Joint effect of heat and air pollution on mortality in 620 cities of 36 countries

• Authors: Massimo Stafoggi, Lazio Region Health Service; Paola Michelozzi, Lazio Region Health Service; Alexandra Schneider, German Research Center for Environmental Health; Ben Armstrong, London School of Hygiene and Tropical Medicine; Matteo Scortichini, Lazio Region Health Service; Masna Rai, German Research Center for Environmental Health; Souzana Achilleos, University of Nicosia; Barrak Alahmad, Harvard University; Antonis Analitis, National and Kapodistrian University of Athens; Christofer Åström, Umeå University; Michelle L. Bell, Yale University; Neville Calleja, Directorate for Health Information and Research; Hanne Krage Carlsen, University of Gothenburg; Gabriel Carrasco, Universidad Peruana Cayetano Heredia; John Paul Cauchi, Queen Mary University of London; Micheline DSZS Coelho, University of São Paulo; Patricia M. Correa, Universidad de los Andes; Magali H. Diaz, National Institute of Public Health, Cuernavaca; Alireza Entezari, Hakim Sabzevari University; Bertil Forsberg, Umeå University; Rebecca M. Garland, University of Pretoria; Yue Leon Guo, National Taiwan University; Yuming Guo, Monash University; Masahiro Hashizume, University of Tokyo; Iulian H. Holobaca, Babes-Bolay University; Carmen Íñiguez, Universitat de València; Jouni JK Jaakkola, University of Oulu; Haidong Kan, Fudan University; Klea Katsouyanni, national and Kapodistrian University of Athens; Ho Kim, Seoul National University; Jan Kyselý, Czech Academy of Sciences; Eric Lavigne, University of Ottawa; Whanhee Lee, Yale University; Shanshan Li, Monash University; Marek Maasikmets, Estonian Environmental Research Centre; Joana Madureira, Instituto Nacional de Saúde; Fatemeh Mayvaneh, Hakim Sabzevari University; Chris Fook Sheng Ng, University of Tokyo; Baltazar Nunes, Instituto Nacional de Saúde; Hans Orru, University of Tartu; Nicolás V. Ortega, Universidad de los Andes; Samuel Osorio, University of São Paulo; Alfonso DL Palomares, Norwegian Institute of Public Health; Shih-Chun Pan, National Health Research Institutes, Zhunan; Mathilde Pascal, French National Public Health Agency; Martina S. Ragettli, Swiss Tropical and Public Health Institute; Shilpa Rao, Norwegian Institute of Public Health; Raanan Raz, Hebrew University of Jerusalem; Dominic Roye, Climate Research Foundation, Madrid; Niilo Ryti, University of Oulu; Paulo HN Saldiva, University of São Paulo; Evangelia Samoli, National and Kapodistrian University of Athens; Joel Schwartz, Harvard University; Noah C Scovronick, Emory University; Francesco Sera, London School of Hygiene and Tropical Medicine; Aurelio Tobias, Institute of Environmental Assessment and Water Research; Shilu Tong, Queensland University of Technology; César DLC Valencia, National Institute of Public Health, Cuernavaca; Ana Maria Vicedo-Cabrera, University of Bern; Aleš Urban, Czech Academy of Sciences; Antonio Gasparrini, London School of Hygiene and Tropical Medicine; Susanne Breitner, LMU Munich; Francesca K. de' Donato, Lazio Region Health Service
• Journal Title: Environment International
• Volume: Volume 181
• Publisher: Elsevier | 2023-10-10, Pages 108258-None
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.envint.2023.108258
• Subjects: Health Sciences, Epidemiology; Environmental Sciences; Health Sciences, Public Health
• Keywords: Air temperature; Air pollution; Effect modification; Epidemiology; Mortality

Abstract

Background: The epidemiological evidence on the interaction between heat and ambient air pollution on mortality is still inconsistent. Objectives: To investigate the interaction between heat and ambient air pollution on daily mortality in a large dataset of 620 cities from 36 countries. Methods: We used daily data on all-cause mortality, air temperature, particulate matter ≤ 10 μm (PM10), PM ≤ 2.5 μm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) from 620 cities in 36 countries in the period 1995–2020. We restricted the analysis to the six consecutive warmest months in each city. City-specific data were analysed with over-dispersed Poisson regression models, followed by a multilevel random-effects meta-analysis. The joint association between air temperature and air pollutants was modelled with product terms between non-linear functions for air temperature and linear functions for air pollutants. Results: We analyzed 22,630,598 deaths. An increase in mean temperature from the 75th to the 99th percentile of city-specific distributions was associated with an average 8.9 % (95 % confidence interval: 7.1 %, 10.7 %) mortality increment, ranging between 5.3 % (3.8 %, 6.9 %) and 12.8 % (8.7 %, 17.0 %), when daily PM10 was equal to 10 or 90 μg/m3, respectively. Corresponding estimates when daily O3 concentrations were 40 or 160 μg/m3 were 2.9 % (1.1 %, 4.7 %) and 12.5 % (6.9 %, 18.5 %), respectively. Similarly, a 10 μg/m3 increment in PM10 was associated with a 0.54 % (0.10 %, 0.98 %) and 1.21 % (0.69 %, 1.72 %) increase in mortality when daily air temperature was set to the 1st and 99th city-specific percentiles, respectively. Corresponding mortality estimate for O3 across these temperature percentiles were 0.00 % (−0.44 %, 0.44 %) and 0.53 % (0.38 %, 0.68 %). Similar effect modification results, although slightly weaker, were found for PM2.5 and NO2. Conclusions: Suggestive evidence of effect modification between air temperature and air pollutants on mortality during the warm period was found in a global dataset of 620 cities.