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Characterisation Method Information
Characterisation Method Name:
SO2 impact on NEX
Date Completed:
Principal Method Name:
EPS: acidification and secondary aerosol pathways
Method Description:
NEX is Normalised EXtinction of species.

Model 1, acidification pathway

The characterisation factor is determined by the empirical method.

Category indicator value in system considered

In Sweden approximately 2 % of the threatened evertebrates are claimed to be threatened by acidification. (Faunavårdskommitten 1988). If this is assumed to be relevant for other acidified regions, roughly estimated to 10% of the earth’s land area, this would indicate that as a global average 0.2 % of the NEX are endangered due to SO2.

Contribution to category indicators value from a flow unit

The global emission of SOx is 170 million tons per year resulting in an average contribution of 5.88E-12 per kg SO2.

Calculation of pathway specific characterisation factor

0.002*5.88E-12 = 1.18E-14 NEX per kg SO2.

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 "SO2 impact on severe morbidity", i.e. 2.83 kg ‘effective’ PM10/kg SO2.

Calculation of pathway specific characterisation factor

According to "PM10 impact on NEX", there are -1.08E-13 NEX per kg PM10. This will give -2.83*1.08E-13 = -3.06E-13 NEX per kg SO2.
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.

Existing Characterisation Factors of SO2 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 = *
SO2 -2.94E-13 NEX/kg 2 pathways