The results of air quality models are highly influenced by meteorology and emission inventory. At high spatial resolutions, the meteorological models can capture in a more realistic way the effect of the orography, the interactions between soil/vegetation and atmosphere, the dynamics of the boundary layer, the sea-breezes circulation in the coastal zones, the formation and evolution of clouds and precipitation, etc. Moreover, the emissions produced using local information can capture better both the spatial and temporal distribution of pollution. This study investigates the change in pollutant concentrations in relation to the change of horizontal grid resolution. The analysis is carried out for stations located in zones with different geographic characteristics (mountain, coast, etc) and of different types (rural, urban). The simulations are performed with the Atmospheric Modelling System (AMS), part of the MINNI modelling system (Italian Integrated Assessment Modelling System), for emissions based on municipal and provincial inventories.