Emission calculations

Detailed emissions calculations for a facility must be included in a permit application and are required in order to complete Form GI-07 (Facility Emissions Summary) or CAP-GI-07, and to determine the type of permit or permit amendment needed.

Detailed emission calculations must be included in the permit application in two ways:

  1. Printed out in the permit application; and
  2. In an editable spreadsheet format. This can be included on a CD with the permit application, or emailed to MPCA upon request. In the editable spreadsheet format, all formulas/equations need to be provided in the calculated cells of the spreadsheet.

Calculating potential emissions

There are multiple ways for calculating potential to emit, including, but not limited to, using published emission factors, material balance methods, and using data derived from direct measurement of emissions.

If you are using emission factors, use the most current emission factors available for each pollutant. An "emission factor" is defined in Minn. R. 7005.0100, subp. 10a.

The emission factor listed in the Compilation of Air Pollutant Emission Factors (AP-42), fifth edition, U. S. Environmental Protection Agency (EPA), Technical Support Division, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711, (January 1995) is available on the EPA Web site: HTML icon Emissions Factors and AP 42 - Compilation of Air Pollutant Emission Factors.

When calculating your potential emissions, describe any bottlenecks or physical limitations in your process(es) that have been taken into account to restrict your potential-to-emit.

Also describe any permit limits you plan to take to restrict your potential-to-emit (fuel type and/or usage, hours of operation, bottlenecks, etc.). Information on how to propose limits can be found on the MPCA Web site. Describe the limiting factors, citing any rules that apply [e.g., Standards of Performance for Stationary Sources (NSPS, 40 CFR part pt. 60), Best Available Control Technology (BACT)]. The associated limit must be used to calculate your potential-to-emit after permit limits. If you used vendor certification or stack test data to limit your potential-to-emit, the factor you used will become your permit limit. Include all proposed limits on Form CD-01, and wherever else instructed in the permit application forms.

Calculating actual emissions

Actual emissions can be calculated or determined in a number of ways. Min. R. 7019.3030(A) provides a hierarchy of preferred methods for calculating the facility’s actual emissions as follows:

  1. Continuous emission monitor data (Minn. R. 7019.3040);
  2. Performance test data (Minn. R. 7019.3050);
  3. VOC material balance(Minn. R. 7019.3060), SO2 material balance (Minn. R. 7019.3070), emission factor (Minn. R. 7019.3080), or enforceable limits (Minn. R. 7019.3090); or
  4. Facility proposal (Minn. R. 7019.3100).

MPCA resources for how to calculate emissions