Environment International (Nov 2023)

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

  • Massimo Stafoggia,
  • Paola Michelozzi,
  • Alexandra Schneider,
  • Ben Armstrong,
  • Matteo Scortichini,
  • Masna Rai,
  • Souzana Achilleos,
  • Barrak Alahmad,
  • Antonis Analitis,
  • Christofer Åström,
  • Michelle L. Bell,
  • Neville Calleja,
  • Hanne Krage Carlsen,
  • Gabriel Carrasco,
  • John Paul Cauchi,
  • Micheline DSZS Coelho,
  • Patricia M. Correa,
  • Magali H. Diaz,
  • Alireza Entezari,
  • Bertil Forsberg,
  • Rebecca M. Garland,
  • Yue Leon Guo,
  • Yuming Guo,
  • Masahiro Hashizume,
  • Iulian H. Holobaca,
  • Carmen Íñiguez,
  • Jouni J.K. Jaakkola,
  • Haidong Kan,
  • Klea Katsouyanni,
  • Ho Kim,
  • Jan Kyselý,
  • Eric Lavigne,
  • Whanhee Lee,
  • Shanshan Li,
  • Marek Maasikmets,
  • Joana Madureira,
  • Fatemeh Mayvaneh,
  • Chris Fook Sheng Ng,
  • Baltazar Nunes,
  • Hans Orru,
  • Nicolás V Ortega,
  • Samuel Osorio,
  • Alfonso D.L. Palomares,
  • Shih-Chun Pan,
  • Mathilde Pascal,
  • Martina S Ragettli,
  • Shilpa Rao,
  • Raanan Raz,
  • Dominic Roye,
  • Niilo Ryti,
  • Paulo HN Saldiva,
  • Evangelia Samoli,
  • Joel Schwartz,
  • Noah Scovronick,
  • Francesco Sera,
  • Aurelio Tobias,
  • Shilu Tong,
  • César DLC Valencia,
  • Ana Maria Vicedo-Cabrera,
  • Aleš Urban,
  • Antonio Gasparrini,
  • Susanne Breitner,
  • Francesca K. de' Donato

Journal volume & issue
Vol. 181
p. 108258

Abstract

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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.

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