Ozone production characteristics during the Korea-United States Air Quality campaign over the Seoul Metropolitan Area deciphered by observationally constrained hydroxyl radical reactivity

Bibliographic Data

ID22105330
AuthorsSaewung Kim (0000-0003-4847-3272, University of California, Irvine), Daun Jeong (0000-0002-7059-1008, University of California, Irvine), Yingnan Zhang (0000-0002-9368-8814, 1Department of Earth System Science, School of Physical Sciences, University of California, Irvine, Irvine, CA, USA), Jinsoo Choi (0000-0003-2133-108X, National Institute of Environmental Research), Joonyoung Ahn (National Institute of Environmental Research), J K Ahn (National Institute of Environmental Research), J Park (0000-0002-7755-4242, National Institute of Environmental Research), Jungmin Park (0000-0002-5837-2494, National Institute of Environmental Research), Minyoung Sung (National Institute of Environmental Research), Alan Fried (4Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA), AM Fried (Institute of Arctic and Alpine Research), Donald Blake (University of California, Irvine), William Brune (Pennsylvania State University), Samuel Hall (0000-0002-7335-6636, NSF National Center for Atmospheric Research), Glenn Diskin (Langley Research Center), Alex Guenther (0000-0001-6283-8288, University of California, Irvine), Jinsoo Park (0000-0002-5781-3796, National Institute of Environmental Research)
Year2026
Volume14
Issue1
Publication date2026-06-29
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenueElementa Science of the Anthropocene (JOURNAL)
Journal identifiersISSN: 2325-1026 • E-ISSN: 2325-1026
PublisherUniversity of California Press (PUBLISHER • US)
DOI10.1525/elementa.2025.00086
OpenAlexW7166651865
LanguageEN
References cited37

Despite notable reductions in precursor emissions, ambient ozone levels continue to increase in many urban areas, including Seoul, South Korea. This study examines the photochemical ozone production process in the Seoul Metropolitan Area using observational data from the Korea-United States Air Quality (KORUS-AQ) airborne campaign. By analyzing hydroxyl radical reactivity linked to nitrogen oxides (NOX) and volatile organic compounds (VOCs) (RNOx/RVOCs), we identify a shift from a NOX-saturated regime during the low-ozone period toward a transitional regime during the high-ozone period. Observed increases in VOC reactivity relative to NOX reactivity correlate with higher ozone production. We use a 0-D box model with observational constraints to generate ozone isopleths under different photochemical conditions. The results indicate that the isopleth varies significantly depending on atmospheric trace gas composition even in the same location with differences in trace gas mixtures, mostly driven by VOCs. RNOx/RVOCs generally correlate well with traditional metrics such as CH2O/NO2 and ozone production efficiency. However, the correlation becomes less reliable as the ozone production regime approaches the transitional regime. Our findings highlight the limitations of static regime classifications and emphasize the importance of dynamic, observation-based indicators for guiding ozone pollution control strategies

Air pollution · Air quality index · Atmospheric chemistry · Metropolitan area · Nitrogen oxides · NOx · Ozone · Reactivity (psychology) · Trace gas · Air Quality and Health Impacts · Atmospheric chemistry and aerosols · Plant responses to elevated CO2

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