mW, 95 mW, 100mW, 105 mW, 110 mW, 115 mW, 120 mW, 125 mW, 130 mW, 135 mW, 140 mW, 145 mW, 150 mW, 155 mW, 160 mW, 165 mW, 170 mW, 175 mW, 180 mW, 185 mW, 190 mW, 195 mW, 200 mW, 205 mW, 210 mW, 215 mW, 220 mW, 225 mW, 230 mW, 235 mW, 240 mW, 245 mW, 250 mW, 255 mW, 260 mW, 265 mW, 270 mW, 275 mW, 280 mW, 285 mW, 290 mW, 295 mW, 300 mW, 305 mW, 310 mW, 315 mW, 320 mW, 325 mW, 330 mW, 335 mW, 340 mW, 345 mW, 350 mW, 355 mW, 360 mW 15 mW, 20 mW, 25 mW, 30 mW, 35 mW, 40 mW, 45 mW, 50 mW, 55 mW, 60 mW, 65 mW, 70 mW, 75 mW, 80 mW, 85 mW, 90 mW, 95 mW, 100 mW, 101 mW, 102 mW, 103 mW, 104 mW, 105 mW, 106 mW, 107 mW, 108 mW, 109 mW, 110 mW, 111 mW, 112 mW, 113 mW, 114 mW, 115 mW, 116 mW, 117 mW, 118 mW, 119 mW, 120 mW, 121 mW, 122 mW, 123 mW, 124 mW, 125 mW, 126 mW, 127 mW, 128 mW, 129 mW, 130 mW, 131 mW, 132 mW, 133 mW, 134 mW, 135 mW, 136 mW, 137 mW, 138 mW, 139 mW, 140 mW, 145 mW, 150 mW, 155 mW, 160 mW, 165 mW, 170 mW, 175 mW, 180 mW, 185 mW, 190 mW, 195 mW, 200 mW, 205 mW, 210 mW, 215mW, 225 mW, 230 mW, 235 mW, 240 mW, 245 mW, 250 mW, 255 mW, 260 mW, 265 mW, 270 mW, 275 mW, 280 mW, 285 mW, 290 mW, 295 mW, 300 mW, 305 mW, 310 mW, 315 mW, 320 mW, 325 mW, 330 mW, 335 mW, 340 mW, 345 mW, 350 mW, 355 mW, or 360 mW, or any range of values therein can represent a target minimum and maximum value. For example, the one or more far-UV radiation source can irradiate an occupiable space with a total optical power of 120 mW. Total optical power can be measured by utilizing ozone concentration as presently described herein, by using a photometer, spectrometer, or dosimeter, by utilizing chemical actinometry, or any combination thereof. One technique, such as a photometer, can be used to calibrate a subsequent technique, such as calculation from ozone concentration. One or more far-UV radiation source can be configured based on measuring or determining ozone concentration to target irradiating the space with a total optical power sufficient to inactivate Sars-CoV-2 virus in air. One or more far-UV radiation source can be configured based on measuring or determining ozone concentration to target irradiating the space with a total optical power sufficient to provide a germicidal efficacy of 99% or greater for Sars-CoV-2 virus in air.

[0084] Processing can also utilize non-ozone parameters. In various aspects, processing the determined ozone value comprises evaluating the determined ozone amount relative to one or more non-ozone parameters selected from the group consisting of temperature, humidity, time of day, date, season, location, elevation, ambient pressure, volatile organic compound (VOC) concentration, VOC molecular profile, CO2 concentration, PM2.5 concentration, PM10 concentration, PM0.1 concentration, air quality index (AQI), amount of windows in the space, amount of ventilation in the space, amount of air purification in the space, amount of air exchanges or effective air exchanges provided to the space, volume of space, surface area of space, type of materials in the space, weather, ceiling height, HVAC specifications, UV index, number of actual or intended occupants of the space, distance between occupants, type of actual or intended use of the space, current use status of space, power provided to far-UV radiation source, on-off status of far-UV radiation source, emission spectra of far-UV radiation source, model information and specifications of far- UV radiation source, details of any additional far-UV radiation sources in the space, details of any other ozone-generating devices in the space, density of occupants, distance between occupants, estimated transit times of infectious particles, and estimates of infection risk. For example, it can be useful to utilize parameters corresponding to occupancy as higher occupancy would suggest a need for a higher ozone target value, whereas a lower occupancy would suggest a need for a lower ozone target value ^ this approach is unintuitive given that the general approach has been to reduce ozone in the presence of occupants ^ yet the presence of ozone generation is advantageously used to determine the presence of germicidal UV. It has not been previously recognized that it is advantageous to utilize ozone content to obtain ozone-derived proxy measurements to inform and guide a UV irradiation process. Non-ozone parameters include parameters that are not irradiation parameters or parameters that describe amount of radiation output, which can be referred to as non-ozone, non-radiation parameters.

[0085] The emission spectra of the far-UV radiation source can be useful because some far-UV radiation sources may provide radiation having wavelengths with different coefficients for generating ozone. Indeed, some far-UV radiation sources may provide radiation having wavelengths that consume ozone or prevent generation of ozone. Also, the emission spectra of the far-UV radiation source can be useful because different wavelengths can have differing contribution to exposure limits, and thus can dictate the target irradiation in the space. For example, irradiation exposure weighted by wavelength can be calculated by measuring irradiance between 180-400nm weighted by a factor corresponding to potential damage to the eyes as derived from the ACGIH exposure limit curve for eyes or the IES exposure limit curve for eyes. Yet further, the emission spectra of the far-UV radiation source can be useful because different wavelengths can have differing contribution to germicidal efficacy. Parameters related to ventilation and windows can be useful because outdoor air can be a significant source of ozone. Ventilation can be quantified by monitoring the decay of CO2 after an injection from a compressed gas cylinder, for example with an Aranet4 sensor (SAFTehnika, Latvia). Parameters such as volume and air exchange can be useful as they can impact the steady state accumulation of ozone. Parameters such as materials and surface area of the space can be useful because ozone consumption due to absorption or reacting with surfaces can be a meaningful consumption parameter in a mass balance. VOC related parameters can be useful because different volatile compounds have differing interactions with ozone. Some VOC compounds represent a consumption term for ozone and different VOC compounds can have different consumption coefficients; as such it can be useful to separate out each such term from other consumption terms. Examples of different VOC compounds include monoterpenes, diterpenes, alkanes, (e.g., cycloalkanes), alkenes (e.g., alkene monoterpenes or cyclic alkenes), aldehydes, and other compounds. VOC molecule profile refers to the chemical constituents of VOC content.

[0086] Models related to determining ozone concentration and rates from far- UV irradiation have been described by various groups. See, e.g., Poppendieck et al., Environ. Sci. Technol. Lett.2023, 10, 8, 675^679; Jimenez et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 668^674; and Barber et al., ChemRxiv. Jul. 18, 2023, each of which are incorporated by reference in their entireties. Such models can be useful, at least in part, toward the opposite goal of determining far-UV irradiation from ozone values.

[0087] For example, Jimenez et al. described experimental measurements of ozone generation by a far-UV radiation source in an office setting at ^^^^^ƍ elevation in Boulder, CO, and discusses how deposition and ventilation rates can be incorporated into ozone models. In the Jimenez example, a test far-UV radiation source cycled in 3-hour intervals (3 hours on, 3 hours off) reached a steady state of 8-14 ppb, which represented an increase about 6.5 ppb over a baseline. Baseline varied by about 4 ppb due to variation in ventilation rates (0.62-0.96 h^-1) and ozone deposition rates (0.5-2.3 h^-1, average 0.78 h^-1). Ozone generation from the tested far-UV radiation source suggested an ozone generation rate of about 8.6 ppb / h. Jimenez reported that the theoretical ozone production rate for a far-UV lamp filtered to 222 nm at a total UV fluence rate of 2.3x1012photons cm-2s-1is ~22 ppb / h. Jimenez et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 668^674, a copy of which is incorporated by reference herewith in its entirety.

[0088] Other studies have identified relatively consistent consumption values for ozone in indoor spaces. See, C.J. Weschler, Ozone in Indoor Environments: Concentration and Chemistry, Indoor Air 2000; 10: 269-288, which is incorporated by reference herewith in its entirity. Indoor air ozone depends on factors including outdoor ozone concentration, air exchange rates, indoor emission rates, surface removal rates, and reactions between ozone and other chemicals in the air. Variations can be exhibit strong diurnal, hour to hour, day to day, and season to season variation. The use type of various spaces can also exhibit different ozone content, but interestingly, can exhibit consistent indoor / outdoor ozone content, surface removal rates, and content ranges in general. As such, a wide range of information about a given space can be useful to determine background and basline ozone content, as well as passive ozone consumption rates for the space. As such, any number of data sources can be utilized to configure a viable mass balance model for ozone content in a space. As a simple example, a conventional residental room with no forced air can be modeled at 2.9 kd(A / V) / h surface removal rate, and a UV source can be modeled as a sole source of ozone generation, thus readily configuring a mass balance model of ozone for solution upon determining steady state ozone amounts resulting from irradiation in a residential room.

[0089] Processed measurements can represent the amount of ozone generated by a far-UV irradiation source and can be used as a proxy measurement for representing far-UV irradiation output by that same source. The proxy measurement is useful in itself as a means to monitor a given device or irradiated space. Such measurements can be used to monitor a far-UV irradiation system to assure sufficient germicidal protection in a space. The measurements can also be used to identify periods of excess far-UV radiation. Such periods of excess or insufficiency can arise due to device error or due to changes in the space (e.g., crowded occupancy, changes in ventilation, changes in air volume, changes in use of the space).

[0090] Processed measurements can also be used to adjust the amount of far- UV radiation delivered to the space 110 from one or more far-UV radiation sources 101. For example, the control module 130 can adjust the intensity, duration, frequency, or other parameters of the far-UV radiation source 101 to maintain an appropriate level of far-UV irradiation in the space 110. Such adjustments can be used to correct the far-UV radiation source based on the space, position of the device, current conditions, or other aspect of a deployed germicidal system. The system can also be used for maintenance or to monitor device performance. Aging far-UV radiation sources may provide reduced far-UV irradiation and thus reduced ozone. The control module 130 can also regulate radiation output in real-time or near real-time; for example, it can be configured to monitor ozone and regulate radiation output continuously, in intervals, or daily.

[0091] Calibration can be performed at the time of initial installation of a far- UV radiation source in a space, or subsequently. Various approaches to calibration are possible. One approach to calibration involves obtaining an ozone profile for the space. The ozone profile can include information about the space, ozone concentration data over time, baseline ozone concentrations, and / or background ozone concentrations. A target ozone profile can include information about desired ozone concentrations or rates. The ozone profile can show how the space reacts to ozone generation. In various examples, an ozone profile can reflect how efficiently a space consumes ozone (e.g., into surfaces or by reaction with ambient airborne materials) and it can reflect how ozone levels change based on ozone generation or input. Next, the room is subjected to far-UV radiation from the oneor more far-UV radiation source 101 and then an irradiation response profile is obtained. The far-UV radiation source 101 can be calibrated based on reference to the ozone profile, the response profile, and optionally additional information regarding the space and / or far-UV radiation source 101. Other approaches to calibration are also possible using ozone data. For example, one or more reference values can be used instead of an ozone profile, and one or more determined ozone values can be used instead of a response profile. Next, the one or more far-UV radiation source 101 is adjusted based on the calibration reading. In various aspects, calibration involves adjusting the power supply 120 or driver 125 to change the amount or nature of power supplied to the far-UV radiation source and thus alter its output. In further aspects, calibration involves removing one or more far-UV radiation sources when calibration indicates to reduce the amount of far- UV radiation delivered to the space, or adding one or more far-UV radiation sources when calibration indicates to increase the amount of far-UV irradiation delivered to the space. As an example, installation and calibration of far-UV irradiation in a space can involve testing each of the one or more far-UV radiation sources individually to determine their respective contributions to ozone concentration and thus infer their contribution of far-UV irradiation. The radiation output of each of the one or more far-UV radiation sources can be individually adjusted or one or more far-UV radiation sources can be added or removed. Calibration can be performed retrospectively or prospectively relative to use of the space or germicidal treatment. In various aspects, calibration can be passively performed continuously or in determined intervals during operation without requiring user involvement. Calibration can also involve cycling the various UV radiation sources on or off to derive information about the space and performance of each individual UV radiation source.

[0092] Processed measurements can also be used for regulating one or more far-UV radiation sources for the purposes of efficiency, safety, or assuring efficacy. Adjustments to the output of a far-UV radiation source may be suitable when there are changes in the space or its air. Adjustments may also be prompted due to changes in performance of a far-UV radiation source, including device failures, obstructions, clutter, and human interactions with the device or its installation. As such, the presently described methods, systems, and apparatus canbe useful for monitoring, maintenance, compliance, or to permit the far-UV radiation source to adapt to its environment. In various aspects, regulating involves adjusting the power supply 120 or driver 125 to change the amount or nature of power supplied to the far-UV radiation source and, thus can alter its output. In further aspects, regulating involves reducing the amount of power supplied to the far-UV radiation source or turning off one or more far-UV radiation sources when regulating indicates to reduce the amount of far-UV radiation delivered to the space, or increasing the amount of power supplied to the far-UV radiation source or turn on one or more far-UV radiation sources when regulating indicates to increase the amount of far-UV irradiation delivered to the space. As an example, regulating a far-UV irradiation in a space can involve testing each of the one or more far-UV radiation sources individually to determine their respective contributions to ozone concentration and thus infer their contribution of far-UV irradiation. The radiation output of each of the one or more far-UV radiation sources can be individually adjusted or one or more far-UV radiation sources can be added, removed, or turned on or off. Regulation can be performed retrospectively or prospectively relative to use of the space or germicidal treatment. In various aspects, regulating the UV radiation source can be passively performed continuously or in determined intervals during operation without requiring user involvement. Regulating can also involve cycling the various UV radiation sources on or off to derive information about the space and performance of each individual UV radiation source

[0093] The control module 130 can be any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. The control module 130 can comprise a processor and a memory. The memory can store instructions or data structures (e.g., software) embodying any one or more of the methodologies or functions described herein. The processor can execute the instructions. The control module can be a hardware component, a software component, computer, a tablet device, a smart phone, a web appliance, or a network appliance, each of which may be a dedicated or multipurpose device specifically configured for processing ozone measurements to provide a proxy measurement for far-UV irradiation and / or conveying a control signal for modulating the same. The control module 130 can be communicatively coupledwith the far-UV radiation apparatus 100 and the ozone detector 140 by a wired connection, a wireless connection, or both. The control module 130 can also be communicatively coupled with one or more additional components, such as a remote processor, a remote memory, an I / O component, additional control modules, additional far-UV radiation sources, or additional ozone detectors. I / O components can include user interface components, communication components, and sensor components, among others. User interface components can include visual components (e.g., a light-emitting diode (LED) display), acoustic components (e.g., speakers), haptic components (e.g., a vibratory motor, resistance mechanisms), or other signal generators. The user interface components can also include alphanumeric input components (e.g., a keyboard), point-based input components (e.g., a mouse), tactile input components (e.g., a physical button, a touch screen that provides location and / or force of touches or touch gestures, or other tactile input components), audio input components (e.g., a microphone), and the like.

[0094] Sensor components can include, for example, one or cameras, illumination sensor components (e.g., photometer), temperature sensor components (e.g., one or more thermometers that detect ambient temperature), humidity sensor components, pressure sensor components (e.g., barometer), acoustic sensor components (e.g., one or more microphones that detect background noise), proximity sensor components (e.g., infrared sensors that detect nearby objects), other proximity sensors (e.g., utilizing carbon dioxide concentration), non-ozone gas sensors, condensation particle counters (CPCs), non-CPC sensors for detecting particles or pollutants in air, or other components that may provide indications, measurements, or signals corresponding to a surrounding physical environment. The position components include location sensor components (e.g., a Global Positioning System (GPS) receiver component), altitude sensor components (e.g., altimeters or barometers that detect air pressure from which altitude may be derived), orientation sensor components (e.g., magnetometers), and the like. Sensors can include sensors that monitor ventilation and air flow, such as open-close status, and on-off status of air handlers.

[0095] Instructions transmitted between the control module 130 and the far- UV radiation apparatus 100, far-UV radiation source 101, power supply 120, and / or driver 125 can be transmitted or received across wired or wireless connections. For example, the instructions can be transmitted or received over a network, using a transmission medium, via a network interface device (e.g., a network interface component) and using any one of several well-known transfer protocols (e.g., hypertext transfer protocol (HTTP)). Similarly, the instructions may be transmitted or received using a transmission medium via a coupling (e.g., a peer-to-peer coupling) to the devices. For example, the control module 130 can be in communication with the far-UV radiation apparatus 100 and / or ozone detector 140 via a wireless connection. A wireless connection may be established according to a wireless communication standard such as Bluetooth® (e.g. , Bluetooth® Low Energy) (BLE), Wi-Fi® (e.g., according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards), mobile communications standards such as relating to 4G / Long Term Evolution (LTE), or the IEEE 802.15.4 family of standards, as illustrative examples. The far-UV radiation apparatus 100, control module 130, and ozone detector 140, can each include a communication component. The communication components can include a network interface component to interface with a network. Communication components include wired communication components, wireless communication components, cellular communication components, Near Field Communication (NFC) components, Bluetooth®components (e.g., Bluetooth®Low Energy), Wi-Fi®components, and other communication components to provide communication via other modalities. In addition, a variety of information may be derived via the communication components, such as location via Internet Protocol (IP) geolocation, location via Wi-Fi® signal triangulation, or location via detecting an NFC beacon signal that may indicate a particular location. Examples of a network include an ad hoc network, an intranet, an extranet, a virtual private network (VPN), a local area network (LAN), a wireless LAN (WLAN), a wide area network (WAN), a wireless WAN (WWAN), a metropolitan area network (MAN), the Internet, a portion of the Internet, a portion of the Public Switched Telephone Network (PSTN), a plain old telephone service (POTS) network, a cellular telephone network, a wireless network, a Wi-Fi® network, another type of network, or a combination of two or more such networks.

[0096] FIG. 2 illustrates an example far-UV apparatus 100 having a far-UV radiation source 101, a control module 130, and ozone detector 140. The far-UV radiation source 101 can include a bulb 102, a reflector 103, and lens 104, which are contained within a lamp housing 105. The lamp housing 105 provides a cavity where the bulb 102 is secured and protected. The reflector 103 serves to reflect light away from the inside of the lamp housing out through the lens 104. In various aspects, the lens 104 can include an optical filter. The lens 104 can, but need not necessarily, magnify, focus, or disperse light. The far-UV radiation source 101 emits radiation that is useful for germicidal treatment of air in a space. In yet further aspects, the far-UV apparatus 100 illustrated in FIG. 2 can be configured to implement the system of FIG. 1 into an apparatus. In some aspects, the far-UV apparatus 100 contains a far UV radiation source 101 and an ozone detection unit 140, and interacts with a control module 130 that is remote. In other aspects, the far-UV apparatus 100 contains a far UV radiation source 101, a control module 130, and a remote ozone detection unit 140 in a single device.

[0097] An ozone detection unit 140 provides a housing 111, and space for an ozone detector 145. The ozone detection unit can supply a means for determining the effective irradiation of the space by using ozone concentration as a proxy measurement. The ozone detection unit has one or more air intake 113, optionally containing one or more fans 115 or other means of capturing air from the space to provide it to the ozone detector. The ozone detector 145 can be any suitable module for detecting ozone, such as a UV absorption-based ozone monitor. One example of a suitable ozone detector is a 2B technologies Model 205 available from 2B Technologies (Boulder, CO). The ozone detection unit 140 and the far- UV radiation source 101 can be located within compartments in the same housing, or share the same support such as a stand, wall mount, or ceiling mount. The ozone detection unit 140 and the far-UV radiation source 101 can share a power source. As yet another example, the apparatus can comprise a first far-UV radiation source 101 and a second radiation source that is other than far-UV radiation, such as visible light.

[0098] The control module 130 can located within the housing of the apparatus or it may be remotely located. The control module 130 is configured to process data from the ozone detector 140 using one or more of arithmetic, algorithms, machine learning models, statistical analysis, trend analysis, and other forms of data processing to compare the determined ozone amount to reference values, expected values, or profiles, The control module 130 may access a local or remote database or memory unit containing such reference values or models. The control module 130 includes a processor, a memory, and can be any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Using the processed data, the control module 130 can regulate the intensity, duration, frequency, or other parameters of the far-UV radiation source 101 to control the level of emitted far-UV irradiation. In various aspects, the control module 130 receives a signal from the ozone detector 145 corresponding to a determined (e.g., measured) ozone concentration or change in ozone concentration. The control module 130 processes the received signal to identify the contribution from the far-UV radiation source 101 with respect to the total measured ozone. The amount of ozone generated by the far-UV radiation source 101 provides a proxy measurement which is useful for monitoring or controlling the far-UV radiation source 101. To control the far-UV radiation source 101, the control module 130 sends a signal to a power management module 118 to adjust performance of a driver 125. The driver 125 delivers power from the power supply 120 and modulates it to manage output from the far-UV radiation source 101. The far-UV apparatus 100 can be mounted on a stand 129 to provide convenient set up and for orienting and elevating the lamp to position to either maximize or minimize areas of direct irradiation, depending on use case. A stand can facilitate portability and placement of the device so that it does not disrupt the intended use of the space being treated. Optionally, the far-UV apparatus can include an air filtration system, which can include one or more mechanical filter and / or one or more scrubber. The scrubber can be an ozone scrubber. The ozone scrubber may be integrated together with one or more of the ozone detector 140, control module 130, or far-UV apparatus 100.

[0099] FIG.3 illustrates an example method 300 of assessing far-UV radiation in a space 110. The space 110 is furnished with one or more far-UV radiationsources 101, which are useful for inactivating pathogens in air. The method 300 involves a step 301 of measuring ozone concentration in air of the space 110. Measuring ozone concentration can be performed by using an ozone detector 140. The method 300 further involves a step 302 of evaluating the determined ozone concentration relative to one or more ozone concentration reference values to obtain a proxy measurement of far-UV irradiation in the treated space. The proxy measurement of far-UV irradiation of the air in the space can be useful for determining if the irradiation provided by the one or more far-UV radiation sources 101 is sufficient for inactivating pathogens. It can also be useful for determining if excessive irradiation is being provided by the one or more far-UV radiation sources 101.The method illustrated in FIG. 3 can be further utilized in methods of regulating far-UV radiation sources, calibrating far-UV radiation sources, or other methods for improving the efficiency and safety of far-UV radiation sources. The method illustrated in FIG. 3 can be implemented using an apparatus or system according to FIG.1 and FIG.2. In various aspects, the method illustrated in FIG. 3 can utilize a specifically configured machine or software process to perform one or more step of the method.

[0100] FIG.4 illustrates an example method 400 of regulating radiation output from one or more far-UV radiation source 101. The one or more far-UV radiation source 101 are configured for irradiating a space 110 to inactivate pathogens in air. The method 400 involves a step 401 of irradiating air of the space 110 with radiation from the one or more far-UV radiation sources 101. The one or more far- UV radiation source 101 provide radiation comprising one or more wavelengths of about 200 nm to about 230 nm. In various examples, the one or more far-UV radiation source 101 provides radiation comprising a wavelength of about 222 nm, which may be the peak wavelength of the emitted radiation. The method 400 further involves step 402 of measuring ozone concentration in air of the space 110. Measuring ozone concentration can be performed by using an ozone detector 140. Next, the method 400 involves a step 403 of evaluating the determined ozone concentration against one or more ozone concentration reference values to obtain a proxy measurement of effective far-UV irradiation. Step 404 utilizes the proxy measurement to adjust radiation output from the one or more far-UV radiation sources 101. The method illustrated in FIG. 4 can be further utilized in methodsfor improving the efficiency and safety of far-UV radiation sources. The method illustrated in FIG. 4 can be implemented using an apparatus or system according to FIG.1 and FIG.2. In various aspects, the method illustrated in FIG.4 can utilize a specifically configured machine or software process to perform one or more step of the method.

[0101] FIG. 5 illustrates an example method 500 of calibrating a far-UV radiation source 101 for a space 110. The method involves a step 501 of obtaining a baseline ozone profile, a target ozone profile, or both, each comprising one or more ozone concentration reference values. The baseline ozone profile can represent the presence and contribution of ozone from background sources and sources other than the far-UV radiation source 101 that is being calibrated. The target ozone profile can be a predetermined ozone profile based on expected output of the far-UV radiation source 101, or the expected combined output of the far-UV radiation source 101 together with background ozone sources and sources other than the far-UV radiation source 101. The method 500 can further involve a step 502 of measuring ozone concentration in air of the space while operating the far-UV radiation source to obtain an ozone response. Measuring ozone concentration can be performed by using an ozone detector 140. Measuring to obtain an ozone response can be performed as an impulse response, a continuous measurement, a step measurement, other techniques for measuring the contribution to ozone concentration from the radiation output of the tested far-UV radiation source 101. The method 500 can further involve a step 503 of evaluating the ozone response against the baseline ozone profile, the target ozone profile, or both, to obtain a proxy measurement of effective far-UV irradiation. Step 504 utilizes the proxy measurement to adjust radiation output from the one or more far-UV radiation sources 101. The method illustrated in FIG. 5 can be further utilized in methods for improving the efficiency and safety of far-UV radiation sources. The method illustrated in FIG. 5 can be implemented using an apparatus or system according to FIG.1 and FIG.2. In various aspects, the method illustrated in FIG. 5 can utilize a specifically configured machine or software process to perform one or more step of the method.

[0102] FIG.6 illustrates a block diagram of an example comprising a machine 600 through which one or more of the presently described methods can beperformed. The disclosure provides a machine 600 specifically adapted for utilizing ozone as a proxy measurement for determining far-UV irradiation. The machine 600 may be included as a portion of elements shown in the system of FIG.1, such as the far-UV radiation apparatus 100, the control module 130, or the ozone detector 140. In various examples, the machine 600 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine 600 may operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the machine 600 may act as a peer machine in peer-to-peer (P2P) (or other distributed) network environment. The machine 600 may be a personal computer (PC), a tablet device, a personal digital assistant (PDA), a mobile telephone, a web appliance, a network router, switch or bridge, a portable (e.g., hand-held) spectrometer such as including a microprocessor or microcontroller, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single machine is illustrated, the term ^machine^ shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations.

[0103] Machine (e.g., computer system) 600 may include a hardware processor 602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 604 and a static memory 606, some or all of which may communicate with each other via an interlink (e.g., bus) 630. The machine 600 may further include a display device 610, an alphanumeric input device 612 (e.g., a keyboard), and a user interface (UI) navigation device 614 (e.g., a mouse). In an example, the display unit 610, input device 612 and UI navigation device 614 may be a touch screen display. The machine 600 may additionally include a storage device (e.g., drive unit) 614, a signal generation device 618 (e.g., a speaker), a network interface device 620, and one or more sensors 616, such as a global positioning system (GPS) sensor, a thermometer, or humidity sensor. The machine 600 may include an output controller 628, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR)) connection to communicateor control one or more peripheral devices. The storage device 624 may include a machine-readable medium on which is stored one or more sets of data structures or instructions 624 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 624 may also reside, completely or at least partially, within the main memory 604, within static memory 606, or within the hardware processor 602 during execution thereof by the machine 600. In an example, one or any combination of the hardware processor 602, the main memory 604, the static memory 606, or the storage device 616 may constitute machine readable media. While the machine readable medium 622 is illustrated as a single medium, the term "machine readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) configured to store the one or more instructions 624. The term ^machine readable medium^ may include any medium that is capable of storing, encoding, or carrying instructions for execution by the machine 600 and that cause the machine 600 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine-readable medium examples may include solid-state memories, and optical and magnetic media. Accordingly, machine-readable media are not transitory propagating signals. Specific examples of massed machine-readable media may include: non-volatile memory, such as semiconductor memory devices and flash memory devices; magnetic or other phase-change or state-change memory circuits; and magnetic disks.

[0104] The instructions 624 may further be transmitted or received over a communications network 626 using a transmission medium via the network interface device 620 utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks such as conforming to one or more standards such as a 4G standard or Long Term Evolution (LTE)), Plain Old Telephone (POTS) networks, and wireless data networks (e.g., Institute of Electrical andElectronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.15.4 family of standards, peer-to-peer (P2P) networks, among others. In an example, the network interface device 620 may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network 626. In an example, the network interface device 620 may include a plurality of antennas to wirelessly communicate using at least one of single input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. The term ^transmission medium^ shall be taken to include any intangible medium that is capable of storing, encoding or carrying instructions for execution by the machine 600, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

[0105] FIG. 7 provides a plot illustrating changes in ozone concentration in a space over time and in relation to performance of a far-UV radiation source. Ozone concentration 701 generally follows a diurnal cycle during which background levels of ozone vary throughout the day. A daily minimum ozone concentration 702 is typically observed at night and a daily maximum ozone concentration 703 is typically observed during daylight hours. The daily minimum ozone concentration 702 and daily maximum ozone concentration 703 together represent baseline ozone concentration, which typically varies over time. Ozone can be generated when irradiating the space with a far-UV radiation source. When a far-UV radiation source is turned on, there is an increase in ozone concentration 704 that can be analyzed to determine the amount of radiation that a far-UV radiation source is providing to the space. The rate of change, or slope, 705 at various points following initial excess ozone generation can also be used to determine the amount of far-UV irradiation provided by the far-UV radiation source. A steady state ozone concentration 706 is ultimately achieved, which can sometimes coincide with the daily maximum ozone concentration 703. The steady state ozone concentration 706 can also be used to determine the amount of radiation that is provided by a far-UV radiation source. Various other approaches, e.g., integration, can be used to determine the amount of excess ozone corresponding to a given far-UV radiation source and, correspondingly, the amount of radiation it provides. In various examples, theexcess ozone can be evaluated relative to a baseline ozone 707, which can be observed in the absence of a far-UV radiation source, calculated, or predicted based on previously measured values or reference values. In many germicidal applications, it can be desirable to control the amount of far-UV radiation that is provided to the space. As illustrated in FIG. 7, dotted lines illustrate a window corresponding to achieving a target amount of far-UV irradiation, as well as the ozone concentration resulting therefrom. When a device is turned on with ideal far-UV output, the resulting excess ozone generated will fall within ranges that can be specified as target ozone values. In one example, an ideal functioning device will result in a steady state ozone concentration 706 that falls within a defined target range for steady state ozone. Similarly, the ideal functioning device will also meet defined target ranges for various increases in ozone concentration 704 and or rate of change of ozone concentration 705 following device activation. A malfunctioning device that produces no irradiation will show no excess ozone concentration 708. A device that warrants calibration or adjustment may provide an amount of far-UV radiation and ozone that is outside of target ranges. For example, a device that provides too little far-UV radiation to the space can result in an insufficient ozone concentration. Insufficient far-UV radiation can be reflected in ozone concentration changes 705 that are too little or too slow, or a resulting steady state ozone concentration 709 that is too low. A device that provides too much far-UV radiation to the space can result in an ozone concentration above target levels. Excessive far-UV radiation can be reflected in ozone concentration changes 705 that are too great or too fast, or a resulting steady state ozone concentration 710 that is too high.

[0106] FIG. 8 provides a plot of ozone concentration 801 over time for a space equipped with a far-UV radiation source. The data show how readily outlier ozone concentrations can be identified. Here, one can readily identify that a far-UV germicidal lamp was turned on at 804, which provided a sudden increase in ozone concentration. Ultimately, the generated ozone reaches a target irradiation 805, which is mostly within the target irradiation range. The target irradiation range can be calculated, estimated, empirically determined, or determined from calibration from prior known values. The plotted data also show that ozone follows a diurnal pattern, having low points 806 resulting fromsteady state generation and consumption of ozone during the daily minima. However, once the light is activated, the target irradiation 805 is quickly established by steady state balancing of generation and consumption terms. Diurnal and environment-based effects on ozone concentration can continue over the course of irradiation. Processing of the ozone concentration signal can involve a machine learning process, a predetermined rule-based process, or both. In some systems, such as the one shown in FIG. 8, the ozone contribution from the far-UV radiation source is readily identified, even at single-digit ppb amounts. In more complex systems, one can incorporate various other parameters including temperature, humidity, time of day, date, season, location, elevation, ambient pressure, volatile organic compound (VOC) concentration, VOC molecular profile, CO2 concentration, PM2.5 concentration, PM10 concentration, PM0.1 concentration, air quality index (AQI), amount of windows in the space, amount of ventilation in the space, amount of air purification in the space, amount of air exchanges or effective air exchanges provided to the space, volume of space, surface area of space, type of materials in the space, ceiling height, weather, UV index, number of actual or intended occupants of the space, HVAC specifications, type of actual or intended use of the space, current use status of space, power provided to far-UV radiation source, on-off status of far-UV radiation source, emission spectra of far-UV radiation source, model information and specifications of far-UV radiation source, details of any additional far-UV radiation sources in the space, and details of any other ozone-generating devices in the space. Calibration of the far- UV radiation source 101 with respect to ozone concentration can be achieved by measuring or reference to a known device having the desired performance properties or by experimentally determining target ozone concentrations. As another example, ozone concentrations measured when the device is on or off can be used to calibrate the device. Yet further, machine learning techniques can be utilized to identify sufficient or deviant functioning of a far-UV radiation source based on reference to prior or known performance.

[0107] FIG. 9 provides another set of data illustrating the effects of ozone concentration (ppb) in a human-use space. The data illustrates significant ppb fluctuations (~3 ppb) on a day-night cycle and (~2 ppb) relative differences whena far-UV radiation system is on or off. The effect of weather on baseline is further illustrated. The data also shows that the effect of multiple far-UV radiation sources is reflected from the data. The effect of each source can be isolated and analyzed individually or the sources can be analyzed in concert. The data also illustrates how ozone generation rates change based on the presence and absence of a far- UV radiation source.

[0108] FIG. 10A and 10B provide a diagram summarizing various examples of how ozone measurements can be used to assess irradiance, radiant flux, radiant exposure, germicidal efficacy, and eACH, and do so with the advantage of reflecting the effective action of far-UV light upon the treated air. Ozone measurements can be directly obtained 1010, for example via use of an ozone detector, or they can be indirectly obtained 1040 via use of a calibration value 1030. The calibration value can have various forms, including ozone amount per irradiance, ozone amount per radiant flux, ozone amount per radiant exposure, ozone amount per power utilized by radiation source, ozone amount per power supplied to radiation source, ozone amount per time of radiation source operation, ozone amount per area irradiated, ozone amount per area irradiated by distance, and the like. Calibration values are typically determined via prior measurement of ozone generation while operating the same device or an equivalent device. By using the calibration value, it is possible to accurately determine ozone amount (for example ozone generation rate, ozone concentration in a space, ozone mass, ozone particle count, etc) by applying the calibration value based on operating the device and information about the space being treated, thus obviating the need for ozone detection device during deployment, and yet still enjoying the advantages that arise from using ozone amounts to evaluate effective radiation output. Calibration values are not necessarily a single value; a calibration value can include multiple values, functions, or a data table. For example, a calibration value can include an ozone amount per area cross section at various distances from the source along the axis of its radiation pattern (i.e., the shape of the light emitted, which is typically a cone, frustrum, or beam). Due to the inverse square relationship of ozone generation per radiation output, the cross section closest to the source will produce more ozone than further cross sections. Thus, one approach to a calibration value is to store a first ozone generation rate for the firstcross section from zero to 1 foot from the source, a second ozone generation rate for the next cross section from 1 foot to 2 feet from the source, etc. Then, during operation of the device, a distance finder can be used to determine how far the generated radiation is transmitted through air (which contains the precursor for ozone generation) before encountering a wall. Ozone amounts can be determined thus with the calibration value and data describing the space in which the device is deployed. Another alternative includes user input of details of the space in which the device is deployed. As yet another option, the device can be identified for use in a particular size space or otherwise used in a manner in which the amount of irradiated space is predetermined. For example, a device configured for use in residential rooms, offices, work spaces, airports, class rooms, public transport spaces, hospital spaces, medical offices, operating rooms, can predictably approximate based on average or typical sizes of the target space (e.g., 12'x12', 10'x12', 10'x14', 14'x14', 10'x16' , 20'x20', etc). As further options, data can be collected from other sensors to determine room size or amount of air irradiated, such sensors can include modules utilizing mmWave, LIDAR, radar, time of flight distance measurement, ultrasonic range finding, monitoring and analysis of air or components therein to derive room volume or dimensions, or any combination thereof. Ozone amounts can be indirectly determined using operational parameters of the lamp (e.g., its power, size, and status) and size details of the irradiated space (e.g., room where device is deployed, size of space being irradiated). Many of these details can be measured or devices can be designated for particular uses cases or with instructions that resolve unknowns. For example, devices can include instructions to orient the radiation source so it has a clear path of irradiance out from the source of at least 10 feet. Due to the inverse square relationship of ozone generation and radiation output, the area closest to the radiation source is responsible for most of the ozone generated during deployment while the areas furthest from the source produce the least amounts of ozone, and in some cases the amount may not be significant with respect to target precision of ozone calculation.

[0109] FIG. 11 illustrates an example of a system including a UV radiation source 101 and a control module 130, which utilizes non-ozone parameter data together with a calibration value to determine ozone content in air of a space 110.The system is useful for assessing, measuring, calibrating, or controlling UV irradiation, exemplified as a non-limiting example of using a far-UV radiation to treat air in a human-occupied space. In various aspects, the system is configured to adjust radiation output of the UV radiation source 101. The system illustrated in FIG. 11 does not require directly measuring ozone content with an ozone detector. Rather, the system utilizes can utilize a calibration value together with one or more non-ozone parameter reflecting the state of the far-UV radiation source and space in which the device is deployed.

[0110] The calibration value is determined by: measuring ozone concentration in air of a test space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof. As a result, the calibration value can reflect a relationship between ozone and radiation output. In various alternatives, the calibration value can be based on ozone amount relative to lamp power, supplied power, watt-hours, fluence, radiant flux, irradiance, radiant exposure, and any other parameter of lamp operation, which can be calculated, measured, estimated, known or theoretical values. The calibration value elucidates the uncertainty between the expected output of a UV radiation source versus the actual way that UV radiation acts upon particles in the treated air. The calibration value is not necessarily a single value; the term calibration value can include a single value, multiple values, tables or organized data, functions, or take the form of complex calibration software. The purpose of a calibration value is to provide way to leverage empirically determined ozone generation data for understanding how the apparatus acts upon spaces. Typically a calibration value is previously determined at the manufacturing, design, quality control, safety control, or audit stages via testing of the actual device or a representative equivalent device. The calibration value can be incorporated into the device hardware or software.

[0111] Various aspects of air irradiation make the process difficult to model or predict, partially because particles move throughout the space, they come and go through the radiation pattern, and interact with themselves and other particles. Germicidal UV light can encounter various obstructions on its journey to destroy pathogens. Some ordinary contaminants in air can block or adsorb radiationoutput, as can other obstructions in the space or debris upon the UV source itself. Improper configuration of a UV source in a room can result in the UV source directly facing into a wall or obstacle, where there are fewer opportunities to irradiate particles. Conversely, positioning a UV radiation source facing a far opposing wall may result in any number of obstacles, occupants, shielding contaminants, and movement of particles, along the light path. While larger irradiation patterns can lead to larger amounts of germicidal disinfection, it also leads to greater inaccuracy if relying on photometric tools or ab initio calculation based on power supplied and device configuration. Such elements can result in reducing the amount of effective output radiation, when considered in a germicidal efficacy concept. The germicidal light models suffer from this same issue; they typically do not account for and use that information to achieve higher accuracy than would be possible by merely relying on the relationship between supplied power, fluence, and radiation pattern.

[0112] Example non-ozone parameter data useful in conjunction with calibration value include data from one or more sensor 150; user, computer, or technician input data from a user input device 160; data associated with ozone- removing or ozone-generating activity from other devices 170, such as an ozone scrubber or another UV radiation source; and data associated with activity from an air-handler, air exchanger, HVAC system, or ventilation source 180. Such data can be useful for determining ozone amounts in the space, deriving proxy measurements of radiation output, identifying target values, adjusting or governing operation of the UV radiation source or other component; and calibrating the UV radiation source based on determined ozone amount.

[0113] Various types of sensors 150 can be useful in the presently described system, including, but are not limited to, one or more: cameras, illumination sensor components (e.g., photometer), temperature sensor components (e.g., one or more thermometers that detect ambient temperature), humidity sensor components, pressure sensor components (e.g., barometer), acoustic sensor components (e.g., one or more microphones that detect background noise), proximity sensor components (e.g., infrared sensors that detect nearby objects), other proximity sensors (e.g., utilizing carbon dioxide concentration), non-ozone gas sensors, condensation particle counters (CPCs), non-CPC sensors fordetecting particles or pollutants in air, or other components that may provide indications, measurements, or signals corresponding to a surrounding physical environment. The position components include location sensor components (e.g., a Global Positioning System (GPS) receiver component), altitude sensor components (e.g., altimeters or barometers that detect air pressure from which altitude may be derived), orientation sensor components (e.g., magnetometers), and the like. Sensors can include sensors that monitor ventilation and air flow, such as open-close status, and on-off status of air handlers. Sensors can also include mmWave, LIDAR, radar, time of flight distance measurement, ultrasonic range finding, monitoring and analysis of air or components therein to derive information about a space where the device is deployed, such as the volume of the space, volume of the irradiated air, various dimensions, orientation of the space or irradiated air, shape of the space or irradiated air, various relative distances with respect to the UV source, various relative orientations with respect to the UV source, contents of the space, occupants, amount of clutter, amount of obstructions, amount of open space, or any combination of such data as it concerns ozone content, concentration values, consumption or generation values, and the like.

[0114] In various aspects, the system can interact with one or more sensor 150 that may be utilized to detect space (e.g., room) information, amount of air being irradiated, distance to nearest obstruction, distance to walls, distance to nearest occupant, area of irradiation, occupant information, occupant number, occupant activity, space use or purpose, increased or decreased germicidal efficacy, as well as any of the various other parameters described herein. Using the example of a range finder as an example, the sensor 150 can detect the size of the space being irradiated based on distance to a opposing wall, or distance until obstruction along the edges of the radiation pattern provided by the device. Once distance is identified, volume of irradiated air can be inferred or calculated based on the known radiation pattern provided by the radiation source. Range finder and other sensors utilizing LIDAR and mmWave, can also be used to determine dimension of the room in which the device is deployed. Obtaining these types of data from sensors can be useful for determining volume for determining concentrationvalues, but also useful for identifying how to accurately determine ozone generation when utilizing calibration values.

[0115] The system can also interact with a computer or user input 160 which may be utilized to input space (e.g., room) information, occupant information, occupant number, occupant activity, space use or purpose, increased or decreased germicidal efficacy, as well as other parameters described herein. Using desired germicidal efficacy, as an example, such information would not necessarily modify the amount of ozone determined for the space, but the information may be usefully applied to determine a suitable target ozone value: higher ozone target values can reflect higher germicidal efficacy, while lower ozone target values can reflect lower germicidal efficacy. As another example, room information can be especially useful for determining ozone content accurately. During deployment of the germicidal UV system or device, a user can indicate details about the space in which the device is deployed. This information can be stored locally in the apparatus 100, or remotely, and referenced to determine ozone content in the room together with a calibration value. In various aspects, the user or person deploying the device can input room details while the manufacturer of the device inputs a calibration value derived from testing the unit or a similar equivalent unit in a test space. In another aspect, deployment of the device can involve automatically or manually capturing room details, and also running a calibration sequence to obtain a calibration value from the actual space in which the device is being deployed. As discussed above, a calibration value can be obtained by irradiating a given space and determining ozone amount based on one or more unit of measurement describing device operation (e.g., time, power, etc). In other examples, the device can capture details about occupancy, either as user unput 160 or via a sensor 150. In some aspects, increased occupants may reflect a desire for greater germicidal efficacy, and thus a greater target ozone level. In other aspects, it may be desired to employ or increase germicidal efforts while spaces are unoccupied and turn off or decrease germicidal efforts when spaces are occupied. These examples of dynamic or adaptive interactions reflect advantages demonstrated by various examples of the present disclosure.

[0116] As another example, a sensor monitoring ventilation 180 may indicate that air is being exchanged in the space. As fresh air is brought into the space andirradiated air containing ozone is removed from the space, a resulting determination of ozone content may suggest that radiation output is insufficient and should be increased; indeed, fewer particles in air are being irradiated, or greater number of non-irradiated particles are being introduced into the space, thus reflecting a lower effective irradiance of the space. This dynamic interaction also reflects an advantage demonstrated by various examples of the present disclosure.

[0117] As yet another example, the system can also interact with other devices 170, such as another air purifier, UV radiation source, or ozone scrubber, in order to reflect that increased output from the radiation source is warranted to achieve a desired level of effective radiation or germicidal efficacy. In the example of using a scrubber; ozone, ozone precursors, or other particles can be removed from the air of the space, and thus the action of the UV radiation source can lead to a lower resulting ozone amount in the space. Subsequent determination of ozone amount and the resulting proxy measurement may thus suggest that radiation output can be increased. This dynamic interaction reflects yet another advantage demonstrated by various examples of the present disclosure. In various further embodiments, data associated with other devices, such as an air purifier, UV radiation source, or ozone scrubber can be utilized to assist in determining amount of ozone contribution provided by the UV source, or such data can assist in adjusting the target ozone levels to account for air exchanges or ozone removal via scrubbing.

[0118] The various aspects and discussions provided with respect to the system of FIG.1, apparatus of FIG.2, and methods illustrated in FIGS.3, 4, 5, 13, 14, and 15, and the relationships in FIG. 10 can also applying, including in their various combinations and permutations, to the system of FIG. 11.

[0119] FIG.12 illustrates an example calibrated far-UV apparatus 100 having a far-UV radiation source 101, a control module 130, which utilize non-ozone parameter data together with a calibration value to determine ozone content in air of a space without requiring direct measurement of the ozone content. The control module includes a hardware or software component that incorporates the calibration value so as to be configured for indirectly determining the amount ozone generated during use of the device.

[0120] The far-UV radiation source 101 can include a bulb 102, a reflector 103, and lens 104, which are contained within a lamp housing 105. The lamp housing 105 provides a cavity where the bulb 102 is secured and protected. The reflector 103 serves to reflect light away from the inside of the lamp housing out through the lens 104. In various aspects, the lens 104 can include an optical filter. The lens 104 can, but need not necessarily, magnify, focus, or disperse light. The far-UV radiation source 101 emits radiation that is useful for germicidal treatment of air in a space. In yet further aspects, the far-UV apparatus 100 illustrated in FIG. 12 can be configured to implement the system of FIG. 11 into an apparatus and configured to implement the various methods described herein.

[0121] The apparatus 100 utilizes a calibration value for indirectly determining the amount ozone generated during use of the device. The calibration value is determined by: measuring ozone concentration in air of a test space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof. In various aspects, one or more unit of measurement describing device operation (e.g., time, power, etc), can be used for determining a calibration value rather than device output. In yet further aspects, a calibration value may be incorporated into the device at the manufacturer-level, based on testing the unit or a similar equivalent unit in a test space. In another aspect, deployment or maintenance of the device can involve running a calibration sequence to obtain a calibration value from the actual space in which the device is being deployed, in which case obtaining the calibration value may be performed via a user, computer, or technician.

[0122] The calibration value can be incorporated into the device as a hardware or software component. For example, the calibration value can be incorporated into the control module as firmware, stored in a computer-readable medium, integrated into the power supply, integrated into the driver, or integrated into the bulb, where suitable based on whether the calibration value resides as a informational software component or a physical component. The calibration value can also be incorporated as an electrical, mechanical, or hardware component. For example, the calibration value can identify an effective radiation output of thedevice based on ozone content, and thus can be an electrical component that a value for effective radiation output upon operation of the device based on power supply information and predetermined room size information based on the size or type of space for which the device is configured. As also illustrated in FIG. 12, the far-UV apparatus 100 contains a far UV radiation source 101 and control module 130. In some alternative aspects, one or more component of the control module 130 can be remote, or the calibration value accessed by the control module 130 can be remote, or both. The control module 130 is configured to process data from one or more sensor, driver 125, power supply 120, memory, computer readable storage, user input, or prior-determined calibration value, using one or more of arithmetic, algorithms, machine learning models, statistical analysis, trend analysis, and other forms of data processing to compare the determined ozone amount to reference values, expected values, or profiles, The control module 130 may access a local or remote database or memory unit containing such reference values or models. The control module 130 includes a processor, a memory, and can be any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine.

[0123] Using the processed data, the control module 130 can regulate the intensity, duration, frequency, or other parameters of the far-UV radiation source 101 to control the level of emitted far-UV irradiation. In various aspects, the control module 130 receives a signal with information useful for determining ozone content in the space in which the device is deployed. The control module 130 can process the received information to determine ozone content, by use of the calibration value, and also determine a proxy measurement of effective radiation output based on the ozone content. The control module 130 may also process the received signal to identify the contribution from the far-UV radiation source 101 with respect to the total measured ozone, which may include background ozone, baseline ozone, or ozone generated by other devices. The amount of ozone generated by the far-UV radiation source 101 provides a proxy measurement which is useful for monitoring or controlling the far-UV radiation source 101. To control the far-UV radiation source 101, the control module 130 sends a signal to a power management module 118 to adjust performance of a driver 125. The driver 125 delivers power from the power supply 120 andmodulates it to manage output from the far-UV radiation source 101. The far-UV apparatus 100 can be mounted on a stand 129 to provide convenient set up and for orienting and elevating the lamp to position to either maximize or minimize areas of direct irradiation, depending on use case. A stand can facilitate portability and placement of the device so that it does not disrupt the intended use of the space being treated. Optionally, the far-UV apparatus can include an air filtration system, which can include one or more mechanical filter and / or one or more scrubber. The scrubber can be an ozone scrubber. The various aspects and discussions provided with respect to the system of FIGS. 1 and 11, apparatus of FIG. 2, and methods illustrated in FIGS. 3, 4, 5, 13, 14, and 15, and the relationships in FIG.10 can also applying, including in their various combinations and permutations, to the method of FIG. 12.

[0124] FIG. 13 illustrates an example method 1300 of regulating UV output of one or more UV radiation source 101 for treatment of a space 110. The method involves a step 1301 of irradiation air of a space with radiation from the UV radiation source 101, which provides far-UV radiation having a spectrum comprising one or more wavelength of about 200 nm to about 400 nm. The method 1300 can involve a step 1302 of determining an amount of ozone in air of the space. The method 1300 can further involve a step 1303 of processing the determined ozone amount to obtain a proxy measurement of effective UV radiation output from the UV radiation source 101. Step 1304 utilizes the proxy measurement to adjust radiation output from the one or more far-UV radiation sources 101. The method illustrated in FIG. 5 can be implemented using an apparatus or system according to FIG. 1, FIG. 2, FIG. 11, and FIG. 12. In various aspects, the method illustrated in FIG. 11 can utilize a specifically configured machine or software process to perform one or more step of the method. The various aspects and discussions provided with respect to the system of FIGS. 1 and 11, apparatus of FIGS.2, and 12, and methods illustrated in FIGS. 3, 4, 5, 14, and 15, and the relationships in FIG. 10 can also applying, including in their various combinations and permutations, to the method of FIG. 13.

[0125] FIG. 14 provides an example method 1400 of regulating UV output of one or more UV radiation source 101 for treatment of a space 110. The method 1400 can involve a sequence 1410 for regulating radiation output from a deviceby use of a calibration value. The method can involve a step 1410 of irradiating air of a space with radiation from the UV radiation source, wherein the radiation comprises one or more wavelengths of about 200 nm to about 400 nm. The method 1400 can involve a step 1412 of indirectly determining an amount of ozone in air of the space via use of previously determined calibration value. The method 1400 can involve a step 1413 of processing the determined ozone amount to obtain a proxy measurement of effective UV irradiation amount. The method 1400 can further involve a step 1414 of adjusting or governing radiation output from the UV radiation source based on the proxy measurement. The method 1400 can also, optionally, involve a sequence 1420 for obtaining a calibration value. The method can thus further involve a step 1421 of previously measuring ozone concentration in air of a space while operating the UV radiation source or equivalent thereof. The method can further involve a step 1422 of processing the measured ozone concentration relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof. The method can involve the step 1421 of subsequently obtaining the calibration value. The various aspects and discussions provided with respect to the system of FIGS. 1 and 11, apparatus of FIGS. 2, and 12, and methods illustrated in FIGS. 3, 4, 5, 13, and 15 and the relationships in FIG. 10 can also applying, including in their various combinations and permutations, to the method of FIG. 14.

[0126] FIG. 15 provides an example method 1500 for inspecting, testing, or calibrating the output of a UV radiation source. The method 1500 can involve a step 1501 of irradiating air of a space with radiation from the UV radiation source, wherein the radiation comprises one or more wavelengths of about 200 nm to about 400 nm. The method 1500 can involve a step 1502 of determining an amount of ozone in air of a space generated from operation of the UV radiation source. The method 1500 can involve a step 1503 of evaluating the determined ozone amount relative to a target value, to obtain a proxy measurement of effective UV radiation output. The method 1500 can involve a step 1504 of passing, failing, scoring, batching, validating, or grading the output of the UV radiation source based on the proxy measurement. The various aspects and discussions provided with respect to the system of FIGS. 1 and 11, apparatus of FIGS. 2, and 12, andmethods illustrated in FIGS. 3, 4, 5, 13, and 14, and the relationships in FIG. 10 can also applying, including in their various combinations and permutations, to the method of FIG. 15.

[0127] Several non-limiting example calculations are provided below to demonstrate how ozone measurements can be used to determine effective UV irradiation (e.g., in terms of radiant flux, irradiance, or radiant exposure) as well as germicidal efficacy and eACH. The present invention is not limited to the Examples given herein. Example 1.Calculating UV irradiance as a function of Ozone generation

[0128] Ozone is created from diatomic oxygen via a two-step process in the presence of high-energy photons:

[0129] The rate at which ozone is produced from diatomic oxygen is a function of the average irradiance in a volume of air, and the size of the volume as it influences the path-length (and so interaction probability) of a UV photon traveling within it. Ozone will disassociate back into diatomic oxygen over time. Additionally, the produced ozone reacts with VOCs and other particles and surfaces in the volume to produce secondary products. The concentration of ozone in a space is also affected by incoming air with a certain ozone concentration and outgoing air with a certain ozone concentration. This can be expressed by a mass balance of the form:

[0130] Where terms express generation and depletion rates of ozone in units of ppb / h or ug / h. For the purposes of providing a simplified explanation of calculations, the mass balance can be simplified by assuming minimal loss and an input flow with no ozone content. A more complex calculation would factor in additional consumption and generation terms for ozone, and adjust for background and / or baseline ozone levels. In various aspects, there can be an input term that is dependent on outside air ozone concentration (e.g., as provided from a natural registry) and flow rate (e.g., as pre-determined or measured from installedventilation), an output term dependent on the current ozone concentration and flow rate, and some number of loss terms dependent on surface deposition and oxidation reactions (e.g., can be determined experimentally, estimated, or bundled with other consumption terms).

[0131] Over time with a fixed production rate of ozone the concentration of ozone in a space will reach a steady-state value.

[0132] Barber et. al. provides a solution to this simplified form of mass balance as:

[0133] where PO3 is an ozone production rate in ppb / hr and k is a decay rate in ACH. For the sake of simplicity in this explanation, decay is assumed to be due solely to exchanged air and that incoming air has zero ozone content. This can also be used to calculate the value at steady state:

[0134] For example, Barber et. al. a O3 production rate of PO3 324 ppb / hr and an air change rate of k ^^^$&+^OHDGV^WR^D^VWHDG\-state ozone content of 324 / 3 §^100 ppb. Note, this Example from Barber represents an extremely high ozone generation rate. A more practical example is provided in Example 3, herein. Indeed, while ozone generation is useful for determining the amount of UV radiation provided to the space, a typical germicidal UV deployment will result in significantly less than 100 ppb at steady state. Given that the production of ozone in air is driven by the presence of UV photons, the relationship of ozone production is linear to average photon flux in a volume, which is linear to average irradiance in that volume (under a fixed spectrum) (See, Poppendieck et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 675^679):

[0135] For example two points are discussed in Barber et. al.: PO3^^^^^SSE^KU at E ^^^^X:^FP2and PO3 ^^^^SSE^KU^DW^E ^^^X:^FP2. This leads us to fit the ozone generation function:

[0136] with the approximate solution k §^ 2000 ppbÂcm2ÂJí1. This fit is dependent on a known volume. More advanced techniques could be used to derive a fit from information about an arbitrary volume. This fit can be used to go from a measured steady state ozone concentration in ppb and a known mechanical air exchange rate to an average irradiance in the volume:

[0137] The mechanical air exchange rate k could be calculated by watching the decay of a tracer gas such as carbon dioxide. Example 2. Germicidal Efficacy, Survival Fraction, and eACH

[0138] The fraction of a pathogen remaining pathogenic (the ^survival fraction^) after a certain dose of UV light can be calculated as:

[0139] Where k is some effectiveness constant in m2 / J. A conservative value for this is k ^ ^^ P2 / J. See, e.g., Buonanno et al. ^Far-89&^ OLJKW^ ^^^^ௗQP^^ efficiently and safely inactivates airborne human coronaviruses^, Scientific Reports volume 10, Article number: 10285 (2020), a copy of which is incorporated by reference herewith. Assuming a constant irradiance E :J / m2, this can be rewritten:

[0140] The metric eACH (effective air changes per hour) can be used to express the survival fraction of pathogenic particles in a space after an hour. This compares to the elimination rate of pathogenic particles by mechanical ventilation (assuming incoming air has zero pathogenic particles for the sake of simplicity in this explanation). The survival fraction for this metric is calculated as:

[0141] These equations can be applied for calculating survival fraction as follows by fixing D ^Et to convert the dose to an irradiance over the period t:

[0142] Simplifying and eliminating the W^terms provides:

[0143] with E in units of W / m2. This is useful to calculate the irradiance suitable to achieve a certain target eACH for a space. Aiming to an eACH of 60, for the purposes of demonstrating this calculation, solving this equation for E provides:

[0144] In the case of a target eACH of 60 hí1the resulting E is §^5.55 mW / m2. Irradiance can then be utilized to calculate the survival fraction of pathogens in the space after an hour by evaluating S_irradiance(1 : hour כ ^^^^^^ ^S_eACH(1 : KRXU^^ ^^.75 כ 10í27. This simplified model yields an approximately 26-log10 reduction in pathogenic content in the space. Another suitable approach to obtain survival fraction is described in Welch et al., a copy of which is incorporated by reference herewith in its entirety, which method utilizes a bi-exponential model for determining viral inactivation and yields a survival fraction of 5.4x10^-17. Both inactivation models easily achieve 99.9% germicidal efficacy. Example 3. Steady-state ozone for 60eACH space

[0145] The steady-state ozone calculation method can be applied to determine the expected ozone concentration in this space with 5.55 mW / m2. Application of equation (9) provides an ozone production rate of PO3(5.55 mW / m2^^ §^4 ppb / hr. Utilizing assumptions for the sake of simplicity in this explanation, when mechanical ventilation rate (with the assumption of no baseline or background contribution to ozone, e.g., due to incoming outside air) is 3 ACH, application of equation (7) provides a steady-state ozone concentration of 4 / 3 §^1.3 ppb ozone.

[0146] The reverse calculation can be based on ozone calculations. For example, supposing a measured steady state ozone concentration of §^1.3 ppb and a known (from e.g., tracer gas decay) mechanical ventilation rate of 3 ACH, application of equation (7) yields an expected 4 ppb / hr generation rate. Use of equation (9) provides an average irradiance for the space of 5.55 mW / m2. This allows measuring the effective irradiation of the space with UV light with easy- to-obtain ozone concentration measurements. An approximately 1.3 ppb steady state concentration of ozone can reflect a germicidal efficacy per hour of greater than 99.9%. Example 4. Volume-Averaged Irradiance Calculation

[0147] The irradiance in a space can be computed by numerically integrating an irradiance-at-distance function for points on the line normal to the emitter plane (i.e., directly in front of the lamp.) This function is based on a function from Poppendieck et. al., but modified to piece wisely model the transition from near- field irradiance to far-field irradiance. This function is as follows:

[0148] This function can be modified by multiplying it by a sigmoid curve which models the radiation pattern of the lamp relative to the 100% irradiance point along in the center of its adiation pattern:

[0149] where A ^^.00479, B ^^.9809, b ^^.7180, c ^^.1196.

[0150] An irradiance function can be derived for a point displaced along the normal axis of the lamp by z cm and offset orthogonally by p cm as follows:

[0151] The z < 5 case is to avoid extreme values during the approach to z ^^^ See, e.g., Poppendieck et al., Environ. Sci. Technol. Lett. 2023, 10, 8, 675^679. This function is then numerically integrated to produce a volumetric irradiance number:

[0152] where h is the height of the cone the irradiance is averaged within, and ɽmaxis the maximum angle considered to be within the radiation pattern of the lamp. The values ɽmax^^^° and z ^^.45m are used in Poppendieck et. al. to arrive at an average irradiance of 0.0327 W / m2.

[0153] This same process can be used in reverse from a known irradiance (such as one derived from a steady-state ozone concentration) to arrive at the irradiance at one meter parameter (known sometimes as E0) which is a good indicator of lamp health for the purpose of maintenance. Using this parameter and a known distribution the total optical power output (in Watts) of the lamp can also be derived. The volume-averaged irradiance value is also useful to calculate the volume of air successfully irradiated in a lamp deployment considering complexities such as reflection, shadowing, occupancy.

[0154] The methods, systems, and apparatus described in the accompanying figures relate generally to the use of far-UV to inactivate pathogens in air, and are particularly useful to monitor, control, or calibrate the amount of far-UV irradiation provided by one or more far-UV radiation source to a space for safely and efficiently inactivating pathogens in air. The methods, systems, and apparatus described herein generally utilize ozone (e.g., as a concentration or generation rate) to obtain a proxy measurement that is used for monitoring or modulating the amount of delivered far-UV irradiation. It can be advantageous to control far-UV radiation sources based on a proxy measurement of a far-UV irradiation derived from ozone measurements. Risks can arise if the amount of far-UV irradiation delivered is too little or too great. If too little radiation is provided, germicidal protection can be insufficient. On the other hand, there are concerns that too much radiation can pose health risks, generate undesirable air contaminants, damage materials, or waste energy. However, it can be difficult to accurately measure and control far-UV irradiation of a space. The methods, systems, and apparatus described herein can have the advantage of permitting accurate measurement and control of far-UV irradiation based on measuring ozone concentration in air rather than directly measuring the radiation itself. As described herein, measuring ozoneconcentration has the advantage of reflecting the effective amount of far-UV radiation acting on the air in the space, which is a more accurate indication for the purpose of assessing the level of germicidal protection afforded to the space. Indeed, ozone levels can be used to target a particular desired ozone efficacy, e.g., 99.9%, 99.99% or 99.999% efficacy, while maintaining balance with other aspects such as threshold limit values (TLV) for radiation or limits on air quality contaminants. Measuring ozone rather than light can also have advantages with respect to reliability, consistency, device calibration, ease of sampling, and location of the detector. Moreover, by utilizing ozone as a proxy measurement of far-UV radiation rather than attempting to measure the radiation itself, a far-UV radiation source or system can better target desired radiation delivery values.

[0155] While the various methods, apparatus, and systems can be advantageously used to ascertain radiation output, and to provide safe, effective germicidal treatment, it is not the only way to provide safe, effective germicidal treatment. Currently, other approaches to ascertaining radiation output can involve direct measuring of the output radiation use of photometers, dosimeters, and the like, which can provide effective measurements of UV radiation output. However, direct measurement of output radiation using such approaches is troublesome because such devices do not disperse throughout the room or reflect how many units of air are being treated, or how the radiation pattern acts upon molecules in air. Ozone molecules move throughout air space which permits an efficient level of information gathering not possible with conventional photometric methods. Moreover, because ozone reaches a steady state in a given space, equilibrium states can be readily identified and offer advantageous states for device performance; using conventional photometric tools do not readily replicate or identify this state. Some existing approaches utilize moving photometers that travel through a room, yet such movement is not as natural and representative as the natural movements of the air that generates ozone. Lastly, numerous approaches have been used to pursue germicidal UV lamps without requiring assessment of current ozone in the space, or configuring irradiation devices or protocols to be attuned to ozone content and responsive to the same. Indeed, prior approaches have largely ignored ozone, sought to eliminate or minimize ozone generation, tested or designed for no excessive ozone generation, or utilized a 5ppb ozone limit, without regard for the manner that ozone levels are dynamic, mediated by the spaces in which the devices are later deployed, and ozone amounts can reflect the presence and extent of germicidal efficacy. Such conventional designs have resulted in devices that at times produce disadvantageously little ozone (and correspondingly disadvantageous germicidal effect) based on a given deployment space, or they produce too much ozone based on the conditions of the deployment space. The presently described approach of utilizing the ozone-derived proxy measurement permits access to devices, configurations, and protocols that achieve higher and more consistent germicidal efficacy.

[0156] The above description is intended to be illustrative, and not restrictive. For example, each of the above-described aspects and features should be understood to optionally be used in any combination with the others. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features can be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter can lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.Exemplified Aspects

[0157] The following aspects are provided as example aspects of the various disclosed subject matter:

[0158] Aspect 1 provides a method for regulating radiation output from a UV radiation source, comprising: irradiating air of a space with radiation from the UV radiation source, wherein the radiation comprises one or more wavelengths of about 200 nm to about 400 nm; determining an amount of ozone in air of the space; processing the determined ozone amount to obtain a proxy measurement of effective UV irradiation; and adjusting or governing radiation output from the UV radiation source based on the proxy measurement.

[0159] Aspect 2 provides a method for regulating, calibrating, testing, or inspecting, a UV radiation source for a space, comprising: obtaining a baseline ozone profile, a target ozone profile, or both, each comprising one or more ozone concentration reference values; determining an amount of ozone in air of the space while operating the UV radiation source to obtain an ozone response; processing the determined ozone amount by evaluating the ozone response against the baseline ozone profile, the target ozone profile, or both, to obtain a proxy measurement of effective UV irradiation; and adjusting or governing radiation output from the UV radiation source or number of UV radiation sources based on the proxy measurement.

[0160] Aspect 3 provides a method according to any one of Aspects 1-2, wherein adjusting radiation output from the UV radiation source comprises increasing radiation output from the UV radiation when the determined ozone amount is less than the minimum target ozone concentration or ozone generation rate.

[0161] Aspect 4 provides a method according to any one of Aspects 1-3, wherein adjusting radiation output from the UV radiation source comprises decreasing radiation output from the UV radiation when the determined ozoneamount is greater than the maximum target ozone concentration or ozone generation rate.

[0162] Aspect 5 provides a method of calibrating, testing, or inspecting a UV radiation output of a UV radiation source, the method comprising: determining an amount of ozone in air of a space generated from operation of the UV radiation source; evaluating the determined ozone amount relative to a target value, to obtain a proxy measurement of effective UV radiation output; passing, failing, scoring, batching, validating, or grading the UV radiation source based on the proxy measurement.

[0163] Aspect 6 provides a method according to Aspect 5, further comprising adjusting the UV radiation source based on the proxy measurement.

[0164] Aspect 7 provides a method according to any one of Aspects 6-7, further comprising comparing the proxy measurement to a target ozone amount, target ozone range, a target radiation output amount, or a target radiation output range.

[0165] Aspect 8 provides a method of measuring UV radiation in a space having one or more UV radiation sources, comprising determining an amount of ozone in air of the space while irradiating the air with the UV radiation source; and processing the determined ozone amount to obtain a proxy measurement for UV irradiation in the space.

[0166] Aspect 9 provides a method of any one of Aspects 1-9, wherein an amount of ozone in air of the space is an ozone concentration or an ozone generation rate.

[0167] Aspect 10 provides a method of any one of Aspects 1-10, wherein an amount of ozone in air of the space is an ozone concentration.

[0168] Aspect 11 provides a method of any one of Aspects 1-11, wherein determining an amount of ozone in air of the space comprises using an ozone detector.

[0169] Aspect 12 provides a method of any one of Aspects 1-12, wherein determining an amount of ozone in air of the space comprises calculating the amount of ozone using a calibration value previously derived by: measuring amount of ozone in air of a test space while operating the UV radiation source orequivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

[0170] Aspect 13 provides a method of any one of Aspects 1-13, wherein determining an amount of ozone in air of the space comprises taking contemporaneous ozone measurements to directly determine the ozone amount.

[0171] Aspect 14 provides a method of any one of Aspects 1-14, wherein determining an amount of ozone in air of the space comprises utilizing contemporaneous non-ozone measurements, non-ozone parameters, or both, and use of a previously-derived calibration value to determine the ozone amount, wherein the calibration value is previously derived by: measuring ozone concentration in air of a space while operating the UV radiation source or equivalent thereof; and processing the measured ozone concentration relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

[0172] Aspect 15 provides a method of any one of Aspects 1-15, wherein processing the determined ozone amount comprises determining an amount of ozone produced due to irradiation from the UV source.

[0173] Aspect 16 provides a method of any one of Aspects 1-16, wherein processing the determined ozone amount comprises evaluating the determined ozone amount relative to one or more non-ozone parameters selected from the group consisting of temperature, humidity, time of day, date, season, location, elevation, ambient pressure, volatile organic compound (VOC) concentration, VOC molecular profile, CO2 concentration, PM2.5 concentration, PM10 concentration, PM0.1 concentration, air quality index (AQI), amount of windows in the space, amount of ventilation in the space, amount of air purification in the space, amount of air exchanges or effective air exchanges provided to the space, volume of space, surface area of space, type of materials in the space, weather, UV index, number of actual or intended occupants of the space, type of actual or intended use of the space, current use status of space, power provided to UV radiation source, on-off status of UV radiation source, emission spectra of UV radiation source, model information and specifications of UV radiation source,details of any additional UV radiation sources in the space, and details of any other ozone-generating devices in the space.

[0174] Aspect 17 provides a method of any one of Aspects 1-17, wherein processing the determined ozone amount comprises evaluating the determined ozone amount relative to one or more ozone reference values.

[0175] Aspect 18 provides a method of any one of Aspects 1-18, wherein processing the determined ozone amount comprises a machine learning process, a predetermined rule-based process, or both.

[0176] Aspect 19 provides a method of Aspect 17, wherein the one or more ozone reference values comprises: a) a baseline, which represents an amount of ozone from ambient sources and non-ambient sources other than the UV radiation source; b) a background, which represents an amount of ozone from ambient sources; c) a cutoff limit, which corresponds to an exposure limit for ozone; d) a lower bound target ozone level; e) an upper bound target ozone level; f) one or more ozone concentrations previously determined for air in the space; g) or any combination thereof.

[0177] Aspect 20 provides a method of Aspect 17 or 19, wherein the one or more ozone reference values are dynamic, variable, adaptive, responsive to changes in parameters of the space, responsive to changes in parameters of the far- UV radiation source, responsive to changes in occupancy, responsive to changes in proximity of the UV radiation source to surfaces or objects, responsive to changes in radar input, responsive to obstruction in irradiation field, responsive to environmental or weather-related changes, responsive to changes in occupantactivities, updated in real-time, responsive to user input, responsive to user activity, responsive to air handling, responsive to changes in ozone scrubber activity, responsive to changes in ventilation, responsive to changes in ozone- generating device activity, responsive to changes in operation of other UV sources in the space; updated daily, updated seasonally, or any combination thereof.

[0178] Aspect 21 provides a method of any one of Aspects 19-20, wherein the baseline, the background, or both accounts for daily, seasonal, or weather-related fluctuations of ozone.

[0179] Aspect 22 provides a method of any one of Aspects 19-21, wherein the background ozone is determined from geolocated ozone data obtained from the Environmental Protection Agency (EPA) Air Quality System (AQS) database, AirNow database, or another such database.

[0180] Aspect 23 provides a method of any one of Aspects 19-22, wherein the lower bound target ozone level is an ozone concentration of 0.01 ppb to 20 ppb.

[0181] Aspect 24 provides a method of any one of Aspects 19-23, wherein the lower bound target ozone level is 0.01 ppb to 10 ppb above the baseline.

[0182] Aspect 25 provides a method of any one of Aspects 19-24, wherein the lower bound target ozone level is 0.01 ppb to 10 ppb above the background.

[0183] Aspect 26 provides a method of any one of Aspects 19-25, wherein when the determined ozone amount is below the lower bound target ozone level, the UV radiation source is adjusted to provide increased radiation to the space.

[0184] Aspect 27 provides a method of any one of Aspects 19-26, wherein when the determined ozone amount is below the lower bound target ozone level, the space is modified to include one or more additional UV radiation sources.

[0185] Aspect 28 provides a method of any one of Aspects 19-27, wherein the upper bound target ozone level is an ozone concentration of 2 ppb to 25 ppb.

[0186] Aspect 29 provides a method of any one of Aspects 19-28, wherein the upper bound target ozone level is 1 ppb to 40 ppb above the baseline.

[0187] Aspect 30 provides a method of any one of Aspects 19-29, wherein the upper bound target ozone level is 1 ppb to 40 ppb above the background.

[0188] Aspect 31 provides a method of any one of Aspects 19-30, wherein when the determined ozone amount is at or above the upper bound target ozone level, the UV radiation source is adjusted to provide reduced radiation to the space.

[0189] Aspect 32 provides a method of any one of Aspects 19-31, wherein when the determined ozone amount is at or above the upper bound target ozone level, the space is modified to remove, attenuate, or stop, one or more UV radiation source from the space.

[0190] Aspect 33 provides a method of any one of Aspects 19-32, wherein the cutoff limit is a maximum ozone concentration safe for an intended human use of the space.

[0191] Aspect 34 provides a method of any one of Aspects 19-33, wherein the cutoff limit is defined by the Occupational Safety and Health Administration (OSHA), National Institute for Occupational Safety & Health (NIOSH), Environmental Protection Agency (EPA), American Conference of Governmental Industrial Hygienists (ACGIH), American National Standards Institute (ANSRI), UL, Illuminating Engineering Society of North America (IES), ASHRAE, or California Air Resources Board (CARB).

[0192] Aspect 35 provides a method of any one of Aspects 19-34, wherein the upper bound target ozone level is substantially less than the cutoff limit.

[0193] Aspect 36 provides a method of any one of Aspects 19-35, wherein when the determined ozone amount is at or above the cutoff limit, the UV radiation source is adjusted to stop or provide reduced radiation to the space.

[0194] Aspect 37 provides a method of any one of Aspects 19-36, wherein the cutoff limit corresponds to one or more of the following: a) 100 ppb over an 8-hour period of intended human use of the space; b) 70 ppb over an 8-hour period of intended human use of the space; c) 80 ppb over an 8-hour period of intended human use of the space; d) 50 ppb over an 8-hour period of intended human use of the space; e) 300 ppb over a 15-minute period of intended human use of the space; or h) about 50 ppb, 100 ppb, 500 ppb, 1,000 ppb, 5,000 ppb or more.

[0195] Aspect 38 provides a method of any one of Aspects 19-37, wherein the determined ozone amount provides an ozone generation rate or an ozone profile for the irradiated space.

[0196] Aspect 39 provides a method of any one of Aspects 19-38, wherein processing the determined ozone amount comprises evaluating ozone concentration against prior measurements of ozone amounts in the space.

[0197] Aspect 40 provides a method of any one of Aspects 19-39, wherein processing the determined ozone amount comprises solving a mass balance equation that represents the space.

[0198] Aspect 41 provides a method of any one of Aspects 19-40, wherein processing the determined ozone amount comprises evaluating ozone concentration against previously determined ozone concentrations.

[0199] Aspect 42 provides a method of any one of Aspects 19-41, wherein processing the determined ozone amount comprises determining a rate of ozone generated due to irradiation from the UV source.

[0200] Aspect 43 provides a method of any one of Aspects 19-42, wherein processing the determined ozone amount comprises evaluating a rate of ozone generation due to irradiation from the UV source relative to a lower bound target ozone generation rate, an upper bound target ozone generation rate, or both.

[0201] Aspect 44 provides a method of Aspect 43, wherein the lower bound target ozone generation rate is 0.05 ppb / h to 500 ppb / h per UV radiation source.

[0202] Aspect 45 provides a method of any one of Aspects 40-44, wherein the ORZHU^ERXQG^WDUJHW^R]RQH^JHQHUDWLRQ^UDWH^LV^^^^^XJ^^KÂZ^^WR^^^^XJ^^KÂZ^^^EDVHG^RQ^ electrical power (w) of the UV radiation source.

[0203] Aspect 46 provides a method of any one of Aspects 40-45, wherein when the rate of ozone generation due to irradiation from the UV source is below the lower bound target ozone generation rate, the UV radiation source is adjusted to provide increased radiation to the space.

[0204] Aspect 47 provides a method of any one of Aspects 40-46, wherein when the rate of ozone generation due to irradiation from the UV source is below the lower bound target ozone generation rate, the space is modified to include one or more additional UV radiation sources.

[0205] Aspect 48 provides a method of any one of Aspects 40-47, wherein the upper bound target ozone generation rate is 10 ppb / h to 5000 ppb / h per UV radiation source.

[0206] Aspect 49 provides a method of any one of Aspects 40-48, wherein the upper bound target ozone generation rate is 5 XJ^^KÂZ^^WR^^^^XJ^^KÂZ^^^EDVHG^RQ^ electrical power (w) of the UV radiation source.

[0207] Aspect 50 provides a method of any one of Aspects 40-49, wherein when the rate of ozone generation due to irradiation from the UV source is above the upper bound target ozone generation rate, the UV radiation source is adjusted to provide increased radiation to the space.

[0208] Aspect 51 provides a method of any one of Aspects 40-50, wherein when the rate of ozone generation due to irradiation from the UV source is above the upper bound target ozone generation rate, the space is modified to include one or more additional UV radiation sources.

[0209] Aspect 52 provides a method of any one of Aspects 1-51, wherein determining the ozone amount in air of the space is performed by an ozone detector.

[0210] Aspect 53 provides a method of any one of Aspects 1-52, wherein determining the ozone amount in air of the space is performed by an ozone detector located outside an area of direct irradiation from the UV radiation source.

[0211] Aspect 54 provides a method of any one of Aspects 1-53, wherein the UV radiation source is coupled with an ozone detector in a single apparatus.

[0212] Aspect 55 provides a method of any one of Aspects 1-54, wherein determining the ozone amount in air of the space is performed over multiple samples.

[0213] Aspect 56 provides a method of any one of Aspects 1-55, wherein determining the ozone amount in air of the space is performed by periodic sampling or constant sampling.

[0214] Aspect 57 provides a method of any one of Aspects 1-56, wherein determining the ozone amount in air of the space is performed by calculating the ozone amount using a calibration value previously derived by: measuring ozone amount in air of a space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated,measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

[0215] Aspect 58 provides a method of any one of Aspects 1-57, wherein determining the ozone amount in air of the space is performed by calculating the ozone amount using a calibration value that corresponds to the amount of ozone generated by operation of the UV radiation source.

[0216] Aspect 59 provides a method of any one of Aspects 1-58, wherein determining the ozone amount in air of the space is performed by calculating the ozone amount using a calibration value that corresponds to the amount of ozone generated per unit power, per unit time, or both, together with a known amount of power supplied to the UV radiation source, a known amount of time which the UV radiation source is operated, or both.

[0217] Aspect 60 provides a method of any one of Aspects 1-59, wherein the radiation comprises 222 nm light.

[0218] Aspect 61 provides a method of any one of Aspects 1-60, wherein the radiation comprises one or more wavelengths of about 210 nm to about 230 nm.

[0219] Aspect 62 provides a method of any one of Aspects 1-61, wherein the radiation comprises one or more wavelengths of about 240 nm to about 280 nm.

[0220] Aspect 63 provides a method of any one of Aspects 1-62, wherein the radiation comprises 222 nm light.

[0221] Aspect 64 provides a method of any one of Aspects 1-63, wherein the radiation comprises one or more wavelengths of about 210 nm to about 230 nm.

[0222] Aspect 65 provides a method of any one of Aspects 1-64, wherein the radiation comprises one or more wavelengths of about 240 nm to about 280 nm.

[0223] Aspect 66 provides a method of any one of Aspects 1-65, wherein the UV radiation source comprises an optical filter.

[0224] Aspect 67 provides a method of any one of Aspects 1-66, wherein the UV radiation source comprises an optical filter that substantially prevents transmittance of one or more wavelength outside of the range between about 210 nm to about 230 nm.

[0225] Aspect 68 provides a method of any one of Aspects 1-67, wherein the UV radiation source comprises an optical filter that substantially transmits one or more wavelength between about 240 nm to about 280 nm.

[0226] Aspect 69 provides a method of any one of Aspects 1-68, wherein the UV radiation source is powered by a driver that is controlled by a control module based on the determined ozone amount.

[0227] Aspect 70 provides a method of any one of Aspects 1-69, wherein adjusting radiation output from the UV radiation source comprises increasing, decreasing, or maintaining radiation output based on the determined ozone amount.

[0228] Aspect 71 provides a method of any one of Aspects 1-70, wherein adjusting radiation output from the UV radiation source comprises modulating a power supply or driver that powers the UV radiation source, and wherein governing radiation output from the UV radiation source comprises limiting, or enforcing an upper limit or lower limit of a parameter, of the power supply or driver that powers the UV radiation source.

[0229] Aspect 72 provides a method of any one of Aspects 1-71, which is applied to multiple UV radiation sources.

[0230] Aspect 73 provides a method of any one of Aspects 1-72, which dynamically adjusts effective UV radiation output based on one or more determination of amount of ozone of the space so as to achieve a variable UV radiation output, occupant radiation exposure, surface radiation amount, germicidal efficacy, occupant infection risk, or any combination thereof, within a target ozone amount range.

[0231] Aspect 74 provides a method of any one of Aspects 1-73, which dynamically adjusts operation of the UV radiation source based on one or more determination of ozone amount of the space so as to maintain a minimum, average, target, or maximum, UV radiation output, occupant radiation exposure, surface radiation amount, germicidal efficacy, occupant infection risk, or any combination thereof.

[0232] Aspect 75 provides a method of any one of Aspects 1-74, wherein determining the amount of ozone is repeatedly continuously or repeatedly.

[0233] Aspect 76 provides a method of any one of Aspects 1-75, which dynamically adjusts operation of the UV radiation source based on the determined ozone amount.

[0234] Aspect 77 provides a method of any one of Aspects 1-76, wherein UV radiation output is dynamically adjusted or managed based on changes in the proxy measurement, non-ozone parameters, target ozone values, or any combination thereof.

[0235] Aspect 78 provides a method of any one of Aspects 1-77, which repeatedly determines ozone amounts and dynamically adjusts operation of the UV radiation source to increase ozone when ozone is below a lower bound target ozone amount; to decrease ozone when ozone is above an upper bound target ozone amount; to increase ozone to avoid an ozone amount below a lower bound target ozone amount; to decrease ozone to avoid an ozone amount above an upper bound target ozone amount; or any combination thereof.

[0236] Aspect 79 provides a method of any one of Aspects 1-78, which determines ozone amount in real time, dynamically adjusts operation of the UV radiation source in real time, or both.

[0237] Aspect 80 provides a method of any one of Aspects 1-79, which dynamically adjusts a target ozone amount, a target ozone amount range, a cutoff limit, a lower bound target ozone level, an upper bound target ozone level, or any combination thereof, based on one or more detected parameter of the space, UV radiation source, other devices deployed to purify air in the space, or any combination thereof.

[0238] Aspect 81 provides a method of any one of Aspects 1-80, which is used to design, configure, calibrate, test, or validate a germicidal UV apparatus.

[0239] Aspect 82 provides a method of inactivating a pathogen in air with germicidal UV, comprising the method of any one of Aspects 1-81.

[0240] Aspect 83 provides a system for regulating radiation output from a UV radiation source, comprising: a UV radiation source configured for irradiating air of a space, wherein the UV radiation source emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm; a component for determining an ozone amount in air of the space based on operation of the UV radiation source; and a control module configured for processing the determined ozone amount to obtain a proxy measurement of effective UV irradiation, and configured toadjust or govern radiation output of the one or more UV radiation source based on the proxy measurement.

[0241] Aspect 84 provides a system of Aspect 83, wherein the control module directs the UV radiation source to adjust radiation output based on the proxy measurement.

[0242] Aspect 85 provides a system of any one of Aspects 83-84, wherein the component for determining an amount of ozone in air of the space comprises an ozone detector.

[0243] Aspect 86 provides a system of any one of Aspects 83-85, wherein the component for determining an amount of ozone in air of the space comprises a firmware, a software, a memory, or a computer-readable medium for calculating ozone amount in air of the treatment based on a calibration value and one or more non-ozone sensor, non-ozone parameter of the space, or non-ozone operating parameter of the system or a component thereof, wherein the calibration value is derived by: measuring ozone amount in air of a space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

[0244] Aspect 87 provides a system of any one of Aspects 83-86, wherein the component for determining an ozone amount in air of the space comprises an electrical, mechanical, or hardware component configured to determine ozone amount in air of the treatment based on a calibration value and one or more non- ozone sensor, non-ozone parameter of the space, or non-ozone operating parameter of the system or a component thereof, wherein the calibration value is derived by: measuring ozone amount in air of a test space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

[0245] Aspect 88 provides a system of any one of Aspects 83-87, wherein the UV radiation source provides radiation comprising 222 nm light.

[0246] Aspect 89 provides a system of any one of Aspects 83-88, wherein the UV radiation source provides radiation comprising one or more wavelengths of about 210 nm to about 230 nm.

[0247] Aspect 90 provides a system of any one of Aspects 83-89, wherein the UV radiation source provides radiation comprising one or more wavelengths of about 240 nm to about 280 nm.

[0248] Aspect 91 provides a system of any one of Aspects 83-90, wherein the UV radiation source comprises an optical filter.

[0249] Aspect 92 provides a system of any one of Aspects 83-91, wherein the UV radiation source is a krypton chloride excimer lamp.

[0250] Aspect 93 provides a system of any one of Aspects 83-92, wherein the UV radiation source is powered by a driver that is controlled by a control module based on the determined ozone amount.

[0251] Aspect 94 provides a system of any one of Aspects 83-93, wherein the control module increases, decreases, or maintains radiation output based on the determined ozone amount.

[0252] Aspect 95 provides a system of any one of Aspects 83-94, wherein the control module adjusts radiation output from the UV radiation source via modulating a power supply or driver that powers the UV radiation source.

[0253] Aspect 96 provides a system of any one of Aspects 83-95, which comprises multiple UV radiation sources.

[0254] Aspect 97 provides a system of any one of Aspects 83-96, wherein the one or more target reference values are dynamic, variable, responsive to changes in parameters of the space, responsive to changes in parameters of the far-UV radiation source, responsive to changes in occupancy, responsive to environmental or weather-related changes, responsive to changes in occupant activities, updated in real-time, responsive to user input, responsive to user activity, responsive to air handling, responsive to changes in ozone scrubber activity, responsive to changes in ventilation, responsive to changes in ozone- generating device activity, responsive to changes in operation of other UV sources in the space; updated daily, updated seasonally, or any combination thereof.

[0255] Aspect 98 provides a system of any one of Aspects 83-97, wherein the control module determines one or more target reference value based on one or more non-ozone sensor, non-ozone parameter of the space, non-ozone operating parameter of the system or a component thereof, or any combination thereof.

[0256] Aspect 99 provides a system of any one of Aspects 83-98, wherein the control module dynamically adjusts effective UV radiation output based on one or more determination of ozone amount of the space so as to achieve a variable UV radiation output, occupant radiation exposure, surface radiation amount, germicidal efficacy, occupant infection risk, or any combination thereof, within a target ozone amount range.

[0257] Aspect 100 provides a system of any one of Aspects 83-99, wherein the control module dynamically adjusts operation of the UV radiation source based on one or more determination of ozone amount of the space so as to maintain a minimum, average, target, or maximum, UV radiation output, occupant radiation exposure, surface radiation amount, germicidal efficacy, occupant infection risk, or any combination thereof.

[0258] Aspect 101 provides a system of any one of Aspects 83-100, wherein the control module repeatedly determines ozone amount of the space and dynamically adjusts operation of the UV radiation source based on the determined ozone amount.

[0259] Aspect 102 provides a system of any one of Aspects 83-101, wherein the control module repeatedly determines ozone amount and dynamically adjusts operation of the UV radiation source based on the determined ozone amount to maintain a target ozone amount.

[0260] Aspect 103 provides a system of any one of Aspects 83-102, wherein the control module repeatedly determines ozone amount and dynamically adjusts operation of the UV radiation source based on the determined ozone amount to maintain a target ozone amount, or to maintain an ozone amount within a target range.

[0261] Aspect 104 provides a system of any one of Aspects 83-103, wherein the control module repeatedly determines ozone amount and dynamically adjusts operation of the UV radiation source to increase ozone amount when ozone amount is below a lower bound target ozone amount; to decrease ozone amount when ozone amount is above an upper bound target ozone amount; or both.

[0262] Aspect 105 provides a system of any one of Aspects 83-104, wherein the control module determines ozone amounts in real time, dynamically adjusts operation of the UV radiation source in real time, or both.

[0263] Aspect 106 provides a system of any one of Aspects 83-105, wherein the control module dynamically adjusts a target ozone amount, a target ozone amount range, a cutoff limit, a lower bound target ozone level, an upper bound target ozone level, or any combination thereof, based on one or more detected parameter of the space, UV radiation source, other devices deployed to purify air in the space, or any combination thereof.

[0264] Aspect 107 provides a system of any one of Aspects 83-106, wherein the control module dynamically adjusts effective UV radiation output based on one or more determination of ozone amount of the space so as to achieve a variable UV radiation output, occupant radiation exposure, surface radiation amount, germicidal efficacy, occupant infection risk, or any combination thereof, within a target ozone amount range.

[0265] Aspect 108 provides a system of any one of Aspects 83-107, wherein the control module dynamically adjusts operation of the UV radiation source based on one or more determination of ozone amount of the space so as to maintain a minimum, average, target, or maximum, UV radiation output, occupant radiation exposure, surface radiation amount, germicidal efficacy, occupant infection risk, or any combination thereof.

[0266] Aspect 109 provides a system of any one of Aspects 83-108, which repeatedly determines ozone amounts of the space and dynamically adjusts operation of the UV radiation source based on the determined ozone amounts.

[0267] Aspect 110 provides a system of any one of Aspects 83-109, which determines ozone amounts in real time, dynamically adjusts operation of the UV radiation source in real time, or both.

[0268] Aspect 111 provides a system of any one of Aspects 83-110, which is used to design, configure, calibrate, test, or validate a germicidal UV apparatus.

[0269] Aspect 112 provides a system, comprising: a UV radiation source configured for irradiating air of a space, wherein the UV radiation source emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm; a component for determining an amount of ozone in air of the space generated by operation of the UV radiation source; anda control module configured for evaluating the determined ozone amount against one or more ozone reference values, processing the determined ozone amount to provide a proxy measurement for UV irradiation, and assessing UV irradiation based on the proxy measurement, wherein the system is configured to perform the method of any one of Aspects 1-82.

[0270] Aspect 113 provides an apparatus for inactivating a pathogen in air of a space, comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, a component for determining an amount of ozone in air of the space, and a control module configured to process the determined ozone amount to obtain a proxy measurement of effective UV irradiation and configured to adjust or govern radiation output of the UV radiation source based on the proxy measurement.

[0271] Aspect 114 provides an apparatus for inactivating a pathogen in air of a space, comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, a component for determining an amount of ozone in air of the space, and a control module that regulates the UV radiation source to provide an ozone concentration in air of the space of at least 0.01 ppb above baseline, less than 50 ppb overall, or both.

[0272] Aspect 115 provides an apparatus for inactivating a pathogen in air of a space, comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, and a control module that regulates the UV radiation source to provide an ozone concentration in air of the space of at least 0.01 ppb above baseline, less than 50 ppb overall, or both.

[0273] Aspect 116 provides an apparatus for inactivating a pathogen in air of a space, comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, and a control module that regulates the UV radiation source to provide a resulting ozone amount determined based on a calibration value stored in the control module, wherein the calibration value is previously determined by: measuring ozone amount in air of a space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

[0274] Aspect 117 provides an apparatus of any one of Aspects 113-116, wherein the control module directs the UV radiation source to adjust radiation output based on the proxy measurement.

[0275] Aspect 118 provides an apparatus of any one of Aspects 113-117, wherein the component for determining an amount of ozone in air of the space comprises an ozone detector.

[0276] Aspect 119 provides an apparatus of any one of Aspects 113-118, wherein the component for determining an amount of ozone in air of the space comprises a firmware containing a calibration value for calculating ozone amount in air of the treatment based on one or more non-ozone sensor, non-ozone parameter of the space, or non-ozone operating parameter of the apparatus or a component thereof, wherein the calibration value is derived by: measuring ozone amount in air of a space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

[0277] Aspect 120 provides an apparatus of any one of Aspects 113-119, wherein the a component for determining an amount of ozone in air of the space comprises an electrical or hardware component configured to determine ozone amount in air of the treatment based on a calibration value and one or more non- ozone sensor, non-ozone parameter of the space, or non-ozone operating parameter of the apparatus or a component thereof, wherein the calibration value is derived by: measuring ozone amount in air of a space while operating the UV radiation source or equivalent thereof; and processing the measured ozone amount relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

[0278] Aspect 121 provides an apparatus of any one of Aspects 113-120, wherein the UV radiation source provides radiation comprising 222 nm light.

[0279] Aspect 122 provides an apparatus of any one of Aspects 113-121, wherein the UV radiation source provides radiation comprising one or more wavelengths of about 210 nm to about 230 nm.

[0280] Aspect 123 provides an apparatus of any one of Aspects 113-122, wherein the UV radiation source provides radiation comprising one or more wavelengths of about 240 nm to about 280 nm.

[0281] Aspect 124 provides an apparatus of any one of Aspects 113-123, wherein the UV radiation source comprises an optical filter.

[0282] Aspect 125 provides an apparatus of any one of Aspects 113-124, wherein the UV radiation source is a krypton chloride excimer lamp.

[0283] Aspect 126 provides an apparatus of any one of Aspects 113-125, wherein the UV radiation source is powered by a driver that is controlled by a control module based on the determined ozone concentration.

[0284] Aspect 127 provides an apparatus of any one of Aspects 113-126, wherein the control module increases, decreases, or maintains radiation output based on the determined ozone amount.

[0285] Aspect 128 provides an apparatus of any one of Aspects 113-127, wherein the control module adjusts radiation output from the UV radiation source via modulating a power supply or driver that powers the UV radiation source.

[0286] Aspect 129 provides an apparatus of any one of Aspects 113-128, which comprises multiple UV radiation sources.

[0287] Aspect 130 provides an apparatus of any one of Aspects 113-129, wherein the one or more target reference values are dynamic, variable, responsive to changes in parameters of the space, responsive to changes in parameters of the far-UV radiation source, responsive to changes in occupancy, responsive to environmental or weather-related changes, responsive to changes in occupant activities, updated in real-time, responsive to user input, responsive to user activity, responsive to air handling, responsive to changes in ozone scrubber activity, responsive to changes in ventilation, responsive to changes in ozone- generating device activity, responsive to changes in operation of other UV sources in the space; updated daily, updated seasonally, or any combination thereof.

[0288] Aspect 131 provides an apparatus of any one of Aspects 113-130, wherein the control module determines one or more target reference value based on one or more non-ozone sensor, non-ozone parameter of the space, non-ozone operating parameter of the apparatus or a component thereof, or any combination thereof.

[0289] Aspect 132 provides an apparatus of any one of Aspects 113-131, wherein the control module dynamically adjusts effective UV radiation output based on one or more determination of ozone amount of the space so as to achieve a variable UV radiation output, occupant radiation exposure, surface radiation amount, germicidal efficacy, occupant infection risk, or any combination thereof, within a target ozone amount range.

[0290] Aspect 133 provides an apparatus of any one of Aspects 113-132, wherein the control module dynamically adjusts operation of the UV radiation source based on one or more determination of ozone amount of the space so as to maintain a minimum, average, target, or maximum, UV radiation output, occupant radiation exposure, surface radiation amount, germicidal efficacy, occupant infection risk, or any combination thereof.

[0291] Aspect 134 provides an apparatus of any one of Aspects 113-133, which repeatedly determines ozone amount of the space and dynamically adjusts operation of the UV radiation source based on the determined ozone amounts.

[0292] Aspect 135 provides an apparatus of any one of Aspects 113-134, which determines ozone amount in real time, dynamically adjusts operation of the UV radiation source in real time, or both.

[0293] Aspect 136 provides an apparatus of any one of Aspects 113-135, which is used to design, configure, calibrate, test, or validate a germicidal UV apparatus.

[0294] Aspect 137 provides an apparatus of any one of Aspects 113-136, wherein the control module is configured to regulate the UV radiation source to provide a lower bound target ozone level of an ozone concentration of 0.01 ppb to 20 ppb in air of the space.

[0295] Aspect 138 provides an apparatus of any one of Aspects 113-137, wherein the control module is configured to regulate the UV radiation source to provide a lower bound target ozone level of 0.01 ppb to 20 ppb in air of the space.

[0296] Aspect 139 provides an apparatus of any one of Aspects 113-138, wherein the control module is configured to regulate the UV radiation source to provide a lower bound target ozone level of 0.01 ppb to 10 ppb above baseline in air of the space.

[0297] Aspect 140 provides an apparatus of any one of Aspects 113-139, wherein the control module is configured to regulate the UV radiation source to provide a lower bound target ozone level of 0.01 ppb to 10 ppb above background in air of the space.

[0298] Aspect 141 provides an apparatus of any one of Aspects 113-140, wherein the control module is configured to increase radiation to the space when the determined ozone amount is below a lower bound target ozone level in air of the space.

[0299] Aspect 142 provides an apparatus of any one of Aspects 113-141, wherein the control module is configured to regulate the UV radiation source to provide an upper bound target ozone level of 2 ppb to 25 ppb in air of the space.

[0300] Aspect 143 provides an apparatus of any one of Aspects 113-142, wherein the control module is configured to regulate the UV radiation source to provide an upper bound target ozone level of 1 ppb to 40 ppb above the baseline in air of the space.

[0301] Aspect 144 provides an apparatus of any one of Aspects 113-143, wherein the control module is configured to regulate the UV radiation source to provide an upper bound target ozone level of 1 ppb to 40 ppb above background in air of the space.

[0302] Aspect 145 provides an apparatus of any one of Aspects 113-144, wherein the control module is configured to reduce radiation to the space when the determined ozone amount is at or above an upper bound target ozone level in air of the space.

[0303] Aspect 146 provides an apparatus of any one of Aspects 113-145, wherein the control module is configured to reduce radiation to the space when the determined ozone amount is at or above an upper bound target ozone level in air of the space, and wherein the upper bound target ozone level is substantially less than a maximum ozone concentration safe for an intended human use of the space.

[0304] Aspect 147 provides an apparatus of any one of Aspects 113-146, wherein the control module is configured to evaluate the determined ozone amount against prior measurements of ozone amounts in the space.

[0305] Aspect 148 provides an apparatus of any one of Aspects 113-147, wherein the control module is configured to processing the determined ozone amount by solving a mass balance equation that represents the space.

[0306] Aspect 149 provides an apparatus of any one of Aspects 113-148, wherein the control module is configured to determine a rate of ozone generated due to irradiation from the UV source.

[0307] Aspect 150 provides an apparatus of any one of Aspects 113-149, wherein the control module is configured to determine a rate of ozone generated due to irradiation from the UV source and evaluate against a lower bound target ozone generation rate, an upper bound target ozone generation rate, or both.

[0308] Aspect 151 provides an apparatus of any one of Aspects 113-150, wherein the control module is configured to regulate the UV radiation source to provide a lower bound target ozone generation rate of 0.05 ppb / h to 500 ppb / h per UV radiation source.

[0309] Aspect 152 provides an apparatus of any one of Aspects 113-151, wherein the control module is configured to regulate the UV radiation source to provide a lower bound target ozone generation rate of ^^^^XJ^^KÂZ^^WR^^^^XJ^^KÂZ^^^ based on electrical power (w) of the UV radiation source.

[0310] Aspect 153 provides an apparatus of any one of Aspects 113-152, wherein the control module is configured to increase radiation to the space when a determined rate of ozone generation due to irradiation from the UV source is below a lower bound target ozone generation rate.

[0311] Aspect 154 provides an apparatus of any one of Aspects 113-153, wherein the control module is configured to decrease radiation to the space when a determined rate of ozone generation due to irradiation from the UV source is above an upper bound target ozone generation rate.

[0312] Aspect 155 provides an apparatus of any one of Aspects 113-154, wherein the control module is configured to regulate the UV radiation source to provide an upper bound target ozone generation rate of 10 ppb / h to 5000 ppb / h per UV radiation source in air of the space.

[0313] Aspect 156 provides an apparatus of any one of Aspects 113-155, wherein the control module is configured to regulate the UV radiation source toprovide an upper bound target ozone generation rate of ^^XJ^^KÂZ^^WR^^^^XJ^^KÂZ^^^ based on electrical power (w) of the UV radiation source, in air of the space.

[0314] Aspect 157 provides an apparatus for inactivating a pathogen in air of a space, comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, a component configured to determine an amount of ozone in the space, and a control module that regulates the UV radiation source based on the determined ozone amount, wherein the apparatus is configured to perform the method of any one of Aspects 1-82.

[0315] Aspect 158 provides an apparatus, method, or system incorporating any combination or permutation of one or more of the aforementioned features in Aspects 1-141.

[0316] Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.

Claims

CLAIMS What is claimed is:

1. A method, comprising: irradiating air of a space with radiation from the UV radiation source, wherein the radiation comprises one or more wavelengths of about 200 nm to about 400 nm; determining an amount of ozone in air of the space; processing the determined ozone amount to obtain a proxy measurement of effective UV irradiation; and adjusting or governing radiation output from the UV radiation source based on the proxy measurement.

2. The method of claim 1, wherein adjusting radiation output from the UV radiation source comprises increasing radiation output from the UV radiation when the determined ozone amount is less than the minimum target ozone concentration or a minimum target ozone rate.

3. The method of claim 1, wherein adjusting radiation output from the UV radiation source comprises decreasing radiation output from the UV radiation when the determined ozone amount is greater than the maximum target ozone concentration or a maximum target ozone rate.

4. The method of claim 1, wherein the amount of ozone in air of the space is an ozone concentration of the space overall or of the amount contributed by the UV radiation source.

5. The method of claim 1, wherein the amount of ozone in air of the space is an ozone generation rate of the UV radiation source.

6. The method of claim 1, wherein determining an amount of ozone in air of the space comprises using an ozone detector.

7. The method of claim 1, wherein determining an amount of ozone in air of the space comprises calculating the ozone amount using a calibration value previously derived by: measuring amount of ozone in air of a test space while operating the UV radiation source or equivalent thereof; and processing themeasured ozone concentration relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

8. The method of claim 1, wherein determining an amount of ozone in air of the space comprises obtaining one or more non-ozone parameter to determine ozone amount by utilizing a calibration value, which is previously derived by: measuring an ozone amount in air of a space while operating the UV radiation source or equivalent thereof to irradiate the space; and processing the measured ozone concentration relative to a calculated, measured, estimated, or known amount of UV radiation generated by operation of the UV radiation source or equivalent thereof.

9. The method of claim 1, wherein processing the determined ozone amount comprises evaluating the determined ozone amount relative to one or more ozone reference values.

10. The method of claim 9, wherein the one or more ozone reference values comprises: a) a baseline, which represents an amount of ozone from ambient sources and non-ambient sources other than the UV radiation source; b) a background, which represents an amount of ozone from ambient sources; c) a cutoff limit, which corresponds to an exposure limit for ozone; d) a lower bound target ozone level; e) an upper bound target ozone level; f) one or more ozone concentrations previously determined for air in the space; g) or any combination thereof.

11. The method of claim 10, wherein the one or more ozone reference values are dynamic and responsive to changes in parameters of the space, responsive to changes in parameters of the far-UV radiation source, responsive to changes in occupancy, responsive to changes in proximity of the UV radiation source to surfaces or objects, responsive to changes in radar input, responsive to obstruction in irradiation field, responsive to changes responsive to environmental or weather-related changes, responsive to changes in occupant activities, updated in real-time, responsive to user input, responsive to user activity, responsive to air handling, responsive to changes in ozone scrubber activity, responsive to changes in ventilation, responsive to changes in ozone- generating device activity, responsive to changes in operation of other UV sources in the space; updated daily, updated seasonally, or any combination thereof.

12. The method of claim 1, wherein the UV radiation source is powered by a driver that is controlled by a control module based on the proxy measurement.

13. The method of claim 1, wherein determining the amount of ozone is performed repeatedly or continuously.

14. The method of claim 1, wherein UV radiation output is dynamically adjusted or managed based on changes in the proxy measurement, non-ozone parameters, target ozone values, or any combination thereof.

15. The method of claim 8, wherein the one or more non-ozone parameter comprises information about the space, and wherein the method further comprising utilizing a camera to obtain information about the space.

16. The method of claim 8, wherein the one or more non-ozone parameter comprises information about the space, and wherein the method further comprising utilizing a camera to obtain information about the space.

17. The method of claim 8, wherein the one or more non-ozone parameter comprises information about the space, and wherein the method further comprising utilizing a camera to obtain information about the space.

18. A system, comprising: a UV radiation source configured for irradiating air of a space, wherein the UV radiation source emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm; a component for determining an amount of ozone in air of the space generated by operation of the one or more UV radiation source; and a control module configured for processing the determined ozone amount to obtain a proxy measurement of effective UV irradiation, and configured to adjust or govern radiation output of the one or more UV radiation source based on the proxy measurement.

19. An apparatus for inactivating a pathogen in air of a space, comprising a UV radiation source that emits radiation comprising one or more wavelengths of about 200 nm to about 400 nm, a component for determining an amount of ozone in air of the space, and a control module configured to process the determined ozone amount to obtain a proxy measurement of effective UV irradiation and configured to adjust or govern radiation output of the UV radiation source based on the proxy measurement.

20. The apparatus of claim 19, wherein the control module regulates the UV radiation source to provide an ozone concentration in air of the space of at least 0.01 ppb above baseline, less than 50 ppb overall, or both.

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