Pandemic meets pollution: Poor air quality increases deaths by COVID-19

We study the impact of short-termexposure to ambient air pollution on the spread and severity of COVID-19 in Germany. We combine data at the county-by-day level on confirmed cases and deathswith information on local air quality andweather conditions. Following Deryugina et al. (2019), we instrument short-term variation in local concentrations of particulate matter (PM10) by region-specific daily variation in wind directions. We find significant positive effects of PM10 concentration on death numbers from four days before to ten days after the onset of symptoms. Specifically, for elderly patients (80+ years) an increase in ambient PM10 concentration by one standard deviation between two and four days after developing symptoms increases the number of deaths by 19 percent of a standard deviation. In addition, higher levels air pollution raise the number of confirmed cases of COVID-19 for all age groups. The timing of effects surrounding the onset of illness suggests that air pollution affects the severity of already-realized infections. We discuss the implications of our results for immediate policy levers to reduce the exposure and level of ambient air pollution, as well as for cost-benefit considerations of policies aiming at sustainable longer-termreductions of pollution levels. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

This study found significant impacts of air pollution on the spread and severity of COVID-19 in Germany, especially for elderly patients. High concentrations of PM10 led to increases in both death numbers and confirmed cases, with the timing of effects suggesting influence on the severity of realized infections. The results provide policy recommendations for immediate reduction of environmental pollution exposure and levels.