"Hot Spots" Inventory Guidelines

This page last reviewed February 20, 2014

The AB 2588 Air Toxics "Hot Spots" Emission Inventory Criteria and Guidelines Regulation (Guidelines) provides direction and criteria to facilities on how to compile and submit air toxics emission data required by the "Hot Spots" Program.  On November 16, 2006, ARB staff presented to the Board proposals for amending the Guidelines to incorporate diesel PM into the "Hot Spots" Program. The Board approved the proposed amendments to the Guidelines with modifications.

Current Regulations (approved by OAL on August 27, 2007)

Regulation (CCR) (pdf - 42k)

Emission Inventory Criteria and Guidelines Report (Sections I-XI) (doc - 325k) (pdf - 325k)
Appendix A (List of Substances) (Excel - 178k) (A-I pdf - 115k) (A-II pdf - 64k) (A-III pdf - 55k) (Notes pdf - 64k)
Appendix BI (Reporting Formats) (doc - 104k) (pdf - 104k)
Appendix BII (Reporting Forms) (doc - 1,913k) (pdf - 1,913k)
Appendix C (Facility Responsibilities) (doc - 195k) (pdf - 195k)
Appendix D (Source Testing) (doc - 91k) (pdf - 91k)
Appendix E (Requirements for Smaller Facilities) (doc - 75k) (pdf - 75k)
Appendix F (Screening HRAs) (doc - 57k) (pdf - 57k)
Appendix G (Documents Incorporated by Reference) (doc - 55k) (pdf - 55k)

Formal Rulemaking Documents

The Emission Inventory Criteria and Guidelines are used for preparing emission inventory plans and reports to develop site-specific inventories of air emissions of toxic substances. The Guidelines do the following:  1) specify which facilities are subject to air toxics emission inventory reporting and update reporting; 2) specify information a facility operator must include in a facility's air toxics emission inventory plan and inventory report; 3) identify specific classes of facilities that emit less than ten tons per year of criteria pollutants that are subject to the Hot Spots program and specify their emission inventory reporting requirements; 4) specify source testing requirements, acceptable emission estimation methods, and the reporting formats to be used; 5) establish groups of the substances to be inventoried; 6) designate facilities into levels for purposes of update reporting, based on prioritization scores, risk assessment results, or de minimis thresholds; 7) exempt "low level" facilities from further update reporting unless specified reinstatement criteria are met, and specify the update reporting requirements for other facilities; 8) specify information a facility operator must include in a facility's update to the facility emission inventory; and 9) include provisions for integrating Hot Spots reporting with other district programs if specified criteria are met.

The Guidelines are organized into sections which address related requirements.  Sections are included on applicability, facility removal from the program, update categories, reporting requirements, and source testing requirements.

The appendices to the Guidelines are useful documents which may be downloaded separately from the Guidelines Report. Appendix A includes three lists of substances in the program: those for which emissions must be quantified; those for which production, use, or other processes must be reported; and those which need not be reported unless manufactured by the facility. Appendix B contains reporting formats and instructions.  Appendix C is the Facility Guideline Index which specifies responsibilities for specific facility classes. Appendix D indicates source testing requirements.   Appendix E specifies requirements for classes of facilities emitting less than 10 tons per year of criteria pollutants.  Appendix F contains the criteria for inputs for risk assessment using screening air dispersion modeling. Appendix G is the list of documents which have been incorporated into the Guidelines by reference.

Link to previous drafts of Guidelines Regulation

Frequently Asked Questions (FAQs) (doc) (pdf) (as of 9/07)
DRAFT - Screening Risk Assessment Tables for Diesel Engines

ARB's Emission Factor Certification Database
1989 Technical Guidance Document for EI Guidelines (PDF - 8MB!)
  Addendum to TGD for wood fired boilers
More Information about Appendix A - List of Substances

Information for local air district staff only:
Clearinghouse of diesel engine emissions data