Capturing and analyzing aerosols and related devices, systems, and methods

Abstract

A system for capturing particles and analyzing material of the particles in an aerosol, the particles having a size within the range of 0.01 μm to 10 μm, includes a collector, a pump, an analyzer, and a release component. The collector is operable to trap a plurality of particles suspended in a fluid, the particles having a size ranging from 0.01 μm to 10 μm. The pump is operable to move the fluid containing the plurality of particles through the collector. The analyzer is releasably coupled with the collector and is operable to analyze material of the trapped particles. The release component is operable to release material of the trapped particles from the collector.

Description

[0001] CAPTURING AND ANALYZING AEROSOLS

[0002] AND RELATED DEVICES, SYSTEMS, AND METHODS

[0003] STATEMENT OF FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0004] [1] This invention was made with partial government support under DoD STTR Phase I (W911 SR-24-C-0004) grant. The government has certain rights in the invention.

[0005] CROSS-REFERENCE TO RELATED APPLICATIONS

[0006] AND INCORPORATION BY REFERENCE

[0007] [2] This application claims priority from U. S. Provisional Patent Applications 63 / 753,312 filed 3 February 2025 and titled “BROAD RANGE AEROSOL AND VAPOR COLLECTORS FOR CHEMICAL ANALYSES”; 63 / 822,877 filed 13 June 2025 and also titled “BROAD RANGE AEROSOL AND VAPOR COLLECTORS FOR CHEMICAL ANALYSES”; and 63 / 972,503 filed 30 January 2026 and titled “AEROSOL COLLECTORS FOR MICROSENSORS”. This application also incorporates by this reference the entirety of each of these U. S. Provisional Patent Applications.

[0008] BACKGROUND

[0009] [3] An aerosol is a suspension of fine solid particulates and / or liquid droplets in a fluid, such as air. Examples of an aerosol include airborne toxic chemicals, biological agents, radiological particles, nuclear particles, and particles of explosive remnants. Aerosols are typically categorized based on particle size into coarse, fine, and ultrafine fractions. Coarse aerosols generally include particles larger than 2.5 micrometers (pm). Examples of a coarse aerosol include dust, pollen, sea salt spray, and some spores. Fine aerosols generally include particles ranging between 0.1 pm and 2.5 pm.

[0010] Examples of a fine aerosol include biological material such as bacteria, spores, and virus clusters, dust particles, and particles from abrasion processes. Ultrafine aerosols generally include particles smaller than 0.1 pm, or 100 nanometers (nm). Examples ofan ultrafine aerosol include products of combustion, such as wildfires, traffic emissions, and aircraft emissions.

[0011] [4] Knowing the identity of particulates suspended in air or some other gas is very desirable to those who are, or are about to be, exposed to such an aerosol. Examples of such people include firefighters, military personnel, and / or the general public located near an accident and / or natural disaster. Knowing the particulates in an aerosol can allow one to take measures to mitigate or prevent one’s exposure to the particulates, and / or gain an understanding of the source of the aerosol.

[0012] [5] This is especially true when the particulates of an aerosol can be identified within a few minutes, if not in real time. Unfortunately, real-time, in-the-field, identification of many particulates is difficult, especially particulates whose size is 10 pm or less. A challenge with particulates at these sizes is collecting them. Often such collection devices are too large and bulky to be efficiently carried by an individual in the field. This is because the collection device has to collect a sufficient number of particles to allow the device that will analyse the particles to perform a reliable analysis. For aerosols with low particulate concentration, the collection device has to process a large volume of aerosol. Another challenge with particulates 10 pm and less in size is that their chemical identification often requires mass spectrometry (MS) or a combination of gas or liquid chromatography and MS, which requires the aerosol to be captured as solid-phase particles and then transformed into a gas or liquid phase. For example, in traditional aerosol sampling methods, particulates are captured on filters, then sealed in a container and sent to a lab that can transform the particulates into a gas or liquid phase. Then the gas or liquid is analysed with mass spectrometry and / or a combination of gas chromatography and mass spectrometry. Transferring the particulates to a lab, however, takes hours if not days; and then receiving the results from the lab can also take hours, if not days. In addition, transferring the particulates to a lab introduces the potential for error by losing or misplacing the particulates to be analysed, or by associating a container of particulates with the wrong person who captured them.[6] Thus, there is a need for a system that can effectively collect and then analyze, in real time or near-real time, particulates included in an aerosol that range in size from greater than 2.5 m to less than 0.1 pm.

[0013] SUMMARY

[0014] [7] In one aspect of the invention, a system for capturing and analyzing particles in an aerosol, the particles having a size within the range of 0.01 pm to 10 pm, includes a collector, a pump, an analyzer, and a release component. The collector is operable to trap a plurality of particles suspended in a fluid, the particles having a size ranging from 0.01 pm to 10 pm. The pump is operable to move the fluid containing the plurality of particles through the collector. The analyzer is releasably coupled with the collector and is operable to analyze material of the trapped particles. The release component is operable to release material of the trapped particles from the collector. The system also includes a conduit that releasably couples the collector with the analyzer and directs material of the particles released from the collector toward the analyzer. The collector may include a microwell collector having a trap that is less than three inches in size and operable to collect a sufficient number of particles in a coarse and / or fine aerosol flowing through the microwell collector at a rate of 0.1 to 10.0 liters per minute (LPM). Alternatively, or additionally, the collector may include a microchannel collector having a trap that is also less than three inches in size and operable to collect a sufficient number of particles that may include biological matter in a coarse and / or fine aerosol flowing through the microchannel collector at a rate of 0.1 to 10.0 LPM. Alternatively, or additionally, the collector may include an electrostatic precipitator (ESP) collector having a trap that is also less than three inches in size and operable to collect a sufficient number of charged particles in an ultrafine aerosol flowing through the ESP collector at a rate of 0.1 to 10.0 LPM. The ESP collector may also include a component that charges particles suspended in the fluid, such as a dielectric-barrier-discharge (DBD) component or a corona ionization component.[8] By combining the analyzer with the collector in the system, and configuring the collector to be easily carried by a single person, the system may be used in the field to identify, within a few minutes, if not in real-time, particles included in coarse, fine, and ultrafine aerosol. The system may identify the particles suspended in any fluid, such as air, carbon dioxide, and nitrogen. With this capability, the system may be used by firefighters combating a fire to identify hazardous products of combustion and / or hazardous biological matter suspended in the air by an inferno. The system may also be used by military personnel during operations to identify deadly particulates before the personnel’s exposure to the particulates kills or maims them. The system may also be used by anyone in the vicinity of a natural disaster, such as a volcanic eruption, and / or an epidemic of an airborne virus. When combined with miniaturized sensors or sensor arrays, the system can also be used for personal monitoring in scientific studies, as well as for occupational and environmental monitoring.

[0015] [9] In another aspect of the invention, a method for capturing and analyzing particles in an aerosol, the particles having a size within the range of 0.01 pm to 10 pm, includes: a) moving a fluid into a collector, the fluid having a plurality of particles suspended within the fluid, the plurality of particles having a size ranging from 0.01 pm to 10 pm; b) then, capturing the plurality of particles in a trap of the collector; c) then, releasing material of the plurality of particles from the collector's trap; d) then, moving the released material of the plurality of particles into an analyzer that is releasably coupled with the collector; and e) then, analyzing the material of the plurality of particles in the analyzer to determine their identity, their concentration, or both.

[0016]

[0010] In another aspect of the invention, a microwell collector for capturing particles in an aerosol, the particles having a size within the range of 0.1 pm to 10 pm, includes a nozzle and a trap. The nozzle is operable to direct toward a location within the collector an aerosol that includes a plurality of particles that range in size from 0.1 pm to 10 pm. The trap has a body that includes a concave surface having a vertex. The trap is positioned in the collector to receive the aerosol from the nozzle and deflect the aerosol toward an axis of the trap’s body that passes through the vertex of the concave surface.With this collector, the system can efficiently capture aerosol over the extended size range and retain particles in the small collection volume,

[0017]

[0011] In yet another aspect of the invention, a method for capturing particles in an aerosol, the particles having a size within the range of 0,1 pm to 10 pm, includes: a) a nozzle directing toward a location within a collector, an aerosol that includes a plurality of particles suspended in a fluid, the particles ranging in size from 0.1 pm to 10 pm; b) then, receiving, with a concave surface of a body of a trap of the collector, the aerosol from the nozzle, the trap being positioned at the location, the concave surface having a vertex; c) then, deflecting the received aerosol toward an axis of the trap’s body that passes through the concave surface’s vertex; d) then, trapping some of the particles of the aerosol in the trap; and e) then, allowing the fluid of the aerosol to leave the trap.

[0018]

[0012] In another aspect of the invention, a collector for capturing particles in an aerosol, the particles having a size within the range of 0.01 pm to 10 pm in size, includes a trap having a channel. The channel has a surface and is configured to contain a flow of fluid in which a plurality of particles that range in size from 0.01 pm to 10 pm are suspended, and turn the flow of the fluid about an axis for an angular distance. The surface of the channel is located about the axis and directs the flow of fluid about the axis, such that when the fluid flows through the channel many of the particles in the flow migrate toward and settle upon the surface.

[0019]

[0013] In yet another aspect of the invention, a method for capturing particles in an aerosol, the particles having a size within the range of 0,1 pm to 10 pm, includes: a) a surface of a trap’s channel directing about an axis for an angular distance, a flow of fluid in which a plurality of particles that range in size from 0.1 pm to 10 pm are suspended, such that as the fluid and the suspended particles flow about the axis the momentum of the particles causes many of the particles to migrate toward and settle upon the surface of the trap's channel; and b) allowing the flow of fluid to escape the trap while the particles remain in the trap.

[0020]

[0014] In another aspect of the invention, a collector for capturing particles in an aerosol, the particles having a size within the range of 0.01 pm to 10 pm in size,includes a trap having an electrostatic-precipitator (ESP). The trap is configured to contain a flow of a fluid in which a plurality of charged particles that range in size from 0.01 pm to 10 pm are suspended. The ESP has a first electrode located in a first region ofthe trap, and a second electrode located in a second region ofthe trap. The first region is exposed to the flow of the fluid in which the plurality of charged particles is suspended, and the first electrode in the first region attracts and captures charged particles suspended in the flow of the fluid. The trap may also include a

[0021] dielectric-barrier-discharge component that has a third electrode, a fourth electrode, and a dielectric barrier disposed between the third and fourth electrode. The third electrode, fourth electrode, and dielectric barrier, together, define an ionization zone that, when the fluid flows through the ionization zone and an electric voltage is applied across the third and fourth electrodes, particles in the fluid become charged.

[0022]

[0015] In yet another aspect of the invention, a method for capturing an aerosol having particles that range in size from 0.01 pm to 10 pm, includes: a) directing a flow of fluid in which a plurality of charged particles that range in size from 0.01 pm to 10 pm are suspended, across a first region of a trap; b) capturing, with a first electrode of an electrostatic-precipitator ofthe trap, the charged particles; c) allowing the flow of fluid to escape the trap while the charged particles remain in the trap. The method may also include charging the particles in the flow of fluid in an ionization zone of a

[0023] dielectric-barrier-discharge (DBD) component ofthe trap before directing the flow of fluid and particles across the first region ofthe trap.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025]

[0016] FIG. 1 shows a schematic view of a system for capturing particles in an aerosol and analyzing material of the captured particles, according to an embodiment ofthe invention.

[0026]

[0017] FlG. 2 shows a perspective view of a portion ofthe system shown in FIG. 1, according to an embodiment of the invention that includes a microwell collector.

[0018] FIG. 3 shows another schematic view of the system shown in FIG. 1, according to an embodiment of the invention.

[0027]

[0019] FIG. 4 shows two different views of a microwell collector, each according to an embodiment of the invention. One of the views is a perspective view, and the other view is a cross-sectional view.

[0028]

[0020] FIG. 5 shows three different views of a trap of the microwell collector shown in FIG. 4, each according to an embodiment of the invention. One of the views is a perspective view; one of the views is a plan view, and one of the views is a

[0029] cross-sectional view.

[0030]

[0021] FIG. 6 shows two different views of a nozzle of the microwell collector shown in FIG. 4, each according to an embodiment ofthe invention. One ofthe views is a perspective view; and the other view is a cross-sectional view.

[0031]

[0022] FIG. 7 shows a perspective view of a portion ofthe system shown in FIG. 1, according to an embodiment of the invention that includes a microchannel collector.

[0032]

[0023] FIG. 8 shows a perspective view of the microchannel collector shown in FIG. 7, according to an embodiment of the invention.

[0033]

[0024] FIG. 9 Shows a perspective, Cross-sectional view of the microchannel collector shown in FIGS. 7 and 8, according to an embodiment ofthe invention.

[0034]

[0025] FIG. 10 shows a perspective view of another microchannel collector, according to an embodiment ofthe invention.

[0035]

[0026] FIG. 11 shows a cross-sectional view of an electrostatic collector of a trap, according to yet another embodiment ofthe invention.

[0036]

[0027] FIG. 12 shows a schematic view of the electrostatic collector shown in FIG. 11, according to an embodiment of the invention.DETAILED DESCRIPTION

[0037]

[0028] FIG. 1 shows a schematic view of a system 30 for capturing and analyzing particles in an aerosol, according to an embodiment of the invention. FIG. 2 shows a perspective view of a portion of the system 30, according to an embodiment of the invention. The system 30 includes a collector 32 that traps a plurality of particles suspended in a fluid (here air), and a pump 34 (FIG. 2) that moves the aerosol through the collector 32. The size of the particles that the collector 32 may trap may range from 0.01 m to 10 pm and may include chemical, biological (viruses, vegetative cells, spores), or aerosolized toxins. The system 30 also includes an analyzer 36 that is releasably coupled with the collector 32 that analyzes material of the particles that were trapped in the collector 32, and a release component 38 that releases materia l of the trapped particles from the collector 32 so that it may be conveyed to the analyzer 36. Material of the trapped particles may include one or more constituents of the trapped particles, and / or a chemical signature of the trapped particles, as well as the particles themselves. The system 30 also includes a conduit 40 (FIG. 2) that releasably couples the collector 32 with the analyzer 36 and directs particles released from the collector 32 toward the analyzer 36.

[0038]

[0029] In operation, the system 30 determines the identity of the material of a particle and / or the concentration of the material, in an aerosol by first drawing, with the pump 34, the aerosol into the collector 32 via an inlet 42 (FIG. 2). The aerosol then flows through the collector 32. As the aerosol flows through the collector 32, coarse, fine and / or ultrafine particles suspended in the fluid of the aerosol are captured and prevented from leaving the collector 32 with the fluid that leaves the collector 32. After a period, aerosol is no longer drawn into the collector 32. With the flow of aerosol stopped, the release component 38 frees material of the captured particles from the collector 32. With the material freed from the collector 32, the pump 34 then urges a carrier fluid through the collector 32 that carries the freed material out of the collector 32 and toward the analyzer 36. The analyzer 36 then analyzes the material received from the collector 32.

[0030] The release component 38 may include any desired release component capable of freeing material of the particles trapped in the collector 32. For example, the release component 38 may include a desorb component (discussed in greater detail in conjunction with FIG.4) that heats the material of the trapped particles and changes the material’s state from solid to liquid or vapor so that the analyzer 36 may effectively determine their identity. When a specific material constituent of the particle is desired, the release component may heat the particle to a temperature at which the desired material will disassociate from the particle and change from a solid to a liquid or vapor. This is especially important when the analyzer 36 includes a system that uses a detector capable of identifying the material’s composition. These can include mass spectroscopy (MS), ion mobility spectroscopy (IMS), and time-of-flight mass spectroscopy (TOF-MS). For another example, the release component 38 may include an elution component (discussed in greater detail in conjunction with FIG.4) that dissolves or suspends the trapped particles in a liquid that is then urged toward the analyzer 36 for identification This is effective for particles of biological matter, such as DNA and viruses. In such situations, additional conditioning may be required to release DNA and / or RNA from these particles. The carrier fluid may be any desired fluid that may carry the liquid or vapor phase of the particles toward the analyzer 36 without adversely affecting the analyzer's ability to determine the identity of the particles. For example, the carrier fluid may be a noble gas, such as helium, when the captured particles are to be converted into the vapor phase for the analyzer 36. In other embodiments, the carrier fluid may be a solvent when the captured particles are to be dissolved in a fluid for the analyzer 36.

[0039]

[0031] The collector 32 may include a microwell collector (discussed in greater detail in conjunction with FIGS. 4 - 6) that has a trap that is less than three inches in size and operable to collect a sufficient number of coarse and / or fine particles in an aerosol flowing through the microwell collector at a rate of 0.1 to 10.0 LPM. Alternatively, or additionally, the collector 32 may include a microchannel collector (discussed in greater detail in conjunction with FIGS. 7 - 10) having a trap that is also less than three inches in size and operable to collect a sufficient number of coarse and / or fine particles that may include biological matter in an aerosol flowing through the microchannel collector ata rate of 0.1 to 10.0 LPM. Alternatively, or additionally, the collector 32 may include an electrostatic precipitator (ESP) collector (discussed in greater detail in conjunction with FIGS. 11 and 12) having a trap that is also less than three inches in size and operable to collect a sufficient number of ultrafine particles in an aerosol flowing through the ESP collector at a rate of 0.1 to 10.0 LPM. In yet other embodiments of the system 30, the collector 32 may include any combination of the microwell, microchannel, and ESP collectors.

[0040]

[0032] By combining the analyzer 36 with the collector 32 in the system 30, configuring the collector 32 to be easily carried by a single person, and releasably coupling the collector 32 with the analyzer 36, the system 30 may be easily carried and used in the field to identify within a few minutes, if not in real-time, coarse, fine, and ultrafine particles in an aerosol. Furthermore, the system 30 may be used to identify a multitude of different particles suspended in air or any other fluid, such as a cloud of methane or carbon dioxide, by coupling a specific collector 32 designed to collect a specific size or type of particle in an aerosol with an analyzer 36 designed to identify the specific particles or class of particles. Then, when the aerosol changes, a different specific collector 32 may be coupled with the same or a different analyzer 36. With this capability, the system 30 may be used by firefighters combating a fire to identify hazardous products of combustion and / or hazardous biological and / or chemical matter suspended in the air by the fire. The system 30 may also be used by military personnel during covert and overt operations to identify deadly particles before exposure to the particles kills or maims them. The system 30 may also be used by anyone in the vicinity of a natural disaster, such as a volcanic eruption, and / or an epidemic ofan airborne virus.

[0041]

[0033] The analyzer 36 may be any desired analyzer capable of determining the identity of a particulate that the collector 32 has extracted from the aerosol. For example, in this and other embodiments of the system 30, the analyzer 36 includes a system for analyzing extracted particles using gas chromatography and mass spectrometry, that is portable. More specifically, in this and other embodiments the analyzer 36 includes a Griffin G510x manufactured by Teledyne FLIR LLC. The Griffin G510x is 15.75 incheslong, 13.25 inches wide, 13.25 inches high, and weighs 38.6 pounds. In other embodiments, the analyzer 36 may include a system for analyzing extracted particles using mass spectrometry alone, that is portable. More specifically, in such other embodiments the analyzer 36 may include an MX908 manufactured by 908 Devices Inc., which is smaller and lighter than the Griffin G510x, or a Clarion manufactured by Detect-Ion Inc. In still other embodiments, the analyzer 36 may include an XplorIR handheld gas detector also manufactured by 908 Devices Inc. In still other embodiments, the analyzer may be an optical sensor, an electronic sensor, and / or a chemical sensor. For biological matter, material of the particles may not be converted to vapor. Instead, the material may be suspended in a liquid and subsequently developed into an assay via polymerase chain reaction (PCR) and / or loop-mediated isothermal amplification (LAMP) that is then analyzed.

[0042]

[0034] Other embodiments of the analyzer 36 are possible. For example, the analyzer 36 may include Time-of-Flight mass spectrometry (TOF-MS), ion mobility spectrometers (IMS). In another example, the analyzer 36 may include a miniature sensor, such as a Metal Oxide Sensor, Field-Effect Transistor (FET), or Organic Framework Field-Effect Transistor (MO F-FET), to reduce the size of the system 30. MOF-FETs are a sensitive, selective chemical sensor where metal-organic frameworks are integrated as functional materials to detect volatile organic compounds (VOCs), neurotransmitters, or drugs. They function by utilizing the porous and chemically tailorable nature of MOFs to adsorb, concentrate, and selectively interact with specific materials, translating these interactions into electrical signals in a transistor platform.

[0043]

[0035] The conduit 40 may be any desired conduit capable of directing the carrier fluid from the collector 32 to the analyzer 36 without contaminating the material of the collected particles in the vapor and / or liquid phase. For example, in this and other embodiments the conduit 40 includes a flexible plastic material. The conduit may also be heated to keep the released particles in the vapor phase. In other embodiments, the analyzer 36 may be coupled directly with the collector 32, releasably or not, and the system 30 may not include a conduit disposed between the collector 32 and the analyzer 36.

[0036] Referring to FIG. 2, in this and other embodiments, the system 30 also includes a first valve 44, a second valve 46, and a controller 48, The first valve 44, when closed, prevents aerosol from flowing through the conduit 40 and into the analyzer 36 when the pump 34 draws the aerosol into and through the collector 32. When open, the first valve 44 allows the carrier fluid to flow through the collector 32 and toward the analyzer 36, The second valve 46 is a three-way valve that controls the flow of both the aerosol and the carrier fluid through the collector 32. When the valve 46 is in a first position, the valve 46 allows the pump 34 to draw aerosol into the collector 32 through the inlet 42. When the valve 46 is in this first position, the valve 44 is closed. When the second valve 46 is in a second position, the valve 46 allows a carrier fluid to flow through the collector 32 and toward the valve 44, which is now open to allow the carrier fluid to flow through the conduit 40. When the second valve 46 is in the second position, the pump 34 is prevented from drawing aerosol into the collector 32, and the inlet 42 is blocked to prevent the carrier fluid from escaping through the inlet 42. In this situation, a second pump (not shown) urges the carrier fluid through the collector 32 and through the conduit 40 to the analyzer 36. When the second valve 46 is in a third position, the valve 46 prevents both carrier fluid and aerosol from flowing through the collector 32. The controller 48 includes circuitry to control the pump 34 and valves 44 and 46. The control may be according to a time schedule, and / or in response to an experienced event, such as encountering a specific particle or exceeding a threshold of a particle’s concentration, and / or in response to entering a specific location.

[0044]

[0037] FIG. 3 shows another schematic view of the system 30 shown in FIG. 1, according to an embodiment of the invention. As mentioned above, the collector component 32 of the system 30 may include any combination of the microwell, microchannel, and ESP collectors. For example, in this and other embodiments the collector 32 may include all three of the microwell, microchannel, and ESP collectors with the microwell and microchannel collectors arranged in parallel with each other relative to the flow of an aerosol through the system 30, and the ESP collector arranged in series with both the microwell and microchannel collectors relative to the flow of aerosol through the system 30. In this system 30, aerosol may flow through both the microwell and microchannel collectors and then flow through the ESP collector. Themicrowell collector may capture Coarse and / or fine particles that may be converted into a vapor before being analyzed by the analyzer 36, while the microchannel collector may capture coarse and / or fine particles that may be dissolved and / or suspended in a liquid before being analyzed by the analyzer 36. Then, the ESP collector may capture ultrafine particles in the aerosol. In these types of embodiments, the analyzer 36 may include a single analyzer 36 that analyses the collected particles from each of the collectors at different moments in time. Or, the analyzer 36 may include two different analyzers, one dedicated to the microwell and microchannel collectors and the other dedicated to the ESP collector. In other embodiments of this system 30, the system 30 may include a trigger that determines whether the aerosol about to flow through the collectors includes biological matter. If the trigger determines that the aerosol does, then the trigger may operate a valve that diverts all or a portion of the aerosol through the microchannel collector. If the trigger determines that the aerosol does not include biological matter, then the trigger may operate a valve that diverts all or a portion of the aerosol through the microwell collector.

[0045]

[0038] Other embodiments of the system 30 are possible. For example, the collector 32 may include a microwell collector or a microchannel collector in series or parallel with an ESP collector. In still other embodiments, the system 30 may include a microchannel collector and a microwell collector that are releasably couplable with an ESP collector so that the system can be easily used in a variety of different situations. For example, when biological particles are expected to be encountered, one can couple the microchannel collector with the ESP collector and then use the system 30 to determine the presence, identity and / or concentration of the particles’ biological material in an aerosol. Then, when biological particles are not expected to be encountered, one may uncouple the microchannel collector and releasably couple a microwell collector to determine the presence, identity, and / or concentration of the particles’ material.Microwell

[0046]

[0039] FIG. 4 shows two different views of a microwell collector 60, each according to an embodiment of the invention. One of the views is a perspective view, and the other view is a cross-sectional view. FIG. 5 shows three different views of a trap 62 of the microwell collector 60 shown in FIG. 4, each according to an embodiment of the invention. One of the views is a perspective view; one of the views is a plan view, and one of the views is a cross-sectional view. FIG. 6 shows two different views of a nozzle 64 of the microwell collector 60 shown in FIG. 4, each according to an embodiment of the invention. One of the views is a perspective view; and the other view is a

[0047] cross-sectional view.

[0048]

[0040] In this and other embodiments, the microwell collector 60 includes the trap 62, the nozzle 64, and a release component having a desorb component 66. The trap 62 captures and holds coarse and fine particles in an aerosol (not shown) as the aerosol flows through the collector 60. The nozzle 64 directs the aerosol entering the collector 60 toward the trap 62. And the desorb component 66 releases material of the captured particles from the trap 62 by heating the trapped particles to convert material of the particles from a solid state to a liquid or a gas state. When converted to the gaseous state, a carrier gas may flow through the collector 60 to convey the material of the particles to the analyzer 36. The collector 60 also includes an inlet 68 through which the aerosol enters the nozzle 64, and an escape 70 through which the aerosol leaves the trap 62 without some, if not most, of the particles that were in the aerosol when the aerosol entered the trap 62, The collector 60 also includes a main tube 72 having a first portion 74, and a second portion 76. When the collector 60 captures coarse and fine particles in an aerosol flowing through the collector 60, the aerosol flows through the first portion 74 of the main tube 72 in the direction of the arrow 78. When the release component releases material of the captured particles, by changing it into its gaseous state, a carrier gas (not shown) flows through the main tube 72 in the direction of the arrow 80 to carry the gaseous material toward the analyzer 36 (FIG. 1).

[0049]

[0041] In operation, aerosol enters the collector 60 through the inlet 68; flows through the nozzle 64; and impacts the trap 62. The aerosol, without some of its particles, thenflows through the escape 70 that surrounds the outside of the nozzle 64, and back toward the inlet 68. When the aerosol enters the main tube 72, the aerosol then proceeds through the first half 74 of the tube 72; drawn by the pump 34 (FIG. 2). After the aerosol flows through the pump 34, the aerosol flows out of the system 30 (FIG. 2) and into the environment. When the release component releases material of the captured particles, a carrier gas enters the first half 74 of the main tube 72 through the portal 82 and flows through the first half 72, then the second half 74 of the tube 72, and out the portal 84 toward the conduit 40 (FIG. 2).

[0050]

[0042] The microwell collector 60 captures coarse and fine particles in an aerosol by generating a flow of aerosol with the nozzle 64 and then directing the flow to the trap 62 that abruptly changes the direction of the flow. This abrupt change in the flow's direction makes it difficult for the particles in the aerosol to track the movement of the fluid — i.e., remain suspended in the fluid — as the aerosol flows through the trap 62. Consequently, some, if not most, of the particles remain in the trap 62 while the fluid of the aerosol flows out of the trap 62. Because the trap 62 works by taking advantage of the difference between the mass and structure of the fluid and particles, and the change in the flow's direction caused by the trap 62, the combination of the speed of the aerosol's flow entering the trap and the configuration of the trap 62 allows the trap to capture particles in the aerosol. The difference between the fluid and a particle in the flow of aerosol may be quantified as the Stokes number of the particle in the flow. The Stokes number is a dimensionless number that describes the behavior of a particle in a fluid flow, and more particularly, the particle's tendency to follow the fluid's motion versus its own inertia. A Stokes number of 1 means that the particle's behavior in the flow is significantly influenced by both the particle’s inertial force and the fluid’s viscous drag. In this realm, the more abrupt the change in the flow’s direction becomes, the more difficult it becomes for a particle to track the flow. A Stoke’s number that is much greater than 1 means that a particle's behavior in the flow is dominated by the particle's inertial force, and the fluid’s viscous drag has little influence. In this realm, a gradual change in the flow’s direction may still make it difficult for a particle to track the flow. A Stoke's number that is much less than 1 means that a particle’s behavior in the flow is dominated by the fluid's viscous drag on the particle, and the particle's inertial force haslittle influence. In this realm, an abrupt change in the flow’s direction may not be difficult for a particle to track the flow. To ensure that the flow of aerosol through the microwell collector 60 does not experience abrupt changes in the flow's direction before the flow reaches the trap 62, the flow should remain laminar — i.e., smooth and orderly, without turbulence — through the nozzle 64. More specifically, the Reynolds number of the flow should be less than 10,000, or even better, less than 2300. So, for the microwell collector 60 a Stokes number of 10 with a Reynolds number less than 2300 allows the trap 62 to capture coarse and fine particles in air.

[0051]

[0043] Referring to FIG. 5, the trap 62 may be configured as desired to generate an abrupt change in the direction of flow that flows through it. For example, in this and other embodiments the trap 62 includes a body 90 that has a concave surface 92, and an axis 94 that passes through the vertex 96 of the concave surface 92. More specifically, the concave surface 92 is configured as a truncated cone that has an angle of 55 degrees, and area of the vertex 96 that is 0.3215 square millimeters. The angle of the cone is a measure of the slope of the cone’s surface, and the area of the vertex 96 is the area of the surface that connects the sloped surface of the cone. The trap 62 is oriented relative to the nozzle 64 so that the flow of aerosol from the nozzle 64 flows along the axis 94 and enters the trap 62 through the opening 98. The flow then contacts the concave surface 92 and is deflected toward the axis 94. This causes the aerosol in the trap 62 to mix, making it difficult for the particles of the aerosol to track with the flow of the aerosol's fluid. As more aerosol enters the trap 62 through the opening 98, the aerosol already in the trap is urged out of the trap 62 back through the opening 98. As the aerosol mixes, particles crash into the concave surface, bounce around inside the trap 62, and settle into eddies generated inside the trap 62 by the mixing of the aerosol. To help keep captured particles inside the trap 62, the body 90 may also include a lip 100 that extends from the perimeter of the concave surface 92 toward the axis 94. The lip 100 does this by deflecting particles and fluid of the aerosol back toward the axis 94 before they can escape, and by allowing eddies to form between the lip 100 and the concave surface 92.

[0044] Other embodiments are possible. For example, the trap 62 may include a sacrificial layer, such as a sugar, disposed on the concave surface 92 and / or the underside of the lip 100 to help capture and hold particles that impact the layer, and that may be dissolved to release the captured particles. The trap 62 may also be configured to trap particles in an aerosol whose fluid is more or less dense than air and whose particles are larger or smaller than the coarse and fine particles captured by the trap 62 discussed above. For example, the concave surface 92 may be configured as a truncated cone that has an angle of more or less than 55 degrees, and may include an area of its vertex that is more or less than 0.3215 square millimeters. As another example, the concave surface may be configured to have an angle that varies as the surface extends away from the vertex 94, and the lip 100 may extend from the perimeter more or less than 0.5 millimeters, and at an angle that is greater than 90 or less than 90 degrees relative to the axis 94. As yet another example, the concave surface 92 may have a surface roughness or a film on the concave surface 92 that helps hold particles to the surface.

[0052]

[0045] Referring to FIG. 6, The nozzle 64 may be configured as desired to generate a flow of aerosol, and direct the flow to the trap 62. For example, in this and other embodiments the nozzle 64 is configured to aerodynamically focus the flow of aerosol by narrowing the flow and concentrating the particles within the flow, without increasing the flow rate of the aerosol through the microwell collector 60. Aerodynamic focusing of the particles is often used to achieve a collimated particle beam, particularly for increasing particle concentration. Such focusing devices may include a series of orifices that decrease in size through which the aerosol flows. For laminar flow conditions, as the aerosol flows through the series of orifices, the flow forces particles greater than a specific Stokes number into a narrow beam along the centerline. More specifically, the nozzle 64 directs 1.0 to 5.0 LPM toward the trap 62 and includes an exit 106 and a duct 108 that extends from the inlet 68 (FIG.4) to the exit 106. The duct 108 has a cross-sectional diameter that narrows as the duct extends from the inlet 68 to the exit 106. At the inlet 68 the cross-sectional diameter of the duct is 2.04 mm and remains this dimension for 24.0 mm. Then, the cross-sectional diameter reduces to 1.0mm and remains this dimension for 5.0 mm. Then the cross-sectional diameter reduces to 0.51mm and remains this dimension to the exit 106.

[0053]

[0046] Other embodiments are possible. For example, the nozzle may be sized and configured to convey less than 1 LPM or more than 5 LPM. As another example, the nozzle may not be configured to aerodynamically focus the aerosol, and may be configured to increase or decrease the flow rate of the aerosol through the microwell collector 60.

[0054]

[0047] The desorb component 66 may be configured as desired to release material of the particles captured in the trap 62. For example, in this and other embodiments the desorb component 66 includes a heater (110 in FIG. 4) located next to the trap's body 90 on the opposite side of the concave surface 92 that heats the body 90 and thus the particles captured in the trap 62. More specifically, the heater 110 includes a ceramic heater that generates heat by resisting the flow of electricity through its heating element and is capable of rapidly heating the trap 62 to a temperature of 300 degrees Celsius (°C) in about 20 seconds. To help enable the heater to quickly warm the trap 62, the trap 62 may be made of brass or any other material having a low thermal inertia. The other components of the microwell collector 60 may also be made of brass or any other material having a low thermal inertia that can also help ensure that the volume of the trap 62, escape (70 in FIG. 4), and main tube (72 in FIG.4) remain free of condensation. In addition, with each of the components made of brass, the trap 62 and other components of the microwell 60 may quickly shed their heat after the desorb component is turned off and aerosol starts flowing through the collector 60. The desorb component 66 also includes a thermistor to sense the temperature of the trap 62 and allow the controller (48 in FIG. 2) to modify the amount of heat generated by the heater (110 in FIG.4) in response to a specific, desired protocol. In this and other embodiments, the desorb component 66 may heat the trap 62 to specific temperatures that increase over time and hold each specific temperature for a desired duration. In this manner, the desorb component 66 may desorb a variety of different material of the particles captured from an aerosol that have a variety of different boiling points.

[0048] Referring back to FIG. 2, the controller 48 may be configured as desired to: 1) allow one to control the process for capturing particles in an aerosol, and 2) allow one to control the process for releasing material of the captured particles from the trap 62 and convey the material of the particles to the analyzer (36 in FIG. 1). For example, in this and other embodiments the controller 48 controls the flow of aerosol through the trap 62 by controlling power to the pump 34, and operating the second valve (46 in FIG. 2) so that aerosol may flow through the valve 46 and to the pump 34. The control may be based on time in which the controller 48 powers the pump for a specific, desired duration, like 1 or 5 minutes. Then, the controller 48 may prevent power from reaching the pump 34 to stop the pump 34, and may operate the second valve 46 so that the pump 34 is isolated from the trap 62. The controller 48 may also operate the first valve (44 in FIG. 2) so that a carrier gas and gaseous material of the trapped particles may flow to the analyzer 36. Then, the controller 48 may instruct the desorb component 66 to commence operating. Then, when the desorb component 66 is finished, the controller 48 may power the pump 34 to draw aerosol back through the microwell 60 for another cycle of capturing particles in the aerosol. In this and other embodiments, the controller 48 includes a Proportional-Integral-Derivative (PID) controller to control the desorb component 66. The control here may be based on the desired temperature of the trap 62 and its duration compared with the actual temperature of the trap and its duration as experienced by the thermistor. More specifically, the desired temperature and duration may include a series of different temperatures each for a specific duration. When the first temperature and duration cycle has finished, the PID controller can instruct a second pump to operate to move the material of the trapped particles that entered the gaseous state during the cycle toward the analyzer (36 of FIG. 1). In this and other embodiments the second pump urges an inert gas, such as N2or a noble gas to flow through the main tube 72 to convey the gaseous material with minimal adverse effects. After the second pump has been operating for a specific, desired period, the PID controller stops the second pump and starts to power the heater (110 of FIG.4) to heat the trap 62 to the desired temperature for the desired duration of this subsequent cycle. This allows the system 30 to isolate and analyze different materials of the particles captured by the trap 62 such as highly volatile material that becomes gas at a first temperature (e.g. 100°C), followed by a less volatile material that becomes gas at asecond temperature (e.g. 200°C), followed by an eVen less volatile material that becomes gas at a third temperature (e g. 300°C).

[0055] MicroChannel

[0056]

[0049] Each of FIGS. 7 - 10 shows a view of a microchannel collector 150, according to an embodiment of the invention. FIG. 7 shows a portion of the system 30 that includes the microchannel collector 150, according to an embodiment of the invention. Each of FIGS. 8 and 9 shows a view of the microchannel 150; and FIG. 10 shows a view of a different microchannel collector, according to another embodiment of the invention. As previously mentioned, the microchannel collector 150 may be used alone in the system 30, or the microchannel collector 150 may be used in conjunction with either the microwell collector (FIGS. 2 - 6), the ESP collector (FIGS. 11 and 12), or both. The microchannel collector 150 may be used to collect particles in an aerosol in which the particles have a size within the range of 0.1 pm to 10 pm, and is especially useful for collecting particles that are best conveyed to the analyzer 36 (FIG. 1) via a carrier liquid, such as biological matter like DNA, RNA, enzymes, and biotoxins, that could be altered or destroyed if desorbed from the collector 150 by being heated to a gaseous state like the material of trapped particles released from the microwell collector (60 in FIG.4).

[0057]

[0050] In this and other embodiments, the microchannel collector 150 includes a trap 152 (see FIG. 9), and a release component (38 in FIGS. 1 and 3) having an elution component 154. The trap 62 captures and holds particles in an aerosol (not shown) as the aerosol flows through the collector 150. The elution component 154 releases material of the captured particles from the trap 150 by washing the trap 152 with a solvent that can remove the particles from the surface of the trap 152 (discussed in greater detail in conjunction with FIG. 9). When the particles are suspended in the solvent, the solvent may then flow out of the trap 152 and toward the analyzer (36 in FIGS. 1 and 3) for analysis. The collector 150 also includes an inlet 155 through which the aerosol enters, and an escape 156 through which the aerosol leaves the trap 152 without some, if not most, of the particles that were in the aerosol when the aerosolentered the trap 152. The collector 150 may also include a nozzle (not shown in FIGS.

[0058] 7 - 10) that is similar to the nozzle 64 that is discussed in conjunction with the microwell collector in FIGS. 4 and 6, to aerodynamically focus the flow of aerosol through the collector 150 by narrowing the flow and concentrating the particles within the flow, without increasing the flow rate of the aerosol through the microchannel collector 150.

[0059]

[0051] In operation, the pump 158 draws aerosol into the system 30 through the port 160. The aerosol then flows through the tube 162, through the inlet 155, and then into the trap 152. As the aerosol flows through the trap 152, the flow impacts a surface of the trap 152 (here three, which are discussed in greater detail in conjunction with FIG.

[0060] 9) that turns the flow and causes some, if not most, of the particles in the flow to settle out onto the surface. The aerosol then continues to flow through the trap 152 without some of its particles and eventually flows out of the trap 152 through the escape 156. The aerosol then flows through the tube 164 toward the pump 158. After the aerosol flows through the pump 158, the aerosol flows out of the system 30 and into the environment. When the release component releases material of the captured particles from the trap 152, a solvent enters the trap 152 through the portal 166, flows through the trap 152, and then exits the trap 152 through the portal 168.

[0061]

[0052] The microchannel collector 150 captures particles in an aerosol in a manner similar to how the microwell 60 captures particles in an aerosol, i.e., by generating a flow of aerosol and then directing the flow through the trap 152 that abruptly changes the direction of the flow. This abrupt change in the flow’s direction makes it difficult for the particles in the aerosol to track the movement of the fluid, which causes the particles to deposit or settle out onto a surface of the trap 152. Thus, the same considerations of the mass and structure of the aerosol's fluid and particles, and the change in the flow’s direction caused by the trap 152, influence the configuration of the trap 152. More specifically, and as previously discussed in conjunction with the microwell collector 60, the Stokes number of the particle in the flow of the aerosol, and the Reynolds number of the aerosol’s flow, influence the configuration of the trap 152.

[0062]

[0053] Referring to FIG. 9, the trap 152 may be configured as desired to generate an abrupt change in the direction of flow that flows through it. For example, in this andother embodiments the trap 152 includes a channel 170 that has a Surface 172 where particles suspended in the aerosol settle out of the of aerosol while the aerosol flows through the channel 170. The channel 170 is configured to contain the flow of the aerosol through the trap 152 while the channel 170 turns the flow of aerosol about an axis 174 for an angular distance. More specifically, the channel 170 turns the flow of aerosol three times, each time around a different axis 174. In other embodiments, the channel 170 may be configured to turn the flow of aerosol one, two, or four or more times around one or more common axes 174, or around a respective one of the axes 174. The channel 170 has a cross-sectional area of about 1 mm2, a cross-sectional shape that is rectangular, and extends through the microchannel collector for about 20 mm. Each of the three surfaces 172 extends about its respective axis 174 for an angular distance of about 180 degrees, and remains the same distance away from its respective axis 174 as it extends about it. More specifically, each of the surfaces 172 is located 2.5 mm away from its respective one of the axes 174. In other words, each of the surfaces 172 is essentially a cylinder having a diameter of 5 mm and that has been cut in half along the cylinder’s longitudinal axis which is colinear with the axis 174. In this configuration, the channel 172 turns the flow of aerosol sharp enough to cause particles suspended in the flow that are between 0,1 pm to 10 pm to not be able to track the flow and consequently collect on the surfaces 172.

[0063]

[0054] Other embodiments are possible. The trap 62 may be configured to trap particles in an aerosol whose fluid is more or less dense than air and whose particles are larger or smaller than 0.1 pm to 10 pm. For example, each of the surfaces 174 may be located closer to its respective one of the axes 174, and / or may extend about its respective axis for an angular distance that is longer than or shorter than 180 degrees. As another example, one or more of the surfaces 172 may have a surface roughness or a film that helps hold particles to the surface. The film may be a sacrificial layer, such as a sugar, that helps hold particles that settle out of the flow of the aerosol and that is removed from the surface 172 when the solvent dissolves the sacrificial layer and releases the collected particle during elution.

[0055] The elution component 154 may be configured as desired to release material of the particles captured in the trap 152. For example, in this and other embodiments the elution component 154 includes a reservoir 176 and a pump. The reservoir 176 holds the solvent that will wash the trap’s surfaces and release the captured particles, particle components, and / or chemical signatures. The solvent may be any desired solvent capable of dissolving or releasing the specific particles from the trap 152. For analysis of organic matter, the particle or its organic constituents can be dissolved into organic solvent, such as alcohols, acetonitrile, and acetone. When the biological integrity and viability of an organism need to be preserved, the collected particle may be eluted with water, surfactant, or a buffer solution for culture analysis. When DNA of a biological organism needs to remain intact but the viability of the organism does not need to be preserved, then a lysing agent may be used as an eluant. If a sacrificial layer, such as a sugar like sucrose, or treulose are used in the trap, then a polar solvent such as water (with or without a surfactant such as tween 20) may be used to dissolve the sacrificial layer. The pump moves the solvent into the channel 170 of the trap 152, and then, after the surfaces 172 have been washed, the pump moves the solvent and the particles out of the trap 152 and toward the analyzer 36 (FIGS. 1 and 3). More specifically, in this and other embodiments, the reservoir 176 and the pump combine to form a syringe with the plunger of the syringe moveable within the barrel of the syringe to control the flow of the solvent through the trap 152, and the tip of the syringe releasably coupled with the microchannel collector's portal 166. To help the solvent wash the trap’s surfaces 172, the solvent may be agitated when in the trap’s channel. This agitation may be done by physically vibrating the microchannel collector 150, or the agitation may be done by the pump cyclically increasing and decreasing the pressure of the solvent so that the solvent is moved back and forth across the surfaces 172.

[0064]

[0056] Other embodiments are possible. For example, the elution component 154 may also include a heater similar to the heater (110 in FIG. 4) of the desorption component (66 in FIG. 4) that may warm the solvent and / or particles captured in the trap 152 to promote the dissolution of the particles. As another example, the elution component's pump may be a peristaltic pump that when stopped prevents the solvent from leaving the reservoir 176, or the elution component’s pump may be a piezoelectric pump.

[0057] Referring back to FIG. 7, the system 30 also includes a first valve (not shown) that also controls the flow of the elution component’s solvent through the microchannel collector 150 and toward the analyzer, and a second valve 180 that controls the flow of aerosol through the microchannel collector 150. The first valve may be any desired valve capable of performing this function. For example, in this and other embodiments the first valve is a pinch valve that when open allows solvent to flow toward the trap 152, and when closed prevents solvent from flowing in either direction. The first valve also isolates the elution component 154 from the microchannel collector 150 when the aerosol flows through the collector 150. Similarly, the second valve 180 may be any desired valve capable of preventing aerosol from flowing toward the trap 152 when closed, and thus isolating the microchannel collector 150 from the environment when the elution component 154 washes the collector's trap 152. For example, in this and other embodiments the second valve 180 includes two ball valves. One of the ball valves controls the flow of aerosol through the tube 162 toward the microchannel collector 150, and the other ball valve controls the flow of aerosol through the tube 164 toward the pump 158.

[0065]

[0058] Still referring to FIG. 7, the system 30 also includes a controller 182 that is similar to the controller 48 (FIG. 2) and that may be configured as desired to: 1) allow one to control the process for capturing particles in an aerosol, and 2) allow one to control the process for releasing material of the captured particles from the trap 152 and conveying the material to the analyzer (36 in FIGS. 1 and 3). For example, in this and other embodiments the controller 182 controls the flow of aerosol through the trap 152 by controlling power to the pump 158, and operating the second valve 180 so that aerosol may flow through the valve 180 and to the pump 158. The control may be based on time in which the controller 182 powers the pump 158 for a specific, desired duration, like 1 or 5 minutes. Then, the controller 182 may prevent power from reaching the pump 158 to stop the pump 158, and may operate the second valve 180 so that the pump 158 is isolated from the trap 152, The controller 182 may also operate the first valve so that elution component’s solvent and dissolved released particles flow to the analyzer 36. Then, the controller 182 may instruct the elution component 154 to commence operating. Then, when the elution component 154 is finished, the controller182 may power the pump 158 to draw aerosol back through the microchannel collector 150 for another cycle of capturing particles in the aerosol. In this and other embodiments, the controller 182 includes a PID controller to control the elution component 154. The control here may also be based on time. More specifically, washing the trap’s surfaces 172 may occur for a period between 30 and 60 seconds. When the elution cycle has finished, the PID controller can instruct the elution component’s pump to operate to move the solvent and particles toward the analyzer 36. In this and other embodiments the elution component’s pump urges the solvent to flow through the trap’s channel 170 to convey the eluted particles, particle components, and / or chemical signatures with minimal adverse effects. After the elution component’s pump has been operating for another specific, desired period, to move the solvent with the particles toward the analyzer, the PID controller stops the pump, closes the first valve, opens the second valve 180, and allows power back to the pump 158 to urge more aerosol to flow through the microchannel collector 150.

[0066]

[0059] FIG. 10 shows a perspective view of another microchannel collector 190, according to an embodiment of the invention. The microchannel collector 190 is similar to the microchannel collector 150, except that the microchannel collector 190 is rectangular, and the channel 170 has a more complex shape and is oriented so that the solvent from the elution component 154 is held in the channel 170 below the inlet 155 and escape 156 to reduce cross-contamination during agitation of the solvent in the channel 170.

[0067] Electrostatic Precipitator (ESP) and Dielectric Barrier Discharge (DBD)

[0068]

[0060] Each of FIGS. 11 and 12 shows a view of an electrostatic collector 200, each according to another embodiment of the invention. FIG. 11 shows a cross-sectional view of the electrostatic collector 200, and FIG. 12 shows a schematic view of the collector 200. The electrostatic collector 200 may be used to collect charged particles 201 (only five labeled in FIG. 12 for clarity) in an aerosol in which the particles 201 have a size within the range of 0.01 pm to 10 pm, such as aerosolized toxins and combustionbyproducts, and, as previously mentioned, may be used alone in the system 30 (FIGS.

[0069] 1 and 3), or in conjunction with either the microwell collector 32 (FIGS. 2 - 6), the microchannel collector 150 (FIGS. 7 - 10), or both. The electrostatic collector 200 may be plugged into or coupled with the system 30 in a manner similar to the coupling of the microwell collector 32 as shown in FIG. 2, or the microchannel collector 150 as shown in FIG. 7. Also, controlling the flow of aerosol through the collector 200 and the flow of captured particles out of the collector 200 and toward the analyzer 36 (FIGS. 1 and 3) by the system 30 may be similar to the system’s control of these flows through and out of the microwell collector 32 and the microchannel collector 150. The collector 200 includes a release component 202 to release material of the captured particles 201, from the collector and allow material of the particles 201 to be conveyed to an analyzer 36 for analysis. The collector 200 may also charge desired particles 201 in an aerosol before capturing the particles 201.

[0070]

[0061] In this and other embodiments, the electrostatic collector 200 includes a trap 202, and a release component 204. The trap 202 captures and holds particles 201 in an aerosol (not shown) as the aerosol flows through the collector 200. The release component 204 releases material of the captured particles 201 from the trap 202 by heating the material of the captured particles 201 to change the material's state from solid to liquid or vapor (discussed in greater detail in conjunction with FIG. 12). When the particles are in the liquid or vapor state, the liquid and / or vapor may then flow out of the trap 202 and toward the analyzer 36 (FIGS. 1 and 3) for analysis. In other embodiments, the release component 204 may release the material of captured particles 201 without heating them. In such embodiments, the release component 204 may release the particle's 201 by reducing the electrostatic force within the trap 202 that holds the particles 201 in the trap 202. The collector 200 also includes an inlet 206 through which the aerosol enters, and an escape 208 through which the aerosol leaves the trap 202 without some, if not most, of the particles 201 that were in the aerosol when the aerosol entered the trap 202. The collector 200 may also include a nozzle (not shown in FIGS. 11 and 12) that is similar to the nozzle 64 that is discussed in conjunction with the microwell collector 32 (FIGS. 4 and 6), to aerodynamically focus the flow of aerosol through the electrostatic collector 200 by narrowing the flow andconcentrating the particles 201 within the flow, without increasing the flow rate of the aerosol through the collector 200.

[0071]

[0062] In operation, aerosol is urged into the inlet 155 by a pump (not shown in FIG 12, but similar to the pump 34 in FIG.2) of the system 30 (FIGS. 1 and 3), flows through the inlet 206, through the trap 202, and then through the outlet 208 (shown as arrows 210). As the aerosol flows through the trap 202, the aerosol flows through a collection zone 212 that includes an electrostatic field. As the aerosol flows through the electrostatic field, charged particles 201 in the aerosol are attracted to a region of the trap 202 inside the collection zone by the force that the electrostatic field exerts on the charged particle 201, and are held there by the same force. The aerosol then continues to flow through the trap 202 without some of its particles 201 and eventually flows out of the trap 202 through the outlet 208. After the aerosol leaves the trap 202, the aerosol flows out of the system 30 and into the environment. To release the material of the captured particles 201 from the region within the collection zone 212, the flow of aerosol through the inlet 206 is stopped, and the strength of the electrostatic field may be reduced, removed or even reversed to mitigate the electric field’s hold on the charged particles 201. Then, the region may or may not be heated to desorb the material of captured particles 201 from the region. To move the released material of the particles toward the analyzer 36 (FIGS. 1 and 3), a carrier fluid flows through the inlet 206, the collection zone 212 of the trap 202, and then through the exit 214.

[0072]

[0063] Because the collector 200 uses electrostatic force to capture particles 201 in a flow of aerosol, the force generated by the electrostatic field on the charge of each of the particles 201 should be sufficient to overcome the inertial and viscous forces experienced by the particles 201 as the aerosol flows through the collection zone 212. The strength of the electrostatic field’s force on the particle 201 is monotonically proportional to the strength of the electrostatic field at the location Within the field where the particle 201 lies, and the amount of charge that the particle 201 has. The strength of the electrostatic field is, in turn, directly proportional to the voltage between the electrodes in the collection zone 212, and inversely proportional to the distance away from the electrodes in the zone 212. So, a positively charged particle 201 that lies adistance away from the negatively charged electrode will experience less force form the electrostatic field than a similar particle 201 that lies closer to the negatively charged electrode. As previously discussed, the inertial and viscous forces that the particle 201 experiences in the flow of aerosol can be expressed as a ratio of the two — it’s Stoke number. The balance between each of the coulombic, viscous, and inertial forces acting on the charged particle influences the configuration and operation of the trap 202.

[0073]

[0064] Still referring to FIGS. 10 and 11, the trap 202 may be configured as desired. For example, in this and other embodiments the trap 202 includes the collection zone 212, and an ionization zone 214 (discussed in greater detail in conjunction with FIG. 12) that charges particles 201 in the aerosol before the aerosol flows through the collection zone 212. Although this and other embodiments of the trap 202 include an ionization zone 214, still other embodiments of the trap 202, do not. In such embodiments, the trap 202 may just include the collection zone 212 that captures particles 201 in the aerosol that already have a charge when they enter the trap 202 through the inlet 206. Back to the trap 202 shown in FIGS. 11 and 12, the trap 202 includes a tube 216 that has a longitudinal axis 218, and a cylinder 220 positioned inside the tube 216 colinear with the tube’s longitudinal axis 218, such that the collection zone 212 of the trap 202 is an annular ring in cross-section. The trap 202 also includes an electrostatic precipitator (ESP) 222 located in the collection zone 212, that attracts and captures charged particles 201. The ESP 222 includes a first electrode 224 positioned in a first region 226 of the trap 202, and a second electrode 228 positioned in a second region 230 of the trap 202. To generate the electrostatic field in the collection zone 212, a voltage is applied across the first and second electrodes 224 and 228, respectively. In this and other embodiments, a DC voltage is applied with the second electrode 228 being ground, and the first electrode 224 biased negatively. In this configuration, positively charged particles 201 will be attracted to and held at the first region 226 of the trap 202, and negatively charged particles 201 will be attracted to and held at the second region 230, The ESP 222 also includes control circuitry to modify the voltage applied across the first and second electrodes 224 and 228, respectively. In other embodiments, the first electrode 224 or the second electrode 228 may be located in their respective one ofregions 226 and 230 so that only particles 201 having either a positive charge or a negative charge are captured by the ESP 222.

[0074]

[0065] Other embodiments are possible. The trap 202 may be configured to trap particles in an aerosol whose fluid is more or less dense than air and whose particles are larger or smaller than 0.01 pm to 10 pm. For example, the trap 202 may be configured such that the collection zone 212, in cross-section, is not an annular ring, but rather a circle. In such embodiments both the first and the second electrodes 224 and 228, respectively, may be positioned in the wall of the tube 216 diametrically opposite each other, or not. In yet another example, collection zone 212 of the trap 202 may be rectangular with the first and second electrodes 224 and 228, respectively positioned on opposite side of the zone 212.

[0075]

[0066] Still referring to FIGS. 10 and 11, the release component 204 may be configured as desired. For example, in this and other embodiments the release component 204 is similar to the release component discussed in conjunction with the microwell collector 32 (FIGS. 2 - 6). More specifically, the release component 204 includes a heater that heats the material of the captured particles 201 to change the material’s state from solid to vapor and then directs the vapor to the analyzer 36 (FIGS. 1 and 3). Here, the heater includes the first electrode 224 that is made of an electrically resistive material that generates heat when electric current flows through the material. In these embodiments, the first electrode 224 is included in two circuits that may be electrically isolated from the other. The first circuit applies a direct current across the first and second electrode 224 and 228, respectively, to generate the electrostatic field in the collection zone 212, The second circuit applies an electric current through the first electrode 224.

[0076] Additionally, or alternatively, the heater of the release component 204 may include the second electrode 228. The release component 204 also includes a carrier fluid, as previously discussed with the microwell and the microchannel collectors, that may carry the liquid or vapor phase of the material of the particles 201 toward the analyzer 36 without adversely affecting the analyzer’s ability to analyze the material. Also as previously discussed with the microwell and microchannel collectors, the releasecomponent 204 may also include control circuitry and a thermistor to modify the amount of heat generated by the heater in response to a specific, desired protocol.

[0077]

[0067] Other embodiments are possible. For example, the release component 204 may also include control circuitry that modifies the electrostatic field generated in the collection zone 212. The control circuitry may reduce the strength of the electrostatic field, it may temporarily remove the electrostatic field from the connection zone 212, and / or it may reverse the electrostatic field, all of which to mitigate the electric field’s hold on the charged particles 201. For another example, the portion of the cylinder 220 where the first electrode 224 is located may include a ceramic material generates heat when an electric current flows through it. In such embodiments, the first electrode 224 may or may not be used by the release component 204 to generate heat in the collection zone 212.

[0078]

[0068] The electrostatic collector 200 may also charge particles 201 in an aerosol that one would like to capture to help the ESP 222 of the trap 202 capture the desired particles 201. For example, in this and other embodiments the trap 202 includes a dielectric-barrier-discharge (DBD) component 232 that generates a cloud of ions in the ionization zone 214 when powered. When the aerosol flows through the cloud of ions some of the ions attach themselves to some of the particles 201 in the aerosol. Once charged, the electrostatic field of the ESP 222 can then capture and hold the charged particles 201 until the release compone nt 204 releases material of the particles 201. The DBD component 232 includes a third electrode 234, a fourth electrode 236, and a dielectric barrier 238, each of which is located in the ionization zone 214. More specifically, each of the electrodes 234 and 236, and the barrier 238 is positioned in the wall of the tube 216 and displaced relative to each other along the longitudinal axis 218 of the tube 216. In this and other embodiments, the wall of the tube 216 includes a dielectric, ceramic material so the area of tube’s wall separating the third and fourth electrodes 234 and 236 can function as the dielectric barrier 238. In other embodiments, the dielectric barrier 238 may be a different material, such as Kapton, Teflon, quartz, and silicon, than the tube’s wall. To generate DBD micro-discharges in the ionization zone 214, an AC or pulsed DC voltage is applied across the third andfourth electrodes 234 and 236, respectively. In other embodiments, the third electrode 234 or the fourth electrode 236 may be located in the cylinder 220 opposite the other electrode. When the release component 204 is engaged to release material of the captured particles 201, the voltage across the third and fourth electrodes may be stopped so that the DBD component does not generate micro-discharges in the ionization zone 214.

[0079]

[0069] The preceding discussion is presented to enable a person skilled in the art to make and use the invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

What is claimed is:System1. A system for capturing particles in an aerosol and analyzing material of the particles, the particles having a size within the range of 0.01 pm to 10 pm, the system comprising:a collector operable to trap a plurality of particles suspended in a fluid, the particles having a size ranging from 0.01 pm to 10 pm;a pump operable to move the fluid containing the plurality of particles through the collector;an analyzer releasably coupled with the collector and operable to analyze material of the trapped particles; anda release component operable to release material of the trapped particles from the collector,2. The system of claim 1 wherein the collector includes a micro-well component,3. The system of claim 1 wherein the collector includes a micro-channel component.

4. The system of claim 1 wherein the collector includes an electrostatic-precipitator component.

5. The system of claim 1 wherein the collector includes at least two of the following components: a micro-well component, a micro-channel component, and an electrostatic component.6 The system of claim 1 wherein the collector includes at least two of the following components: a micro-well component, a micro-channel component, and an electrostatic component, arranged parallel with each other relative to the analyzer.

7. The system of claim 1 wherein the collector includes at least two of the following components: a micro-well component, a micro-channel component, and an electrostatic component, arranged in series with each other relative to the analyzer.

8. The system of claim 1 wherein the material of the trapped particles includes one or more of the following: a constituent of the trapped particle, and a chemical signature of the trapped particle.

9. The system of claim 1 wherein the analyzer includes a mass spectrometer.

10. The system of claim 1 wherein the release component includes a desorb component having a heater operable to heat the trapped particles and convert volatile compounds to vapor phase.

11. The system of claim 1 wherein the release component includes an elution component operable to release the trapped particles out of the collector.

12. The system of claim 1 further comprising a conduit that releasably couples the collector with the analyzer and directs particles released from the collector toward the analyzer.

13. The system of claim 12 wherein the conduit is releasably coupled with both the collector and the analyzer.

14. A method for capturing particles in an aerosol and analyzing material of the particles, the particles having a size within the range of 0.01 pm to 10 pm, the method comprising:moving a fluid into a collector, the fluid having a plurality of particles suspended within the fluid, the plurality of particles having a size ranging from 0.01 pm to 10 pm;capturing the plurality of particles in a trap of the collector;releasing material of the plurality of particles from the collector’s trap;moving the released material of the plurality of particles into an analyzer that is releasably coupled with the collector; andanalyzing the released material of the plurality of particles in the analyzer to determine at least one of its identity and concentration.

15. The method of claim 14, wherein capturing the plurality of particles in the trap of the collector includes colliding the plurality of particles against a wall of the collector's trap.

16. The method of claim 15, wherein colliding the plurality of particles against a wall of the collector’s trap includes colliding the plurality of particles against the wall of a micro-well component.

17. The method of claim 15, wherein colliding the plurality of particles against a wall of the collector’s trap includes colliding the plurality of particles against the wall of a micro-channel component.

18. The method of claim 14, wherein capturing the plurality of particles in the trap of the collector includes:applying an electric charge to each of the plurality of particles, and holding the charged plurality of particles to a surface of the collector's trap that has an electric charge that is opposite the electric charge of the plurality of particles.

19. The method of claim 14, wherein capturing the plurality of particles in the trap of the collector includes:capturing some of the plurality of particles in a first collector’s trap, and capturing other of the plurality of particles in a second collector's trap, wherein the second collector’s trap is parallel with the first collector’s trap relative to the analyzer.

20. The method of claim 14, wherein capturing the plurality of particles in the trap of the collector includes:capturing some of the plurality of particles in a first collector’s trap, and capturing other of the plurality of particles in a second collector's trap, wherein the second collector's trap is in series with the first collector's trap relative to the analyzer.

21. The method of claim 14, wherein releasing the plurality of particles from the collector’s trap includes heating the plurality of particles.

22. The method of claim 14, wherein releasing the plurality of particles from the collector’s trap includes washing the plurality of particles out of the collector’s trap.

23. The method of claim 14, wherein analyzing the plurality of particles includes determining the ratio of ions of the particle’s mass to its charge via mass spectrometry.

24. The method of claim 14, further comprising uncoupling the collector from the analyzer, and coupling a second collector with the analyzer wherein the second collector is different than the first collector.Micro well Collector25. A collector for capturing particles in an aerosol, the particles having a size within the range of 0.1 micrometers (pm) to 10 pm, the collector comprising:a nozzle operable to direct toward a location within the collector an aerosol that includes a plurality of particles that range in size from 0.1 micrometers (pm) to 10 pm; anda trap having a body that includes a concave surface having a vertex, the trap positioned in the collector to receive the aerosol from the nozzle and deflect the aerosol toward an axis of the body that passes through the vertex of the concave surface.

26. The collector of claim 25, wherein the body’s surface is operable to hold a particle previously included in the aerosol.

27. The collector of claim 25, wherein the concave surface includes a truncated cone.

28. The collector of claim 27, wherein the truncated cone has an angle of 55 degrees.

29. The collector of claim 27, wherein the concave surface’s vertex has an area of 0.312 square (mm²).

30. The collector of claim 27, wherein the body includes a lip that extends from a perimeter of the concave surface toward the body’s axis and deflects the aerosol moving away from the concave surface's vertex back toward the body’s axis.

31. The collector of claim 30, wherein the lip extends toward the body’s axis at a 90-degree angle relative to the axis.

32. The collector of claim 30, wherein the lip extends toward the axis for a length that is between 0.05 and 0.85 times the distance between the axis and the perimeter of the concave surface.

33. The collector of claim 30, wherein the lip extends toward the axis for a length of 0.5 (mm).

34. The collector of claim 33, wherein the nozzle directs the aerosol flowing at (0.1 to 10 Standard Liters Per Minute (SLPM) or at 32 F and 100kPa).

35. The collector of claim 25, wherein the nozzle aerodynamically focuses the aerosol to narrow and concentrate the flow of the aerosol before the aerosol is projected towards the trap’s concave surface.

36. The collector of claim 25, further comprising a release component operable to release material of the particles removed from the aerosol and held in the trap.

37. The collector of claim 36, wherein the release component includes a heater operable to heat the material of the particles held in the trap to desorb the material.

38. The collector of claim 36, wherein the trap's body is a metal to reduce thermal inertia of the body.

39. The collector of claim 37, wherein the heater generates heat by resisting the flow of electricity through a heating element.

40. The collector of claim 37, wherein the release component includes control circuitry to control the amount of heat generated by the heater overtime.

41. The collector of claim 36, wherein the release component includes a pump operable to move the material of released particles toward an analyzer operable to analyze the material.

42. The collector of claim 41. wherein the pump moves an inert gas through the trap to carry the material of released particles into the analyzer.

43. A method for capturing particles in an aerosol, the particles having a size within the range of 0.1 micrometers (pm) to 10 pm, the method comprising:directing, with a nozzle, toward a location within a collector, an aerosol that includes a plurality of particles suspended in a fluid, the particles ranging in size from 0.1 micrometers (pm) to 10 pm;receiving, with a concave surface of a body of a trap of the collector, the aerosol from the nozzle, the trap being positioned at the location, the concave surface having a vertex;deflecting the received aerosol toward an axis of the trap’s body that passes through the concave surface's vertex;trapping some of the particles of the aerosol in the trap; andallowing the bulk fluid to leave the trap.

44. The method of claim 43, wherein directing the aerosol with the nozzle includes aerodynamically focusing the aerosol to narrow and concentrate the flow of the aerosol before the concave surface receives the aerosol.

45. The method of claim 43, wherein deflecting the received aerosol includes deflecting the aerosol with a lip that extends from a perimeter of the concave surface toward the axis.

46. The method of claim 43, wherein trapping the particles includes some of the particles settling out of the aerosol while the fluid of the aerosol flows through the trap.

47. The method of claim 43, further comprising a release component heating the body’s surface to desorb the particles from the trap's body.

48. The method of claim 47, further comprising controlling, with control circuitry, the amount of heat generated by the release component overtime.

49. The method of claim 47, further comprising moving the desorbed particles from the trap’s body toward an analyzer.MicroChannel Collector50. A collector for capturing particles in an aerosol, the particles having a size within the range of 0.01 micrometers (pm) to 10 pm in size, the collector comprising: a trap having a channel configured to:contain a flow of fluid in which a plurality of particles that range in size from 0.01 micrometers (pm) to 10 pm are suspended, and turn the flow of the fluid about an axis for an angular distance; the channel having a surface located about the axis that directs the flow of fluid about the axis, such that when the fluid flows through the channelmany of the particles in the flow migrate toward and settle upon the surface.

51. The collector of claim 50, wherein the channel’s surface includes a component for holding particles that contact the surface.

52. The collector of claim 50, wherein the channel’s surface is a section of a toroid.

53. The collector of claim 50, wherein the angular distance around the axis is 180 degrees.

54. The collector of claim 50, wherein the channel:is configured to turn the flow of the fluid about a first axis for a first angular distance and about a second axis for a second angular distance, and includes:a first surface located about the first axis that directs the flow of fluid about the first axis, such that when the fluid flows through the channel many of the particles in the flow migrate toward and settle upon the first surface, anda second surface located about the second axis that directs the flow of fluid about the second axis, such that when the fluid flows through the channel many of the particles in the flow migrate toward and settle upon the second surface.

55. The collector of claim 50, further comprising an elution component mounted to the trap and operable to wash the trapped particles out ofthe channel.

56. The collector of claim 55, wherein the elution component includes a pump operable to inject a solvent into the channel, and to repeatedly move the solvent in opposite directions within the channel.

57. The collector of claim 56, wherein the pump is operable to move the eluted particles toward an analyzer operable to analyze the particles.

58. A method for capturing particles in an aerosol, the particles having a size within the range of 0,1 micrometers (pm) to 10 pm, the method comprising:a surface of a trap’s channel directing about an axis for an angular distance, a flow of fluid in which a plurality of particles that range in size from 0.1 micrometers (pm) to 10 pm are suspended, such as the fluid and the suspended particles flow about the axis the momentum of the particles causes many of the particles to migrate toward and settle upon the surface of the trap’s channel; andallowing the flow of fluid to escape the trap while the particles remain in the trap.

59. The method of claim 58, further comprising holding particles that have migrated to the surface with a component of the channel's surface.

60. The method of claim 58, wherein directing the flow of fluid with a surface about an axis includes:a first surface directing the flow of fluid about a first axis, anda second surface directing the flow of fluid about a second axis.

61. The method of claim 58, further comprising washing the particles off of the channel’s surface with an elution component.

62. The method of claim 61, wherein washing the particles off of the channel's surface includes injecting a solvent into the channel, and repeatedly moving the solvent in opposite directions within the channel.

63. The method of claim 61, further comprising moving the eluted particles from the surface of the trap’s channel toward an analyzer.Electrostatic Collector64. A collector for capturing an aerosol having particles that are 0.01 micrometers (pm) to 10 pm in size, the collector comprising:a trap having an electrostatic-precipitator and configured to contain a flow of fluid in which a plurality of charged particles that range in size from 0.01 micrometers (pm) to 10 pm are suspended, the electrostatic-precipitator having:a first electrode located in a first region of the trap,a second electrode located in a second region of the trap, wherein the first region is exposed to the flow of the fluid in which the plurality of charged particles is suspended, and wherein the first electrode In the first region attracts and captures charged particles suspended in the flow of the fluid.

65. The collector of claim 64, wherein a direct current is applied across the first and second electrodes to generate an electric charge in each of the electrodes.

66. The collector of claim 64, wherein the first electrode has a negative charge and attracts and captures positively charged particles.

67. The collector of claim 64, wherein:the trap includes:a tube having a longitudinal axis,a cylinder having a longitudinal axis and located in the tube such that the tube’s longitudinal axis and the cylinder’s longitudinal axis are colinear, andas the fluid flows through the tube, the cylinder is submerged in the fluid.

68. The collector of claim 67, wherein the first electrode is located inside the cylinder, and the second electrode is located inside the tube.

69. The collector of claim 67, wherein the first electrode is located inside the cylinder, and the second electrode is located inside the tube directly opposite the first electrode.

70. The collector of claim 64, further comprising a release component operable to release material of the charged particles captured by theelectrostatic-precipitator.

71. The collector of claim 70, wherein the release component includes a heater operable to heat the material of the charged particles captured by the electrostatic-precipitator.

72. The collector of claim 71, wherein the release component applies a current through the electrostatic-precipitator’s first electrode to heat the trap’s first region.

73. The collector of claim 71, wherein the release component applies a current through the first region such that the first region generates heat.

74. The collector of claim 71, wherein the release component includes control circuitry to control the amount of heat generated over time.

75. The collector of claim 70, wherein the release component includes a pump operable to move released material of charged particles toward an analyzer operable to analyze the particles.

76. The collector of claim 75, wherein the pump moves an inert gas through the trap to carry the released material of charged particles into the analyzer.

77. The collector of claim 64, wherein the trap includes a dielectric-barrier-discharge component having a third electrode, a fourth electrode, and a dielectric barrier disposed between the third and fourth electrode, wherein the third electrode, fourth electrode, and dielectric barrier, together, define an ionization zone that, when the fluid flows through the ionization zone and an electric voltage is applied across the third and fourth electrodes, particles in the fluid become charged.

78. The collector of claim 77, wherein an alternating voltage is applied across the third and fourth electrodes to create dielectric barrier discharge.

79. The collector of claim 77, wherein:the trap includes:a tube having a longitudinal axis,a cylinder having a longitudinal axis and located in the tube such that the tube’s longitudinal axis and the cylinder’s longitudinal axis are colinear, andas the fluid flows through the tube, the cylinder is submerged in the fluid; the third electrode is located inside the tube; andthe fourth electrode is located inside the tube a distance away from the third electrode along the tube’s longitudinal axis.

80. A method for capturing an aerosol having particles that range in size from 0.01 micrometers (pm) to 10 pm, the method comprising:directing a flow of fluid in which a plurality of charged particles that range in size from 0.01 micrometers (pm) to 10 pm are suspended, across a first region of a trap;capturing, with a first electrode of an electrostatic-precipitator of the trap, the charged particles;allowing the flow of fluid to escape the trap while the charged particles remain in the trap.

81. The method of claim 80, wherein capturing the charged particles includes applying a voltage across the first electrode and a second electrode of the electrostatic-precipitator to generate a charge on the first electrode that attracts the charged particles.

82. The method of claim 80, further comprising releasing material of the captured particles from the electrostatic-precipitator.

83. The method of claim 80, wherein releasing material of the captured particles from the electrostatic-precipitator includes desorbing the material of captured particles from the first electrode by heating the captured particles.

84. The method of claim 83, wherein desorbing the material of captured particles includes applying a current through the first electrode to generate heat.

85. The method of claim 83, wherein desorbing the material of captured particles includes controlling, with control circuitry, the amount of heat generated over time.

86. The method of claim 82, wherein releasing material of the captured particles includes moving the released particles toward an analyzer operable to analyze the material.

87. The method of claim 86, wherein moving the material of released particles includes pumping an inert gas through the trap’s electrostatic-precipitator.

88. The method of claim 80, further comprising charging particles in the flow of fluid in an ionization zone of a dielectric-barrier-discharge component of the trap before directing the flow of fluid and particles across the first region of the trap.

89. The method of claim 88, wherein charging the particles in the ionization zone includes applying an alternating voltage across a third electrode and a fourth electrode, wherein a dielectric barrier is disposed between the third and fourth electrodes.

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