目前火力發電的裝置容量以及發電比例均達60﹪以上，是最主要的發電方式。近年來由於對環境品質的要求日益提昇，故環保署於1994年公告之「電力設施空氣污染物排放標準」訂定了更嚴格的排放標準，而位於中部地區之台中火力發電廠，更新後之硫氧化物排放標準自1999年7月開始施行，為了解台中火力發電廠在硫氧化物上的減量成效，與減量後對鄰近地區的改善情況，本研究以順軌跡模式（CTx v0.73）與ISC模式，模擬1997年至2000年地面SO2月均值濃度分佈狀況，以了解季節對污染物分佈之影響，並探討電廠在陸續加裝污染防治設備後，對原生性污染物的改善成效。 由模式模擬結果發現，台中電廠貢獻之地面SO2濃度呈逐年下降的趨勢，從電廠SO2月均值濃度分佈圖來看，電廠對中部地區貢獻之SO2濃度由1997年平均5~10ppb下降至1ppb以下，且由台中電廠附近地區－和美、鹿港、線西、伸港、梧棲等五個地面測站中，台中火力發電廠對上述測站在1997年至2000年間之貢獻比率亦呈現降低的趨勢，其中，以鹿港測站減少85﹪的貢獻最具成效，和美、線西、伸港以及梧棲測站分別下降了66﹪、77﹪、76﹪以及80﹪，顯見台中電廠排放減量對於地面SO2濃度的下降明顯有很大成效。通霄電廠在1997年以及2000年對地面SO2濃度的貢獻並沒有太大的變化，平均約有5~10ppb左右的貢獻，主要影響範圍以通霄附近向南延伸40㎞之沿海一帶較為嚴重。 在氣象條件方面，SO2濃度除了受降雨的沖刷而降低之外，混合層高度的消長與電廠污染物的擴散有決定性的影響，此外，太陽輻射量的強弱亦會造成擴散至地面SO2濃度的高低。 Burning of coal supplies more than 60﹪ of the electricity generated in Taiwan. Coal-burning utilities have responded to evolving clean air standards in a number of ways, including adding flue-gas desulfurization（FGD）to existing plants or switching to lower sulfur coals. Most of the SO2 emissions from coal-fired power plants－and almost half of all SO2 emissions－would be eliminated if all power plants were held to the new plant standards. The new emission standard imposes much stricter emissions limits on coal-burning power plants. In order to determine the effect of power plant SOx reduction strategies and the resulting change of surface SO2 concentration distribution, this study used the Circuit trajectory transfer coefficient model（CTx v0.73）and ISC model to simulate the period of 1997 to 2000. The results show that the contribution to surface SO2 concentration from the Taichung power plant has gradually decreased and the impact from the Tunghsiao power plant has become more important. The comparison between 1997 and 2000 from the Taichung power plant indicated a decrease from about 5~10ppb to 1ppb. When applied in the Homei, Lukang, Hsienhsi, Shenkang and Wuchi regions it also indicated that the Taichung power plant contribution in 2000 was about 66~85﹪ lower than 1997. The main area affected by the Taichung power plant emission is the cities of Changhwa and Taichung. The Tunghsiao power plant contributed 5~10ppb of SO2 from along the Taichung county seashore area to the Datu Hill. Meteorological conditions play an important role in the dispersion of air pollutants. In this study, SO2 levels from the power plant have been found to be affected by mixing height and solar radiation.
