Estimating releases from non-point sources
Data on releases from non-point sources are developed by the agency responsible for each non-point source. When estimating releases from non-point sources, it is important to first identify which non-point sources will be included in the PRTR. Non-point sources relevant to a PRTR may include:
- Area sources, including
- Groups of small stationary point source facilities that do not exceed the reporting thresholds for the PRTR (e.g. a single small dry cleaner may not qualify for PRTR reporting as a point source, so the small dry cleaners in an area may be grouped together as an area source); or
- Numerous very small sources spread over extensive areas (e.g. residential wood combustion, pesticide use);
- Mobile sources – non-stationary sources (e.g. automobiles, aircraft);
- Biogenic sources – biological non-anthropogenic sources (e.g. microbial activity); and
- Geogenic sources – other non-anthropogenic sources (e.g. volcanoes).
For each non-point source to be included in the PRTR, the responsible agency will need to identify the data sources and tools available for estimating emissions. These tools and sources may include parameters that can be easily obtained (e.g. number of employees, number of vehicle miles travelled, etc.); emissions factors and engineering data; geographic information systems (GIS); and computer models (e.g. hydrology/water flow models).
For a cost-effective management scheme, you may wish to implement the next sub-element (Data Processing) or choose another element from the Management scheme elements list.
Relevant tools
- OECD: Scoping Study on the Inclusion of Releases and Transfers from Small and Medium-sized Enterprises (SMEs) in PRTRs (2008)
- UNITAR and IOMC: Designing the Key Features of a National PRTR System, UNITAR Guidance Series for Implementing a National PRTR Design Project, Supplement 2 (1997)
- UNITAR and IOMC: Guidance on Estimating Non-point Source Emissions, UNITAR Series of PRTR Technical Support Materials, No. 3 (1998)
- OECD: Resource Compendium of PRTR Release Estimation Techniques - Part 2: Summary of Diffuse Source Techniques (2003)
- OECD: Resource Compendium of PRTR Release Estimation Techniques, Part 4: Summary of Techniques for Releases from Products (2011) - Part 1
- OECD: Resource Compendium of PRTR Release Estimation Techniques, Part 4: Summary of Techniques for Releases from Products (2011) - Part 2