For the first time, Santé publique France has conducted a quantitative assessment of the health impacts of long-term exposure to ambient air pollution in mainland France, focusing on the incidence of respiratory, cardiovascular, and metabolic diseases. In partnership with the Aix-Marseille School of Economics (Aix-Marseille University - CNRS), the study also provides an economic assessment of these impacts (Volume 2). The study complements the findings on mortality published in 2021. The impact on the development of eight of the ten conditions proposed by the WHO’s EMAPEC project was examined here, based on available data, under various scenarios for reducing ambient air pollution in mainland France: for respiratory conditions: lung cancer, chronic obstructive pulmonary disease (COPD), asthma in children and adults, pneumonia, and acute lower respiratory tract infections (excluding influenza) (ALRI); at the cardiovascular level: stroke, acute myocardial infarction (AMI), hypertension; metabolic diseases: type 2 diabetes. It should be noted that only the long-term effects of exposure to ambient air pollution (AAP) on morbidity indicators were estimated in our study, which shows that long-term exposure to PM2.5 and NO2 has a significant impact on the incidence of new cases of the diseases considered within the studied populations. In the context of the adoption of new European directives on ambient air quality, which bring air quality standards closer to WHO recommendations without fully meeting them, these results provide information to guide prevention efforts aimed at reducing exposure to air pollution and better protecting the health of the French population. Santé publique France maintains that compliance with WHO guideline values would reduce mortality and morbidity attributable to air pollution in France, contributing to the achievement of the WHO’s “ Global Action Plan for the Prevention, Control and Treatment of Noncommunicable Diseases 2013–2020 ," namely a 25% reduction in premature mortality linked to these diseases by 2025.