Dr. Kangwei Li and co-workers at the Department of Environmental Sciences at the University of Basel have developed a novel analytical method for the detailed characterization of organic peroxides—a health-relevant but rarely explored compound family in atmospheric aerosols. This new method significantly expands the molecular-level understanding of organic peroxides in atmospheric aerosols. Through this method, more than 300 organic peroxides have been identified individually in aerosol particles. This work also developed a method to determine the oxidizing reactivity of these organic peroxides, a property that might be directly linked to the toxicity of these compounds and of air pollution particles as a whole. This study represents a fundamental step for investigating the formation chemistry, reactivity, and health impact of organic peroxides in atmospheric aerosol particles. This work was led by Dr. Kangwei Li and was awarded the Swiss Aerosol Award 2025.
It has been suggested that organic peroxides, a major and reactive compound class in secondary organic aerosol (SOA), can significantly contribute to aerosol toxicity and related health effects and therefore are considered as health-relevant components in aerosol particles. Despite their atmospheric and health importance, the analytical-chemical identification and characterization of specific organic peroxides in atmospheric aerosols is highly challenging and uncertain and therefore it is not clear from which pollution sources these peroxides originate. However, only a clear understanding how these peroxides form in the atmosphere and from which particle sources they are emitted will allow to design specific and effective control policies to decrease the concentration of these harmful components in the atmosphere.
A novel analytical method has been developed for the molecular characterization of organic peroxides in organic aerosol particles, using state-of-the-art analytical-chemical instrumentation. More than 300 organic peroxides have been identified in organic aerosol particles, showing a wide range of reactivities with iodide. The awarded research significantly improves the molecular-level identification and understanding of organic peroxides in SOA. The newly developed method will allow in the future to improve our understanding of these compounds which are likely highly relevant for the toxicity of air pollution particles. Overall, this work highlights the importance of molecular understanding of organic peroxides and their toxicity and health impact in atmospheric aerosols. The Swiss Aerosol Award will be/was presented on 3 November 2025 at the 20th meeting of the Swiss Aerosol Group (SAG). The prize is endowed with CHF 5 000.
Information:
- Dr. Kangwei Li, Postdoc, Atmosphere Sciences Group, Department of Environmental Sciences, University of Basel,
Original title: Molecular Composition of Organic Peroxides in Secondary Organic Aerosols Revealed by Peroxide-Iodide Reactivity; Source: https://doi.org/10.1021/acs.est.5c03241
Press Summary: 
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