IMPACT CATEGORIES CONSIDERED IN THE CONTEXT OF LIFE CYCLE ASSESSMENTS AT EVONIK

Global Warming Potential (GWP) is a relative measure of how much heat a greenhouse gas traps in the atmosphere, leading to climate change. It compares the amount of heat trapped by the mass of a greenhouse gas to the amount of heat trapped by a similar mass of carbon dioxide over a defined period of 100 years. Greenhouse gases that are anthropogenically caused or increased, include carbon dioxide, methane and chlorofluorocarbons (CFC). GWP is expressed as a factor of carbon dioxide in kg CO₂­equivalents.

• Global Warming Potential (excluding biogenic carbon) – is developed to compare the global warming impact of different gases. Greenhouse gases serve as a blanket in our atmosphere and therefore prevent energy from escaping into space and insulate the Earth, which in the end warms the earth. But different greenhouse gases can have different effects on the earth's warming. This parameter specifically measures how much energy a gas will absorb over a given period of time, in relation to 1 kg of CO₂. The larger the GWP, the more that given gas warms the Earth compared to CO₂ over a given time.
• Global Warming Potential (including biogenic carbon) – the difference between this parameter and the former is that this parameter includes the carbon that is stored in biologic materials such as plants or soil as well as emissions released from these materials (e.g. by burning wood).
• Emissions from Land Use Change (LUC) - Carbon stocks represent the quantity of carbon stored in different pools, including the soil organic matter, above- and below-ground biomass, dead organic matter, and harvested wood products. By definition, an increase in carbon stocks is a biogenic CO₂ removal and a decrease in carbon stocks is a biogenic CO₂ emission. Therefore, land use change can cause emissions.

Breakdown of GWP into Separated Emissions Values according to ISO 14067

• Aircraft emissions – this indicator is an important environmental impact category of air travel as the emissions of airplanes include carbon dioxide (CO₂), nitrogen oxides (NOx), sulfur oxides (SOx), particulate and water vapor.
• Biogenic GHG emissions – are emissions of Greenhouse gases (GHG), that occur naturally due to biological processes, such as decomposition of organic matter. These gases include methane (CH₄) and carbon dioxide (CO₂), which contribute directly to climate change.
• Biogenic GHG removal – is the process of removing carbon dioxide (CO₂) from the atmosphere through biological processes, such as photosynthesis in plants and trees. This parameter can reduce the CO₂ content in the atmosphere and can help mitigate climate change.
• Emissions from land use change – describes the process by which humans transform the natural landscape for economic activities. These emissions are mainly caused by the change from a natural ecosystem to agricultural, urban or industrial land uses. This can lead to the release of carbon stored in vegetation and soils, as well as the loss of biodiversity.
• Fossil GHG emissions – include the greenhouse gas emissions from the combustion of fossil fuels, such as coal, oil and gas, to generate energy. This indicator is a direct contributor to climate change as it represents the release of carbon into the atmosphere.

is the formation of acidifying substances through oxidation or hydrolysis or other transformation of gases, such as sulphur dioxide in sulphuric acid. This affects both terrestrial and aquatic ecosystems since those substances can be deposited as dust (dry) or dissolved in precipitation (wet). The unit of measurement for Acidification is Mole of H⁺-equivalents.

is the term and quantification of all non-human life threatened by chemical emissions. Ecotoxicity impacts refer to air, soil, freshwater and marine water. The unit of measurement for Ecotoxicity is the so-called comparative toxic unit for ecotoxicity impacts (CTUe).

measures nutrients emitted to ecosystems (terrestrial, marine, freshwater). Emitted nutrients containing nitrogenous and phosphorous compounds accelerate biological activity, leading to undesirable shifts in species compositions. This in turn results in a depressed oxygen level and may lead to a collapse of the ecosystem. The Eutrophication Potential is expressed using the reference unit kg PO₄‑equivalents. The fraction of nutrients reaching the freshwater end compartment is expressed in kg P‑equivalents. The fraction of nutrients reaching a maritime end compartment is expressed in kg N‑equivalents.

is the term and quantification of chemical emission resulting in toxicological impacts on human health. Therefore, three aspects must be considered: Chemical fate, human exposure and toxicological effects. The unit of measurement for Ecotoxicity is the so-called comparative toxic unit for human toxicity impacts (CTUh).

measures the emission of radionuclides, linked to the damage of human health and ecosystems. Radionuclides are radioactive materials, whose excess energy is emitted in form of particles or electromagnetic waves, thus having the ability to ionize and change atoms and potentially damaging cells. The unit of measurement for Ionizing radiation is the equivalent uranium radiation measured in kilo Becquerel (kBq U235‑equivalent).

are a quantification of land surfaces used by humans (industry, agriculture, housing, infrastructure). Growing anthropogenic land use is considered to be a threat to species and ecosystems. Besides, land surfaces are partly transformed (Land Use Change, LUC), as through e.g. sealing or monocultures, potentially leading to undesirable effects in other of the named impact categories. 
Land Use Impacts are quantified according to the LANCA model. The impact of Land use impacts depends on the effects a land use has on the following indicators: erosion resistance, mechanical filtration, groundwater regeneration and biotic production on the occupied land. The unit of measurement for Land Use Impacts is Points (Pt). The unit point is calculated based on a normalization of the four previously described indicators. More points mean a higher environmental impact caused by land use change.

is the depletion of ozone in the stratosphere of the earth leading to increased fractions of solar UV-B radiation arriving at the earth surface. This increased UV-B radiation may harm human and animal health as well as ecosystems. Ozone Layer Depletion Potential is measured equivalent to the ozone depleting gas CFC‑11 and thus the reference unit is kg CFC‑11‑equivalent.

describes the effect of fine particles <2.5 µm (PM 2.5) emitted directly as primary particles or indirectly via precursors like NOx or SO₂ as secondary particles. The environmental impact of particulate matter is measured in disease incidences.

is the measure of substances (e.g. nitrogen oxides and non-methane volatile organic compounds) emitted to the atmosphere, forming photo-oxidants (e.g. ozone) in the presence of sunlight. Whereas in the higher atmosphere, ozone protects against ultraviolet (UV) light, low level ozone is implicated in diverse negative impacts such as crop damage, increased incidence of asthma and other respiratory complaints. Photochemical ozone creation potential is expressed using the reference unit of non-methane volatile organic compound‑equivalents (NMVOC‑eq.).

Resource Use fossil indicates the depletion of natural fossil fuel resources, and it is measured in megajoules.

Resource Use minerals and metals describes the depletion of resources. Resource Use minerals and metals is measured in antimony‑equivalents.

is a value dependent on regional and temporal scale. It can be measured as a ratio or subtraction of water availability to water consumption (including water pollution form case to case). The most commonly used methodology is AWaRe, representing the relative Available WAter REmaining per area in a watershed, after the demand of humans and aquatic ecosystems has been met.

measures water withdrawn from ground or surface bodies and thus causing freshwater depletion. The blue water inventory of a process includes all freshwater inputs but excludes rainwater. It includes the sum of blue water consumed (in kg) while the availability of water in the specific region is not considered.