This European Standard specifies requirements for the construction, testing and performance of electronic portable and transportable apparatus for the detection and measurement of carbon dioxide (CO2) and/or carbon monoxide (CO) in indoor ambient air, which includes air entering mechanical ventilation systems in domestic residential, commercial and industrial premises and public buildings. This European Standard includes indoor air quality apparatus with CO and CO2 measuring capabilities. This European Standard excludes: - apparatus used in workplace atmospheres for the direct detection and direct concentration measurement of toxic gases and vapours (i.e. conforming to EN 45544); - electronic portable combustion gas analysers (i.e. conforming to EN 50379). NOTE 1 Examples of applications are monitoring indoor air quality, measuring CO2 concentrations in commercial laundry and kitchen environments, assessing the safe operation of appliances installed in compartments. NOTE 2 When this apparatus is used in industrial premises national regulations may apply