Effects of COVID-19 lockdowns on fine particulate matter concentrations





Citation of Original Publication

Hammer, Melanie S., Aaron van Donkelaar, Randall V. Martin, Erin E. McDuffie, Alexei Lyapustin, Andrew M. Sayer, N. Christina Hsu, et al. “Effects of COVID-19 Lockdowns on Fine Particulate Matter Concentrations.” Science Advances 7, no. 26 (June 23, 2021): eabg7670. https://doi.org/10.1126/sciadv.abg7670.


This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
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Lockdowns during the COVID-19 pandemic provide an unprecedented opportunity to examine the effects of human activity on air quality. The effects on fine particulate matter (PM₂.₅) are of particular interest, as PM₂.₅ is the leading environmental risk factor for mortality globally. We map global PM₂.₅ concentrations for January to April 2020 with a focus on China, Europe, and North America using a combination of satellite data, simulation, and ground-based observations. We examine PM₂.₅ concentrations during lockdown periods in 2020 compared to the same periods in 2018 to 2019. We find changes in population-weighted mean PM₂.₅ concentrations during the lockdowns of −11 to −15 μg/m³ across China, +1 to −2 μg/m³ across Europe, and 0 to −2 μg/m³ across North America. We explain these changes through a combination of meteorology and emission reductions, mostly due to transportation. This work demonstrates regional differences in the sensitivity of PM₂.₅ to emission sources.