Sulfur isotopic compositions and source identification of atmospheric sulfur dioxide, sulfate in aerosols and in bulk precipitation collected over Kyushu Island, Japan

摘要

The #delta#~(34)S values of atmospheric SO_2, and of SO_4~(2-) in aerosols and in bulk predcipitation collected over Kyushu Island were measured, and the sulfur sources were identified by comparing emitted from lcoal sulfur sources such as petroleum combustion or fumaroles, suggesting that the contribution of the local sources to the atmosphere is relatively large. The #delta#~(34)S_(nss) values of nss-SO_4~(2-) in aerosols and in bulk precipitation showed seasonal variations with a maximum in winter. The high #delta#~(34)S_(nss) values observed in winter could not be explained only by an isotopic fractionation effect during the oxidation of SO_2 and SO_4~(2-), suggesting that SO_4~(2-) with high #delta#~(34)S values must be present. It is considered that the desert soil SO_4~(2-), and SO_4~(2-) from coal combustion with high #delta#~(34)S values are transported form continental Asia to Kyushu Island by the northwest seasonal winds in winter, so that the #delta#~(34)S_(nss) values become high in winter. The results indicate that there is strong possibility of long-range transport of SO_4~(2-) from continental Asia to Kyushu Island.