Park Seung Shik, Kim Ja-Hyun, Jeong Jae-Uk
Department of Environmental Engineering, Chonnam National University, 77 Yongbong-Ro, Buk-ku, Gwangju 500-757, Republic of Korea.
J Environ Monit. 2012 Jan;14(1):224-32. doi: 10.1039/c1em10617a. Epub 2011 Nov 14.
In this study, the characteristics of total water-soluble organic carbon (WSOC) and isolated WSOC fractions were examined to gain a better understanding of the pathway of organic aerosol production. 24 h PM(2.5) samples were collected during the summer (July 28-August 28, 2009) at an urban site in Korea. A glass column filled with XAD7HP resin was used to separate the filtered extracts into hydrophilic (WSOC(HPI)) and hydrophobic (WSOC(HPO)) fractions. The origins of air mass pathways arriving at the sampling site were mostly classified into three types, those originating over the East Sea of Korea that passed over the eastern inland urban and industrial regions (type I); those from the marine (western/southwestern/southern marine) and passed over the national industrial complex regions (type II); and those from northeastern China that passed through North Korea and metropolitan areas of South Korea (type III). Measurements showed an increase in the average WSOC fraction of total OC from the type II to III air mass (53 to 64%) periods. Also, higher SO(4)(2-)/SO(x) (=SO(2) + SO(4)(2-)) was observed in the type III air mass (0.70) than those in the types I (0.49) and II (0.43). According to the average values of WSOC/OC and SO(4)(2-)/SO(x), measurements suggest that the aerosols collected during the type III air mass period were more aged or photo-chemically processed than those during the types I and II air mass periods. The relationship between the SO(4)(2-)/SO(x) and WSOC/OC (R(2) = 0.64) suggests that a significant fraction of the observed WSOC at the site could be formed by an oxidation process similar to SO(4)(2-) aerosols, probably the oxidation process using OH radicals, or in-cloud processing. The photochemical production of WSOC(HPO) was also observed to significantly contribute to the total OC.
在本研究中，对总水溶性有机碳（WSOC）及其分离组分的特性进行了研究，以便更好地了解有机气溶胶的生成途径。于2009年夏季（7月28日至8月28日）在韩国一个城市站点采集了24小时的PM(2.5)样本。使用填充有XAD7HP树脂的玻璃柱将过滤后的提取物分离成亲水（WSOC(HPI)）和疏水（WSOC(HPO)）组分。到达采样点的气团路径来源主要分为三种类型：起源于朝鲜东海并经过东部内陆城市和工业区的气团（I型）；来自海洋（西部/西南部/南部海洋）并经过国家工业园区的气团（II型）；以及来自中国东北并经过朝鲜和韩国大都市地区的气团（III型）。测量结果表明，从II型到III型气团期间，总有机碳中WSOC的平均占比有所增加（从53%增至64%）。此外，III型气团中的SO(4)(2-)/SO(x)（=SO(2)+SO(4)(2-)）值（0.70）高于I型（0.49）和II型（0.43）。根据WSOC/OC和SO(4)(2-)/SO(x)的平均值，测量结果表明，III型气团期间采集的气溶胶比I型和II型气团期间的气溶胶老化程度更高或光化学处理程度更高。SO(4)(2-)/SO(x)与WSOC/OC之间的关系（R(2)=0.64）表明，该站点观测到的WSOC的很大一部分可能是通过类似于SO(4)(2-)气溶胶的氧化过程形成的，可能是利用OH自由基的氧化过程或云内处理过程。还观察到WSOC(HPO)的光化学生成对总有机碳有显著贡献。
