177 Figure 9 – Scope of the DAE and LCA. Additionally, diesel consumption is considered in both DAE and LCA. From Table 6, it can be observed that there are minor differences among the EFs used in the two methods. Although the differences in EFs between the two methods are small, the differences in the total emissions estimated for the cradle-to-gate system boundary are larger. This is related to the scope of the methods. CONCLUSION This study assesses the cradle-to-gate aggregate production system boundary, encompassing operations such as rock material extraction, material handling, and the production process. DAE is used to estimate air emissions from on-site operations, and LCA to estimate environmental impacts covering on-site operations and the supply chain of consumed resources. The results from both methods indicate that the majority of the emissions and impacts originate during the material handling operation. For DAE, internal transport of this category gives the largest share. When analyzing the results, it was identified that the environmental impacts and emissions estimated from LCA and DAE, respectively, are not directly comparable. As a result, the raw elementary flow estimated during the LCI phase of the LCA was used to compare with DAE results. Upon comparison, differences were identified; for instance, CO2 emissions calculated in the LCI phase were higher than those calculated in the DAE. For TSP and PM emissions, DAE estimates higher values. The differences were attributed to the scope and the Production of a resource Transport Impact indicator GWP ODP AP EP POCP ADP PM On-site consumption CO2 NOx PM Material and Energy inputs Emission Material and Energy inputs CO2 Carbon dioxide NOx Nitrogen oxides TSP Total Suspended Particle PM ParticulateMatter( 10 mand 2.5 m) This box indicates the scope of LCA This box indicates the scope of the DAE estimation Method in the context of this study This box accounts for the supply chain of a resource Resource TSP Resource Emission Factors Characterization Factors (Environmental Footprint 3.0) etc. Waste Emissions Phase Change (e.g., Diesel combustion) No phase change (e.g., Rubber waste, lubricant waste, etc.) Emissions Transport and Waste Treatment Table 7 – EFs used in DAE and LCA for estimating emissions from diesel combustion. Resource Emissions Unit EFs in DAE EFs in LCA Diesel CO2 kgCO2/kg of diesel 3.160 3.004 NOx kg NOx/kg of diesel 0.033 0.024 PM2.5 kg PM2.5/kg of diesel 0.002 0.001
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