| 摘要: | 本研究選擇台中市數個地點,如學校附近、市區交通頻繁區、效區、工業區,針對空氣中揮發性有機物進行調查研究。使用的採樣管充填Carbopack B吸附劑,以熱脫附氣相質譜儀進行定性及定量分析,並參考USEPA TO-17方法中的採樣及分析步驟,建立本研究之適用方法。 分析測試結果發現:熱脫附儀的脫附效率可達98%,分析物重複測試七次的精密性,其變異數皆小於10%,樣本置於內含活性碳及乾燥劑玻璃瓶在 4.degree.C冰箱儲存至少可保存二週,經現場測試後採樣的安全採樣體積訂定為16L。 本研究監測結果台中市空氣中揮發性有機物以甲苯濃度最高為141.4.mu.g/m/sup 3/,苯為人類致癌性物質其濃度為39.4.mu.g/m/sup 3/,在台中市各採樣點以中正路商業區空氣中揮發性有機物濃度最高,日濃度變化呈現雙峰之型態,而且白天比夜間濃度為高,假日濃度比工作日濃度高。室內空氣採樣也是甲苯濃度最高為123.7.mu.g/m/sup 3/,苯濃度為18.9.mu.g/m/sup 3/,室外濃度比室內高。 本研究並探討在不同時段與區段空氣中揮發性有機物與機汽車流量PSI測值及氣象資料之相關性,發現機汽車流量與VOCs濃度的相關性很強。另外利用監測結果推估上班族一生的因苯而致癌的危險率為7.9*10/sup -7/。
This study was investigating of volatile organic compounds in ambient air around areas of different categories in Taichung city. A sampling unit was consisting of a sample tube packed with Carbopack B as adsorbent. By using the thermal desorption technique in conjunction with gas chromatography/mass spectrometry, the qualitative and quantitative analyses of volatile organic compounds was studied. USEPA TO-17 method was applied throughout this study. The optimum analytical parameters were then established. The desorption efficiencies of target compounds were all above 97%. The coefficient of variance (CV%) of seven replicated standard gas samples was less than 10%. The glass bottle containing activated charcoal and desiccant agent was applied for sample storage and two weeks period of time can be extended. The safe sampling volume of 16L was determined from field test. Results showed that toluene was the most abundant spices of VOCs investigated outdoor in Taichung city with concentration of 141.4.mu.g/m/sup 3/. The average concentration of benzene, the confirmed human carcinogen, was 39.4.mu.g/m/sup 3/. The highest concentration of VOCs was found around area of Chung Cheng Road which is classified as business section. The variation trend of VOCs concentration in the course of this investigation exhibited a binominal pattern on daily base. It showed that concentration at daytime was higher than that in the evening and the concentration on holidays were higher than that on working days. For indoor air investigation, the concentration of toluene was also found to be the highest at averaged value of 123.7.mu.g/m/sup 3/ and yet, the concentration of benzene was 18.9.mu.g/m/sup 3/. The outdoor concentration of VOCs was higher than that of indoor air. The correlation between factors in terms of concentrations of VOCs, number of motor vehicles passing by, pollutant standard index (PSI) readings as well as climate conditions (i.e. wind direction, wind speed, temperature, humidity, barometric pressure etc.) was investigated. Among these factors, the number of motor vehicles correlated well with concentration of VOCs studied. The calculated probability index of cancer risk was 7.9*10/sup -7/ where the measured concentration of benzene in the atmosphere from this studied was employed. |
