Development of iron-mediated molecular chlorine chemistry in GEOS-Chem: model description, evaluation and global atmospheric implication

Chen, Jing; Sun, Xianyi; Qin, Chuang; Li, Jie; Chen, Qianjie; Fu, Xiao

doi:10.5194/acp-26-9809-2026

Articles | Volume 26, issue 13

https://doi.org/10.5194/acp-26-9809-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-26-9809-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 26, issue 13

Research article

|

13 Jul 2026

Research article |

| 13 Jul 2026

Development of iron-mediated molecular chlorine chemistry in GEOS-Chem: model description, evaluation and global atmospheric implication

Jing Chen, Xianyi Sun, Chuang Qin, Jie Li, Qianjie Chen, and Xiao Fu

Supplement

https://doi.org/10.5194/acp-26-9809-2026-supplement

Model code and software

Modified GEOS-Chem source-code files for iron dissolution and iron-mediated molecular chlorine formation Jing Chen https://doi.org/10.5281/zenodo.20529218

geoschem/geos-chem: GEOS-Chem (science codebase) 14.2.3 Bob Yantosca et al. https://doi.org/10.5281/zenodo.10246546

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Short summary

By incorporating an iron-mediated molecular chlorine (Cl₂) formation pathway into the GEOS-Chem global atmospheric chemistry transport model, simulated surface Cl₂ concentrations align better with observations. Reactive chlorine species increase substantially, thereby altering atmospheric oxidative capacity. Stronger oxidation elevates PM_2.5 levels in polluted regions, especially in winter, underscoring the need to consider iron–halogen coupling chemistry in future air-quality mitigation.