Pollution Characteristics of Hazardous Air Pollutants in Seoul: Temporal Variation, Source Identification, and Risk Assessment

Abstract

Hazardous air pollutants (HAPs) are primarily emitted from human activities in industrial and urban areas, and they have adverse impacts on human health. While many studies have focused on monitoring individual HAPs in Seoul, simultaneous measurements of various types of HAPs have been rare. In this study, therefore, volatile organic compounds (VOCs), carbonyl compounds, particle-bound polycyclic aromatic hydrocarbons (pPAHs), black carbon (BC), heavy metals, and criteria air pollutants (CAPs) were simultaneously measured at a site in Yangcheon-gu, Seoul, Korea. The concentrations of most VOCs were high in the fall and spring mainly due to low wind speeds. Conversely, several VOCs emitted from solvents in industrial and urban areas exhibited high concentrations in the summer. Benzene was positively correlated with BC and CO, and BC showed a positive correlation with CO and PM2.5. Additionally, pPAHs exhibited a positive correlation with BC and CO, suggesting an association with incomplete combustion. NO2 was negatively correlated with O3, formed by photochemical reactions in the atmosphere. The hourly concentration trends of NOx and SO2 coincided, potentially linked to emissions from non-industrial sources. Higher concentrations of benzene, BC, PM10 pPAHs, NO2, CO, and SO2 were observed during commute times. PM10 concentrations in the fall exceeded the daily national guideline of 100 μg/m3 due to long-range atmospheric transport from China. Despite their relatively low concentrations, acetaldehyde & ethylene oxide, acrylonitrile, and 1,3-butadiene posed significant cancer and non-cancer risks. The findings of this study highlight that the levels and patterns of HAPs in Seoul are mainly influenced by local sources (e.g., solvents, vehicular exhaust, and combustion) as well as longrange atmospheric transport, and their order of priority varies based on levels and associated risks. © (2023), (Korean Society for Atmospheric Environment). All Rights Reserved.