text: Observed median percentage decrease in PM2.5 (circle markers) for each country. Error bars indicate the 25th and 75th percentiles of the distribution. The color of the markers indicates the median stringency index based on all measurements associated with each country. Numbers in parentheses correspond to the number of publications and the number of data sets collected at each region/continent. Also, shown are the Emissions Database for Global Atmospheric Research inventory emission reductions calculated by Forster et al. (2020; star squares). DOI: https://doi.org/10.1525/elementa.2021.00176.f11