Abstract: There is provided apparatus for the measurement of particle mass concentration of an aerosol and which comprises at least one aerosol inlet and at least one electrostatic precipitator which directs an aerosol flow towards a mass sensor on which the particles are collected, the sensor being housed in a magazine including a plurality of other sensors, each of which may be substituted for the sensor, and a control. The control selectively connects one of the at least one aerosol inlet with one of the sensors.

Abstract: A method for determining the characteristic properties of soot particles originating from combustion processes utilizes the determination of the blackening of a filter paper. In order to allow for achieving a quick and relatively accurate determination of the particle sizes, possibly of further characteristics as well, a method of this kind provides that the pressure conditions on the filter paper are established as well. It is advantageous for this purpose to determine the differential pressure on the filter and/or filter paper caused by the deposition of the particles.

Abstract: A technique for determining particulate density in a fluid monitors the changes in the speed of sound. Since the speed of sound is intimately related to the composites of the air mixture and since the speed of sound of clean air at any temperature and humidity can be calculated exactly, it is possible to estimate the density of any foreign particulates in the air by observing changes in the speed of sound. Formulations are derived that correlate the change in the speed of sound of the air mixture to their density fluctuations, thus allowing people to estimate the mass density of foreign particulates under any temperature and humidity. Alternatively, the change in density of the air mixture can be detected, thereby indicating the presence of contaminants and a possible alarm, even if the contaminants are not yet identified.

Abstract: A self-contained closed loop system and method for detecting contaminants in, on, and around objects. The system includes an air duct subsystem connecting at least one sensor to a sealed housing containing a rotating container. Air from the sealed housing is circulated past a sensor to detect, for example, biological or chemical contaminants. If a contaminant is detected, an indicator is set and a contaminant neutralizer is optionally injected into the air duct subsystem.

Abstract: A mail tub in the form of a substantially rigid container and a removable lid which seals the container. The container includes an air inlet port and an air outlet port for sampling air in the mail tub for possible biological contamination, such as anthrax. The container includes structure along the bottom and walls to prevent mail from contacting the walls and bottom. Such structure, in one embodiment, may include raised standoffs along the bottom of the container and channels along the walls to facilitate airflow efficiency through the mail tub when the lid is attached and an air pressure source is applied to the one of the ports. Air samples of the sealed container air are collected for contamination analysis.

Abstract: A particulate mass monitor includes a controller that monitors a change in a resonant oscillation frequency of a taut metallic membrane, as caused by deposition of the particulate matter on the metallic membrane. The metallic membrane, such as a foil or metallized plastic film, is substantially mechanically stable under tension. Application of a tension to the periphery of the metallic membrane generates a substantially constant tension within the membrane, thereby allowing the particulate mass monitor to detect a particulate mass concentration of the air sample with a relatively high degree of accuracy. Additionally, the particulate mass monitor includes a membrane transporter that automatically advances the metallic membrane within the particulate mass monitor. The membrane transporter minimizes the necessity for manual replacement of the metallic membrane over time and allowing long term, unattended operation of the particulate mass monitor.

Abstract: Electrical connecting lines of a sensor element are anchored by friction locking, specifically using an annularly closed spring element which clamps the connecting lines against contact surfaces on the sensor element using pressure bodies.

Abstract: The invention disclosed herein relates generally to mailpieces and more particularly, a hazardous material detector for detecting hazardous material in a mail stream. The present invention is directed, in general to detector for collecting sample (s) of hazardous materials from a mail processing device. The mailpiece generally comprises an envelope comprising a front side and a back side; holes formed in at least one of the front side or the back side of the envelope; a hazardous material test strip for detecting the presence of hazardous material in contact with the test strip; whereby when hazardous materials are detected by the hazardous material test strip a physical change occurs to the hazardous material test strip and the physical change can be viewed through at least one hole formed in the at least one of the front side or the back side of the envelope. The detector helps to quickly determine whether hazardous materials are present in the mail stream.

Abstract: Systems and methods for the detection of substances (particularly particulate substances) within mail pieces, specifically letters and other “flats” of mail. In particular, the systems and methods are for the detection of residues of Chemical or Biological Warfare Agents (CBWAs) which may be present within the mail pieces. The system is principally designed to be included as part of Dual Pass Rough Cull System (DPRCS) for the collection and detection of the residue when the contaminated mail piece first enters a mail facility and before it is intermingled with other mail pieces. The system also utilizes aerosol chambers using at least two arrays of pinch rollers to provide for decreased incremental changes on mail pieces and decrease the likelihood of mail piece damage.

Abstract: Systems and methods for the detection of substances (particularly particulate substances) within mail pieces, specifically letters and other “flats” of mail. In particular, the systems and methods are for the detection of residues of Chemical or Biological Warfare Agents (CBWAs) which may be present within the mail pieces. The system is principally designed to be included as part of Dual Pass Rough Cull System (DPRCS) for the collection and detection of the residue when the contaminated mail piece first enters a mail facility and before it is intermingled with other mail pieces. The system also utilizes aerosol chambers using at least two arrays of pinch rollers to provide for decreased incremental changes on mail pieces and decrease the likelihood of mail piece damage.

Abstract: The apparatus described herein is a miniaturized system for particle exposure assessment (MSPEA) for the quantitative measurement and qualitative identification of particulate content in gases. The present invention utilizes a quartz crystal microbalance (QCM) or other mass-sensitive temperature compensated acoustic wave resonator for mass measurement. Detectors and probes and light sources are used in combination for the qualitative determination of particulate matter.

Abstract: A method and apparatus for particle collection (30) that is characterized by co-aerosolizing fluids (62) into an air stream (34) containing the particles to be analyzed to significantly enhance their collection and identification efficiency is provided.

Abstract: An adapter for use with a low volume PUF sampler is described. The adapter is affixed over the open end of a PUF (polyurethane foam) sample cartridge. Sample tubing is affixed to an aperture in the adapter, and the free end of the sample tubing is then positioned at a desired sample location such as within an aircraft interior. As a vacuum is applied to the PUF cartridge, the adapter allows air collected at the sample point to pass through the tubing and through the interior of the PUF cartridge while preventing air surrounding the PUF cartridge from being drawn into the PUF cartridge except through the sample tubing. In this manner the sample point of a desired air sample can be selected at a point remote from the PUF cartridge. Additionally, use of multiple PUF cartridges and adapters allows the simultaneous collection of separate air samples.

Abstract: A device for ascertaining a particle concentration in an exhaust gas flow of a combustion device, particularly a diesel combustion device, is provided, which device ascertains very small particle concentrations in the exhaust gas of combustion devices, accompanied by high time resolution. At least one measuring unit is provided for measuring a concentration of an oxidizing agent in the exhaust gas flow, having at least one measuring element sensitive to the oxidizing agent.

Abstract: Systems and methods for the detection of substances (particularly particulate substances) within mail pieces, specifically letters and other “flats” of mail. In particular, the systems and methods are for the detection of residues of Chemical or Biological Warfare Agents (CBWAs) which may be present within the mail pieces. The system is principally designed to be included as part of Dual Pass Rough Cull System (DPRCS) for the collection and detection of the residue when the contaminated mail piece first enters a mail facility and before it is intermingled with other mail pieces.

Abstract: A particulate mass monitor includes two mass sensors, such as an optical sensor (e.g., a light scattering photometer or nephelometer) and a beta radiation attenuation sensor for substantially continuous monitoring of ambient particulate matter. During operation, the first mass sensor references the time-averaged measurement of the second mass sensor such that the second mass sensor calibrates the response of the first mass sensor. If the first sensor is an optical sensor, as it detects the presence of particulate matter within a fluid, the mass concentration measurement (e.g., signal output) provided by the optical sensor is altered using a ratio of concentration measurements of the second mass sensor and the optical sensor. The combined use of the two mass sensors provides accurate mass measurements of ambient particulate matter with a relatively high time resolution.

Abstract: Systems and methods for the detection of substances (particularly particulate substances) within mail pieces, specifically letters and other “flats” of mail. In particular, the systems and methods are for the detection of residues of Chemical or Biological Warfare Agents (CBWAs) which may be present within the mail pieces. The system is principally designed to be included as part of Dual Pass Rough Cull System (DPRCS) for the collection and detection of the residue when the contaminated mail piece first enters a mail facility and before it is intermingled with other mail pieces. The system also utilizes aerosol chambers using at least two arrays of pinch rollers to provide for decreased incremental changes on mail pieces and decrease the likelihood of mail piece damage.

Abstract: Systems and methods for the detection of substances (particularly particulate substances) within mail pieces, specifically letters and other “flats” of mail. In particular, the systems and methods are for the detection of residues of Chemical or Biological Warfare Agents (CBWAs) which may be present within the mail pieces. The system is principally designed to be included as part of Dual Pass Rough Cull System (DPRCS) for the collection and detection of the residue when the contaminated mail piece first enters a mail facility and before it is intermingled with other mail pieces.

Abstract: Fiber optic particle detector for measurements in a fluid flow, comprising an optical fiber (2,3,12) being acoustically coupled to a mechanical element (11,13,14) adapted to be acoustically coupled to the flow, a fiber optic interferometer (54,56) and a light source (12,51,55) providing light in said optical fiber.

Abstract: A method of measuring concentration of solid or liquid particulate matter in a gaseous carrier medium, particularly suitable for measuring concentration and flow rate of pulverized fuel pneumatically transported in a duct to power station boiler burners. The method includes generating a radio frequency electromagnetic wave within a duct, measuring wave parameters within a range of frequencies, including a cut-off frequency, determining the cut-off frequency from changes in wave parameters, calculating dielectric permittivity of a two-phase flow duct load, and ascribing to this value a corresponding concentration value. The measured parameter is the rate of change of phase shift against frequency at two arbitrary points on a wave transmission path, whereas the waveguide cut-off frequency value is determined at a point where the rate of change of phase shift against frequency reaches a maximum.

Abstract: The application discloses several methods of detecting particles moving in a gas flow, a detection means (70), a method of improving the linearity of the signal produced by a triboelectric particle detector, a method to test a signal path of an emission monitor, an emission monitor for detecting particles, and a method of detecting faults in a triboelectric probe of system for detecting particles entrained in a gas flow. The particle detection means (70) includes a gas flow deflection means (40) having an upstream face (43) and a downstream face (45) and a detector (42, 44) associated exclusively with the downstream face (45). Deflecting the gas flow creates vortices that have little effect on the large particles, but cause the small particles to move close to the detectors on the downstream face. Therefore the downstream detectors (42, 44) are particularly sensitive to light particles. The method improves of small particles and provides accurate particle counts.

Abstract: In a sampling tube-type smoke detector equipped with a smoke detection device detects smoke particles contained in the air suctioned from a monitored area through a sampling tube by an aspirator positioned in the downstream. The smoke detection device the sampling tube forms a lead-in tube and suctions air through the sampling tube in substantially a straight line. The lead-in tube is formed with a smoke sensor unit to detect smoke particles contained in the air. The aspirator comprises a rotating part which forms an actuator mechanism that discharges the air. The central axis of the lead-in tube and the rotational axis of the actuator mechanism of the aspirator are substantially on the same axis. The sampling tube-type smoke detector is provided to reduce pressure loss in the airflow traveling from the smoke detection device to the aspirator and to supply a low cost, compact smoke detection device driven by a small-sized fan.

Abstract: An apparatus for continuous on-line measurement of chemical composition of aerosol particles with a fast time resolution is provided. The apparatus includes an enhanced particle size magnifier for producing activated aerosol particles and an enhanced collection device which collects the activated aerosol particles into a liquid stream for quantitative analysis by analytical means. Methods for on-line measurement of chemical composition of aerosol particles are also provided, the method including exposing aerosol carrying sample air to hot saturated steam thereby forming activated aerosol particles; collecting the activated aerosol particles by a collection device for delivery as a jet stream onto an impaction surface; and flushing off the activated aerosol particles from the impaction surface into a liquid stream for delivery of the collected liquid stream to an analytical instrument for quantitative measurement.

Abstract: An in-situ particle monitor in an exhaust controls a particle sampler so that when a predetermined particle threshold is detected, the particle sampler is caused to gather samples from the exhaust in real-time. Electrical control signals are monitored to correlate variations in the signals with particle excursions for both analysis and sample collection triggering.

Abstract: A dust collection apparatus includes a container and a suction pump that sucks dust and transports it into the container. A filter is provided on a side surface of the container. This filter passes air but prevents passage of the dust in the container. A pressure detector detects an internal pressure of the container. The internal pressure of the container fluctuates due to a variation in an effective area of the filter for allowing the air to pass according to the dust collected and accumulated in the container. A dust accumulating quantity calculator which determines a quantity of the dust in the container based on the pressure detected.

Abstract: A sensor for detecting particulate matter in an exhaust stream of an engine. The sensor may be a spark-plug-like device having an extended center electrode composed of a stainless steel or other material. The electrode may have a thin passivating layer formed on it. The layer may be grown or deposited on the electrode within the exhaust system. The sensor may detect charge transients indicative of particulate concentration in the exhaust stream. Information about particulate matter in the exhaust system along with other engine information may be processed for controlling or adjusting parameters of the engine to affect the particulate matter in the exhaust system.

Abstract: A method for evaluating particle concentrations in the atmosphere of a clean room or of a machine mini-environment is described. The method includes exposing a test surface of a test substrate to the atmosphere for a test time, capturing an amount of particles at the test surface of the substrate at the end of the test time, analyzing the amount of captured particles, and comparing the analyzed amount of particles with a reference amount of particles from a reference substrate. An evaluation of the atmosphere of the room or environment can thus be accomplished in a relatively short time.

Abstract: Systems and methods for the detection of substances (particularly particulate substances) within mail pieces, specifically letters and other “flats” of mail. In particular, the systems and methods are for the detection of residues of Chemical or Biological Warfare Agents (CBWAs) which may be present within the mail pieces. The system is principally designed to be included as part of Dual Pass Rough Cull System (DPRCS) for the collection and detection of the residue when the contaminated mail piece first enters a mail facility and before it is intermingled with other mail pieces.

Abstract: The components of cigarette smoke, known until now, do not explain the overwhelming hazardous effects of smoking; this invention describes the isolation, identification and procedures for determination of the structure, properties and assay of a relatively stable major harmful oxidant (cs-oxidant) present in the cigarette smoke, the content of which is about 190±10 ?g per cigarette; the cs-oxidant alone almost quantitatively accounts for the oxidative damage of proteins produced by the aqueous extract of whole cigarette smoke, it is also responsible for the oxidative damage of DNA; since the cs-oxidant is relatively stable, it further explains the deleterious effects of the side stream smoke and passive smoking; a number of chemical compounds/agents including vitamin C have been found to prevent the cs-oxidant induced protein oxidation in vitro.

Abstract: Particulate collector is carried onto airplane and collects suspended particulate matter in the atmospheric air in such a manner that suspended particulate matter is electrically charged by single-pole ions generated by a discharge electrode and the thus electrically charged particulates are attracted to a collecting electrode having an electric potential difference with respect to the discharge electrode so that the particulates are collected by the collecting electrode. The particulate collector is conveyed to an arbitrary altitude and driven so as to collect suspended particulate matter contained in the atmospheric air at the arbitrary altitude. Particulate collector is recovered onto the ground so as to make various measurements or the thus collected particulate collector is subjected to various measurements on airplane.

Abstract: A method that allows an individual to personally test for contaminants in an air supply. The method consists of purchasing the test kit, mounting the test kit to an existing particulate filter, placing the mounted test kit and particulate filter into the filter housing and blowing air through the test kit. The test kit is then removed from the furnace, repackaged and sent to a laboratory for analysis. The air quality test kit comprises a test filter, a filter backing pad, a support and a pair of end caps. The test filter, the filter backing pad and the support form a device to capture and retain particles carried in an airflow.

Abstract: A diffusion status prediction method and system for a diffused substance are disclosed. The diffused substance is replaced by particles, and positions which the particles generated from an emission source arrive at are found by computation. The arrival positions and a post-emission elapsed time are recorded in association with each other. Also, intensity data showing the intensities of the particles during the passage of the post-emission elapsed time are set. Then, the intensity of the particles at the point in time at which the particles were generated is found by reference to the intensity data based on the post-emission elapsed time. For each particle, the arrival position, the post-emission elapsed time, and the intensity are recorded in association with each other. The concentration of the diffused substance in a predetermined area after a lapse of a predetermined time can be determined by adding up the intensities of the particles present in the predetermined area.

Abstract: A contaminant detection system for mail is provided. A tray of mailpieces is transported along a transport path into a chamber that has a negative pressure maintained by a vacuum system. The tray of mail enters the chamber and is quickly decelerated, such as, for example, by hitting a stop. The quick deceleration compresses the mailpieces in the tray, thereby ejecting air, dust and other particles from the mailpieces into the surrounding environment inside of the chamber. The vacuum system draws the ejected air, dust and other particles into a sampling system that monitors for the presence of a possible biohazard. If any type of contaminant is found in the ejected air, dust and other particles, the tray can be held for further investigation of the mailpieces. If no contaminants are detected, the tray is accepted and the mailpieces are further processed.

Abstract: A automatic system for the capture, weighing and expulsion of solid particles, consisting of an airtight weighing chamber, inside which there is an inner container in which the particles entering the chamber through an entrance duct are collected. Said container transmits its weight to a weighing sensor, also located inside the weighing chamber but not in contact with the walls of the chamber. Once weighed, the sample is expelled from the chamber by the injection of compressed air. The system can be directly applied to determine the mass flow of solid particles in pneumatic transport ducts by integrating it into automatic sampling systems, and also gives a signal which can be integrated in regulating loops for the control of said flow.

Abstract: A method and a device for measuring properties of a particle distribution, in which a parameter relating to the mobility of the particles is measured at one measuring point (302) and a parameter relating to the aerodynamic size of the particles is measured at a second measuring point (305). By means of the measured parameters, at least one property of the particle distribution of the original flow is determined (306).

Abstract: A condensation nucleus counter has a series of flow passageways forming a flow path, including a first passageway for carrying the gas stream having the particles to be detected which is preferably preheated A saturator is positioned to receive the flow of the gas stream and is made of a porous material of a controlled pore size having a portion immersed in a liquid working fluid. The liquid working fluid moves by capillary action along the length of the saturator. Vapor from the working liquid will be transferred to the gas stream as it moves through the saturator. The gas stream then passes to a condenser that reduces the temperature of the gas stream and causes the working fluid vapor to condense on the particles in the gas stream to form droplets that can be detected and counted.

Abstract: Methods and apparatus are disclosed for measuring, collecting and responding to the measured amounts of particulate matter in a flowing air stream. Air stream filtering collects particulate matter on the filter media. At some point the collected particulate matter can clog the filter to the point where it can reduce the air flow to less than desirable levels or even block air flow to cause over heating or other dangerous conditions to occur. A fully automated and self checking electronic system is provided to monitor and control apparatus and to cause alarm or shutoff signals to be generated.

Abstract: A dust sampling device having a sampling nozzle is provided. The nozzle is provided with an inlets the diameter of which is variable. The diameter of the nozzle can be instantaneously changed, while keeping constant a sampling flow rate within a measuring device as the nozzle is introduced into a chimney or a duct in response to a change in flue gas flow velocity, to thereby maintain an uniform sampling rate in the nozzle. The nozzle is connected to a dust measuring device and is inserted into an interior of an flue gas passage. The diameter of the nozzle can be changed so as to keeping sampling gas flow rate determined by the dust measuring device constant at the sampling velocity corresponding to the flow velocity of the flue gas. The flue gas sampled through the nozzle is introduced into the dust measuring device.

Abstract: A method and apparatus for characterizing particulate matter in gases emitted from the exhaust tailpipe of a moving vehicle includes providing a micro-dilution device on the vehicle and, while the vehicle is moving, retrieving samples of the gases and mixing the samples with ambient air with the micro-dilution device, thereby forming diluted samples of the gases containing volatile and non-volatile particulate matter. A particulate analyzer is provided on the vehicle which measures at least one parameter of the volatile and non-volatile particulate matter.

Abstract: An apparatus for real-time measurement of mass, size and number of solid particles of particulate matter in engine exhaust has a catalytic stripper to remove at least about 90% of a volatile fraction of the particulate matter and pass at least about 95% of a solid fraction of the particulate matter, and a micro-dilution tunnel to cool the test medium after passing through the catalytic stripper and prior to passing through a particle sizer and counter system. A method embodying the present invention includes removing a volatile fraction of the particulate matter carried in a sample test stream and comparing the sample after removal of the volatile fraction with a second sample in which the volatile fraction has not been removed. The difference between the two samples represents liquid phase of the volatile fraction of the tested exhaust gas.

Abstract: An integrated fluidics system for simplified analysis of aerosolize biological particles has a unitary self-contained ticket provided with a sample fluid reservoir, an array of particle-detection strips, which is located adjacent to the sample reservoir, and, optionally, a cleaning fluid reservoir and an impinging nozzle. The fluidics system is, thus, configured to substantially minimize the fluid paths between the components of the system.

Abstract: The present invention relates to a pozzolanic admixture containing ammonia-laden fly ash, method for making the pozzolanic admixture and method for controlling ammonia gas (NH3) emission from cementitious slurries using the pozzolanic admixture. The associated hypochlorite and ammonia reaction produces monochloramine and chloride salts at relatively low concentration levels harmless to concrete and concrete applications. The resulting monochloramine and chloride salt products are stable and do not dissipate into the air, thereby, eliminating odorous emission that is produced from cementitious slurry containing untreated ammonia laden fly ash.

Abstract: A process to determine aerosol particles in gaseous samples, specifically in the exhaust of diesel motors, includes the at least indirect deposit of aerosol particles on a piezoelectric oscillating crystal and the determination of the oscillation parameters of the piezoelectrically stimulated oscillation of the crystal. In order to assure the required reproducibility reliably and independently of the type of aerosol particles, and thus to achieve a high quality of measurements, the piezoelectric crystal is charged to oscillation during less than half the period of deposit of aerosol particles.

Abstract: The components of cigarette smoke, known until now, do not explain the overwhelming hazardous effects of smoking; this invention describes the isolation, identification and procedures for determination of the structure, properties and assay of a relatively stable major harmful oxidant (cs-oxidant) present in the cigarette smoke, the content of which is about 190±10 &mgr;g per cigarette; the cs-oxidant alone almost quantitatively accounts for the oxidative damage of proteins produced by the aqueous extract of whole cigarette smoke, it is also responsible for the oxidative damage of DNA; since the cs-oxidant is relatively stable, it further explains the deleterious effects of the side stream smoke and passive smoking; a number of chemical compounds/agents including vitamin C have been found to prevent the cs-oxidant induced protein oxidation in vitro.

Abstract: A safety vacuum cleaner including a measuring system for residual dust monitoring, including a housing having an air passage with an inlet, an outlet, and a flow cross section. A turbine is disposed within the air passage and is rotatable to move an air stream through the air passage, the air stream containing dust particles. The turbine is electrically grounded such that electrical charges associated with the particles are removed upon contact of the particles with the turbine. A filter element is disposed within the air passage, and at least one electrode is disposed within the air passage downstream of the turbine, the electrode shaped as a grid covering the flow cross section of the air passage. The electrode conducts an electrical current responsive to contact with uncharged particles and emits a measurement signal indicative of the amount of the particles in the air stream.

Abstract: The invention relates to an automatic system for collecting, weighing and releasing solid particles comprising a leak-tight weighing chamber (1) which houses a container (5), whereon the particles entering said chamber (1) via an inlet (4) come to rest. The weight of the container (5) is transmitted to a weighing sensor (7) which is also located inside the weighing chamber (1) but which does not come into contact with the walls of said chamber. Once the sample has been weighed, it is removed from the chamber through the injection of compressed air. The inventive system can be used directly to determine the mass flow of solid particles in pneumatic conveyor lines by means of the integration thereof in automatic sampling systems. For this purpose, a signal is emitted which can be integrated in flow regulation loops in order to control said flow.

Abstract: A method and system for identifying, visually tracking and recording a moving vehicle exceeding a predetermined level of particulate emissions, the method including the steps of: detecting the particulate emissions of the vehicle at a first detection station; detecting the particulate emissions of the vehicle at a second detection station downstream of the first station; recording information identifying the vehicle if the detected emission of the vehicle at either station exceeds the predetermined level; and comparing the recorded information from both stations and identifying the vehicle if its identity appears in the recorded information for both stations and providing video tracking of the identified vehicle for an extended time period.

Abstract: An apparatus for real-time measurement of mass, size and number of solid particles of particulate matter in engine exhaust has a catalytic stripper to remove at least about 90% of a volatile fraction of the particulate matter and pass at least about 95% of a solid fraction of the particulate matter, and a micro-dilution tunnel to cool the test medium after passing through the catalytic stripper and prior to passing through a particle sizer and counter system. A method embodying the present invention includes removing a volatile fraction of the particulate matter carried in a sample test stream and comparing the sample after removal of the volatile fraction with a second sample in which the volatile fraction has not been removed. The difference between the two samples represents liquid phase of the volatile fraction of the tested exhaust gas.

Abstract: A diluter includes a filtering assembly and an intake assembly. The filtering assembly has a top cap that is provided with a first connector and a first through hole defined through the top cap, a lower cap having a second connector, a second through hole defined through the lower cap and an assembly hole defined to communicate with the second through hole, and a tubular filter securely connected between the top cap and the lower cap to form a mixing zone in communication with the first and the second through holes. The intake assembly having a first end and a second end, the first end being defined with a receiving hole to correspond to the first connector and the second end being provided with an inlet to communicate the first end and the second end.

Abstract: A system and method for collecting sub-hourly ambient particulate matter samples at flow rates of 170-260 L/min is suitable for either on- or off-line near-real-time multielement analysis by graphite furnace atomic absorption spectrometry and other techniques for which a sample in slurry form is advantageous. Condensational growth of water vapor was used to grow fine particles by steam injection. The grown droplets are concentrated using a virtual impactor, then separated from the airstream using a real impactor. The particles are collected in a liquid slurry which is hydraulically delivered to sample vials every 30 minutes for offline analysis, or directly delivered into the graphite furnace for atomic absorption spectrometry analysis.