Characteristic of Seashore Atmospheric Aerosol Sampled in Southern Taiwan

• Main Authors: Shih-Chieh Chen, 陳士傑
• Other Authors: Shui-Jen Chen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/30015596810691238815

碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 99 === 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).