Table 1.
Predicted and observed (OMI and TROPOMI) changes of tropospheric NO2 vertical column densities (TropNO2VCDs) during 2019–2020 LNY holiday seasons over major metropolitan areas and corresponding percentage of tropospheric NO2 reductions caused by the clean air regulations based on TROPOMI and OMI.
| Predicted 19–20 Changes (DU) | 19–20 Changes by TROPOMI (DU) | 19–20 Changes by OMI (DU) | Percentage of tropospheric NO2 reduction caused by clean air regulations based on TROPOMI (%) | Percentage of tropospheric NO2 reduction caused by clean air regulations based on OMI (%) | |
|---|---|---|---|---|---|
| Beijing | −0.022 | −0.068 | −0.195 | 32 | 11 |
| PRD | −0.049 | −0.087 | −0.078 | 56 | 63 |
| Sichuan | −0.017 | −0.045 | −0.045 | 38 | 38 |
| Wuhan | −0.027 | −0.211 | −0.28 | 13 | 10 |
| YRD | −0.041 | −0.179 | −0.263 | 23 | 16 |