Observed and simulated PM2.5 data used to study COVID-19 lockdowns' impacts on urban PM2.5 air quality

This data set includes: (1) the 5-day running mean PM2.5 concentrations in individual years for 22 stations. These data were used in an analysis published in Atmospheric Chemistry and Physics (Yu et al., Assessing COVID-19 lockdowns’ impacts on global urban PM2.5 air quality with observations and modeling, 2025). Original data were obtained from several sources, which is described in the paper. (2) Observed and GEOS-simulated March-April average PM2.5 difference (ug/m3) between 2020 and 2019 (used to generate Figures 10, 15, and S10). (3) Observed and GEOS-simulated March-April average PM2.5 and AOD differences (ug/m3 or %) between 2020 and 2019 (used to generate Figures 13 and 14).