From AMS Glossary
The hydroperoxyl radical is a chain carrier in the atmosphere and in combustion systems. In the stratosphere, it is involved in ozone-destroying chain reactions. In the troposphere, it is formed as an intermediate in the oxidation of most hydrocarbons.
Bate, D. R., and M. Nicolet 1950. The photochemistry of atmospheric water vapor. J. Geophys. Res.. 55. p. 301.