Highly oxidized products from the atmospheric reaction of hydroxyl radicals with isoprene.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40021649.
- Also identified by DOI 10.1038/s41467-025-57336-1 and PMC identifier 11871199.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Isoprene (C<sub>5</sub>H<sub>8</sub>) globally accounts for half of the non-methane hydrocarbon flux into Earth´s atmosphere. Its degradation is mainly initiated by the gas-phase reaction with OH radicals yielding a complex system of RO<sub>2</sub> radicals. Subsequent product formation is not conclusively understood yet. Here we report the observation of C<sub>4</sub>- and C<sub>5</sub>-products from OH + isoprene bearing at least two functional groups. Their production is initiated either by the reaction of initially formed δ-RO<sub>2</sub> radicals with NO or by 1,6 H-shift isomerization of Z-δ-RO<sub>2</sub> radicals. Both reaction channels also form highly oxygenated molecules (HOMs), which could be important for the generation of secondary organic aerosol. C<sub>5</sub>H<sub>9</sub>O<sub>8</sub> and C<sub>5</sub>H<sub>9</sub>O<sub>9</sub> radicals represent the main precursors of closed-shell HOMs. Global simulations revealed that the isoprene-derived HOM-RO<sub>2</sub> production is comparable with that of α-pinene, currently regarded as very important HOM source. This study provides a more complete insight into isoprene´s degradation process including the HOM formation.