Since 1997, the Air and Health Monitoring Program (Psas) of the French Institute for Public Health Surveillance (InVS) has been quantifying the short-term impacts of urban air pollution. To this end, it relies on time-series analyses conducted according to a standardized protocol in nine French urban areas: Lille, Le Havre, Rouen, Paris, Strasbourg, Bordeaux, Lyon, Toulouse, and Marseille.