Neftel, A.A.NeftelJacob, P.P.JacobKlockow, D.D.Klockow2024-09-022024-09-021984https://boris-portal.unibe.ch/handle/20.500.12422/43012Hydrogen peroxide, a powerful oxidant, is believed to be a key component in the oxidation of SO2 to H2SO4 in clouds1. The first quantitative H2O2 measurements in snow, rain, hoarfrost and fog were reported in 1874 (ref. 2), however, systematic investigations of H2O2 concentrations in precipitation and hydrometeors began only a few years ago3,4. We report here measurements of hydrogen peroxide in polar ice samples. To our knowledge, chemically-reactive species have not been previously analysed in ice core samples. Our measurements show that H2O2 is a dominant trace compound present in clouds over remote and clean areas.en500 - Science::530 - Physicsarticle10.48350/15825310.1038/311043a0