南台灣沿海地區大氣氣膠特徵探討

Characteristic of Seashore Atmospheric Aerosol Sampled in Southern Taiwan

陳士傑(Shih-Chieh Chen)

指導教授 ： 陳瑞仁

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2011年)

https://doi.org/10.6346/NPUST.2011.00163

摘要

本研究於2010年3至4月間，在屏東縣車城鄉海洋生物博物館旁以分道採樣器(Dichots)及微孔均勻沈積衝擊器(MOUDIs)採集大氣微粒，以探討南台灣沿海地區大氣微粒組成特性。研究結果顯示： 無論以石英或鐵氟龍濾紙採樣，Dichots測得之PM2.5及PM2.5-10濃度與MOUDIs之測值相近；且MOUDIs及Dichots以石英濾紙採樣時，其PM2.5及PM2.5-10濃度均較鐵氟龍濾紙之測值稍高。2010年ADS影響期間，屏東沿海地區PM10及PM2.5濃度約為ADS來襲前、後(即Non-ADS)測值之2倍；PM10及PM2.5濃度之提高主要來自1.0～5.6 μm粒徑上濃度增加所貢獻。無論在ADS與Non-ADS期間，在超細(PM0.1)粒徑上兩期間測值差異甚小；當粒徑在1.0 μm以上時，隨微粒粒徑增加，兩者質量差增大。
屏東沿海大氣PM2.5-10上水溶性離子總濃度中約有一半以上是由Cl–與Na+(海鹽成分)所貢獻；PM2.5上則主要是由SO42–及NH4+(二次氣膠)所組成，其佔全部水溶性離子總濃度之比例達70%；除K+及SO42–呈雙峰分佈(其峰分別位於0.56~1.0 μm及3.2~5.6 μm上)外，微粒上Na+、NH4+、Mg2+、Ca2+、Cl–及NO3–均呈單峰分佈；Na+、Mg2+、Ca2+、Cl–及NO3–其峰均位於3.2~5.6 μm上，NH4+之峰位於0.56~1.0 μm上；而PM0.1、PM1.0、PM2.5及PM2.5-10各粒徑微粒其OC/EC值均大於2。屏東沿海PM0.1、PM1.0、PM2.5及PM2.5-10各粒徑微粒上金屬之濃度有98%以上來自地殼元素所貢獻(98.4~99.1%)，而來自人為排放金屬之濃度僅佔極小比例；且PM10上其金屬總濃度中有60%以上存於PM2.5-10。與Non-ADS相較，ADS期間其各粒徑微粒上Metals/PM值均有增加，且以PM2.5-10增加之比例(2%以上)較多；在PM2.5-10以Ca之含量增加最多、Fe次之、Al再次之，而在PM2.5上則以Ni增加最多、其次為Al與Ca。由加強因子(Enrichment Factor)分析推估各粒徑PM上Na主要來自海水飛沫，Al、Fe、Ti、Mn及Ba等主要來自地殼，Zn、Cd、Sb及Ag等則主要來自人為污染源所貢獻；Mg、K、Ca及Sr可能來自地殼及海水飛沫，而Ni、Cr、Cu及Pb等成分之來源有地殼及人為污染源兩種。沿海大氣PM0.1、PM1.0、PM2.5等細粒徑微粒分析之水溶性離子、EC、OC及金屬等物種質量和佔PM比例較高，在Non-ADS時其平均值79.3±3.14%，ADS時其值則為79.8±9.00%；在粗微粒(PM2.5-10)上其值則較低僅分別為63.3±5.20 (Non-ADS)及54.3% (ADS)。

關鍵字

粒徑分佈 ； 亞洲沙塵暴 ； 水溶性離子 ； 碳成分 ； 金屬元素 ； 加強因子

並列摘要

The sampling of this study was conducted at National Museum of Marine Biology and Aquarium, Checheng, Pingtung in March and April, 2010. Atmospheric particles were collected using Dichot and MOUDI to characterize the composition of atmospheric aerosols in the coastal area of southern Taiwan. The results showed that the concentrations of PM10 and PM2.5 collected by the MOUDI were very close to those obtained by the Dichot, regardless of using quartz or teflon filters. However, the concentrations of PM10 and PM2.5 collected using quartz filters were slightly higher than those collected by teflon filters. In 2010, the concentrations of PM10 and PM2.5 sampled during an Asian Dust Storm (ADS) period were about two times that during a non-ADS (pre- and post-ADS) period. The main contribution of ADS particles was those with sizes of 1.0–5.6 μm. The concentration of ADS ultrafine (PM0.1) was similar to that of Non-ADS . However, the concentrations of ADS micrometer particles (PM＞0.1) noticeably higher than that of Non-ADS , and such concentration difference between ADS and Non-ADS particles increased as particle size increased.
More than half of water-soluble ions in coarse particles (PM2.5-10) were contributed by Cl– and Na+ (sea salt), while 70% of water-soluble ions of fine particles were composed of SO42– and NH4+ (secondary aerosols); only K+ and SO42– exhibited bimodal particle size distributions (peaking in 0.56–1.0 μm and 3.2–5.6 μm, respectively), while the particle size distributions of Na+, Mg2+, Ca2+, Cl–, and NO3– were all uni-modal (peaking in 3.2–5.6 μm), and NH4+ was also uni-modal (peaking in 0.56–1.0 μm). The ratios of OC/EC of PM0.1, PM1.0, PM2.5, and PM2.5-10 were all above 2.0. More than 98% of the metals in PM0.1, PM1.0, PM2.5, and PM2.5-10 were crustal elements (98.1–99.1%), and those from anthropogenic emissions were very few. Moreover, more than 60% of metals in PM10 were coarse particles (PM2.5-10). The metal content of ADS particles in all size ranges was greater than that of Non-ADS particles. Such increase in metal content was more significant (more than 2%) for PM2.5-10, and Ca had the greatest increase in content, followed by Fe and Al. For PM2.5, Ni showed the greatest increase in content, followed by Al and Ca. According to Enrichment Factor analysis, Na in PM0.1, PM1.0, PM2.5, and PM2.5-10 was mainly from sea spray; Al, Fe, Ti, Cr, Mn and Ba were chiefly contributed from crustal; most of Zn, Cd, Sb and Ag were from anthropogenic sources; crustal and sea spray probably accounted for particle-bound Mg, K, Ca and Sr ; and Ni, Cu and Pb were attributed to crustal and anthropogenic sources. The sum of percentages of water-soluble ions, EC, OC, and metals was higher in fine particles (PM0.1, PM1.0, and PM2.5), averaging 85.6±5.26% and 85.7±11.4% for the Non-ADS and ADS particles, respectively, while these values were lower for PM2.5-10 (with averages of 66.8% and 53.8% during the Non-ADS and ADS periods, respectively).

並列關鍵字

Size distribution ； Asian Dust Storm ； Water-soluble ions ； Carbon contents ； Metal elements ； Enrichment Factor

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