BACKGROUND The systematic evaluation of the results of time-series studies of air pollution is challenged by differences in model specification and publication bias. METHODS We evaluated the associations of inhalable particulate matter (PM) with an aerodynamic diameter of 10 μm or less (PM10) and fine PM with an aerodynamic diameter of 2.5 μm or less (PM2.5) with daily all-cause, cardiovascular, and respiratory mortality across multiple countries or regions. Daily data on mortality and air pollution were collected from 652 cities in 24 countries or regions. We used overdispersed generalized additive models with random-effects meta-analysis to investigate the associations. Two-pollutant models were fitted to test the robustness of the associations. Concentration–response curves from each city were pooled to allow global estimates to be derived. RESULTS On average, an increase of 10 μg per cubic meter in the 2-day moving average of PM10 concentration, which represents the average over the current and previous day, was associated with increases of 0.44% (95% confidence interval [CI], 0.39 to 0.50) in daily all-cause mortality, 0.36% (95% CI, 0.30 to 0.43) in daily cardiovascular mortality, and 0.47% (95% CI, 0.35 to 0.58) in daily respiratory mortality. The corresponding increases in daily mortality for the same change in PM2.5 concentration were 0.68% (95% CI, 0.59 to 0.77), 0.55% (95% CI, 0.45 to 0.66), and 0.74% (95% CI, 0.53 to 0.95). These associations remained significant after adjustment for gaseous pollutants. Associations were stronger in locations with lower annual mean PM concentrations and higher annual mean temperatures. The pooled concentration–response curves showed a consistent increase in daily mortality with increasing PM concentration, with steeper slopes at lower PM concentrations. CONCLUSIONS Our data show independent associations between short-term exposure to PM10 and PM2.5 and daily all-cause, cardiovascular, and respiratory mortality in more than 600 cities across the globe. These data reinforce the evidence of a link between mortality and PM concentration established in regional and local studies. (Funded by the National Natural Science Foundation of China and others.)
Bibliographical noteFunding Information:
lic Health, Cuernavaca, Mexico (M.H.-D., J. Cruz); the Department of Epidemiology, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisbon (B.N., J.P.T.), and the Epidemiology Research Unit–Instituto de Saúde Pública, Universidade do Porto, Porto (J.P.T.) — both in Portugal; the Department of Public Health Science, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul, South Korea (H. Kim); the Institute of Environmental Assessment and Water Research, Spanish Council for Scientific Research, Barcelona (A.T.), and the Department of Statistics and Computational Research, University of Valencia Environmental Health Joint Research Unit Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana–Universitat de València–Universitat Jaume I de Castellón Biomedical Research Center Network for Epidemiology and Public Health, Valencia (C.I.) — both in Spain; the Swiss Tropical and Public Health Institute and the University of Basel, Basel, Switzerland (M.S.R.); Environmental and Occupational Medicine, National Taiwan University (Y.-L.G., B.-Y.C.), and the College of Medicine and National Taiwan University Hospital (Y.-L.G.), Taipei City; the School of Forestry and Environmental Studies, Yale University, New Haven, CT (M.L.B.); the Environment and Health Research Unit, South African Medical Research Council (C.Y.W.), the Department of Geography, Geo-informatics, and Meteorology, University of Pretoria (C.Y.W., R.M.G.), and the Natural Resources and the Environment Unit, Council for Scientific and Industrial Research (R.M.G.), Pretoria, and the Unit for Environmental Sciences and Management, North-West University, Potchef-stroom (R.M.G.) — all in South Africa; the Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta (N.S.); the Institute of Atmospheric Physics, Czech Academy of Sciences, (J.K., A.U.), and the Faculty of Environmental Sciences (J.K.), Czech University of Life Sciences, Prague, Czech Republic; the Institute of Family Medicine and Public Health, University of Tartu, Tartu, Estonia (H.O., E.I.); the Center for Environmental and Respiratory Health Research, University of Oulu, Medical Research Center Oulu, and Oulu University Hospital and University of Oulu, Oulu, Finland (J.J.K.J., N.R.I.R.); the Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, Athens (K.K., A.A.); the Department of Environmental Health, Harvard T.H. Chan School of Public Health (A.Z., J.S.), and the Health Effects Institute (A.C.), Boston; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (A.C.).
Supported by the National Natural Science Foundation of China (grants 91843302 and 91643205, to Dr. Kan); the China Medical Board Collaborating Program (grant 16-250); the Medical Research Council, United Kingdom (grants MR/R013349/1 and MR/M022625/1, to Drs. Gasparrini, Sera, and Vicedo-Cabrera); the Career Development Fellowship of the Australian National Health and Medical Research Council (grants APP1107107 and APP1163693, to Dr. Guo); the Ministry of Education of Spain (grant PRX17/00705, to Dr. Tobias); the National Plan for I+D+I (grant PI15/00515), cofunded by the Instituto de Salud Carlos III Directorate General for Evaluation and the European Regional Development Fund (FEDER); the Global Research Laboratory (grant K21004000001-10A0500-00710 from the National Research Foundation of Korea, funded by the Ministry of Science, Information and Communication Technologies, to Dr. Kim); the Academy of Finland (grants 310372 and 310373, to Drs. Jaakkola and Ryti); the Estonian Ministry of Education and Research (grant IUT34-17, to Drs. Orru and Indermitte); the Czech Science Foundation (grant 18-22125S, to Drs. Kyselý and Urban); and a Professional Services Agreement with the Health Effects Institute, United States (to Dr. Cohen).
Our data show independent associations between short-term exposure to PM10 and PM2.5 and daily all-cause, cardiovascular, and respiratory mortality in more than 600 cities across the globe. These data reinforce the evidence of a link between mortality and PM concentration established in regional and local studies. (Funded by the National Natural Science Foundation of China and others.)
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