title: The pollution levels of BTEX and carbonyls under haze and non-haze days in Beijing, China.
abstract: The North China Plain including Beijing is frequently suffering from serious haze days in recent years. To best recognize the influence of haze days on regional air quality, the pollution levels of deleterious gases of BTEX (benzene, toluene, ethylbenzene, m,p-xylene and o-xylene) and carbonyls (formaldehyde, acetaldehyde and acetone) under haze and non-haze days were contrastively investigated during the period of September 2008-August 2010 in Beijing. In comparison with non-haze days, remarkable enhancement of BTEX and the carbonyls under haze days in winter was found, with enhancement factors of 1.9-5.7 for BTEX and of 1.5-4.2 for the carbonyls. Whereas the enhancement factors for both BTEX (1.0-3.0) and the carbonyls (1.2-1.9) under haze days in summer were relatively small. The ratios of each BTEX to CO under both haze days and non-haze days exhibited a minimal value in the afternoon, whereas maximal values for the ratios of the carbonyls to CO were usually found in the afternoon. The ratios of each BTEX to CO were extremely greater under haze days than those under non-haze days in winter, but no evident difference was found in summer. The ratios of each carbonyl under both haze days and non-haze days in summer were at least a factor of 2 greater than those in winter and only enhancement of the ratios under haze days was found in winter. The remarkably higher ratios of ethylbenzene to m,p-xylene under haze days than non-haze days in both winter and summer revealed high reactivity of photochemical reactions initiated by OH radicals under haze days.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: Zhangyujie83@126.com.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: yjmu@rcees.ac.cn.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Mu
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Meng
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Xuezhong
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Weiqi
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Centre National de Recherche Scientifique-Institut de Combustion, Aérothermique, Réactivité et Environnement (CNRS-ICARE), 45071 Orléans cedex 02, France.
authors.forename: Abdelwahid
authors.initials: A
authors.lastname: Mellouki
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Xinmin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Shulan
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Fahe
authors.initials: F
authors.lastname: Chai
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere / Q000737:chemistry; D001554:Benzene / Q000032:analysis*; D001555:Benzene Derivatives / Q000032:analysis; D004784:Environmental Monitoring; D014050:Toluene / Q000032:analysis*; D014992:Xylenes / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D001555:Benzene Derivatives; D014992:Xylenes; D014050:Toluene; D001554:Benzene; C004912:ethylbenzene
keywords: BTEX; Carbonyls; Haze; Local emission; Photochemical reaction