Characterization of organic aerosols and their precursors in southern China during a severe haze episode in January 2017
Characterization of organic aerosols and their precursors in southern China during a severe haze episode in January 2017
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2017年1月严重雾霾期间中国南方有机气溶胶及其前体的特征
DOI：
10.1016/j.scitotenv.2019.07.123
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发表时间：
2019-11-15
影响因子：
9.8
通讯作者：
Wang, Tao
中科院分区：
文献类型：
--
作者：
Chang, Di;Wang, Zhe;Wang, Tao
中国南方珠江三角洲地区的快速工业化和经济发展导致了人为排放的大幅增加，因此在过去二十年中经常出现雾霾污染。2017年1月初，珠三角地区录得一次严重的区域性雾霾污染事件，PM2.5浓度峰值约为400 μ g m（-3），是该地点有史以来的最高值。在烟霾期间，观察到含氧挥发性有机化合物（OVOCs，33 +/- 16 ppbv）和有机物（41 +/- 15 μ g m-3）的浓度升高，表明二次有机气溶胶（SOA）在烟霾污染形成中的作用增强。水溶性有机碳（WSOC，12.8 +/- 5.5 μ g Cm（-3））在有机气溶胶中占主导地位，WSOC/OC比值为0.63 +/- 0.12，与估算的次生有机碳（SOC）高度相关（R = 0.85），表明在灰霾期间，所测有机气溶胶的次生来源占主导地位。气溶胶中有四种羧酸（草酸、乙酸、甲酸和草酸）（1.30 +/- 0.38 μ g m（-3）），占WSOC碳质量的3.6 +/- 1.2%，草酸是最丰富的种类。同时测量的挥发性有机化合物（VOCs），OVOCs和有机酸气溶胶在这个网站提供了一个机会，调查前体和产品之间的关系，以及潜在的形成途径。水溶性醛和酮主要通过氧化人为VOCs（主要是丙烷、甲苯、正丁烷和间、对二甲苯）产生，是有机酸的主要贡献者。OVOCs的形成主要是由于气相光化学氧化，而WSOC和二羧酸产生的光化学和夜间多相反应。这些研究结果提供了进一步的见解有机化合物的氧化和演变过程中的雾霾污染事件。(c)2019爱思唯尔B. V.保留所有权利。
The rapid industrialization and economic development in the Pearl River Delta (PRD) region of southern China have led to a substantial increase in anthropogenic emissions and hence frequent haze pollution over the past two decades. In early January 2017, a severe regional haze pollution episode was captured in the PRD region, with a peak PM2.5 concentration of around 400 mu g m(-3), the highest value ever reported at this site. During the haze episode, elevated concentrations of oxygenated volatile organic compounds (OVOCs, 33 +/- 16 ppbv) and organic matter (41 +/- 15 mu g m-3) were observed, indicating the enhanced roles of secondary organic aerosols (SOAs) in the formation of haze pollution. Water-soluble organic carbon(WSOC, 12.8 +/- 5.5 mu g C m(-3)) dominated the organic aerosols, with a WSOC/OC ratio of 0.63 +/- 0.12 and high correlation (R = 0.85) with estimated secondary organic carbon (SOC), suggesting the predominance of a secondary origin of themeasured organic aerosols during the haze episode. Four carboxylic acids (oxalic, acetic, formic, and pyruvic acids) were characterized in the aerosols (1.30 +/- 0.38 mu g m(-3)) and accounted for 3.6 +/- 1.2% of WSOC in carbon mass, with oxalic acid as the most abundant species. The simultaneous measurements of volatile organic compounds (VOCs), OVOCs, and organic acids in aerosols at this site provided an opportunity to investigate the relationship between the precursors and the products, as well as the potential formation pathways. Water-soluble aldehydes and ketones, predominantly produced via the oxidation of anthropogenic VOCs (mainly propane, toluene, n-butane, andm, p-xylene), were the main contributors of the organic acids. The formation of OVOCs is largely attributed to gas-phase photochemical oxidation, whereas the WSOC and dicarboxylic acids were produced from both photochemistry and nocturnal heterogeneous reactions. These findings provided further insights into the oxidation and evolution of organic compounds during the haze pollution episode. (c) 2019 Elsevier B.V. All rights reserved.