Kinetic studies of the OH-inititated reactions of selected alcohols in the presences of fine aerosols: Effects of aerosol composition

Organic compounds in the troposphere are capable of reacting with O ₃, OH radicals, and NO ₃ radicals. However, the reaction with OH radicals is the major gas-phase atmospheric loss process for hydrocarbons in the daytime. A study was carried out to determine the effects of atmospheric aerosols on the gas-phase reactions of OH radicals with methanol, ethanol, and 1-propanol, and to determine which aerosol constituent(s) has the most profound effect on the kinetics of the OH/alcohol reaction. There was no significant difference between data obtained in the presence vs. the absence of NO. Ammonium sulfate aerosols were the only aerosols that affected the relative rate of 1-propanol/p-xylene/OH system in the presence of the lower aerosol surface area. However, once the available surface area was approximately doubled, ammonium nitrate and ammonium chloride aerosols also affected the relative rate for 1-propanol vs. p-xylene. The ammonium ion was the dominant ion influencing the relative rate constant for the 1-propanol system. The influences of aerosols on the kinetics of 1-propanol/•OH reaction depended on both the composition and concentration of aerosols.