碳氫化合物組合與近地面臭氧生成

The Composition of Non-Methane Hydro-Carbon and the Surface Ozone Production

柳中明(C. M. Liu) ； 蔡育文(Y. W. Tsay) ； 左台利(T. L. Tso) ； 羅俊光(G. K. Lo) ； 劉紹臣(Shaw C. Liu)

《大氣科學》 22卷3期 (1994/09) Pp. 431-453

摘要

本文主要希望尋找台北地區清晨6~9時間，空氣中非甲烷碳氫化合物的組成。並期望探究碳氫化合物初始組成對近地面臭氧生成的潛在影響。研究中採用清華大學研究群在1991年所收集到的資料，再經嚴謹的討論、分析、整理與組合，獲得適合光化模式使用的初始NMHC組成。然後比較台北、洛杉磯（LA）、與ADMP（美國區域酸雨沈降模式）等三類不同初始NMHC組合，經光化模式模擬，所獲得午時最高臭氧濃度的差別。台北組成中由於包含比較多的正反2丁烯成份，以致化學反應活性為LA的1.6倍，為ADMP的2.8倍，所以午時所生成累積的臭氧濃度明顯為多。在與實測值比較上，因為所使用的箱型模式未考慮垂直擴散、水平傳送與污染物持續輸入等因素，所以模擬值與實測值有相當差異。不過，重要的是：不同的NMHC初始組成，對臭氧生成確實有極大的影響，此為本文研究重點。本文拋磚引玉，希望未來國內能對人為排放與自然界排放的揮發性碳氫化合物成份，與NMHC/NOx比例，能有更深入與廣泛的觀測數據。本文另外也探究本地高水汽含量對臭氧生成的影響，結果才約造成至多10%的臭氧量增加，且在高污染地區影響不大，對低污染地區影響較大。未來，吾人將進一步分析本地高懸浮微粒的污染現象，所造成的近地面紫外射線減少，對臭氧生成的影響。

關鍵字

臭氧生成 ； NMHC組成

並列摘要

This paper intends to find out the composition of non-methane hydrocarbon (NMHC) in the early morning (6-9am) in Taipei, and to study the effect of NMHC composition on the surface ozone production. The observational data collected by the research group in the National Tsin-Hwa University has been thoroughly analyzed and re-organized to produce the Taipei composition. By using a box chemical model, we have then compared the noontime ozone amount simulated with different initial NMHC composition, i.e. the Taipei, or Los Angeles (LA) or ADMP (Acid Deposition Modeling Program) composition. Since there are more trans-2-butene in the Taipei composition, its reactivity is about 1.6 times that of LA, and 2.8 times that of ADMP. Our results suggest that the ozone productivity is positively correlated to the reactivity of NMHC composition. Since the model that used in this study does not allow vertical diffusion, horizontal advection and continuous input of pollutants. The simulated result differs a little from the observed value.This research is very primitive and needs further pursued. We hope that more studies will be done in the future to analyze the anthropogenic and natural emitted NMHC and to determine more precisely the ratio of NMHC/NOx. In this paper, we have also analyzed the effect of abundant water vapor on the productivity of ozone. The results show that a maximum of 10% enhancement by a change of 30% to 70% relative humidity. Such enhancement is actually not significant at all in a highly polluted area. In the future, we will study the effect of UV depletion caused by the aerosol backscattering on the surface ozone.

並列關鍵字

Ozone Production ； NMHC composition