ATMOSPHERIC LIFETIME, ITS APPLICATION AND ITS DETERMINATION - CFC-SUBSTITUTES AS A CASE-STUDY

The concept of atmospheric lifetime, its application in atmospheric ch emistry, and its use in defining environmental acceptability indices s uch as the ozone depletion potential and the global warming potential are described. The determination of the atmospheric lifetime from labo ratory measured chemical kinetic and photochemical parameters is highl ighted. A brief description of the laboratory methods used to determin e kinetic parameters and the difficulties encountered in measuring the m are given. In all these descriptions and discussions, chlorofluoroca rbons (CFCs) and their substitutes are used as examples. The environme ntal acceptability of the currently proposed CFC substitutes, the hydr ochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are discuss ed. Lastly, the question is raised: Should atmospheric lifetime be use d as an index of accept ability?