EPA-94-FA11-03-A225

094

1,980 千元

2005/09/20

2006/02/28

詹長權

空保處

國立台灣大學職業醫學與工業衛生研究

化學物質管理

光化學現象,臭氧前驅物,健康效應

Photochemical reaction,ozone precursor,health effect

王家麟

蔡黛華

02-23222363

d93841002@ntu.edu.tw

本研究利用環保署光化學測站在台灣中部空品區之崇倫測站、草屯測站及竹山測站從2002年至2005年的資料進行探討，研究目標包括：一、以光化測站觀測資料及模式模擬分析光化模式之化學場、氣團來源、臭氧事件日與非事件日，兩大類臭氧前趨物(VOCs及NOx)在光化作用與氣象條件上之相關性。二、探討中部與南部地區臭氧成因、傳輸機制與其控制因素。三、評估光化測站之揮發性有機化合物濃度對台灣地區居民健康之影響。研究發現中部地區的汙染物濃度的日夜變化主要受到海陸風的控制，通常在日間逆溫被日照破壞而引進海風，到午時風速到達最大值，此時一次汙染物濃度不易累積；而日落後至清晨時段為風速極低的陸風，若再加低逆溫層的出現則容易造成早晨高汙染情形的出現。在秋季因逆溫容易在夜間或清晨形成，往往導致空氣垂直混合不良，提高前驅物濃度，也儲備足夠的VOC作為光化的原料。南投地區於夏季之VOC/NOx比值穩定，明顯屬於VOC控制的條件；秋季時的氣象條件使得VOC/NOx比值在白天產生劇烈變化，造成不同於夏季的VOC控制條件。在台中市進行主成份分析發現大部份56種VOC都是由移動源所貢獻，少部份物質如乙烷、丙烷、及部份丁烷則由瓦斯洩漏所貢獻，溶劑揮發僅限於toluene單一物種，因此更証明中部地區的光化前驅物和移動源有密切關聯。健康效應方面，本研究截取2002年至2004年光化測站之正已烷、苯、甲苯、乙苯、間,對-二甲苯、苯乙烯、鄰-二甲苯及丙烯濃度資料與空品測站之PM10、NO2、SO2、CO、O3污染物濃度資料，其濃度分佈的趨勢，均呈現台中市高於南投縣。另外，結合死亡率資料來看，台中市之全自然死因年標準死亡率(千人率:31.9 ~ 32.5)高於南投縣(千人率: 31.6 ~ 31.0)，癌症標準死亡率亦同，此一趨勢與濃度的分佈趨勢是相同的。本研究成果已符合計畫之第一年研究目標，第二年除了要在南部光化測站建立風險背景值之外，亦進一步探討光化測站之污染物濃度值與癌症發生率與死亡率之關係。

光化學現象,臭氧前驅物,健康效應

EPA94FA1103A225.pdf

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[期末報告]公開完整版

2006/7/1 上午 12:00:00

The concentration of air pollutants were most likely affected by the land-sea breeze in central Taiwan. The mixing height is elevated by the westerly winds, which reach maximum values near noontime resulting in dissipation of pollutants. By contrast, the slower wind speeds in nighttime facilitate the build-up of ozone precursors. The formation of inversion layers at night is more pronounced in autumn than in summer rendering poorer vertical mixing and, hence, higher concentrations of precursors as well as ozone. In summer, the ratio of VOC/NOx is stable and it is more likely to fit in the characteristics of VOC-limited condition. In contrast, the ratio becomes more variable in fall, which is presumably induced by the unique meteorology associated with the fall season in central Taiwan. This instability in ratio in fall may partially explain the incoherence between ethylbenzene/xylene ratios and daily ozone peak values. This study also found that the majority of 56 target VOCs are released from motor vehicles. A second group of compounds, such as ethane, propane, and butane are originated from the leakage of liquefied petroleum gas (LPG) and natural gas. This study also investigated whether the some specific VOCs affect mortality. We combined continuous hourly data from PAM stations from 2002 to 2004 and also collected census and death data from governmental organizations. The results showed the the total natural mortality and cancer mortality in Taichung city were higher than in Nantou County, and this trend was similar with the concentration trend. Since the concentration is not as high as in occupational area, the long-term concentration data of these VOCs are recommended to be collected continuously in the future.

Photochemical reaction,ozone precursor,health effect