1 Introduction
2 Sources of uncertainties in the calculation of normalization factors
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F1: the selection for the sources of data amongst statistical database for NOx, SOx, NH3, CO, PM2.5/PM10 and water withdrawals (from F1.1 to F1.6);
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F2: the classification of environmental statistics as ILCD elementary flows for NOx, and SOx (F2.1 and F2.2);
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F3: the classification of PM2.5 and PM10;
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F4: the assumptions made on the typology and height of emission sources for NOx, SOx, NH3, CO and PM2.5/PM10 (F4.1, F4.2, F4.3, F4.4, F4.5);
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F5: the use of regionalized characterization factors (CFs) for water depletion only.
2.1 Sources of uncertainty in the inventory
2.1.1 Selection of the data sources (F1)
2.1.2 Classification of data as LCI elementary flows (F2)—NOx and SOx
2.2 Sources of uncertainty in the characterization
2.2.1 Classification of substances (F3)—PM2.5 and PM10
2.2.2 Specification of the emission compartments (F4)
2.2.3 Spatial differentiation of characterization factors (F5)
3 Uncertainty and sensitivity analysis
3.1 Step 1: Definition of the uncertainty factors and their probability distribution
3.2 Step 2: Generation of a sample set of combinations (input)
3.3 Step 3: Evaluation of the model’s outputs
3.4 Step 4: Calculation of the Sobol’s sensitivity indices
4 Results and discussion
4.1 Analysis of the model’s outputs
Parameter | ACID | ET | EM | POF | RIPM | WD |
---|---|---|---|---|---|---|
[mol H+ eq.] | [mol N eq.] | [kg N eq.] | [kg NMVOC eq.] | [kg PM2.5 eq.] | [m3 water eq.] | |
NFs as from Sala et al. (2015) | 2.36E + 10 | 8.76E + 10 | 8.44E + 09 | 1.58E + 10 | 1.93E + 09 | 4.06E + 10 |
Central tendency measures | ||||||
Arithmetic average | 2.66E + 10 | 1.03E + 11 | 9.46E + 09 | 1.57E + 10 | 1.93E + 09 | 1.55E + 11 |
Median
|
2.69E + 10
|
1.08E + 11
|
8.85E + 09
|
1.57E + 10
|
1.29E + 09
|
2.07E + 11
|
Dispersion measures | ||||||
Maximum | 3.51E + 10 | 1.32E + 11 | 1.09E + 10 | 1.67E + 10 | 6.08E + 09 | 2.19E + 11 |
Minimum | 2.22E + 10 | 8.70E + 10 | 8.39E + 09 | 1.45E + 10 | 7.00E + 08 | 3.84E + 10 |
Standard deviation | 2.78E + 09 | 1.30E + 10 | 9.79E + 08 | 5.64E + 08 | 1.49E + 09 | 8.14E + 10 |
Mean distance from the median | 2.22E + 09 | 1.06E + 10 | 9.63E + 08 | 3.69E + 08 | 9.18E + 08 | 5.94E + 10 |
Relative standard deviation | 10 % | 13 % | 10 % | 4 % | 77 % | 52 % |
Mean distance from the median divided by the median | 8 % | 10 % | 11 % | 2 % | 71 % | 29 % |
Ratios between the parameter and NF from Sala et al. (2015) | ||||||
Arithmetic average of model’s outputs | 1.13 | 1.18 | 1.12 | 0.99 | 1.00 | 3.82 |
NFs as median of model’s output | 1.14 | 1.23 | 1.05 | 0.99 | 0.67 | 5.09 |
Factor recommended for comparison | ||||||
Arithmetic average of model’s output + 1 standard deviation
|
2.94E + 10
|
1.16E + 11
|
1.04E + 10
|
1.62E + 10
|
3.43E + 09
|
2.37E + 11
|