176 Note: The list of air emissions estimated from the LCI phase can be expanded beyond what is presented in Table 6. However, these emissions were chosen to compare with the results of the DAE method. In addition to differences in scope, there are further differences in the EFs used to estimate CO2, NOx, and TSP emissions from resource consumption. To illustrate further, the EFs used to estimate emissions from diesel consumption are chosen, since diesel consumption is the major contributor to emissions and the most impact indicators in LCA. Figure 8 – Steps involved in translation of LCI results to impact indicator (Baumann & Tillman, 2004). Table 6 – Emissions to air estimated from DAE and LCI for the cradle-to-gate system boundary. Emissions Unit DAE LCI phase Difference CO2 kg CO2/tonne of aggregates 8.79E-01 1.40E+0 0 5.16E-01 NOx kg NOx/tonne of product 9.90E-03 8.69E-03 -1.21E-03 TSP kg TSP/tonne of product 1.32E-01 9.80E-06 -1.32E-01 PM10 kg PM10/tonne of product 4.44E-02 1.08E-05 -4.44E-02 PM2.5 kg PM2.5/tonne of product 7.36E-03 4.65E-04 -6.90E-03 NOx SO2 HCl etc. Characterisation results (Impact indicator) Life Cycle Inventory results CO2 CH4 NOx SO2 CFCs P NH3 HCl etc. Classification of inventory results CO2 CH4 CFCs etc. NOx NH3 P etc. Global Warming Eutrophication Acidification
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