Page 124 - Materials Chemistry, Second Edition

L1644_C03.fm Page 99 Tuesday, October 21, 2003 3:11 PM

Most of the valuation studies are based on a context in which the individuals
involved are exposed to an accidental risk leading to a loss of life expectancy of
about 30 to 40 years; thus, the transfer of results to the air pollution context is
problematic. Increased mortality from air pollution is mainly expected to affect
old people in poor health, leading to a loss of life expectancy between some few
days (harvesting effect due to a high pollution episode — acute mortality) and
some few years (resulting from long-term exposure to increased levels of air
pollution — chronic mortality). An alternative valuation approach that seems to
better reflect the context of mortality related to air pollution is to value a change
in risk in terms of the willingness to pay for life years and to derive a value of a
life year lost (VLYL). Because little empirical evidence on the WTP for LYLs
exists, the ExternE study has developed a theoretical framework to calculate the
VLYL from the VSL. Assuming for simplicity that the value of a life year is
independent of age, a relationship between the VSL and the VLYL is established
(Krewitt et al., 1999).
Rabl et al. (1998) indicate that based on this assumption, a VLYL corresponds
to approximately 0.1 million U.S.$. In principle, a discount rate of 3% is applied
throughout the case study of this book. Based on the uncertainty analysis in
Chapter 5, this book will try to compare the uncertainties due to this valuation step
with other sources of uncertainties in environmental impact analysis.

3.7.5 ECO-INDICATOR 99 AS APPROACH USING CULTURAL THEORY
AND DALY
Eco-indicator 95 was based on the distance-to-target approach; however, this method
has been criticized because it offers no clear-cut objective way to define sustainable
target levels. Thus, the subjectivity of the weighting factors used contributed to the
development of a new damage-oriented approach: Eco-Indicator 99 (Goedkoop and
Spriensma, 1999).
To calculate the eco-indicator score, three steps are necessary:

1. Inventory of all relevant emissions, resources extraction and land-use in
all processes that form the life-cycle of a product, which is the standard
procedure in life-cycle assessment as described in Chapter 2
2. Calculation of the damages these flows cause to human health, ecosystem
quality and resources
3. Weighting of these three damage categories

To simplify the weighting procedure, damage categories were identified, and as
a result new damage models were developed that link inventory results into three
damage categories: damage to 1) human health, 2) ecosystem quality, and 3)
resources. A brief description of these three damages follows. Figure 3.10 gives an
overview of the eco-indicator 99 method.

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