Aerosols from natural, anthropogenic and industrial sources have long been recognized as a potential threat to human health; to that list of sources we now must add airborne chemical or biological warfare agents as a source of potentially lethal exposure or terrorist threat. Effective sampling and collection of aerosol particles is a critical first step in the detection and identification of these hazards. Identification methods such as immunological or nucleic acid assays typically require the aerosol sample to be suspended in a liquid medium. There is therefore a need for a “front-end” device adapted to collect these aerosols and prepare or deliver them in a concentrated suspension or solution for analysis.

Higher concentration of aerosol particles in a liquid sample achieves greater sensitivity for many analyses. Today’s micro analytical instruments require microliter or nanoliter sample volumes, and larger volumes of liquid are difficult to process. Moreover, currently available aerosol collectors cannot readily be adapted to perform sample preprocessing prior to analysis, a significant disadvantage for integrated sampling and detection platforms. Sample preprocessing includes processes such as dissolution of sample matrix, lysis of suspect cellular contents, or preliminary screening to trigger more exhaustive analysis, process steps which speed threat detection and avoid unnecessary analyses.

An apparatus or device for collecting aerosol particles from a gas stream, having a collector body enclosing a collector channel, a particle trap in the collector channel, and an injection duct for injecting a discrete microdroplet of an elution reagent. The particle trap may be a centrifugal impactor, a bluff body impactor, or an electrostatic impactor. Aerosol particles are deposited on the surface during collection and are subsequently eluted with a microdroplet or a series of microdroplets as a concentrated liquid sample so that the sample can be analyzed in situ or conveyed to a detector for analysis. The collector serves as an aerosol-to-liquid conversion module as part of an apparatus for detecting and analyzing aerosol particles, and may be used in an integrated environmental threat assessment system, for example for characterization of aerosolized chemical and biological weapons, or for industrial or environmental monitoring.

Devices and methods for sampling and analysis of airborne particles (aerosols) from a moving airstream find use in environmental and industrial sciences and for surveillance. The most informative aerosol particles for the purposes contemplated here are those less than 20 microns in apparent aerodynamic diameter (AD), and particularly those particles of about or less than 10 microns AD, because these particles remain suspended in air for longer periods of time and more readily penetrate and lodge in the respiratory tract.

Aerosol sampling is made more difficult by wind, mist, dust and rain, and can be complicated when the aerosol sampling device is mounted on a mobile vehicle such as a truck, airplane, marine vessel or riverine vehicle. Design of a sampling inlet can also be problematic because of the accumulation of sand, salt crystals, dust, and fibers, and also water spray. Under heavy loading, particulate solids such as dust and fibers have been known to accrete so as to block the sampling inlet or reduce sampling efficiency and performance. Filter pads sometimes used for trapping aerosols also become blocked or tear when wetted by rain or mist.

An aerosol sampling intake configured to exclude particles generally greater than 20 microns AD and capture particles of less than about 10 microns AD with high efficiency, independent of weather conditions, through which air is sampled by suction. The intake combines an omnidirectional horizontal segment with diffuser and elbow, the elbow transitioning flow to a vertical segment, the vertical segment with overhanging lip, the centrifugal impactor for self-cleaning operation, thus relieving the dual problems of re-entrainment of particles bouncing from the impactor surface and fouling by particles sticking to the impactor surface. The device is adapted for use on moving vehicles, for sampling at increased windspeeds, or for sampling in rain.

Atmospheric aerosols from natural, anthropogenic, and industrial sources have long been recognized as a potential threat to human health. This threat is now compounded by the need to detect and avert acts of terrorism where an infectious or toxic material is deployed in the form of an aerosol. Particles that present the greatest hazard in terms of inhalation and nasal entrapment or lung deposition are respirable particles in the range of 0.02-25 µm diameter.

One major challenge that must be addressed by all aerosol samplers is that many aerosols occur at extremely low concentrations, or may be only a small fraction of the urban background aerosol distribution. The aerosol must thus generally be concentrated before sampling. Convergent nozzles and aerodynamic lenses are effective in focusing an aerosol into a beam of particles, a particle-rich core surrounded by a sheath of particle-depleted gas.

A skimmer device for concentrating an aerosol from a flowing gas stream, having an inlet with inlet aperture and inlet raceway, an outlet with virtual impact void and collector channel, and bulk flow divertors symmetrically disposed on either side of the long axis of flow, further characterized in that the downstream walls of the bulk flow divertors are concavedly curved and reverse the direction of bulk flow. In section, the four channels or passages of the “skimmer” thus form a “crossed tee” with concavedly contoured lateral arms curving back around. The lateral flow channels are for diverting the bulk flow into exhaust chimney spaces, and the chimney spaces are positioned proximate to the inlet element and anterior to the collection channel. In operation, the bulk flow streamlines are thereby folded more than 90 degrees away from the long axis of flow on the laterally disposed concave walls of the bulk flow channels. While counterintuitive, this was found using computational fluid dynamics (CFD) and experimentation to dramatically reduce wall separation and related instabilities and to improve particle recoveries. Large two-dimensional arrays of closely stacked inlet and skimmer elements are thus achieved by fitting the chimneys into spaces between parallel inlet elements. The interlinked problems of flow instability, manufacturability of arrays, and scale-up of chimney cross-sectional area to equalize pressure differentials in the bulk flow diverter exhaust ducts, particularly in two-dimensional arrays at high throughput, are uniquely solved with this geometry.

Atmospheric aerosols from natural, anthropogenic and industrial sources have long been recognized as a potential threat to human health. To that list of sources, chemical or biological warfare (CBW) agents due to acts of terrorism must now be added as a source of potentially lethal contamination. Effective sampling and concentration of CBW agents is a critical first step in the detection of these aerosols, and much effort has gone into developing effective methods for rapid screening and detection of CBW agents in samples which can then be analyzed to assess the risk of exposure to these aerosols.

One major challenge that must be addressed by all aerosol samplers is that most aerosols occur at extremely low concentrations, or may be only a small fraction of the urban background aerosol distribution. Therefore, not only is it necessary to sample large volumes of air in order to collect sufficient material for accurate detection, but for most measurement techniques it is also necessary to concentrate the aerosol and restrict the fraction collected to a range of particle sizes that is of greatest importance for the target agents. This latter step can help focus collection efforts on particles that present the greatest hazard in terms of inhalation or lung deposition (i.e. respirable particles in the range <10 .mu.m diameter), and also helps discriminate nuisance aerosols from the sampling train.

Respirable particles with diameters on the order of 0.05 to 10 microns entrained in an air stream, are concentrated in an aerodynamic lens (FIG. 2) for separation from the air steam. The entire structure is made by microfabrication techniques, such as silicon micro-machining which enables arrays of precisely aligned slit lenses to be made on a silicon chip. At a Reynolds number of 800, a slit 25 microns wide by 1 mm tall will pass a flow of only 0.28 liters per minute, but arrays of lenses (FIG. 4), stacked in parallel banks, multiplies the available flow rate. Placing a skimmer (27) at the exit of each silicon micro-machined lens in the assembly and connecting the skimmer channels in chimneys (55), allows the bulk of the gas flow to be stripped off while allowing the concentrated particle stream to pass into a region of much lower flow rate, thereby producing a highly concentrated aerosol in the low velocity stream.

There is a need for inspection and sampling of persons, articles of clothing, buildings, furnishings, vehicles, baggage, cargo containers, dumpsters, packages, mail, and the like for contaminating residues (termed here more generally “trace analytes” or “target analytes”) that may indicate chemical hazards, explosives hazards, or illicit substances, while not limited thereto. Potential applications involve detection of trace materials, as both particles and vapors, associated with the presence of explosives on articles, on vehicles, or on persons, for example.

In particular, the recent increased threat to society from explosive devices and illicit drug traffic has led to the development of sensitive systems for the detection of vapors and particles from explosives and drugs.

Current methods for surface sampling often involve contacting use of swabs or liquids, but methods for sampling by “sniffing” are preferred, where air in contact with a suspect package or person is drawn into a detection system directly.

Apparatus and methods for selectively separating a volatile constituent of a particle from a gas stream for analysis. Particles are separated from bulk flow by inertia and impacted in a cavity containing a small but stable vortex or eddy. Heat is applied to volatilize constituents of the particles. The gas entrained within the vortex, which exchanges only slowly with the bulk flow, is withdrawn for analysis. In this way, a high volume flow containing particles of interest is reduced to a low volume flow containing a vapor concentrate. Advantageously, the apparatus may be operated at very low pressure drops in fully continuous, semi-continuous or batch mode according to the requirements of the downstream analytical unit. The apparatus finds use in active surveillance, such as in use of aerosols to detect explosives or chemical residues on persons, vehicles or luggage in real time.

There is a need for inspection and sampling of persons, articles of clothing, buildings, furnishings, vehicles, baggage, cargo containers, dumpsters, packages, mail, and the like for contaminating residues (termed here more generally “trace analytes”) that may indicate chemical, radiological, biological, illicit, or infectious hazards. Applications involve detection of trace materials, both particles and optionally vapors, associated with persons who have handled explosives, detection of toxins in mail, or detection of spores on surfaces, while not limited thereto.

Current methods for surface sampling often involve contacting use of swabs or liquids, but methods for sampling by “sniffing” are preferred.

Devices, apparatus and methods are disclosed for non-contact pneumatic sampling and sampling of surfaces, persons, articles of clothing, buildings, furnishings, vehicles, baggage, packages, mail, and the like, for contaminating aerosols indicative of a hazard or a benefit, where the contaminating aerosols are chemical, radiological, biological, toxic, or infectious in character. In a first device, a central orifice for pulling a suction gas stream is surrounded by a peripheral array of convergingly-directed gas jets, forming a virtual sampling chamber. The gas jets are configured to deliver millisecond pneumatic pulses that erode particles from solid surfaces at a distance. In another aspect of the invention, a suction gas stream is split using an air-to-air concentrator so that a particle-enriched gas flow is directed to a particle trap and any particles immobilized in the particle trap (including any adsorbed vapors associated with the particles) are selectively analyzed to detect trace residues associated with explosives.

There is a need for non-invasive inspection and sampling of persons, articles of clothing, buildings, furnishings, vehicles, baggage, packages, mail, and the like for contaminating residues that may indicate chemical, radiological, biological or infectious hazards. Applications involve detection of trace materials, both particles and vapors, associated with persons who have handled explosives, detection of toxins in mail, or detection of spores on surfaces, while not limited thereto.

Current methods for environmental sampling often involve contacting use of swabs or liquids to obtain samples that are indicative of the composition of the environmental material of interest, but methods for sampling by “sniffing” are preferred.

Devices and methods are disclosed for non-contact pneumatic sampling of surfaces, persons, articles of clothing, buildings, furnishings, vehicles, baggage, packages, mail, and the like, for aerosols or vapor residues indicative of a hazard or a benefit, where the residues are chemical, radiological, biological, toxic, or infectious in character. A central orifice for pulling a vacuum is surrounded by an array of convergingly-directed gas jets, forming a “virtual sampling chamber”. The gas jets are configured to deliver millisecond pneumatic pulses that erode particles and vapors from solid surfaces at a distance. A curtain wall flow encloses the sampling area during pulse retrieval.