ATMOSPHERIC TRACE-ELEMENT CONCENTRATIONS OVER THE EASTERN MEDITERRANEAN SEA - FACTORS AFFECTING TEMPORAL VARIABILITY

Concentrations of elements and ions were measured in aerosol samples c ollected between March 1992 and December 1993 at a rural station on th e Mediterranean coast of Turkey. Concentrations of pollution-derived e lements are lower than corresponding concentrations reported for the w estern Mediterranean region, due to the longer distances traveled by t he particles to reach the eastern Mediterranean region. Concentrations of elements vary on timescales ranging from days to seasons. Short-te rm variations in the concentrations of pollution-derived elements are explained by transport from source regions. Short-term variations in t he concentrations of seasalt and crustal elements, on the other hand, are due to the episodic nature of wind-induced particle generation mec hanisms. Transport failed to explain long-term variations due to lack of seasonal changes in air mass transport patterns. The seasonal varia tions in the concentrations of anthropogenic elements are determined b y the wet deposition of particles, which is more extensive in the wet season, and distances between source regions and the sampling Site. Th e long-term variations in the concentrations of crustal and sea-salt e lements are explained by seasonal changes in their source strengths, D istant rains on the path of the air masses which transport anthropogen ic particles to the eastern Mediterranean are more influential on the observed seasonal behavior of pollution-derived elements than local ra in events.