In this work, the density functional and high-level ab initio theories are adopted to investigate the mechanisms and kinetics of reaction of (CH 3 ) 3 CC(O)X (X = F, Cl, and Br) with atomic chlorine. Rate coefficients for the reactions of chlorine atom with (CH 3 ) 3 CC(O)F ( k 1 ), (CH 3 ) 3 CC(O)Cl ( k 2 ), and (CH 3 ) 3 CC(O)Br ( k 3 ) are calculated using canonical variational transition state theory coupled with small curvature tunneling method over a wide range of temperatures from 250 to 1000 K. The dynamic calculations are performed by the variational transition state theory with the interpolated single-point energies method at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-311++G(d,p) level of theory. Computed rate constant is in good line with the available experimental value. The rate constants for the title reactions are in this order: k 1 < k 2 < k 3 , suggesting that the effect of halogen substitution on the mechanisms and dynamics is different. The subsequent and secondary reactions for the hydrogen abstraction intermediates are studied involving NO and O 2 molecules in the atmosphere. The atmospheric lifetime and global warming potential (GWP) of (CH 3 ) 3 CC(O)X (X = F, Cl, and Br) are estimated, and it shows that (CH 3 ) 3 CC(O)F have larger GWP value than that of (CH 3 ) 3 CC(O)Cl and (CH 3 ) 3 CC(O)Br. Due to the presence of Cl and Br atoms, the environmental impact of (CH 3 ) 3 CC(O)Cl and (CH 3 ) 3 CC(O)Br may be given more concerns. [ABSTRACT FROM AUTHOR]