Largely underestimated production of isoprene epoxydiols (IEPOX) through high-NO oxidation pathways in urban areas
Abstract Isoprene is the dominant nonmethane volatile organic compound (VOC) emitted into the atmosphere globally, with important atmospheric chemistry impacts on air quality and climate. One crucial intermediate in its gas-phase oxidation is isoprene epoxydiol (IEPOX), which contributes significantly to the formation of secondary organic aerosols (SOA). It is generally accepted that IEPOX is efficiently formed in remote forested regions with a sufficiently low NO/HO 2 ratio. Here, we show that the oxidation of isoprene hydroxynitrates (IHN) can be an alternative, efficient, NO-driven pathway leading to the formation of IEPOX in urban areas where moderate to high NO concentrations exist. Field measurements from the megacity of Beijing show that this pathway contributes to more than 50% of IEPOX production during the morning and early afternoon. The results improve our understanding of the NO x dependence of SOA formation in polluted areas, where anthropogenic emissions can significantly enhance biogenic SOA formation.
Authors
- Andrew R. Rickard (ORCID: https://orcid.org/0000-0003-2203-3471)
- Sainan Wang (ORCID: https://orcid.org/0000-0002-5759-1484)
- Weiwei Hu (ORCID: https://orcid.org/0000-0002-3485-6304)
- Thomas J. Bannan (ORCID: https://orcid.org/0000-0002-1760-6522)
- Xiaoling Zhang (ORCID: https://orcid.org/0000-0002-5557-5317)
- Jacqueline F. Hamilton (ORCID: https://orcid.org/0000-0003-0975-4311)
- Carl J. Percival (ORCID: https://orcid.org/0000-0003-2525-160X)
- Mike J. Newland (ORCID: https://orcid.org/0000-0003-4529-3874)
- Freya Squires (ORCID: https://orcid.org/0000-0002-3364-4617)
- Archit Mehra (ORCID: https://orcid.org/0000-0002-4273-8199)
- Wei Song (ORCID: https://orcid.org/0000-0002-8512-0663)
- Xinming Wang (ORCID: https://orcid.org/0000-0002-1982-0928)
- Chen Yang (ORCID: https://orcid.org/0000-0001-6388-637X)
- Liming Wang (ORCID: https://orcid.org/0000-0002-8953-250X)
Institutions
- Chinese Academy of Sciences (CN)
- Chengdu University of Information Technology (CN)
- University of Manchester (GB)
- Guangzhou Institute of Geochemistry (CN)
- National Centre for Atmospheric Science (GB)
- Chongqing Institute of Green and Intelligent Technology (CN)
- University of York (GB)
- South China University of Technology (CN)
Publication Details
- Journal
- npj Climate and Atmospheric Science
- Published
- 2025-07-05
- DOI
- https://doi.org/10.1038/s41612-025-01151-4
- Primary Topic
- Atmospheric chemistry and aerosols
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- University of Leeds
- National Natural Science Foundation of China
- State Key Laboratory of Organic Geochemistry
- Guangzhou Municipal Science and Technology Bureau
- Medical Research Council
- Natural Environment Research Council
- National Key Research and Development Program of China