Does air pollution modify temperature-related mortality? A systematic review and meta-analysis

Xin Hu; Wenxing Han; Yuxin Wang; Kristin Aunan; Xiaochuan Pan; Jing Huang; Guoxing Li

doi:10.1016/j.envres.2022.112898

Does air pollution modify temperature-related mortality? A systematic review and meta-analysis

Environ Res. 2022 Jul:210:112898. doi: 10.1016/j.envres.2022.112898. Epub 2022 Feb 16.

Authors

Xin Hu¹, Wenxing Han¹, Yuxin Wang¹, Kristin Aunan², Xiaochuan Pan¹, Jing Huang¹, Guoxing Li³

Affiliations

¹ Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, 38 Xueyuan Road, Haidian District, Beijing, 100191, China.
² CICERO Center for International Climate Research, N-0318, Oslo, Norway.
³ Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, 38 Xueyuan Road, Haidian District, Beijing, 100191, China. Electronic address: liguoxing@bjmu.edu.cn.

PMID: 35181304
DOI: 10.1016/j.envres.2022.112898

Abstract

Introduction: There is an increasing interest in understanding whether air pollutants modify the quantitative relationships between temperature and health outcomes. The results of available studies were, however, inconsistent. This study aims to sum up the current evidence and provide a comprehensive understanding of this topic.

Methods: We conducted an electronic search in PubMed (MEDLINE), EMBASE, Web of Science Core Collection, and ProQuest Dissertations and Theses. The modified Navigation Guide was applied to evaluate the quality and strength of evidence. We calculated pooled temperature-related mortality at low and high pollutant levels respectively, using the random-effects model.

Results: We identified 22 eligible studies, eleven of which were included in the meta-analysis. Significant effect modification was observed on heat effects for all-cause and non-accidental mortality by particulate matter with an aerodynamic diameter of <10 μm (PM₁₀) and ozone (O₃) (p < 0.05). The excess risks (ERs) for all-cause and non-accidental mortality were 5.4% (4.4%, 6.4%) and 6.3% (4.8%, 7.8%) at the low PM₁₀ level, 8.8% (7.5%, 10.1%) and 11.4% (8.7%, 14.2%) at the high PM₁₀ level, respectively. As for O₃, the ERs for all-cause and non-accidental mortality were 5.1% (3.9%, 6.3%) and 3.6% (0.1%, 7.2%) at the low O₃ level, 7.6% (6.3%, 9.0%) and 12.5% (4.7%, 20.9%) at the high O₃ level, respectively. Surprisingly, the heat effects on cardiovascular mortality were found to be lower at high carbon monoxide (CO) levels [ERs = 5.4% (3.9%, 6.9%)] than that at low levels [ERs = 9.4% (7.0%, 11.9%)]. The heterogeneity varied, but the results of sensitivity analyses were generally robust. Significant effect modification by air pollutants was not observed for heatwave or cold effects.

Conclusions: PM₁₀ and O₃ modify the heat-related all-cause and non-accidental mortality, indicating that policymakers should consider air pollutants when establishing heat-health warning systems. Future studies with comparable designs and settings are needed.

Keywords: Air pollution; Extreme temperature; Meta-analysis; Modification; Mortality; Navigation guide.

Publication types

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

MeSH terms

Air Pollutants* / analysis
Air Pollutants* / toxicity
Air Pollution* / adverse effects
Air Pollution* / analysis
Environmental Exposure / analysis
Nitrogen Dioxide / analysis
Ozone* / analysis
Particulate Matter / analysis
Temperature

Substances

Air Pollutants
Particulate Matter
Ozone
Nitrogen Dioxide