The invention relates to a method for in-situ measurement of the concentration of gaseous chemical species contained in a biogas (10) flowing in a pipe (20), for example in a biogas treatment plant or a system using biogas.

The method according to the invention is implemented by means of an optical measurement system (40) including a light source (41) and a spectrometer (44). Source (41) emits a UV radiation (42) through the biogas (10) within a measurement zone (21) in the pipe. Spectrometer (44) detects at least part of said UV radiation that has passed through biogas (10) and it generates a digital signal of the light intensity (50) as a function of the wavelength of the part of the UV radiation that has passed through the biogas. The chemical species concentration is then determined from digital light intensity signal (50).

The present invention is an energy efficient air purification system 100 for purifying a complex polluted environmental air condition. The air purification system 100 includes a plurality of air pollution monitoring units MU.sub.1, MU.sub.2, MU.sub.3, MU.sub.4 . . . MU.sub.N which are installed at distant locations, a plurality of air purification units PU.sub.1, PU.sub.2, PU.sub.3, PU.sub.4 . . . PU.sub.N which are installed at distant locations and an automated control unit 500. The air pollution monitoring units are adapted to monitor the quality of the air in their surroundings. Upon such monitoring, the air pollution monitoring units are adapted to communicate the air quality data to the automated control unit 500. The automated control unit 500 is adapted to analyze the air quality data and on basis of such analysis, the automated control unit 500 further instructs the air purification units for further action.

An air quality notification device is disclosed. The air quality notification device includes an actuating and sensing module, a microprocessor, a first communication module and a power source. The actuating and sensing module includes a sensor and an actuating device. The actuating device is disposed near the sensor. The sensor senses air transmitted by the actuating device to generate air quality information. The microprocessor is electrically connected to the actuating and sensing module. The first communication module is electrically connected to the actuating and sensing module to receive and transmit the air quality information. The power source is electrically connected to the microprocessor.

A nanomaterial-based gas sensor system comprising a low voltage circuitry which includes a transducer to detect changes in electrical properties of a multi-channel gas sensor array, analog signal conditioning, and an A/D conversion to provide a signal to a digital back-end.

A system for the maritime shipping industry to aid enforcement of the Sulfur Dioxide (SO.sub.2) exhaust emissions regulations which uses neural networks and a novel sampling process to detect and record compliant operation of a ship regarding the fuel switching aspect of the regulation. The processing load of neural network training can be distributed over multiple identical self-contained, self-powered, self-communicating sensor units on each of the monitored ships.

A gas sensor includes: a sensor surface on which a metal-oxide film grows; a detection unit configured to detect a change in a resistance value of the metal-oxide film; and a computation unit configured to compute a quantity of reducing gas in measurement-target air based on a result of the detection by the detection unit, wherein the gas sensor operates in a first mode in which the gas sensor stands by with standby air, which differs from the measurement-target air, being in contact with the sensor surface immediately after the gas sensor is activated and in a second mode that follows the first mode and in which, the detection unit detects a change in the resistance value, and the computation unit computes the quantity of the reducing gas based on the result of the detection, with the measurement-target air being in contact with the sensor surface.

A system and method for monitoring air quality is disclosed. A housing for an electronic display has a first pathway which extends between an ingestion area and an exhaustion area. An air quality monitoring device is located along said pathway and has one or more sensors that measure the concentration of various gases. The air quality monitoring device has a housing with a second pathway which connects an entrance aperture to exit aperture. The entrance aperture being configured to permit a portion of the ambient air in the first pathway to enter the second pathway.

Processes, compositions, and sensors for sensing a variety of toxic chemicals based on colorimetric changes. Exemplary process for sensing a toxic chemical includes contacting a toxic chemical, or byproduct thereof, with a sorbent that includes a porous metal hydroxide or a porous mixed-metal oxide/hydroxide and a transition metal reactant suitable to react with a toxic chemical or byproduct thereof. The sorbent is contacted with the toxic chemical or byproduct thereof for a sampling time. A difference between a post-exposure colorimetric state of the sorbent and a pre-exposure colorimetric state of the sorbent is determined to thereby detect exposure to, or the presence of, the toxic chemical or byproduct thereof.

Processes, compositions, and sensors for sensing a variety of toxic chemicals based on colorimetric changes. Exemplary process for sensing a toxic chemical includes contacting a toxic chemical, or byproduct thereof, with a sorbent that includes a porous metal hydroxide or a porous mixed-metal oxide/hydroxide and a transition metal reactant suitable to react with a toxic chemical or byproduct thereof. The sorbent is contacted with the toxic chemical or byproduct thereof for a sampling time. A difference between a post-exposure colorimetric state of the sorbent and a pre-exposure colorimetric state of the sorbent is determined to thereby detect exposure to, or the presence of, the toxic chemical or byproduct thereof.

A method of directly measuring SO.sub.2 and other trace gases by configuring an electrochemical cell (ECC) sonde; and an ECC sonde pump inlet filter to remove ozone and other trace gases. Further, calibration and operation procedures for the SO.sub.2 and other trace gas ECC sondes are disclosed.