Urban population exposure to air pollution in Europe over the last decades.

Background: The paper presents an overview of air quality in the 27 member countries of the European Union (EU) and the United Kingdom (previous EU-28), from 2000 to 2017. We reviewed the progress made towards meeting the air quality standards established by the EU Ambient Air Quality Directives (European Council Directive 2008/50/EC) and the World Health Organization (WHO) Air Quality Guidelines by estimating the trends (Mann-Kendal test) in national emissions of main air pollutants, urban population exposure to air pollution, and in mortality related to exposure to ambient fine particles (PM_2.5) and tropospheric ozone (O₃). Results: Despite significant reductions of emissions (e.g., sulfur oxides: ~ 80%, nitrogen oxides: ~ 46%, non-methane volatile organic compounds: ~ 44%, particulate matters with a diameter lower than 2.5 µm and 10 µm: ~ 30%), the EU-28 urban population was exposed to PM_2.5 and O₃ levels widely exceeding the WHO limit values for the protection of human health. Between 2000 and 2017, the annual PM_2.5-related number of deaths decreased (- 4.85 per 10⁶ inhabitants) in line with a reduction of PM_2.5 levels observed at urban air quality monitoring stations. The rising O₃ levels became a major public health issue in the EU-28 cities where the annual O₃-related number of premature deaths increased (+ 0.55 deaths per 10⁶ inhabitants). Conclusions: To achieve the objectives of the Ambient Air Quality Directives and mitigate air pollution impacts, actions need to be urgently taken at all governance levels. In this context, greening and re‐naturing cities and the implementation of fresh air corridors can help meet air quality standards, but also answer to social needs, as recently highlighted by the COVID-19 lockdowns. [ABSTRACT FROM AUTHOR]