Background: The objective of this study was to quantify the short-term effects of air pollution on mortality and to assess the feasibility of establishing an epidemiological surveillance system in nine French cities. Methods: The collection, processing, and analysis of time-series data followed a standardized common protocol. Pollution data depended on the development of local monitoring networks (measured indicators, number of stations). The analytical techniques used (time-series studies) employed generalized additive models (GAMs). Results: In the 9 areas considered, associations were observed between all-cause, cardiovascular, and respiratory mortality and pollution indicators. These associations were generally linear without a threshold. Overall, excess mortality associated with an interquartile increase in acid-particulate pollution varied, depending on the pollutant, between 0.3% and 3.5% for total mortality; 0.5% and 6.3% for cardiovascular mortality; and between 0.1% and 12% for respiratory mortality. Regarding photo-oxidative pollution, these ranged from 0.4% to 7.3% for total mortality, 1.4% to 6.7% for cardiovascular mortality, and 1.7% to 30.4% for respiratory mortality. Conclusion: Despite a standardized common protocol, certain disparities, inherent to local characteristics, were observed (length of time series, number of monitoring stations and available pollutants, etc.). Nevertheless, this pilot study demonstrated that multicenter epidemiological surveillance of the effects of air pollution is feasible. However, this requires validating the results obtained through a new analysis of mortality data over a longer study period, as well as examining the feasibility and relevance of using other health indicators such as hospital admissions.