The study area
The study area was defined as the 3.5 km radius circle around the two incinerators (the central point was the middle distance between the two) (Figure 1), on the basis of the previous literature [8,10] and the results of the dispersion model (see below). Most of the area included in the study is used for agriculture; the remaining territory and the borders of the urban area are occupied by three small industrial areas and by an urban district of the city of Forlì. Besides the incineration plants, the other main sources of air pollution are traffic (from urban area and two major roadways), and domestic heating during winter.