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Characterisation Method Information
Characterisation Method Name:
CO impact on Severe morbidity
Date Completed:
Principal Method Name:
EPS: direct exposure pathway and global warming pathway
Method Description:
Model 1, direct exposure pathway

The characterisation factor is determined by an empirical method.

1.2 billion people live in urban OECD areas and 1.4 billion in urban areas in non-OECD
countries. WHO criteria for CO is estimated to be exceeded in almost 50% of the cities
(see results from GEMS/ UNEP/WHO report "assessment of urban air quality" 1988). It is likely that only a part of the population in these cities is exposed. This part is assumed to consist of those who work or live permanently in the centre of the cities, roughly less than a third of the population, i.e. 4.310 8 . 0.1% of the population which experiences concentrations above the WHO recommendations is assumed to be effected. This figure is chosen because the sensitive group is people suffering from cardiovascular diseases. As CV(Cardio-Vascular) diseases account for almost a third of the deaths as a global average (check, ref.) one can assume that the last percent of their lifetime is effected. Critical levels are estimated to be exceeded during 1% of the time. (99%-ile or 10 cases per year of exceedence of the 8-hour mean) This would mean 4.310 8 *0.001*0.01 = 4300 person-years per year of severe morbidity.

Global emissions of CO are 2600 million tons. Man made emissions account for 1600
million tons (UNEP/GEMS Env. Library No 4, 1991) and dominate the urban exposure pattern. The contribution from 1 kg CO is at an average 1/(160010 9 ) = 6.2510 -13 .

The characterisation factor of CO for severe morbidity is thus equal to 4300*6.2510 -13 =
2.6910 -9 person-years/kg for the direct exposure pathway.

Model 2, global warming pathway

The characterisation factor is determined by an equivalency method using CO2 as a

Equivalency factor

GWP100 for CO is 3. (Houghton et. al, 1990)

The characterisation factor of CO2 for severe morbidity was determined to 3.53E-07 person-years/kg CO2. We thus obtain 3*3.53E-7 = 1.06E-6 person-years/kg CO for the global warming pathway.

The characterisation factor for both pathways is thus 2.69E-9 + 1.06E-6 = 1.06E-6
person-years/kg CO.

Literature Reference:
Houghton, J.T Jenkins, G.J. and Ephraums, J.J., (Ed.) (1990) Climate change The IPCC scientific assessment. Cambridge University Press
Methodological Range:
CO as a molecule has a residence time in air of approximately half a year. However rural background levels are in the order of 0.05 0.25 mg/m 3 which is several times below the WHO guidelines designed to protect from health effects (10 mg/m 3 ). This means that the direct impacts on health due to CO are mainly local, close to the sources. As the emissions and local exposure patterns considered is repeated on a global urban level (traffic) the system chosen is urban and global and during the year 1990.

Existing Characterisation Factors of CO impact on Severe morbidity
Characterisation Parameter Category Indicator Impact Indication Principle Aspect Substance Quantity Unit Notes
CFactor Severe morbidity EPS/2000
Type = Emission
Direction = Output
Media = Air
Geography = *
CO 1.06E-06 p yr/kg 2 pathways