許多研究均指出，區域性大氣污染物會隨大氣運動而長程傳輸至下風處，造成下風處的污染，以北半球而言，大陸及東南亞沿海等地區為世界主要空氣污染物排放源區，春夏季季風盛行時，其污染物朝太平洋方向逸散，帶來東亞地區、乃至全球大氣環境的破壞，具有相當嚴重的程度。此結果對於東亞區域位於太平洋西測的台灣，則首當其衝，因此，評估台灣地區背景空氣品質的影響，極為迫切。本計畫擬以一氧化碳及氟氯碳化物作為指紋氣體，擇以遠離本地污染影響之鹿林山為台灣背景空氣觀測站，預期長期監測此兩物種之濃度變化，以指示台灣因區域性大氣污染的長程傳輸所受到的衝擊程度。一氧化碳在大氣裡的生命期約一至三個月，具有足夠長的生命期，會隨著污染氣團的傳輸而移動，為一理想的污染氣團示蹤劑，但一氧化碳不單是生質燃燒的產物，凡有燃燒過程者皆會發生，如都會區大量汽機車內燃機的燃燒等，也為一氧化碳的重要來源。如前所述，台灣地區位於太平洋西側，鄰居於東南亞與大陸沿海地區，若僅監測一氧化碳，尚不足以鑑別台灣地區所觀測到的高濃度事件是為東南亞生質燃燒來源，抑或大陸沿海都市的排放，故於本計畫中提出以氟氯碳化物作為指紋氣體，一般生質燃燒並不會產生，氟氯碳化物幾乎為完全人造，在不同的地區及不同的環境下，有不同的排放程度，台灣因參與蒙特羅協議，政令禁止以致於氟氯碳化物濃度固定，較小的變異度顯示其排放量已極為稀微，但大陸地區現為開發中國家，並未完全限制其生產及使用，因此，觀測到氟氯碳化物的變異度與各物種間之比例關係，將不同於台灣地區本地來的源。本計畫中將利用此一關係，擬以在鹿林山背景站，同時對氟氯碳化物與一氧化碳進行長期連續觀測，追蹤污染物的來源，並評估台灣地區空氣品質所受到的衝擊。 ; In light of the complete lack of a systematic background observation in this geophysical region surrounding Taiwan, the impact of continental pollution on regional air quality surrounding Taiwan has not yet been fully assessed. The rapid economical growth in China and Asia as a whole in the last decade has aroused concerns on the increasing amount of anthropogenic particulate or gaseous pollutants transported to the Pacific, resulting in increased levels of pollutants in this geographic region. Situating on the brink of west Pacific Rim, Taiwan can serve as an ideal location for observing the change in concentrations and composition of air pollutants. As a result, a baseline station was established (Lulin Atmospheric Baseline Station; LABS) in the early 2006 and has been successfully running ever since. Carbon monoxide with a lifetime of about 3 months is an effective tracer of the outflow from China or biomass burning from Southeast Asia. Nevertheless, CO alone does not provide sufficient information to distinguish pollutions between different combustive origins. Consequently the purely anthropogenic CFCs have been recently added in the monitoring program at LABS, hoping to distinguish biomass and anthropogenic activities. Elevated concentrations of CO from the prevailing westerlies in spring due to bio-mass burning in Southeast Asia, or high levels of both CO and CFCs from the north-easterlies in fall are expected to pose a sharp contrast to their low levels in summer due to prevailing south-westerly marine air. Distinct diurnal and seasonal variations of CO and O3 have been noticed based on more than a year of continuous observation. Air masses of local and long-range-transport both affect the variation of CO and O3, with the former controlling the diurnal variation and the latter affecting the seasonal one. ; 研究期間 9708 ~ 9807
