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|關鍵字:||PM2.5;PM2.5;PM2.5-10;Sulfate;Nitrate;Ammonium;The spatial variations;Asian dust storms;PM2.5-10;硫酸鹽;硝酸鹽;銨鹽;空間變異性;沙塵暴||出版社:||環境工程學系||摘要:||
研究結果顯示秋冬各測站PM10濃度皆較夏季高兩倍以上，微粒組成以細微粒為主，然3月份適逢大陸沙塵暴侵襲，各測站粗微粒之濃度明顯增加。水溶性離子特性上，採樣期間硫酸鹽於PM10中之含量介於6 ~ 12 %，其空間變異性小，且較前兩年同時期的硫酸鹽濃度含量少，顯示台電電廠SO2排放減量有助於中部硫酸鹽的改善，然而硝酸鹽含量較前兩年增加約0.3 ~ 4.5 %；尤其秋冬PM10高污染時期硝酸鹽和NO2濃度大幅增加，可能是交通污染源的影響；銨鹽的區域性分佈及空間變異性與硫酸鹽相似。然而內陸地區由於風速低，污染物擴散不易，其PM10濃度高於台中都會及沿海地區，尤其在高污染時期，細粒及硝酸鹽的濃度明顯上升；沿海地區SO2和硫酸鹽比例明顯較其它地區高，顯示台中電廠對沿海硫酸鹽濃度有影響但是沿海地區風速大，PM10濃度及空氣品質皆較其它地區良好。
Eight sampling sites in the Central Taiwan were chosen to collect PM2.5 and PM2.5-10 samples from August 1999 to March 2000. Sampling stations included Wuchi coastal station, Chunglun and Changhwa urban stations, Tsaotun, Nanton, Chushan, Puli, Shuantung and Peishan stations in the inland area. In this research, dichotomous samplers were used to collect aerosol samples during daytime and nighttime period. Water-soluble ionic species in particulate phase were analyzed with ion chromatography. Aerosol data were then evaluated with air-quality and meteorological data in order to investigate the seasonal and the spatial variations of sulfate, nitrate and ammonium particulates in the Central Taiwan.
Results showed that average PM10 concentrations in autumn and winter were about two times higher than those in summer. PM2.5 concentrations were usually greater than those of PM2.5-10. However coarse particulate matters (PM2.5-10) increased significantly in spring 2000 due to the influence of the prevailing Asian dust storms. Sulfate accounted for 6 % to 12 % of PM10. Distributions of sulfate were relatively uniform in the Central Taiwan as compared with those of nitrate. Sulfate concentrations measured in 1999 ~ 2000 were lower than those obtained in 1997 ~ 1998. Reduction of SO2 emissions from the Taiwan Electric Power Plant during this period might influence the local ambient sulfate concentrations. On the contrary, nitrate concentrations were 0.3 ~ 4.5 % higher. Particularly, the concentrations of nitrate and NO2 increased significantly during PM10 episodes in the autumn and winter, probably due to the traffic related emissions. Ammonium displayed similar spatial variation of sulfate. PM10 concentrations in the inland areas were found higher than those in the coastal and the urban areas. Such variations may be attributed to lower wind speed in the inland area. Although higher wind speed was often recorded at the coastal site, SO2 and sulfate percentage in PM10 were apparently higher as compared with the other sites in Central Taiwan. These results provided evidence for the role of the Electric Power Plant in the high emission levels in the coastal area .
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