An inverse modeling method to identify vehicular emissions in urban complex areas.

The meteorological model CALMET and the dispersion model CALPUFF were used to predict dispersion of contaminant emitted from industrial, naval and vehicular sources in the Strait of Messina area (Italy). This region is of particular interest in that it relates to the construction of the Messina Bridge, the road infrastructure linking the Italian mainland and Sicily. The modeled domain covers an area of 30x40 Km2, with grid spacing of 250 m. The domain includes two cities, i.e. Messina and Reggio Calabria, and other Urban complexes located mainly along the shoreline. One of the main problem encountered during the investigation was the lack of data regarding the vehicular emissions. Therefore, an indirect method was utilized, and the data of the Urban air quality monitoring stations of the two cities were considered during the procedure. Starting from the Corine Land Cover data base, a hypothetical location of Urban areal emissions was derived and the strength of the sources was deduced by the inverse method. The results show a good agreement with measures at receptors. The method seems to give a valid alternative when network traffic data are not available in Urban areas.