Interstitial Aerosol Water Uptake Limits Fog Supersaturation
Abstract Fogs over polluted regions often exhibit extremely low supersaturation, yet the controlling mechanisms remain poorly constrained. Existing frameworks attribute supersaturation adjustment mainly to competition among activated droplets, while the role of interstitial aerosol water has been largely overlooked due to observational limitations. Here, we develop a new approach based on an advanced optical instrument to achieve online, size‐resolved quantification of interstitial aerosol water uptake. By combining optical measurements with a machine learning–constrained framework, we retrieve dry aerosol volume and hygroscopic growth at saturation of interstitial aerosols, enabling fog water budget analysis. Observations on the North China Plain show that interstitial aerosol water contributes >50% of total fog water during formation and remains comparable (>25%) to droplet water throughout evolution. This competition helps suppress the supersaturation to <0.03%, limiting aerosol activation and droplet growth. These results identify interstitial aerosol water as a key regulator of fog supersaturation in polluted atmospheres.
Authors
- Nan Ma (ORCID: https://orcid.org/0000-0003-4494-3337)
- Wanyun Xu (ORCID: https://orcid.org/0000-0003-4787-1754)
- Qingwei Zeng (ORCID: https://orcid.org/0000-0002-2285-466X)
- Defeng Zhao (ORCID: https://orcid.org/0000-0002-8790-7283)
- Ru‐Jin Huang (ORCID: https://orcid.org/0000-0002-4907-9616)
- Yele Sun (ORCID: https://orcid.org/0000-0003-2354-0221)
- Yuxuan Bian (ORCID: https://orcid.org/0000-0002-5846-417X)
- Mengxiang Hou
- Ye Kuang (ORCID: https://orcid.org/0000-0003-4813-9784)
- Li Liu (ORCID: https://orcid.org/0009-0009-5912-4255)
- Gang Zhao (ORCID: https://orcid.org/0000-0001-7160-4600)
- Mingwei Li (ORCID: https://orcid.org/0000-0002-1896-3484)
- Jiangchuan Tao (ORCID: https://orcid.org/0009-0007-7118-8070)
- Qiqi Mo (ORCID: https://orcid.org/0009-0007-0040-0177)
- Miaomiao Zhai (ORCID: https://orcid.org/0000-0001-9745-8410)
- Fengling Yuan
- Weiqi Xu (ORCID: https://orcid.org/0000-0003-0873-6728)
- Weihong Huang
- Tianxu Chen
- Qi Liu
- Lei Liu
- Qingpeng Meng
- Yujing Pan
- Xingyu Liu
- Hanbing Xu
Institutions
- China Meteorological Administration (CN)
- Minzu University of China (CN)
- Sun Yat-sen University (CN)
- Jinan University (CN)
- National University of Defense Technology (CN)
- Chinese Academy of Sciences (CN)
- Fudan University (CN)
- Chinese Academy of Meteorological Sciences (CN)
- Institute of Atmospheric Physics (CN)
- Institute of Earth Environment (CN)
- State Key Laboratory of Severe Weather (CN)
- Institute of Tropical and Marine Meteorology, China Meteorological Administration (CN)
Publication Details
- Journal
- Geophysical Research Letters
- Published
- 2026-11-08
- DOI
- https://doi.org/10.1029/2026gl123841
- Primary Topic
- Atmospheric aerosols and clouds
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Natural Science Foundation of China
- Basic and Applied Basic Research Foundation of Guangdong Province