Particulate matter air pollution and COVID-19 infection, severity, and mortality: A systematic review and meta-analysis

Nicola Sheppard; Matthew Carroll; Caroline Gao; Tyler Lane

doi:10.1016/j.scitotenv.2023.163272

Particulate matter air pollution and COVID-19 infection, severity, and mortality: A systematic review and meta-analysis

Sci Total Environ. 2023 Jul 1:880:163272. doi: 10.1016/j.scitotenv.2023.163272. Epub 2023 Apr 7.

Authors

Nicola Sheppard¹, Matthew Carroll², Caroline Gao³, Tyler Lane⁴

Affiliations

¹ Monash School of Medicine, Monash University, Clayton, Victoria, Australia.
² Monash Rural Health Churchill, Monash University, Churchill, VIC, Australia.
³ School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia; Orygen, Centre for Youth Mental Health, The University of Melbourne, Parkville, VIC, Australia.
⁴ School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia. Electronic address: tyler.lane@monash.edu.

Abstract

Ecological evidence links ambient particulate matter ≤2.5 mm (PM_2.5) and the rate of COVID-19 infections, severity, and deaths. However, such studies are unable to account for individual-level differences in major confounders like socioeconomic status and often rely on imprecise measures of PM_2.5. We conducted a systematic review of case-control and cohort studies, which rely on individual-level data, searching Medline, Embase, and the WHO COVID-19 database up to 30 June 2022. Study quality was evaluated using the Newcastle-Ottawa Scale. Results were pooled with a random effects meta-analysis, with Egger's regression, funnel plots, and leave-one-out/trim-and-fill sensitivity analyses to account for publication bias. N = 18 studies met inclusion criteria. A 10 μg/m³ increase in PM_2.5 was associated with 66 % (95 % CI: 1.31-2.11) greater odds of COVID-19 infection (N = 7) and 127 % (95 % CI: 1.41-3.66) odds of severe illness (hospitalisation, ICU admission, or requiring respiratory support) (N = 6). Pooled mortality results (N = 5) indicated increased deaths due to PM_2.5 but were non-significant (OR 1.40; 0.94 to 2.10). Most studies were rated "good" quality (14/18 studies), though there were numerous methodological issues; few used individual-level data to adjust for socioeconomic status (4/18 studies), instead using area-based indicators (11/18 studies) or no such adjustments (3/18 studies). Most severity (9/10 studies) and mortality studies (5/6 studies) were based on people already diagnosed COVID-19, potentially introducing collider bias. There was evidence of publication bias in studies of infection (p = 0.012) but not severity (p = 0.132) or mortality (p = 0.100). While methodological limits and evidence of bias require cautious interpretation of the findings, we found compelling evidence that PM_2.5 increases the risk of COVID-19 infection and severe disease, and weaker evidence of an increase in mortality risk.

Keywords: Coronavirus disease 2019; PM(2.5); SARS-CoV-2.

Publication types

Meta-Analysis
Systematic Review
Review

MeSH terms

Air Pollutants* / adverse effects
Air Pollutants* / analysis
Air Pollution* / adverse effects
Air Pollution* / analysis
COVID-19*
Cohort Studies
Environmental Exposure / analysis
Humans
Particulate Matter / adverse effects
Particulate Matter / analysis
Social Class

Substances

Particulate Matter
Air Pollutants