Kinetics of the OH Reaction with Methyl Chloroform and Its Atmospheric Implications

The rate coefficients for the reaction of hydroxyl (OH) radicals with methyl chloroform (CH3CCI3) were measured between 243 and 379 kelvin with the pulsed photolysis—laserinduced fluorescence method. The measured rate coefficients at 298 and 277 kelvin were ∼20 and ∼15%, respectively, lower than earlier values. These results will increase the tropospheric OH concentrations derived from the CH3CCI3 budget analysis by ∼15%. The predicted atmospheric lifetimes of species whose main loss process is the reaction with OH in the troposphere will be lowered by 15% with consequent changes in their budgets, global warming potentials, and ozone depletion potentials.