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directly on value of statistical life (VSL). Additionally, due to the existence of
internationally accepted damage indicators by the World Health Organization
(WHO) in the form of disability adjusted life years (DALY) (Murray and Lopez,
1996; Hofstetter, 1998) and YOLL (Meyerhofer et al., 1998), other types of weight-
ing across the different damage endpoints are available.
Thus, in the case of damages that cause morbidity, the decision-maker must
select among the assessment by DALY or physical impact parameters, for
instance, emergency room visits, asthma attacks, restrictive activity days, etc. For
cancer, a selection must be made among DALY, YOLL and the physical impact
parameter cases of cancer. In the case of morbidity, the choice is among DALY,
YOLL and the physical impact parameter cases of death. Finally, in the case of
site-specific assessment, individual risk can be evaluated. These different weight-
ing options are summarized for the decision-maker in the first table which forms
part of Figure 6.9, named weighting of impacts, in which all together four decision
tables relevant for weighting and aggregation are presented. Two other tables
concern the discount rate for monetization and the cultural theory for DALY, and
the last one concerns decisions related to the aggregation of damages. In this
figure, default selections are presented as an illustration of a typical case for
study of environmental damage estimations in industrial process chains.
In the table for the weighting of impacts, one entry must be made for each
damage class. These damage classes are the manmade environment, natural envi-
ronment and human health AoPs, as well as all the so-called global indicators such
as GWP and ODP that could be related to the life support functions and resources
sub-AoPs if resource depletion is considered an environmental problem (see Figure
6.9).
Human health is divided into morbidity, cancer and mortality. In principle, the
monetization can be done for all the damage classes, either by damages or abatement
costs. DALY can only be used for the damages to human health. Although no more
than the preferred option must be selected for monetization and DALY, in the case
of using physical impact parameters the selected parameters should be mentioned
here. For the monetization a discount rate must be defined. Although in principle
any rate can be chosen, here 0, 3 and 10% are proposed according to the standard
values used in the ExternE project (EC 1995). In the case of using DALY, one
cultural perspective must be selected. According to Hofstetter (1998), three arche-
types represent human socioeconomic perceptions quite well: hierarchist, egalitarian
and individualist.
Finally, it must be decided in which way the damage classes are aggregated. Of
course this is only possible if the classes have the same weighting unit, e.g., monetary
values or DALYs. In principle, two options for aggregation exist. One option is to
aggregate directly in the damage matrix, called intermediate aggregation, which is
less laborious due to fewer matrix operations. The other option is to undertake a
final aggregation reducing the number of components in the damage profile, which
makes the steps more transparent but risks confusion. In any case, the final result
will be the same. Also, according to certain criteria, groups (for instance, AoPs),
can be created to show unity.
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