Abstract: A gas analyzer and a corresponding method is provided to measure the concentration of formaldehyde within enclosed environments such as within buildings comprising an ultraviolet light source, a sample chamber, a detector. The detector measures the intensity of light received by photosensors within a measurement range of wavelengths, and at least one reference range of wavelengths. Advantageously, the concentration of formaldehyde is determined taking into account fluctuations in the intensity of light emitted by the light source, and in the presence of any interferents such as nitrogen dioxide.

Abstract: A gas analyser is provided to measure the concentration of formaldehyde within enclosed environments such as within buildings comprising an ultraviolet light source, a sample chamber, a detector. The detector measures the intensity of light received by photosensors within a measurement range of wavelengths, and at least one reference range of wavelengths. Advantageously, the concentration of formaldehyde is determined taking into account fluctuations in the intensity of light emitted by the light source, and in the presence of any interferents such as nitrogen dioxide. A method of measuring the concentration of formaldehyde in enclosed environments is also presented.

Abstract: An optical absorption gas sensor comprising a body having an internal wall which defines a chamber, at least one aperture in the body through which a gas sample can enter the chamber, a light source, at least one reflector, a detector assembly which extends into the chamber and has a first side and an opposite second side, a detector which measures light which is incident at least a range of angles on at least a part of a first surface of the detector assembly on the first side of the detector assembly, wherein the light source is located within the chamber on the second side of the detector assembly, the whole being configured such that light from the light source passes through the gas sample and is reflected around the detector assembly, by the at least one reflector, onto the detector.

Abstract: A flue gas analyser for measuring the concentration of oxygen in flue gas, comprising an electrochemical oxygen sensor and water vapour removing means for reducing the relative humidity of received gas and/or nitrogen-containing-gas removing means for removing from received gas one or more gaseous species comprising nitrogen and oxygen which are either nitrogen dioxide, or formed from nitrogen dioxide in the presence of sufficient water vapour, which would otherwise lead to damage of the electrochemical oxygen sensor,

Abstract: A fuel gas analyzer for measuring the concentration of oxygen in fuel gas, comprising an electrochemical oxygen sensor and water vapor removing means for reducing the relative humidity of received gas and/or nitrogen-containing-gas removing means for removing from received gas one or more gaseous species comprising nitrogen and oxygen which are either nitrogen dioxide, or formed from nitrogen dioxide in the presence of sufficient water vapor, which would otherwise lead to damage of the electrochemical oxygen sensor,

Abstract: An optical absorption gas sensor comprising a body having an internal wall which defines a chamber, at least one aperture in the body through which a gas sample can enter the chamber, a light source, at least one reflector, a detector assembly which extends into the chamber and has a first side and an opposite second side, a detector which measures light which is incident at at least a range of angles on at least a part of a first surface of the detector assembly on the first side of the detector assembly, wherein the light source is located within the chamber on the second side of the detector assembly, the whole being configured such that light from the light source passes through the gas sample and is reflected around the detector assembly, by the at least one reflector, onto the detector.