Rate coefficients for the reactions of hydroxyl radicals with ethyl vinyl ketone and vinyl propionate were determined at 298 K and atmospheric pressure. A collapsible chamber with gas chromatography was used to perform relative kinetic determinations. The room temperature rate coefficients (in cm(3) molecule (1) s (1)) were: k(1)(OH + CH2=CHC(O)CH2CH3) = (2.90 +/- 0.79) x 10 (11) and k(2)(OH + CH2= CHOC(O)CH2CH3) = (2.46 +/- 0.28) x 10 (11). This is the first kinetic study of title reactions under atmospheric conditions. The kinetic data were compared with previous literature values, used to calculate atmospheric lifetimes and correlated with the ionization potential of the unsaturated compounds. (C) 2010 Elsevier B.V. All rights reserved.