|Characterisation Method Name:|
|NOx impact on Wood|
|Principal Method Name:|
|EPS: N-nutrification pathway and secondary particles pathway|
|Model 1, N-nutrification pathway|
The characterisation factor is determined by a mechanistic method.
Nitrogen is a rate limiting factor for wood growth in a large part of the world.
About 40% of the land area in the temperate regions are covered with forests, and about
50% of the emissions of NOx are assumed to deposit on land areas. Most of the global
emissions are estimated to origin in temperate regions. Thus, from an average global emission of 1 kg of NOx, 0.2 deposits on temperate forests and contribute to increased growth, where N deficiency is growth limiting. If half of the N is used by the trees in the wood structure (ratio experienced when fertilising with calcium ammonium nitrate), if 10% of the forests have nitrogen deposition above the critical load, and if the wood consists of 1% N, (on dry basis), then 1 kg NOx will result in 0.4*0.5*0.5*0.9*14/46*100 =2.74 kg wood.
As the net effect is an increase of wood growth, we obtain a negative characterisation
factor, -2.74 kg wood/kg NOx.
Model 2, secondary particles pathway
The characterisation factor is determined by an equivalency method using PM10 as a reference.
As for Severe morbidity of EPS for NOx, the equivalency factor is 1.0.
The characterisation factor for PM10 was estimated to 0.00991 kg wood per kg PM10
giving a characterisation factor for NOx of 0.00991 kg wood per kg NOx.
For both pathways we get -2.74 +0.00991 = -2.73 kg wood/kg NOx.
|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|
|The residence time in air in the order of a week and the residence time in soil is less than a year. The flow group is emissions anywhere on the globe during 1990. The environmental system investigated is therefore chosen to be global during 1990|
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