Rationale: Risk factors for COVID-19 mortality may include environmental exposures, such as air pollution.Objectives: Determine whether, amongst adults hospitalized with PCR-confirmed COVID-19, long-term air pollution exposure is associated with risk for mortality, intensive care unit (ICU) admission or intubation.
Methods:We performed a retrospective analysis of SARS-CoV-2 PCR positive patients admitted to seven New York City hospitals from March 8, 2020 to August 30, 2020. The primary outcome was mortality; secondary outcomes were ICU admission and intubation. We estimated the annual average fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ) and black carbon (BC) concentrations at patients' residential addresses. We employed double-robust Poisson regression to analyze associations between annual average PM 2.5 , NO 2 and BC exposure and COVID-19 outcomes, adjusting for age, sex, race/ethnicity, hospital, insurance and time from onset of the pandemic.Results: Of the 6,542 patients, 41% were female and aged median 65 years (IQR 53, 77). Over 50% selfidentified as a person of color [N=1,687 (26%) Hispanic, N=1,659 (25%) Black]. Air pollution exposures were generally low. Overall, 31% (N=2,044) of the cohort died, 19% (N=1,237) were admitted to the ICU and 16% (1,051) were intubated. In multivariable models, higher long-term exposure to PM 2.5 was associated with increased risk of mortality (RR 1.11, 95% CI 1.02, 1.21 per 1µg/m 3 increase in PM 2.5 ) and ICU admission (RR 1.13, 95% CI 1.00, 1.28 per 1µg/m 3 increase in PM 2.5 ). In multivariable models, neither NO 2 nor BC exposure was associated with COVID-19 mortality, ICU admission or intubation.Conclusions: Amongst patients hospitalized with COVID-19, higher long-term PM 2.5 exposure was associated with increased risk of mortality and ICU admission.