Air quality indices in the municipality over 3 days

** Decree of 10/07/20 on the ambient air quality index (OJ No 185 of 29 July 2020)** The Ambient Air Quality Index is a communication tool that makes it possible to provide synthetic information in a simple form (6 colours accompanied by a qualifier) on the level of ambient air pollution, by aggregating data of measured or modeled concentrations of several air pollutants within a public inter-municipal cooperation institution. This index is calculated for one day and for a representative geographical area. All the areas cover the territory of the municipalities of the Centre-Val de Loire region. This index shall be calculated in accordance with the provisions of Article 3 of the Decree of 10 July 2020. It is the aggregate result of the monitoring of five air pollutants: sulphur dioxide ‘SO2’, nitrogen dioxide ‘NO2’, ozone ‘O3’, particles with aerodynamic diameter less than 10 micrometres ‘PM10’ and particles with aerodynamic diameter less than 2.5 micrometres ‘PM2.5’. The measurement or modelling of ambient air concentrations representative of a background situation for pollutants used in the calculation of sub-indexes shall be carried out in accordance with the provisions laid down in the above-mentioned amended Decree of 19 April 2017. The index characterising the overall air quality of the day in question is equal to the most degraded sub-index.