Atmospheric oxidation of hydrocarbons.

Hydrocarbon oxidation in the atmosphere proceeds generally by the following sequence of reactions: hydrocarbon + OH----alkyl radical + H2O, alkyl radical + O2 (3 sigma)----alkylperoxy radical, alkylperoxy radical + NO----alkoxy radical + NO2, alkoxy radical + O2 (3 sigma)----aldehyde + HO2. The atmospheric lifetimes of hydrocarbons are determined by their reactivity towards OH as well as by the average OH concentration level. They are compound specific and vary from several hours to several years. Hydrocarbon oxidation chains couple with other trace gases (Ox, HOx and NOx). For the conditions of the average continental atmosphere an increase of the oxidative potential (HOx, Ox) is predicted through hydrocarbon oxidation.