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Potential to Emit

Business owners commonly need assistance in determining a business’s potential to emit air pollutants. The definition provided here is found in Section 39.5 (1) in the Illinois Environmental Protection Act.

Potential to emit (PTE) is defined as:

The maximum capacity of a stationary source to emit any air pollutant under its physical and operational design. Any physical or operational limitation on the capacity of a source to emit an air pollutant, including air pollution control equipment and restrictions on hours of operation or on the type or amount of materials combusted, stored, or processed, shall be treated as part of its design. This definition does not alter or affect the use of this term for any other purposes under the Clean Air Act, or the term "capacity factor" as used in Title IV of the Clean Air Act or the regulations promulgated thereunder.

Under this definition, when calculating your PTE you must assume all emission units at a source will run 8,760 hours per year at full production capacity, unless your operation is restricted by a federally enforceable permit limitation.


  • For purposes of a Federally Enforceable State Operating Permit, you must add your PTE for similar pollutants from all emission units at your site.
  • You must total all the emission units at your site, whether or not they are covered by the same air permit.

For small business assistance contact:

Illinois Dept. of Commerce and Community Affairs 
620 E. Adams 
Springfield, IL 62701
Small Business Environmental Assistance Helpline