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Dimensions of impact information Levels of sophistication
1. Information on the effect of a pollutant standard NOEC slope
2. Pollutant fate information none some full
3. Target information none some full

FIGURE 7.1 Dimensions of impact information and levels of sophistication in life-cycle
impact assessment. (From Wenzel, H. et al., Environmental Assessment of Products. Volume 1
– Methodology, Tools and Case Studies in Product Development, Chapman & Hall, London,
1997. With permission.)

may include no, some or comprehensive fate information. The same holds true for
the information on the target system.
Category indicators for toxicity, but also for other endpoint-oriented impacts, are
generally calculated by multiplying the emitted mass M of a certain pollutant p with
a fate and exposure factor F and an effect factor E, i.e., the slope of the dose–response
and exposure–response functions (Nigge, 2000). In the general case in which the
transfer of the pollutant across different environmental media or compartments (e.g.,
air, water, soil) needs to be considered, Expression 7.1 gives the category indicator
of incremental damage, DD nm / (damage such as cases of cancer, a for YOLLs and
p
DALYs or U.S.$ for external environmental costs), characterizing the effect in the
compartment m of the pollutant p emitted in the initial compartment n:

DD nm = E ◊ m F nm ◊ M n (7.1)
p p p p
where
M n is the mass of pollutant p (kg) emitted into the initial medium n (air, water
p
or soil).
F nm is the fate and exposure factor for the emission of substance p into the initial
p
medium n and transfer into medium m in the form of (m .yr/m ) or
3
2
3
(m yr/m ), depending on the compartments considered and taking into
3
.
account the propagation, degradation, deposition, transfer among
media and food chain or bioconcentration routes.
3
2
E m is the effect factor (damage/m (mg/m )yr)) representing the severity of the
p . .
impact due to the substance p in medium m (air, water, soil or food chain).
The ratio DD nm / M n is called the damage factor (damage/kg; Hofstetter 1998).
p p
The release and target compartments are linked by the different fate and exposure
routes. For example, an emission to the air compartment can have impacts in the
air (inhalation), soil (via deposition) and water (absorption) target compartments.
The pollutants can be transported farther to other target compartments by other
routes (soil–plant etc.). A large variety of possible routes is between the release and
target compartments.
Expression 7.1 does not explicitly consider the distribution and number of
receptors affected by the pollutants. Depending on the impact category, the receptor
may be, among others, human population, material surface, crop yield and sensitive

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