https://scholarworks.unist.ac.kr/handle/201301/20 2026-05-13T08:32:02Z 2026-05-13T08:32:02Z Go, Minji Kim, Nam-Kyu Ju, Jeong-Tae Choi, Sung-Deuk https://scholarworks.unist.ac.kr/handle/201301/91658 2026-05-12T00:30:22Z 2026-06-30T15:00:00Z

Title: Spatial and seasonal distributions of parent, nitrated, and oxygenated PAHs and health risks in a major industrial city in Korea Author(s): Go, Minji; Kim, Nam-Kyu; Ju, Jeong-Tae; Choi, Sung-Deuk Abstract: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous atmospheric pollutants, and their nitrated (NPAHs) and oxygenated (OPAHs) derivatives originate from both primary sources and secondary atmospheric reactions. This study investigated the seasonal and spatial distributions, emission sources, and potential health risks of PAHs, NPAHs, and OPAHs using polyurethane foam-based passive air samplers (PUF-PASs) across 20 sites in Ulsan, South Korea. The concentrations of Sigma 21 PAHs were highest in fall and winter. In contrast, the Sigma 17 NPAH and Sigma 9 OPAH levels showed limited seasonal variation, likely reflecting enhanced photochemical formation in warm seasons and greater primary emissions in cold seasons. Industrial sites exhibited consistently higher levels, reflecting the influence of local emission sources. Correlation analysis and diagnostic ratios indicated that NPAHs and OPAHs were influenced by both primary sources and secondary formation, with a stronger influence of primary emissions on OPAHs in winter. The cancer risk remained below the US EPA threshold (1.0E-06) at all sites. However, relatively higher values were observed in some urban areas. Non-priority PAHs contributed considerably to the total BaPeq, indicating the need for further toxicological evaluation. This study provides a comprehensive understanding of the emission characteristics and secondary formation of PAHs and their derivatives in an industrial city in South Korea.

2026-06-30T15:00:00Z Jeon, Ha Jeong Park, Sang Seo Kim, Jhoon Chai, Yujin Kim, Minseok Yu, Jeong-Ah Kim, Seung-Yeon https://scholarworks.unist.ac.kr/handle/201301/91655 2026-05-11T02:30:25Z 2026-03-31T15:00:00Z

Title: Integration of GEMS and MODIS AOD for enhanced long-term aerosol monitoring over East Asia Author(s): Jeon, Ha Jeong; Park, Sang Seo; Kim, Jhoon; Chai, Yujin; Kim, Minseok; Yu, Jeong-Ah; Kim, Seung-Yeon Abstract: Aerosols significantly affect the Earth’s climate system, yet large uncertainties remain in their long-term records. The Geostationary Environment Monitoring Spectrometer (GEMS) provides high-resolution aerosol data over East Asia, but current aerosol optical depth (AOD) retrievals display systematic biases. To improve data quality, we developed a GEMS–Moderate Resolution Imaging Spectroradiometer (MODIS) referenced AOD (GM-AOD) by processing GEMS Level 3 and applying aerosol type and surface-dependent correction functions derived from MODIS AOD. The algorithm incorporates temporal averaging, AMI-based cloud filtering, land/sea classification, and area-weighted gridding. GEMS initially underestimated MODIS with regression slopes of 0.52–0.54 in 2023–2024. After correction, the slopes improved to 0.82–0.84, with the largest improvement in highly-absorbing fine (HAF) and non-absorbing (NA) aerosols. Case studies of dust and biomass burning events confirmed improved consistency while retaining GEMS’ advantage in detecting localized plumes. Validation with the Aerosol Robotic Network (AERONET) yielded a slope of 0.89, demonstrating that GM-AOD provides a reliable, consistent dataset for long-term aerosol and climate studies in East Asia. © 2026 Informa UK Limited, trading as Taylor & Francis Group.

2026-03-31T15:00:00Z Kim, Taehyung Kim, Eunji Park, Haerin Cha, Dong-Hyun Lee, Johan https://scholarworks.unist.ac.kr/handle/201301/91621 2026-05-06T02:00:40Z 2026-07-31T15:00:00Z

Title: Added value of dynamical downscaling in sub-seasonal tropical cyclone forecast Author(s): Kim, Taehyung; Kim, Eunji; Park, Haerin; Cha, Dong-Hyun; Lee, Johan Abstract: Improving the sub-seasonal forecast of tropical cyclones (TCs) remains a significant challenge for climate models. This study evaluated the characteristics of tropical cyclones (TCs) in sub-seasonal forecasts using the Global Seasonal Forecast System 6 (GloSea6), an operational seasonal-to-sub-seasonal forecasting model operated by the Korea Meteorological Administration (KMA) during June-September (JJAS) from 1993 to 2016 over the western North Pacific (WNP). GloSea6 was found to underestimate TC frequency, tracks, particularly in mid-latitudes, lifetime, and intensity across all months, with the most significant errors occurring in August. To further investigate whether these deficiencies could be mitigated, we conducted a single-case dynamical downscaling experiment for August 2016, a period characterized by particularly low TC forecast skill in GloSea6, based on a single forecast initialization date (25th July 2016) with seven ensemble members. The application of dynamical downscaling demonstrated potential added value by directly improving the simulation of TCs in terms of frequency, structure, intensity, and lifetime, although slight overestimations were observed. Furthermore, improved reproductions of the Indian monsoon and circumglobal teleconnection (CGT), both of which strongly influence the western North Pacific subtropical high (WNPSH), contributed to more accurate forecasts of WNPSH variability and, consequently, better predictions of TC activity in the mid-latitudes and East Asia. Therefore, dynamical downscaling shows promise for enhancing sub-seasonal TC forecasts through both direct improvements in TC characteristics and indirect improvements in the large-scale environment that influences TC activity (e.g., the WNPSH, Indian monsoon, and CGT), although its generality requires assessment across multiple cases and initialization dates.

2026-07-31T15:00:00Z Choi, Seunghye Chun, Mingi Kim, Bomi Yun, Wonsang Bae, Hyokwan Choi, Daehee https://scholarworks.unist.ac.kr/handle/201301/91607 2026-04-30T05:30:03Z 2026-04-30T15:00:00Z

Title: Impact of biodiversity-regulating factors on inhibition of nitrite-oxidizing bacteria in mainstream partial nitritation/anammox: Microbial dynamic and balance Author(s): Choi, Seunghye; Chun, Mingi; Kim, Bomi; Yun, Wonsang; Bae, Hyokwan; Choi, Daehee Abstract: The stability of mainstream partial nitritation/anammox (PN/A) systems is strongly influenced by microbial competition and cooperation. However, conventional operational strategies, such as dissolved oxygen and ammonium limitation, are effective in simplified systems but often fail to account for the complex microbial interactions that are critical for maintaining system stability under mainstream conditions. In this study, biodiversity-regulating strategies were investigated as operational approaches to stabilize mainstream PN/A systems by controlling microbial interactions. Biodiversity regulation was implemented through the combined modulation of electron donor and acceptor availability, as well as stepwise anammox bioaugmentation. A dualcontrol strategy based on ammonium (NH4+-N) and oxygen (O2) limitation was first applied to suppress nitriteoxidizing bacteria (NOB) while maintaining ammonia-oxidizing bacteria (AOB) activity. Subsequently, anammox bioaugmentation was introduced at 5%, 15%, and 30% ratios to further regulate the microbial community structure and evaluate its effect on nitrogen removal performance. Moderate bioaugmentation (15%) maintained balanced interactions among functional microbial groups and supported stable nitrogen removal. By contrast, excessive bioaugmentation (30%) disrupted microbial balance, resulting in reduced AOB activity and increased heterotrophic denitrification. Microbial community analysis revealed that bioaugmentation of Candidatus Brocadia increased microbial diversity, whereas Nitrospira sp. clone b2 became dominant under unstable conditions. These results indicate that the stability of mainstream PN/A systems depends primarily on the regulation of biodiversity-driven microbial interactions, rather than solely on operational parameters.

2026-04-30T15:00:00Z