Spatiotemporal Variations and Trends in Tropospheric NO2 over Chongqing, a Mountainous Megacity in Southwest China, Based on Sentinel-5P TROPOMI Observations (2019–2024)
Nitrogen dioxide (NO2) drives ozone and secondary aerosol formation and harms human health. Chongqing, a mountainous megacity of 32 million people, lacks a fine-scale satellite assessment of its NO2 evolution. We analyzed tropospheric NO2 vertical column density (VCD) over Chongqing for 2019–2024. The analysis used Sen...