A target-oriented risk assessment for air pollution in Milan: Preliminary results

A simplified risk assessment procedure has been developed to evaluate the air quality impact on specific population targets (target-oriented assessment) in the city of Milan (Italy). Pressure elements (pollutant emissions from different sources) and vulnerability factors (related to population density and susceptibility) have been considered and integrated with different weight coefficients according to their relevance. A linear combination of the pressure and vulnerability factors inside a grid of square cells has generated a risk distribution map of the selected territorial domain. On the basis of the final risk map, a statistically significant number of sites have been selected, on which concentration measurements (during two separate summer and winter campaigns) of the main urban air pollutants have been planned. The first monitoring campaign has been carried out in summer 2008 with a time extension of 2 months ( July-August 2008). Mean weekly concentrations of nitrogen dioxide (NO ₂), ozone (O ₃) and benzene (C ₆H ₆) have been recorded by using diffusive samplers. PM10 daily concentration have been determined in five sites of the urban area, along with the heavy metal composition of the collected samples. The project methodology and the preliminary experimental results of the first (summer) campaign are presented.