The findings show that 51,000 and 900 premature deaths could be prevented each year, respectively, if all the cities analysed were to achieve the PM2.5 and NO2 levels recommended by the World Health Organisation (WHO). If the cities were to match the air-quality levels of the least polluted city on the list, even more deaths could be prevented. Specifically, the number of premature deaths that could be prevented each year by reducing PM2.5 and NO2 concentrations to the lowest measured levels are 125,000 and 79,000, respectively.
“We observed great variability in the results for the different cities analysed,” said ISGlobal researcher Sasha Khomenko, lead author of the study. “The highest rates of mortality attributable to NO2, a toxic gas associated primarily with motor-vehicle traffic, were found in large cities in countries such as Spain, Belgium, Italy and France.” At the opposite end are cities in northern European countries with low rates of mortality attributable to air pollution.
Estimates for Swiss cities
The study also includes estimates for ten Swiss cities (Zurich, Geneva, Basel, Bern, Lausanne, Winterthur, St. Gallen, Lucerne, Lugano, Biel/Bienne), which represents about 16% of the Swiss population. Results show that if PM2.5 is reduced to WHO guidelines (10 ug/m3), 333 deaths could be prevented in total in these cities annually. If further reduced to the lowest level observed in any of the cities included in the study (=3.7 ug/m3), about 1000 cases could be prevented. “These results do not come as a surprise, they compare well to earlier burden of disease estimates done for Switzerland following similar methods,” said Kees de Hoogh, Scientific Project Leader at Swiss TPH and co-author of the study.
Urban and transport planning to improve people’s health
“Our findings support the evidence suggesting that there is no safe exposure threshold below which air pollution is harmless to health. They also suggest that the European legislation currently in force does not do enough to protect people’s health,” commented Mark Nieuwenhuijsen, Director of the Urban Planning, Environment and Health Initiative at ISGlobal and senior author of the study. “Therefore, the maximum NO2 and PM2.5 levels allowed by law should be revised. We hope that local authorities can use these data to implement urban and transport planning policies aimed at improving people’s health.”
Online Data Hub
This study forms part of the ISGlobal Ranking of Cities project and is the first in a series of analyses of the health impacts of various environmental factors inherent to urban life, including air pollution, noise, access to green spaces, heat island effects, etc. The website www.isglobalranking.org has been created as a hub for the rankings and detailed data on each city. The site is currently available in English, Spanish and Catalan. Data from the project’s other analyses and rankings will be added to the site as they become available.
About the Study
The study was led by ISGlobal in collaboration with Swiss TPH and Utrecht University. Swiss TPH researchers contributed by providing European wide air pollution exposure estimates and linking these to the study database.
Khomenko S, Cirach M, Pereira-Barboza E, Mueller N, Barrera-Gómez J, Rojas-Rueda D, de Hoogh K, Hoek G, Nieuwenhuijsen M. Premature mortality due to air pollution in European cities; an Urban Burden of Disease Assessment. The Lancet Planetary Health, 2021.