Fig. 6: Comparisons between tropospheric NO2 VCDs from EMI and TROPOMI.

a Shows the daily mean time series of tropospheric NO2 VCD over the North China Plain (NCP) from EMI and TROPOMI. Error bars indicate the 1σ standard deviation. b The density scatter plot of NO2 VCDs over the NCP. Data are regridded to a resolution of 0.2° and averaged for the period of January–August 2019