Emissions Factors Toolkit

The Emissions Factors Toolkit (EFT) is published by Defra and the Devolved Administrations to assist local authorities in carrying out Review and Assessment of local air quality as part of their duties under the Environmental Act 1995.

The EFT allows users to calculate road vehicle pollutant emission rates for NOx, PM10, PM2.5 and CO2 for a specified year, road type, vehicle speed and vehicle fleet composition.

The EFT is updated periodically due to updates to underlying data including vehicle fleet composition and emissions factors. Users are therefore advised to check this page regularly to ensure they are using the most up to date version of the tool for their studies.

The current version of the EFT (version 10.1) can be downloaded here (XLSB, 5.9MB).

The accompanying EFT User Guide (PDF, 0.8MB, 41 pages) explains in detail the methodology, datasets and assumptions used in the development of the EFT. It consolidates previously available information and guidance on the use of the EFT, and provides information regarding previous versions (changes and updates).

The previous version of the tool is available below:

Local authorities are advised to use the latest version of the EFT for all future work. However, if earlier versions of the EFT are required please contact the Helpdesk for further assistance.

Please Note: The default fleet projections in EFT v10.1 are based on fleet growth assumptions which were current before the Covid-19 outbreak in the UK. In consequence, default fleet outputs from the tool do not reflect short or longer term impacts on emissions in 2020 and beyond resulting from behavioural change during the national or local lockdowns.