Exergetic pollution potential: Estimating the revocability of chemical pollution

Abstract

The waste exergy approach to quantitative comparison of environmental impacts is considerably improved by proposing a separate accounting of material and energetic waste exergy and the implications are discussed within the context of sustainability. The exergy of mixing of a waste stream is found to be particularly well suited to an exergetic definition of chemical pollution and a correlative relationship with environmental pollutant cost (EPC) is suggested. A comprehensive measure of chemical environmental impact called pollution potential is defined as temperature multiplied by the change in configurational entropy per mole of pollutant in the environment. The result is related to the ideal thermodynamic work of chemical separation per mole required to instantaneously revoke a chemical pollutant, thereby returning the environment to a pristine reference condition. The current pollution potentials and total exergy of revocation of several notable atmospheric pollutants are estimated. Carbon dioxide is found to have low pollution potential in comparison to most halogenated hydrocarbons, but the vast quantities of anthropogenic carbon dioxide in the atmosphere would require much more total exergy of separation to revoke.