# Status and Role of EPA’s Model Clearinghouse 11 th 

### Conference on Air Quality Modeling RTP, NC George M. Bridgers OAQPS -AQAD -Air Quality Modeling Group 08/12/2015 1 U.S. Environmental Protection Agency

# Regulatory Requirements • Authority to modify a specified model in Appendix W or use a substitution must be granted through writing from the Administrator.

– 40 CFR Part 51 – Section 51.166: ( l) Air quality models. The plan shall provide for procedures which specify that— • ( 1) All applications of air quality modeling involved in this subpart shall be based on the applicable models, data bases, and other requirements specified in appendix W of this part ( Guideline on Air Quality Models). • (2 ) Where an air quality model specified in appendix W of this part ( Guideline on Air Quality Models) is inappropriate, the model may be modified or another model substituted. Such a modification or substitution of a model may be made on a case - by- case basis or, where appropriate, on a generic basis for a specific State program. Written approval of the Administrator must be obtained for any modification or substitution. In addition, use of a modified or substituted model must be subject to notice and opportunity for public comment under procedures set forth in § 51.102 . 2 U.S. Environmental Protection Agency 08/12/2015

# Regulatory Requirements (Cont.) • The regulatory authority for the approval of alternative model and techniques is delegated to the Regional Administrators through Section 3 of Appendix W.

– Delegated authority is further clarified in the proposed revisions to the Guideline. • However, Regional Offices still must seek concurrence from EPA Headquarters on any action that could be inconsistently applied across the other Regions ( ensuring national consistency ).

– 40 CFR Part 56 – Section 56.5: ( b) A responsible official in a Regional Office shall seek concurrence from the appropriate EPA Headquarters office on any interpretation of the Act, or rule, regulation, or program directive when such interpretation may result in inconsistent application among the Regional Offices of the act or rule, regulation, or program directive. 3 U.S. Environmental Protection Agency 08/12/2015

# Proposed Revisions to the Guideline • Importance of consistency is stressed several places in the Guideline on Air Quality Models (the Guideline or Appendix W) , including the very first sentence:

– “Industry and control agencies have long expressed a need for consistency in the application of air quality models for regulatory purposes .” 

### • In 1988, the Model Clearinghouse Operational Plan was developed and shared with the Regional Offices.

– Consistent with the regulations and the proposed revisions to the Guideline.

– http:// www.epa.gov/ttn/scram/11thmodconf/1988MCHOperationalPlan.pdf 4 U.S. Environmental Protection Agency 08/12/2015

# Proposed Revisions to the Guideline (Cont .) • The 1993 revision of the Guideline to add Supplement B included the first regulatory references to the Model Clearinghouse.

– Section 3.3.1 of the 1993 Guideline referenced to the Operation Plan.

– Included the first of three primary functions as, “Review of decisions proposed by EPA Regional Offices on the use of modeling techniques and data bases .” 

### • Subsequent revisions of the Guideline expanded the discussion of the Model Clearinghouse but also lost some of the clarity of the formal process that was being consistently followed within the EPA . 5 U.S. Environmental Protection Agency 08/12/2015

# Proposed Revisions to the Guideline (Cont .) • EPA’s OAQPS -AQAD -AQMG and Model Clearinghouse are responsible for the development and proposal of all preferred models or techniques per Appendix W, Section 3.1.
• To ensure national consistency and to respect the responsibilities mentioned above, it is appropriate that concurrence with the Model Clearinghouse is sought on the approval of any alternative model or technique per Appendix W, Section 3.2. 6 U.S. Environmental Protection Agency 08/12/2015

# Proposed Revisions to the Guideline (Cont .) • In the proposed revisions to the Guideline, the EPA proposes to codify the long - standing process of the Regional Offices consulting and coordinating with the Model Clearinghouse on all approvals of alternative models and techniques .

– Referencing the 1988 Model Clearinghouse Operational Plan.

– Referencing 40 CFR 51.166(l)(2) with an understanding of 40 CFR 56.5(b).

– Providing as much transparency to the internal process between the Regional Offices and the Model Clearinghouse that has existed for over 25 years.

– Allowing broad communication across stakeholder community so case -specific decisions are well - understood and applicable elsewhere. 7 U.S. Environmental Protection Agency 08/12/2015

# Formal Model Clearinghouse Process • State contacts Region Office with a regulatory modeling situation that requires EPA review and/or approval. • Regional Office determines if it is an alternative modeling situation per Appendix W, Section 3.2. • Regional Office writes request memorandum to the Modeling Clearinghouse :

– Statement of i ssue.

– Desired approach by the state/local/tribe or applicant.

– Justification per the requirements of Section 3.2.2. 

### • Clearinghouse is engaged and consulted on solutions and writes formal concurrence response memorandum. 8 U.S. Environmental Protection Agency 08/12/2015

# Formal Model Clearinghouse Process (Cont.) • Clearinghouse summarizes and archives decisions:

– Searchable database (MCHISRS) via web access (SCRAM). http://cfpub.epa.gov/oarweb/MCHISRS/

– Presents summary at annual Regional/State/Local Workshop and Modeling Conferences. 

### • OAQPS develops guidance or proposes updates to the Guideline on Air Quality Models, as appropriate:

– Policy memo, EPA report or guidance document, rulemaking.

9 U.S. Environmental Protection Agency 08/12/2015

# EPA’s Model Clearinghouse • http://www.epa.gov/ttn/scram/guidance_clearinghouse.htm
• Director of Model Clearinghouse:

– George Bridgers

– OAQPS/AQAD/AQMG

– bridgers.george@epa.gov

– (919) 541 - 5563
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