The pulse radiolysis of SF 6 /CH 3 SCH 3 /O 2 /NO 2 gas mixtures was used to generate CH 3 SCH 2 O 2 radicals in the presence of NO 2 . By monitoring the rate of NO 2 decay using its absorption at 400 nm, rate constants for the reaction of CH 3 SCH 2 O 2 radicals with NO 2 were measured to be (9.2 ± 0.9) 10 - 1 2 and (7.1 ± 0.9) 10 - 1 2 cm 3 molecule - 1 s - 1 at room temperature in 1000 and 300 mbar of SF 6 diluent, respectively. Results are discussed with respect to the atmospheric chemistry of dimethyl sulfide.