The assessment of the health impacts of air pollution on the urban areas of Orléans and Tours presented in this report is fully in line with the guidelines of the Regional Air Quality Plan for the Centre region, which sets out strategies to prevent, reduce, or mitigate the effects of air pollution. The short-term health impact of air pollution was calculated in terms of morbidity (hospital admissions in 2002 and 2003) and premature mortality. Long-term mortality was also studied. The estimated numbers of cases are: - Orléans: 11 [2–23]* hospitalizations for respiratory reasons, 26 [16–36]* for cardiovascular reasons, and 59 [36–84]* long-term deaths; - Tours: 11 [3–22]* hospitalizations for respiratory reasons, 34 [20–48]* for cardiovascular reasons, and 61 [37–86]* long-term deaths. Calculations of the health benefits associated with various air pollution reduction scenarios show that the scenario involving a 25% reduction in the annual average concentration of the pollutant in question is the most effective measure. This study shows, in particular, that health effects occur at pollution levels lower than those for which measures are currently being taken, and that the most effective actions would therefore be those that combine daily reductions in emissions at the source with a decrease in the number of pollution peaks. * 95% confidence interval (R.A.)