1. European Directive 2008/50/EC
: Ambient air quality and cleaner air for Europe, 2008
2. EN14211 Ambient air: Standard method for the measurement of the concentration of nitrogen dioxide and nitrogen monoxide by chemiluminescence, 2012
3. EN14212 Ambient air: Standard method for the measurement of the concentration of sulphur dioxide by ultraviolet fluorescence, 2012
4. EN 14625 Ambient air: Standard method for the measurement of the concentration of ozone by ultraviolet photometry, 2012
5. EN14626 Ambient air: Standard method for the measurement of the concentration of carbon monoxide by non-dispersive infrared spectroscopy, 2012