Numerical Air Quality Modelling along the Brenner South Route within the Alpnap Project

The paper presents some preliminary results from numerical simulations of meteorological processes and air pollutant transport based on field measurements perfomed during winter 2006 at three target areas along the Adige Valley (Northern Italy) within the project ALPNAP, funded by the European Regional Development Fund under the initiative Interreg III B "Alpine Space"(cf. de Franceschi and Zardi, 2007). The model CALMET has been used for simulation of the meteorological fields over a domain of 40x95 km, including all the three target areas. As a second step, based on the output from CALMET, the simulation of pollutant dispersion processes has been carried out by means of the Eulerian-Lagrangian model CALPUFF, including a complete complex-terrain module. Data from intensive observations have been used for model calibration, with special emphasis on vertical temperature profiles and turbulence parameters. SODAR data have been used as upper air sounding for an initial-guess wind field. The results shown here consist of NOx concentration fields within subdomains of about 15x10 km at the three target areas of the field measurements. The model output allow to appreciate how local features affect the transport of pollutants emitted by the motorway. The comparison between model results and observed data shows, on average, a good agreement with only some underestimations of the concentration during traffic peaks very close to the source.