EPA-92-U1L1-02-105

092

1,350 千元

2003/06/12

2003/12/31

王根樹

監資處

台灣大學公共衛生系

環境資訊系統

數值模式,光化學評估測站,揮發性有機物,臭氧

ozone,Photochemical Assessment Monitoring Station,VOCs,model

張艮輝

王根樹

02-23940612

gswang@ha.mc.ntu.edu.tw

近幾年來之空氣品質監測資料顯示臭氧與懸浮微粒為台灣地區二個主要空氣污染物，其中都會地區之臭氧並有日益嚴重之趨勢。為確認這種趨勢，環保署監資處相繼於主要都會區設置光化學評估測站(Photochemical Assessment Monitoring Station, PAMS)，以全面掌握全台灣主要光化學污染區域之污染特徵。光化學評估測站收集了許多非常重要之觀測資料，如逐時揮發性有機物(VOCs)成份資料等，這些資料對於解釋臭氧等光化學污染現象之成因與可能之污染來源，將提供非常可觀之直接證據。 本計畫分析光化測站逐時監測濃度，探討VOCs濃度與下風處臭氧事件之關聯性；並以高解析度之空氣品質模式，分析掌握台灣地區整體臭氧污染之時間與空間上之分布特徵，並透過與光化學評估測站觀測資料之比較驗證，分析研究O3污染重點區域之光化污染潛在成因，以了解排放源、地理地形、及氣象等因素在O3污染事件中所扮演之角色與相對重要性。本計畫主要工作項目包括化學評估測站監測數據與數值模擬比較分析、光化學污染之時空分布與前驅物之相關性分析、提供光化學評估測站監測數據應用與解析之建議、提供空氣品質預報之建議等。 研究結果顯示，光化站濃度最高的幾種VOCs是Toluene、iso-Butene、Ethane、Propane、Ethene、iso-prene、Acetylene、n-Butane等物種；其中Toluene及iso-Butene之濃度又顯著高於其他物種。在分析90年及91年三義、苗栗、二林、彰化、南投及竹山測站之臭氧事件日，均可觀察到前述VOCs物種之濃度曲線在臭氧達到高峰前的數小時，會有先上升再下降的的情形，且各VOC濃度出現高峰的時間大致相同。然而臭氧生成是一個非常複雜的光化學反應，依據幾次臭氧事件日或高臭氧濃度（>100 ppb）時之分析結果，即使當時之氣象條件符合臭氧生成之條件，但崇倫站之VOC濃度未必較高；同理，即使崇倫站之VOC濃度高且當時之氣象條件符合，下風處臭氧濃度未必高。此種現象顯示僅依據上風處VOC濃度及氣象條件尚不足以評估下風處臭氧濃度是否上升；必須進一步考慮氮氧化物之效應。在評估臭氧事件時，必須同時考慮VOC濃度及氮氧化物之濃度，且氣候條件必須適合，方能有效判斷臭氧事件發生之可行性。

數值模式,光化學評估測站,揮發性有機物,臭氧

0000033721.pdf

4MB

[期末報告]公開完整版

2004/3/1 上午 12:00:00

In general, ozone will be formed in suburban area or downstream of industrial area due to the transport and reactions of the air pollutants. The entire environmental conditions are quite complicated and it is difficult to identify the environmental condition that ozone is formed. However, the developments of high resolution photochemical model which include the physical-chemical parameters like photochemical reactions, transport, precipitations and emission will be helpful to verify the sources and reactions of ozone pollution. In this study, a high resolution air quality model will be used to study the characteristics of the temporal and spatial ozone distribution in Taiwan. The concentrations of the ozone precursors obtained by the PAMS will be compared to evaluate the photochemical reactions in areas with high ozone concentrations. The roles of sources, geographic factors and meteorological conditions in ozone pollution will be studied. Specific objectives of this study are: (1)to conduct data analysis and model simulations on VOCs data obtained from PAMS. (2)to study the correlations between the VOCs data and the ozone episodes. (3)to evaluate the potential applications and interpretations of the air quality data obtained from PAMS. (4)to provide recommendations for the air quality predictions. The results revealed that the most important VOCs observed are Toluene、iso-Butene、Ethane、Propane、Ethene、iso-prene、Acetylene and n-Butane. In general, the ozone concentration increases several hours after the VOCs concentrations in PANS reach their maximum concentrations. However, the photochemical process is a highly complicated reaction. Although higher VOC concentrations may favor the ozone formation, several cases demonstrated that ozone episodes may be observed even when the concentrations of VOCs in PAMS are low. It is essential to monitor both the concentrations of VOCs and NOx, and the meteorological conditions should be evaluated for possible predictions of ozone episodes.

ozone,Photochemical Assessment Monitoring Station,VOCs,model