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Characterisation Method Information
Characterisation Method Name:
NH3 impact on NEX
Version:
1999
Date Completed:
1999
Principal Method Name:
EPS: acidification, eutrofication and secondary aerosol pathways
Method Description:
NEX is Normalised EXtinction of species.

Model 1, acidification pathway

The characterisation factor is determined by an equivalency method using SO2 as a reference.

Equivalency factor

The equivalency factor was determined in "NH3 impact on fish&meat" to 0.94.

Calculation of pathway specific characterisation factor

The characterisation factor of SO2 for NEX is 1.18E-14 per kg SO2. The characterisation
factor of NH3 for NEX will thus be 0.94 * 1.18E-14 = 1.11E-14 per kg NH3.

Model 2, secondary aerosol pathway

The characterisation factor is determined by an equivalency method using PM10 as a reference.

Equivalency factor

The same equivalency factor is used as in "NH3 impact on severe morbidity", i.e. 2.00 kg ‘effective’ PM10/kg NH3.

Calculation of pathway specific characterisation factor

The characterisation factor of PM10 for NEX is -1.08E-13 per kg PM10. The characterisation factor of NH3 for NEX will thus be –2.00 * 1.08E-13 = -2.16E-13 per
kg NH3.

Model 3, eutrofication pathway

The characterisation factor is determined by an equivalency method using NOx as a reference.

Equivalency factor

The equivalency factor is based on the N content, i.e. each kg of NH3 equals 46/17 = 2.71kg NOx in terms of eutrofication capacity.

Calculation of pathway specific characterisation factor

The eutrofication pathway specific characterisation factor of NOx is 1.83E-13 NEX per kg NOx. The characterisation factor of NH3 for NEX will thus be 2.71 * 1.83E-13 =
4.96E-13 NEX per kg NH3.

Calculation of characterisation factor

The added characterisation factor for NEX is thus 1.11E-14 + (-2.16E-13 ) + 4.96E-13 = 2.78E-13 per kg NH3.
Literature Reference:
Steen B (1999b): A systematic approach to environmental priority strategies in product development (EPS). Version 2000 – Models and data of the default method CPM report Chalmers University of Technology Sweden
Methodological Range:
The system is global and the time period is 1990. The spatial system borders are wide enough to contain all of the modelled impact quantity (NEX on a global or local level). The response time for the modelled quantity is normally in the order of several years to decades, depending on the reproduction cycles of the NEX and on the volumes and alkalinity of the inland waters at risk for acidification. This means that present observed impacts are mainly caused by emissions several years ago. Despite this the characterisation factor of NH3 for NEX will be modelled as if everything happened within 1990. The magnitude of the error, which may be introduced through this, is discussed and estimated later.
Notes:

Existing Characterisation Factors of NH3 impact on NEX
Characterisation Parameter Category Indicator Impact Indication Principle Aspect Substance Quantity Unit Notes
CFactor NEX EPS/2000
Type = Emission
Direction = Output
Media = Air
Geography = *
NH3 2.78E-13 NEX/kg 3 pathways