Effects of long-term exposure to outdoor air pollution on COVID-19 incidence: A population-based cohort study accounting for SARS-CoV-2 exposure levels in the Netherlands

Jelle Zorn; Mariana Simões; Guus J M Velders; Miriam Gerlofs-Nijland; Maciek Strak; José Jacobs; Marieke B A Dijkema; Thomas J Hagenaars; Lidwien A M Smit; Roel Vermeulen; Lapo Mughini-Gras; Lenny Hogerwerf; Don Klinkenberg

doi:10.1016/j.envres.2024.118812

Effects of long-term exposure to outdoor air pollution on COVID-19 incidence: A population-based cohort study accounting for SARS-CoV-2 exposure levels in the Netherlands

Environ Res. 2024 Mar 30;252(Pt 1):118812. doi: 10.1016/j.envres.2024.118812. Online ahead of print.

Affiliations

¹ National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
² Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
³ National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Institute for Marine and Atmospheric Research (IMAU), Utrecht University, Utrecht, the Netherlands.
⁴ Environment and Health in Overijssel and Gelderland, Public Health Services Gelderland-Midden, the Netherlands.
⁵ Wageningen Bioveterinary Research, Lelystad, the Netherlands.
⁶ National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands. Electronic address: lapo.mughini.gras@rivm.nl.

PMID: 38561121
DOI: 10.1016/j.envres.2024.118812

Abstract

Several studies have linked air pollution to COVID-19 morbidity and severity. However, these studies do not account for exposure levels to SARS-CoV-2, nor for different sources of air pollution. We analyzed individual-level data for 8.3 million adults in the Netherlands to assess associations between long-term exposure to ambient air pollution and SARS-CoV-2 infection (i.e., positive test) and COVID-19 hospitalisation risks, accounting for spatiotemporal variation in SARS-CoV-2 exposure levels during the first two major epidemic waves (February 2020-February 2021). We estimated average annual concentrations of PM₁₀, PM_2.5 and NO₂ at residential addresses, overall and by PM source (road traffic, industry, livestock, other agricultural sources, foreign sources, other Dutch sources), at 1 × 1 km resolution, and weekly SARS-CoV-2 exposure at municipal level. Using generalized additive models, we performed interval-censored survival analyses to assess associations between individuals' average exposure to PM₁₀, PM_2.5 and NO₂ in the three years before the pandemic (2017-2019) and COVID-19-outcomes, adjusting for SARS-CoV-2 exposure, individual and area-specific confounders. In single-pollutant models, per interquartile (IQR) increase in exposure, PM₁₀ was associated with 7% increased infection risk and 16% increased hospitalisation risk, PM_2.5 with 8% increased infection risk and 18% increased hospitalisation risk, and NO₂ with 3% increased infection risk and 11% increased hospitalisation risk. Bi-pollutant models suggested that effects were mainly driven by PM. Associations for PM were confirmed when stratifying by urbanization degree, epidemic wave and testing policy. All emission sources of PM, except industry, showed adverse effects on both outcomes. Livestock showed the most detrimental effects per unit exposure, whereas road traffic affected severity (hospitalisation) more than infection risk. This study shows that long-term exposure to air pollution increases both SARS-CoV-2 infection and COVID-19 hospitalisation risks, even after controlling for SARS-CoV-2 exposure levels, and that PM may have differential effects on these COVID-19 outcomes depending on the emission source.

Keywords: COVID-19; Force of infection; NO2; PM10; PM2.5; SARS-CoV-2.