How can we accurately model the complex behavior of particulate matter in regional air quality simulations? This paper describes the development and application of an aerosol model, MADE, designed for regional air quality simulations. MADE focuses on the chemical composition and size distribution of atmospheric particulate matter. The aerosol model MADE is based on a modal concept and describes the chemical composition and the size distribution of atmospheric particulate matter. Primary as well as secondary aerosol components are considered in the model, which is fully integrated into the photochemical transport model EURAD. Simulations show the potential importance of secondary organics of anthropogenic and biogenic origin for the tropospheric particle loading. The model system has been applied to a European domain with different resolutions, using a one‐way nesting procedure. In addition it is shown that a reduction in precursor emissions for the inorganic ion fraction of PM does not necessarily lead to an equivalent reduction in PM2.5 mass concentrations, as for example a reduction in sulphate aerosol caused by reduced SO2 emissions might be compensated by enhanced formation of nitrate aerosols in certain regions.