李貞瑩－高雄都會區大氣環境中硫氧化物涵容能力之研究
Study of Atmospheric Carrying Capacity for Sulfur Oxides in Kaohsiung Metropolitan Area
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早期空氣污染管制以 命令式管制（ command and control） 為主，近幾年我國已將具經濟誘因之總量管制觀念納入空氣污染防制法中。根據環保署規劃，預計於民國 96年優先於高屏地區實施空氣污染總量管制制度。唯實施總量管制制度前，應先評估該地區之大氣涵容能力，瞭解達成空氣品質標準下所允許之空氣污染物排放總量。因此需透過空氣品質模式模擬空氣污染物之分布現況，並評估空氣污染物的涵容能力上限，以作為實施總量管制之污染物排放削減、抵換及交易之基準。
本研究以高雄市都會區為研究案例，並以目前美國環保署優選模式之ISCST3模式模擬SO 2 濃度之空間分布，並以模擬結果之背景濃度及現況濃度值，作為Rollback Model估算硫氧化物涵容能力之計算基準。另本研究建立之涵容能力估算方法及程序，將可作為未來實施總量管制參考。
高雄市及高雄縣SOx排放量主要以固定源為主，高雄市以小港區排放量約佔83.4﹪最高，行業別則以鋼鐵業佔44.7﹪為最高。模擬結果，高雄市SO2濃度最高值出現於小港區，主要受到該區內許多重大污染源聚集及位居下風處影響所致。SOx排放量第二高之楠梓區，因處上風區，使該區污染物擴散傳輸至其他地區，故楠梓區SO2濃度並不高。本研究另嘗試對高污染潛勢之中鋼、台電大林發電廠、中油高雄煉油廠及中油大林煉油廠進行排放量削減為現況之80﹪、70﹪及60﹪後，再以ISCST3模擬其濃度分布狀況，其模擬值與排放量之相關係數R 2 皆大於0.8，顯示排放量削減與濃度變化具有相當佳之關係，故要改善高雄市短期SO2之空氣品質惡化情形，可由固定源削減排放量著手。以Rollback Model估算高雄市都會區SOx之年涵容能力上限為94,208公噸，由於目前高雄市之年排放量為48,312公噸，低於涵容能力上限，顯示高雄市SOx仍有剩餘涵容量。
As opposed to the early days’ “command and control” policy, in recent years Taiwan has adopted the concept of total capacities to revise the air pollution control regulations; and the principles of total capacities incorporating with the economic incentives have been integrated into the revised Air pollution Control Law. The Environmental Protection Administration of Taiwan has promulgated that, in 2007, Kaohsiung-Pintung area will launch their air pollution control system based on its total capacity. However, prior to the implementation of this pilot plan, it is essential to assess the atmospheric carrying capacity of the region in order to decipher a permissible emission mount under the prescribed air quality standards. Therefore, it has become necessary to evaluate the distribution of the air pollutants with suitable air quality models, together with deciphering a cap in sustainable air pollutant capacities with which to provide a premise in emission reduction, offsetting and trading for executing of the total capacity control scheme.
This study focuses on the atmospheric SO2 concentrations in the greater Kaoshung metropolitan area, and heeds to the latest U.S. EPA selected ISCST3 for simulating the spatial distribution of SO2 concentration. The simulated background and the atmospheric SO2 concentrations are then used as the basis to calculate the carrying capacities of the SO2 using the Rollback method. In addition, the method and process used for calculation of the carrying capacity reported in this study should be useful for future studies.
The major emission of SOx throughout the Kaohsiung area was from the stationary sources, and 83.4% of the SOx emissions were from Shiao-gang District of Kaohsiung City. Among the various industries, 44.7% of the total SOx emissions were from the steel industry. The model simulations concluded that the highest SO2 concentration was obtained in the Shiao-gang District of Kaohsiung City due to the large congregation of the major emission sources and Shiao-gang is located in the downdraft area. Coming in second was the Nan-tze District with a moderate SO2 concentration due to its updraft position that had had its pollutants diffused to the other areas. Based on the calculation of ISCST3 model, the emissions from major industries including China Petrochemical Corporation, Taiwan Power Company’s Dalin power plant, CPC’s Kaohsiung Refineries and CPC’s Dalin Refineries were cut down to 80%, 70% and 60% of the original settings to simulate the impact on the spatial distribution of SO2 concentration. The results revealed that there is a fairly good correlation between the emissions and atmospheric concentrations of SO2 (with R2 > 0.8). This observation indicated that reduction on the SOx emission at the stationary sources could provide a viable means in reducing the deteriorating SOx in the greater Kaohsiung area. When the chemical reaction, dry and wet depositions and the long-range transport of the SOx were not considered, the Rollback Method concluded that the annual carrying capacity of the SOx in the Kaohsiung metropolitan area was 461,862 tons. The current annual emission in Kaohsiung City (48,312 tons) is lower than the calculated carrying capacity.