Page 107 - Materials Chemistry, Second Edition

L1644_C03.fm Page 82 Tuesday, October 21, 2003 3:11 PM

Design of Industrial Products (EDIP) (Hauschild and Wenzel, 1998) will be consid-
3
ered in the case study (MSWI). The HTP of the EDIP method has the unit m and
expresses the volume to which the substance emitted must be diluted in order to
avoid toxic effects as a consequence of the emission in question in the relevant
compartment. The HTP of the CML method is dimensionless. The HTP for every
pollutant “p” (HTP ) is calculated using the human toxicity factor (HTF ) for every
p
p
pollutant and the mass of every pollutant (M ) and shown in the following expression:
p
HTP = HTF M⋅ (3.1)
p p p
3
The HTF is expressed in units of m /kg in the EDIP method (Hauschild and
p
Wenzel, 1998) and in –/kg for the CML method (Heijungs et al., 1992). The overall
HTP for the functional unit is then the sum of all HTP as seen in the next expression
p
(expression of overall HTP for the functional unit):

HTP = ∑ HTP p (3.2)

Table 3.4 shows the HTP for the pollutants considered in the case study (MSWI).
It should be mentioned that ozone, nitrate and sulfate are not considered in these
HTFs due to the unavailability of the mass of these substances in the life-cycle
inventory because they are not directly emitted but formed during dispersion into
the atmosphere. Particulate matter with apparent diameter lower than 10 µm (PM )
10
is also not included because no HTF is available.

TABLE 3.4
Human Toxicity Potential from the CML and EDIP Methods for
Different Substances

Pollutant CML (–/kg) EDIP (m /kg)
3
As 4700 9.5·10 9
Benzo(a)pyrene 17 5.0·10 10
Cd 580 1.1·10 11
Ni 0.014 6.7·10 7
0.78 2.0·10 6
NO x
1.2 1.3·10 6
SO 2
Sources: CML — Heijungs, R. et al., Environmental life-cycle assessment of products
— guide and backgrounds, technical report, CML, University of Leiden, The Nether-
lands, 1992; EDIP — Hauschild, M. and Wenzel, H., Environmental Assessment of
Products — Scientific Background, Vol. 2, Chapman & Hall, London, 1998.

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