Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/5587
標題: 台中地區酸性濕沈降的研究
作者: 巫培任
關鍵字: 加權pH年平均值;年平均加權濃度;酸性濕沈降通量
出版社: 環境工程學系
摘要: 
本研究主要探討台中地區濕沉降的化學組成和濕沈降通量,雨水的樣本取自沙鹿、大里及東勢林場三個測站,採樣期程從2002年5月至2003年4月,總共收集182個雨水樣本,主要分析雨水的pH值、Cl-、NO3-、SO4=、Na+、NH4+、K+、Mg2+及Ca2+濃度。
台中地區雨水偏酸性,其加權pH年平均值為4.70,SO4=和NO3-年平均加權濃度分別為42.0及32.2 μeq L-1,與過去(1991年~1999年)台中港地區雨水數據比較,目前SO4=減少0.5倍,然NO3-則增加約1.2倍。與東亞國家日本及韓國比較,其SO4=濃度差異甚小,然本地NO3-濃度則分別高出2.1及1.3倍,顯示中部地區雨水中NO3-濃度偏高,彰顯移動性污染源所產生的影響。中和物種NH4+及Ca2+年平均加權濃度分別為44.0及15.7 μeq L-1,和台中港往年相比NH4+亦有偏高之情形。採樣期間三測站雨水酸化程度差異性並不大,其平均pH值介於4.69和4.71之間。但雨水中的SO4=和NO3-加權平均值有明顯空間上之差異,其中大里測站SO4=和NO3-濃度分別為51.5和41.0 μeq L-1,為沙鹿測站的1.7及2.2倍,然大里測站於採樣期間Ca2+濃度偏高,導致該地區在採樣期間雨水的酸化程度與其他兩站相似。
冬季時期台灣地區盛行東北季風,在此季風下台中地區境內雨水SO4=濃度均較其他季節高,除了SO4=之外其他污染物濃度也均有明顯增加,尤其沙鹿測站和東勢測站SO4=/NO3-增加較為顯著,而在人口及車輛密集的大里測站則較不明顯。在酸性濕沈降通量方面,大里測站nss-SO4=為32.8 Kg ha-1 yr-1,東勢測站為24.4 Kg ha-1 yr-1,沙鹿測站為15.8 Kg ha-1 yr-1。NO3-仍以大里測站最高,其次為東勢測站及沙鹿測站,其值分別為35.0 Kg ha-1 yr-1,27.1 Kg ha-1 yr-1,13.2 Kg ha-1 yr-1。

This study mainly investigated the chemical compositions and the deposition fluxes of wet precipitation in Taichung area. The rain samples were collected at the three stations - Shalu, Tali, and Tungshih forest. The sampling program started from May 2002 to April 2003. Totally 182 samples were collected for analyzing the pH and the concentrations of Cl-, NO3-, SO4=, Na+, NH4+, K+, Mg2+ and Ca2+. The average volume-weighted pH value in Taichung was 4.70 and the volume-weighted concentrations of SO4= and NO3- were 42.0 and 32.2 μeq L-1, respectively. SO4= concentration measured in this study were only 50 % as those obtained in 1991~1999. However NO3- concentrations were 20 % higher. No much difference was found in SO4= concentrations by comparing the data obtained in Taichung and in East Asia countries (Japan and Korea). But NO3- concentrations were nearly two times higher which indicated that the vehicular emissions in Taichung might affect the compositions of the precipitation. By comparing the data obtained at the three stations, it was found that the concentrations of SO4= and NO3- and the neutralizing Ca2+ at Tali station were much higher than those at Shalu and Tungshih stations. As a result the pH value at the three stations were all in the range between 4.69 and 4.71. Furthermore, the wet deposition fluxes of nss-SO4= at Tali, Tungshih and Shalu were 32.8, 24.4 and 15.8 Kg ha-1 yr-1, respectively. Similarly, the wet depositions of NO3- were 35.0, 27.1 and 13.2 Kg ha-1 yr-1, respectively.
URI: http://hdl.handle.net/11455/5587
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