APENs and air permits

Any business in Colorado that emits air pollution may be required to report its emissions and/or apply for a permit. Submitting an Air Pollutant Emissions Notice (APEN) is required to report your emissions, apply for a permit, or modify a permit.
 
Your APEN will be rejected if it is filled out incorrectly, is missing information, or lacks payment for the filing fee. The re-submittal will require a new filing fee. See our Application Rejection Frequently Asked Questions page for more information.

Do you need an APEN or air permit?

  • Introduction to APENs video.
  • Detailed guidance for calculating your emissions.
  • APEN/permit threshold table.
  • Ozone non-attainment area boundaries.
  • Common APEN and air permit exemptions.
  • APEN update guidance.

What are the fees? 

Permits

Find forms to apply or modify (including APENs), and permitting process guidance.

Oil & gas APENs

If you just need an APEN and are not applying for a permit.

General Permits

General permits offer a streamlined approach, they're available for land development activities, diesel engines, natural gas RICE engines and other oil and gas operations. Sources that can meet the criteria of emissions limitations and other operating conditions may qualify for a general permit.

Administrative changes

Cancel, change ownership or company name, provide notice of startup, alternate operating scenario, relocation notice, or self-certify.

Resources

Permits

Find APENs and resources to apply for, modify or renew a permit

Administrative changes

Cancel, change of ownership or company name, provide notice of startup, alternate operating scenario, relocation notice, or self-certify. 

Resources