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J Environ Sci (China)

Title:		"Commuter exposure to BTEX in public transportation modes in Bangkok, Thailand"
Author(s):		Ongwandee M; Chavalparit O;
Address:		"Faculty of Engineering, Mahasarakham University, Kantarawichai District, Mahasarakham 44150, Thailand. maneerat.o@msu.ac.th"
Journal Title:		J Environ Sci (China)
Year:		2010
Volume:		22
Issue:		3
Page Number:		397 - 404
DOI:		10.1016/s1001-0742(09)60121-2
ISSN/ISBN:		1001-0742 (Print) 1001-0742 (Linking)
Abstract:		"Measurements and monitoring of volatile organic compounds (VOCs) have been conducted in the metropolitan Bangkok. However, in-vehicle levels of VOCs are still lacking. This study investigated VOCs concentrations in four public transportation modes in Bangkok, Thailand during two rush hour periods (7:00-9:00 a.m. and 4:00-7:00 p.m.). The four modes included an air-conditioned bus (A/C bus), non-air-conditioned bus (non-A/C bus), electric sky train, and a passenger boat traveling along the canal. Comparison among three important bus routes was also studied. In-vehicle air samples were collected using charcoal sorbent tubes and then analyzed by a gas chromatography-mass spectrometer. Results showed that the transportation modes significantly influenced the abundance of in-vehicle benzene, toluene, ethylbenzene, and m,p-xylene (BTEX). Median concentrations of BTEX were 11.7, 103, 11.7, and 42.8 microg/m3 in A/C bus; 37.1, 174, 14.7, and 55.4 microg/m3 in non-A/C bus; 2.0, 36.9, 0.5, and 0.5 Cig/m3 in sky train; and 3.1, 58.5, 0.5, and 6.2 microg/m3 in boat, respectively. Wilcoxon rank sum test indicated that toluene and m,p-xylene in the sky trains were statistically lower than that in the other three modes at a p-value of 0.05. There were statistical differences in TEX concentrations among the bus routes in the non-A/C buses. In addition, the benzene to toluene ratios implied that tail-pipe emissions were important contributor to the abundance of in-vehicle VOCs"
Keywords:		Air Pollutants/*chemistry Benzene/*chemistry Benzene Derivatives/*chemistry Cities *Environmental Exposure Humans Motor Vehicles Thailand Time Factors Toluene/*chemistry Vehicle Emissions/analysis Volatile Organic Compounds/chemistry Xylenes/*chemistry;
Notes:		"MedlineOngwandee, Maneerat Chavalparit, Orathai eng Research Support, Non-U.S. Gov't Netherlands 2010/07/10 J Environ Sci (China). 2010; 22(3):397-404. doi: 10.1016/s1001-0742(09)60121-2"