An analysis of chemical and meteorological characteristics of haze events in the Seoul metropolitan area during January 12–18, 2013

Koo, Youn-Seo; Yun, Hui-Young; Choi, Dae-Ryun; Han, Jin-Seok; Lee, Jae-Bum; Lim, Yongjae

doi:10.1016/j.atmosenv.2018.01.037

Cited by 26 publications

(5 citation statements)

References 57 publications

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“…Many studies have shown that natural and anthropogenic aerosols generated in China could be easily transported by westerlies to receptor areas. These results were derived from analysis of horizontal distributions of aerosol concentrations simulated by the chemical transport model as well as satellite-observed Aerosol Optical Depth (AOD) data 7–12 . Moreover, major factors affecting severe haze events in Korea have been analysed via source appointment studies 13–17 and inverse modelling 18 .…”

Section: Introductionmentioning

confidence: 99%

Impacts of atmospheric vertical structures on transboundary aerosol transport from China to South Korea

Lee

Kim

et al. 2019

Sci Rep

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To forecast haze pollution episodes caused by high concentrations of long-range transported pollutants emitted in the areas upstream of South Korea, it is crucial to study and identify their behaviour. We analysed the three-dimensional air quality structure in Seoul using ground observation data and aerosol lidar measurements to identify vertical aerosol intrusion into the Korean Peninsula during the spring of 2016. The intrusions were particularly affected by the development of the atmospheric boundary layer (ABL) in the leeward regions. The nocturnal pollutant intrusion into the Korean peninsula via the Yellow Sea was examined using measured data. The pollutants first reached the area above the nocturnal boundary layer (548 ± 180 m) and approached ground level on the following day due to convective mixing depending on the convective ABL growth (1182 ± 540 m) in daytime. These intrusion mechanisms were mostly attributed to extremely high concentrations (i.e. >100 μg m−3) of fine particulate matter in the leeward regions, accounting for four of the total of six cases for which the warnings and alerts were issued in Seoul Metropolitan Area over a year-long period (2016). The horizontal and vertical pathways of the long-range transported pollutants and the atmospheric vertical structure were identified as key factors affecting the surface air quality concentration in the leeward regions.

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Section: Introductionmentioning

confidence: 99%

Impacts of atmospheric vertical structures on transboundary aerosol transport from China to South Korea

Lee

Kim

et al. 2019

Sci Rep

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“…In contrast, nitrogen oxide (NO x ) emissions have steadily increased until recently due to the increase of mobile sources, making nitrate the predominant SIA species in Korea. 1,[3][4][5] During the winter to early spring period in Seoul, when the ambient temperatures are cool and westerly winds prevail, nitrate levels signicantly rise, resulting in severe PM 2.5 pollution. 1,6 At cool temperatures, the equilibrium reaction of "NO 2 + NO 3 / N 2 O 5 " is shied toward N 2 O 5 (dinitrogen pentoxide), leading to the formation of nitrate via hydrolysis during the night.…”

Section: Introductionmentioning

confidence: 99%

The formation and transport of HNO₃ over the Yellow Sea and its impact on the January 2018 PM_2.5 episode in Seoul

Park,

Ahn,

Hong

et al. 2024

Environ. Sci.: Atmos.

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“…9 However, traditional studies have mainly focused on high concentration periods, such as the winter and fall seasons, while overlooking insights from low concentration periods, such as the summer season. 10,11 The summer season in Korea is particularly conducive for studying the local emissions and meteorology's impacts on air quality and pollutant formation, as the Asian monsoon typically restricts eastward transport of emissions from eastern China to the Korean peninsula. 8 The traditional approaches to investigating PM characteristics and formation in the real-world typically involve analyzing field measurements or using chemical transport models.…”

Section: Introductionmentioning

confidence: 99%

“…A comprehensive understanding of locally formed PM will provide detailed information on the effects of atmospheric factors such as meteorological and oxidation conditions . However, traditional studies have mainly focused on high concentration periods, such as the winter and fall seasons, while overlooking insights from low concentration periods, such as the summer season. , The summer season in Korea is particularly conducive for studying the local emissions and meteorology’s impacts on air quality and pollutant formation, as the Asian monsoon typically restricts eastward transport of emissions from eastern China to the Korean peninsula …”

Section: Introductionmentioning

confidence: 99%

Understanding the Driving Forces of Summer PM₁ Composition in Seoul, Korea, with Explainable Machine Learning

Hu,

Moon,

Kim

2024

ACS EST Air

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This study leverages explainable machine learning, specifically XGBoost models with Shapley Additive Explanations (SHAP), to explore the chemical properties of atmospheric aerosols in Seoul, Korea, during the summer of 2019. Focusing on non-refractory particulate matter (NR-PM1) properties measured by high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS), the research extends to organic aerosol (OA) sources identified via positive matrix factorization of high-resolution MS data. The models achieved good predictive accuracy (R 2 > 0.90) for all species concentrations, except for hydrocarbon-like OA (HOA) due to frequent concentration fluctuations. The model outcomes aligned well with those previously achieved using conventional methods (chemical transport model and correlational analysis), confirming that relative humidity is associated with nocturnal nitrate concentration and photochemistry associated with sulfate concentration in the summertime in Seoul. Importantly, the models revealed mostly nonlinear relationships between atmospheric factors, such as temperature and particulate matter (PM) components, thereby deepening the understanding of formation processes. Notably, different potential formation mechanisms were discerned for more oxidized oxygenated OA (MO-OOA) and oxidized primary OA (OPOA). For MO-OOA, SHAP analysis showed a plateau in SHAP values at an O x concentration of 0.085 ppm, which suggested potential fragmentation from further oxidation and agreed with previous chamber experiments. Conversely, the lack of a plateau in the O x values for OPOA implied potential ongoing oxidation, suggesting a higher and longer atmospheric oxidation potential. This approach offers rapid and potential insights into complex atmospheric aerosol formation processes. It is essential to acknowledge that SHAP values do not establish causality, and knowledge of the underlying physical and chemical processes was required to conclude valid and comprehensive interpretations of the ML results.

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An analysis of chemical and meteorological characteristics of haze events in the Seoul metropolitan area during January 12–18, 2013

Cited by 26 publications

References 57 publications

Impacts of atmospheric vertical structures on transboundary aerosol transport from China to South Korea

Impacts of atmospheric vertical structures on transboundary aerosol transport from China to South Korea

The formation and transport of HNO₃ over the Yellow Sea and its impact on the January 2018 PM_2.5 episode in Seoul

Understanding the Driving Forces of Summer PM₁ Composition in Seoul, Korea, with Explainable Machine Learning

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An analysis of chemical and meteorological characteristics of haze events in the Seoul metropolitan area during January 12–18, 2013

Cited by 26 publications

References 57 publications

Impacts of atmospheric vertical structures on transboundary aerosol transport from China to South Korea

Impacts of atmospheric vertical structures on transboundary aerosol transport from China to South Korea

The formation and transport of HNO3 over the Yellow Sea and its impact on the January 2018 PM2.5 episode in Seoul

Understanding the Driving Forces of Summer PM1 Composition in Seoul, Korea, with Explainable Machine Learning

Contact Info

Product

Resources

About

The formation and transport of HNO₃ over the Yellow Sea and its impact on the January 2018 PM_2.5 episode in Seoul

Understanding the Driving Forces of Summer PM₁ Composition in Seoul, Korea, with Explainable Machine Learning