Long-term observation of ambient particulate matters in Taichung urban area

• Main Authors: Hsiao-Ling Wang, 王曉玲
• Other Authors: 鄭曼婷
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/42774493933569603841

碩士 === 國立中興大學 === 環境工程學系所 === 97 === Atmospheric particulates were mainly derived from natural and anthropogenic emission sources. The chemical compositions and size distributions of particulate matters can affect visibility, climate and human health . Therefore in this study, aerosol samples were collected by using dichotomous samplers from 2002 to 2008 in Taichung urban area. The samplers were then further analyzed to determine the chemical compositions in order to investigate the characteristics and sources of particulates. The results of this study showed that annual mean concentration of PM10 was 63.9 ± 31.0 μg m-3. The ratio of PM2.5/PM10 was 0.64. SO42-, NO3- and NH4+, were the major species of the particulates which indicated that the ambient particulates were dominated by fine particles and secondary aerosols. During the sampling period, there were 4 agricultural waste burning events. During these events, Cl-, K+, NO3-, OC and EC in PM2.5 were the important marking pollutants. Their concentrations were 10.3 , 6.4 , 4.7 , 4.2 and 3.2 times higher as compared to those in the normal days. Furthermore, there were totally 11 Asian dust storm events. In these events, the concentrations of PM2.5-10 were 2.0 ~ 3.3 times higher than the non-dust storm periods. Sea-salt species Na+ , Cl- and crustal species Mg2+ and Ca2+ were 0.7 ~ 3.2 , 1.1 ~ 5.1 , 1.0 ~ 3.6 and 1.0 ~ 5.2 times higher as compared to those in the non-dust storm events. Therefore the major increased contents in the dust-storm events were coarse particle, sea salt and crustal element. In conclusion, agricultural waste burning and dust storm were the major causes for high pollution. But in normal days, the secondary aerosols were the major sources.