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Support Center for Regulatory Atmospheric Modeling (SCRAM)

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09/02/16 Please save the dates of November 14-17, 2016 for the 2016 EPA Regional, State, and Local Modelers' Workshop to be held at the US Customs House in New Orleans, LA. Tuesday, November 15, will be open to industry and outside participants in addition to the co-regulating agencies. A preliminary agenda is posted for travel planning purposes. A registration and workshop informational website will be available later in September.

08/18/16 A webinar regarding the Draft O3 and PM2.5 SILs Guidance for PSD Program will be conducted on Wednesday, August 24, 2016 from 2:00p to 3:30p EDT.

08/04/16 The draft SO2 Modeling Technical Assistance Document has been updated to clarify receptor placement and the minimum number of years to model.

08/01/16 A Model Clearinghouse concurrence memorandum to Region 6 regarding the use of the beta ARM2 technique as an alternative model has been added to the MCHISRS database.

08/01/16 A Model Clearinghouse concurrence memorandum to Region 8 regarding the use of the ADJ_U* beta option in AERMET as an alternative model has been added to the MCHISRS database.

08/01/16 The Draft Guidance on SILs for Ozone and PM2.5 in PSD has been posted on the NSR Permitting website along with supporting documentation. The EPA will accept public comment on the draft guidance package through Septemebr 30, 2016.

07/26/16 Updated regulatory versions of CALPUFF and CALMET (version 5.8.5, dated 151214) are now available. The links to the updated CALPUFF Modeling System files, the associated Model Change Bulletin (MCB-H) can be found on the CALPUFF webpage.

03/30/16 A coding bug has been discovered with AERSCREEN (v15181) in certain circumstances involving the use of the inversion and/or shoreline fumigation option. A temporary and simple workaround is described in this email message and will be resolved in the next release of AERSCREEN later this spring.

12/10/15 A Clarification on the Approval Process for Regulatory Application of the AERMOD Modeling System Beta Options memorandum is now available. This memo discusses the appropriate process for the approval of the AERMOD Modeling System with the use of various beta options for regulatory applications.

09/14/15 The presentations, transcripts, and audio recordings from the 11th Conference on Air Quality Modeling are now available. Additionally, all of the model code, technical support documentation, draft guidance, IWAQM reports, supporting docket material, etc. related to the proposed Guideline on Air Quality Models rulemaking are accessible through the 11th Conference on Air Quality Modeling informational website.

07/14/15 A proposal to revise the Guideline on Air Quality Models was signed by the Administrator on July 14, 2015. The rulemaking Proposal and Fact Sheet for this proposed rulemaking package are availablce through the 11th Conference on Air Quality Models informational website.

12/04/14 The Draft Modeling Guidance for Demonstrating Attainment of Air Quality Goals for Ozone, PM2s, and Regional Haze is now available for consideration, review, and comment. This document is a revision to the previous modeling guidance which was released in April 2007.

04/08/14 Interim guidance for the treatment of condensable particulate matter test results in the PSD and NSR permitting programs is now available.

01/14/14 The draft SO2 Monitoring and Modeling Technical Assistance Documents have been updated based on public comments and are available on the Sulfur Dioxide Implementation web page.

08/26/13 The NO2/NOx In-Stack Ratio (ISR) Database has been updated based on the first database submission from the State of Oklahoma and the second database submission from the State of Alaska.


This website is maintained by EPA's Air Quality Modeling Group (AQMG). The AQMG conducts modeling analyses to support policy and regulatory decisions in the Office of Air and Radiation (OAR) and provides leadership and direction on the full range of air quality models and other mathematical simulation techniques used in assessing control strategies and source impacts. Documentation and guidance for these air quality models can be found on this website, including downloadable computer code, input data, and model processors.

You will need Adobe Acrobat Reader to view the Adobe PDF files on this site. See EPA's PDF page for more information about getting and using the free Acrobat Reader.

This site contains the following sections.

Air Quality Models - Provides descriptions and documentation for three types of air quality models: dispersion, photochemical, and receptor models. Also provided with the dispersion modeling section are source code and associated user's guides and documentation for preferred/recommended models, screening models, and alternative models.

Modeling Applications and Tools - Provides more detailed information on modeling analyses AQMG has conducted to support policy and regulatory decisions in OAR including assessment of control strategies and source culpability. In addition, this site provides access to EPA developed tools for use in State Implementation Plan (SIP) demonstrations and other air quality modeling assessments.

Modeling Guidance & Support - Provides current guidance for applying air quality models for regulatory applications for both State Implementation Plans (SIP) demonstrations and revisions, as well as permit applications for new source reviews including Prevention of Significant Deterioration (PSD) regulations.  Included is the Model Clearinghouse which is designed to help record the interpretation of modeling guidance for specific regulatory applications.  Also included in this area are links to modeling contacts within the EPA Regional Offices and State environmental agencies. 

Meteorological Data & Processors  - Provides information on Meteorological data used in air quality models as derived from both ambient measurements and meteorological models. Processors based on these two main sources of meteorological data are also provided.

Conferences & Workshops - Provides announcements and related information for upcoming meetings, conferences, and workshops including agendas, review materials, and links.

Reports & Journal Articles
- Provides access to reports developed by AQMG staff as well as a bibliographic listing of journal articles they have authored or co-authored.

Related Links --- Provides website links of interest to air quality modelers and policy analysts.

Employment Opportunities:  AQMG currently has no open positions to fill. As positions become open, AQMG will update this website with details. In addition, job announcements can be found on the internet at the Office of Personnel Management website. The easiest way to find the announcement is to look for openings located in Research Triangle Park, North Carolina.

If you would like to be notified when we have a position for which you may be interested in applying, you may send a resume to Tyler Fox, Group Leader at: Fox.Tyler@epa.gov.


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