Investigation of organic aerosol sources using fractionated water-soluble organic carbon measured at an urban site

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• 作者：Seung Shik Park^a ; ^{park8162@chonnam.ac.kr} ; Sung Yong Cho^a ; Kyung-Won Kim^b ; Kwon-Ho Lee^c ; Kweon Jung^d
• 关键词：Carbonaceous aerosols ; Secondary organic carbon ; Hydrophilic and hydrophobic water-soluble organic carbons ; EC-tracer method
• 刊名：Atmospheric Environment
• 出版年：2012
• 期刊代码：11_13522310
• 类别：env
• 出版时间：August, 2012
• 卷：55
• 期：Complete
• 页码：64-72
• 文件大小：634 K

摘要

Concentrations of carbonaceous aerosols in PM_2.5, including elemental carbon (EC), organic carbon (OC), bulk water-soluble organic carbon (WSOC), fractionated WSOCs, and water-soluble inorganic species were measured between December 27, 2010 and January 20, 2011, at an urban site of Seoul, Korea. PM_2.5 samples were collected twice a day, e.g., for the daytime (10:00-16:00) and nighttime (16:00-10:00), respectively. A macro-porous XAD7HP resin was used to separately group the liquid extracts into hydrophilic and hydrophobic WSOC (WSOC_HPI and WSOC_HPO). To better understand the contributions of primary and secondary OC (SOC) to WSOC, estimates of SOC were derived using the EC-tracer method and compared with the WSOC fractions. Good correlations among the WSOC, , and oxalate suggest that some of the observed WSOC originated from similar formation processes as those of and oxalate, i.e., formed by an in-cloud or aerosol droplet process. Primary OC was more highly correlated with the WSOC_HPO (m>Rm>²聽=聽0.56) than the WSOC_HPI (m>Rm>²聽=聽0.33), while a better correlation between predicted SOC and WSOC_HPI (m>Rm>²聽=聽0.63) was found than between the predicted SOC and WSOC_HPO (m>Rm>²聽=聽0.47). These results suggest that WSOC_HPI at the site during the winter could be formed by a similar production pathway such as the secondary organic carbon, while primary combustion emissions were a dominant source for the WSOC_HPO during the study period. Sources of WSOC, WSOC_HPI and WSOC_HPO inferred based on the correlations were also clearly demonstrated by source categories identified by principle component analysis. Measurement results suggest that group separation of bulk WSOC extracts could provide important clues for better understanding the sources of OC (or WSOC).