屏东地区大气悬浮微粒及成份之粒径分布.doc

屏東地區大氣懸浮微粒及成份之粒徑分佈 Size Distributions of Particulate and Aerosol Composition in Pingtung Area 研究生：指導教授： 【摘要】 本研究以微孔均勻沉積衝擊器(Micro-orifice Uniform Deposit Impactor；MOUDI)於屏東縣內環保署所屬之屏東(中正國小)及潮州(潮南國小)兩處大氣空氣品質測站進行不同粒徑微粒之採樣，以探討屏東地區大氣懸浮微粒之粒徑分佈及組成特性。研究結果顯示：兩測站於秋冬季期間其微粒之質量濃度均較春夏季時為高，其空氣品質較差；兩測站大氣中之微粒均呈雙峰分佈，其最高峰分別出現於粒徑在0.56 ~ 1.0及1.0 ~ 1.8μm之細微粒(dp1.8μm)上，顯示屏東地區大氣中之懸浮微粒多以細微粒為主。兩測站微粒上之SO4-2及NH4+大致呈單峰分佈，最高峰主要分佈於粒徑在0.56 ~ 1.0μm之細微粒上，其細微粒上之硫酸鹽可能以(NH4)2SO4之型態存在。兩測站微粒上之NO3-大致呈雙峰分佈，在屏東站其主、次峰分別位於細粒徑(0.56 ~1.8μm)及粗粒徑(3.2 ~5.6μm)上；在潮州站其主、次峰則分別位於粗粒徑(3.2 ~5.6μm) 及細粒徑(0.56 ~1.8μm)上。細粒徑上之硝酸鹽可能以NH4NO3之型態存在，而粗粒徑上之硝酸鹽則可能為NO3-與海鹽或其與土壤元素相結合之型態。兩測站微粒上之Cl-、Na+及K+等三種離子大致均勻分佈於粗、細微粒上，而Mg+2及Ca+2則主要分佈在粗微粒(dp1.8μm)上。屏東站微粒上之總碳(TC)大致上呈雙峰分佈，其主、次峰分別位於0.32 ~0.56μm及5.6 ~ 10μm上，且主要分佈於細微粒上；潮州站微粒上之TC則呈三峰分佈，其主峰亦分佈在細微粒上。屏東站於春夏季及秋冬季其微粒上有機碳(OC)與元素碳(EC)之比值(OC/EC)分別為2.89及4.09；而潮州站其微粒上OC/EC之比值則分別為1.70及1.51，其可能與屏東站附近之固定及移動性污染源較潮州地區多有關。兩測站於受大陸沙塵暴影響期間，其微粒上Ca+2之濃度分別為4.15及4.62μg/m3，其值分別為非沙塵暴期間之2.99及2.16倍；而Mg+2則分別增加為平常期間之6.27及4.94倍。 關鍵字：: 懸浮微粒 粒徑分佈 衍生性氣膠 微孔均勻沉積衝擊器(MOUDI) 【Abstract】 This study discussed ambient air particle size distribution and composition characters by using micro-orifice uniform deposit impactor (MOUDI) at Pingtung and Chaochou sampling sites simultaneously. These two sampling sites were all belong to Taiwan EPA monitoring stations. The results revealed that the particle mass concentrations were higher at autumn and winter than those of spring and summer seasons at both sampling sites. The air quality is poor at autumn and winter seasons. For particle of ambient air, bi-peak model distribution occurred at both sampling sites. The highest peak for particle size distribution occurred in the ranges from 0.56 to 1.0μm and from 1.0 to 1.8μm, responding to fine particle size range (dp1.8μm). This results claimed that the distribution of suspended particle was dominated by the fine particle size range (dp1.8μm) in the ambient air of Pingtung. The distribution of both SO4-2 and NH4+ at both sampling sites w