Exposure to air pollution and COVID 19 mortality in the United States
Background: United States government scientists estimate that COVID 19 may kill between 100,000 and 240,000 Americans. The majority of the pre existing conditions that increase the risk of death for COVID 19 are the same diseases that are affected by long term exposure to air pollution. We investigate whether long term average exposure to fine particulate matter (PM2.5) increases the risk of COVID 19 deaths in the United States. Methods: Data was collected for approximately 3,000 counties in the United States (98% of the population) up to April 04, 2020. We fit zero inflated negative binomial mixed models using county level COVID 19 deaths as the outcome and county level long term average of PM2.5 as the exposure. We adjust by population size, hospital beds, number of individuals tested, weather, and socioeconomic and behavioral variables including, but not limited to obesity and smoking. We include a random intercept by state to account for potential correlation in counties within the same state. Results: We found that an increase of only 1 g/m in PM2.5 is associated with a 15% increase in the COVID 19 death rate, 95% confidence interval (CI) (5% 25% Results are statistically significant and robust to secondary and sensitivity analyses. Conclusions: A small increase in long term exposure to PM2.5 leads to a large increase in COVID 19 death rate, with the magnitude of increase 20 times that observed for PM2.5 and allcause mortality. The study results underscore the importance of continuing to enforce existing air pollution regulations to protect human health both during and after the COVID 19 crisis. The data and code are publicly available. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 7, 2020. https:/doi.org/10.1101/2020.04.05.20054502 doi: medRxiv preprint