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 1.18E14 per kg SO2. The characterisation factor of NH3 for NEX will thus be 0.94 * 1.18E14 = 1.11E14 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 1.08E13 per kg PM10. The characterisation factor of NH3 for NEX will thus be –2.00 * 1.08E13 = 2.16E13 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 1.83E13 NEX per kg NOx. The characterisation factor of NH3 for NEX will thus be 2.71 * 1.83E13 = 4.96E13 NEX per kg NH3. Calculation of characterisation factor The added characterisation factor for NEX is thus 1.11E14 + (2.16E13 ) + 4.96E13 = 2.78E13 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: 
Characterisation Parameter  Category Indicator  Impact Indication Principle  Aspect  Substance  Quantity  Unit  Notes  
CFactor  NEX  EPS/2000 

NH3  2.78E13  NEX/kg  3 pathways 