- European air quality index (based on pollutant concentrations in µg/m3): hourly measurements for all pollutants for the most recent hour for each station

- The sub-indices O3, PM10, PM2.5, NO2, and SO2 are available according to the type of station (industrial, background or traffic) in accordance with the methodology for calculating the European air quality index for the measuring stations throughout the Greater Region.

- Data depth: The most recent index for the last 3 hours for each station is available hourly. If the calculation of the index is not possible due to lack of data, its value is marked by a grey dot in the symbology of the map (data not available). In the absence of measurements of certain pollutants (missing sub-indices), the overall index is still calculated on the basis of the pollutants measured at the station concerned.

- Data sources: ATMO Grand Est; Agence Wallonne de l'Air et du Climat - AWAC; Landesamt für Umwelt- und Arbeitsschutz Saarland - IMMESA; Landesamt für Umwelt Rheinland-Pfalz - ZIMEN; Administration de l'environnement Luxembourg. Harmonization: ATMO Grand Est and GIS-GR 2020