This assessment was conducted as part of the Air Quality Protection Plan (PPA), which sets out guidelines aimed at preventing, reducing, or mitigating the effects of air pollution. It was carried out using a standardized method proposed by the InVS, which is based on epidemiological data establishing a link between air pollution and health. The short- and long-term health impacts of air pollution were estimated in terms of morbidity (hospital admissions) and premature mortality over the 2004–2005 period. The study area consisted of the 38 municipalities covered by the Nancy PPA, representing a population of approximately 330,000 residents. The short-term health impact attributable to air pollution was estimated annually at 43 premature deaths across all age groups, 20 hospital admissions for respiratory causes, and 42 hospital admissions for cardiovascular causes among adults aged 65 and older. The results of the scenarios studied showed that eliminating only the pollution peaks over the course of a year would have a short-term and long-term impact far less significant than reducing the daily average pollution level. This study provided an order of magnitude for the serious health effects of air pollution that led to hospitalization or death. It underestimated the actual health effects because it did not account for emergency room visits or conditions treated in outpatient settings, which affect a larger portion of the population. This study demonstrated that health effects occur even at low pollution levels that meet quality standards. In terms of public health, the most effective preventive measure is the daily reduction of pollution levels by cutting emissions at the source, primarily in the industrial, transportation, and commercial/residential sectors. (R.A.)