北京怀柔O_3污染过程初始VOCs浓度特征及来源分析  

Characteristics and Source Analysis of Initial Mixing Ratio of Atmospheric VOCs during an Ozone Episode in Huairou,Beijing

作　　者：胡君 王淑兰[2] 吴亚君[2] 张敬巧 张萌[2] 王涵[2] 柴发合[2] HU Jun;WANG Shulan;WU Yajun;ZHANG Jingqiao;ZHANG Meng;WANG Han;CHAI Fahe(College of Water Sciences,Beijing Normal University,Beijing 100875,China;Chinese Research Academy of Environmental Sciences,Beijing 100012,China)

机构地区：[1]北京师范大学水科学研究院,北京100875 [2]中国环境科学研究院,北京100012

出　　处：《环境科学研究》2019年第5期766-775,共10页Research of Environmental Sciences

基　　金：国家环境保护公益性行业科研专项(No.201509002)~~

摘　　要：为了解北京怀柔区夏季典型O_3污染过程中初始VOCs (挥发性有机物)浓度(以φ计)的特征,识别其关键物种及主要来源,于2016年8月3—11日在中国科学院大学雁栖湖校区教学楼顶开展强化观测,利用光化学物种比值法和连续反应模型法测算观测期间大气初始φ(VOCs),采用MIR (最大增量反应活性)法估算初始VOCs的OFP (O_3生成潜势),识别关键物种,并应用PMF (正交矩阵因子)模型对初始VOCs的来源进行解析.结果表明:北京怀柔区O_3污染过程中初始φ(VOCs)平均值为25. 27×10-9,如忽略化学损失,φ(VOCs)将被低估约18. 6%.初始VOCs的总OFP值为144. 6×10-9,VOCs物种对总OFP贡献率的顺序依次为醛酮类>烯烃>芳香烃>烷烃,异戊二烯、乙醛、己醛、间/对-二甲苯、甲苯、乙烯、丙烯、1,2,4-三甲苯、丁酮、1,3,5-三甲苯是怀柔区O_3形成的关键活性物种. PMF解析结果显示,机动车尾气源对初始φ(VOCs)的贡献率(23. 5%)最高,其次是溶剂使用源(18. 3%)、植物排放源(18. 1%)、工业过程源(17. 6%)、生物质燃烧源(12. 1%)和煤炭燃烧源(10. 5%).研究显示,在北京怀柔区典型O_3污染过程中,减少机动车尾气源、溶剂使用源、上风向工业过程源的排放是控制怀柔区VOCs的有效措施,而控制异戊二烯、乙醛、己醛、间/对-二甲苯、甲苯等关键活性物种则是有效抑制VOCs排放对O_3生成贡献的重要手段.In order to understand the characteristics of initial VOCs(volatile organic compounds),identify their key compounds and source apportionment during a typical ozone(O3) episode in summer in Huairou,Beijing,a field campaign was conducted on the roof of a building on the Yanqi Lake Campus of the Chinese Academy of Sciences from August 3 rdto 11 th,2016. The initial mixing ratio of VOCs in the episode was calculated using ratio method and sequential reaction model method. The ozone formation potential(OFP) of the initial VOCs was estimated by the MIR method(maximum incremental reactivity) to identify the key species. And possible sources were examined using the EPA PMF model. The results show that the initial mixing ratio of VOCs was 25. 27 × 10^-9 and the ratio would be underestimated by 18. 6% without consideration of VOCs consumed by reactions. The average OFP value was 144. 6 × 10^-9,carbonyls played the most important role in O3 formation,followed by alkenes,aromatics and alkanes. The key VOC species identified were isoprene,n-hexanal,acetaldehyde,m/p-xylene and toluene. Source analysis shows that vehicle emissions made the largest contribution(23. 5%) to the initial VOCs,followed by solvent use(18. 3%),biogenic emissions(18. 1%),industrial processes(17. 6%),biomass burning(12. 1%) and combustion emissions(10. 5%). Thus,controlling emissions of vehicles nearby,solvent use and industries upwind would reduce VOC levels and controlling the key species such as isoprene,n-hexanal,acetaldehyde,m/p-xylene and toluene would reduce O3 levels during typical O3 episodes.

关 键 词：VOCS VOCs初始浓度 O3生成潜势 来源解析 

分 类 号：X515[环境科学与工程—环境工程]