摘要：针对台湾中部都会区4县市环境负荷日益严重、导致空气质量日益变化、污染源特性依县市而异,例如:露天燃烧、河川裸露地的扬尘、污染源排放量掌握的不确定性、污染物传输及污染来源的成因未明确等问题,为了研究各地污染特性、地形、气象等因素对空气质量影响,针对台湾中部地区污染源、地形与天气类型进行模式模拟。研究采用逆轨迹模式(back trajectory models),模拟中部地区局部环流及地形效应影响。结果显示:其中臭氧污染的逆轨迹型态与不同时间环境气流有关,而悬浮微粒PM₁₀污染的逆轨迹形态受到当地地形与风速影响,同时伴有境外地区移入污染源的影响。台湾地区春季时,锋前暖区及锋面过境时,因风速小对空气品质造成不良影响。夏季与秋初时期空气质量好,只有遭遇台风影响时各地的空气质量会因位置不同而有差异,其中臭氧浓度于此时变化较大。台风外围环流的影响程度则视太平洋副热带高压的强度及其高压脊所在位置而定。秋末与冬季时期,台湾地区主要受锋面及东北季风影响,中南部地区因位于中央山脉的背风面,风速微弱且日照较强,清晨近地面即易形成逆温层,不利于污染物扩散,空气质量较差。在高压出海及高压回流的天气型态下,因中央山脉的阻挡,西部地区的污染物浓度非常容易累积,尤其是中部及云嘉地区易有污染物浓度高值出现。 

关键词：逆轨迹模式；空气质量；臭氧；悬浮微粒

Abstract：The severe environmental degradation worsens the air quality in central Taiwan. Contaminated by diverse pollutants， such as public burning， dust on bare river-banks， uncertain pollutants， conveyance of pollutants, and uncertain factors of pollutants， different places displayed different situations. The impact to air quality was investigated in accordance to the features of pollutants， topography， meteorology， and the polluting modes was simulated according to pollutants in Central Taiwan, geography， and weather types as well. Adopting the back trajectory models， the effects of circulation and geography in central Taiwan was monitored. The result indicated that the trajectory of ozone （O₃） pollutants related to the transient air current, and the trajectory of particulate matters （PM₁₀） related to topography and wind speed. The pollutants from adjacent areas also affected the results. Due to the slow wind speed， the air quality in spring was unqualified while with the Warm Area ahead of front and Front Passing through. During summer and early autumn， air quality was better but with different presentations in different areas and tremendous transitions on the concentration of O₃ caused by Typhoon. The effects of the circulation surrounding Typhoon was differed by the strength of the subtropical high in the Pacific Ocean and the position of the ridge. During late fall and winter， the front and northeastern monsoon were the principal factors to Taiwan weather. Mid- and south-Taiwan didn't diffuse pollutants with worse air quality because of the usual formations of inversion layer near the ground in the morning. The weak wind， the strong sunshine， and their locations at the lee of the Central Mountain range guide to the layer. Accompanying the outflow and outflow rebound with high pressure， and the blockade of the Central Mountain range， the concentration of pollutants in Western Taiwan was accumulated easily； mid-Taiwan and the areas of Yunlin and Chiayi even had the more pollutants. 

Keywords：back trajectory models； air quality； ozone； suspended particulates