The model simulates the 5-year record of observations made at the five ALE sampling sites to generally within ±5% of the observed mean. The calculated average global lifetime of methyl chloroform is 5.7±0.3 yrs. The estimated global mean OH concentration is 6.5±0.4×105 cm-3. However, the inclusion of the ocean sink does not significantly improve the simulation of the observed interhemispheric gradient of methyl chloroform. Atmospheric transport dominates the simulated CH3CCl3 seasonal cycle throughout the northern hemisphere but is less important in the southern hemisphere. -from Authors