Chapter 5.12 Modelling of aerosol composition using the MARS/MUSE dispersion model

Abstract Among aerosol characteristics, their chemical composition is by far one of the most important and at the same time quite difficult to follow, as it gathers several inorganic and lots of organic species. We present here the aerosol module inserted in the MARS-MUSE 3D dispersion model and some preliminary results for urban areas. In this module, the aerosol phase is described as a multimodal (fine, accumulation and coarse) internally mixed distribution. For inorganics, an equilibrium model has been built especially for dry, coastal and urban regions, which contains common inorganic species and also crustal species. For secondary organics, the SORGAM module has been incorporated into the model. The simulations conducted revealed the capability of the model to describe PM pollution in Southern California. Most deviation from the observed data are probably not exclusively related to the module, but to inaccuracies in emission input data and simulation of meteorological parameters.