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The objective of this study was to compare volatile organic compounds (VOC) concentrations from six main roads in Taiwan's third largest city (Taichung) and determine factors that affect VOC concentrations. Twenty-two VOC compounds were determined on six roads using US E.P.A method TO-17. 0.2 g of Carbopack B was used as an adsorbant collector and thermal desorption and gas chromatography/mass spectrometry (GC/MS) techniques were used to analyze VOCs. Results showed that car and motorcycle commuters were exposed to the highest VOC concentrations on Ta-Ya Road (2149 and 1343 μg m−3., respectively). Except for Ta-Ya Road and Chung-Kang Road, motorcycle commuters were exposed to higher VOC concentrations than their driving counterparts. Four sampling periods were used in the study; exposure to VOC concentrations was highest from 7:30 to 8:30 AM for motorcycle commuters (1515 μg m−3) and from 5:00 to 6:00 AM for car commuters (1071 μg m−3), while concentrations for all commuters were lowest from 2:00 to 3:00 P.M. Concentrations were negatively correlated to percentage of vacant lots along the road (PVL), yet not correlated to traffic volume. The ratios for toluene, benzene, xylene, and ethylbenzene (T : B : X : E) were similar for car commuters (5.5 : 2.1 : 2.6 : 1.0) and motorcycle commuters (5.7 : 2.0 : 2.6 : 1.0) which, combined with other published data, strongly suggest a vehicular source for hydrocarbons in Taichung. Comparing these concentrations, Taichung was slightly lower than Taipei but 2–30 times higher than cities of other countries. It is concluded that the chronic exposure to high concentrations of hydrocarbons may pose a serious health risk to commuters in Taichung |
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