7th Modeling Conference

  The 7th Conference on Air Quality Modeling  was held on June 28-29, 2000 in Washington,  D.C.  The main purpose of the Conference was to receive comments on EPA's proposal to add several new modeling techniques to Appendix W of 40 CFR Part 51. The conference was announced in the Federal Register on May 19, 2000 (Volume 65, Number 98) and proceedings can be viewed HERE or from the file list below. 

  Based on public comments from the 7th Conference, the Guideline on Air Quality Models (Appendix W to 40CFR Part 51) was substantially revised and may be seen HERE.  The public comments clearly supported many proposed changes, notably:
   --  adoption of CALPUFF in appendix A, as proposed, for assessing long range
       transport of pollutants and their impacts on Federal Class I areas;
   --  removal of Climatological Dispersion Model (CDM), Ram and the Urban Airshed
       Model (UAM) from appendix A, as proposed;
   --  simplification of complex terrain screening techniques in section 5;
   --  revision of section 9 to reflect our October 1997 settlement with the Utility Air
       Regulatory Group regarding specification of emissions from background sources,
       as proposed;
   --  transfer of appendix B and appendix C to our website, as proposed.

  Regarding AERMOD, nearly every commenter urged EPA to integrate aerodynamic downwash into AERMOD (i.e., not to require ISC-PRIME for some analyses and AERMOD for others).  The only cautions were associated with the need for documentations, evaluation and review of the downwash enhancement to AERMOD. As a result of AERMIC's (the American Meteorological Society (AMS)/ EPA Regulatory Model Improvement Committee) efforts to revise AERMOD, incorporating the PRIME algorithm and making a few other incidental modifications and to respond to the public's cautions, we believe that AERMOD, as modified for downwash, merits further examination of performance results.  Also, since the April 2000 proposal, the Federal Aviation Administration decided to configure EDMS3.1 to incorporate the AERMOD dispersion model, and results of its performance with AERMOD only recently became available.  Consequently, AERMOD and EDMS4.0, as well as other conforming changes for the Guideline, will be the subject of a separate, later regulatory action.

Description   

PRIME (Plume RIse Model Enhancements)is a set of algorithms being evaluated as the next generation building downwash model.  This set of algorithms has been incorporated into the latest version of the Industrial Source Complex Short Term Model (ISCST3) and the revised test bed model has been named ISC-PRIME.  Various documents, source code, executable and testcase files are available below for download and evaluation.  These documents, code, etc. have been placed here for historical and comparison purposes since it is expected to be replaced with AERMOD (w/PRIME).

  PRMRPT              8/24/98       EPA Staff Report on ISC-PRIME. (903K)
  ISCPRMSR          8/26/04       ISC-PRIME and BPIPPRM source codes. (217K,ZIP)
  PRMTESTS         8/26/04       Executables, met data, test cases for ISC-PRIME and
                                                   BPIPPRM.  (639K,ZIP)
  PRIMPLDN         10/25/99      Draft: Development and Evaluation of the PRIME Plume
                                               Rise and Building Downwash Model (published in
                                               the March 2000 issue of JAWMA 50:  378 - 390). 
                                              This document serves as a benchmark that
                                              demonstrates the performance of this
                                              algorithm as implemented in ISC3.
                                              (If difficulty is encountered in printing pages  containing
                                              equations the use of a PostScript driver is suggested.)

Description

A committee, the AERMIC(American Meteorological Society/Environmental Protection Agency Regulatory Model Improvement Committee), was formed to introduce state-of-the-art modeling concepts into the EPA's air quality models.  The AERMIC's focus is on a new platform for regulatory steady-state plume modeling. This platform  includes: 1) air turbulence structure, scaling and concepts;  2) treatment of both surface and elevated sources;  and,  3) simple and complex terrain, and 4) AERMOD with the PRIME downwash algorithm. The modeling system has 3 components: AERMOD - the air dispersion model; AERMET - the meteorological data preprocessor; and AERMAP - the terrain data preprocessor.
 

Background

User's Guides  (Original Proposed Version)

Code and Utilities  (Original Proposed Version)

AERMOD Beta Test  -  version 02222 with PRIME

AERMET Beta Test  -  version 02222 (for PRIME)

AERMAP Beta Test  -  version 03107

Evaluation Databases for AERMOD version 02222

Description

Additional information is being provided in the form of two documents relevant to the revisions of the Guideline on Air Quality Models.  The revisions would enhance the Guideline by incorporating a new, general purpose dispersion model called AMS/EPA Regulatory MODel (AERMOD) to replace the existing Industrial Source Complex (ISC3) model in many air quality assessments and incorporate a new downwash algorithm - PRIME. The two documents offered below, including the Federal Register Notice, provide information on the performance of AERMOD when the model is modified in a manner suggested by public comment.