The Regional Air Quality Plan (PRQA), established under the Law on Air Quality and the Rational Use of Energy of December 30, 1996, and whose implementation procedures are specified by the Decree of May 6, 1998, sets out guidelines aimed at preventing, reducing, or mitigating the effects of air pollution. It is based as much as possible on an assessment of the effects of air quality on public health. The Nord-Pas-de-Calais PRQA consists of 54 guidelines. The fifteenth guideline states that “conducting studies for the local assessment of the health impact of air pollution in the main urban areas of the Nord-Pas-de-Calais region covered by a monitoring network” is considered a priority. It is within this framework that the health impact assessment (HIA) of air pollution in the Douai area, presented here, was conducted. The main objective of this study is to provide local stakeholders (decision-makers, associations, residents, etc.) with an estimate of the magnitude of the impact of air pollution in order to set air quality improvement targets based on public health criteria. It also serves as a tool for planning and evaluating public policies, as it allows for the measurement of the effectiveness of preventive measures. It follows the health impact assessment methodology updated by the InVS, in accordance with WHO recommendations. The short-term health impact of air pollution is calculated in terms of morbidity (hospital admissions) and mortality. An estimate of the long-term health impact is calculated in terms of mortality based on the results of international epidemiological studies. In its “results” section, this report first describes the exposure of the population in the study area to air pollution, as documented by air quality measurements from the AREMASSE monitoring network. The development of health indicators then allows for the calculation of the health impacts of air pollution based on the selected indicator. Finally, various scenarios for reducing air pollution are examined. The effectiveness, in terms of health benefits, is compared across different pollution reduction strategies to guide decisions that could influence air quality trends in the observed study area.