The atmospheric lifetimes of CFC 11 and CFC 12

Abstract

A two‐dimensional (2‐D) chemical model of the atmosphere is used to investigate the stratospheric removal rates of the Chlorofluorocarbons CFC 11 (CFCl 3 ) and CFC 12 (CF 2 Cl 2 ). Assuming equivalent vertical transport rates, one‐dimensional (1‐D) models are shown to overestimate the atmospheric lifetime of CFC 11 by ∼10% because of their neglect of latitudinal effects. The present Du Pont 1‐D and 2‐D models have somewhat different effective transport rates and give steady state CFC 11 atmospheric lifetimes of 75 and 60 years, respectively, assuming no tropospheric destruction mechanism. For CFC 12, the corresponding calculated lifetimes are 140 and 120 years.