Effect of the OH radical scavenger hydrogen peroxide on secondary organic aerosol formation from α-pinene ozonolysis

Abstract

Hydrogen peroxide (HOOH) is a potentially valuable hydroxyl radical (OH) scavenger in secondary organic aerosol experiments focused on ozonolysis yields. Here, we present results for α-pinene ozonolysis. The OH scavenging produces solely HO2 radicals and the resulting high [HO 2]/[RO2] ratio causes an increase in aerosol formation from α-pinene ozonolysis, compared to experiments performed with butanol OH scavengers. The majority of the increase comes in the 100 μg m -3 volatility range, suggesting that instead of more volatile products formed under higher RO2 conditions, less volatile, multifunctional hydroperoxides form under the high-HO2 conditions here. This dependence on the [HO2]/[RO2] ratio can be parameterized in a similar fashion to the way high- and low-NOx yields are currently treated in models. Copyright © American Association for Aerosol Research.