Personal Exposure Assessment to Air Pollution for Motorcycle Commuters

• Main Authors: Tzu-Hsuan Wang, 王子瑄
• Other Authors: 莊振義
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/he75sy

碩士 === 國立臺灣大學 === 地理環境資源學研究所 === 106 === Air pollution emitted from vehicles is recognized as one critical environmental issue for commuters in many metropolitans in recently years. However, previous studies focused more on emission sources but seldom considered the influences of the weather patterns and urban microenvironment. Thus, it is important to quantify the personal exposure during commuting and further estimate the effects of environmental factors. The objectives of this study were to measure the exposure of motorcycle commuters in the Taipei metropolitan area to target air pollutants, including PM2.5, PM10, CO, and pPAHS, and further evaluate the influences of the meteorological patterns and the local built environment. This study used a quantitative method to choose sampling periods and route, which is different from previous qualitative studies. The sampling periods were decided by statistically analyzing air pollution data from Taiwan EPA’s air quality monitoring stations, in addition, the ordinary kriging was used to find the most polluted area and determine the appropriate sampling route. Real-time mobile monitoring on street scale was conducted during the evening traffic rush hour (17:30~18:30) from July 2017 to April 2018. The chosen sampling route starts from National Taiwan University from a park in Sangchong, and the total length is around 10 km. The exposure doses for PM10 and PM2.5 in the event day (2.2 μg km-1, 1.8 μg km-1) were 2.0 and 6.0 times higher than the averages of weekday (1.1 μg km-1, 0.3 μg km-1), respectively. In addition, the average exposure doses for pPAHS and CO in weekdays (7.9 ng km-1; 0.5 mg km-1) were 1.2 and 2.5 times higher than weekends (6.7 μg km-1; 0.2 mg km-1), respectively. Correlation matrix results show that under both the cold front and high pressure reflux weather patterns, the concentrations of PM10 and PM2.5 was negatively affected by the driving speed of motorcycle, although the result was not statistically significant. Besides, under the high pressure reflux, the aspect ratio was positively correlated with PM10, whereas, the effect of aspect ratio under the cold front wasn’t shown. The number of motorcycle positively correlated with CO under two weather patterns, but due to the coarse resolution of the data, the result was not statistically significant either. Additionally, the exposure concentrations are strongly affected by the stop-and-go movement. By using one-tailed independent sampling t test, the mean concentration of PM10 and PM2.5 (65.3 μg m-3, 14.2 μg m-3) while waiting for the traffic light was significantly higher (p<0.05) than moving (45.2 μg m-3, 12.5 μg m-3). Comparing the concentrations between sidewalk and on-road, the on-road CO concentration was around 1.1~30.0 times higher than those of sidewalk during each mobile-monitoring, whereas, PM10 and PM2.5 didn’t shown the similar results. These results demonstrate the important contributions of environmental effects to pollutant concentration on street scale, and thus the results can not only provide information for risk analysis in the field of public health, but also serve as an important reference for air quality management.