AbstractThe rate constants for reactions of OH with ClCH2CH2Cl, Cl2CHCHCl2, BrCH2CH2Br, CH3CH2Br have been measured by using a discharge flow‐resonance fluorescence (DF‐RF) technique over the temperature range 293–418 K. The rate constants as a function of temperature were fitted to the Arrhenius expression as follows: (k's units are 10−12cm3molecule−1s−1, and Ea's units are cal/mol)\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm OH} + {\rm ClCH}_2 {\rm CH}_2 {\rm Cl}:} & {k_1 = (8.91 \pm 1.63)^ \ast {\rm EXP}((-2164.5 \pm 119.9)/RT)}\\[10pt] {{\rm OH} + {\rm BrCH}_2 {\rm CH}_2 {\rm Br}:} & {k_2 = (14.36 \pm 2.70)^ \ast {\rm EXP}((- 2521.4 \pm 123.5)/RT)}\\[10pt] {{\rm OH} + {\rm Cl}_2 {\rm CHCHCl}_2:} & {k_3 = (5.01 \pm 0.89)^ \ast {\rm EXP}((- 1825.8 \pm 116.7)/RT)} \\[10pt] {{\rm OH} + {\rm CH}_3 {\rm CH}_2 {\rm Br}:} & {k_4 = (23.45 \pm 4.62)^ \ast {\rm EXP}((- 2558.2 \pm 124.1)/RT)}\end{array} $$\end{document}The experimental data have been compared with theoretical calculations of the semi‐empirical BEBO‐transition state method. Life‐times of the four haloethanes in the troposphere ha