WRF-Chem is a non- hydrostatic model running once daily at the National Observatory of Athens (1200 UTC cycle). One domain is used covering a large part of Sahara (main source of mineral dust), the Mediterranean and Europe, with 20 km horizontal grid increment. For the execution of the model, initial and boundary conditions data from the U.S-GFS global model are used, kindly provided by the U.S. Weather Service.