Example LCA Study, Part III -- Comparison of Two Air Dusters

In Part II, I listed all the data used in SimaPro for the analysis and also included diagrams for the system boundaries.

In this part, Part III, I share the results of the study. I just wanted to note again that the results of this study have not been peer-reviewed and are not intended to be used in decision-making processes.

To recap the process, for each duster, I entered my data into SimaPro and chose the output to be normalized results. After running the program (analyzing the data), I then exported the data from SimaPro to an Excel file that included a table of results: Rows of impact categories and columns of materials/processes. For each impact category and material/process there is a corresponding cell with a number representing the impact. In order to adjust this data to the functional unit, I divided each cell by the number of two-minute dusting sessions I calculated in Part I (12.5 for the gas duster and 96 for bulb duster). I was then free to visualize the data any way I wanted to. Here is how we visualized the data for class:

Figure 3. Impacts of the dusters by impact category when considering the number of two-minute dusting sessions per lifetime of each product (12.5 for the gas duster and 96 for the bulb duster).

Figure 4. Impacts of the dusters by life cycle stage when considering the number of two-minute dusting sessions per lifetime of each product (12.5 for the gas duster and 96 for the bulb duster). It should be noted that use impacts were not included in the study boundary.

You can see from Figures 3 and 4 that the gas duster has a greater impact over the lifetime of the products. Freshwater ecotoxicity is the biggest impact for the gas duster and the life cycle stage with the greatest impact is the material production phase.


Because the impact of the bulb duster was so small compared to the gas duster, it was difficult to see in the above graphs the details for the bulb duster. Therefore, I made additional graphs that just show either the gas duster or the bulb duster and how big of an impact each material or process was. Grayed out text in the graph legends indicate that the amount was so small that it doesn't visually show up on the graph.

Figure 5. Relative impacts of each of the processes or materials in the making of the gas duster. Grayed out text indicates that the impact was too small to show up on the graph.

Figure 6. Relative impacts of each of the processes or materials in the making of the bulb duster. Grayed out text indicates that the impact was too small to show up on the graph.

In Figure 5, we see that the creation of the steel for the gas duster can and the creation of the gas create the biggest impact. In Figure 6, we see that the landfilling of the bulb duster and the creation of the rubber bulb (rubber + molding) creates the biggest impact.