Model simulations of the air quality in Athens, Greece, during the MEDCAPHOT-TRACE campaign

Simulations with a three-dimensional time-dependent coupled photochemical and meteorological model are presented. Three days, chosen from the experimental phase of Mediterranean Campaign of Photochemical Tracers-Transport and Chemical Evolution (MEDCAPHOT-TRACE) are simulated. The three days include the two main characteristic flow patterns in the Athens region. On the 12 September 1994 there was a strong northerly flow and the Athens Basin was well ventilated with resulting low pollution concentrations in the city. On the 14 and 15 September, several sea-breeze circulations were formed and high pollution levels were observed in the whole basin with maximum ozone concentrations in the north. A large number of stations were measuring both meteorological and chemical parameters during the experiment. The model results are compared with the ground-based measurements and observed features are explained with the model results. A statistical evaluation of the model performance is also presented and the skill of the model is examined.