Articles | Volume 25, issue 23
https://doi.org/10.5194/acp-25-18093-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-25-18093-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
10 Dec 2025
Research article |
| 10 Dec 2025
| 10 Dec 2025
Modeling atmospheric sulfate oxidation chemistry via the oxygen isotope anomaly using the Community Multiscale Air Quality Model (CMAQ)
Huan Fang
Department of Chemistry and Biochemistry, University of South Carolina, SC, 631 Sumter Street Columbia, SC 29208, United States
Department of Chemistry and Biochemistry, University of South Carolina, SC, 631 Sumter Street Columbia, SC 29208, United States
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A new emission input dataset that incorporates nitrogen isotopes has been used in the CMAQ (Community Multiscale Air Quality) modeling system simulation to qualitatively analyze the changes in δ15N values, due to the dispersion, mixing, and transport of the atmospheric NOx emitted from different sources. The dispersion, mixing, and transport of the atmospheric NOx were based on the meteorology files generated from the WRF (Weather Research and Forecasting) model.
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A new emission input dataset that incorporates nitrogen isotopes has been used in the CMAQ (Community Multiscale Air Quality) modeling system simulation to qualitatively analyze the changes in δ15N values, due to the dispersion, mixing, and transport of the atmospheric NOx emitted from different sources. The dispersion, mixing, and transport of the atmospheric NOx were based on the meteorology files generated from the WRF (Weather Research and Forecasting) model.
Jiajue Chai, Jack E. Dibb, Bruce E. Anderson, Claire Bekker, Danielle E. Blum, Eric Heim, Carolyn E. Jordan, Emily E. Joyce, Jackson H. Kaspari, Hannah Munro, Wendell W. Walters, and Meredith G. Hastings
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Nitrous acid (HONO) derived from wildfire emissions plays a key role in controlling atmospheric oxidation chemistry. However, the HONO budget remains poorly constrained. By combining the field-observed concentrations and novel isotopic composition (N and O) of HONO and nitrogen oxides (NOx), we quantitatively constrained the relative contribution of each pathway to secondary HONO production and the relative importance of major atmospheric oxidants (ozone versus peroxy) in aged wildfire smoke.
Huan Fang, Wendell W. Walters, David Mase, and Greg Michalski
Geosci. Model Dev., 14, 5001–5022, https://doi.org/10.5194/gmd-14-5001-2021, https://doi.org/10.5194/gmd-14-5001-2021, 2021
Short summary
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A new photochemical reaction scheme that incorporates nitrogen isotopes has been developed to simulate isotope tracers in air pollution. The model contains 16 N compounds, and 96 reactions involving N used in the Regional Atmospheric Chemistry Mechanism (RACM) were replicated using 15N in a new mechanism called iNRACM. The model is able to predict d15N variations in NOx, HONO, and HNO3 that are similar to those observed in aerosol and gases in the troposphere.
Huan Fang and Greg Michalski
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2020-322, https://doi.org/10.5194/gmd-2020-322, 2020
Publication in GMD not foreseen
Short summary
Short summary
A new emission input dataset that incorporates nitrogen isotopes has been developed to simulate isotope tracers in air pollution. The NOx emission from different sources simulated by Sparse Matrix Operator Kerner Emissions (SMOKE) were replicated using 15N. The dataset is able to predict δ15N variations in NOx that are similar to those observed in aerosol and gases in the troposphere.
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Short summary
The Sulfur Tracking Mechanism (STM) in Community Multiscale Air Quality Model (CMAQ) was used to model the oxygen isotope anomaly (Δ17O) of aerosol sulfate (ASO4) within the contiguous United States over full annual cycles, for the first time at this spatial and temporal coverage. This approach allows for a qualitative analysis of sulfate (SO42-) formation processes and comparison with corresponding measurements.
The Sulfur Tracking Mechanism (STM) in Community Multiscale Air Quality Model (CMAQ) was used to...
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