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Environmental Impact categories

The PEF (Product Environmental Footprint) LCA (Life Cycle Assessment) method introduces 16 environmental impact categories where climate change is one of them. These are all approaches in which manufacturing and production of goods and services harm the environment. When we measure a product’s influence on the impact categories, we consider the whole product life cycle. On this page, we explain all 16 categories briefly.

Furthermore, we introduce you to the terms normalization and weighting, and explain the PEF single score.

climate change, PEF impact category

Climate change

How the product adds to global warming and the planet getting hotter.

Unit: (CO2eq). The global warming potential of all greenhouse gas emissions is measured in kg CO2eq, meaning that they are compared to the amount of the global warming potential of 1 kg CO2.

particulate matter PEF impact category

EF-particulate matter

How many tiny harmful particles is released into the air in connection to the product.

Unit: Disease incidences per kg of PM2.5 emitted (2.5 refers to the size of the particle in micrometers). The potential impact is measured as the change in human deaths caused by particulate matter (PM).

Water use

Assesses the deprivation of freshwater resources associated with a product.

Unit: (m3). The potential impact is expressed in cubic meters of water being deprived in an area. The number relates to the local scarcity of water and not only the consumed amount of water. In other words, how much water is missing after water has been used in relation to a product.

Resource use, fossils, PEF impact category

Resource use, fossils

Depletion of non-renewable resources like fossil fuels deprives future generations of them.

Unit: (MJ) The number of materials contributing to resource use, fossils, are converted into megajoule, which is an inherent energy in fossil fuels (oil, gas, etc.).

Land use

Soil quality loss measures the amount of land and soil used, blocked, ruined, affected, or changed in negative ways in relation to a product.

Unit: (Pts). This is a composite indicator measuring impacts on four soil properties (biotic production, erosion resistance, groundwater regeneration, and mechanical filtration), expressed in points.

Resource use, minerals & metals

Extracting a high amount of resources today will force future generations to extract lower concentrations or lower value resources. Use resources wisely.

Unit: (kg Sbeq). The number of materials contributing to resource depletion is converted into equivalents of kilograms of antimony. It is the ratio between the annual production of the resource and the known global reserve that is considered in this measurement.

Ozone depletion potential

Whether the product harms the protective ozone layer around Earth.

Unit: (kg CFC-11eq). The potential impacts of all relevant substances for ozone depletion are converted to their equivalent of kilos of trichlorofluoromethane, also called Freon-11 and R-11.

Accidification

Indicator of the potential acidification (turning sour) of soils and water.

Unit: (mol H+eq) The potential impact of substances contributing to acidification is converted to the equivalent of moles of hydron concentration.

ionizing radiation, PEF impact category

Ionizing radiation

Assesses whether the product causes humans to be exposed to any radioactive substances.

Unit: (kgU235eq). The potential impact on human health of different ionizing radiations is converted to the equivalent of kilograms of Uranium-235.

photochemical ozone formation, PEF impact category

Photochemical ozone formation

Measures the amount of toxic ozone that a product causes to be released in the lower atmosphere.

Unit: (kg NMVOCeq). The potential impact of substances contributing to photochemical ozone formation is converted into the equivalent of kilograms of Non-Methane Volatile Organic Compounds.

terrestrial eutrophication, PEF impact category

Eutrophication terrestrial

Overfertilization of the soil resulting in an excessive amount of nutrients pushing the ecosystem out of balance.

Unit: (mol N eq). The potential impact of the concentration of substances contributing to terrestrial eutrophication is converted to the equivalent of moles of nitrogen.

marine eutrophication, PEF impact category

Eutrophication marine

Overfertilization of the marine resulting in an excessive amount of nutrients pushing the ecosystem out of balance.

Unit: (kg N eq). The potential impact of substances contributing to marine eutrophication is converted to the equivalent of kilograms of nitrogen.

freshwater eutrophication, PEF impact category

Eutrophication freshwater

Overfertilization of freshwaters resulting in an excessive amount of nutrients pushing the ecosystem out of balance.

Unit: (Kg P eq). The potential impact of substances contributing to freshwater eutrophication is converted to the equivalent of kilograms of phosphorus.

human toxicity cancer PEF impact category

Human toxicity, cancer

Impact on human health caused by absorbing substances through the air, water, and soil.

Unit: Comparative Toxic Unit for humans (CTUh). The measurement considers the estimated increase in mortality in the total human population per unit mass of different chemicals emitted.

ecotoxicity freshwater, PEF impact category

Ecotoxicity freshwater

The direct impact of toxic substances on freshwater ecosystems, including lakes, rivers, groundwater reserves, etc.

Unit: Comparative Toxic Unit for ecosystems (CTUe). It is the estimate of the potentially affected fraction of species (PAF) integrated over time and volume, per unit mass of a chemical emitted.

human toxicity non-cancer, PEF impact category

Human toxicity, non-cancer

Impact on human health caused by absorbing substances through the air, water, and soil.

Unit: Comparative Toxic Unit for humans (CTUh). The measurement considers the estimated increase in mortality in the total human population per unit mass of different chemicals emitted.

Normalization

Normalization in the context of PEF impact categories means that we convert different kinds of environmental impacts (such as carbon emissions, water use, toxicities, etc.) into a common language, so we can compare them more easily.

Thought experiment

Imagine you are baking a cake. The recipe contains ingredients, that are measured in different units, such as kilograms, liters, tablespoons, and pieces.
You are on a budget and want to know which ingredients constitute the largest share of the price for the whole cake.
To figure this out, you normalize the units (kilograms, liters, tablespoons, etc.) by converting them into the same reference unit, namely price. If you used two eggs for the cake and you paid 5 euros for 10 eggs, then the eggs in the cake cost (5/10*2) 1 euro. Maybe you also paid 5 euros for a bag of vanilla sugar with 100 grams but only used 5 grams for the cake – that’s only 0,25 euros. You continue this method with all the ingredients. Let’s say you find out that the cake has a total price of 10 euros. Then the eggs make up 10% of the total costs, while the vanilla sugar constitutes 2,5%. This enables you to compare the different ingredients and see which is the most expensive ingredient in your cake.

Common reference system

In the context of life cycle assessment (LCA) and environmental impact assessment, normalization is a step we use to provide context and perspective to the results of the environmental impact categories.

Normalization involves comparing the environmental impacts of a product or process to a reference or baseline. This reference can be a specific benchmark, an industry average, or some other meaningful standard. Normalization aims to help us and you understand the relative significance of the environmental impacts of the various impact categories.

The reference system of PEF

The common reference in the PEF LCA framework is a global average person’s emissions in 1 year. So, the result of each environmental impact category must be converted into what it corresponds to in relation to an average global person’s yearly emissions.

For example, in an LCA using the PEF methodology, we express the environmental impact of a product in 16 different categories. These are all measured in different units. For example, the climate impact is measured in carbon dioxide equivalents (CO₂eq) emissions, and ozone depletion potential is measured in trichlorofluoromethane equivalents (kg CFC-11eq). To be able to know which impact is greatest, we must convert the two numbers into the same unit. We do this by comparing the results to the yearly emissions of an average global person, which is the common reference unit.

Normalization is an important step and valuable tool in LCA because it provide us with a way to compare the impact of different categories measured in different units. It makes it possible to see which categories impact the environment the most.

Weighting

Think of the weighting of PEF impact categories like assigning importance to different aspects of a product’s impact on the environment and evaluating how much you can trust the figures.

Thought experiment

Imagine you’re judging a cooking competition with three categories: taste, presentation, and creativity. You decide that taste is the most important, so you give it a higher weight, let’s say 50%, while presentation and creativity are less critical, so you give them lower weights, e.g., 25% each.

Different levels of significance

In the context of PEF impact categories, weighting is a process we use to assign different levels of importance to the various environmental impacts. Scientists, researchers and the EU have assigned a specific weight to each of the categories. They have based their weighting on the overall importance, urgency, impact scale, and calculation accuracy (robustness) of each category. The weight is called the weighting factor.

Weighting is a valuable step when we work with so many different types of environmental impacts. It allows us to prioritize and focus our efforts on the most significant environmental impact categories, helping decision-makers identify which environmental categories are most important to reduce first. Usually, climate change in terms of global warming has the highest score in a normalized and weighted set of environmental parameters calculated according to PEF rules, but for some materials or production processes other environmental effects might be more harmful.

Weighting of PEF impact categories

In PEF, different aspects of a product’s impact on the environment (like climate emissions, water use, and resource depletion) are like the cooking competition categories. Weighting means deciding how much each of these environmental aspects counts toward the overall environmental performance.

EU has decided on the following weighting of all the impact categories:

Table weighted factor

PEF single score

A single score in this context refers to a product’s overall environmental assessment. The single score is a sum of all the normalized and weighted numbers that a product has scored in each of the impact categories.

So, building on top of all the individual calculations from each impact category, we are able to obtain one figure that expresses the overall environmental impact of a product. This means that we can compare the total environmental impact of different products. Ultimately, it allows us as consumers to make more responsible purchasing decisions. Due to the PEF single score, for the first time, we have a scientific method that allows for comparing and evaluating easily the total environmental performance of two products. The potential effects of this are huge and can be a massive driver for a more environmentally sustainable lifestyle.

The Målbar tool only calculates on CO2eq and climate impact of products.

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