Spatial and seasonal trends in biogenic secondary organic aerosol tracers and water-soluble organic carbon in the southeastern United States
Spatial and seasonal trends in biogenic secondary organic aerosol tracers and water-soluble organic carbon in the southeastern United States
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DOI：
10.1021/es7032636
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发表时间：
2008-07-15
影响因子：
11.4
通讯作者：
Wang, Xinming
中科院分区：
文献类型：
--
作者：
Ding, Xiang;Zheng, Mei;Wang, Xinming
2004年5月至2005年4月，在一个农村网站和三个城市网站位于美国东南部的细颗粒物（PM2.5）的24小时综合过滤器样品收集。过滤器提取和分析两个生物源的二次有机气溶胶（SOA）示踪剂，通过气相色谱-质谱（GC-MS），和水溶性有机碳（WSOC）的浓度。在这项研究中报道的示踪剂包括异戊二烯衍生的2-甲基苏糖醇和2-甲基异麦芽糖醇，以及蒎烯衍生的顺式蒎酮酸。2-甲基四醇（2-甲基戊糖醇和2-甲基苏糖醇的总和）、顺式-皮诺酸和WSOC的平均环境浓度分别为21.7至94.3纳克/立方米、5.31至17.9纳克/立方米和1.87至3.18微克/立方米。不同的空间分布观察到的所有示踪剂的浓度最高的农村网站和最低水平的沿海网站。虽然2-methyltetrol的WSOC的小部分，从0.35%在城市网站的最高分数1.09%在农村网站，WSOC表现出显着的相关性与2-methyltetrol在夏季，这表明异戊二烯SOA的WSOC作出了重要贡献。2-甲基四醇在夏季的浓度最高，当高温，强烈的太阳辐射，和高臭氧水平发生。然而，没有发现明显的季节变化的顺式-蒎酮酸。内陆网站之间的WSOC是空间上均匀的2-甲基四醇，这表明WSOC是由多种机制。
Twenty-four hour integrated filter samples of fine particulate matter (PM2.5) were collected from May 2004 to April 2005 at one rural site and three urban sites located in the southeastern United States. Filters were extracted and analyzed for both biogenic secondary organic aerosol (SOA) tracers via gas chromatography-mass spectrometry (GC-MS), and water-soluble organic carbon (WSOC) concentrations. The tracers reported in this study include isoprene-derived 2-methylthreitol and 2-methylerythritol, as well as pinene-derived cis-pinonic acid. The mean ambient concentrations ranged from 21.7 to 94.3 ng/m(3), 5.31 to 17.9 ng/m(3), and 1.87 to 3.18 mu gC/m(3) for 2-methyltetrols (sum of 2-methylerythritol and 2-methylthreitol), cis-pinonic acid and WSOC, respectively. Distinct spatial distributions were observed for all tracers with the highest concentration at the rural site and the lowest level at a coastal site. Although 2-methyltetrols were small fractions of WSOC, varying from 0.35% at an urban site to highest fractions of 1.09% at the rural site, WSOC exhibited significant correlation with 2-methyltetrols during summer, suggesting isoprene SOA makes an important contribution to WSOC. 2-Methyltetrols had the highest concentrations during the summer, when high temperature, intense solar radiation, and high ozone level occurred. However, no obvious seasonal variation was found for cis-pinonic acid. Between inland sites WSOC was more spatially homogeneous than the 2-methyltetrols, suggesting that WSOC was produced from a variety of mechanisms.