Understanding the Relationship between Oxidative Potential and Individual Particulate Organic Components in a Residential City of South Korea
SUNG-WON PARK, Ji-Won Jeon, Pyung-rae Kim, Hyo-Won Lee, Soo-Jin Jeong, Yun-seo Lee, Young-Ji Han, Kangwon National University
Abstract Number: 641
Working Group: Health-Related Aerosols
Abstract
Particulate matter with a diameter of 2.5 micrometers or less (PM2.5) is a significant concern for air quality of Northeaste Asia due to its adverse health effects. While the mass concentration of PM2.5 is a critical metric, recent research emphasizes the importance of understanding the toxicity of these particles . One key measure of this toxicity is the oxidative potential (OP) of PM2.5, which quantifies the capacity to produce reactive oxygen species (ROS). These ROS can induce oxidative stress and inflammation in biological tissues, leading to various adverse health effects, even at low PM2.5 mass concentrations.
In this study, antioxidants including ascorbic acid (AA) and reduced glutathione (GSH), and dithiothreitol (DTT) were used to assess the OP of PM2.5 collected in Chuncheon, a medium-sized residential city in South Korea. Situated downwind of China and metropolitan areas of Korea, the air quality in this city can be significantly affected by regional- and long-range transport. A previous study found that secondary organic aerosol (SOA) significantly increased during high PM2.5 concentration episodes. This study aims to measure the OP of PM2.5 during four seasons and to identify the effects of various PM2.5 components including ionic, metallic, and 47 individual organic compounds, on OP. During the study period, the average PM2.5 concentration was 24.7 ± 15.8 μg m-3, higher in winter and lower in summer. Among organic components, sugar compounds (tracers for biomass burning) and dicarboxylic acids (markers of SOA) were predominant in the total organic matter measured. Additionally, SOA marker species derived from isoprene were observed to be highest in June. Average mass- normalized OP measured by depletion of AA (OPmAA), GSH (OPmGSH), and DTT (OPmDTT) were 2.3 ± 0.4, 1.6 ± 0.7, and 10.2 ± 3.2 pmol min-1 mg-1, respectively. OPmAA showed significant correlations with saturated fatty acids and sugars, while OPmDTT correlated significantly with biogenic-SOA tracers. These findings necessitate consideration of individual organic components when evaluating OP. Possible sources for the extrinsic OP were also apportioned by Positive Matric Factorization (PMF) in this study, and the results differed considerably from the source apportionment for PM2.5 concentration.