Air pollution and meteorology as risk factors for COVID-19 death in a cohort from Southern California

Michael Jerrett; Claudia L Nau; Deborah R Young; Rebecca K Butler; Christina M Batteate; Jason Su; Richard T Burnett; Michael J Kleeman

doi:10.1016/j.envint.2022.107675

Air pollution and meteorology as risk factors for COVID-19 death in a cohort from Southern California

Environ Int. 2023 Jan:171:107675. doi: 10.1016/j.envint.2022.107675. Epub 2022 Dec 2.

Authors

Michael Jerrett¹, Claudia L Nau², Deborah R Young², Rebecca K Butler², Christina M Batteate³, Jason Su⁴, Richard T Burnett⁵, Michael J Kleeman⁶

Affiliations

¹ Department of Environmental Health Sciences, University of California, Los Angeles 650 Charles Young Dr. S., 56-070 CHS Box 951772, Los Angeles, CA, 90095, United States. Electronic address: mjerrett@ucla.edu.
² Department of Research & Evaluation, Kaiser Permanente Southern California 100 S. Los Robles Ave., 5th Floor, Pasadena, CA 91101, United States.
³ Department of Environmental Health Sciences, University of California, Los Angeles 650 Charles Young Dr. S., 56-070 CHS Box 951772, Los Angeles, CA, 90095, United States.
⁴ Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley 2121 Berkeley Way, Room 5302, Berkeley, CA 94720, United States.
⁵ Population Studies Division, Environmental Health Directorate, Health Canada 251 Sir Frederick Banting Driveway, Ottawa, Ontario K1A 0K9, Canada.
⁶ Department of Civil and Environmental Engineering, University of California, Davis 1 Sheilds Avenue, Davis, CA 95616, United States.

Abstract

Background: Recent evidence links ambient air pollution to COVID-19 incidence, severity, and death, but few studies have analyzed individual-level mortality data with high quality exposure models.

Methods: We sought to assess whether higher air pollution exposures led to greater risk of death during or after hospitalization in confirmed COVID-19 cases among patients who were members of the Kaiser Permanente Southern California (KPSC) healthcare system (N=21,415 between 06-01-2020 and 01-31-2022 of whom 99.85 % were unvaccinated during the study period). We used 1 km resolution chemical transport models to estimate ambient concentrations of several common air pollutants, including ozone, nitrogen dioxide, and fine particle matter (PM_2.5). We also derived estimates of pollutant exposures from ultra-fine particulate matter (PM_0.1), PM chemical species, and PM sources. We employed Cox proportional hazards models to assess associations between air pollution exposures and death from COVID-19 among hospitalized patients.

Findings: We found significant associations between COVID-19 death and several air pollution exposures, including: PM_2.5 mass, PM_0.1 mass, PM_2.5 nitrates, PM_2.5 elemental carbon, PM_2.5 on-road diesel, and PM_2.5 on-road gasoline. Based on the interquartile (IQR) exposure increment, effect sizes ranged from hazard ratios (HR) = 1.12 for PM_2.5 mass and PM_2.5 nitrate to HR ∼ 1.06-1.07 for other species or source markers. Humidity and temperature in the month of diagnosis were also significant negative predictors of COVID-19 death and negative modifiers of the air pollution effects.

Interpretation: Air pollution exposures and meteorology were associated the risk of COVID-19 death in a cohort of patients from Southern California. These findings have implications for prevention of death from COVID-19 and for future pandemics.

Keywords: Air pollution; COVID-19; Cohort study; Death; Southern California.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants* / analysis
Air Pollution* / adverse effects
Air Pollution* / analysis
COVID-19*
California / epidemiology
Environmental Exposure / adverse effects
Humans
Meteorology
Nitrates
Particulate Matter / adverse effects
Particulate Matter / analysis
Risk Factors

Substances

Air Pollutants
Particulate Matter
Nitrates