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Impact Indication Principle
In daily life the confusion over what people consider to be an environmental problem is big. The term environment is by nature so general that almost everything can be included. Before we can make
any sense we have to define what we mean by environment, or what the "Eco" is we want to indicate.

We have found a wide range of different
concepts describing the role of the environment in society. On the most
basic level the environment is regarded as a basis for our existence and
damage to the environment is considered a direct threat to mankind. This
kind of thinking is often referred to as the sustainability concept.

The basic idea is that, if we damage our environment too much it will
no longer be able to support mankind. Basically the sustainability is
aimed at avoiding disastrous developments that would endanger
humanity. On a much different level a healthy environment is seen as one of the
elements influencing the broad concept of well being, welfare or even
human happiness. In this concept threats to the environment are not to be
seen as problems that can totally disrupt society. On this level, also
subtle changes in the environment are taken into account. A small
increase in a certain disease or a small decrease in biodiversity in a
certain area, are seen as damages, although such threats are not really a
threat to mankind as a whole. We propose to take the latter approach.
That is, we base ourselves on very small changes in the environment, and
not so much on the possibility of disasters. Apart from environmental considerations, landscapes in which the ecosystems are functioning
have also other values, like the cultural heritage embodied in changes in
the landscape made by earlier civilisations and populations. In fact
earlier damages to ecosystems (old aqueducts, castles, canals, dams
etc.) have a positive cultural value. It is not our intention to express
these cultural values in the Eco-indicator.

We have chosen the following
definition of the term environment:

A set of biological, physical and
chemical parameters influenced by man, that are conditions to the
functioning of man and nature. These conditions include Human Health,
Ecosystem Quality and sufficient supply of Resources.

In the Eco-indicator 99 we only look at environmental problems as they occur in Europe.

From this definition it follows that there are basically three damage
• Human Health
• Ecosystem Quality
• Resources
• “Human Health” contains the idea that all human beings, in present and future,
should be free from environmentally transmitted illnesses, disabilities
or premature deaths

• “Ecosystem Quality” contains the idea that non-human species should not suffer from disruptive changes of their
populations and geographical distribution,

• “Resources” contains the idea
that the nature’s supply of non-living goods, which are essential to the
human society, should be available also for future generations.
Please note that it is also possible to select other damage categories,
such as material welfare, happiness, equality, safety etc… We have chosen
not to include these aspects, partially because it is too complex to
define or model such damage categories and partially because in general
products can have both an intended positive effect as well as a
negative (environmental) effect. This would for instance lead to the strange
conclusion that pesticides have a strong positive effect on the human
welfare, while at the same time Human Health could be threatened.

In order to calculate the damage categories we will use a number of
intermediate results. We will define and describe these intermediate results and
we will make it possible to explicitly calculate and publish such results. This will enhance the transparency of the method and make it easier to compare the results in this methodology with other impact assessment methods.
This system chose hierarchical version as the default. In this version, we choose to include facts that are backed up by scientific and political bodies with sufficient recognition. The hierarchical attitude is rather common in the scientific
community, and among policy makers. A typical example is the wide acceptance of the IPCC guidelines for climate change.

geological scale: Europe

Mark Goedkoop and Renilde Spriensma 17 April 2000 The Eco-indicator 99 A damage oriented method for Life Cycle Impact Assessment Methodology Report Second edition

Category Indicators
DALY (Disability Adjusted Life Years)

The health of any human individual, being a member of the present or a future generation, may be damaged either by reducing its duration of life by a premature death, or by causing a temporary or permanent reduction of body functions (disabilities). According to current knowledge, the environmental sources for such damages are mainly the following:
• Infectious diseases, cardiovascular and respiratory diseases, as well as forced displacement due to the climate change.
• Cancer as a result of ionising radiation.

• Cancer and eye damages due to ozone layer depletion.
• Respiratory diseases and cancer due to toxic chemicals in air, drinking water and food.
These damages represent the most important damages to Human Health caused by emissions from product systems. The damage category is not complete. For instance, damage from emissions of Cd and
Pb, endocrine disrupters etc. cannot yet be modelled. Furthermore health damages from allergic reactions, noise and odour cannot yet be modelled.
To aggregate different types of damages to Human Health (which is highly desirable in view of the
large number of different types of sickness), a tool for comparative weighting of disabilities is needed.
We have chosen to use the DALY (Disability Adjusted Life Years) scale, which has been developed by
[MURRAY ET AL 1996] for the WHO and World Bank. The original purpose of the DALY concept was
to have a tool to analyse the rationale of national health budgets.
The core of the DALY system is a disability weighting scale. This scale has been developed in a
number of panel sessions. The scale lists many different disabilities on a scale between 0 and 1 (0 meaning being perfectly healthy and 1 meaning death).

With this system, we can calculate the number of Disability Adjusted Life Years if we know how many people in Europe are exposed to a certain background concentration of toxic substances in air, drinking
water and food. [HOFSTETTER 1998], who has studied the use of DALYs in LCA, supplied most data for respiratory and carcinogenic effects due to chemical releases. Hofstetter also performed the calculations for climate
Next to this data, we use the proposal of Frischknecht, Braunschweig, Hofstetter and Suter
[FRISCHKNECHT ET AL 1999], to include the effect of ionising radiation. The unit for the damage category Human Health is DALY. This can easily be explained. A flow of toxic substances in tons per year will result in a number of DALY per year. If we leave out the "per
year" we find a mass loading is equivalent to a number of DALYs.
Default Unit:

[Murray et al 1996] Murray, Christopher; Lopez, Alan; The Global Burden of Disease, WHO, World Bank and Harvard School of Public Health. Boston, 1996.

[Hofstetter 1998] Hofstetter, P. (1998): Perspectives in Life Cycle Impact Assessment; A
Structured Approach to Combine Models of the Technosphere, Ecosphere and Valuesphere. , Kluwers Academic Publishers, 1998, Info:

[Frischknecht et al 1999] Frischknecht R., Braunschweig A., Hofstetter P., Suter P. (1999),
Modelling human health effects of radioactive releases in Life Cycle Impact Assessment, Draft from 20 February 1999, to be submitted

Potentially Disappeared Fraction (PDF)

Ecosystems are very complex, and it is very difficult to determine all damages inflicted upon them. An important difference with Human Health is that even if we could, we are not really concerned with the individual organism, plant or animal. The species diversity is used as an indicator for Ecosystem Quality. We express the ecosystem damage as a percentage of species that are threatened or that disappear from a given area during a certain time.


For ecotoxicity, we use a method recently developed by RIVM for the Dutch Environmental Outlook
[MEENT AND KLEPPER1997]. This method determines the Potentially Affected Fraction (PAF) of
species in relation to the concentration of toxic substances. The PAFs are determined on the basis of
toxicity data for terrestrial and aquatic organisms like micro-organisms, plants, worms, algae,
amphibians, molluscs, crustaceans and fish . The PAF expresses the percentage of species that is
exposed to a concentration above the No Observed Effect Concentration (NOEC). The higher the concentration, the larger the number of species that is affected.

When an emission (mass) is released, the concentration in an area will be increased temporarily. This change in concentration will cause a change in the PAF value. The damage caused by the emission of this substance depends on the
slope of the curve in a suitably chosen working point. In [MEENT ET AL 1999] it is postulated that the marginal damage to Ecosystem Quality from a specific emission depends on the present level of damage caused by the present mixture of substances in the
environment. This means that we cannot use the background concentrations of single substances.
Instead we have to use the combined toxic stress resulting from the present mixture of substances in the environment, the so-called combi-PAF, to find the right working point and slope.

Being based on NOEC, a PAF does not necessarily produce observable damage. Therefore, even a high PAF value of 50% or even 90% does not have to result in a really observable effect. PAF should be interpreted as toxic stress and not as a measure to model disappearance or extinction of species.
Acidification and eutrophication
For acidification and eutrophication, we cannot use the PAF concept directly, since damage from acidification and eutrophication is caused by an entirely different and complex biochemical mechanism.
Instead, we will have to look at observed effects from acidification and eutrophication on plants. From these observations the probability that a plant species still occurs in an area can be determined. This is
called the Probability Of Occurrence or POO [WIERTZ ET AL 1992], which is translated for this project into Potentially Disappeared Fraction (PDF): PDF=1-POO. The computer model “Natuur Planner” developed by RIVM is used for both the fate modelling and the damage modelling for NOx, SOx and NH3 depositions. A particular problem is the fact that acidification and eutrophication do not necessarily reduce the number of species. In fact very often the number of
plant species are increased. The solution used by the RIVM is the use of target species. These are the species that should occur on a specific type of ecosystem if there would have been no man-made
changes in the nutrient level or the acidity [BAL ET AL 1995]. The “Natuurplanner” contains a very detailed grid with an exact description of the type of ecosystem and the associated set of target species .
The same grid is also used for a site specific fate analysis.
The damage model calculates to what extent the number of target species increases or decreases if an additional deposition is added to the background. Interestingly, it is not possible to determine whether a damage is caused by changes in the nutrient level or the acidity. For this reason the impact categories have been combined.
Although the “Natuurplanner” is a very sophisticated instrument it is still only available for the
Netherlands. The crude assumption was made that the Dutch situation is representative for Europe.
Another problem of this impact category is that only damages to natural systems can be modelled and only if these damages occur through airborne depositions. So far we have been unable to include the effect of phosphate and other eutrophying emissions to water.

Land use

For land use, we also use the Potentially Disappeared Fraction (PDF) as indicator. In this case however, we do not consider target species but all species. The damage model is rather complex, as we need four
different models:
1. The local effect of land occupation
2. The local effect of land conversion
3. The regional effect of land occupation
4. The regional effect of land conversion
The local effect refers to the change in species numbers occurring on the occupied or converted land itself, while the regional effect refers to the changes on the natural areas outside the occupied or
converted area. The regional effect was first described by [MÜLLER-WENK 1998-2]. The data for the species numbers 1per type of land-use and some of the concepts used for the local effect are based on [KÖLLNER 1999].
The data on the species numbers are based on observations, and not on models. The problem with this type of data is that it is not possible to separate the influence of the type of land-use from the influence of emissions. For this reason some special care must be taken to avoid double counting of effects which
are included in land-use and which could be included also in other damage models.
The Ecosystem Quality damage category is the most problematic of the three, as it is not completely homogeneous. A temporary solution is proposed to combine PAF and PDF The unit for the damages to Ecosystem Quality is the PDF times area times year [m 2 .yr]. For land-use this unit is easy to explain: the damage increases with an increase in area size, an increase in occupation time or an increase in restoration time for a formerly converted area.. For ecotoxicity and for acidification/eutrophication some additional explanation is needed.

4 logical steps are needed:

1. Let us consider a steady state flow of x kg per year per m 2 . This flow will result in a steady state concentration y on a m 2 .
2. Now in LCA, we do not know the flow, but only the mass. A mass can be interpreted as a flow
during a certain time t.
3. This means, a mass can only be responsible for concentration y on a m 2 , during that certain time.
4. As the damage can be linked to the concentration, the flow can only be linked to a certain damage
in a certain area, during a certain time.
Default Unit:
[Müller-Wenk 1998-2] Müller-Wenk R. (1998-2): Land-use - The Main Threat to Species. IWOE
Discussion Paper no. 64, IWOE University of St.Gallen.

[Köllner 1999] Köllner, T.; Life-Cycle Impact Assessment for Land Use. Effect Assessment
Taking the Attribute Biodiversity into Account., submitted for the Journal of
Cleaner Production. April 1999.

Resource damage
In the Eco-indicator 99 methodology we only model mineral resources and fossil fuels. The use of agricultural and silvicultural biotic resources and the mining of resources such as sand or gravel, are considered to be adequately covered by the effects on land use. Biotic resources which are extracted
directly from nature, like fish and game or wild plants, are not modelled in Eco-indicator 99 so far.
In the case of non-renewable resources (minerals and fossil fuels), it is obvious that there is a limit on the human use of these resources, but it is rather arbitrary to give figures on the total quantity per resource existing in the accessible part of the earth crust. If we sum up only the known and easily
exploitable deposits, the quantities are quite small in comparison to current yearly extractions. If we include occurrences of very low concentrations or with very difficult access, the resource figures become huge. It is difficult to fix convincing boundaries for including or not-including occurrences between the two extremes, as quantity and quality are directly linked.

Because of this problem, the Eco-indicator 99 methodology does not consider the quantity of resources
as such, but rather the qualitative structure of resources. We have chosen to take the concentration of a resource as the main element of resource quality.
Market forces assure that the deposits with the highest concentrations of a given resource are depleted first, leaving future generations to deal with lower concentrations. Thus in theory, the average ore grade available for future generations will be reduced with the extraction of every kilo. This decreasing concentration is the basis for the resource analysis.
The resource analysis is very comparable to the fate analysis, instead of modelling the increase of the concentration of pollutants, we model the decrease of the concentration of mineral resources. [CHAPMAN and ROBERTS 1983] developed an assessment procedure for the seriousness of resource depletion, based on the energy needed to extract a mineral in relation to the concentration. As more
minerals are extracted, the energy requirements for future mining will increase. The damage is the energy needed to extract a kg of a mineral in the future
For fossil fuels we also use the concept of surplus energy. Much of the data is supplied by [MÜLLER-WENK 98-1] The unit of the Resources damage category is the “surplus energy” in MJ per kg extracted material, this is the expected increase of extraction energy per kg extracted material, when mankind has extracted an
amount that is N times the cumulative extracted materials since the beginning of extraction until 1990.
A value of 5 is chosen for N. As the surplus energy is dependent on the choice of N, the absolute value of the surplus energy has no real meaning. Surplus energy is used to add the damages from extracting different resources.

Default Unit:
[Chapman & Roberts 1983] Chapman, P.F.; Roberts, F. (1983): Metal Resources and Energy.
Butterworths Monographs in Materials

[Müller-Wenk 1998-1] Müller-Wenk, R. (1998-1): Depletion of Abiotic Resources Weighted on the Base
of "Virtual" Impacts of Lower Grade Deposits in Future. IWÖ Diskussionsbeitrag
Nr. 57, Universität St. Gallen, March 1998, ISBN 3-906502-57-0.