Portable and filter-free one-way air sterilization system

Abstract

Two portable disinfection systems for indoor air disinfection are provided. One system is designed to be equipped with an external far UVC lamp as a UV source, while another system is designed to be equipped with an internal far UVC tubular lamp as a UV source. The portability of the system enables the system to be universal and suitable for different scenes. For example, the portability of these systems is versatile and applicable to room disinfection and public traffic scenarios. The system may act as a stand-alone air disinfection unit or be integrated with the prior art to further reduce airborne pathogen concentration.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 590,000 filed on October 13, 2023 and U.S. Patent Application No. 18 / 806,743 filed on August 16, 2024, which are incorporated herein by reference in their entirety. Technical Field

[0002] The present invention generally relates to devices related to ultraviolet (UV) radiation, including sterilization technology, air purification systems and UV radiation applications. Background Art

[0003] In response to the challenges posed by airborne transmission of pathogens such as SARS-CoV-2, a variety of technologies have been explored to improve the safety of indoor air. Traditional approaches in commercial buildings, such as mechanical ventilation and filtration systems, have limitations such as high cost and difficult maintenance. Mechanical ventilation, while effective, may be impractical to implement in existing structures, and filters, while capable of capturing bioaerosols, require frequent replacement and can serve as breeding grounds for pathogens if not properly maintained.

[0004] Ultraviolet germicidal irradiation (UVGI) has emerged as a promising alternative. UVGI directly inactivates microorganisms, thereby significantly reducing indoor microbial concentrations. When integrated with high-efficiency particulate air (HEPA) filters, UVGI systems have been shown to significantly reduce the infectivity of airborne bacteria and viruses in commercial environments. Studies have shown that when UVGI is combined with HEPA filters, airborne bacteria are reduced by up to 73%. 3 In another study, products equipped with 254 nm UVC and HEPA filters were reported to reduce viral infectivity of Phi6-phages in indoor 4 Even in the absence of HEPA filters, these systems were still able to reduce the infectivity of viruses by more than 70%.

[0005] Types of UVGI systems include: (1) Upper Room UVGI: Positioned high up in a room, this system disinfects the air directly in the upper area; however, its efficacy may be affected by local airflow patterns; (2) In-Duct UVGI: Integrated into the central HVAC system, in-duct UVGI disinfects the air as it circulates through the building's ventilation network; (3) Portable UVGI Systems: These systems have gained popularity during epidemics for their effectiveness in reducing airborne and ground-borne pathogens. Combining medium-efficiency filters with UVGI, portable systems have significantly reduced pathogens and do not require filter changes.

[0006] It was reported that UVGI equipped with 254 nm UVC reduced the virulence of Phi6-phage indoors to 28.7%, and when a HEPA filter was added, the value was further reduced to 0.6% 5 Therefore, UVGI has the potential to replace filters to purify indoor air when particulate matter (PM) is not a major concern. However, the routine use of low-pressure mercury lamps emitting 254 nm UV may raise environmental and health issues due to the risk of mercury leakage and potential harm to the skin and eyes. On the other hand, high flow rates may pose challenges to the disinfection performance of the system.

[0007] Prototype studies at a flow rate of 1254 L / min demonstrated that the device can be effectively disinfected by applying UV reflective materials and adopting appropriate structural design 6 However, the study mentioned that when multiple UV sources are installed, the air channel surface temperature is higher, which raises concerns about the heat dissipation of the UV sources.

[0008] Given the limitations of low-pressure mercury lamps, other wavelengths of UV radiation sources and materials have been explored and tested. For example, deep ultraviolet 405 nm blue light emitted by LEDs (light emitting diodes). The antimicrobial effect of UVC-LEDs has been demonstrated in several studies. 7-9 However, challenges remain with the low output of individual LEDs and the significant heat dissipation that occurs during LED illumination. While the use of 405 nm blue light is feasible, it exhibits relatively low efficacy in microbial inactivation, typically requiring higher doses to achieve effective results.

[0009] The field of air disinfection technology faces many challenges that require continued in-depth research and innovation to increase efficiency, reduce costs, and improve safety and health to better meet the diverse needs of different environments. Summary of the invention

[0010] The present invention is designed to evaluate a portable system that utilizes multiple UV light sources with unique characteristics to achieve efficient disinfection at practical high airflow rates. The system is able to effectively inactivate microorganisms using far-UVC light at high airflow rates. Unlike existing filter-based air purifiers, the system designed by the present invention eliminates indoor airborne microorganisms by inactivating airborne microorganisms, thereby completely eliminating the risk of secondary transmission.

[0011] The present invention implements two innovative measures to enhance the disinfection efficacy of the system: optimizing the exposure flux and increasing the irradiation intensity. By directing the microbial exposure path and improving internal reflection, the disinfection system achieves significantly improved efficacy.

[0012] In a first aspect, the present invention provides a portable and filter-free single-pass air disinfection system for disinfecting a contaminated airflow or a bioaerosol. The portable and filter-free single-pass air disinfection system comprises a disinfection chamber and one or more exhaust fans, wherein the one or more exhaust fans are mounted on one side of the disinfection chamber to promote airflow through the disinfection chamber. The disinfection chamber comprises a premixing zone, a processing zone, and a sampling zone. The premixing zone, the processing zone, and the sampling zone are interconnected. At least one partition is positioned between the premixing zone and the processing zone. The premixing zone comprises at least one air inlet, wherein the at least one air inlet is used to introduce the contaminated airflow or the bioaerosol into the disinfection chamber. The processing zone comprises an ultraviolet (UV) irradiation source, wherein the UV irradiation source is configured to irradiate the contaminated airflow or the bioaerosol in the disinfection chamber. The sampling zone comprises a liquid impinger connected to a vacuum pump for air sampling and at least one exhaust port for cleaning air.

[0013] In one embodiment, the partition is made of UV transparent material, and the length of the partition is shorter than the width of the sterilization chamber.

[0014] In one embodiment, the UV radiation source is a far-UVC source emitting light at a wavelength of approximately 222 nanometers, the far-UVC source comprising a tubular lamp or a rectangular lamp.

[0015] In one embodiment, the rectangular light is positioned outside the sterilization chamber.

[0016] In another embodiment, the tubular light is positioned inside the treatment component.

[0017] In one embodiment, said at least one baffle directs the flow of said contaminated airflow or said bioaerosol to extend the airflow path to an area with high UV radiation.

[0018] In one embodiment, the at least one partition and the inner wall of the sterilization chamber are covered with a reflective material having a reflectivity of at least 90% to enhance UV reflection, the reflective material comprising aluminum foil.

[0019] In one embodiment, the portable and filter-free single-pass air disinfection system has an airflow rate of at least 100 cubic meters per hour.

[0020] In one embodiment, the portable and filter-free single-pass air disinfection system is capable of inactivating pathogens in contaminated airflow or bioaerosols. The portable and filter-free single-pass air disinfection system has an inactivation rate of at least 80% for Salmonella enterica, an inactivation rate of at least 15% for Staphylococcus epidermidis, and an inactivation rate of at least 20% for MS2 bacteriophage.

[0021] In another embodiment, the portable and filter-free single-pass air disinfection system comprises an input terminal connected to a current input device for controlling the current of the one or more exhaust fans.

[0022] In one embodiment, the sterilization chamber is made of at least one acrylic plate having a thickness of 1 mm to 10 mm.

[0023] In a second aspect, the present invention provides a method for disinfecting a contaminated airflow or bioaerosol, the method comprising: preparing a filterless disinfection chamber having a premixing zone, a processing zone, and a sampling zone; introducing the contaminated airflow or the bioaerosol into the premixing zone; directing the contaminated airflow or the bioaerosol toward the processing zone; and collecting and analyzing irradiated air samples to determine microbial concentrations. At least one partition is inserted between the premixing zone and the processing zone. The processing zone includes a UV irradiation source configured to irradiate the contaminated airflow or the bioaerosol within the disinfection chamber, wherein the UV irradiation source includes a far-UVC source emitting light at a wavelength of about 222 nanometers.

[0024] In one embodiment, one or more exhaust fans are mounted on one side of the sterilization chamber to facilitate airflow through the sterilization chamber.

[0025] In one embodiment, the far-UVC source comprises a tubular lamp or a rectangular lamp. The rectangular lamp is positioned outside the disinfection chamber. The tubular lamp is positioned inside the treatment zone.

[0026] In one embodiment, the method further comprises covering the at least one partition and inner wall of the sterilization chamber with a reflective material having a reflectivity of at least 90% to enhance UV reflection.

[0027] In another embodiment, the method further comprises pre-sterilizing the disinfection chamber with UV light prior to introducing the contaminated airflow or the bioaerosol.

[0028] In yet another embodiment, the method further comprises installing a safety device to automatically shut down the UV radiation source when the sterilization chamber is opened during operation.

[0029] In yet another embodiment, the method further comprises calibrating the UV radiation source to ensure consistent irradiance levels within the sterilization chamber.

[0030] The present invention has the following advantages:

[0031] The inactivation efficacy of portable and filter-free single-pass disinfection systems has been significantly improved. By inserting baffles to direct airflow and enhance UV reflection, both the internal tube equipped (ITE) system and the external module equipped (EME) system have achieved significant efficacy improvements without the need for additional UV sources. With two original modifications, the EME system has an inactivation efficacy of 93.4% for Salmonella enterica, 51.8% for Staphylococcus epidermidis and 52.5% for MS2. Similarly, the ITE system has an inactivation efficacy of 97.6%, 54.4% and 55.1% for the same microorganisms, respectively. Both system configurations show high levels of inactivation efficacy, with an overall enhancement of at least 200%.

[0032] Compared to upper room UVGI installations, the portable and filter-free single-pass disinfection system provided 23.0% to 29.2% higher equivalent ACH in removing far-UVC resistant microorganisms, demonstrating the potential for use of the system in small spaces such as residences and private offices. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Embodiments of the present invention are described in more detail below with reference to the accompanying drawings, in which:

[0034] Figure 1 The layout of the sterilization chamber is shown. (Unit: mm). a = bioaerosol inlet, b = 1-3 = air inlet, c 1-2 = sampling point, d 1-2 =Exhaust fan;

[0035] Figure 2A The configuration of a basic EME disinfection system is shown. Figure 2B The configuration of a basic ITE disinfection system is shown;

[0036] Figure 3A The spectral distribution emitted by a rectangular lamp module is shown. Figure 3B The spectral distribution emitted by the tubular lamp is shown. Figure 3C shows the ozone concentration in the chamber relative to the operating time of the lamp;

[0037] Figure 4AA diagram of a modified EME disinfection system with bare bulkheads is shown. Figure 4B shows a diagram of a modified ITE disinfection system with bare bulkheads;

[0038] Figure 5A A top view of a modified EME sterilization system with an aluminum (Al) foil covered partition is shown. Figure 5B shows a top view of a modified ITE disinfection system with Al foil covered baffles;

[0039] Fig. 6A Shown is the UV irradiance distribution measured inside a basic EME system. Figure 6B The UV irradiance distribution measured inside the basic ITE system is shown. For each grid point, there are two numbers, the top number indicates the irradiance measured at Z = 75, and the bottom number indicates the irradiance measured at Z = 25 (unit: for UV irradiance, μW / cm 2 ; for dimensions, mm);

[0040] Figure 7A-7B Shown are the measured UV intensity distributions in the UV treatment sections of the modified EME and ITE systems. Fig. 7A Indicates the use of bare bulkheads, while Figure 7B Indicates the use of foil-covered separators;

[0041] Figure 8 The flow rates of the basic and improved EME / ITE systems are shown. (“√” means p value < 0.05, and “×” means p value > 0.05. Brackets indicate ITE system); and

[0042] Fig. 9A The inactivation efficacy of the basic and enhanced EME / ITE systems against Salmonella enterica is shown. Fig. 9B The inactivation efficacy of the basic and enhanced EME / ITE systems against Staphylococcus epidermidis is shown. Fig. 9C The inactivation efficacy of the basic and enhanced EME / ITE systems on MS2 is shown. DETAILED DESCRIPTION

[0043] In the following description, a portable and filter-free single-pass air disinfection system utilizing far-UVC sources of different form factors is described as a preferred example. It will be apparent to those skilled in the art that modifications including additions and / or substitutions may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscure the invention; however, this description is written to enable those skilled in the art to practice the guidance herein without undue experimentation.

[0044] Conventional air purifiers use filters to remove particulate matter and bioaerosols from indoor air, making them a popular choice due to their portability and reliable performance. However, viruses can be as small as tens of nanometers, requiring the use of HEPA filters to effectively capture the viruses. However, there are several disadvantages to using HEPA filters, such as HEPA filters cannot be cleaned and reused. In order to maintain the expected filtering performance of HEPA filters, the filters must be replaced regularly. In addition, HEPA filters are not only expensive but also considered to be disposable consumables, so filter-based air purifiers are considered to be an unsustainable product.

[0045] In a one-way air disinfection system, there may be two arrangements of the UV source. The first arrangement is an external arrangement, in which the lamp is positioned outside the system. In this setting, the irradiation passes through an opening or a transparent window to disinfect the airflow. The second arrangement is an internal arrangement, in which the lamp tube (usually a bare tube) is securely mounted in the air channel. The internal tube provides a wider UV coverage than the external lighting surface. On the other hand, the external UV source allows heat dissipation outside the system without affecting the airflow inside. Therefore, the present invention provides two air disinfection systems that use far-UVC sources of different configurations to disinfect indoor air. The disinfection system is portable, efficient, environmentally friendly, and has low operating and maintenance costs.

[0046] Two types of light sources:

[0047] The first system (referred to as the EME system) comprises a rectangular UV source module mounted on the outer surface of the disinfection chamber. In the basic EME system, air flows directly through the UV treatment section, which results in a lower dose of UV exposure. Moving the rectangular lamp to the opposite side may increase the exposure of the air to UV irradiation. However, because the airflow is perpendicular to the direction of the UV light, the exposure range will be limited by the narrow irradiation angle of the lamp.

[0048] The second system, known as the ITE system, integrates the UV tube centrally within the cabinet.

[0049] Additionally, additional baffles can be inserted to direct the contaminated air towards areas with high UV irradiance. This is also intended to extend the exposure time by increasing air resistance.

[0050] In one embodiment, the light source is a mercury-free, filtered 222 nm far-UVC tube.

[0051] Regarding far-UVC sources, 222 nm far-UVC is presented as a sustainable option with advanced emission technology and proven antimicrobial efficacy. In addition, 222 nm far-UVC is considered safer than 254 nm UVC due to limited skin penetration and minimal DNA absorption. The lifespan of a 222 nm UV source is longer than that of a HEPA filter. The recommended replacement cycle for air filters is 4 to 6 months, while the expected lifespan of a 222 nm UV lamp is more than 4,000 hours (8 hours of use per day for a total of 16 months). In addition, the cost of 222 nm UV lamps is constantly decreasing due to technological developments and manufacturing expansion.

[0052] To evaluate the air disinfection efficacy of the portable disinfection system, two bacteria (Salmonella enterica and Staphylococcus epidermidis) and one bacteriophage (MS2) were selected as challenges for the system operating at flow rates exceeding 100 m3 / h.

[0053] The basic EME system inactivated microorganisms with 81.4%, 16.9% and 25.1% efficacy against Salmonella enterica, Staphylococcus epidermidis and MS2, respectively. In contrast, the basic ITE system showed higher inactivation efficacy due to the wider irradiated area, with corresponding efficiencies of 94.4%, 25.8% and 37.8% for the tested microorganisms, respectively.

[0054] The air disinfection system contains some original features that improve pathogen exposure and UV light intensity, which can significantly enhance the disinfection efficacy of the system. Two enhancement measures were implemented by directing the airflow to areas with high UV irradiance and enhancing UV reflection, thereby increasing the inactivation efficacy of the system by at least 200%. When tested against Staphylococcus epidermidis, the modified EME and ITE systems showed an increase in inactivation rates of 23.0% and 29.2%, respectively, compared to upper room far-UVC. These results demonstrate the potential of portable disinfection systems to effectively and sustainably inactivate a broad spectrum of microorganisms.

[0055] In addition to enteric Salmonella, the portable disinfection system of the present invention can inactivate other Gram-negative bacteria, including but not limited to Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Neisseria gonorrhoeae, Haemophilus influenzae, Helicobacter pylori, Proteus mirabilis, Vibriocholerae, and Acinetobacter baumannii.

[0056] In addition to Staphylococcus epidermidis, the portable disinfection system of the present invention can inactivate other Gram-positive bacteria, including but not limited to Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Enterococcus faecalis, Bacillus anthracis, Listeria monocytogenes, and Corynebacterium diphtheriae.

[0057] In addition, the application of aluminum (Al) foil further improves the inactivation efficacy of the system by providing UV reflection. These modifications allow the EME system to achieve comparable or even superior inactivation efficacy compared to ITE systems while maintaining the same power consumption of the UV source.

[0058] Examples

[0059] Example 1 - Materials and Methods

[0060] Test microorganisms

[0061] In this example, Salmonella enterica (ATCC 53648), Staphylococcus epidermidis (ATCC 12228) and MS2 were selected as test microorganisms. Both Salmonella enterica and Staphylococcus epidermidis are commonly found in indoor environments and are widely used in disinfection experiments. Bacteriophage MS2 (a non-enveloped and single-stranded RNA virus) was tested as a surrogate for SARS-CoV-2 and influenza.

[0062] Preparation of test microorganisms

[0063] First, a colony of each strain grown on nutrient broth (NB; Difco) agar was inoculated into NB and incubated at 37°C for 24 hours to obtain a stationary growth phase. The bacteria were harvested by centrifugation at 6000 rpm (revolutions / minute) and suspended in 50 ml of 10% ethanol. 8 Up to 10 9 CFU (colony forming units) / mL in 0.9% saline for subsequent experiments.

[0064] MS2 is cultivated by double-layer agar method.First, Escherichia coli (E.Coli, ATCC 15597) (host of MS2) is grown in TSB (tryptone soy broth, Difoco) at 37 ℃ for 1 hour, to reach early logarithmic phase.Afterwards, 1 milliliter of overnight culture of E. coli is mixed with the suspension of 0.05 milliliter of MS2 mother liquor in 5 milliliters of fresh TSB.Then, bacteria-phage mixture is added to 45 ℃, 5 milliliters, 0.7% (wt / vol) of melting fresh soft TSA (tryptone soy agar, Difoco) and vortex mixed.After vortex mixing, the mixture is poured on 1.5% solid TSA plate, and it is solidified for 3 to 5 minutes. Subsequently, the plate is incubated at 37 ℃ for 24 hours. The soft agar on the overnight plate is scraped off with a disposable applicator, and is resuspended in 25 milliliters of 0.9% saline. The suspension was centrifuged at 6000 rpm for 15 minutes to remove cells and debris. The supernatant was filtered through a 0.22 μm polyethersulfone (PES, Millipore) membrane and kept at 4°C until further study. The final concentration of the MS2 solution was 10 11 Up to 10 12 plaque forming units (PFU) / ml.

[0065] Example 2 - Preparation of a portable and filter-free single-pass disinfection system

[0066] All systems contain three necessary hardware components: a disinfection chamber, a UV source, and two exhaust fans. The chamber, which measures 550 mm x 300 mm x 150 mm (X, Y, Z), is made of a 5 mm thick acrylic sheet, which is transparent but has almost zero penetration of far-UVC light. Figure 1 The longitudinal sections of the chamber are depicted along with detailed dimensions. The chamber is divided into three sections: pre-mixing section (X range 0 to 100 mm), UV treatment section (X range 100 mm to 400 mm) and sampling section (X range 400 mm to 550 mm).

[0067] refer to Figure 1 , the microorganisms are atomized and injected into the chamber from position a. At the same time, the room air passes through three circular openings b. 1-3 Suctioned into the chamber, the diameter of each circular opening is 40 millimeters.Inside the chamber, air and microorganisms are mixed in the premixed section formed by using acrylic plate to divide the chamber, and then enter the UV treatment section.Although the atomized microorganisms are effectively mixed with air flow during the air flow passes through these sections, the atomized microorganisms may be unevenly distributed in the sampling section.In view of the presence of two air flow outlets in the chamber, air samples are collected from c1 and c2 near the outlet respectively.These samples are combined to determine the concentration of the microorganisms present in the system.Two axial flow fans (Delta company (Delta), AFC1212D) are installed at position d1, d2, to draw air flow through the chamber.The rated air flow rate of each fan is 148CFM (248.64 cubic meters / hour).

[0068] In this example, two different krypton chloride far-UVC sources were used separately in the UV treatment section. The first source was a rectangular lamp module (15W, Care 222, Ushio, Japan), and the second source was a tubular lamp (20W, First UVC, China). These lamps were equipped with optical filters that removed all other emission wavelengths except 222 nanometers. Figure 2A-2B Shown are schematic diagrams of two systems in their basic configuration, which serve as a benchmark for comparison.

[0069] The spectral distribution and O3 generation of both lamps were measured and recorded in Figures 3A-3CBoth lamps had peak emission at 222 nanometers with a full width at half maximum (FWHM) of 4 nanometers. The concentration of O3 produced was measured by an O3 monitor (Model 205, 2B Technologies) inside the chamber near the UV source in the absence of airflow. Both lamps produced minimal O3 during illumination at concentrations several times lower than the US Environmental Protection Agency standard of 70 ppb34. Additionally, the measured concentrations were significantly lower than 2300 ppb, at which O3 would exhibit antimicrobial properties and cause extensive cell death35. It should also be noted that operation of the lamps did not cause a significant increase in airflow temperature during the experiment.

[0070] In order to prevent far-UVC from directly irradiating the premixing section and to facilitate the installation of subsequent baffles for directional airflow, a rectangular lamp module is installed in a position outside the disinfection chamber (X=175 mm, Y=300 mm, Z=75 mm). The chamber is characterized in that the opening is measured to be 50 mm×70 mm, which is perfectly aligned with the lighting window of the lamp module, so that UV irradiation can enter the chamber. This configuration is called an ITE system. In another system equipped with a tubular lamp, a far-UVC tube with a diameter of 30 mm and a height of 120 mm is centered at a certain position (X=250 mm, Y=150 mm). A base with a height of 1.5 cm is used to fix the tube. This configuration is called an EME system.

[0071] refer to Figure 4A-4B , additional acrylic panels can be installed inside the chamber. These partitions are strategically positioned to direct the contaminated air to areas with high-intensity UV irradiation. In the EME system, two additional acrylic panels are installed at X=250 mm and X=400 mm. The panel at X=250 mm is designed to direct the contaminated air to areas with high UV irradiance, while another panel at X=400 mm is added to further increase the exposure time by creating additional air resistance. In the ITE system, only one additional panel is installed at X=400 mm. This additional panel is also intended to direct the airflow to the high-intensity zone. The airflow blockage is further adjusted by the panel length of the partition. In the following example, two panel lengths were tested: 200 mm and 250 mm.

[0072] The second enhancement involves covering portions of the interior and bulkhead walls with UV reflective material to enhance inter-wall reflection and further increase UV irradiance. Figure 5A-5B, the inner wall and the partition wall around the far UVC lamp are covered with Al foil to enhance UV reflection, thereby further increasing UV irradiance. In the EME system, the partition at X = 400 mm is not covered with Al foil because UV light cannot penetrate the partition at X = 250 mm to reach the board.

[0073] Example 3 - Process

[0074] In order to prevent external environmental interference, the experiment was carried out in an airtight chamber with a leakage less than 0.1ACH (air changes / hour). During the experiment, the air in the room was maintained at approximately 20°C and a relative humidity of 58%. Before each experiment, the disinfection system to be tested was sterilized with 70% ethanol, and the room was pre-disinfected with a 36W 254 nanometer UV lamp for 15 minutes. Once pre-disinfection is completed, the O3 concentration is rapidly reduced within 2 minutes and cannot be detected by the O3 monitor. Subsequently, the suspension of the pathogen is atomized and injected into the system by a 6-jet atomizer (CH Technologies, USA) with an air pressure of 20psi (137.9kPa) provided by an air compressor. In order to minimize the dispersion of microorganisms by the discharged air, the indoor air purifier is positioned near the chamber outlet to collect the discharged microorganisms. Wait for ten minutes to ensure that the bioaerosol concentration inside the system reaches a stable level. Then air samples are collected to study the concentration level of the microorganisms in the chamber. A liquid impinger (Biological Sampler, SKC, USA) filled with 20 ml of 0.9% saline was connected to a vacuum pump with a flow rate of 12.5 liters / minute for air sampling. A flexible tube was connected from the impinger sampling opening to point c1. In addition, a 3 cm long tube was attached to the inner part of c1 and extended into the chamber, allowing air to be sampled from the mainstream. After sampling at c1 for 2 minutes, the liquid impinger was connected to point c2, and finally the results were combined to determine the microbial concentration under UV off conditions. The sampling flow rate was maintained at 12.5 liters / minute by a vacuum pump. Next, the far-UVC lamp was turned on and the above procedure was repeated to study the disinfection performance of the far-UVC treatment.

[0075] After air sampling, a series of 10-fold dilutions were performed, followed by plate culture. For airborne bacteria, 50 μL of diluted samples were evenly spread on solid NA plates, and the plates were then incubated at 37°C for 24 hours. After incubation, the resulting CFU on the plate were counted for further study. For viruses, 50 μL of diluted samples were mixed with 3 milliliters of molten 0.7% TSA and 50 μL of logarithmic phase E. coli. The mixture was then vortexed and evenly distributed on 1.5% solid TSA plates. After incubation at 37°C for 24 hours, the PFU on the plate were counted.

[0076] The two base systems were initially tested for their inactivation efficacy against three microorganisms, respectively, to establish a baseline. Subsequently, enhancements were implemented sequentially for further study. For each experiment, only one air sampling was performed. All experiments were repeated at least three times. Additionally, bioaerosol survival can be affected by many environmental factors. To account for natural losses and potential harm caused by atomization and / or impactor collection, control experiments were performed without far-UVC treatment. These control experiments were used as comparisons to evaluate the effectiveness of far-UVC treatment in reducing microbial concentrations.

[0077] Example 4 - UV irradiance distribution of a portable and filterless single-pass disinfection system

[0078] A high-resolution fiber optic spectrometer (ULS3648, Avantes, Netherlands) was used to measure spatial far-UVC irradiance. Since the optical sensor of the spectrometer only measures the unidirectional irradiance of the plane, the UV irradiance is measured from six orthogonal directions at each measurement point, and then combined to determine the total UV irradiance received by the microorganism at the specific point. The volume-average UV irradiance is determined by averaging all the measured values ​​in the irradiated area.

[0079] Since far-UVC light cannot penetrate the acrylic plate, the UV irradiance from X=0 to X=100 in the premixing section is assumed to be negligible. Due to the balanced positioning of the UV source in the chamber, the expected UV irradiance distribution is symmetrical about the Z=75 mm plane. Therefore, the UV irradiance distribution in the chamber is measured at Z=25 mm and Z=75 mm to calculate the volume-average UV irradiance. In addition, due to the symmetrical layout of the ITE system, the irradiance measurement results are further simplified. The inner area from X=100 mm to X=550 mm is divided into four quadrants by a UV tube located at a certain point (X=250 mm, Y=150 mm). The irradiance distribution in the first quadrant is first measured and then used to determine the spatial UV irradiance in other quadrants. Since the optical sensor of the spectrometer only measures the unidirectional irradiance of the plane, the UV irradiance is measured from six directions at each measuring point, and then summed to calculate the total irradiance received by the microorganism at the point. 24 The volume-average UV intensity was determined by averaging all measured values.

[0080] Due to the symmetrical layout of the system and UV sources, the intensity distribution above the midplane (Z=75) is assumed to be a mirror image of the lower counterpart. In this regard, the intensity distribution in the Z=125 plane is assumed to be equal to the intensity distribution in the Z=25 plane. In addition, the inner region from X=100 to X=550 is divided into four quadrants by the UV tube located at a certain point (X=250, Y=150). The intensity distribution in the first quadrant is first measured and then used to determine the distribution in the other three quadrants.

[0081] Figure 6A-6B Detailed measurements of the UV irradiance distribution in basic EME and ITE systems are presented. In the EME system, only about half of the chamber volume receives UV irradiation due to the small size of the illuminated surface and the limited beam angle of the rectangular modules. The volume-averaged UV irradiance over the entire chamber in the basic EME system was determined to be 37.4 μW / cm 2 In contrast, the basic ITE system can evenly irradiate the entire chamber and has a significantly expanded internal UV-irradiated area with an average irradiance of 56.0 μW / cm 2 .

[0082] By inserting additional baffles, the UV treatment section is divided into several semi-enclosed areas, so that the original airflow is changed. The purpose of these baffles is to direct the airflow towards areas with high-intensity UV irradiation instead of areas with relatively low UV irradiance. Figure 7A-7B As shown, the segmented EME system ( Fig. 7A a1) As an example, the airflow is directed to point A2, where the UV irradiance is measured to exceed 300 μW / cm 2 The volume-average UV irradiance of the segmented EME system in this irradiated area was 105.0 μW / cm 2 . Similarly, for ITE systems ( Fig. 7A , b1), the volume-average UV irradiance in the irradiated area is 74.7 μW / cm 2 When the partitions are extended to 250 mm, it is expected that the spatial UV irradiance will remain consistent.

[0083] refer to Figure 7B When Al foil is coated, the average irradiance in the UV-irradiated area increases to 117.8 μW / cm for the EME system (a2) and ITE system (b2), respectively. 2 and 100.8μW / cm 2. The enhancement rates of the EME and ITE systems are 12.2% and 34.9%, respectively. The relatively low enhancement effect of the EME system can be attributed to the arrangement of the partitions and lamps. Because the partitions in the EME system are arranged parallel to the UV light emitted by the external lamps, the partition surfaces close to the UV lamps receive the least amount of direct irradiation. This configuration results in limited UV light reflected from the partitions. As shown in a1 and a2, when the Al foil is applied, the measured UV irradiance at points A1, B1, and C1 increases slightly. However, the aluminum foil on the wall opposite to the lamp reflects UV light, thereby significantly increasing the irradiance near the reflective surface. For example, after applying the aluminum foil, the UV irradiance measured at all points on row E increased by at least 50%.

[0084] Example 5 - Flow Rates for a Portable Filterless Single Pass Disinfection System

[0085] The flow rate of the tested embodiment (with or without internal baffles) was measured by a vane anemometer (model 417, Testo) near the system outlet. An additional accessory of the anemometer can be used to collect the total airflow discharged by the system, which is then passed through the anemometer for measurement. The measurement for each configuration of the system lasts for 90 seconds. The measured flow rate is recorded every 30 seconds and finally averaged.

[0086] Figure 8 The airflow rates for systems with various baffle configurations are shown in Figure 1. Based on these measurements, the Reynolds number for the airflow within the system ranged from 8842 to 13379, indicating that the airflow was turbulent. The base EME and ITE systems exhibited comparable airflow rates (125.3 m3 / hr vs. 126.7 m3 / hr), indicating that the air resistance caused by the internal UV tube was not significant.

[0087] By installing an additional 200 mm long baffle (200 mm P group), the EME system airflow rate decreased by 17.2%, while the ITE system airflow rate showed a modest but statistically insignificant decrease of less than 10%. The difference in flow rate decreases indicates the effect of the second baffle. Extending the baffle length to 250 mm (250 mm P group) resulted in only a slight and statistically insignificant decrease in airflow rate compared to the 200 mm long baffle (decreases of 3.9% and 9.8%, respectively).

[0088] In addition, the airflow rate of the tested embodiment is mainly controlled by the input current of the axial fan and the air resistance caused by the number of partitions and the degree of airflow obstruction. Two input current settings were tested, with a rated current of 1.6A for each fan (3.2A for both fans) and a minimum current of 0.9A for stable fan operation (1.8A for both fans). Taking the ITE system as an example, the airflow rate at different currents and partition lengths was measured, and the results are listed in Table 1. The flow rate of the tested embodiment is reduced due to the 200 mm partition. By extending the partition to 250 mm, the flow rate is further reduced.

[0089] Table 1 - Flow rates in ITE systems with different fan currents and baffles. (Unit: cubic meters per hour)

[0090] Example 6 - Microbial inactivation efficacy

[0091] The disinfection efficacy of the system is calculated by equation (1). Where C1( / m 3 ) and C2( / m 3 ) is the concentration of airborne microorganisms during the two sampling periods, and the ratio of these concentrations represents the surviving fraction of microorganisms that have been treated by the system.

[0092] Since the duration of both samplings was the same, the concentration term in the equation was replaced by the CFU or PFU counted on the agar plates used to culture the microorganisms collected from the sampled air, regardless of whether they had been treated with far-UVC.

[0093] η' is the concentration decrease between two sampling periods caused by other natural or environmental factors. During the control experiment, when the UV is off, η' can be calculated as: η′=1-C 2,off / C 1,off ×100% (2) Among them C 2,off and C 1,off is the concentration of airborne microorganisms in the system with far-UVC turned off. A two-tailed paired t-test was applied to determine significant differences between the disinfection efficacies obtained from the different scenarios. Statistical significance was demonstrated by p-value < 0.05.

[0094] Based on the control test, the obtained η' was 0.57% ± 0.04. This value indicates that the influence of non-UV factors on the experimental results is negligible.

[0095] Figures 9A-9C The inactivation efficacy of two basic systems and the impact of modifications are shown. The inactivation efficacy is obtained by averaging at least three sets of experimental data. In the basic EME system, the inactivation efficacy for Salmonella enterica, Staphylococcus epidermidis and MS2 is 81.4%, 16.9% and 25.1% respectively. On the other hand, the basic ITE system shows a higher efficacy for the same microorganisms, with values ​​of 94.4%, 25.8% and 37.8%. The difference in inactivation efficacy between the basic EME and ITE systems is 16.0%, 53.1% and 50.3% respectively. The difference can be attributed to the wider irradiation area and higher power output of the UV lamp in the ITE system.

[0096] The relationship between the output of the UV lamp and the inactivation efficacy of the system follows the Bunsen-Roscoe reciprocity law, as described by the equation: 1-η=e -Z*D =e -Z*I*t (3) Where Z(m 2 / J) is the far-UVC sensitivity constant of microorganisms; D (J / m 2 ) is the UV radiation dose received by the microorganism, which is the average UV irradiance (I, W / m 2 ) multiplied by the UV exposure time (t, seconds).

[0097] The estimated inactivation efficacy of the basic ITE system equipped with a 15W UV tube for the three tested microorganisms was 91.9%, 22.9% and 33.8%. These values ​​are 12.9%, 35.7% and 34.7% higher than the inactivation efficacy of the basic EME system for Salmonella enterica, Staphylococcus epidermidis and MS2, respectively. This shows the beneficial effect of the tubular geometry of the UV source in the basic system.

[0098] In addition, compared with the basic system, the installation of an additional 200 mm long partition improves the inactivation efficacy. The EME system shows a slight improvement of 6.5% in the inactivation efficacy of Salmonella enterica, while the ITE system shows an improvement of 2.2%. However, the survival score (1-η) of Salmonella enterica is significantly reduced. In the EME system, the survival score drops from 18.6% to 13.3%, corresponding to a decline rate of 28.4%. Similarly, in the ITE system, the survival score drops from 5.6% to 3.5%, wherein the decline rate is 36.6%. The inactivation efficacy of Staphylococcus epidermidis and MS2 shows impressive improvements: 43.5% and 38.7% for the EME system, and 37.7% and 20.6% for the ITE system. However, the improvement of the ITE system in inactivating airborne MS2 is not statistically significant, with a p value of =0.13. When the length of the partitions was extended to 250 mm, the system showed a modest but statistically non-significant improvement in inactivation efficacy compared to a system equipped with 200 mm long partitions.

[0099] Compared with the extension of the baffle, the application of Al foil significantly improves the inactivation efficacy. For the EME system equipped with a 200 mm baffle, the application of Al foil enhances the inactivation efficacy of Salmonella enterica, Staphylococcus epidermidis and MS2 to 93.4%, 51.8% and 52.5%, respectively. The enhancement rates are 7.7%, 113.9% and 50.7%, respectively. For the ITE system, the inactivation efficacy of the three microorganisms is improved to 97.6%, 54.4% and 55.1%, wherein the enhancement rates are 1.2%, 53.0% and 21.0%, respectively. The power of the UV tube is reduced to 15W, and based on equation (3), the inactivation efficacy of the modified ITE system for the three microorganisms is estimated to be 96.1%, 49.5% and 50.2%.

[0100] Example 7 - Air disinfection performance of disinfection system

[0101] In previous studies, under well-mixed air conditions, in an atmosphere with 11.9 m 3 The air disinfection efficacy of the upper room far-UVC fixture was tested in a volume room 10 In this example, it is assumed that both the EME system and the ITE system are used in the same room and both systems are operated under well-mixed air conditions to compare the disinfection performance of the proposed portable air disinfection system with that of the wall-mounted upper-room far-UVC fixture.

[0102] The reduction in the concentration of airborne microorganisms attributable to the disinfection system under well-mixed conditions can be determined based on a mass balance: Where Q is the airflow rate handled by the system (m3 / h); C is the indoor bioaerosol concentration ( / m 3 ), and C0 is the initial concentration ( / m 3 ); t is the operating duration of the system (hours); V is the volume of the room (m 3 ). At the same time, k(hr -1 ) is the decay rate of bioaerosol concentration caused by UV inactivation. When expressed in hr -1 When expressed in units, it is equivalent to the concept of ACH.

[0103] In this semi-hypothetical scenario for indoor air disinfection, an EME or ITE system is applied, which is modified with a 200 mm partition covered with aluminum foil. The equivalent ACH provided by the system can be estimated using equation (4) and compared with the results from previous studies on upper room far-UVC, as shown in Table 2. The power consumption of the UV sources used in this calculation is all set to 15W, which is the power consumption of the far-UVC lamp used in the upper room experiment. Therefore, based on equation (3), the inactivation efficacy of the modified ITE system with 20W power far-UVC tube is adjusted to the inactivation efficacy of the system with 15W power.

[0104] Table 2 - Equivalent ACH (hr) of microbial inactivation by far-UVC in disinfection systems and upper rooms -1 ) 10 Salmonella enterica Staphylococcus epidermidis MS2 EME System 8.14 4.52 4.58 ITE System 9.21 4.74 4.80 Upper Room Far UVC 28.44 3.67

[0105] In Table 2, the EME and ITE disinfection systems performed better in removing S. epidermidis with ACHs of 23.0% to 29.2% higher, respectively, compared to the upper room far-UVC system. However, it should be noted that these disinfection systems showed significantly slower inactivation of S. enterica compared to the upper room installation, by nearly 20 hours. -1 . This suggests that upper room far-UVC installations have an advantage in disinfecting microorganisms that are highly sensitive to far-UVC light, while portable disinfection systems perform better in inactivating far-UVC-resistant microorganisms. This is because the systems are able to provide higher UV irradiance in localized areas, thereby improving air disinfection effectiveness. In practical applications, air contains a variety of microorganisms that need to be inactivated, not just a single type. Since the duration of the disinfection process is often determined by the presence of UV-resistant microorganisms, the high inactivation efficacy of these systems against such microorganisms is a clear advantage compared to upper room UVGI.

[0106] In summary, the present invention provides a single-pass air disinfection system using far-UVC irradiation. The system has been evaluated for inactivation of bacteria (including Salmonella enterica, Staphylococcus epidermidis, and bacteriophage MS2) at high flow rates exceeding 100 m3 / h. The significant non-uniform distribution of UV irradiance produced by the rectangular lamp is a key factor that leads to the poorer disinfection performance of the basic EME system compared to the ITE system.

[0107] The foregoing description of the present invention has been provided for the purpose of illustration and description. The foregoing description is not intended to be exhaustive or to limit the invention to the precise form disclosed. For those skilled in the art, many modifications and variations will be apparent.

[0108] The embodiment was chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated.

[0109] definition

[0110] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising" should be understood to imply the inclusion of the stated integer or groups of integers, but not the exclusion of any other integer or groups of integers. It should also be noted that in this disclosure and particularly in the claims and / or paragraphs, terms such as "comprises", "comprised", "comprising" and the like may have the meaning ascribed to them in U.S. patent law, such as to allow for elements not expressly recited, but to exclude elements found in the prior art or elements that affect the basic or novel characteristics of the invention.

[0111] Furthermore, throughout the specification and claims, unless the context requires otherwise, the word "include" or variations such as "includes" or "including", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0112] As used herein and not otherwise defined, the terms "substantially," "essentially," "approximately," and "about" are used to describe and explain small variations. When used in conjunction with an event or circumstance, the terms may encompass instances where the event or circumstance occurs precisely as well as instances where the event or circumstance nearly occurs. For example, when used in conjunction with a numerical value, the terms may encompass a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.

[0113] References in this specification to "one embodiment", "an embodiment", "example embodiment", etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is considered to be within the knowledge of those skilled in the art to affect such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0114] In the preparation method described herein, except for the case of explicitly describing the time or operation sequence, the steps can be performed in any order without departing from the principles of the present invention. The description of performing a certain step first and then performing several other steps subsequently in a certain claim should be considered to mean that the first step is performed between any other steps, but the other steps can be performed in any suitable order unless the order is further described in other steps. For example, the claim element describing "step A, step B, step C, step D and step E" should be interpreted as meaning that step A is performed first and step E is performed last, and steps B, C and D can be performed in any order between step A and step E, and the order still falls within the literal scope of the process claimed for protection. A given step or a subset of steps can also be repeated. In addition, unless the clear claim language describes that the specified steps are performed separately, the specified steps can be performed simultaneously.

[0115] The term "single pass" refers to a process where an airflow or bioaerosol passes through the disinfection system only once to achieve the desired disinfection level. This means that the air only needs to pass through the system once to be effectively disinfected, without the need for multiple passes or additional filtration stages. This design is intended to enhance disinfection efficiency while simplifying the system and reducing operating costs.

[0116] The term "pathogen" refers to a biological agent that causes disease or illness in its host. Pathogens include a variety of microorganisms, such as bacteria, viruses, fungi, and parasites. Pathogens can invade and multiply in the host, often triggering an immune response and causing a variety of symptoms or health problems.

[0117] The term "contaminated airflow" refers to an airflow that contains pollutants, harmful microorganisms, or other undesirable substances. These pollutants can include dust, bacteria, viruses, mold spores, chemical vapors, and other airborne particles that may pose a health risk or negatively affect indoor air quality. In environments such as hospitals, laboratories, industrial settings, and residential areas, managing contaminated airflow is critical to ensuring a safe and healthy atmosphere.

[0118] The term "bioaerosol" refers to a dispersion of tiny biological particles suspended in the air, including bacteria, viruses, fungal spores, pollen, animal dander and other microorganisms or their metabolites. These particles usually come from the natural environment such as soil, plants and water, as well as human activities such as agriculture, industry and medical facilities.

[0119] "High airflow rate" refers to the volume of air that moves through a given space or system in a specific period, usually measured in units such as cubic feet per minute (CFM) or liters per second (L / s). High airflow rate indicates that a large amount of air is being circulated or exchanged quickly. For example, a high airflow rate can be considered to be at least 100 cubic meters per hour (m3 / h). 3 / h).

[0120] Other definitions of selected terms used herein may be present in the detailed description of the present invention and are applicable throughout the text. Unless otherwise defined, all other technical terms used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the present invention belongs. Industrial Applicability:

[0121] The present invention enhances the efficacy of single-pass air disinfection in a portable disinfection system by adopting various far-UVC light sources. It has low initial cost, low operating cost and long life. The system design encloses the UVGI unit in the air chamber, effectively avoiding direct exposure of the occupants to ultraviolet radiation. Therefore, the system can be used even when there are occupants in the room. At the same time, through the modifications mentioned above, the system can maintain excellent disinfection efficiency even at high airflow rates. Therefore, it is expected that the system can provide continuous and reliable air disinfection for indoor occupants.

[0122] The present invention improves the portable single-pass disinfection system, focusing on improving its disinfection performance. These improvements are based on two original concepts: (i) redirecting the contaminated airflow, and (ii) enhancing the internal UV irradiance.

[0123] The portability of the system enables it to be applied to a variety of different scenarios and has wide versatility. The system can be used not only for room disinfection but also for public transportation. The system can be used as a standalone air disinfection system or combined with existing technologies to further reduce the concentration of airborne pathogens.

[0124] References: The disclosures of the following references are incorporated by reference. 1. Nazarenko, Y. (2020). Air filtration and SARS-CoV-2. Epidemiology and health, 42. 2. Lu, Z., Lu, W. Z., Zhang, J. L. and Sun, DX (2009). Microorganisms and particles in AHU systems: Measurement and analysis. Building and Environment, 44(4), 694-698. 3. Lee, LD, Delclos, G., Berkheiser, ML, Barakat, MT, and Jensen, PA (2022). Evaluation of multiple fixed in-room air cleaners with ultraviolet germicidal irradiation, in high-occupancy areas of selected commercial indoor environments. Journal of Occupational and Environmental Hygiene, 19(1), 67-77. 4. Burdack-Freitag, A., Buschhaus, M., Grün, G., Hofbauer, W. K., Johann, S., Nagele-Renzl, A. M., ... and Scherer, C. R. (2022). Particulate Matter versus Airborne Viruses—Distinctive Differences between Filtering and Inactivating Air Cleaning Technologies. Atmosphere, 13(10), 1575. 5. Burdack-Freitag A, Buschhaus M, Grün G, et al. Particulate matter and airborne viruses: stark differences between filtration and inactivation air purification technologies. Atmosphere. 2022;13:1575. 6. Snelling, W. J., Afkhami, A., Turkington, H. L., Carlisle, C., Cosby, S. L., Hamilton, J. W., ... and Dunlop, P. S. (2022). Efficacy of single pass UVC air treatment for the inactivation of coronavirus, MS2 coliphage and Staphylococcus aureus bioaerosols. Journal of Aerosol Science, 164, 106003. 7. Nunayon, SS, Zhang, HH, and Lai, AC (2020). A novel upper-room UVC-LED irradiation system for disinfection of indoor bioaerosols under different operating and airflow conditions. Journal of hazardous materials, 396, 122715. 8. Nunayon, SS, Zhang, H. and Lai, AC (2020). Comparison of disinfection performance of UVC-LED and conventional upper-room UVGI systems. Indoor Air, 30(1), 180-191. 9. Kim, DK and Kang, DH (2018). UVC LED irradiation effectively inactivates aerosolized viruses, bacteria, and fungi in a chamber-type air disinfection system. Applied and environmental microbiology, 84(17), e00944-18. 10. Nunayon, SS, Zhang, HH, Chan, V., Kong, RY and Lai, AC (2022). Study of synergistic disinfection by UVC and positive / negative airions for aerosolized Escherichia coli, Salmonella typhimurium, and Staphylococcus epidermidis in ventilation duct flow. Indoor Air, 32(1), e12957.

Claims

1. A portable, filter-free, one-way air disinfection system, characterized in that: The portable and filter-free one-way air disinfection system comprises: A disinfection chamber, comprising: a premixing zone, wherein the premixing zone comprises at least one air inlet for introducing a contaminated gas stream or a bioaerosol into the sterilization chamber; an ultraviolet (UV) treatment zone, wherein the UV treatment zone includes a UV radiation source configured to irradiate the contaminated airflow or the bioaerosol within the disinfection chamber; and a sampling zone, wherein the sampling zone comprises a liquid impinger connected to a vacuum pump for air sampling and at least one exhaust port for clean air; and one or more exhaust fans mounted on one side of the sterilization chamber to facilitate airflow through the sterilization chamber, wherein the premixing zone, the UV treatment zone and the sampling zone are connected to each other, At least one partition is positioned between the premixing zone and the processing zone.

2. The portable and filter-free single-pass air disinfection system according to claim 1, wherein the UV radiation source is a far-UVC source emitting light at a wavelength of approximately 222 nanometers, the far-UVC source comprising a tubular lamp or a rectangular lamp.

3. A portable and filter-free single-pass air disinfection system according to claim 2, wherein the rectangular light is positioned outside the disinfection chamber.

4. A portable and filter-free single-pass air disinfection system according to claim 2, wherein the tubular light is positioned inside the treatment component.

5. The portable and filter-free single-pass air disinfection system according to claim 1, wherein the at least one baffle directs the flow of the contaminated airflow or the bioaerosol to extend the airflow path to an area with high UV radiation.

6. The portable and filter-free single-pass air disinfection system of claim 1, wherein the at least one partition and inner wall of the disinfection chamber are covered with a reflective material having a reflectivity of at least 90% to enhance UV reflection, the reflective material comprising aluminum foil.

7. The portable and filter-free one-way air disinfection system according to claim 1, wherein the airflow rate of the portable and filter-free one-way air disinfection system is at least 100 cubic meters per hour.

8. The portable and filter-free single-pass air disinfection system according to claim 7, wherein the portable and filter-free single-pass air disinfection system inactivates pathogens in the contaminated airflow or the bioaerosol.

9. The portable and filter-free single-pass air disinfection system according to claim 7, wherein the portable and filter-free single-pass air disinfection system has an inactivation rate of at least 80% against enteric Salmonella, an inactivation rate of at least 15% against Staphylococcus epidermidis, and an inactivation rate of at least 20% against MS2 bacteriophage.

10. The portable and filter-free one-way air disinfection system according to claim 1, further comprising an input terminal connected to a current input device for controlling the current of the one or more exhaust fans.

11. The portable and filter-free single-pass air disinfection system according to claim 1, wherein the disinfection chamber is made of at least one acrylic plate having a thickness of 1 mm to 10 mm.

12. A method for disinfecting a contaminated gas stream or bioaerosol, wherein the method comprises the following steps: preparing a filterless sterilization chamber having a premixing zone, a processing zone, and a sampling zone, wherein at least one partition is interposed between the premixing zone and the processing zone; introducing the contaminated gas stream or the bioaerosol into the premixing zone; directing the contaminated airflow or the bioaerosol toward the treatment zone, wherein the treatment zone includes a UV radiation source configured to irradiate the contaminated airflow or the bioaerosol within the disinfection chamber, wherein the UV radiation source includes a far-UVC source emitting light at a wavelength of approximately 222 nanometers; as well as Irradiated air samples were collected and analyzed to determine microbial concentrations.

13. The method of claim 12, wherein one or more exhaust fans are mounted on one side of the sterilization chamber to facilitate airflow through the sterilization chamber.

14. The method of claim 12, wherein the far-UVC source comprises a tubular lamp or a rectangular lamp.

15. The method of claim 14, wherein the rectangular light is positioned outside the sterilization chamber.

16. The method of claim 14, wherein the tubular lamp is positioned inside the processing zone.

17. The method of claim 12, further comprising the step of covering the at least one partition and inner wall of the sterilization chamber with a reflective material having a reflectivity of at least 90% to enhance UV reflection.

18. The method of claim 12, wherein the method further comprises the step of pre-sterilizing the sterilization chamber with UV light prior to introducing the contaminated airflow or the bioaerosol.

19. The method of claim 12, wherein the method further comprises the step of installing a safety device to automatically shut down the UV radiation source when the sterilization chamber is opened during operation.

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