Life Cycle Assessment (LCA) Impact Category Glossary

A glossary for the 16 impact categories in an LCA (EU PEF Standard) | Originally posted on Clean Agency's website

The world of life cycle assessments can get complex, and quickly. After the product system is defined at the end of the goal and scope phase, the LCA transitions into the life cycle inventory (LCI) phase. The LCI phase consists of collecting both foreground and background data on a product system, leaving the research team with potentially thousands of line items of technical environmental and product data. ?

Following the LCI phase, the environmental impact of the product system is assessed in the life cycle impact assessment (LCIA) phase. Before the assessment is run, it is important to categorize the LCI categories into impact categories.?

What are Impact Categories?

Impact categories group and summarize different elementary flows (environmental impacts) into categories to provide deeper insights about the environmental impact of the product or service. The process of turning elementary flows in a LCI into impact categories is referred to as characterization.?

In order for comparison and to simplify the reporting process, the impact categories have a common unit of measurement, known as a characterization factor.

For example, the characterization factor for global warming potential (climate change) is 1 kg of Co2e, meaning all impacts on climate change (CH4, etc.) are converted into a Co2e equivalent. Co2e represents the climate impact of the defined product system, instead of analyzing methane, nitrous oxide, and other greenhouse gases separately.?

How do you choose Impact Categories?

You might be wondering . . . how does one choose what impact categories to use for their life cycle assessment??

The selection of your life cycle impact assessment (LCIA) method will determine which impact categories are included and how calculations should be carried out. The standard that you choose to align your LCA with in the goal and scope phase will often point you in the right direction of which LCIA method to conduct your LCA with. ?

This page will serve as a glossary of common impact categories; including a definition, the unit of measure, and business activities that contribute to each category.?

The impact categories below are the 16 from the European Union’s Product Environmental Footprint (PEF) standard, one of the most widely used LCIA methods around the world.?

LCA Impact Category Glossary

Global Warming Potential (Climate Change)

Global Warming Potential (GWP) is the “climate change” impact category, converting the relative impact of different greenhouse gasses to a carbon dioxide equivalent (CO2e) to represent the climate impact caused by a product or service.?

Global Warming Potential (GWP) is measured in 1 kilogram of carbon dioxide equivalent (Co2e). For example, 1 kg of methane (CH4) is equivalent to 26-36 kg CO2e and 1 kg of nitrous oxide is equivalent to 265-298 kg of CO2e.?

To learn more about global warming potential, check out our blog on the subject here.?

Business activities that lead to greenhouse gas emissions include:

• Raw material extraction
• Manufacturing/processing
• Transportation & logistics
• Product use
• End-of-Life disposal

Ozone Depletion Potential

Ozone Depletion Potential is an impact category that measures a product system's potential impacts on depleting the stratospheric ozone layer, which protects the earth from ultraviolet radiation that can impact human and plant health.?

Ozone Depletion Potential is typically measured in kilograms of trichlorofluoromethane (Freon-11) equivalent, denoted by CFC-11 equivalent. This unit of measure is focused on quantifying the amount of Freon-11 and related ozone depleting emissions produced by a businesses, products, and packages supply chain.

Business activities that cause ozone depletion include:

• Refrigeration and air conditioning of facilities?
• Producing and using foam products for packaging?
• Producing aerosols, solvents, and other components with Freon-11
• Cleaning, Manufacturing, & waste industries that emit halons, methyl chloroform, and more?

Human Toxicity (Cancer Effects)

Human Toxicity (Cancer Effects) measures the potential of a product system to release externalities that can impact human health and cause cancer through absorption in air, water, soil, etc.?

In the EU’s PEF, Human Toxicity (Cancer Effects) is measured in Comparative Toxic Unit for humans (CTUh), which comes from the USEtox model. USEtox was developed by the United Nations Environment Program (UNEP) and the Society for Environmental Toxicology and Chemistry to provide a scientific model to measure “midpoint and endpoint characterization factors for human toxicological and freshwater ecotoxicological of chemical emissions in a life cycle assessment.”?

Business activities that can cause Human Toxicity (Cancer) include:

• Producing cleaning products, personal care products, and other products that contain potential cancer causing chemicals?
• Manufacturing waste and run-off that gets into water supply (arsenic)?
• Coal and fossil fuel production?
• Potential PFAS exposure through plastics, textiles & coatings
• Manufacturing and mining activities?

Human Toxicity (Non-Cancer Effects)

Similar to Human Toxicity (Cancer Effects), Human Toxicity (Non-Cancer Effects) measures the potential to release toxins into the air, water, and soil that can impact human health, but not cause cancer.?

Like Human Toxicity (Cancer), Human Toxicity (Non-Cancer) uses Comparative Toxic Unit for humans (CTUh), based on the same USEtox model.?

Business activities that can cause Human Toxicity (Non-Cancer) include:?

• Manufacturing and other activities that impact air quality (increase asthma rates, heart disease, etc.)
• Pollution of water supply?& microplastic exposure
• Production of chemicals and energy from fossil fuels?

Particulate Matter (PM)

Particulate Matter measures the potential of a product system to impact human health through emitting particulate matter and precursors like nitrous oxide and sulfur dioxide. The EU PEF page notes that since PM particles are small they are “more dangerous”, and they can penetrate deeper into the lungs and cause chronic health conditions with long-term exposure.?

In the PEF, the unit of measure for Particulate Matter (PM) is change in mortality due to PM emissions. This is measured in disease incidence per kg of PM2.5 emitted.?

?Business activities that can cause Particulate Matter (PM) include:?

• Construction and demolition practices?
• Vehicle emissions from transportation activities?
• Agricultural and industrial processes?
• Energy production

Ionizing Radiation

Ionizing Radiation is an impact category that represents the potential of a product system to expose humans to radioactivity, causing human health effects. The PEF notes that they only consider emissions that occur under “normal operating conditions”, not including accidents from facilities and nuclear sites.?

Ionizing Radiation uses the unit of measure of equivalent of kilobecquerels of Uranium 235 (kg U235 eq). Similar to GWP, kg U235 eq converts all the different ionizing traditions into a Uranium 235 equivalent.?

?Business activities that can cause Ionizing Radiation include:?

• Mining of uranium, thorium, and other radioactive materials?
• nuclear power plant operation?
• Improper handling of radioactive waste/materials

Photochemical Ozone Formation

Photochemical Ozone Formation is an impact category that measures a product system's potential to contribute to photochemical ozone formation (smog). PEF highlights that photochemical ozone formation in the troposphere (ground) harms animals and plants and causes respiratory problems in cities.?

Photochemical Ozone Formation is measured in equivalent of kilograms of Non-Methane Volatile Organic Compounds (kg NMVOC eq). Similar to other impact categories, kg NMVOC eq relies on converting all emissions that can cause photochemical ozone formation into a NMVOC equivalent.?

Business activities that can cause Photochemical Ozone Formation include:?

• Power plant emissions and fossil fuel energy production?
• Oil refineries, industrial plants, and industrial boilers (nitrous oxide emissions)
• Emissions from business fleet, transportation and machinery (nitrous oxide emissions)?
• Industrial activities and manufacturing

Acidification

Acidification is an impact category that considers the potential of a product system to produce emissions that absorb into the water and soil, harming terrestrial and aquatic ecosystems. PEF notes that Sulphur-based fuels are one of the main sources of acidification.?

Acidification is measured in equivalent of moles of hydron (mol H+ eq). Similar to global warming potential and others, this impact category converts all environmental impacts that have a potential to contribute to acidification to a hydron equivalent.?

Business activities that can cause Acidification include:

• The use of Sulphur-based fuels for transportation, etc.
• Combustion in the generation of electricity?
• Producing heat for buildings and facilities used for manufacturing?
• Oil refineries and manufacturing processes?

Eutrophication (Terrestrial)

Eutrophication (Terrestrial) is one of three eutrophication impact categories in the PEF that measures the potential of a product system to release substances containing nitrogen and phosphorus (macronutrients) into terrestrial ecosystems, leading to terrestrial eutrophication.?

Eutrophication leads to the growth of algae, which can block sunlight and starve submerged aquatic vegetation (SAVs) from oxygen, leading to dead zones caused by lower dissolved oxygen levels. In terrestrial environments, like grasslands, excess nitrogen exposure from air pollution can lead to overgrowth and undergrowth of certain plant species, hindering biodiversity and altering ecosystems.

Eutrophication (Terrestrial) is measured in equivalent of moles of nitrogen (mol N eq). Like other impact categories, this impact category converts all impacts that contribute to terrestrial eutrophication (phosphorus, etc.) into a mole of nitrogen equivalent.?

Business activities that can cause Terrestrial Eutrophication include:?

• Agricultural practices leading to fertilizer runoff, soil contamination, and more?
• Manure from livestock production and farming
• Wastewater discharge from facilities and municipalities?
• Deforestation and land use change (depletion of buffer zones)
• Livestock practices and overgrazing (depletion of buffer zones)
• Combustion of fossil fuels?

?Eutrophication (Marine)

Eutrophication (Marine) measures the potential of a product system to contribute to eutrophication (excess nitrogen and phosphorus exposure) in marine and coastal ecosystems. Eutrophication of marine ecosystems, primarily through excess nitrogen emissions, leads to dead zones and ecosystem disturbances in marine environments due to an over abundance of algae blooms.?

Eutrophication (Marine) is measured in kilograms of nitrogen equivalent (kg N eq), converting all impacts that contribute to marine eutrophication into a nitrogen equivalent, as nitrogen is the largest contributor to this type of eutrophication.?

Business activities that can cause Marine Eutrophication include:?

• Agricultural practices leading to fertilizer runoff
• Manure from livestock production and farming
• Wastewater discharge from facilities and municipalities?
• Combustion and industrial processes

Eutrophication (Freshwater)

?Eutrophication (Freshwater) is an impact category that measures a product system’s potential to contribute to eutrophication in freshwater environments. Similar to eutrophication in marine ecosystems, freshwater eutrophication causes dead zones and can lead to the death of species through overgrowth of harmful algae blooms.?

Eutrophication (Freshwater) is measured in equivalent of kilograms of phosphorus (kg P eq). This impact category is measured in phosphorus equivalents due to the fact that phosphorus emissions from sewage plants and agricultural practices are a large contributor to freshwater eutrophication.?

Business activities that can cause Freshwater Eutrophication include:?

• Agricultural practices leading to fertilizer runoff
• Manure from livestock production and farming
• Wastewater discharge from facilities and municipalities?
• Phosphorus emissions from industrial activities?

Ecotoxicity (Freshwater)

Ecotoxicity (Freshwater) is an impact category that measures the potential of a product system to contribute to toxic impacts on freshwater ecosystems, this mainly occurs through the use of chemicals and other toxic components. Freshwater ecotoxicity can impact individual species, and entire ecosystems—leading to biodiversity loss and potential species extinction.?

Ecotoxicity (Freshwater) is measured in Comparative Toxic Unit for ecosystems (CTUe), based on the same USEtox model of the two human toxicity impact categories.

Business activities that can cause freshwater ecotoxicity include:?

• Chemical usage in agricultural processes?
• Sewage and waste water treatment operations?
• Fossil fuel plants and production?
• Certain chemical products and manufacturing processes

Land Use

Land Use measures the use and transformation of land throughout value chain processes, which is measured based on four soil properties. PEF notes that the impact of land use and transformation include loss of biodiversity, reduced soil quality, erosion, increased run off and pollution of externalities in other impact categories, and more. ?

Land Use is measured by a “composite indicator” that is based on four soil properties, which is measured in points (Pts):

• Biotic production?
• Erosion resistance?
• Groundwater regeneration?
• Mechanical filtration

Business activities that lead to Land Use include:?

• Transformation of land for agriculture (monocultures), facilities, mining, etc.?
• Deforestation and agricultural practices?
• Pollution that negatively impacts four soil properties & overall soil health

Water Use

Water Use is an impact category that measures the potential of a product system to contribute to the depletion of water resources (lakes, rivers, groundwater), considering the “availability and scarcity of water” in production regions.?

Water Use is measured in cubic meters (m3) of water use in relation to the “local scarcity of water.”?

Business activities that lead to Water Use include:?

• Agricultural and live stock production?
• Textile and cotton production?
• Mining raw materials?
• Manufacturing?
• Energy and heat production?

Resource Use (Fossils)

Resource Use (Fossils) is an impact category that measures the extraction of fossil fuels related to a defined product system. PEF lists coal, oil, and natural gas as resources that fall under the category.

Resource Use (Fossils) is measured by converting the “amount of materials” contributing to this impact category to MJ, a “megajoule” or 1 million joules.?

Business activities that lead to the use of Fossil Fuel resources include:?

• The extraction of coal, oil, and natural gas?
• Energy and industrial applications that rely on fossil fuel extraction (plastic production)

Resource Use (Minerals & Metals)

Resource Use (Minerals & Metals) is an impact category that measures the extraction of finite minerals and metals related to a product system. PEF highlights that similar to fossil fuels, certain minerals and metals (gold, silver, aluminum, etc.) need to be extracted responsibly in order to ensure supply for future generations.?

Resource Use (Minerals & Metals) is measured by converting the “amount of materials” contributing to this impact category to kilograms of antimony equivalent (kg Sb eq). Antimony is used as the unit of measure due to its use in products like batteries, flame retardants, and more.?

Business activities that lead to the use of Mineral & Metal resources include:?

• Mining and extraction of metals for electronics, etc.?
• Mining for production of aluminum and metal products, packaging, etc.?
• Mining of minerals and metals for raw materials for various industries

That concludes all 16 impact categories under the PEF! To read more about LCA-related topics, visit our blog here!

Conduct a Life Cycle Assessment with Clean Agency

With 16 different environmental impact categories to consider and quantify, many of which are likely new even for seasoned sustainability professionals, the life cycle assessment (LCA) process is no easy feat.?

At Clean Agency, we have 20+ years of experience conducting product and comparative life cycle assessments (LCAs) for top brands including Allbirds, Nestle, Gerber, Reformation, and more.?

Looking to conduct an LCA to identify hotspots and see how your product or packaging scores on 16 impact categories? Reach out to [email protected]?

Learn more about our LCA services here!?