Ozone depletion and global warming potentials of CF3I

Abstract

Laboratory measurements of the infrared and near‐ultraviolet absorption characteristics of CF 3 I (a potentially useful substitute for halons) are presented. Using these data together with a detailed photochemical model, it is shown that the lifetime of this gas in the sunlit atmosphere is less than a day. The chemistry of iodine in the stratosphere is evaluated, and it is shown that any iodine that reaches the stratosphere will be very effective for ozone destruction there. However, the extremely short lifetime of CF 3 I greatly limits its transport to the stratosphere when released at the surface, especially at midlatitudes, and the total anthropogenic surface release of CF 3 I is likely to be far less than that of natural iodocarbons such as CH 3 I on a global basis. It is highly probable that the steady‐state ozone depletion potential (ODP) of CF 3 I for surface releases is less than 0.008 and more likely below 0.0001. Measured infrared absorption data are also combined with the lifetime to show that the 20‐year global warming potential (GWP) of this gas is likely to be very small, less than 5. Therefore this study suggests that neither the ODP nor the GWP of this gas represent significant obstacles to its use as a replacement for halons.