Preprints
https://doi.org/10.5194/egusphere-2025-6264
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/egusphere-2025-6264
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
09 Feb 2026
| 09 Feb 2026
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Wintertime photochemistry of acyl peroxynitrates and ozone in South Korea during the ASIA-AQ campaign
Abstract. Wintertime photochemical air pollution in East Asia remains poorly constrained despite its impact on regional air quality. Sources and formation pathways of acyl peroxynitrates (PANs) and ozone (O3), key photochemical products, are not well understood, hindering effective mitigation strategies. We investigate PANs and O3 over South Korea using observations from the ASIA-AQ campaign (February–March 2024). PANs reached 5.5 ppbv, strongly correlating with formaldehyde and particulate matter, indicating active winter photochemistry. Median PANs were higher in the mid-southern peninsula (MS; 987 pptv) and Yellow Sea (1197 pptv) than the Seoul Metropolitan Area (842 pptv). Elevated homologue-to-acetyl peroxynitrate ratios over the MS, with enhanced acryloyl peroxynitrate, acrolein, and ethylene oxide, provided tracers for petrochemical emissions and their impacts. Acetaldehyde contributed 53–80 % of PAN production. Ethanol was a major precursor of acetaldehyde (~50 %). Strong correlations (r² > 0.8) of ethanol and halocarbons indicate industrial and solvent sources under-represented in inventories. Formaldehyde and C2+ aldehydes contributed ~30 % to ozone production. Low ozone production efficiency (< 10) and radical termination dominated by nitric acid and PANs (> 80 %) indicate VOC-limited conditions. The fractional PANs contribution to NOx loss increased with decreasing OH reactivity ratio of NO2 to aldehydes, suggesting spatial increases in ozone production following NOx reductions. These findings demonstrate that a comprehensive understanding of VOC oxidation, particularly oxygenates from industrial sources, is essential for representing winter photochemistry. PANs measurements provide critical constraints on oxidation processes and their implications for emission control.
How to cite. Lee, Y. R., Arterburn, L., Takeuchi, M., Tanner, D. J., Roberts, J. M., Roozitalab, B., Jeong, D., Hills, A. J., Hornbrook, R. S., Apel, E. C., Meinardi, S., Barletta, B., Blake, N. J., Blake, D. R., Kim, S., Wojnowski, W., Piel, F., Wisthaler, A., Ball, K., Crounse, J. D., Wennberg, P. O., Miech, J., Choi, Y., DiGangi, J. P., Diskin, G. S., Sebol, A., Delaria, E. R., Hannun, R. A., St. Clair, J. M., Wolfe, G. M., Cho, C., Owen, C., Lesko, K., Franchin, A., Winstead, E. L., Ziemba, L. D., Moore, R., Wiggins, E. B., Symonds, G., Kim, D., Day, D. A., Campuzano-Jost, P., Jimenez, J. L., Ullmann, K., Hall, S. R., Crawford, J. H., and Huey, L. G.: Wintertime photochemistry of acyl peroxynitrates and ozone in South Korea during the ASIA-AQ campaign, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2025-6264, 2026.
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Status: open (until 23 Mar 2026)
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Young Ro Lee
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
Linda Arterburn
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
Masayuki Takeuchi
Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA
David J. Tanner
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
James M. Roberts
Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
Behrooz Roozitalab
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Daun Jeong
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
now at: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
now at: Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
Alan J. Hills
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Rebecca S. Hornbrook
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Eric C. Apel
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Simone Meinardi
Department of Chemistry, University of California, Irvine, CA, USA
Barbara Barletta
Department of Chemistry, University of California, Irvine, CA, USA
Nicola J. Blake
Department of Chemistry, University of California, Irvine, CA, USA
Donald R. Blake
Department of Chemistry, University of California, Irvine, CA, USA
Saewung Kim
Department of Earth System Science, University of California, Irvine, CA, USA
Wojciech Wojnowski
Department of Chemistry, University of Oslo, Oslo, Norway
Department of Analytical Chemistry, Gdańsk University of Technology, Gdańsk, Poland
Felix Piel
Department of Chemistry, University of Oslo, Oslo, Norway
Armin Wisthaler
Department of Chemistry, University of Oslo, Oslo, Norway
Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria
Katherine Ball
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
John D. Crounse
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
Paul O. Wennberg
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
Jason Miech
NASA Langley Research Center, Hampton, VA, USA
Oak Ridge Associated Universities, Oak Ridge, TN, USA
Yonghoon Choi
NASA Langley Research Center, Hampton, VA, USA
Analytical Mechanics Associates, Hampton, VA, USA
Joshua P. DiGangi
NASA Langley Research Center, Hampton, VA, USA
Glenn S. Diskin
NASA Langley Research Center, Hampton, VA, USA
Abby Sebol
Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD, USA
Erin R. Delaria
NASA Goddard Space Flight Center, Greenbelt, MD, USA
Reem A. Hannun
NASA Ames Research Center, Moffett Field, CA, USA
Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA, USA
Jason M. St. Clair
NASA Goddard Space Flight Center, Greenbelt, MD, USA
Joint Center for Earth Systems Technology, University of Maryland, Baltimore, MD, USA
Glenn M. Wolfe
NASA Goddard Space Flight Center, Greenbelt, MD, USA
Changmin Cho
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Courtney Owen
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Kirk Lesko
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Alessandro Franchin
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Edward L. Winstead
NASA Langley Research Center, Hampton, VA, USA
Luke D. Ziemba
NASA Langley Research Center, Hampton, VA, USA
Richard Moore
NASA Langley Research Center, Hampton, VA, USA
Elizabeth B. Wiggins
NASA Langley Research Center, Hampton, VA, USA
Guy Symonds
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
Department of Chemistry, University of Colorado, Boulder, CO, USA
Dongwook Kim
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
Department of Chemistry, University of Colorado, Boulder, CO, USA
Douglas A. Day
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
Department of Chemistry, University of Colorado, Boulder, CO, USA
Pedro Campuzano-Jost
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
Department of Chemistry, University of Colorado, Boulder, CO, USA
Jose L. Jimenez
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
Department of Chemistry, University of Colorado, Boulder, CO, USA
Kirk Ullmann
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
Samuel R. Hall
Atmospheric Chemistry Observations & Modeling Laboratory, NSF National Center for Atmospheric Research, Boulder, CO, USA
James H. Crawford
NASA Langley Research Center, Hampton, VA, USA
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
Short summary
We flew a large variety of instruments on the NASA DC-8 research aircraft to measure pollution over South Korea in the winter of 2024. This works focuses on acyl peroxynitrates (PANs for short) which are formed by chemistry in air. We found high levels of PANs often associated with industrial emissions of pollutants such as ethanol and ethylene oxide. This work helps to understand how to reduce pollution of this sort.
We flew a large variety of instruments on the NASA DC-8 research aircraft to measure pollution...