Numerous epidemiological studies have demonstrated a causal relationship between exposure to urban air pollution and morbidity and mortality. The Assessment of the Health Impact of Urban Air Pollution (EISPA) is part of the revision of the Air Protection Plan (PPA). It follows the methodological approach proposed by the French Institute for Public Health Surveillance (InVS) and considers certain pollutants—markers of air pollution (AP)—routinely measured by the accredited air quality monitoring association in the Centre region (Lig’Air) at its background monitoring stations. These are ozone (O3) and fine particulate matter (PM10 and PM2.5), exposure to which has a well-documented impact on health in the scientific literature. The causal relationship between exposure to nitrogen dioxide (NO₂) and its health impact is not the subject of scientific consensus; this pollutant is therefore not included in the new health impact assessment methodology. (R.A.)