We present an updated (v2) catalog of NOx emissions from point sources as derived from TROPOMI measurements
of NO2 (PAL product, May 2018 - Nov 2021) combined with wind fields from ERA5. Compared to version 1 of the catalog,
several improvements have been introduced to the algorithm. Most importantly, several corrections are applied, accounting
for the effects of plume height on satellite sensitivity, 3D topographic effects, and the chemical loss of NOx , resulting in
considerably higher and more accurate NOx emissions. In addition, error estimates are provided for each point source, taking
into account the uncertainties of the individual retrieval steps.
The catalog v2 is based on a fully automated iterative detection algorithm of point sources worldwide. It lists 1139 locations
that have been found to be significant NOx sources. The majority of these locations match to power plants listed in the global
power plant database. Other NOx point sources correspond to cement plants, metal smelters, industrial areas, or medium-sized
cities.