EVALUATING THE ENVIRONMENTAL-IMPACT OF PRODUCTS AND PRODUCTION PROCESSES - A COMPARISON OF 6 METHODS

The desire of environmentally-conscious consumers and manufacturers to choose more environmentally benign products and processes has led to the development of life cycle assessment (LCA) and design for environm ent (DfE). In both of these areas, attention has focused initially on the development of inventories of emissions and raw materials consumpt ion for particular products and processes. A number of methods for the comparison and evaluation of an inventory's dissimilar pollution load s and resource demands have been proposed, but no satisfactory solutio n has yet been identified. This paper compares the structure and prope rties of six different methods. The health hazard scoring (HHS) system uses the analytical hierarchy process (AHP) to weight workplace toxic effects and accident risks. The material input per service-unit (MIPS ) aggregates the mass of all the material input required to produce a product or service, The Swiss eco-point (SEP) method scores pollutant loadings based on a source's contribution to an acceptable total pollu tion load and an environmental scarcity factor. The sustainable proces s index (SPI) determines the area that would be required to operate a process sustainably, based on renewable resource generation and toxic degradation; an extension of the dilution volume approach, The Society of Environmental Toxicology and Chemistry's life-cycle impact assessm ent (SETAC LCA) impact assessment method aggregates pollutants with si milar impacts to equivalency potentials (measured in kg CO2 equivalent , kg benzene equivalent etc.) and uses decision analysis to assign wei ghts to different adverse impacts. The environmental priority system ( EPS) characterizes the environmental damage caused by equivalency pote ntials and expresses it in monetary terms, derived from environmental economics. Despite their use for the same purposes, the six methods di ffer in what they try to achieve, in the effects they consider, in the depth of analysis, in the way values influence the final score, and i n use of ordinal or cardinal measures of impact. Two problem areas are identified: (1) to varying degrees, each of the methods has the poten tial to recommend an alternative that actually has a higher impact tha n other alternatives; (2) for some of the methods the data requirement is so extensive and the tolerance of imperfect data is so low that th e application of the method for reasonably sophisticated products or p rocesses would be too complicated. (C) 1997 Elsevier Science B.V.