| Summary: | 碩士 === 台北醫學院 === 公共衛生學研究所 === 87 === Motorcycle is a kind of open vehicles. Motorcyclists expose to air pollutants more than those people who choose other traffic patterns. In Taiwan, motorcycles are the most common vehicles. It is important to approach air pollutants exposure of motorcyclists in different riding conditions . This study measured the in-riding concentrations of 10 gasoline-related monocyclic aromatic hydrocarbons(MAHs) by the Solid Sorbent-Thermal Desorption-Gas Chromatography Method .Motorcyclist with personal sampler was riding in one section of main street of Taipei. Samples were transferred to the laboratory and were analyzed within one week. The countryside air was also sampled and analyzed during the study period for comparison.
Sampling was performed at different time period of workdays to measure the variation of MAHs concentrations . Factors such as different traffic patterns, sampling time, wind speed, relative humidity, temperature, and atmospheric pressure, were evaluated. A total of 156 samples was collected from March to May of 1999.
The benzene and toluene concentrations did not change when data were compared of the results obtained from 1991. Compared with foreign studies, the concentrations of benzene and toluene are 14~34 and 15~65 times higher.
However, there was no significant difference between our results and foreign studies in MAHs exposure concentration when the exposure of country riders were investigated. The concentrations of 10 MAHs sampled from countryside were significantly lower than Taipei metropolitan samples. The lowest concentration in rural sample was only 6.6% of the lowest city sample.
The concentration ratios of MAHs between 8:00~9:00, 17:00~18:00, 21:00~23:00, 15:00~17:00 and 18:00~19:00, 23:00~6:00,were 6: 5.9: 4.1: 3.1: 2.3: 1. The time spent for riding the same distance varied during different time periods. By weighting both concentrations and duration of exposure , the ratios of MAHs exposure dose were 10.3：10.5：5.6：4.7：3.3：1.
Only the wind speed showed negative association when the relationship of MAHs concentrations and meteorological factors were considered. Other factors, such as humidity , temperature and atmospheric pressure existed no correlation with pollutants concentrations.
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