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An air permit addresses all sources of air pollutant emissions at a facility. The need for an air permit is based on whether the entire facility’s potential air emissions exceed permitting thresholds or if certain New Source Performance Standards (NSPS) apply. The required air permit type will depend on your actual emissions and which federal air regulations apply. The following steps provide the process for determining whether your facility requires an air permit and, if so, which permit type may be the best fit for your business. 

Step 1: Review the online training

Reviewing the self-paced online training, Do I need an air permit? is a fundamental first step. The training explains the types of air pollutants, common air emission activities, air permit types and exemptions, and state and federal air regulations. Included is a facility assessment and emission calculation examples.

Step 2. Assess your facility 

Air pollutants are released from activities that create dust or fumes, whether inside or outside. Some activities include the use of VOC-containing materials such as:

Create a layout, flow chart, or list of all air emission equipment and activities at the facility. This involves walking through the facility, following each operation from beginning to end, and recording any items that burn fuels and/or generate dusts, vapors, or odors. Collect basic information regarding equipment and activities. Information may include the materials used (type and quantity with safety data sheets), equipment rates or capacity (HP, Btu, cubic feet, gallons, pounds), hours of operation, and make and model of equipment.

Step 3: Exempt source or insignificant facility

Small sources of air emissions, such as insignificant facilities, may not require an air permit. Use the calculator tool below to see if your facility qualifies as an insignificant facility.

Auto body, coating, and woodworking facilities; concrete manufacturers; and gasoline service stations may be conditionally exempt from needing an air permit. All conditionally exempt sources have technical standards to follow and most require a notification to be submitted to MPCA.

If your facility does not qualify as an insignificant facility or conditionally exempt source, you may qualify for the smallest and simplest state permit, known as a registration permit. These permits contain simplified regulations intended to make compliance easy. Continue to the next step to calculate your air emissions and see if a permit is required. 

Step 4: Calculate your facility’s PTE

If your facility's potential-to-emit (PTE) exceeds one or more air pollutant permitting thresholds, an air permit is required. PTE is the maximum capacity of an emission unit or source to emit pollutants under its’ physical and operational design while in production at the maximum number of hours, typically 8,760 hours per year. PTE needs to be calculated for all equipment and processes that emit air pollutants. Most equipment and processes will emit more than one air pollutant.

For example, the maximum hourly capacity for a natural gas boiler is the maximum heat input identified on the boiler’s nameplate. The potential emissions are based on the boiler operating 24 hours a day, 7 days a week (8,760 hours per year). Burning fuel produces criteria air pollutants, air toxics and greenhouse gases. 

The pollutants emitted and rate of emissions for equipment or processes can be identified through several methods. See guidance on calculating air emissions.

  • Air emissions calculators are available to help determine your PTE. Some spreadsheets will require customization to better represent the products and processes of your facility.
  • Larger sources may be required to use the MPCA’s air permitting emission spreadsheets for certain activities when submitting a permit application.

After calculating PTE for the entire facility, sum the amount of each pollutant emitted. If the facility’s PTE exceeds one or more permitting threshold, continue to the Step 5: Calculate your actual emissions; otherwise, go to Step 6: Review federal air regulations.  

Step 5. Calculate your actual emissions

Actual emissions are the total amount of pollutants emitted based on your facility’s actual material use, production rates, and operating hours. The pollutants and rates of pollutants emitted for equipment or processes when calculating PTE can also be used to calculate actual emissions. Similar to PTE calculations, air emissions calculators are available to help determine your facility’s actual emissions. 

Compare your facility’s total actual emissions to permit limits to help identify the type of permit that is the best fit for your activities. 

Step 6. Review federal air regulations

There are two types of federal air regulations, New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP); either or both regulations may apply. Review the lists of NSPS and NESHAP to determine if any apply to the facility. If an NSPS or NESHAP is applicable, you may be required to notify the United States Environmental Protection Agency (EPA) and/or the MPCA. Additionally, NSPS applicability can influence whether a facility requires an air permit and the specific permit type.

Step 7: Apply for an air permit

If you need an air permit, use your calculated actual emissions and any applicable federal air regulations to determine the appropriate permit. There are five air permit types. The forms needed to apply for an air permit are found on the air permit application forms page. 

Registration permits

Many small businesses may qualify for the smallest and simplest state permit, known as a registration permit. There are four registration permit options. Section 16 of the RP-01 form contains all required application forms and content. The registration permit application review completeness checklist (aq-f0-acc05) may be used to check your application before submitting.