Appendix W Refresher

Tyler Fox

9th Conference on Air Quality Modelin

October 9, 2008
Newsflash

• Promulgation of AERMOD Modeling 

System in November 2005

– Federal Register notice published Dec 

2005

• As of December 9, 2006, AERMOD 

promulgated as a replacement to ISaccordance with Appendix W. 

– See SCRAM for more information at: 

http://www.epa.gov/scram001/dispersirec.htm
Outline

• Reflect back on . . .

– 8th Modeling Conference

• Vision and Essential Elements

– RO call for improved support

• AERMOD Development & Maintenance• CALPUFF Model Update Protocol• R/S/L Workshops• Modeling Clearinghouse• Clarification Memos (Roger Brode)• Importance of Process
Dispersion Modeling Futur

Vision Statement

“Lead and promote collaborative effo

on near-field air quality modeling to improve source culpability assessments”
First Essential Element

Foster a collaborative environment aimed at strengthening our technicexpertise and working relationships across EPA, other Federal agencieand the scientific community to regour leadership role and promote usbest science and evaluation metho
Fourth Essential Elemen

Promote a community approach to model development and acceptancthat champions the use of best sciesupports continual improvement in modeling science and data, and timmodel acceptance for use in regulaarena.
Need for Improved Modeling Sup

• In May 2006, the ROs presented two 

recommendations to the Air Division Directors:

– OAQPS needs to enhance its technica

expertise regarding the “new generationear-field models

– OAQPS needs to accelerate its reinsta

of an active and effective Model Clearinghouse to provide technical expfor permitting and SIP applications

• OAQPS has responded and taken a
AERMOD Modeling System

Development and Maintenanc

• AERMOD Implementation Workgroup

– Built upon initial AERMOD Implementation Group – April 20

2006 (See A. Cimorelli presentation at 8th Modeling Conf)

– Inaugural AIWG Conference Call in January 2007 with Roge

Randy Robinson as co-chairs

– Composed of State, Local, EPA Regions, EPA HQ with 3 St

subgroups on MET issues, surface characteristics, and urbaimprovements.

– Collaborative and inclusive process that relies on the experi

knowledge of model users in the states and regions to advison implementation issues and priorities for resources.

• Re-instituted AERMIC to guide OAQPS on s

issues

– AMS/EPA Regulatory Model Improvement Committee 

formed in 1991; charged to develop replacement for ISbased on state-of-the-science; AERMOD promulgated 2006
• New AERMIC committee met in RTP durin

2008 and July, 2008

• Membership of “new” AERMIC committee:

• Roger Brode, OAQPS, Co-chair• Jeff Weil, CIRES-NCAR, Co-chair• Akula Venkatram, UC-Riverside• Al Cimorelli, EPA Region 3• Bret Anderson, EPA Region 7• Vlad Isakov, EPA/ORD/AMD

New AERMIC
CALPUFF Update Proce

• Incumbent upon EPA to perform an 

independent assessment of CALPUwhen updating to new versions

• CALPUFF requires extensive asses

and understanding of changes madeapprovals made by EPA, not develo

• CALPUFF Update Tool – Introduced 

Modeling Conference in Sept 2005
CALPUFF Update Too

• Compares 2 CALPUFF versions; propose

(beta) vs. current version (base)

• Determines differences in results across 

scenarios, including a range of domains, inputs and sources

• Provides a standardized methodology for 

assessing consequences from changes icodes

• EPA has successfully applied as part of u

– Version 5.7 to 5.711a (Dec 2005)– Version 5.711a to 5.8 (June 2007)
Role of R/S/L Workshops

• Appendix W includes the following references to 

regional workshops:

– “Historically, three primary activities have provided dire

revisions of the Guideline. The first is a series of annu

workshops conducted for the purpose of ensuring coand providing clarification in the application of mode

[Preface, paragraph (b)]

– “From time to time situations arise requiring clarificati

intent of the guidance on a specific topic. Periodic ware held with the headquarters, Regional Office, Stateagency modeling representatives to ensure consiste

modeling guidance and to promote the use of more acquality models and data bases. The workshops serve further explanations of Guideline requirements to the ROffices and workshop reports are issued with this clarinformation.” [Paragraph 1.0(f)]

– “Two additional sources of modeling guidance are t

Clearinghouse and periodic Regional/State/Local Modworkshops.” [Paragraph 3.0(a)]
History of R/S/L Workshop

• EPA’s 2008 Regional/State/Local Modele

Workshop was held on June 10-12, 2008 Denver, CO

• This was the 30th R/S/L Workshop, begin

with 1978 but skipping one year

• Attendance was limited to OAQPS & Reg

Modeling Contacts in the beginning, but nincludes State & local agencies

• 2008 attendance was about 90 total, inclu

all 10 EPA Regional Offices, 29 States, 5 agencies, and 5 FLMs

• Presentations since 2005 are available fr

SCRAM at:

– http://www.epa.gov/scram001/conferenceind
Model Clearinghouse

• What is it? 

– A process and mechanism by which an EPA R

Office can obtain EPA Headquarters concurreimplementation issues related to air quality mo

• Statutory authority?

– Appendix W, Section 3.3(b): “As appropriate, 

Office may request assistance from the Model Clearinghouse after an initial evaluation and dhas been reached concerning the application omodel, analytical technique or data base in a pregulatory action.
Model Clearinghouse Goa

• Provides national consistency in regu

decisions

• Timely interpretation of guidance (as 

arise)

• Minimizes bad precedents:

– Get in early on issues– Memoranda provide essential support to 

regions, states and locals

• Guidance development through cons

building
MC Operation

• Technical issues

– Response provided by OAQPS/AQMG 

other technical experts with review by pstaff

• Policy issues (if submitted to MC)

– Referred to New Source Review Group– Response provided by OAQPS/Air Qua

Policy Division (Bill Harnett, DD) with teinputs as appropriate

• As appropriate, MC responses may b

reviewed by OGC
Formal Clearinghouse Proc

• State contacts Region• Region writes memo to clearinghouse: 

– Statement of Issue– Desired approach– Justification

• Clearinghouse facilitates solutions and writes fo

response

• Clearinghouse summarizes & archives decisions

– Searchable database (MCHISRS) via web access (SC– Present summary at annual Regional/State/Local work– Write annual report

• OAQPS develops guidance as appropriate: 

– Policy memo, EPA Report, Rule Making
Model Clearinghouse Informat

Storage and Retrieval System (MC

• Old MCHISRS system

– Only searchable by those who have an “epa.g

address

– Formal memos and MCHISRS records are sep

SCRAM

• New MCHISRS system (as of 5/10/07)

– Allows full public access so restriction to “epa.

eliminated

– Links MCHISRS records to the formal MC mem– Searchable by topic, pollutant, RO, fiscal year

etc.

– http://www.epa.gov/scram001/guidance_

clearinghouse.htm


Importance of Process

• Importance of Model Clearinghouse proces

been stressed recently, especially with promulgation of CALPUFF and AERMOD

– Emphasis on formal process of Regional Office pre

issue to Model Clearinghouse, perhaps initiated at with full background information and RO position

– Informal contacts with OAQPS staff do not constitu

“consulting with the Model Clearinghouse”

• Importance of “Modeling Protocols” to get 

and input early in the process (EPA & FLM

• Respecting the roles of various parties/sta

– Applicant– Reviewing authority (RO or State)– OAQPS as needed, with both technical (AQMG) an

(AQPD) perspectives

– Public
Importance of Process

• Importance of consistency is stressed sev

places in Appendix W, including the very fsentence: 

– “Industry and control agencies have long expressed a n

consistency in the application of air quality models for repurposes.”

• Clarify distinction between regulatory modelin

applications, which fall under purview of Appe

and non-regulatory applications, such as risk assessments

– “The Guideline recommends air quality modeling techni

should be applied to State Implementation Plan (SIP) reexisting sources and to new source reviews (NSR), inclprevention of significant deterioration (PSD). Applicable criteria air pollutants, it is intended for use by EPA Regiin judging the adequacy of modeling analyses performeState and local agencies and by industry.”