In an illustrative configuration, a method for monitoring air quality is disclosed. The method includes accepting analyte gas into a cell and reflecting light rays into the analyte gas repeatedly across the cell into at least one sensor. The light scattered by particulate matter in the analyte gas and amount of spectra-absorption due to presence of a gaseous chemical is then measured. Based on the determined amount of spectra-absorption and the measured scattered light the gaseous chemical is then measured.

A measurement equipment for measuring gases and environmental parameters, made up of sensors (4) for measuring the parameters that influence air quality, odors, leak detection, fugitive emissions, pollutants, the presence of certain gases in the atmosphere, etc., having a housing (1) configured to incorporate removable cartridges (3) in which sensors (4) are housed, associated in an assembly unit with respective specific electronic boards (5) which are connected to a central electronic board (6) arranged in the housing (1) that recognizes the sensors (4). A cartridge (3) configured to be coupled to the measurement equipment for measuring gases and environmental parameters.

A compact explosive detecting system collects explosive residues in the form of vapor powder. The residues are accumulated on a desorber which is subjected to pyrolysis to release a gaseous sample. The sample is pumped to a detecting system through a metering valve. A luminol cell reacts with the gaseous sample to create chemiluminescence, the light output of which is measured by a photo multiplier tube. The light intensity is indicative of the amount of explosive present. Based on the amount of explosive present, a metering valve is adjusted to pass the gaseous sample into a highly sensitive metal oxide sensor array to detect NO.sub.2 from nitrogen containing explosive and CO/CO.sub.2 from non nitrogen containing explosive. The metal oxide sensor array reliably selects explosives from those compounds indicating chemiluminescence.

Among other things, this application describes systems and methods for detecting gas using a wide band light source, and at least two narrow band light sensors, wherein each sensor may be operable to detect light at a different range of wavelengths. Additionally, the gas detector device may comprise a color changing indicator operable to react with gas in the air to change color, wherein different gases may react to create different colors, and wherein the sensors detect light reflected by the color changing indicator from the wide band light source. The gas detector device may comprise a processor in communication with the at least two light sensors operable to receive detected reflected wavelength information from the light sensors, and determine the type of gas that reacted with the color changing indicator based on the color detected by the sensors, wherein each color may be associated with a different type of gas.

A system for detecting an analyte gas in an environment includes a first gas sensor, a first contaminant sensor separate and spaced from the first gas sensor, and electronic circuitry in electrical connection with the first gas sensor to determine if the analyte gas is present based on a response of the first gas sensor. The electronic circuitry is further in electrical connection with the first contaminant sensor to measure a response of the first contaminant sensor over time. The measured response of the first contaminant sensor varies with an amount of one or more contaminants to which the system has been exposed in the environment over time.

Ultrasensitive, ultrathin thermodynamic sensing platforms for the detection of chemical compounds at trace levels are disclosed. Embodiments of the ultrathin sensor comprise substrate, adhesion, microheater, and catalyst layers. A sensor array may include a plurality of sensors each having a different catalyst. When a sensor array exposed to an analyte, each of the various sensors of the array may experience an endothermic reaction, an exothermic reaction, or no reaction. A comparison of the reaction results to data comprising previously-obtained reaction results may be used to determine information on the analyte. Advantageously, these ultrathin vapor sensors utilize less power and provide greater sensitivity, and may be used to detect and identify analytes at the PPT level. Specialized sensors configured to detect analytes falling into a certain category (e.g., explosives, drugs and narcotics, biomarkers, etc.) are disclosed, as well as general purpose sensors capable of detecting analytes from a plurality of categories.

The present invention relates to a system for analysing volatile organic compounds (VOCs) in soil comprising an apparatus and a soil VOC sensor strip, wherein the apparatus comprises a sampling chamber for receiving soil, a sensor strip aperture in the sampling chamber for positioning the sensor strip in fluid communication with the sampling chamber, a power source and an electrical resistance detector, wherein the sensor strip comprises a flexible substrate with a first surface and an array of semiconductor polymer sensors arranged on the first surface, wherein each of the semiconductor polymer sensors comprises a pair of electrodes, wherein the pair of electrodes comprises a first electrode and a second electrode, wherein a semiconductor polymer is disposed between the first electrode and the second electrode, and wherein the sensor strip is electrically connectable to the power source and the electrical resistance detector.

A gas detection device according to an embodiment of the present invention includes a casing and a plurality of sensor elements. The casing includes a gas introducing port, a first chamber that communicates with the introducing port, a second chamber that communicates with the first chamber, a flow limiter that limits a flow of gas from the first chamber to the second chamber, and a gas exhausting portion that communicates with the second chamber. The plurality of sensor elements are disposed within the second chamber and have different detection sensitivities depending on a gas type.

Certain aspects of the present disclosure provide methods and apparatus for closed-loop control of a system using one or more electron paramagnetic resonance (EPR) sensors located on-site. With such EPR sensors, a change can be applied to the system, the EPR sensors can measure the effect(s) of the change, and then adjustments can be made in real-time. This feedback process may be repeated continuously to control the system.

Embodiments of the present disclosure relate to a method for detecting an air discharge decomposed product based on a virtual sensor array, comprising: fabricating a virtual sensor array; disposing the virtual sensor array in a hermetically sealed gas chamber, energizing, and initializing; performing gas-sensitive testing to the virtual sensor array and storing a testing result as samples to store; and building a convolutional neural network model diagram for identifying contents of gas components, and identifying an atmosphere. The virtual sensor array fabricated by the present disclosure may reduce the array size and the overall volume of a device to an extreme content; the built convolutional neural network may dig other feature information besides a response value from a response curve of a sensor, thereby effectively improving identification efficiency and identification accuracy.