環保專案成果報告查詢系統

專案計畫編號	EPA-96-FA11-03-D059
經費年度	096
計畫經費	2,800 千元
專案開始日期	2007/05/15
專案結束日期	2007/12/31
專案主持人	吳義林
主辦單位	空保處
承辦人	陳婉菁
執行單位	財團法人成大發展基金會
專案分類	化學物質管理
中文關鍵字	海陸風、內邊界層、臭氧滯留層、臭氧消耗層、逆軌跡分析
英文關鍵字	sea-land breeze, internal boundary layer, ozone residence layer, ozone depletion
協同主持人	林清和、賴進興、賴信志、林博雄、蔡德明
共同主持人
計畫聯絡人
計畫聯絡電話
計畫聯絡信箱	niki@pc510.ev.ncku.edu.tw

中文摘要	本計畫之目標為針對山谷風及海陸風之三維氣象與空氣品質觀測數據，並結合氣象與空氣品質模式，探討高屏地區山谷風及海陸風特性與其對於空氣污染物傳輸之影響，並完成綜合所有實際高空觀測數據與模式模擬之分析，解析高屏地區局部環流與空氣污染之關係，探討高屏地區嚴重空氣污染之成因，以研擬該地區未來空氣污染之防制策略。高屏空品區之氣象場特性顯示海陸風非常顯著，因而垂直剖面之風場明顯具有三層，第一層由地面至900-1200 m，多為偏西之氣流，可能是海風所造成，第二層位於第一層高度以上至2400-3000 m 間，風向可能為偏南、偏東或偏北，可能與中央山脈有關，第三層位於第二層以上，明顯屬於西風帶的範圍。故高屏空品區受海陸風與山谷風環流及地形之繞流與尾流渦漩的綜合作用。氣流繞流的效應會將台灣北部、中部的污染物帶進高屏地區，然而由於位於尾流區的關係，被帶進或局地排放之空氣污染物並不容易被傳輸到高屏以外的區域，而造成高屏地區高空氣污染的現象。也就是說，台灣的地形與氣候的交互作用結果，對空氣品質而言，會使得高屏地區的氣象條件是容易受到區域外傳輸累積而產生不良的結果，這種情形也不利大型排放源在本區設置。空氣品質之長期變化趨勢分析結果顯示除了屏東測站外，其餘各測站之臭氧濃度均呈上升的趨勢，其中以美濃、林園與前金等三站之上昇趨勢較為明顯，平均每年上升量為0.5-1.1 ppb。但是臭氧前驅物氮氧化物及非甲烷碳氫化合物濃度均呈下降的趨勢，平均每年下降量分別為0.5-1.8 ppb 與2-14 ppbC。而斗六站、台南站之紫外線強度有逐年上升之現象，增加的比例分別為每年0.55％、0.43％，但是屏東站之紫外線則是為下降而其比例為每年-0.41％，故紫外線強度的增加為造成臭氧濃度上升的原因之一。綜合觀測與模擬結果顯示臭氧濃度之垂直剖面分佈可歸類為四型：日間於內陸地區之均勻混合型與近海岸地區的內部邊界層作用型及夜間之臭氧滯留層型與受點源影響之臭氧消耗層型。而且臭氧滯留層對當日地面臭氧濃度之影響平均值為5～12ppb，而影響較大之測站依序為屏東站、潮州站、美濃站與大寮站。由三維逆軌跡分析高屏空品區之臭氧不良空氣品質事件的軌跡，結果顯示無迴流之跨空品區傳輸的比例僅為14％，而跨雲嘉南與高屏空品區之迴流軌跡的事件日比例為26％，主要之比例均是為於高屏空品區內之迴流逆軌跡，其比率為60 ％，故高屏空品區之排放源為造成臭氧空氣品質不良之主要污染源。另外，比較分析結果顯示二維與三維逆軌跡之相似比例甚低，全部之比例僅為18％。綜合光化指標分析結果顯示接近污染源之工業區與都會區下風處為VOCs 控制，而老化氣團之較偏遠地區為NOx 控制為至，故高屏空品區NOx 與NMHC 仍應持續控制降低。另外，建議在小琉球建立一空氣品質測站；以三維逆軌跡分析高屏空品區之源與受體關係；更新近幾年之資料以進行量化分析長程傳輸作用，氣候變化造成光化強度之上升，非甲烷碳氫化合物之物種成份改變及近幾年之排放量改變的個別影響；由於高屏區之垂直氣象場十分複雜，應更多實地高空觀測與模式模擬之比對，建立預測高污染日之機制，並且應用光化指標之實際關測結果以決定臭氧控制之前驅物。
中文關鍵字	海陸風、內邊界層、臭氧滯留層、臭氧消耗層、逆軌跡分析

中文摘要

本計畫之目標為針對山谷風及海陸風之三維氣象與空氣品質觀測數據，並結合氣象與空氣品質模式，探討高屏地區山谷風及海陸風特性與其對於空氣污染物傳輸之影響，並完成綜合所有實際高空觀測數據與模式模擬之分析，解析高屏地區局部環流與空氣污染之關係，探討高屏地區嚴重空氣污染之成因，以研擬該地區未來空氣污染之防制策略。高屏空品區之氣象場特性顯示海陸風非常顯著，因而垂直剖面之風場明顯具有三層，第一層由地面至900-1200 m，多為偏西之氣流，可能是海風所造成，第二層位於第一層高度以上至2400-3000 m 間，風向可能為偏南、偏東或偏北，可能與中央山脈有關，第三層位於第二層以上，明顯屬於西風帶的範圍。故高屏空品區受海陸風與山谷風環流及地形之繞流與尾流渦漩的綜合作用。氣流繞流的效應會將台灣北部、中部的污染物帶進高屏地區，然而由於位於尾流區的關係，被帶進或局地排放之空氣污染物並不容易被傳輸到高屏以外的區域，而造成高屏地區高空氣污染的現象。也就是說，台灣的地形與氣候的交互作用結果，對空氣品質而言，會使得高屏地區的氣象條件是容易受到區域外傳輸累積而產生不良的結果，這種情形也不利大型排放源在本區設置。空氣品質之長期變化趨勢分析結果顯示除了屏東測站外，其餘各測站之臭氧濃度均呈上升的趨勢，其中以美濃、林園與前金等三站之上昇趨勢較為明顯，平均每年上升量為0.5-1.1 ppb。但是臭氧前驅物氮氧化物及非甲烷碳氫化合物濃度均呈下降的趨勢，平均每年下降量分別為0.5-1.8 ppb 與2-14 ppbC。而斗六站、台南站之紫外線強度有逐年上升之現象，增加的比例分別為每年0.55％、0.43％，但是屏東站之紫外線則是為下降而其比例為每年-0.41％，故紫外線強度的增加為造成臭氧濃度上升的原因之一。綜合觀測與模擬結果顯示臭氧濃度之垂直剖面分佈可歸類為四型：日間於內陸地區之均勻混合型與近海岸地區的內部邊界層作用型及夜間之臭氧滯留層型與受點源影響之臭氧消耗層型。而且臭氧滯留層對當日地面臭氧濃度之影響平均值為5～12ppb，而影響較大之測站依序為屏東站、潮州站、美濃站與大寮站。由三維逆軌跡分析高屏空品區之臭氧不良空氣品質事件的軌跡，結果顯示無迴流之跨空品區傳輸的比例僅為14％，而跨雲嘉南與高屏空品區之迴流軌跡的事件日比例為26％，主要之比例均是為於高屏空品區內之迴流逆軌跡，其比率為60 ％，故高屏空品區之排放源為造成臭氧空氣品質不良之主要污染源。另外，比較分析結果顯示二維與三維逆軌跡之相似比例甚低，全部之比例僅為18％。綜合光化指標分析結果顯示接近污染源之工業區與都會區下風處為VOCs 控制，而老化氣團之較偏遠地區為NOx 控制為至，故高屏空品區NOx 與NMHC 仍應持續控制降低。另外，建議在小琉球建立一空氣品質測站；以三維逆軌跡分析高屏空品區之源與受體關係；更新近幾年之資料以進行量化分析長程傳輸作用，氣候變化造成光化強度之上升，非甲烷碳氫化合物之物種成份改變及近幾年之排放量改變的個別影響；由於高屏區之垂直氣象場十分複雜，應更多實地高空觀測與模式模擬之比對，建立預測高污染日之機制，並且應用光化指標之實際關測結果以決定臭氧控制之前驅物。

中文關鍵字

海陸風、內邊界層、臭氧滯留層、臭氧消耗層、逆軌跡分析

類型	檔名	檔案大小	說明	最新版公開日期
期末報告	EPA-96-FA11-03-D059.pdf	40MB	[期末報告]公開完整版	2008/5/1 上午 12:00:00

摘要	The purposes of this study are to evaluate the effects of local circulations on the ambient air quality and to study the control strategies for ozone in southern Taiwan. The characteristics of local circulations were studies by three-dimensional field observations and model simulations. Sea-land breeze and valley wind dominate the local circulation in southern Taiwan. Therefore, the vertical profile of wind field can be divided into three regions: the first region is from ground to 1200 m which is dominant by the local circulations, the second region is above the first one to 3000 m which is determined by the vortex eddy due to the effect of topography on seasonal northeastern wind, and the third and highest region is the prevailing western wind. Thus, the combined effect of local circulations and vortex eddy forms a convergent region around Kaoping area and air pollutants cumulate in this region to create bad air quality. The long-term trend analysis for the EPA monitored data showed that the ozone concentration increased at rates of 0.5 to 1.1 ppb per year, except for Pingtung station. However, the concentrations of NOx and NMHC, ozone precursors, decreased at rates of 0.5 to 1.8 ppb and 2 to 14 ppbC per year, respectively. The intensities of UVb at Douliu and Tainan stations increased gradually at rates of 0.55% and 0.43% per year, respectively; but those at Pingtung station decreased at rate of 0.41% per year. Therefore, the variations of ozone concentrations were highly correlated with those of UVb intensities; the increment of solar intensity may be one of the reasons causing the high ozone concentrations. The diurnal variations of vertical profiles of ozone concentrations can be classified into four groups based on the results of field observations and model simulations. The four types are the uniform vertical profile at inland region and the internal boundary layer at coastal region during daytime and the ozone residence layer and the ozone depletion layer at nighttime. The contributions of ozone residence layer on the ground ozone concentrations are on the average of 5 to 12 ppb and the peak hourly value is up to almost 30 ppb. Three-dimensional back trajectory analysis is conducted to evaluate the source and receptor relationship for each ozone episode event by using the MM5 simulation results. The back trajectory analyses show that the fractions of no circulated cross air basin transport, circulated flow cross Kaoping and Yuchianan air basins, and circulated flow within Kaoping air basin only are 14%, 26%, and 60%, respectively. Therefore, the ozone events in Kaoping air basin are predominantly due to its own emission. The sensitivity analyses for ozone control show site dependent results: VOCs-control at near downwind sites of urban and industry parks and NOx-control for aged air parcel at remote area. Therefore, emission for both NOx and NMHC should be reduced in order to control the ozone concentrations in Kaoping air basin. The suggestions of this projects include to setup an air quality monitoring site at Shinliuchow, to use three-dimensional back trajectory analysis to study the source and receptor relationship, to further analyze the causes for the increasing ozone concentration and to conduct more three dimensional field observation due to the complex air flow patterns in southern Taiwan.
英文關鍵字	sea-land breeze, internal boundary layer, ozone residence layer, ozone depletion

摘要

The purposes of this study are to evaluate the effects of local circulations on the ambient air quality and to study the control strategies for ozone in southern Taiwan. The characteristics of local circulations were studies by three-dimensional field observations and model simulations. Sea-land breeze and valley wind dominate the local circulation in southern Taiwan. Therefore, the vertical profile of wind field can be divided into three regions: the first region is from ground to 1200 m which is dominant by the local circulations, the second region is above the first one to 3000 m which is determined by the vortex eddy due to the effect of topography on seasonal northeastern wind, and the third and highest region is the prevailing western wind. Thus, the combined effect of local circulations and vortex eddy forms a convergent region around Kaoping area and air pollutants cumulate in this region to create bad air quality. The long-term trend analysis for the EPA monitored data showed that the ozone concentration increased at rates of 0.5 to 1.1 ppb per year, except for Pingtung station. However, the concentrations of NOx and NMHC, ozone precursors, decreased at rates of 0.5 to 1.8 ppb and 2 to 14 ppbC per year, respectively. The intensities of UVb at Douliu and Tainan stations increased gradually at rates of 0.55% and 0.43% per year, respectively; but those at Pingtung station decreased at rate of 0.41% per year. Therefore, the variations of ozone concentrations were highly correlated with those of UVb intensities; the increment of solar intensity may be one of the reasons causing the high ozone concentrations. The diurnal variations of vertical profiles of ozone concentrations can be classified into four groups based on the results of field observations and model simulations. The four types are the uniform vertical profile at inland region and the internal boundary layer at coastal region during daytime and the ozone residence layer and the ozone depletion layer at nighttime. The contributions of ozone residence layer on the ground ozone concentrations are on the average of 5 to 12 ppb and the peak hourly value is up to almost 30 ppb. Three-dimensional back trajectory analysis is conducted to evaluate the source and receptor relationship for each ozone episode event by using the MM5 simulation results. The back trajectory analyses show that the fractions of no circulated cross air basin transport, circulated flow cross Kaoping and Yuchianan air basins, and circulated flow within Kaoping air basin only are 14%, 26%, and 60%, respectively. Therefore, the ozone events in Kaoping air basin are predominantly due to its own emission. The sensitivity analyses for ozone control show site dependent results: VOCs-control at near downwind sites of urban and industry parks and NOx-control for aged air parcel at remote area. Therefore, emission for both NOx and NMHC should be reduced in order to control the ozone concentrations in Kaoping air basin. The suggestions of this projects include to setup an air quality monitoring site at Shinliuchow, to use three-dimensional back trajectory analysis to study the source and receptor relationship, to further analyze the causes for the increasing ozone concentration and to conduct more three dimensional field observation due to the complex air flow patterns in southern Taiwan.

英文關鍵字

sea-land breeze, internal boundary layer, ozone residence layer, ozone depletion