Quantitative assessment of changes in surface particulate matter concentrations and precursor emissions over China during the COVID-19 pandemic and their implications for Chinese economic activity - Kim, H. C.; Kim, S.; Cohen, M.; Bae, C.; Lee, D.; Saylor, R.; Bae, M.; Kim, E.; Kim, B.-U.; Yoon, J.-H.; Stein, A. (Atmos. Chem. Phys., 2021)