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Industry and control agencies have long expressed a need for consistency in the application of air quality models for regulatory purposes. This Utah Division of Air Quality (UDAQ) guideline document provides a common basis for estimating the air quality concentrations used in assessing control strategies and developing emission limits.
The continuing development of new air quality models and dispersion modeling techniques, in response to regulatory requirements and the expanded requirements for models to cover even more complex problems have emphasized the need for periodic review and update of this guidance document. Three on-going activities provide direct input to revisions of these guidelines. The first activity consists of UDAQ staff meetings conducted for the purpose of ensuring consistency and providing clarification in the application of models. The second activity, directed toward the improvement of modeling procedures, is the cooperative agreement that UDAQ has with the Environmental Protection Agency (EPA) and the scientific community. This agreement provides scientific assessment of procedures and proposed techniques, and sponsors workshops on key technical issues. The third activity is the solicitation and review of new models from the technical and user community. In the March 27, 1980 Federal Register, a procedure was outlined for the submittal to EPA of privately developed models. After extensive evaluation and scientific review, the models and modeling techniques are made available by EPA, for use in regulatory modeling analyses.
This document embodies revisions to the "Utah Division of Air Quality Modeling Guidelines." It is intended to be used in conjunction with the Notice of Intent Guide by sources seeking an Approval Order from the Utah Division of Air Quality. Although the text has been revised since its original publication, the present content and topics are similar. As necessary, new sections and topics are included. The UDAQ does not make changes to the guidance on a predetermined schedule, but rather on an 'as needed' basis. Changes in UDAQ modeling policy as a result of new regulatory actions or scientific data may not warrant immediate revision to this document. Therefore, this document shall remain in draft status. The UDAQ believes that revisions to this guideline should be responsive to user needs and should involve public participation to the greatest possible extent. Information on the current changes not reflected in this modeling guidance document may be obtained by e-mailing the UDAQ modeling staff.