Methyl bromide (CH3Br, b.pt. 3.6°C) is used as a soil fumigant to control insects and weeds. It is also a marine by-product. Photo dissociation of the C-Br bond produces Br atoms that can react with ozone similar to Cl, except more effectively. Do you expect CH3Br to be photolyzed in the troposphere? The bond enthalpy of the C-Br bond is about 293 kJ/mol.