PARENT SESSION
2C Advances in life cycle impact assessment; water and other issues
9:00 AM to 7:00 PM, Wednesday, 09 May 2001

(W/MC267) Increasing the environmental relevance of life cycle impact assessment.

Hauschild, Michael¹, Potting, José², ^{1 2}

ABSTRACT- The recently terminated Danish LCA Methodology Development and Consensus Creation Project has had a strong focus on increasing the environmental relevance of the life cycle impact assessment phase. New characterisation models have been developed for all the non-global emission-related impact categories comprising a larger part of the relevant environmental mechanism by moving the impact category indicator more in the direction of the protection areas. For several impact categories, the new characterisation models also include exposure assessment and - where possible - exceeding of threshold values. Both the fate of an emitted substance and the sensitivity of the target systems that are exposed to it will often depend on local and regional conditions surrounding the source and these vary from location to location. The environmental relevance of the indicator results will therefore also depend on the extent to which spatial variation in these parameters is taken into account. In the life cycle of a product, emissions may take place in many different places and sometimes little or nothing is known about the location. In order to be feasible in LCA, a characterisation method that takes into account spatial variation must therefore also be applicable in situations where no spatial differentiation is possible due to lack of information. Furthermore there are applications of LCA where spatial differentiation is unwanted. Therefore, the new characterisation factors are provided in a site-generic form as well as a site-dependent form with individual factors for each of the European countries. Furthermore, the spatially determined uncertainty of the site-generic factors is quantified to allow the user to assess that part of the uncertainty which is caused by refraining from spatial differentiation. The new factors can replace the existing characterisation factors or they can be used to provide quantitative information on the spatially determined uncertainty for the sensitivity analysis. Both lines of application are recommended in the new Danish LCA guidelines. Examples are given of their use and the implication to the results.

Key words: Environmental relevance, life cycle impact assessment, environmental mechanism, spatial differentiation