Modelling system for photochemical pollution in Northern Italy

The aim of this work is to reproduce long-term, photochemical pollution over a low emission level area (eastern Piedmont valley) near a high emission level area (industrial triangle Milan-Turin-Genoa), by means of an integrated modelling system. In this study, we present the predictions of the photochemical model in reproducing the development of hourly concentration fields starting from meteorological and emissive scenarios. The model is initialised by means of an emission processor and the meteorological fields simulated by a circulation model. Some representative air quality stations have been selected from the monitoring network in order to evaluate the simulation results. The comparison shows a general agreement between computed and measured ozone concentrations, both in urban and rural areas. The discussion of results shows the system capabilities and highlights the possibility to improve the modelling system performances, enhancing both emissive and meteorological input. A comparison between the results obtained using different options for predicting the vertical diffusivity is also shown and discussed.