CaltechAUTHORS
Published November 27, 2024 | Version Published
Journal Article Open

Fine Particle pH and Sensitivity to NH₃ and HNO₃ over South Korea During KORUS-AQ

Creators

  • 1. ROR icon Georgia Institute of Technology
  • 2. ROR icon Langley Research Center
  • 3. ROR icon University of Colorado Boulder
  • 4. ROR icon Cooperative Institute for Research in Environmental Sciences
  • 5. ROR icon Colorado State University
  • 6. ROR icon California Institute of Technology
  • 7. ROR icon University of New Hampshire
  • 8. ROR icon Ames Research Center
  • 9. ROR icon Aerodyne Research
  • 10. ROR icon École Polytechnique Fédérale de Lausanne

Abstract

Using a new approach that constrains thermodynamic modeling of aerosol composition with measured gas-to-particle partitioning of inorganic nitrate, we estimate the acidity levels for aerosol sampled in the South Korean planetary boundary layer during the NASA/NIER KORUS-AQ field campaign. The pH (mean ± 1σ = 2.43±0.68) and aerosol liquid water content determined were then used to determine the ‘chemical regime’ of the inorganic fraction of particulate matter (PM) sensitivity to ammonia and nitrate availability. We found that the aerosol formation is always sensitive to HNO3 levels, especially in highly polluted regions, while it is only exclusively sensitive to NH3 in some rural/remote regions. Nitrate levels are further promoted because dry deposition velocity is low and allows its accumulation in the boundary layer. Because of this, HNO3 reductions achieved by NOX controls prove to be the most effective approach for all conditions examined, and that NH3 emissions can only partially affect PM reduction for the specific season and region. Despite the benefits of controlling PM formation to reduce ammonium-nitrate aerosol and PM mass, changes in the acidity domain can significantly affect other processes and sources of aerosol toxicity (e.g. solubilization of Fe, Cu and other metals) as well as the deposition patterns of these trace species and reactive nitrogen.

Copyright and License

© 2024 Ifayoyinsola Ibikunle, Andreas Beyersdorf, Pedro Campuzano-Jost, Chelsea Corr, John D. Crounse, Jack Dibb, Glenn Diskin, Greg Huey, Jose-Luis Jimenez, Michelle J. Kim, Benjamin A. Nault, Eric Scheuer, Alex Teng, Paul O. Wennberg, Bruce Anderson, James Crawford, Rodney Weber, Athanasios Nenes. This work is licensed under a Creative Commons Attribution 4.0 International License. The material may not be used for commercial purposes.

Acknowledgement

This work was supported by NASA grant NNX16AE19G (KORUSAQ), from PyroTRACH (ERC-2016-COG) funded from H2020-EU.1.1. - Excellent Science - European Research Council (ERC), project ID 726165 and the Swiss National Science Foundation project 192292, Atmospheric Acidity Interactions with Dust and its Impacts (AAIDI). JLJ, PCJ, and BAN (AMS) were supported by NASA grants NNX15AT96G, 80NSSC19K0124, and 80NSSC18K0630. JDC, MKJ, AT, and POW (Caltech) were supported by NASA grants NNX15AT97G. The ISORROPIA-II thermodynamic equilibrium code is available at http://isorropia.epfl.ch. KORUS-AQ data is available at https://www-air.larc.nasa.gov/cgi-bin/ArcView/korusaq.

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Additional details

Identifiers

PMID
39618278

Funding

National Aeronautics and Space Administration
NNX16AE19G
European Research Council
726165
Swiss National Science Foundation
192292
National Aeronautics and Space Administration
NNX15AT96G
National Aeronautics and Space Administration
80NSSC19K0124
National Aeronautics and Space Administration
80NSSC18K0630
National Aeronautics and Space Administration
NNX15AT97G

Caltech Custom Metadata

Caltech groups
Division of Engineering and Applied Science (EAS), Division of Geological and Planetary Sciences (GPS)
Publication Status
Published