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Characterisation factors for default impact assessment categories

This is a list of characterisation models and factors to use for the default environmental impact categories. This page is updated on a updated on a regular basis based on the latest developments in LCA methodology and ensuring the market stability of EPDs. The latest update to the recommendations was made 2018-05-30 (POFP) and 2018-06-08 (Water Scarcity Footprint).

Default environmental impact categories

The characterisation models and factors to use for the default impact categories are available in the table below:  

Impact category (Unit)Characterisation factorsOriginal reference(s)Examples

Global warming potential


(kg CO2 eq.)

GWP100, CML 2001 baseline Version: January 2016.

IPCC (2013)

1 kg carbon dioxide = 1 kg CO2 eq.


1 kg methane = 28* kg CO2 eq.


1 kg dinitrogen oxide = 265 kg CO2 eq.

Acidification potential


(kg SO2 eq.)

AP, CML 2001 non-baseline (fate not included), Version: January 2016.


Please notice the use of non-baseline characterisation factors for acidification potential.

Hauschild & Wenzel (1998) 1 kg ammonia = 1.88 kg SO2 eq.
1 kg nitrogen dioxide = 0.7 kg SO2 eq.
1 kg sulphur dioxide = 1 kg SO2 eq.

Eutrophication potential


(kg PO43- eq.)

EP, CML 2001 baseline (fate not included), Version: January 2016. Heijungs et al. (1992)

1 kg phosphate = 1 kg PO43- eq.


1 kg ammonia = 0.35 kg kg PO43- eq.


1 kg COD (to freshwater) = 0.022 kg kg PO43- eq.

Photochemical oxidant formation potential


(kg NMVOC eq.)

POFP, LOTOS-EUROS as applied in ReCiPe 2008

Van Zelm et al 2008


ReCiPe 2008

1 kg carbon monoxide = 0.046 kg NMVOC eq.


1 kg nitrogen oxides = 1 kg NMVOC eq.

Abiotic depletion potential – Elements


(kg Sb eq.)

ADPelements, CML 2001, baseline

Oers, et al (2002)

1 kg antimony = 1 kg Sb eq.


1 kg aluminium = 1.09 * 10^-9 Sb eq.

Abiotic depletion potential – Fossil fuels


(MJ, net calorific value)

ADPfossil fuels, CML 2001, baseline Oers, et al (2002)

1 kg coal hard = 27.91 MJ


1 kg coal soft, lignite = 13.96 MJ

Water Scarcity Footprint (WSF)


(m3 H2O eq)

AWARE Method:   WULCA Recommendations  on characterization model for WSF 2015, 2017.


CF at country level can be download (Excel files) from: www.wulca-waterlca.org/aware.html


Cut-off rules can have important implications on the results. WULCA applies as cut-off rule: the maximum value for CF is set to 100 when Demand ≥ Availability  (AWARE100).


(But, it has been proposed also two other cut-off rules for the AWARE Methods:

- Maximum CF of 10 (AWARE10);

- Maximum CF of 1000 (AWARE1000))

Boulay et al (2017)

AWARE method is based on 1/AMD(*), the inverse of the difference between water availability per area and demand per area(**).


It quantifies the potential of water deprivation, to either humans or ecosystems, and serves in calculating the impact score of water consumption at midpoint in LCA or to calculate a water scarcity footprint as per ISO 14046. It is based on the available water remaining (AWARE) per unit of surface in a given watershed relative to the world average, after human and aquatic ecosystem demands have been met.


(*) 1/AMD:  the inverse of [Availability - Demand ]


(**) What is the potential to deprive another user (human or ecosystem) when consuming water in this area?”


The resulting characterization factor (CF) ranges between 0.1 and 100, and can be used to calculate WSF as defined in the ISO standard 14046:2015.


The local AWARE factor is meant to be multiplied with the local water consumption inventory. 


Example:  582 m3 H2O consumed per ton of grapes produced in Mendoza, Argentina :

WSF = 582 m3H2O x 54.15 (CFAgriAWARE100) = 31,518 m3eq/ton grape

* Please note that the original source, IPCC (2013), differentiates "Fossil methane" from methane.

For construction product EPDs compliant with EN 15804, Table 3 in EN 15804 (“Parameters describing environmental impacts”) shall be applied in the PCR instead of the indicators listed above. Characterisation factors are available in Annex C of the standard.

To find corresponding methods available in your LCA software, such as SimaPro, GaBi or openLCA, please see the documentation or contact your LCA software provider. To see the compliance of different versions of the CML-IA, see the version history available on their website.


The source and version of the characterisation models and the factors used shall be reported in the EPD. Alternative regional life cycle impact assessment methods and characterisation factors are allowed to be calculated and displayed in addition to the default list. If so, the EPD shall contain an explanation of the difference between the different sets of indicators, as they may appear to the reader to display duplicate information.

Additional indicators


To better characterise the environmental performance of a product category, the PCR shall indicate the mandatory or voluntary use of other indicators of potential impacts. All environmentally-relevant indicators for the product category shall be included. Examples of such environmental impact categories to include in the PCR are:

  • emission of ozone-depleting gases, and 
  • land use and land use change.

Examples of reports that provide recommendations on impact categories and indicators are UNEP/SETAC Global Guidance for Life Cycle Impact Assessment Indicators and the ILCD Recommendations for Life cycle impact assessment in the European context.