A number that refers to the amount of ozone depletion caused by a substance. The ODP is the ratio of the impact on ozone of a chemical compared to the impact of a similar mass of chlorofluorocarbon (CFC)-11. Thus, the ODP of CFC-11 is 1.0. Other CFCs and hydrochlorofluorocarbon have ODPs that range from 0.01 to 1.0. Halon ODPs peak at 10. Carbon tetrachloride has an ODP of 1.2, and methyl chloroform's ODP is 0.11. Hydrofluorocarbons have zero ODP because they do not contain chlorine.
The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane (R-11) being fixed at an ODP of 1.0. Chlorodifluoromethane (R-22), for example, has an ODP of 0.05.