Guidelines for consistent reporting of exchanges from/to nature within life cycle inventories (LCI)

Data availability and data quality are still critical factors for successfu l LCA work. The SETAC-Europe LCA Working Group 'Data Availability and Data Quality' has therefore focused on ongoing developments toward a common data exchange format, public databases and accepted quality measures to find sc ience-based solutions than can be widely accepted. A necessary prerequisite for the free flow and exchange of life cycle inventory (LCI) data and the comparability of LCIs is the consistent definition, nomenclature, and use o f inventory parameters. This is the main subject of the subgroup 'Recommend ed List of Exchanges' that presents its results and findings here: Rigid parameter lists for LCIs are not practical; especially, compulsory li sts of measurements for all inventories are counterproductive. Instead, pra ctitioners should be obliged to give the rationale for their scientific cho ice of selected and omitted parameters. The standardized (not: mandatory!) parameter list established by the subgroup can help to facilitate this. The standardized nomenclature of LCI parameters and the standardized list o f measurement bases (units) for these parameters need not be applied intern ally (e.g. in LCA software), but should be adhered to in external communica tions (data for publication and exchange). Deviations need to be clearly st ated. Sum parameters may or may not overlap - misinterpretations in either direct ion introduce a bias of unknown significance in the subsequent life cycle i mpact assessments (LCIA). The only person who can discriminate unambiguousl y is the practitioner who measures or calculates such values. Therefore, a clear statement of independence or overlap is necessary for every sum param eter reported. Sum parameters should be only used when the group of emissions as such is m easured. Individually measured emission parameters should not be hidden in group or sum parameters. Problematic substances (such as carcinogens, ozone depleting agents and the like) may never be obscured in group emissions (together with less harmful substances or with substances of different environmental impact), but must be determined and reported individually, as mentioned in paragraph 3.3 of this article. Mass and energy balances should be carried out on a unit process level. Mas s balances should be done on the level of the entire mass flow in a process as well as on the level of individual chemical elements. Whenever possible, practitioners should try to fill data gaps with their kn owledge of analogous processes, environmental expert judgements, mass balan ce calculations, worst case assumptions or similar estimation procedures.