Relative rate techniques were used to determine k(Cl + C2F5H) = (2.93 +/- 0.23) x 10 (16), k(Cl + n-C4F9H) = (2.77 +/- 0.20) x 10 (16), k(OH + C2F5H) = (1.96 +/- 0.25) x 10 (15), and k(OH + n-C4F9H) = (1.85 +/-0.29) x 10 (15) cm(3) molecule (1) s (1) at 296 K. The reactivity of C2F5H and n-C4F9H was indistinguishable. Atmospheric lifetimes, radiative efficiencies, and global warming potentials (100 year horizon) of C2F5H and n-C4F9H were estimated as 31 years, 0.21 and 0.31W m (2) ppb (1), and 3280 and 2660, respectively. In the absence of NOx the chlorine-initiated oxidation of C2F5H and n-C4F9H gives perfluorocarboxylic acids in small (<2%) but detectable yields. (c) 2009 Elsevier B.V. All rights reserved.