How do you select and apply the relevant impact categories and indicators for LCA of packaging materials?

1 Define the goal and scope

The first step of any LCA is to define the goal and scope of the study, which includes the functional unit, the system boundaries, and the data quality requirements. The functional unit is the reference unit that describes the function or service of the product or system, such as the amount of goods protected or transported by the packaging material. The system boundaries define the processes and activities that are included or excluded from the LCA, such as the production, transportation, use, and disposal of the packaging material. The data quality requirements specify the criteria for selecting and validating the data sources and methods for the LCA, such as the reliability, completeness, consistency, and transparency of the data.

2 Select the impact categories and indicators

The second step of any LCA is to select the impact categories and indicators that are relevant and meaningful for the goal and scope of the study. These categories are the environmental issues that are affected by the product or system, such as global warming, acidification, eutrophication, or human health. The indicators are quantifiable measures that represent the potential contribution of the product or system to the impact categories, such as carbon footprint, acidification potential, eutrophication potential, or disability-adjusted life years. When selecting these categories and indicators, criteria such as relevance, completeness, consistency and transparency should be taken into consideration. Relevance refers to reflecting the most significant environmental impacts of the packaging material and its life cycle stages, as well as the interests and expectations of stakeholders and decision-makers involved in the LCA. Completeness implies covering all relevant environmental aspects and dimensions of the packaging material and its life cycle stages, such as emissions, resources, land use or biodiversity. Consistency means being compatible and comparable with each other and with the functional unit and system boundaries of the LCA, as well as with data quality requirements and LCA standards and guidelines. Transparency requires clearly defining and documenting sources, assumptions, uncertainties and limitations of data and methods used for the LCA.

3 Apply the impact assessment methods

The third step of any LCA is to apply the impact assessment methods that calculate and aggregate the indicators for each impact category based on the inventory data of the product or system. This includes materials, energy, water, emissions, or wastes. The impact assessment methods are models and factors that translate the inventory data into indicators such as global warming potential, acidification factor, eutrophication factor, or exposure-response function. The application of these methods should involve classifying the inventory data according to their causal relationship with environmental issues, characterizing them with factors that reflect their contribution to the impact categories, normalizing them with reference values for the impact categories, and weighting them with factors that represent their relative importance or preference.

4 Interpret and communicate the results

The fourth and final step of any LCA is to interpret and communicate the results of the impact assessment in a way that supports the goal and scope of the study. This should involve identifying the main contributors of environmental impacts, comparing the impacts of different packaging materials or alternatives, improving the environmental performance of packaging materials, and communicating the findings to relevant stakeholders. This could be done through reports, labels, dashboards, or websites.