Smog chambers equipped with FTIR spectrometers were used to study the Cl atom and OH radical initiated oxidation of CH 3 O(CF 2 CF 2 O) n CH 3 (n = 1-3) in 720 ′ 20 Torr of air at 296 ′ 3 K. Relative rate techniques were used to measure k(Cl + CH 3 O(CF 2 CF 2 O) n CH 3 ) = (3.7 ′ 0.7) x 10 - 1 3 and k(OH + CH 3 O(CF 2 CF 2 O) n -CH 3 ) = (2.9 ′ 0.5) × 10 - 1 4 cm 3 molecule - 1 s - 1 leading to an estimated atmospheric lifetime of 2 years for CH 3 O(CF 2 CF 2 O) n CH 3 . The Cl initiated oxidation of CH 3 O(CF 2 CF 2 O) n CH 3 in air diluent gives CH 3 O(CF 2 CF 2 O) n C(O)H in a yield which is indistinguishable from 100%. Further oxidation leads to the diformate, H(O)CO(CF 2 CF 2 O) n C(O)H. A rate constant of k(Cl + CH 3 O(CF 2 CF 2 O) n CHO) = (1.81 ′ 0.36) × 10 - 1 3 cm 3 molecule - 1 s - 1 was determined. Quantitative infrared spectra for CH 3 O(CF 2 CF 2 O) n CH 3 (n = 1-3) were recorded and used to estimate halocarbon global warming potentials of 0.051, 0.058, and 0.055 (100 year time horizon, relative to CFC-11) for CH 3 OCF 2 CF 2 OCH 3 , CH 3 O(CF 2 CF 2 O) 2 CH 3 , and CH 3 C(CF 2 CF 2 O) 3 -CH 3 , respectively. Results are discussed with respect to the atmospheric chemistry of hydrofluoropolyethers (HFPEs).