Air Quality Modeling Guidance for Permits
This webpage presents current air quality permit modeling guidance for estimating impacts from stationary sources of air pollution.
For general permitting questions, contact the Stationary Sources Program. Contact monitoring or modeling staff in the Technical Services Program for monitoring or modeling questions, respectively.
NEW: Completeness Checklist for Modeling Submittals
NEW: FAQs on Air Quality Modeling Data and Techniques
Colorado Modeling Guideline for Air Quality Permits
Many of the Division's modeling guidance documents on this site were revised in late December 2005 to update regulatory citations because of changes to Colorado AQCC Regulation No. 3 and Appendix W to 40 CFR Part 51.
- guide.pdf (Dec. 27, 2005; Tables 2, 3, 5, 7, 8 last updated May 20, 2011; threshold analysis) - This is Colorado's primary permit modeling guideline. It is intended to be used along with applicable
federal guidance. The guideline was revised in December 2005 to reflect revisions to
Colorado AQCC Regulation No. 3 (pdf) and Appendix W to 40 CFR Part 51 -
Guideline on Air Quality Models (pdf). Here is a side-by-side comparison with the previous version:
Guide-12_comparison_to_Guide-11_oldversion.pdf (6,440 K)
- The federal rule adopting
AERMOD became effective December 9, 2005. As of December 9, 2006, the new model--AERMOD--should be used for appropriate application as a replacement for ISC3. (see Federal Register Volume 70, Number 216
Email attachments: Please verify that emails with attachments are received by the Division. Emails with ZIP, executable, and some other types of attachments are automatically rejected by the state's email system.
Supplemental Modeling Guidance, Forms, and Information
- Air Quality Modeling Form -
AQImpactForm1.pdf (118 k) (March 8, 2002) This optional form is a supplement to the
Pollution Emission Notice (APEN) and application forms. If the optional modeling form is filed with the Division, it will help permit reviewers determine if modeling is warranted. If modeling is warranted, the data on the form may be used in the modeling process.
- Checklist for Non-PSD Sources/Modifications (e.g., minor sources) -
MinorSourceImpactChecklist.pdf (333 k) (March 8, 2002; updated 4/25/11) Permit applicants for sources not subject to the major PSD rules (e.g., new minor sources, minor modifications) may use this optional checklist to help determine if the permit application has all of the information necessary for the Division to complete the air quality impact analysis required by the regulations. Many of the items in this checklist are discussed in section 7 (page 45) of the
Colorado Modeling Guideline. It applies to sources emitting particulates, carbon monoxide, lead, sulfur dioxide, and nitrogen oxides. Sources emitting only volatile organic compounds (VOCs) may disregard this checklist.
- Background concentration form - AmbientBackgroundConcentrationExcelMacroForm.xlsm (13k) (April 17, 2012)
- Third Party Modeling Review (SB11 – 235) request procedure – Third_Party_Modeling_Review_Procedure_Option.pdf (192 k) This option may be available for minor source permitting actions if a modeling review backlog exists.
- Checklist for Modeling Protocol -
protocol.pdf (42k) (June 17, 1997)
- Database of "scenic and/or important views" -
scenicvw2005.pdf (88k) (March 11, 2005) Database of the Class II sensitive views for major source PSD permits. This database is used by the Division to determine if there are any sensitive Class II views that might trigger the visibility "additional impact analysis" requirements under the PSD rules.
- Prevention of Significant Deterioration (PSD) Increment Tracking -
psdtrac.pdf (154 k) (February 26, 2001; updated 12/28/05) Explains how PSD increments and increment consuming/expanding emissions are currently tracked in Colorado; provides guidance for selecting increment consuming/expanding sources for major source PSD increment modeling.
- Maps, Figures, Tables
Meteorological & Geophysical Data for Air Quality Permit Modeling
The Technical Services Program of the
Air Pollution Control Division has data from current and historic meteorological towers in Colorado that are suitable for use in regulatory models. Contact the Division for data. Division approval should be obtained on a case-by-case basis before meteorological datasets are used for regulatory (e.g., air permit) modeling.
Maps, Class I Receptors, Figures, Tables for Air Quality Permit Modeling
The following list provides various maps, figures, and tables that might be useful during the permitting process. Some of these items are copied from Colorado permit modeling guidance documents. Others are unique to this page.
- U.S. EPA
- Support Center for Regulatory Atmospheric Modeling
(SCRAM) - EPA guidance, models, user's guides, and related information. The primary EPA modeling guideline is Appendix W to 40 CFR Part 51
- Technology Transfer Network
(TTNWeb)- a collection of related Web sites containing information about many areas of air pollution science, technology, regulation, measurement, and prevention.
- New Source Review (NSR)
- OAQPS Air Quality Modeling - topics and areas associated with air quality modeling.
- Atmospheric Sciences Modeling Division (ASMD) - the Division is part of NOAA's Air Resources Laboratory and is responsible for performing much of the air pollution meteorology research for the USEPA.
- Federal Land Managers