The scientific knowledge accumulated to date regarding the health effects of air pollution makes it possible to propose a method for quantifying these effects in terms of the number of attributable cases in the general population. This document presents the concepts underlying the assessment of the health impacts of air pollution, as well as the recommended practical procedures for its implementation by the Air and Health Monitoring Program (Psas). With regard to the latter, the information presented pertains solely to the assessment of the health impacts of outdoor air pollution in urban areas. This document updates the series of guides on conducting health impact assessments of air pollution published by the InVS since 1999, in particular to assist in assessing the effects of air quality on health within the framework of the Regional Air Quality Plans (PRQA) (R.A.)