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Characterisation Method Information
Characterisation Method Name:
Ethylene impact on crop
Date Completed:
Principal Method Name:
EPS: oxidant pathway; global warming pathway
Method Description:
Model 1, oxidant pathway
The characterisation factor is determined by an empirical method.

Category indicator value in system considered
Hasund, Hedvåg and Pleijel (1990) estimated the loss in crop production during 1986-
1988 due to anthropogenic emissions to 300000 tons in Sweden. The mean reduction in
harvest gain was 6-21% with a best estimate of 9%. The estimates in USA range from 10
-100 billion dollars, IVL(Swedish Environmental Research Institute)-report B1080. The world production of crops, potatoes and sugar beats was about 2400 million tonnes 1990 according to FAO(Food and Agriculture Organization of the United Nations) yearbook. A 9 %
reduction means decreased harvests by 216 million tonnes.

Contribution to category indicators value from a flow unit

The anthropogenic emission of NMHC is 40 tg/year according to Stern (1986). VOC is
assumed to be of about the same magnitude. The natural emission is much greater, but
consists to a large part of therpenes, which are no strong oxidant precursors. The
influence on oxidant formation in Atlanta, USA from natural VOC was determined by the
C14-method by Lewis et al. (1999). It was shown to have a minor influence.
It is not clear which part of tropospheric ozone on a global scale that is rate controlled by NOx and which part that is controlled by VOC, methane and CO. It seems however as if NOx is the dominating rate controller in the northern countries, while VOC is most important in central Europe and similar regions. Half of the oxidant formation is assumed to be rate controlled by VOC. In terms of ozone creation potential ethylene is somewhat more potent than other hydrocarbons, about 1.8 times. The contribution is therefore 1.8*0,5/4.0·E+10 = 2.25·E-11 per kg ethylene.

Calculation of pathway specific characterisation factor

The characterisation factor of ethylene for crop loss is therefore 2.16·10 11 *2.25·E-11 =4.86 kg crop/kg ethylene.

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 (Intergovernmental Panel on Climate Change) 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 Later this statement was withdrawn by IPCC, with the motivation that the uncertainty was too large.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 crop loss is 7.56E–04 kg crop/kg CO2. Thus the
characterisation factor of ethylene for crop loss is 11*7.56E–04 = 8.32E–03 kg crop/kg

Calculation of characterisation factor
The total characterisation factor for both pathways is thus 4.86 + 8.32E–03 = 4.87 kg crop/kg ethylene.

Literature Reference:
1. Hasund, Hedvåg and Pleijel, Swedish Env Protection Agency report 3862, 1990 2. Stern, A.C., “Air Pollution” Vol VI, Academic Press, 1986 3. Lewis, C., Stevens, R., Rasmussen, R., Cardelino, C. and Pierce, T. , “Biogenic Fraction of Ambient VOC: Comparison of Radiocarbon, Chromatographic, and Emissions Inventory Estimates for Atlanta, Georgia”, J. Air & Waste Manage. Assoc., Vol 49, pp.299-307, (1999) 4. Houghton, J.T Jenkins, G.J. and Ephraums, J.J., (Ed.) (1990) Climate change – The IPCC scientific assessment. Cambridge University Press
Methodological Range:
The ozone level in rural areas has increased significantly since pre-industrial time. The reaction velocity for ethylene to form oxidants is normally in the order of days, but during the dark periods in the arctic regions the residence time of ethylene can be much longer. However a time system border of one year is believed to be sufficient for impact modelling. The system borders used for the oxidant model are thus global and the year 1990. For the global warming pathway the same system borders as for CO2 apply, i.e. 100 years.

Existing Characterisation Factors of Ethylene impact on crop
Characterisation Parameter Category Indicator Impact Indication Principle Aspect Substance Quantity Unit Notes
CFactor Crop EPS/2000
Type = Emission
Direction = Output
Media = Air
Geography = *
Ethylene 4.87 kg/kg 2 pathways