抄録
In this paper we describe the results of a long-term observation on the particulate sulfate in the atmosphere over Sakai, Osaka, Japan. Since 1986 an atmospheric particulate sample has been collected daily on the quartz fiber filter in the urban area of Sakai. After extracting ultrasonically water soluble materials from the obtained sample into deionized distilled water, concentrations of sulfate and so on were determined by applying ion chromatography method. Monthly mean concentrations of non-sea salt (nss-) and sea salt (ss-) sulfate for a period of ten years from January 1986 to December 1995 were estimated from the observed concentrations. Using the least squares method, we determined the coefficient values of the linear function expressing concentration variation of nss-sulfate for the period of ten years. Although the rate is considerably different with the month, the concentration of nss-sulfate for each month has an increasing tendency. Consequently the concentration of nss-sulfate was increasing annually at the rate of 0.22 ± 0.05 μg/m3, and its annual mean varied from 3.5 to 5.7 μg/m3 for these ten years. It can be considered that this cause is the remarkably increasing emission of sulfur dioxide in China.
