短期臭氧暴露對呼出氣體中揮發性有機物影響之探討

Abstract

本研究之目的為比較抽菸與非抽菸之健康受試者暴露臭氧前後呼出氣體中揮發性有機物的差異，觀察抽菸與非抽菸者對暴露臭氧反應之不同，並利用呼氣中pentane作為氧化壓力指標探討暴露臭氧前後體內之氧化壓力變化情形。 本實驗為縱向研究法，共收集20位受試者，分別為抽菸者8位、非抽菸者12位，年齡介於20~30歲間。利用口罩暴露系統於每日早上九點至十二點間暴露100 ppb 臭氧兩個小時，利用採樣袋收集受試者暴露前、暴露後5分鐘、30分鐘、4.5時及22小時之呼出氣體，再以定流量將呼氣中揮發性有機物採集至採樣管中，總採樣體積為1公升，之後用熱脫附法搭配氣相層析質譜儀進行分析，所得結果扣除干擾物質後與現有圖譜資料庫直接比對共定性出117種化合物，並採用半定量方式來定量。 實驗結果顯示抽菸者暴露臭氧後隔天呼氣中戊烷含量較暴露前高，達邊緣性顯著，非抽菸者則無。非抽菸者呼氣中含硫化物如二甲基硫化物和二甲基二硫化物皆在暴露臭氧後短時間內顯著增加，暴露後隔天則恢復至和暴露前相近；抽菸者則是在暴露後短時間內無顯著差異但暴露後隔天呼氣中含量顯著高於暴露前。推測抽菸者為臭氧暴露之易感族群且恢復能力較非抽菸者差。比較抽菸者與非抽菸者暴露前之呼出氣體發現有17種物質在兩組間達顯著差異且其在抽菸者呼氣中濃度於暴露臭氧後短時間內皆顯著下降，停止暴露後逐漸回復原本濃度。

The purposes of this study were to investigate the effect of controlled ozone exposure for smokers and nonsmokers on the exhaled volatile organic compounds (VOCs), to compare the responses of ozone exposure between the two groups, and to evaluate whether exposure to ozone induced changes in exhaled pentane, which serve as a biomarker of oxidative stress. This study was a longitudinal study. Twenty volunteers (eight smokers and twelve nonsmokers),ages ranging from 20 to 30 years old, were exposed to 100 ppb of ozone for 2 hours. Subjects were exposed to ozone via a face-mask inhalation system between 9:00 am and 12:00 am. Tedlar sampling bags were used to collect exhaled air before and after exposure at 5 minutes, 30 minutes, 4.5 hours and 22 hours. One liter of exhaled air in the sampling bags then was withdrawn by a sampling pump, and the VOCs in the exhaled air was collected using multi-bed sorbent traps and analyzed by Gas Chromatography/Mass Spectrometry. One hundred and seventeen VOCs were identified by a mass spectra library and were semiquantitatively analyzed. Exhaled pentane level in smokers but not in nonsmokers, were increased 22 hours after ozone exposure. The level of exhaled sulphur-containing compounds thiobismethane and dimethyldisulfide in nonsmokers were immediately increased following ozone exposure whilst in smokers the levels were increased only after 22 hours of ozone exposur. We suggested that smokers were more sensitive to ozone exposure than nonsmokers. Comparing the exhaled air VOCs from smokers and nonsmokers before ozone exposure, 17 compounds were significantly different between the two groups.