title: Atmospheric levels of BTEX compounds during the 2008 Olympic Games in the urban area of Beijing.
abstract: The hourly concentrations of BTEX (Benzene, Toluene, Ethylbenzene, m,p-Xylene and o-Xylene) in the urban area of Beijing were measured during July-October 2008, covering the periods of the 2008 Olympic Games and Paralympic Games. The atmospheric BTEX were pre-concentrated on Tenax-TA tubes, and analyzed by GC-PID (Gas Chromatography with Photo Ionization Detector) after thermal desorption. During the games, the mean daytime concentrations of benzene, toluene, ethylbenzene, m,p-xylene and o-xylene were 2.37, 3.97, 1.92, 3.51 and 1.90 microg/m3, respectively, and were 52.8%, 63.9%, 56.4%, 56.8% and 46.9%, respectively lower than those after the games. The significantly positive correlation between BTEX and CO as well as the ratio of benzene/toluene suggested that the vehicle exhaust was the major source of BTEX during the whole investigated period. The extremely high ratios of ethylbenzene to m,p-xylene (E/X) were mainly observed at noontime in haze days, indicating that photochemical reactions were highly active under these typical days.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Liu
authors.forename: Yujing
authors.initials: Y
authors.lastname: Mu
authors.forename: Yujie
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Wang
authors.forename: Yanju
authors.initials: Y
authors.lastname: Liu
authors.forename: Zhenquan
authors.initials: Z
authors.lastname: Sun
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D001272:Atmosphere / Q000737:chemistry*; D001555:Benzene Derivatives / Q000032:analysis* / Q000737:chemistry; D002248:Carbon Monoxide / Q000032:analysis; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D038622:Internationality; D010777:Photochemistry; D013177:Sports; D013997:Time Factors; D014050:Toluene / Q000032:analysis; D014505:Urban Population; D001335:Vehicle Emissions / Q000032:analysis; D014835:Volatilization; D014992:Xylenes / Q000032:analysis
chemical_list: D000393:Air Pollutants; D001555:Benzene Derivatives; D001335:Vehicle Emissions; D014992:Xylenes; D014050:Toluene; D002248:Carbon Monoxide