Following a period of major air pollution in January-February 1989, the Erpurs program was established to evaluate health effects related to urban air pollution in the Paris area. Mortality data was gathered from an exhaustive national registry for Paris and its close suburb residents from 1987 to 1998 and related to various air pollutants. The methods consisted in analyzing temporal variations of air pollutant levels with those of daily death counts. Mortality risks during days with pollutant levels higher than the yearly median were compared with mortality risks during the 18 days with the lowest levels. Mortality increases associated with increase in fine particulate matters were 4.7% for respiratory deaths.