Source Attribution

The Online Resource Center contains the current versions of documents, methodologies and tools necessary to begin implementing AB 617 Community Air Monitoring Plans and Community Emission Reduction Programs. The Online Resource Center and the Final Draft Community Air Protection Blueprint establish program requirements and provide resources for program implementation. Comments on the Draft Blueprint and Resource Center can be found in the viewable record.

Statute requires CARB to identify methodologies for assessing, identifying and estimating the relative contribution of sources or categories of sources. To meet this requirement, CARB has identified a suite of source apportionment methodologies, each with different data and staff resource requirements that affect the time and resources necessary to complete.

The results of source apportionment will inform development of emission reduction strategies contained within the community emissions reduction programs. It is recommended that the selected source apportionment approaches and results be reviewed in an open, public process in conjunction with the community and/or steering committee to ensure that the most applicable methodologies are used and that the data is representative of the community. This public process will serve to:

Consider the representativeness of available data and whether it is necessary to pursue new analyses or input data collection (i.e., are currently available results adequate to inform strategy development?).
Avoid missing major emission source contributors.
Avoid mischaracterizing emission source activities or operations.
Minimize over- or under-apportioning pollution burdens to sources within or outside the community.

For further information relating to Source Attribution, please refer to the AB 617 Recommended Source Attribution Technical Approaches.