Evaluation by TCAM Model of Physical–Chemical Properties of Aerosol in Northern Italy

Abstract

The chemical and size characterisation of aerosol in northern Italy was investigated by means of transport chemical aerosol model (TCAM) multiphase model longterm simulations performed within the frame of the CityDelta-CAFE exercise. The results show a high contribution of secondary inorganic compounds, in particular far from the Milan metropolitan area and in the large rural area of the Po valley where the major chemical fractions are ammonium and nitrates. The sulphate contribution is quite similar throughout this region, with the exception of areas close to SOx point emissions. Primary PM and organic compounds fractions, on the other hand, are greater close to major urban areas, in particular the Milan metropolitan zone. This work also presents a seasonal characterisation analysis of physical and chemical aerosol features. The results show that in winter, due to domestic heating emission of NOx and low temperatures, which favour the formation of secondary nitrate and organic aerosol, the PM10 and PM2.5 concentrations are higher than those in summer, in agreement with experimental data presented in several studies focussing on the same region.