The impact of thermodynamic module in the CTM performances

This work investigates the impact of the inorganic thermodynamic module on Chemical Transport Model simulations. The study has been focused on Northern Italy, one of the most polluted area in Europe, where high PM10 levels are reached despite the Regional and National Authority efforts to limit emission in the atmosphere.Two different configurations of the Chemical Transport Model TCAM have been tested performing yearly simulation over the selected domain for 2005. In the first configuration, the SCAPE2 thermodynamic module has been implemented, while in the second one, ISORROPIA-II has been integrated into the system.An exhaustive evaluation of the performances is presented for total PM10 with respect to its daily values, and the analysis of the impact of the two modules on PM2.5 and on aerosol chemical components has been performed.The ISORROPIA-II module configuration shows better overall performances both in terms of correlation and Normalized Mean Absolute Error for PM10 and PM2.5. The evaluation of the inorganic ions performances shows a quite different behavior for the two configurations, with ISORROPIA-II providing better results for both Normalized Mean Absolute Error and Normalized Mean Error.

► The impact of the thermodynamic module in a Chemical Transport Model has been evaluated. ► The role of secondary inorganic fraction on PM10 levels has been assessed. ► The impact of the different chemical species in aerosol performances has been shown.