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Lee SJ, Ju JT, Lee JJ, Song CK, Shin SA, Jung HJ, Shin HJ, Choi SD. Mapping nationwide concentrations of sulfate and nitrate in ambient PM 2.5 in South Korea using machine learning with ground observation data. Sci Total Environ 2024; 926:171884. [PMID: 38527532 DOI: 10.1016/j.scitotenv.2024.171884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/24/2024] [Accepted: 03/20/2024] [Indexed: 03/27/2024]
Abstract
Particulate matter (PM) is a major air pollutant in Northeast Asia, with frequent high PM episodes. To investigate the nationwide spatial distribution maps of PM2.5 and secondary inorganic aerosols in South Korea, prediction models for mapping SO42- and NO3- concentrations in PM2.5 were developed using machine learning with ground-based observation data. Specifically, the random forest algorithm was used in this study to predict the SO42- and NO3- concentrations at 548 air quality monitoring stations located within the representative radii of eight intensive air quality monitoring stations. The average concentrations of PM2.5, SO42-, and NO3- across the entire nation were 17.2 ± 2.8, 3.0 ± 0.6, and 3.4 ± 1.2 μg/m3, respectively. The spatial distributions of SO42- and NO3- concentrations in 2021 revealed elevated concentrations in both the western and central regions of South Korea. This result suggests that SO42- concentrations were primarily influenced by industrial activities rather than vehicle emissions, whereas NO3- concentrations were more associated with vehicle emissions. During a high PM2.5 event (November 19-21, 2021), the concentration of SO42- was primarily influenced by SOX emissions from China, while the concentration of NO3- was affected by NOX emissions from both China and Korea. The methodology developed in this study can be used to explore the chemical characteristics of PM2.5 with high spatiotemporal resolution. It can also provide valuable insights for the nationwide mitigation of secondary PM2.5 pollution.
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Affiliation(s)
- Sang-Jin Lee
- Department of Civil, Urban, Earth, and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jeong-Tae Ju
- Department of Civil, Urban, Earth, and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jong-Jae Lee
- Research and Management Center for Particulate Matter in the Southeast Region of Korea, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Chang-Keun Song
- Department of Civil, Urban, Earth, and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea; Research and Management Center for Particulate Matter in the Southeast Region of Korea, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea; Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Sun-A Shin
- Climate and Air Quality Research Department, National Institute of Environmental Research, Incheon, 22689, Republic of Korea
| | - Hae-Jin Jung
- Climate and Air Quality Research Department, National Institute of Environmental Research, Incheon, 22689, Republic of Korea
| | - Hye Jung Shin
- Climate and Air Quality Research Department, National Institute of Environmental Research, Incheon, 22689, Republic of Korea
| | - Sung-Deuk Choi
- Department of Civil, Urban, Earth, and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea; Research and Management Center for Particulate Matter in the Southeast Region of Korea, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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