Fast generation of peroxides via atmospheric particulate photosensitization.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41032614.
- Also identified by DOI 10.1126/sciadv.adr8776 and PMC identifier 12487900.
- Licence recorded as CC BY-NC.
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Abstract
Peroxide species, including hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and organic peroxides, are key oxidants in shaping the atmospheric oxidative capacity. However, their formation pathways remain elusive under high-NO<sub>x</sub> conditions, where gas-phase mechanisms are suppressed. Herein, we report an "in-particle" peroxide formation pathway driven by photosensitization reactions in biomass burning organic aerosol. This mechanism remains highly efficient even in polluted, high-NO<sub>x</sub> environments, leading to orders-of-magnitude increase in particulate H<sub>2</sub>O<sub>2</sub> concentrations in the presence of sunlight than that expected from gas-phase partitioning. These findings suggest that intensifying wildfires in our warming world, beyond their primary emissions, may substantially alter the atmospheric oxidation chemistry and exacerbate air quality degradation.