Guidance for small businesses


Submitting an environmental justice summary, modeling requirements determination (APCD-Form 114), and APEN


Getting started

We recommend completing the steps below in the following order:

  1. Calculate your emissions to determine whether you are APEN and/or permit exempt.
  2. Begin filling out the APEN form.
    • You will use this information to complete the EJ Summary and Form 114 (if applicable to your source).
  3. Complete the EJ Summary and Form 114. Submit both at the same time to the appropriate email addresses. These forms are generally processed within 5-10 business days.
  4. Complete the APEN form. Wait to submit the APEN until you receive the following documentation from the Air Pollution Control Division to include with the APEN submission:
    • Letter of Concurrence for EJ Summary.
    • Form 114 Modeling Determination.


How to calculate your uncontrolled actual emissions


How to submit an environmental justice summary

Do I need to submit an EJ summary?

Almost all applicants must submit an Environmental Justice Summary prior to submitting their APEN permit application. Categories of permit applications that do not need to submit Environmental Justice Report(s) are:

  • Air Pollution Emission Notice (APEN) updates only;
  • APEN exempt sources;
  • Permit exempt sources;
  • Administrative Permit Amendments (including but not necessarily limited to name changes, changes in contact information, transfers of ownership, and typographical error corrections); and
  • Operating permit renewal applications (Title V) only if the source has already submitted an EJ summary with an operating permit renewal application in the last 5 years.

Additional information is provided in the submission guidance for EJ Summaries document on the department’s Environmental Justice Report Tool for Air Quality Regulation 3 web page.

Steps to submitting an EJ Summary:

  1. Go to the New Environmental Justice Report Tool for Air Quality Regulation 3 and open the EJ Report Tool. Create and download an EJ Report for each census block group where the facility is located. 
    • Click the upper-right icon (circled in the screenshot below), then “+Add Location” and select your location on the map, and “Next” to generate the EJ Report.
Screenshot of APCD's Environmental Justice Report Tool, with icon circled to generate a Regulation 3 EJ Report

  1. Review this complete list of questions related to your source. Then, complete the Environmental Justice Summary Supplemental Information form and submit the completed online form. 
    • Note: Use your EJ Report generated in Step 1 above to identify whether your facility is located in a Disproportionately Impacted Community.
  2. Generate the required aerial or satellite image of your facility. Additional details about how to do this are available on the New Environmental Justice Report Tool for Air Quality Regulation 3 web page.
  3. Submit the EJ Report generated in Step 1 and the aerial or satellite image generated in Step 3 above to cdphe_apcd_ejreports@state.co.us with “EJ Summary” and the facility name in the subject line. 
    • Note: There is no fee associated with the processing of EJ Summaries.
  4. Once you complete steps 1-4 above, wait to receive a Letter of Concurrence. The division generally sends this letter within 5-10 business days. 
  5. Submit the Letter of Concurrence, EJ Summary, and all supplemental information with your APEN.
    • Note: For sources applying for Title V permits, please note that all Title V forms, instructions, and guidance documents have been updated effective August 2023. For more information, please visit the Title V operating permits web page. We encourage all facilities – particularly those that will be reclassified as Title V facilities – to submit the required EJ Summary as soon as possible.

How to submit a modeling requirements determination (APCD-114 Form)

Do I need to submit a Modeling Requirements Determination Form (Form-114)?

APCD-114 Form is required for all new facility applications and modifications, unless:

  • The project is exempt from APEN reporting requirements.
  • The project is exempt from construction permitting requirements.
  • The facility is not located within a cumulatively impacted community and you are submitting a request for modification that results in an increase in volatile organic compound (VOC) emissions only.
  • You are submitting a request for no emission increases or pure decreases in a permit modification.

Steps to submitting an APCD-114 Form:

  1. Complete APCD-114 Form in its entirety.
    • Questions #1-6: Use facility info from the APEN.
    • Questions #7-9: Use information generated in the EJ Summary.
    • Questions #10-11: If you are not applying for a General Permit, please skip these questions and leave blank. If applying for a General Permit, indicate which General Permit will be used for each source.
    • Question #12: Provide a map of your location.
    • Question #13: Report your facility’s emissions sources by completing the appropriate template table(s) provided below. Include information about emissions from the project modification, as well as the total facility emissions.
    • Question #15: Please provide information on buildings/structures located on-site and adjacent to the emissions source(s). Estimates are acceptable.
    • Question #16: Asks if this source has been modeled before. If the answer is “yes,” provide previous modeling demonstration(s).
  2. Send the completed APCD-114 Form to: cdphe_apcd_modelingdeterminations@state.co.us.
    • Note: There is no fee associated with the processing of APCD-114 Form.
  3. Once you submit the APCD-114 Form and supplemental information, you will receive a Determination of Modeling from the Division’s Permit Modeling Unit within 2 weeks of submission. (The process will take longer if all required information is not submitted). The determination from the Permit Modeling Unit will state whether modeling is required. You will include this Determination with your APEN submission. 
    • Note: If a “Determination of Modeling Required” is made, follow this Modeling Procedure Guidance
      1. For Construction Permits: the model assessment may be submitted to PMU concurrently with the CP submittal.
      2. For General Permits or Title V modifications: a model assessment must be submitted to the Permit Modeling Unit prior to submitting the General Permit or Title V modification, and a final Modeling Review Report completed by the unit must be submitted with the General Permit or Title V modification.

How to submit an air pollutant emissions notice (APEN)

Do I need to submit an APEN?

  • Emission sources that have uncontrolled actual emissions above APEN thresholds must file an APEN. 
  • APEN thresholds are different and dependent on whether the source is located in a nonattainment or attainment area. 
    • Volatile organic compounds (VOCs) and nitrogen oxides (NOx) are precursors to ozone. Businesses in the 8-hour ozone nonattainment area must therefore report at the nonattainment thresholds for those pollutants. All other pollutants are reported at the attainment thresholds.

  • Here is the list of all reportable hazardous air pollutants (HAPs) or non-criteria reportable pollutants. We recommend searching by CAS number as chemical names can vary. 
  • If your equipment/activity does not require you to submit an APEN, you can begin operating at any time. For more information read Allowable Activities Prior to Permit Issuance.
  • If your equipment/activity does require you to submit an APEN, but does not require you to obtain a construction permit, you can begin operating after you have submitted your APEN.
  • If your equipment/activity is required to obtain a construction permit, you must have an issued permit in place before starting operation. You must file the APENs before you start equipment operations that result in emissions.
    • Note: Different requirements apply to Title V sources. Please contact the permitting team if you have questions.
  • APENs must be renewed every 5 years, or sooner if changes occur (such as installation of new equipment, replacement of equipment, change of ownership, or significant change of emissions).

Steps to submitting an APEN:

  1. Identify the appropriate APEN(s) for your operation or equipment. If there is not a specific APEN type for your emission source, you may use the “General APEN” form.
  2. Review and complete the application completeness checklist.

  • NoteYour application will be rejected if it is filled out incorrectly, is missing information, missing required forms, or lacks payment for the filing fee. The Form APCD-100 and all applicable forms on that checklist are required with every application. The re-submittal will require a new filing fee. See our Application Rejection Frequently Asked Questions page for more information.
  • The following application types are exempted from the requirement to submit the Permit Application/Registration Checklist (Form APCD-100):
    • Air Pollutant Emission Notice (APEN) updates only (no changes to permit).
      1. Renewal of 5-year APEN term.
      2. Update to actual annual emissions, per AQCC Reg. 3, Part A, Section II.C.
  • APEN exempt sources.
  • Permit exempt sources.
  • Administrative permit amendments (including but not necessarily limited to name changes, changes in contact information, transfers of ownership, and typographical error corrections).
  1. Submit payment for your APEN(s).
    • The current filing fee for each APEN is $242.00.
    • To pay APEN filing fee(s) and General Permit fee(s) with a credit card, use the Air Pollution Control Division’s online payment portal
    • You may alternatively mail your complete application and check payment to:
      • Colorado Department of Public Health & Environment
      • APCD-SS-B1
      • 4300 Cherry Creek Drive South
      • Denver, CO 80246-1530
  2. Please submit the APEN(s), all supplemental attachments (including Letter of Concurrence for the EJ Summary, Modeling Determination, maps, and final Modeling Review Report, if required), a cover letter (optional), and copy of your payment receipts to: cdphe_apcd_ssp_application@state.co.us.


Contact us


If you are a small business and have a question regarding the application process, please contact:


For questions relating to environmental justice requirements, please contact:



If you have questions regarding modeling and modeling determinations, please contact:


For questions relating to Title V permits, please contact: