OH production from the photolysis of isoprene-derived peroxy radicals: cross-sections, quantum yields and atmospheric implications.

In environments with high concentrations of biogenic volatile organic compounds and low concentrations of nitrogen oxides (NO = NO + NO), significant discrepancies have been found between measured and modeled concentrations of hydroxyl radical (OH). The photolysis of peroxy radicals from isoprene (HO-Iso-O) in the near ultraviolet represents a potential source of OH in these environments, yet has not been considered in atmospheric models. This paper presents measurements of the absorption cross-sections for OH formation (σ) from the photolysis of HO-Iso-O at wavelengths from 310-362.