EPA-96-L105-02-201

096

1,840 千元

2007/03/08

2007/12/31

鄭福田

監資處

孫意惇

台大嚴慶齡工業研究中心

環境資訊系統

臭氧,箱型模式,敏感性物種

ozone,box,model,carbonyl

林文印,劉遵賢

r94541107@ntu.edu.tw

台灣地區的指標污染物中，臭氧是造成空氣品質不良的主要污染物之一，根據環保署資料顯示，台灣地區的臭氧平均濃度有上升的趨勢。對臭氧的問題，雖然有臭氧前驅物與臭氧本身的觀測資料，但對屬於光化學二次污染物觀測資料則仍顯不足，因此透過台北都會區二次光化污染物監測，建立長期基本資料，將有助於對臭氧問題的成因分析。 萬里及與那國島等大氣背景測站資料顯示，台北都會區的臭氧背景狀況並無明顯的變化，台北都會區中各空品測站之臭氧年平均濃度則有顯著的增加，但從總氧化物的變化不如臭氧上升幅度，氮氧化物與臭氧亦大多呈現負相關，顯示氮氧化物對臭氧有一定的滴定效應存在。 二次光化污染的長期變化趨勢，本計畫發現醛酮化合物的濃度分佈與盛行風向相關；而由歷史資料分析，亦發現土城地區主要盛行風向為東風系，但高臭氧則大多出現在風向為西風系時，顯示風向為影響臭氧及醛酮濃度的因子之一。 本計畫利用光化學箱型模式模擬臭氧濃度的變化，模擬結果顯示，模式能有效模擬各污染物的初期變化。藉由此模擬結果，利用烷類、烯類、芳香族類及醛酮類等污染物的初始濃度變化，瞭解臭氧主要敏感性物種，模擬結果顯示，在2007年5月3日案例中，芳香族類及醛酮類為主要致臭氧生成物種，2007年7月5日案例中，主要致臭氧生成物種則為芳香族類及烷類。

臭氧,箱型模式,敏感性物種

期末報告.rar

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[期末報告]公開完整版

2008/3/1 上午 12:00:00

Ozone is one of the most important ambient tracers that caused severe problem of air pollution in Taiwan. In this project, the issues of long-term trend of ozone variation and short-term mechanism of ozone episode were explored. In order to study these two problems, long-term monitoring results from Taiwan EPA ambient monitoring stations in Taipei metropolitan region were collected for further analysis the trend of ozone variations. In addition, air samples in Tuchen Station and Shitzi Station were also collected to analyze the concentration levels of some secondary photochemical air pollutants. Our results showed that there is no obvious trend of the background ozone concentration level found according to the long-term data of Wanli Station, which is supposed to be the background ambient station of northern Taiwan. This result was confirmed by the ozone data obtained from the Yonagunijima Station of World Data Centre for Greenhouse Gases (WDCGG). On the other hand, the annual averaged ozone concentration of most Taipei metropolitan showed obvious ascending trends. However, the trends of total oxidants (Ozone+NO2) were minor for most stations. In addition, there are obvious negative correlation between ozone and NOx. It is concluded that the ascending trends of ozone concentration level were mainly caused by the descending NOx because the titration effect of NO to ozone. The effect of background ozone was very minor. Observation of secondary photochemical air pollutants showed that the concentration level of carbonyl could be accounted by the wind direction. When the wind came from west (including northeast and southwest), there was more possibility to observe higher carbonyl concentration. When the wind came from east (including northeast and southeast), the concentration level of carbonyl was always low. Analysis of the long-term wind rose data also showed that the higher ozone periods usually happened in west wind while the prevailing wind in Tuchen Station was from east. It is concluded that there was much more possibility of high ozone for west wind than east. The "Taiwan Air Quality Model" (TAQM) was applied in this study to explore the two high ozone episodes happened in May 3rd, 2007 and May 7th, 2007. The simulation results showed that surface ozone concentration in western corridor of Taiwan was largely influence by local emission and background ozone concentration for the first episode (May 3rd). The influence of long-range transported pollution is very minor. However, it is another case for the second episode (May 7th). Ozone is largely influenced by long-range transport while local emission and background still played important roles. We further explored the contribution of chemical species with the help of photochemical box model. Model results showed that aromatics and carbonyl are the two most important classes of chemical species that accounted for the high ozone in the first episode.

ozone,box,model,carbonyl