Abstract: Systems and methods for collecting portions of a target sample are disclosed herein. A method for detecting the presence and/or properties of a target sample can include selectively collecting a portion of a target sample with a sample collector and detecting, with the sample collector, the presence of one or more properties of the microscopic portion of the target sample. The method also includes analyzing, with the sample collector, the one or more properties of the microscopic portion of the target sample. Based on the analysis, the method further includes reporting, from the sample collector, a real-time indication of the analysis of the one or more properties of the target sample. The method can also include at least partially removing the microscopic portion of the target sample from the sample collector.

Abstract: A smoke detector has a housing, a smoke sensor in the housing capable of detecting smoke therein, and an alarm connected to the sensor signaling when the smoke sensor detects smoke. A partition subdivides the housing into separate first and second chambers, and the housing is formed with first and second smoke holes allowing air from the exterior into the first and second chambers. The partition has a sensor port provided with a sensor for detecting air flow through the sensor port and a fan port having a fan for drawing air from one of the chambers and forcing it into the other chamber. A controller connected to the fan and to the air-flow sensor operates the fan means to move air from the one chamber through the fan port into the other chamber and generates an output when air flow through the sensor port exceeds a predetermined limit.

Abstract: A chemochromic sensor for detecting a combustible gas, such as hydrogen, includes a chemochromic pigment mechanically mixed with a polymer and formed into a rigid or pliable material. In a preferred embodiment, the chemochromic detector includes aerogel material. The detector is robust and easily modifiable for a variety of applications and environmental conditions, such as atmospheres of inert gas, hydrogen gas, or mixtures of gases, or in environments that have variable temperature, including high temperatures such as above 100° C. and low temperatures such as below ?196° C.

Abstract: Provided are an environmental gas sensor and a method of manufacturing the same. The environmental gas sensor includes an insulating substrate, metal electrodes formed on the insulating substrate, and a sensing layer in which different kinds of nanofibers are arranged perpendicular to each other on the metal electrodes. Thus, the environmental gas sensor can simultaneously sense two kinds of gases.

Abstract: A system and method for closed-loop testing of a biological or chemical sensor is disclosed. The tester is fluidically coupled to the input port and exhaust port of a sensor. A mixture of a chemical or biological simulant and air is generated by the tester and is delivered to the sensor. The mixture of simulant and air exiting the sensor is delivered to a collection device.

Abstract: The invention is a method and system of screening the content of an enclosure, such as a cargo container, for the presence of one or more target substances, such as explosives or drugs, comprising drawing air from the enclosure and passing the drawn air across at least one sampling card having a coating configured to absorb/adsorb the one or more target substances and thereafter analyzing the sampling card to determine if the coating has absorbed/adsorbed one or more target substances. The system embodiment includes a vacuum source, a conduit coupled to the vacuum source and a sampling card holder disposed along the conduit. The sampling card holder removably holds at least one sampling card having a coating thereon configured to absorb/adsorb the one or more target substances, so that air drawn into the conduct from the enclosure passes across the at least one sampling card.

Abstract: A technology for collecting a granular substance adhering to a baggage with high rate without touching the substance and inspecting whether a dangerous or specific sample material is adhered to the baggage. A method for simplifying or automating such an inspection is also provided. An adhering matter inspection equipment (1) is characterized in that the equipment comprises a collecting section (5) for collecting a sample material peeled off from an inspection object (25) whereupon the sample material is adhered by blowing compression gas through a capturing filter (52), and an inspecting section (2) for analyzing the sample material captured by the capturing filter (52), and further characterized in that the inspection equipment comprises a section (3) for delivering a baggage to the inspecting section (2), and a carrying section (4) for carrying the capturing filter (52) from the capturing section (5) to the inspecting section (2).

Abstract: The illustrative embodiment of the present invention is a system and a method for the detection and limited identification of biological agents. The system is small, light weight, requires little power to operate and uses few consumables. The system can be configured for use in either stationary or mobile applications. The system incorporates elements that enable it to obtain an air sample, extract particulates from the air sample, exposes the particulates to electromagnetic radiation, and monitor for fluorescent emissions. To the extent that fluorescent emissions are detected and exceed a predetermined value, an alarm is triggered.

Abstract: Disclosed are means for monitoring the levels of air pollution in urban areas for the purpose of optimizing the conditions of airflow ventilation of buildings according to air pollution levels in their area. The invention supplies data in real time regarding local air pollution levels or relative levels, i.e. current air pollution levels in relation to previous ones. The disclosed system and method makes use of the fluctuations in air pollution levels in order to achieve optimal reduction of air pollution levels inside buildings. The system defines optimal times for ventilation in order to achieve a significant and persisting improvement of indoor air quality, in a routine manner, by using measurements of nondeterministic, continuous and effective fluctuations in air pollution levels at the surroundings of each building, specifically in locations which don't include monitoring stations.

Abstract: A method is proposed for characterizing a totality of particles. The method can be used in particular for characterizing microparticular or nanoparticular aerosols. The method comprises the following steps: a) in a classification step, a class of the totality is selected, wherein the particles of the selected class have a prespecified mobility dm; b) in a counting step, a number N of the particles of the selected class is determined; c) in a charge determination step, a charge Q of the particles of the selected class is determined; and d) in an evaluation step, at least one morphological parameter is determined from the charge Q, the number N and the mobility dm, wherein the morphological parameter comprises at least one item of information about an agglomerate state of the particles.

Abstract: A re-calibration method for a dual-beam NDIR gas sensor uses a calibration curve based upon a combination of physics and sensor measurement components of the sensor to calculate sample gas concentration, then determines a second gas concentration measurement by a secondary gas standard which is used with a reversed calibration curve algorithm to adjust the sensor measurement component. The calibration curve is based upon a gamma ratio (“G”) that has been normalized by G when no sample gas is present in the sample chamber (“G0”), G being a ratio of a signal channel output (“VS”) of the sensor divided by a reference channel output (“VR”) of the sensor. The concentration (“P”) of sample gas in the sensor is calculated through use of the calibration curve by a gas detection equation of P=F(x)=F(y/G0), where x is a normalized ratio of VS/VR and y is G.

Abstract: A device for use with a detection means and a solvent source for sampling low volatility hazardous chemicals within a sample matrix is comprised of a sonicator having a probe for providing mechanical agitation to the sample matrix; means for transporting solvent gas from the solvent source to the sample matrix; means for transporting sample gas from the sample matrix to the detection means; and a heating element for heating the sample gas, solvent gas, and sample matrix. The device may include a thermocouple for providing a temperature reading. It also may include a plurality of interchangeable probe tips of different shapes.

Abstract: A gas detector and process for detecting a fluorine-containing species in a gas containing same, e.g., an effluent of a semiconductor processing tool undergoing etch cleaning with HF, NF3, etc. The detector in a preferred structural arrangement employs a microelectromechanical system (MEMS)-based device structure and/or a free-standing metal element that functions as a sensing component and optionally as a heat source when elevated temperature sensing is required. The free-standing metal element can be fabricated directly onto a standard chip carrier/device package so that the package becomes a platform of the detector.

Abstract: Various screening systems are disclosed, including a system including a radiation detection component, a toxic chemical detection component, a toxic chemical agent sampling component, a bio-threat detection component, a puffer-based bio-threat sampling component, an explosive detection component, and an X-ray based imager, such that it automatically screens mail for the presence of multiple threat agents, such as chemical, biological, radiological, nuclear and explosive threats. An automated sample arm collects a sample when a sampling substrate contacts a portion of the item of mail while there is relative motion between the automated sample arm and the item of mail. The sample is conveyed to a detector and the sampling substrate is regenerated by heating it.

Abstract: A method and system for estimating an air quality condition based on vehicle data received from surrounding vehicles is disclosed. The method includes a step of determining a dynamic traffic pattern from the received vehicle data to determine a level of congestion. The method also includes a step of estimating the air quality condition based on the dynamic traffic pattern. The method and system further includes adjusting one or more settings of a cabin air control system based on the estimated air quality condition.

Abstract: A single chip wireless sensor comprises a microcontroller connected to a transmit/receive interface, which is coupled to a wireless antenna by an L-C matching circuit. The sensor senses gas or humidity and temperature. The device is an integrated chip manufactured in a single process in which both the electronics and sensor components are manufactured using standard CMOS processing techniques, applied to achieve both electronic and sensing components in an integrated process. A Low-K material with an organic polymer component is spun onto the wafer to form a top layer incorporating also sensing electrodes. This material is cured at 300° C., which is much lower than CVD temperatures. The polyimide when cured becomes thermoset, and the lower mass-to-volume ratio resulting in K, its dielectric constant, reducing to 2.9. The thermoset dielectric, while not regarded as porous in the conventional sense, has sufficient free space volume to admit enough gas or humidity for sensing.

Abstract: A feeding device for enriching and feeding a fluid sample into a chemical detector, the feeding device comprises (a) a sorbent element having a sorbent material for sorbing at least one target chemical present in the fluid sample; (b) a desorbing mechanism for generating conditions for the sorbent material to desorb the at least one target chemical out of the sorbent material, thereby to provide an enriched fluid sample; and (c) a loose connector, for providing a loose connection between the feeding device and the chemical detector, such that when the sorbent material desorbs the at least one target chemical, the chemical detector is fed by the enriched fluid sample, and when the sorbent material sorbs the at least one target chemical, the chemical detector is fed by environmental fluids.

Abstract: This invention describes a sample collection method that could release and collect residues of explosives and other chemicals from a surface; the described method is implemented into a compact detection system that can be used as a “wand” for screening chemicals residues on a subject. The wand configuration includes multi-function for sampling and detecting multiple threads. The invention further describes a method of inspecting a subject using an interrogating apparatus in a sweeping motion; the near range closed loop particle sampling arrangement allows effective collection of particle and vapor residues from a targeted surface. The invention also describes a sampling and detecting apparatus for on-the-fly threat detection using compact ion mobility based detectors.

Abstract: A sensor for detecting and differentiating chemical analytes includes a microscale body having a first end and a second end and a surface between the ends for adsorbing a chemical analyte. The surface includes at least one conductive heating track for heating the chemical analyte and also a conductive response track, which is electrically isolated from the heating track, for producing a thermal response signal from the chemical analyte. The heating track is electrically connected with a voltage source and the response track is electrically connected with a signal recorder. The microscale body is restrained at the first end and the second end and is substantially isolated from its surroundings therebetween, thus having a bridge configuration.

Abstract: A process and sensor device are disclosed that employ metal ?-diketonate polymers to selectively capture gas-phase explosives and weaponized chemical agents in a sampling area or volume. The metal ?-diketonate polymers can be applied to surfaces in various analytical formats for detection of: improvised explosive devices, unexploded ordinance, munitions hidden in cargo holds, explosives, and chemical weapons in public areas.

Abstract: A process and sensor device are disclosed that employ metal ?-diketonate polymers to selectively capture gas-phase explosives and weaponized chemical agents in a sampling area or volume. The metal ?-diketonate polymers can be applied to surfaces in various analytical formats for detection of: improvised explosive devices, unexploded ordinance, munitions hidden in cargo holds, explosives, and chemical weapons in public areas.

Abstract: The invention relates to a method and a device (16) for detecting volatile analytes in air samples, where a masssensitive sensor (20) with at least one sensor area (21) which is equipped with a surface layer with selective sensitivity for the analyte(s) to be detected is brought into contact with the air sample to be analyzed, the mass change of the surface layer is detected in the form of electrical signals and the electrical signals are evaluated. It is provided in accordance with the invention that the sensor signal is already evaluated at a point in time at which the maximum sensor signal for the analyte concentration in question is not yet obtained.

Abstract: A detector for the detection for trace vapors and particles in the air that includes a housing; a well formed in the housing; a heated filter positioned across the well; a source delivering sampled air substantially perpendicular to the open end of the well on a first side of the filter; a source to supply dry air across the first side of the filter; a detector line in communication with the at least one well on a second side of the filter; and a second dry air source for supplying air to the second side of the filter at a pressure below atmospheric pressure. An automatic inspection station that includes a vibrator for vibrating articles to be inspected. An automatic inspection station that includes a heating element positioned below an upper surface of the floor and an inlet positioned above the floor.

Abstract: A planar electrochemical gas sensor is provided with at least one working electrode (4), at least one counterelectrode (4?), at least one electrolyte-filled planar electrolyte carrier (10), at least one planar housing upper part (3) and at least one planar housing lower part (2). The electrodes (4, 4?) are arranged such that they are in two-dimensional contact with the electrolyte carrier (10). The housing upper part (3) and the housing lower part (2) are connected with one another such that the electrodes (4, 4?) and the electrolyte carrier (10) are pressed against one another in such a way that they are secured against displacement. The housing upper part (3) and the housing lower part (2) are partially in direct two-dimensional contact with one another, and the connection of the housing upper part (3) and the housing lower part (2) in the area of the direct two-dimensional contact is present at least along a closed figure, which surrounds the electrodes (4, 4?) and the electrolyte carrier (10).

Abstract: The design and synthesis of a matrix nanocomposite containing amino carbon nanotubes used as a functionalized sensing layer for carbon dioxide detection by means acoustic wave sensing devices, e.g., SAW/BAW devices. These sensing materials contain a type of amino carbon nanotubes (single walled or multi-walled) and a polymer (or other compounds) which are sensitive to carbon dioxide in the acoustic wave sensing device based gas sensors. The sensitivity of the matrix consisting of the amino carbon nanotubes and a polymer (or other compounds) is ensured by the presence of amino groups which can react at room temperature with CO2 in a reversible process to form carbamates.

Abstract: A gas sensor assembly detects a constituent in a gaseous stream. The assembly comprises: (a) a mounting surface, (b) a sensor mounted on the mounting surface and sensor capable of generating a detectable signal in the presence of the constituent, and (c) an enclosing structure. The enclosing structure comprises: (i) a walled component having a pair of vertically spaced ends and mounted at one end on the mounting surface so as to circumscribe the sensor, and (ii) a gas-permeable membrane attached at the other end of the walled component, thereby defining an interior volume within said enclosing structure. Flowing the gaseous stream across the membrane infuses a portion of the gaseous stream into said interior volume containing the sensor.

Abstract: A device for detecting chemical or biological substances includes an analytical instrument for detecting the substances and for providing information concerning the qualitative or quantitative presence of the substances, and also a contamination sensor for measuring the degree of contamination of the analytical instrument and/or of the device.

Abstract: The present invention provides a device that measures at least one property of the liquid or gas, where the invention is a CMUT sensor that includes a substrate, a first layer disposed on the substrate, where the first layer includes a cavity, and a compound plate, where the compound plated includes a bottom plate, an intermediate plate and a top plate. According to the invention, the intermediate plate has at least one sample inlet, a sample cavity and at least one sample outlet, where the bottom plate is disposed on the first layer, and the cavity in the first layer is sealed by the compound plate. The cavity in the first layer can be a vacuum or contain a gas. The CMUT sensor can be disposed in an array of two or more sensors and connected electrically in parallel.

Abstract: An environmental monitoring system and methods of a site are disclosed. The system includes one or more environmental measurement instruments, of which at least one instrument is capable to measure a concentration of particles in a certain size range. The system may also include an instrument that is capable of measuring a first concentration of particles in a first size range and a second concentration of particles in a second size range. The system may also include an instrument that is capable to measure a wind speed and a wind direction. The system may also include one device capable of recording an image of a location related to the site. The system includes a controller in communication with the one or more environmental measurement instruments, and a display device capable of displaying data generated by the one or more environmental measurement instruments. The system contains a network. Alerts can be provided based on conditions of the environment.

Abstract: Provided is a sensor structure comprising a heater and a temperature sensor at the center of a membrane having a well structure, allowing a temperature to be rapidly controlled with low power, and the object is analyzed using a conductivity change measured at two or more substrate temperatures with a pair of detecting electrode and a detecting layer implemented on the heater, wherein the sensing layer can include a conductive particle and a non-conductive organic composite.

Abstract: A method for collecting and sensing a column of air in near real-time to detect one or more agents dispersed within the air column is described. The method includes passing the column of air through a port in a parafoil, the parafoil configured with a flow-through sensor suite located in the port and operable such that the column of air passes through the sensor suite, operating the sensor suite to test the column of air for the one or more agents, and receiving test results from the sensor suite.

Abstract: The present invention relates to the monitoring of gas concentrations possible in very low ranges (i.e., low ppb and even ppt ranges) and especially use thereof in environmental monitoring, exposure assessment, bomb detection, and health studies. The invention can use a spatial and temporal assessment of gas concentrations that enables the sources of the gas in question to be located and identified which is useful in environmental and health field but can also be applied to other fields an example of which is detecting and locating explosives. This technology can uses small, light weight, and low power components that allow for the monitor to be portable and even worn on a person as a personal monitor. This technology can be used in a stationary monitors as well.

Abstract: A pressure monitoring apparatus (10) including features that simplify in-situ calibration procedures. A pressure monitoring module (12) of the apparatus is coupled to external pressure lines (14, 16) and an external electrical interface (24) via an easily removable monitoring module plug (32). The monitoring module can be disconnected from the pressure lines and external interface and then connected to a portable calibration module (42) by simply replacing the monitoring module plug with a calibration module plug (50). The calibration module plug provides an electro-pneumatic interface between the monitoring module and the calibration module. The monitoring module may be electronically interrogated and automatically calibrated via a processor of the calibration module. The monitoring module plug may be inserted onto the calibration module plug to provide actual system pressures to the now-calibrated apparatus for final documentation.

Abstract: A collection and detection system is directed to a combined system in which a detect to warn system is integrated with a detect to treat system. Such a combined system provides multi-levels of detection to determine the presence and identity of one or more different types of specific particles. In some applications, the combined system is configured to detect and identify one or more different types of specific biological particles such as toxins and pathogens. The combined system includes a first level detection device, in which the presence of one or more toxins and/or pathogens are detected, and a second level detection device. Upon detection by the first level detection device, the second level detection device performs a second level of detection in which the one or more toxins and/or pathogens are identified.

Abstract: The radiation emitted by the various components in a sample of a fluid wherein the radiation emitted by activated molecules within the sample of the fluid is used to determine the nature of and quantities of materials present in the fluid and a fluid analyser system comprising a receptacle(s) and an analysis apparatus containing a consistent light condition compartment containing temperature detection device(s) into which the receptacle containing the fluid sample may be placed and means are provided for activating the molecules within the sample so that the radiation emitted by the sample may be detected and amplified.

Abstract: An aspirated smoke detector includes an ambient air flow separation element in combination with a smoke sensing chamber. The flow separation element can be an active or a passive element. Separated ambient, carrying relative small particles can flow into the sensing chamber. Ambient carrying relatively larger particulate matter is excluded from the sensing chamber.

Abstract: A gaseous product detecting device (1; 20; 30; 40; 70) has a measuring cell (6; 59; 60), a filtering element (3; 45) for retaining particulate present in the air entering the measuring cell (6; 59, 60), and a detecting element (13; 50, 56) housed inside the measuring cell (6; 59, 60). A wall (9; 49, 61; 79, 82) of the measuring cell (6; 59, 60) is movable in fluidtight manner between a withdrawn position, in which the measuring cell (6; 59, 60) has a maximum volume, and a forward position, in which the measuring cell (6; 59, 60) has a minimum volume and the detecting element (13; 50, 56) is prevented from being impressed by resting against a shutter surface (5a; 43a, 49b; 82a) of the measuring cell (6; 59, 60).

Abstract: A sensor including a tubular casing having an open rear end; and a first elastic member having a through hole so as to introduce ambient air into the casing and disposed so as to block the rear end opening of the casing.

Abstract: A hydrogen sensor (100) with instant response that uses one or more quartz tuning forks (101, 102) while no chemical reactions or other material modifications are involved. Sensor (100) can be used in any application to measure percent range of hydrogen concentrations.

Abstract: A compact sensor with which particles floating in the air can be easily detected. A sensor having a microstructure which detects a detection object by contact is used. A microstructure has an opening to be a detection hole corresponding to the size of a detection object, and a pair of electrodes having a bridge structure are provided thereabove or thereunder so as to partially contact with each other.

Abstract: A Computer Vision Chemical Detector has been developed that uses invertebrate organisms trained to respond to targeted chemical odors.

Abstract: The present invention provides a method and system for collecting and storing an atmospheric sample for eventual analysis, where the atmospheric sample includes a mixture of at least a matrix and an analyte. In one implementation, the system includes a housing; a sample cartridge removably attached to the housing, and a pump integrated with the housing and in fluid communication with the sample cartridge, the pump being configured to draw the atmospheric sample through the sample cartridge and to subsequently evacuate the matrix from the sample cartridge. The sample cartridge includes a low thermal mass cylinder with a first end and a second end; an inlet port with a gas-tight inlet valve at the first end of the cylinder, an outlet port with a gas-tight outlet valve at the second end of the cylinder, and a sorbent material disposed within the cylinder and adapted to trap the analyte from the atmospheric sample.

Abstract: A method for collecting and sensing a column of air in near real-time to detect one or more agents dispersed within the air column is described. The method includes passing the column of air through a port in a parafoil, the parafoil configured with a flow-through sensor suite located in the port and operable such that the column of air passes through the sensor suite, operating the sensor suite to test the column of air for the one or more agents, and receiving test results from the sensor suite.

Abstract: The present invention relates to an artificial throat for simulating aroma release comprising—a tube (1) having an inlet (2) and an outlet (3) and having an upper portion (4), a middle portion (5) and a lower portion (6);—a sample supply system (12) debouching at the upper portion of the tube;—an inlet closure (9) for closing and opening the inlet;—an outlet closure (10) for closing and opening the outlet;—a gas ventilation system (13) debauching at the lower portion of the tube for providing a gas flow, such as an air flow, through the tube. The invention also relates to an assembly for simulating and analyzing aroma release comprising an artificial throat and an analyzing apparatus, such as a mass-spectrometer. Furthermore the invention relates to a method for simulating and analyzing aroma release by means of an artificial throat. Aroma release according to the invention means the release of volatile compounds from substances such as food and drinks, which compounds are transported by means o a gas flow.

Abstract: A mail screening device for hazardous materials is disclosed. The mail screening device comprises a sample collection unit that uses air jets or air knives to dislodge residues of hazardous materials from a mail, and a detection unit that detects the hazardous materials in the exhaust air flow. Comparing to traditional mail screening systems that use belts and rollers to physically pinch a mail for sample collection, the device of the present invention is less complex and easier to operate, thereby reducing installation, maintenance and replacement costs.

Abstract: An environmental monitoring system and methods of a site are disclosed. The system includes one or more environmental measurement instruments, of which at least one instrument is capable to measure a concentration of particles in a certain size range. The system may also include an instrument that is capable of measuring a first concentration of particles in a first size range and a second concentration of particles in a second size range. The system may also include an instrument that is capable to measure a wind speed and a wind direction. The system may also include one device capable of recording an image of a location related to the site. The system includes a controller in communication with the one or more environmental measurement instruments, and a display device capable of displaying data generated by the one or more environmental measurement instruments. The system contains a network. Alerts can be provided based on conditions of the environment.

Abstract: An environmental monitoring system and methods of a site are disclosed. The system includes one or more environmental measurement instruments, of which at least one instrument is capable to measure a concentration of particles in a certain size range. The system may also include an instrument that is capable of measuring a first concentration of particles in a first size range and a second concentration of particles in a second size range. The system may also include an instrument that is capable to measure a wind speed and a wind direction. The system may also include one device capable of recording an image of a location related to the site. The system includes a controller in communication with the one or more environmental measurement instruments, and a display device capable of displaying data generated by the one or more environmental measurement instruments. The system contains a network. Alerts can be provided based on conditions of the environment.

Abstract: An environmental monitoring system and methods of a site are disclosed. The system includes one or more environmental measurement instruments, of which at least one instrument is capable to measure a concentration of particles in a certain size range. The system may also include an instrument that is capable of measuring a first concentration of particles in a first size range and a second concentration of particles in a second size range. The system may also include an instrument that is capable to measure a wind speed and a wind direction. The system may also include one device capable of recording an image of a location related to the site. The system includes a controller in communication with the one or more environmental measurement instruments, and a display device capable of displaying data generated by the one or more environmental measurement instruments. The system contains a network. Alerts can be provided based on conditions of the environment.

Abstract: In some embodiments, an oxygen concentrator may include lightweight injection molded housing components coupled to dual-pump diaphragm compressors. The oxygen concentrator may be coupled to a pressure transducer that detects a user's inhalation. The detected inhalation may signal the release of a bolus of oxygen. The sensitivity of the pressure transducer readings may be adjusted based on a detected environment. The user's breathing rate may also be determined to control the number of compressors used for increased efficiency. An ultrasonic sensor and gas flow rate meter may be used to determine an amount of oxygen being delivered to the user. Other components such as step valves and a solar panel may also be used to further conserve battery power. The oxygen concentrator may also incorporate an audio device such as a mobile phone.

Abstract: An aspirated smoke detector includes a flow path and a generator of acoustic waves in the flow path. Airborne particulate matter in the flow path responds to the acoustic field by particle agglomeration; the resulting larger particles flow into a photoelectric-type smoke sensor. A sensed level of particles can be processed, or compared to one or more predetermined thresholds to establish presence of one or more predetermined conditions.