Introduction - Continuous improvements in air quality in Île-de-France have saved many lives. However, the impact observed even today remains substantial. For over thirty years, the Île-de-France Regional Health Observatory (ORS) has supported air quality improvement policies by conducting quantitative health impact assessments (EQIS). Conducted in partnership with Airparif (the Île-de-France air quality observatory), this study aims to characterize trends in mortality attributable to exposure to anthropogenic air pollution over the past ten years in Île-de-France, and to assess the expected benefits if the concentrations observed in 2019 were reduced to the levels recommended by the World Health Organization (WHO). It also includes an analysis of the impact of the restrictions implemented in 2020 in response to the health crisis linked to the COVID-19 pandemic. Methods - This EQIS is based on the methodological guidelines produced by Santé publique France. The population data used are georeferenced to the building level. Cross-referencing this data with concentrations of PM2.5 (fine particulate matter), NO2 (nitrogen dioxide), and O3 (ozone)—estimated by Airparif for the periods 2008–2010 and 2017–2019 at high resolution—allows for the assessment of population exposure levels, which are then compared to a reference level (minimum level without anthropogenic pollution, World Health Organization (WHO) recommendations, modeled levels). The proportion of deaths attributable (or preventable) to this difference is estimated using relative risks derived from the literature (recent meta-analyses). This proportion, relative to the number of deaths observed in the population (reference years 2004–2008 and 2011–2015), allows for estimating the impact in terms of the number of attributable (or preventable) deaths as well as the average loss (or gain) in life expectancy. Results - Between 2010 and 2019, the annual number of deaths attributable to prolonged exposure to PM2.5 fine particulate matter, one of the main air pollutants, fell from 10,350 [3,840–15,660] to 6,220 [2,240–9,650], representing a 40% decrease. This corresponds to an increase in life expectancy of nearly eight months on average per capita in Île-de-France. If new measures were taken to reduce current air pollution levels below WHO guideline values, more than 7,900 [2,240–13,630] deaths could be prevented each year on average in Île-de-France, representing the combined impact of PM2.5 and O3 (2019 figures). Conclusion - These figures help to objectively assess the public health challenge posed by air pollution and can be used to inform stakeholders, guide public policies aimed at improving air quality, and promote social acceptance of such measures.