Contribution of marine and continental aerosols to the content of major ions in the precipitation of the central Mediterranean

The region of the investigated receptor is situated in the southern part of the Adriatic Sea in the Mediterranean. The measuring station is located on the seashore, which, being considered as a border area, is representative for the qualitative and quantitative estimation of the influence of marine and continental aerosols on the content of major ions in precipitation. In the sampling period, precipitation in the region of the investigated receptor was more abundant during the summer and autumn than during the winter and spring. The most frequent precipitation heights were up to 20 mm, while high precipitation came exclusively from the continental region. The results of the measurements of ions readily soluble in water were used for the differentiation of marine from continental contributions of primary and secondary aerosols to their content in the precipitation. Using PCA, it was shown that main contribution of Cl-, Na+ and Mg2+ came from primary marine aerosols, while the contribution from continental sources was dominant for the content of SO42-, NO3-, NH4+ and Ca2+ in the precipitation. The continental origin of Ca2+ was from a primary source, while SO42-, NO3- and NH4+ were representatives of secondary aerosols produced by reactions between acid oxides and alkaline species in the atmosphere, but SO2- and NO3- also exist in the precipitation as free acids. The origin of the trace elements Cd, Cu, Pb and Zn in the precipitation came from anthropogenic emission sources. The results obtained in this work are based on experimental data from 609 samples collected during the period 1995-2000. (c) 2006 Elsevier B.V. All rights reserved