Urban Air Pollution May Enhance COVID-19 Case-Fatality and Mortality Rates in the United States
Donghai Liang, Liuhua Shi, Jingxuan Zhao, P. Liu, Joel Schwartz, Song Gao, Jeremy A. Sarnat, Y. Liu, Stefanie Ebelt, Noah Scovronick, H. H. Chang
Abstract
Background: The novel human coronavirus disease 2019 (COVID-19) pandemic has claimed more than 240,000 lives worldwide, causing tremendous public health, social, and economic damages. While the risk factors of COVID-19 are still under investigation, environmental factors, such as urban air pollution, may play an important role in increasing population susceptibility to COVID-19 pathogenesis. Methods: We conducted a cross-sectional nationwide study using zero-inflated negative binomial models to estimate the association between long-term (2010-2016) county-level exposures to NO2, PM2.5 and O3 and county-level COVID-19 case-fatality and mortality rates in the US. We used both single and multipollutant models and controlled for spatial trends and a comprehensive set of potential confounders, including state-level test positive rate, county-level healthcare capacity, phase-of-epidemic, population mobility, sociodemographics, socioeconomic status, behavioral risk factors, and meteorology. Findings: 1,027,799 COVID-19 cases and 58,489 deaths were reported in 3,122 US counties from January 22 to April 29, 2020, with an overall observed case-fatality rate of 5·8%. County-level average NO2 concentrations were positively associated with both COVID-19 case-fatality and mortality rates in single-, bi-, and tri-pollutant models (p-values<0·05). Per inter-quartile range (IQR) increase in NO2 (4·6 ppb), COVID-19 case-fatality rate and mortality rate were associated with an increase of 7·1% (95% CI 1·2% to 13·4%) and 11·2% (95% CI 3·4% to 19·5%), respectively. We did not observe significant associations with long-term exposure to PM2.5 or O3. Interpretation: Long-term exposure to NO2, which largely arises from urban combustion sources such as traffic, may enhance susceptibility to severe COVID-19 outcomes, independent of long-term PM2.5 and O3 exposure. The results support targeted public health actions to protect residents from COVID-19 in heavily polluted regions with historically high NO2 levels. Continuation of current efforts to lower traffic emissions and ambient air pollution may be an important component of reducing population-level risk of COVID-19 case-fatality and mortality.