https://scholarworks.unist.ac.kr/handle/201301/19 2026-05-13T08:11:46Z https://scholarworks.unist.ac.kr/handle/201301/91690 Title: Monitoring of PCBs and PCNs using passive air samplers in the metropolitan city of Seoul, South Korea: Spatial distribution, seasonal variation, source identification Author(s): 고민지; 이호영; 김성준; Choi, Sung-Deuk Abstract: Polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) are persistent organic pollutants (POPs) and semi-volatile organic compounds characterized by toxicity, bioaccumulation, and environmental persistence. PCBs and PCNs are unintentionally produced during combustion processes or released from legacy commercial products, and they can accumulate in environmental media with the potential for re-emission into the atmosphere, leading to their continuous presence in urban air. In this study, seasonal monitoring of atmospheric PCBs and PCNs was conducted across Seoul, a major metropolitan city in East Asia, using polyurethane foam passive air samplers (PUF-PASs). Samples were Soxhlet-extracted, cleaned up using multi-layer silica gel columns, and analyzed by gas chromatography coupled with a high-resolution mass spectrometer (GC/HRMS). Mean Σ30 PCB concentrations were significantly higher in summer than in winter, suggesting temperature-driven volatilization and strong influences from legacy sources. Mean Σ15 PCN concentrations were also elevated during summer, with higher levels observed in the southwestern part of Seoul, indicating additional contributions from industrial activities. In winter, long-range atmospheric transport under prevailing wind conditions may further influence PCB and PCN concentrations. Principal component analysis indicated that atmospheric PCBs were primarily associated with historical technical mixtures, whereas PCNs reflected mixed contributions from legacy use and combustion-related sources in both seasons. Overall, this study provides high-resolution spatial and seasonal information on atmospheric PCBs and PCNs in a densely populated urban environment. 2025-02-04T15:00:00Z https://scholarworks.unist.ac.kr/handle/201301/91688 Title: Monitoring of PCBs and PCNs using passive air samplers in the metropolitan city of Seoul, South Korea: Spatial distribution, seasonal variation, source identification Author(s): 고민지; 이호영; 김성준; Choi, Sung-Deuk Abstract: Polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) are persistent organic pollutants (POPs) and semi-volatile organic compounds characterized by toxicity, bioaccumulation, and environmental persistence. PCBs and PCNs are unintentionally produced during combustion processes or released from legacy commercial products, and they can accumulate in environmental media with the potential for re-emission into the atmosphere, leading to their continuous presence in urban air. In this study, seasonal monitoring of atmospheric PCBs and PCNs was conducted across Seoul, a major metropolitan city in East Asia, using polyurethane foam passive air samplers (PUF-PASs). Samples were Soxhlet-extracted, cleaned up using multi-layer silica gel columns, and analyzed by gas chromatography coupled with a high-resolution mass spectrometer (GC/HRMS). Mean Σ30 PCB concentrations were significantly higher in summer than in winter, suggesting temperature-driven volatilization and strong influences from legacy sources. Mean Σ15 PCN concentrations were also elevated during summer, with higher levels observed in the southwestern part of Seoul, indicating additional contributions from industrial activities. In winter, long-range atmospheric transport under prevailing wind conditions may further influence PCB and PCN concentrations. Principal component analysis indicated that atmospheric PCBs were primarily associated with historical technical mixtures, whereas PCNs reflected mixed contributions from legacy use and combustion-related sources in both seasons. Overall, this study provides high-resolution spatial and seasonal information on atmospheric PCBs and PCNs in a densely populated urban environment. 2026-02-04T15:00:00Z https://scholarworks.unist.ac.kr/handle/201301/91689 Title: 서울 대기 중 PCBs와 PCNs의 공간적·계절적 오염 특성 Author(s): 고민지; 이호영; 김성준; 이상진; Choi, Sung-Deuk Abstract: Polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) are persistent organic pollutants (POPs) characterized by bioaccumulation and environmental persistence. PCBs and PCNs are unintentionally produced during combustion processes or released from legacy products, leading to their continuous presence in urban air. In this study, seasonal monitoring of atmospheric PCBs and PCNs was conducted across Seoul, a major metropolitan city in East Asia, using polyurethane foam passive air samplers (PUF-PASs). Samples were Soxhlet-extracted, cleaned up using multi-layer silica gel columns, and analyzed by gas chromatography coupled with a high-resolution mass spectrometer (GC/HRMS). Mean Σ30 PCB concentrations were significantly higher in summer than in winter, suggesting temperature-driven volatilization and strong influences from legacy sources. Mean Σ15 PCN concentrations were also elevated during summer, with higher levels observed in the southwestern part of Seoul, indicating additional contributions from industrial activities. In winter, long-range atmospheric transport under prevailing wind conditions may further influence PCB and PCN concentrations. Principal component analysis indicated that atmospheric PCBs were primarily associated with technical mixtures, whereas PCNs reflected mixed contributions from legacy use and combustion-related sources in both seasons. Overall, this study provides high-resolution spatial and seasonal information on atmospheric PCBs and PCNs in a densely populated urban environment. 2025-05-06T15:00:00Z https://scholarworks.unist.ac.kr/handle/201301/91687 Title: Assessment of cumulative inhalation risks of PAHs and metals in an industrial city using machine learning–based concentration reconstruction Author(s): 주정태; 이상진; 고민지; 조인규; Choi, Sung-Deuk Abstract: The evaluation of long-term cumulative exposure to hazardous air pollutants (HAPs) in industrial cities is constrained by the insufficient spatiotemporal coverage of routine monitoring networks. To address this limitation, a Random Forest model was developed to reconstruct historical concentrations of 13 polycyclic aromatic hydrocarbons (PAHs) and eight metals in Ulsan, South Korea. The model was trained using national HAPs monitoring data for PAHs and metals during 2013–2023, together with criteria air pollutants (CAPs) and meteorological variables, and subsequently applied to generate reconstructed concentrations for 2001–2023. Concentration distributions were reconstructed across the air quality monitoring network, providing denser spatial coverage than HAP monitoring stations. The reliability of the model was evaluated using routine national monitoring data employed for model training and further assessed using independent passive and active air sampling conducted in 2024, confirming that temporal trends and spatial contrasts were accurately captured. Major pollution sources were identified through Positive Matrix Factorization (PMF), indicating traffic emissions and the influence of petrochemical, non-ferrous metal, and heavy manufacturing industrial complexes, with distinct spatial hotspots. Cumulative exposure estimates derived from the reconstructed time series were compared with those calculated using a conventional fixed-year approach. Cumulative PAH exposure in urban residential areas was found to be underestimated by the conventional method, as historically elevated PAH concentrations were not accounted for. Conversely, cumulative metal exposure near industrial complexes was overestimated because recent short-term concentration variability was applied across the entire exposure duration. In addition, residential scenario analyses demonstrated that residential relocation can be incorporated into cumulative exposure assessment. These findings indicate that cumulative risk assessment is more reliably supported by machine learning–based reconstruction than by static concentration assumptions, offering practical insights for long-term public health management in cities with limited data. 2026-02-04T15:00:00Z