Characteristics of roadside volatile organic compounds in an urban area dominated by gasoline vehicles, a case study in Hanoi

• Published in: Chemosphere (Oxford) Vol. 254; p. 126749
• Main Authors: Ly, Bich-Thuy, Kajii, Yoshizumi, Nguyen, Thi-Yen-Lien, Shoji, Koki, Van, Dieu-Anh, Do, Thi-Nhu-Ngoc, Nghiem, Trung-Dung, Sakamoto, Yosuke
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2020
• Subjects: air pollution; Air quality; benzene; BTEX (benzene, toluene, ethylbenzene, xylene); carcinogenicity; case studies; Emission factor; emissions factor; ethylbenzene; gas chromatography; gasoline; GC-FID; health effects assessments; Health risk; meteorological parameters; ozone; Ozone formation potential; particulates; pentane; roads; roadsides; toluene; urban areas; Volatile organic compounds; xylene; Volatile organic compounds; Ozone formation potential; Air quality; Emission factor; GC-FID; Health risk
• ISSN: 0045-6535; 1879-1298; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.126749

Volatile organic compounds (VOCs) are important air pollution issues because of their potential health effects, and the contribution to ground ozone and secondary particulate matter. In this study, 53 VOC species near nine roads in Hanoi were monitored by sampling and analyzed by GC-FID four times per day on weekdays and in the morning on the weekend, from December 2014 to January 2015. In parallel with VOC sampling, vehicle number was counted, and meteorological conditions were recorded. A large share of motorbikes was found, accounted for 82% of overall for all period, and 88% in rush hours. The average TVOC concentration was 305.1 ppb; while those of BTEX were 12.8/27.4/4.8/15.9/6.0 ppb for benzene/toluene/ethylbenzene/m,p-xylenes/o-xylene, respectively. Isopentane was the most abundant species of VOCs. A significant carcinogenic risk of benzene species was found. Ozone formation potential (OFP) of VOCs was of 1752.7 ppb. Levels of VOC species reflected well the transportation volume. Strong correlations between motorbike number related parameters and ethylbenzene were found. High correlations were also found among ethylbenzene and almost all other VOC species. It implied that the majority of VOCs near road emitted from the same source, which is motorbikes. The calculation using emission factors from COPERT 5 model with conditions of fleets in Hanoi showed that VOCs from motorbikes contributed to more than 90% of the VOC level. [Display omitted] •High level of volatile organic compounds, reflecting well transportation volume.•Isopentane was most abundant, implying high fuel evaporation/low engine efficiency.•Motorbikes contribute for more than nine tenth of VOC level.•Ozone potential formation of thousand ppb.•Significant carcinogenic risk.