Physical and Chemical Processes of Polluted Air Masses During Etesians: Aegean-Game Airborne Campaign – An Outline

Gaseous species and aerosol size distribution and chemical composition within the boundary layer during the Etesians is investigated, based upon airborne measurements, over the Aegean Sea, from Crete to Limnos islands (29/8–8/9 2011, Aircraft_BAe146–FAAM). Three flights of a similar route covered the eastern and western parts of the Aegean Sea. Two flights were performed on the same day to study the impact of the diurnal cycle. The sorties involved horizontal tracks mainly at 150 m a.s.l. and above the aerosol layer, at 2.5 km a.s.l., and profiles up to 4.5 km near the ground stations of Crete and Limnos and the Central Aegean Sea. Marked variations were detected in the vertical structure of aerosols and thermodynamic variables between the eastern and western segments flown around the Aegean. Several discrete aerosol layers, separated by a clean slot, containing particles of different chemical composition were observed, with sulfates and organics being the dominant components. CO concentrations ranged from 80 ppb above the mixing layer, up to 140 ppb near the surface. O3 ranged between 50 and 75 ppb, with higher values observed at surface upwind of Finokalia and in the mixing layer in Central and Northern Aegean Sea.