Molecular rearrangement of bicyclic peroxy radicals is a key route to aerosol from aromatics

Siddharth Iyer, Avinash Kumar, Anni Savolainen, Shawon Barua, Christopher Daub, Lukas Pichelstorfer, Pontus Roldin, Olga Garmash, Prasenjit Seal, Theo Kurtén, Matti Rissanen

Research output: Contribution to journalArticleScientificpeer-review


The oxidation of aromatics contributes significantly to the formation of atmospheric aerosol. Using toluene as an example, we demonstrate the existence of a molecular rearrangement channel in the oxidation mechanism. Based on both flow reactor experiments and quantum chemical calculations, we show that the bicyclic peroxy radicals (BPRs) formed in OH-initiated aromatic oxidation are much less stable than previously thought, and in the case of the toluene derived ipso-BPRs, lead to aerosol-forming low-volatility products with up to 9 oxygen atoms on sub-second timescales. Similar results are predicted for ipso-BPRs formed from many other aromatic compounds. This reaction class is likely a key route for atmospheric aerosol formation, and including the molecular rearrangement of BPRs may be vital for accurate chemical modeling of the atmosphere.

Original languageEnglish
Article number4984
JournalNature Communications
Issue number1
Publication statusPublished - 2023
Publication typeA1 Journal article-refereed

Publication forum classification

  • Publication forum level 3

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)


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