Each summer forest fires in southern Europe emit large quantities of pollutants to the atmosphere. These fires can generate a number of air pollution episodes as measured by air quality monitoring networks. We analyzed the impact of forest fires on air quality of specific regions of southern Europe. Data from several summer seasons were studied with the aim of identifying air pollution episodes related to the occurrence of forest fires. Emissions from forest fires were estimated on the basis of vegetation burned and fire characteristics. Emissions from aircrafts used to fight forest fires were also calculated. It was possible to identify and quantify several particulate and photochemical air pollution episodes caused or enhanced by smoke from forest fires. A case study is described and a mesoscale air quality modelling system, specifically adapted to forest fires, was applied to simulate the fire impact on air quality. Results from the modeling exercise were considered to be reasonable when compared to air concentration values from monitoring networks, taking into account all the uncertainties inherent to this kind of simulation.