SULFUR ISOTOPE VARIATIONS IN ATMOSPHERIC SULFUR OXIDES, PARTICULATE MATTER AND DEPOSITS COLLECTED AT KYUSHU ISLAND, JAPAN

摘要

Atmospheric sulfur oxides, pariticulate matter and deposits (wet and dry deposits) were collected from July 1998 to June 1999 at Kyushu Island, Japan. The isotopic composition of sulfur (δ~(34)S) was measured to identify the source of sulfur in the samples. The monthly δ~(34)S values were always low in the order of the sulfur oxides, sulfate in particulate matter and deposits. The δ~(34)S values of the sulfur oxides ranged from -2.7 %o to -0.4 %o and were close to those of fossil fuels used in Japan. The δ~(34)S values of sulfate in the particulate matter and deposits correlated with seasalt contribution, so that the δ~(34)Snss value was calculated for non-seasalt sulfate. The δ~(34)Snss values of sulfate in the particulate matter and deposits trended higher in winter than summer, suggesting the possibility of isotopic fractionation during chemical transformation (SO_2 to SO_4~(2-) ) and of contribution of sulfate derived from sulfur sources with higher δ~(34)S values.