Environmental Engineering Reference
In-Depth Information
Figure 2.8
An example of a polygon plot summarizing LCA results on
three products, based on 15 attributes.
Source: Courtesy of the US Department of Energy, Building Technologies Office.
ApotentialproblemofLCAisinthevaluejudgmentsinvolvedinthelasttwo
steps above, where weighting functions might be used to sum up the total
impact from different categories (Graedel and Allenby, 2010). There is no
sound basis to select these weights, but results of the analysis often depend
on the choice of weights (Carlsson Reich, 2005). Also, there is no standard
methodology to aggregate inventory data into cumulative indicators (step
2). Different impacts, such as acidification of oceans or human
carcinogenicity or smog formation, have very different consequences on the
ecosystem. LCA study on polystyrene (PS) and recycled-paper egg packages
found the PS to contribute more to acidification potential and winter and
summer smog, while paper packages contributed more to heavy metal and
carcinogenicity impacts (Zabaniotou and Kassidi, 2003). In such situations,
it is the weighting factors of attributes that determine the overall
environmental merit of the products (Goedkoop and Spriensma, 2001;
