Ambient air pollution and COVID-19 risk: Evidence from 35 observational studies

Si-Tian Zang; Jie Luan; Ling Li; Hui-Xin Yu; Qi-Jun Wu; Qing Chang; Yu-Hong Zhao

doi:10.1016/j.envres.2021.112065

Ambient air pollution and COVID-19 risk: Evidence from 35 observational studies

Environ Res. 2022 Mar;204(Pt B):112065. doi: 10.1016/j.envres.2021.112065. Epub 2021 Sep 15.

Authors

Si-Tian Zang¹, Jie Luan², Ling Li³, Hui-Xin Yu⁴, Qi-Jun Wu⁵, Qing Chang⁶, Yu-Hong Zhao⁷

Affiliations

¹ Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, Liaoning, 110004, China; Clinical Research Center, Shengjing Hospital of China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, Liaoning, 110022, China. Electronic address: stzang@cmu.edu.cn.
² Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, Liaoning, 110004, China; Clinical Research Center, Shengjing Hospital of China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, Liaoning, 110022, China. Electronic address: jluan@cmu.edu.cn.
³ Center for Precision Medicine Research and Training, University of Macau, Avenida da Universidade Taipa, Macau, 999078, China. Electronic address: yc07610@connect.um.edu.mo.
⁴ Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, Liaoning, 110004, China; Clinical Research Center, Shengjing Hospital of China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, Liaoning, 110022, China. Electronic address: hxyu@cmu.edu.cn.
⁵ Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, Liaoning, 110004, China; Clinical Research Center, Shengjing Hospital of China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, Liaoning, 110022, China. Electronic address: wuqj@sj-hospital.org.
⁶ Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, Liaoning, 110004, China; Clinical Research Center, Shengjing Hospital of China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, Liaoning, 110022, China. Electronic address: changq@sj-hospital.org.
⁷ Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, Liaoning, 110004, China. Electronic address: zhaoyuhong@sj-hospital.org.

Abstract

Background and aims: The coronavirus disease 2019 (COVID-19) pandemic is severely threatening and challenging public health worldwide. Epidemiological studies focused on the influence of outdoor air pollution (AP) on COVID-19 risk have produced inconsistent conclusions. We aimed to quantitatively explore this association using a meta-analysis.

Methods: We searched for studies related to outdoor AP and COVID-19 risk in the Embase, PubMed, and Web of Science databases. No language restriction was utilized. The search date entries were up to August 13, 2021. Pooled estimates and 95% confidence intervals (CIs) were obtained with random-/fixed-effects models. PROSPERO registration number: CRD42021244656.

Results: A total of 35 articles were eligible for the meta-analysis. For long-term exposure to AP, COVID-19 incidence was positively associated with 1 μg/m³ increase in nitrogen dioxide (NO₂; effect size = 1.042, 95% CI 1.017-1.068), particulate matter with diameter <2.5 μm (PM_2.5; effect size = 1.056, 95% CI 1.039-1.072), and sulfur dioxide (SO₂; effect size = 1.071, 95% CI 1.002-1.145). The COVID-19 mortality was positively associated with 1 μg/m³ increase in nitrogen dioxide (NO₂; effect size = 1.034, 95% CI 1.006-1.063), PM_2.5 (effect size = 1.047, 95% CI 1.025-1.1071). For short-term exposure to air pollutants, COVID-19 incidence was positively associated with 1 unit increase in air quality index (effect size = 1.001, 95% CI 1.001-1.002), 1 μg/m³ increase NO₂ (effect size = 1.014, 95% CI 1.011-1.016), particulate matter with diameter <10 μm (PM₁₀; effect size = 1.005, 95% CI 1.003-1.008), PM_2.5 (effect size = 1.003, 95% CI 1.002-1.004), and SO₂ (effect size = 1.015, 95% CI 1.007-1.023).

Conclusions: Outdoor air pollutants are detrimental factors to COVID-19 outcomes. Measurements beneficial to reducing pollutant levels might also reduce the burden of the pandemic.

Keywords: Air pollution; COVID-19 incidence; COVID-19 mortality; Meta-analysis; Observational study.

Publication types

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

MeSH terms

Air Pollution* / adverse effects
COVID-19*
Environmental Exposure / analysis
Humans
Particulate Matter / toxicity
SARS-CoV-2

Substances

Particulate Matter