Air quality maps: Background information

How are the German Environment Agency's maps of Germany's current air pollution and ozone concentration forecasts drawn up? We explain here in brief.

Current Air pollution maps

The air quality maps are based on measurement data of around 400 stations of the German states and the German Environment Agency networks. The measured data reflect the air quality in the region of station's location. These point measurements are interpolated for a larger area to show the air pollutant distribution for the entire country. A radial basis function method (Hardy´s multiquadric interpolation scheme) plots the unevenly distributed measured values onto a structured grid. This grid is then displayed as a map. The individual grid cells have a resolution of 1.6 x 1.6 km2. This interpolation is implemented with the FLADIS program system for the analysis and visualisation of air quality data.

Measurements from "background stations" are used (not in the vicinity of significant air pollution sources) for the purposes of interpolation. "Traffic" and "Industry" stations are not taken into account in the interpolation due to their comparatively low representativeness of a larger geographic area. Measurements at these stations are shown as a circle on the map. 

Maps for the air pollutants particulate matter (PM10), sulphur dioxide, carbon monoxide, ozone and nitrogen dioxide are drawn up and can be viewed for every year starting 2016. Depending on the pollutant, filters can be selected for maps of its daily average, one hour average, maximum one hour average, eight hour average, and maximum eight hour average.

Ozone concentration forecast maps

For ozone, there are forecast maps for the current day and next two days available. The forecast maps can be accessed by selecting either the current or next two days in the "Date" filter. The forecast maps can be selected for a maximum one hour average and maximum eight hour average time scope. 

The forecast is calculated on the basis of the Copernicus Atmosphere Monitoring Service (CAMS) ensemble method. A hybrid correction method is applied to adjust the model forecast using measurements. The CAMS ensemble model forecast is based on the results of seven different chemical transport models for whole Europe. CAMS provides daily forecasts in hourly resolution on a grid with a horizontal resolution of roughly 10 km2. The results can be accessed here: https://atmosphere.copernicus.eu/.