The OECD Task Force on Pollutant Release and Transfer Registers (PRTRs), which is part of the Environment, Health and Safety programme has developed a clearinghouse of guidance manuals/documents of release estimation techniques for the principal pollutant release and transfer registries developed by OECD member countries. The manuals and documents include descriptive information on the sources of pollution and the pollutants that are released into the environment, as well as information on emission factors, mass balance methods, engineering calculations and monitoring information.
The OECD Resource Centre for Release Estimation Techniques (RETs) can be accessed by using this link