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Characterisation Method Information
Characterisation Method Name:
Butadiene impact on YOLL
Version:
1999
Date Completed:
1999
Principal Method Name:
EPS: cancer pathway, global warming and oxidant pathways
Method Description:
YOLL stands for Year of Lost Life.


Model 1, cancer pathway

The characterisation factor is determined by the empirical method.

Category indicator value in system considered

The entire population on earth is exposed to butadiene. Only a few measurements of butadiene have been made. Shah and Sing (1988) reports mean values for benzene and butadiene that indicates a ratio of 5. This would mean that a best estimate of the global
average butadiene concentration would be 2 mg/m 3 . This is also the value obtained from the USEPA AIRS database for 1990 as an average from 49 stations.
IARC has classified butadiene as a human carcinogen. Butadiene gives a net lifetime risk of 1·E-05 for 0.02–0.1 ppb butadiene (Victorin, 1998). This corresponds to about 6.67E-05 per mg/m 3 as a best estimate.
Mortality for all sorts of cancer in the European union was 62 % 1990. (Berrino et.al. 1999). The global average is 64%. (Parkin et. al., 1990) The average reduction of life expectancy was estimated in "Benzene impact on YOLL" to 24 years. The global average life expectancy is 65 years. This means that there are 5.28E+09 *0.64*6.67E-05 *2*24/65 = 1.64E+05 YOLL during 1990.

Contribution to category indicators value from a flow unit

The main sources of butadiene are from combustion engines and from burning of wood.
USEPA estimates the US national emissions to 109 000 metric tons. The main sources were mobile on- and off-road sources (about 82%) and bio-mass burning (16%) (USEPA, 1996). The same year the emissions of CO in the US were estimated to 85 million tonnes,
mainly from mobile sources. This gives a ratio of 1.28E-03 for the US emissions of butadiene and CO.
The global anthropogenic CO emission was estimated to 1600 million tonnes. Assuming the same butadiene/CO ratio as in the US, the global anthropogenic butadiene emission from traffic may be estimated to 0.00128*1600 = 2.05 million tonnes.
Emissions from burning of bio-mass may increase this figure on a global level but at
present it is assumed to be of less importance than the emissions from traffic. This means that the average contribution is 1/(2.05E+09 ) = 4.88E-10 per kg butadiene.

Calculation of pathway specific characterisation factor

The characterisation factor will thus be 1.64E+05 * 4.88E-10 = 8.00E-05 YOLL/kg butadiene.

Model 2, global warming pathway

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

Equivalency factor

The GWP100 was estimated by IPCC to 11 in one of the early reports. (1990). Later this
statement was withdrawn by IPCC, with the motivation that the uncertainty was too
large. In the EPS context however, omitting it would create a larger error than including
it, so the equivalency factor 11 will still be used.

Calculation of pathway specific characterisation factor

The characterisation factor of CO2 for YOLL was determined to 7.93E–07 YOLL/kg CO2 . The characterisation factor of butadiene for YOLL will therefore be 11*7.93E–07 = 8.72E–06 YOLL/kg butadiene.

Model 3, oxidant formation pathway

The characterisation factor is determined by an equivalency method using ethylene as a
reference.

Equivalency factor

The POCP for butadiene is not listed in Lindfors et.al.(1994), but extrapolating from n-butane, with a peak POCP of 0.554 and 1-butene with 0.799 it is likely that 1,3-butadiene has a POCP around 1.

Calculation of patway specific characterisation factor

The oxidant pathway specific characterisation factor of ethylene for YOLL is 1.20E-05 YOLL/kg ethylene. This means that the oxidant pathway specific characterisation factor
will be 1*1.20E-05 = 1.20E-05 YOLL/kg butadiene.

Calculation of characterisation factor

The resulting characterisation factor from adding the three pathways is 8.00E-05 +
8.72E–06 + 1.20E-05 = 1.01E-04 YOLL/kg butadiene.
Literature Reference:
1. Shah, J. and Sing, H., “Distribution of volatile organic chemicals in outdoor and indoor air. A national database”. Environ. Sci. Technol., Vol 22, No. 12, 1988. 2. Parkin, D.M., Pisani, P. and Ferlay, J., “Estimates of the worldwide mortality from 25 major cancers in 1990”. International Journal of Cancer. (In Press) 3. USEPA, Office of Air Quality Planning and Standards, National Air Quality and Emissions Trends Report, 1996. 4.Lindfors, L.G.,Christiansen, K., Hoffman, L., Virtanen, Y., Juntilla, V. Leskinen, A., Hanssen, O-J., Rønning, A., Ekvall, T. and Finnveden, G., LCA-Nordic, Technical report No 10, Tema Nord 1995:503, Nordic Council of Ministers, Copenhagen 1994.
Methodological Range:
Including emissions from anywhere at the globe 1990 and considering a residence time of several days for butadiene and its reaction products, the environmental system will also be global. As butadiene causes cancer, there is a reason for using a 20-year system border, but as we use a linear dose-response model, we restrict the system borders to the year 1990. In terms of qualitative system borders, we look at human health issues ecosystem production capacity. No effects on bio-diversity, resources or aesthetics are included. For the global warming pathways, the same system borders as for CO2 is relevant, i.e. 100 years.
Notes:

Existing Characterisation Factors of Butadiene 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 = *
Butadiene 1.01E-04 p yr/kg