Using and evaluating numerical models which simulate different emission scenarios targeted at determining the change in the oxidative capacity of the atmosphere in Europe, as detailed below. The analysis of the results will enable the selection of representative cases of study to contrast experimentally within Subproject 1. Besides the comparison of the model results with observations and from air quality stations across Europe and taking into account the results obtained at EUPHORE will include a sensitivity analysis to BVOC emissions. Besides, the outcomes from EUPHORE experiments will be valuable to identify future lines of investigation and to make recommendations for the revision of the air quality modelling system.