Monitoring European anthropogenic NOx emissions from space

Since the launch of TROPOMI on the S5p satellite, NO ₂ observations have become available with a resolution of 3.5x5 km, which makes monitoring NO _x emissions possible at the scale of city districts and industrial facilities. For Europe, emissions are reported on an annual basis for country totals and large industrial facilities and made publicly available via the European Environmental Agency (EEA). Satellite observations can provide independent and more timely information on NOx emissions. A new version of the inversion algorithm DECSO (Daily Emissions Constraint by Satellite Observations) has been developed for deriving NOx emissions for Europe on a daily basis, averaged to monthly mean maps. The estimated precision of these monthly emissions is about 25 % for individual grid cells. These satellite-derived emissions from DECSO have been compared to the officially reported European emissions and spatial-temporal disaggregated emission inventories. The country total DECSO NOx emissions are close to the reported emissions and the emissions compiled by the Copernicus Atmospheric Monitoring Service (CAMS). The comparison of the spatial distributed NOx emissions of DECSO and CAMS showed that the satellite-derived emissions are often higher in cities, while similar for large power plants and slightly lower in rural areas.