Annual simulation of secondary pollution over northern Italy

A secondary pollution modelling system for simulating airborne dispersion and chemical reactions is applied over a regional scale domain located in the North-West of Italy, where urban and industrial areas are present. It was found an overestimation of NO(2) in the urban areas, probably due to an underestimation of the vertical diffusivity; the analysis of O(x) confirms that the discrepancies in O(3) and NO(2) are mainly due to local scale effects; the model shows a general underestimation of the observed PM10 concentrations due to the uncertainties in the emission inventories, spatial resolution, and the adopted aerosol modelling approach