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Conference on Air Quality Modeling

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Environmental Protection Agency (EPA).


Notice of conference.


We announce the Eighth Conference on Air Quality Modeling. Such a conference is required by section three hundred twenty of the Clean Air Act (CAA) to be held every three years. The purposes of the Eighth Conference are to provide an overview of the latest features of the new air quality models and to provide a forum for public review and comment on potential revisions to the way the Agency determines and applies the appropriate air quality models in the future.


The eighth conference will be held on September 22, 2005 from 9 a.m. to 5:30 p.m. and on September 23, 2005 from 8:30 a.m. to 5 p.m. Requests to speak at the conference should be submitted to the individual listed below by September 9, 2005. All written comments must be submitted by close of business October 24, 2005.


Conference: The conference will be held in the EPA Auditorium, Room C111, 109 T.W. Alexander Drive, Research Triangle Park, NC.

Comments: Submit your comments, identified by Docket ID No. OAR-2005-0157 by one of the following methods: Federal eRulemaking Portal: Follow the on-line instructions for submitting comments. Agency Web site:​edocket. EDOCKET, EPA's electronic public docket and comment system, is EPA's preferred method for receiving comments. Follow the on-line instructions for submitting comments. E-mail:​edocket. Fax: 202-566-1741. Mail: OAR Docket, Environmental Protection Agency, Mailcode: B102, 1200 Pennsylvania Ave., NW., Washington, DC 20460. Please include a total of 2 copies. Hand Delivery: EPA/DC, EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information. Instructions: Direct your comments to Docket ID No. OAR-2005-0157. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at​edocket, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through EDOCKET,, or e-mail. The EPA EDOCKET and the Federal Web sites are “anonymous access” systems, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through EDOCKET or, your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about EPA's public docket visit EDOCKET on-line or see the Federal Register of May 31, 2002 (67 FR 38102). For additional instructions on submitting comments, go to unit II of the SUPPLEMENTARY INFORMATION section of this document. Docket: All documents in the docket are listed in the EDOCKET index at​edocket. Although listed in the index, some information is not publicly available, i.e., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in EDOCKET or in hard copy at the OAR Docket, EPA/DC, EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the OAR Docket is (202) 566-1742.

Background information: Additional information and a more detailed agenda are electronically available at​scram001/​8thmodconf.htm.

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Warren Peters, U.S. Environmental Protection Agency, Mail Drop D243-01, T.W. Alexander Drive, Research Triangle Park, NC 27709; telephone: (919) 541-5337; e-mail address:

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The Guideline on Air Quality Models (hereafter, called the Guideline, which is found in Appendix W to 40 CFR part 51), is used by EPA, States, and industry to prepare and review new source permits and State Implementation Plan revisions. The Guideline serves as a means by which consistency is maintained in air quality analyses. We originally published the Guideline in April 1978 and it was incorporated by reference in the regulations for the Prevention of Significant Deterioration (PSD) of Air Quality in June 1978. We revised the Guideline in 1986, and updated it with supplement A in 1987, supplement B in July 1993, and supplement C in August 1995. We published the Guideline as appendix W to 40 CFR part 51 when we issued supplement B. We republished the Guideline in August 1996 (61 FR 41838) to adopt the CFR system for labeling paragraphs.

To support the process of developing and revising the Guideline during the period 1977-1988, we held the First, Second and Third Conferences on Air Quality Modeling as required by Section 320 of the Clean Air Act to help standardize modeling procedures. These modeling conferences provided us with comments on the Guideline and associated revisions, thereby helping us introduce improved modeling techniques into the regulatory process. Start Printed Page 48950

In October 1988, we held the Fourth Conference on Air Quality Modeling. Its purpose was to advise the public on new modeling techniques and to solicit comments to guide our consideration of any rulemaking needed to further revise the Guideline. We held the Fifth Conference on Air Quality Modeling in March 1991, which served as a public hearing for the proposed revisions to the Guideline. In August 1995, we held the sixth conference as a forum to update our available modeling tools with state-of-the-science techniques for airing these issues and for the public to offer new ideas.

The last conference held was the Seventh Conference on Air Quality Modeling in June 28 and 29, 2000, which served as a public hearing for the proposed changes to the recommended air quality models in Appendix W. Several presentations were made, including the development of an enhanced Gaussian dispersion model with boundary layer parameterization (AERMOD [1] ); the development of the CALPUFF modeling system by Earth Tech, Inc. through the Interagency Workgroup on Air Quality Modeling (IWAQM [2] ); the development and testing of ISC-PRIME by the Electric Power Research Institute's building downwash program; and on revisions to the Emissions and Dispersion Modeling System (EDMS) by the Federal Aviation Administration. In addition, several presentations on models for consideration as “alternative models” were made and a panel of experts discussed meteorological data assimilation for the next generation of dispersion models. The proceedings are found in Docket No. A-99-05.

Public Participation

The Eighth Conference on Air Quality Modeling will be open to the public; no admission fee is charged and there is no formal registration. The conference will begin the first morning with introductory remarks by the presiding EPA official. The following topics will be presented:

I. AERMOD implementation issues;

II. CALPUFF implementation issues;

III. Assimilated meteorological data for air dispersion models;

IV. New approach for updating (revising) models;

V. Alternative approaches for selection of approved dispersion models; and,

VI. Other presentations by the public.

Those wishing to speak at the conference, whether to volunteer a presentation on a special topic or to offer general comment on any of the modeling techniques scheduled for presentation, should contact us at the address given in the FURTHER INFORMATION section (note the cutoff date). Such persons should identify the organization (if any) on whose behalf they are speaking and the length of presentation. If a presentation of general comments is projected to be longer than 10 minutes, the presenter should also state why a longer period is needed. Persons failing to submit a written notice but desiring to speak at the conference should notify the presiding officer immediately before the conference and they will be scheduled on a time-available basis.

The conference will be conducted informally and chaired by an EPA official. There will be no sworn testimony or cross examination. A verbatim transcript of the conference proceedings will be produced and placed in the docket. Speakers should bring extra copies of their presentation for inclusion in the docket and for the convenience of the reporter. Speakers will be permitted to enter into the record any additional written comments that are not presented orally. Additional written statements or comments should be sent to the OAR Regulatory Docket (see ADDRESSES section). A transcript of the proceedings and a copy of all written comments will be maintained in Docket OAR-2005-0157 which will remain open until October 24, 2005 for the purpose of receiving additional comments.

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Dated: August 17, 2005.

Mary E. Henigin,

Acting Director, Office of Air Quality Planning and Standards, Office of Air and Radiation.

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1.  A MS/E PA R egulatory MOD el; AERMOD is being developed by AERMIC: A MS/E PA R egulatory M odel I mprovement C ommittee.

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2.  IWAQM was formed in 1991 to provide a focus for development of technically sound regional air quality models for regulatory assessments of pollutant source impacts on federal Class I areas. IWAQM is an interagency collaboration that includes efforts by EPA, U.S. Forest Service, National Park Service, and Fish and Wildlife Service.

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[FR Doc. 05-16682 Filed 8-19-05; 8:45 am]