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Characterisation Method Information
Characterisation Method Name:
SO2 impact on NEX
Version:
1999
Date Completed:
1999
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.
Notes:

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