Abstract: A gas sensor configured to detect a target gas in a gaseous atmosphere, for example NO2 or O3 in air, comprises: a transparent substrate; a gas sensitive detection layer supported by the transparent substrate, the gas sensitive detection layer comprising i) a gas sensitive detection material having an electrical impedance which is sensitive to the target gas and ii) connections configured to allow for detection of electrical impedance of the gas sensitive detection material; and a light source, for example a LED, configured to provide light to the gas sensitive detection layer through the transparent substrate. The gas sensor may operate at room temperature whilst requiring little power.

Abstract: The present invention relates to gas sensors, in particular, to an optical fibre sensor for measuring the presence and/or quantity of one of more gasses, the gas sensor comprising an optical fibre, and a gas sensitive detection material at a portion of the surface of the optical fibre, said gas sensitive detection material comprising a gas sensitive reactant and a porous matrix, wherein the gas sensitive detection material undergoes a reversible change of reflectance and/or absorbance at a detection wavelength when subjected to a gas to be detected.

Abstract: A sensor for gases emitted by combustion, the sensor involving one or more metal oxides forming an adsorption semiconductor the electrical resistance of which changes according to the gas adsorbed, the semiconductor being a semiconductor for the direct adsorption of gases without catalyzed chemical reaction, the sensor being arranged to detect nitrogen oxides in the case of a bright fire, and/or the sensor being arranged to detect, in the case of a smoldering fire, partially unburned gases, in particular alcohols, aldehydes, ketones, carboxylic acids or amines.

Abstract: A sensor for gases emitted by combustion, said sensor comprising one or more metal oxides forming an adsorption semiconductor the electrical resistance of which changes according to the gas adsorbed, said semiconductor being a semiconductor for the direct adsorption of gases without catalyzed chemical reaction, said sensor being arranged to detect nitrogen oxides in the case of a bright fire, and/or said sensor being arranged to detect, in the case of a smoldering fire, partially unburned gases, in particular alcohols, aldehydes, ketones, carboxylic acids or amines.