Carbon References

Welcome to the carbon footprint references page! The carbon footprint includes greenhouse gas emissions in the form of CO2, CH4, N2O, and refrigerants/chemicals. The calculation of the carbon footprint follows the guidelines from the GHG Protocol. Whenever possible, the same data sources are used for both the carbon and nitrogen footprint for alignment in methods and system bounds. The main source for the carbon footprint emission factors is the EPA US GHG Inventory. Additional details about the carbon footprint can be found on the Training page. As always, please contact us at with any questions.

General information on emission factor versions

2022 version of emission factors: Recommended

2021 version of emission factors: Recommended

2020 version of emission factors (outdated)

2019 version of emission factors (outdated)

2017 and 2018 versions of emission factors (outdated)