Fig. 7: Nitrogen dioxide (NO2) column density in the troposphere.

a Climatology (2019–2023) and b differences (2020–2023 mean minus 2019) of NO2 column density (kg m−2) in the troposphere. Circles in panel b indicate grid cells with statistically significant differences at 95% confidence level. Data are from TROPOMI. The figure was created using Matplotlib Python package.