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Characterisation Method Information
Characterisation Method Name:
NH3 impact on YOLL
Date Completed:
Principal Method Name:
EPS: secondary aerosol pathway
Method Description:
YOLL stands for Year of Lost Life.

Model for secondary aerosol pathway

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

Equivalency factor

An equivalency factor with SO2 is determined through the formula:
(MNH4/MNH3) / (MSO4/MSO2) = 0.706, where
MNH4 and MNH3 are the molecular weights of NH4 + and NH3, respectively, and MSO4 and
MSO2 are the molecular weights of SO4 and SO2, respectively.

Calculation of pathway specific
characterisation factor

The secondary aerosol pathway specific characterisation factor of SO2 for YOLL is
3.74E-05 YOLL/kg SO2, which thus will result in a characterisation factor for NH3 of
0.706*3.74E-05 = 2.64E-05 YOLL/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.

Existing Characterisation Factors of NH3 impact on YOLL
Characterisation Parameter Category Indicator Impact Indication Principle Aspect Substance Quantity Unit Notes
CFactor YOLL EPS/2000
Type = Emission
Direction = Output
Media = Air
Geography = *
NH3 2.64E-05 p yr/kg secondary aerosol pathway