Sources of C₂-C₄ alkenes, the most important ozone nonmethane hydrocarbon precursors in the Pearl River Delta region.
Sources of C₂-C₄ alkenes, the most important ozone nonmethane hydrocarbon precursors in the Pearl River Delta region.
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DOI：
10.1016/j.scitotenv.2014.09.024
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Yanli Zhang;Xinming Wang;Zhou Zhang;Sujun Lü;Zhonghui Huang;Longfeng Li
中科院分区：
文献类型：
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作者：
Yanli Zhang;Xinming Wang;Zhou Zhang;Sujun Lü;Zhonghui Huang;Longfeng Li
在中国的特大城市，如位于高度工业化和人口密集的珠江三角洲（PRD）地区的城市中心，地面臭氧正成为一个日益关注的问题，以前的研究表明，臭氧的产生对VOC排放敏感，烯烃是重要的前体。然而，对烯烃的来源知之甚少。本文介绍了2009年11月至12月期间在珠三角地区四个具有代表性的城市、郊区和农村地区进行的环境挥发性有机化合物监测，这些地区经历了频繁的臭氧事件。C2-C4烯烃占非甲烷碳氢化合物（NMHCs）总量的11-20%，占NMHCs臭氧生成潜能（OFPs）的38-64%，占NMHCs总羟基自由基（OH）反应活性的30-50%。乙烯是最丰富的烯烃，占NMHCs总混合比例的8-15%，占OFPs的25-46%。C2-C4烯烃与典型源示踪剂的相关性表明，乙烯可能主要与汽车尾气和工业活动有关，而丙烯和丁烯则与液化石油气有关。正矩阵分解（PMF）证实，汽车尾气和液化石油气（LPG）是乙烯、丙烯、1-丁烯、反式-2-丁烯和顺式-2-丁烯的两个主要来源，分别占52- 62%、58- 77%、73- 83%、68-79%和73-84%。仅汽车尾气就贡献了32-49%的乙烯和35-41%的丙烯。工业活动贡献了13-23%的乙烯和7-20%的丙烯。LPG反而对丁烯（38-65%）和丙烯（23-36%）贡献最大。广泛的测试证实，在广州使用的液化石油气和液化石油气燃烧羽流中，丙烯和丁烯的含量很高;因此，限制液化石油气中的烯烃含量将有利于区域臭氧控制。
Surface ozone is becoming an increasing concern in China's megacities such as the urban centers located in the highly industrialized and densely populated Pearl River Delta (PRD) region, where previous studies suggested that ozone production is sensitive to VOC emissions with alkenes being important precursors. However, little was known about sources of alkenes. Here we present our monitoring of ambient volatile organic compounds at four representative urban, suburban and rural sites in the PRD region during November–December 2009, which experienced frequent ozone episodes. C2–C4alkenes, whose total mixing ratios were 11–20% of non-methane hydrocarbons (NMHCs) quantified, accounted for 38–64% of ozone formation potentials (OFPs) and 30–50% of the total hydroxyl radical (OH) reactivity by NMHCs. Ethylene was the most abundant alkene, accounting for 8–15% in total mixing ratios of NMHCs and contributed 25–46% of OFPs. Correlations between C2–C4alkenes and typical source tracers suggested that ethylene might be largely related to vehicle exhausts and industry activities, while propene and butenes were much more LPG-related. Positive Matrix Factorization (PMF) confirmed that vehicle exhaust and liquefied petroleum gas (LPG) were two major sources that altogether accounted for 52–62%, 58–77%, 73–83%, 68–79% and 73–84% for ethylene, propene, 1-butene, trans-2-butene and cis-2-butene, respectively. Vehicle exhausts alone contributed 32–49% ethylene and 35–41% propene. Industry activities contributed 13–23% ethylene and 7–20% propene. LPG instead contributed the most to butenes (38–65%) and substantially to propene (23–36%). Extensive tests confirmed high fractions of propene and butenes in LPG then used in Guangzhou and in LPG combustion plumes; therefore, limiting alkene contents in LPG would benefit regional ozone control.