Abstract: A method of measuring a radon concentration or a radon exposure level comprising: placing a plurality of individual radon measurement instruments at locations, each instrument being capable of data output; receiving radon measurement data from each of said plurality of instruments; combining said data from said plurality of instruments into a single data set; and calculating a radon concentration or radon exposure value from said single data set. Using a plurality of individual detectors and combining their data provides a much better overall analysis of radon concentration or radon exposure level. The calculated value may include producing an average of the radon concentrations across the multiple instruments. The average may be weighted with weights determined according to different locations such as proximity to ventilation devices or based on the time that an average user spends in each location.

Abstract: A gas sensor instrument comprises a housing formed of two parts (102, 10) and a diffusion chamber inside the housing. The diffusion chamber is formed from two parts (106, 108) and at least one of the diffusion chamber parts is formed integrally with one of the housing parts. This allows a reduction in size of the instrument without compromising the size of the diffusion chamber. Additionally, a tubular projection is formed integrally with one of the housing parts to form part of a Faraday cage for shielding an amplifier circuit of the instrument.

Abstract: A method of measuring a radon concentration or a radon exposure level comprising: placing a plurality of individual radon measurement instruments at locations, each instrument being capable of data output; receiving radon measurement data from each of said plurality of instruments; combining said data from said plurality of instruments into a single data set; and calculating a radon concentration or radon exposure value from said single data set. Using a plurality of individual detectors and combining their data provides a much better overall analysis of radon concentration or radon exposure level. The calculated value may include producing an average of the radon concentrations across the multiple instruments. The average may be weighted with weights determined according to e.g. different locations such as proximity to ventilation devices or based on the time that an average user spends in each location.