Global estimates of mortality associated with long-term exposure to outdoor fine particulate matter

Abstract

Exposure to ambient fine particulate matter (PM 2.5 ) is a major global health concern. Quantitative estimates of attributable mortality are based on disease-specific hazard ratio models that incorporate risk information from multiple PM 2.5 sources (outdoor and indoor air pollution from use of solid fuels and secondhand and active smoking), requiring assumptions about equivalent exposure and toxicity. We relax these contentious assumptions by constructing a PM 2.5 -mortality hazard ratio function based only on cohort studies of outdoor air pollution that covers the global exposure range. We modeled the shape of the association between PM 2.5 and nonaccidental mortality using data from 41 cohorts from 16 countries—the Global Exposure Mortality Model (GEMM). We then constructed GEMMs for five specific causes of death examined by the global burden of disease (GBD). The GEMM predicts 8.9 million [95% confidence interval (CI): 7.5–10.3] deaths in 2015, a figure 30% larger than that predicted by the sum of deaths among the five specific causes (6.9; 95% CI: 4.9–8.5) and 120% larger than the risk function used in the GBD (4.0; 95% CI: 3.3–4.8). Differences between the GEMM and GBD risk functions are larger for a 20% reduction in concentrations, with the GEMM predicting 220% higher excess deaths. These results suggest that PM 2.5 exposure may be related to additional causes of death than the five considered by the GBD and that incorporation of risk information from other, nonoutdoor, particle sources leads to underestimation of disease burden, especially at higher concentrations.

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Affiliated Institutions

• Public Health Ontario CA
• Fudan University CN
• ASL Roma IT
• Harvard University US
• Universität Ulm DE
• Health Canada CA
• University of California, Los Angeles US
• National Center for Chronic and Noncommunicable Disease Control and Prevention CN
• Institute for Health Metrics and Evaluation US
• Statistics Canada CA
• St George's, University of London GB
• Brigham Young University US
• University of New Brunswick CA
• University of Toronto CA
• Environmental Protection Agency US
• University of California, Davis US
• Azienda Sanitaria Locale Roma 3 IT
• University of British Columbia CA
• Zimmer Biomet (Germany) DE
• Cancer Prevention Institute of California US
• The University of Texas at Austin US
• Barcelona Institute for Global Health ES
• University of Minnesota US
• Utrecht University NL
• University of Hong Kong HK
• NYU Langone Health US
• American Cancer Society US
• Dalhousie University CA
• Carleton University CA
• McGill University CA
• New York University US
• University of Washington US
• University of Ottawa CA
• National Institute for Public Health and the Environment NL
• Health Effects Institute US

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