Exposure to air pollution and COVID-19 mortality in the United States

Xiao Wu; Rachel C. Nethery; Benjamin M. Sabath; Danielle Braun; Francesca Dominici

We fit zero-inflated negative binomial mixed models (ZNB). 22, 23, 24 using COVID-19 deaths as the outcome and PM 2.5 as the exposure of interest. The ZNB is composed of two sub-models. The first is a count sub-model that estimates the association between COVID-19 deaths and PM 2.5 (adjusted by covariates) among counties eligible (e.g., confirmed COVID-19 cases) to experience a COVID-19 death. The second is a zero sub-model that accounts for the excess of zeros that may be generated by counties not yet eligible for COVID-19 deaths (e.g., due to the absence of confirmed COVID-19 cases) and unlikely to have COVID-19 deaths as of April 4, 2020. Additional modeling details are provided in the Supplementary Materials. We include a population size offset and we adjust for all variables listed above. We also include a random intercept by state to account for potential correlation in counties within the same state, due to similar socio-cultural, behavioral, and healthcare system features and similar COVID-19 response and testing policies. We only report the result from the count sub-model. More All rights reserved. No reuse allowed without permission. author/funder, who has granted medRxiv a license to display the preprint in perpetuity.