title: [Characteristics of ambient VOCs and their role in O3 formation: a typical air pollution episode in Shanghai urban area].
abstract: The concentration, speciation and chemical reactivity of ambient volatile organic compounds (VOCs) in shanghai city were analyzed and measured by using online gas chromatography with flame ionization detection systems (GC-FID) during a typical air pollution episode (from Oct. 30th to Nov. 2nd, 2010) and 55 kinds of VOCs were detected. The results show that averaged concentrations of VOCs was 27 x 10(-9) before the episode, and then dramatically increased by 3 times (87 x 10(-9)) in the episode than the former, the main components were alkanes (35.2 x 10(-9)), aromatics (30.0 x 10(-9)), alkenes (21.6 x 10(-9)). Furthermore, the maximum ozone formation potential (PhiOFP) is analyzed and showed that PhiOFP (in the episode) > PhiOFP (after the episode) PhiOFP (before the episode). Before the episode, the percent of PhiOFP for aromatics 53.0% , alkenes 36. 1% and alkanes 11.7%; in the episode, the percent of PhiOFP for aromatics 54.7%, alkenes 36.7% and alkanes 9.8%; after the episode, the percent of PhiOFP for alkenes 52.7%, aromatics 36.0% and alkanes 13.2%. Alkenes (C2-C4) and aromatics (C6-C8) are the main components for the ozone formation, namely toluene, m,p-xylene, 1,3-butadiene, propene, ethene et al. In addition, the relationship is negative and nonlinear between the O3 and PhiOFP. And efficiencies of PhiOFP formed into O3 are below 20. 0% in different stage of episode. This is very important and meaningful for the quantitative evaluate the influence of VOCs towards O3.
authors.affiliation: Shanghai Environmental Monitoring Center, Shanghai 200030, China. cuihx@semc.gov.cn
authors.forename: Hu-Xiong
authors.initials: HX
authors.lastname: Cui
authors.forename: Ya-Ming
authors.initials: YM
authors.lastname: Wu
authors.forename: Song
authors.initials: S
authors.lastname: Gao
authors.forename: Yu-Sen
authors.initials: YS
authors.lastname: Duan
authors.forename: Dong-Fang
authors.initials: DF
authors.lastname: Wang
authors.forename: Yi-Hua
authors.initials: YH
authors.lastname: Zhang
authors.forename: Qing-Yan
authors.initials: QY
authors.lastname: Fu
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D002849:Chromatography, Gas / Q000379:methods; D002947:Cities; D004784:Environmental Monitoring; D010126:Ozone / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D055549:Volatile Organic Compounds; D010126:Ozone