Sulfate formation through copper-catalyzed SO2 oxidation by NO2 at aerosol surfaces
Abstract Severe urban air pollution in China is driven by a synergistic conversion of SO 2 , NOx, and NH 3 into fine particulate matter (PM 2.5 ). Field studies indicated NO 2 as an important oxidizer to SO 2 in polluted atmospheres with low photochemical reactivity, but this rapid reaction cannot be explained by the aqueous reactive nitrogen chemistry in acidic urban aerosols. Here, using an aerosol optical tweezer and Raman spectroscopy, we show that the multiphase SO 2 oxidation by NO 2 is accelerated for two-order-of-magnitude by a copper catalyst. This reaction occurs on aerosol surfaces, is independent of pH between 3 and 5, and produces sulfate by a rate of up to 10 µg m -3 air hr -1 when reactive copper reaches a millimolar concentration in aerosol water – typical of severe haze events in North China Plain. Since copper and NO 2 are companion emitters in air pollution, they can act synergistically in converting SO 2 into sulfate in China’s haze.
Authors
- Xiyuan Kang
- Shufeng Pang (ORCID: https://orcid.org/0000-0002-4934-3288)
- Qishen Huang (ORCID: https://orcid.org/0000-0002-8493-5799)
- Xiaowu Zhang (ORCID: https://orcid.org/0000-0001-6180-1184)
- Pai Liu (ORCID: https://orcid.org/0000-0003-2227-9762)
- Yunhong Zhang (ORCID: https://orcid.org/0000-0002-2899-5068)
- Yuxin Liu (ORCID: https://orcid.org/0000-0002-5388-9988)
- Zhe Chen (ORCID: https://orcid.org/0000-0002-1427-8770)
- Weigang Wang (ORCID: https://orcid.org/0000-0001-6911-1110)
- Linfang Li (ORCID: https://orcid.org/0000-0002-6350-6442)
- Min Zhong (ORCID: https://orcid.org/0000-0003-4151-4633)
- Jiayi Yin
- Xinyue Chao
- Maofa Ge (ORCID: https://orcid.org/0000-0002-1771-9359)
Institutions
- Beijing Institute of Technology (CN)
- Beijing National Laboratory for Molecular Sciences (CN)
- Beijing University of Chemical Technology (CN)
Publication Details
- Journal
- npj Climate and Atmospheric Science
- Published
- 2025-02-18
- DOI
- https://doi.org/10.1038/s41612-025-00934-z
- Citations
- 5
- Primary Topic
- Atmospheric chemistry and aerosols
- Type
- article
- Field-Weighted Citation Impact
- 6.50
Funders
- University of Bristol
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- Jinan University
- Beijing Institute of Technology
- Institute of Atmospheric Physics, Chinese Academy of Sciences
- Beijing Institute of Technology Research Fund Program for Young Scholars
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences