Skip to main content

Emissions Reporting

Emissions Inventory Reporting for Stationary Sources


District Rule 4.8 Further Information and other rules require that permitted facilities report annual throughput data to the District.  Throughput data is due by the last day of February each year for the following calendar year usage.  The blank throughput form is mailed to responsible officials with the facility permit package in December each year.

The District prepares criteria air pollutant and toxic emissions inventories for permitted stationary sources based on the throughput information reported and District engineering evaluations.  This work is funded under the AB 197 grant from the Air Resources Board and is not currently billed to stationary sources on the annual permit invoice. 

The District submits emission inventory updates for criteria and toxics air pollutants to the Air Resources Board each year.  The ARB provides some of this information on their website for some facilities.  The remaining facilities and data may be found on this website:


Information on CTR and the Amended CTR

The Air Resources Board adopted the Criteria and Toxics Emissions Report Regulation or CTR in 2018.  The CTR Regulation required annual criteria and toxics emissions reporting for stationary sources subject to the Mandatory Reporting Regulation for GHGs, or those that had nonattinment criteria pollutant emissions over 250 tons per year, or that were prioritized as "high" under the AB 2588 program.  The District has utilized the existing facility throughputs, AB 2588 prioritizations, and engineering evaluations to calculate emissions for facilities initially subject to CTR.   There are approximately 60 facilities subject to CTR in the District that reported annual criteria and toxic emissions inventories under the first CTR regulation.

The ARB amended CTR in 2020 to expand the applicability to a large number of additional, small facilities.  Under the amended CTR most facilities in the District will be required to report annual criteria and toxic emissions.

Beginning with data year 2024,  Additional Applicability Facilities will become subject to emissions reporting requirements. The District does not have staffing resources to prepare enhanced emissions reports for all facilities subject to the Additional Applicability in CTR.   The District has requested tools from ARB to make the reporting process less resource intensive but they have not yet been provided. 

While it will not be requested by the District, information submitted to the District in response to CTR will be forwarded to the ARB.

For information on CTR requirements and available guidance documents, please visit CARB’s websites:

CTR Webpage:

CTR Regulation: 02/Unofficial%20CTR_Jan2022_0.pdf

CTR Guidance Documents: