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Minnesota rules require many facilities that produce air emissions to conduct performance testing (also called "stack testing") that:

  • quantifies facility emissions.
  • determines the physical, chemical, or aesthetic properties of the emissions.
  • in some cases, measures the performance of emission-control equipment.

Most permits require recurring performance tests on a set schedule based on factors including compliance history, previous test results, applicable requirements, stringency of limit, and use of emission factor. If warranted, MPCA staff may reset the frequency after a test, which becomes effective upon issuance of the review letter and will be incorporated in the facility’s permit.

Facilities subject to performance-testing requirements must:

  • notify the MPCA and provide a test plan at least 30 days before the scheduled test unless required otherwise.
  • arrange for a pretest meeting with MPCA staff at least seven days before the test.
  • submit a test report to the MPCA no later than 45 days after the test.

It is your responsibility to contact MPCA staff if you cannot meet these deadlines or if you need to reschedule after the test plan is approved. Do not test prior to receiving approval.

Testing companies and methods 

Independent testing companies conduct performance tests. The Source Evaluation Society offers a list of experienced testing companies.

The U.S. EPA's Air Emission Measurement Center lists the test methods available for emission measurement.

Test plans

Test plans include the equipment to be tested, proposed methods, and planned operating conditions for the equipment during the performance test. Test plans must be complete, accurate, and approved by the MPCA prior to testing. If the submitted test plan is missing necessary information, MPCA staff will request a revised plan. Once satisfied, the agency will provide written approval of the plan that may include clarifications or modifications. Reference Minn. R. 7017.2030 to verify that you included all required information.

Pretest meetings

During the pretest meeting, MPCA staff will discuss the test plan with you and your consultant to answer questions and ensure procedural as well as technical requirements will be met. Pretest meetings are typically held over the phone.

Submitting test plans

Email test plans to SubmitStackTest.PCA@state.mn.us and your assigned stack test staff member (if known).

Test reports

Test reports must be complete, accurate, and meet all requirements of Minn. R. 7017.2035. 

Test report required elements

Performance test reports must include certification statements using the certification form:

Test reports must include data summarizing operating conditions during the test and verifying the test was performed at worst-case conditions. MPCA staff typically set limits on production and control equipment for tests not completed at worst-case conditions. Strip charts, electronic data retrieved from continuous monitors, or manually recorded rates must be included in the test report and summarized on one of these forms:

In addition to the summary form, test reports must contain emission and control equipment operating conditions for each run, averaged over each run, and averaged over three runs to provide a final average value for the test. During the test, readings of discrete data from monitoring instruments must be recorded a minimum of every 15 minutes, or other reasonable time interval as approved. 

Submitting test reports

Email the stack test report as an attached PDF to SubmitStackTest.PCA@state.mn.us. The email message body must include all of these elements:

  1. name of regulated party (and facility name if different)
  2. facility contact
  3. agency interest ID number or permit number
  4. date of performance or certification test
  5. name of MPCA staff who sent approval
  6. date of submission

Noncompliance reporting

Report all periods of noncompliance with emission or other limits — even during engineering tests — to the MPCA. Operating at a rate other than that allowed by the current air permit must also be reported. Reporting includes adding periods of noncompliance to the quarterly or semiannual deviation report.

Air permit compliance forms

Submitting routine compliance reports

Send routine compliance reports to AQRoutineReport.PCA@state.mn.us. Include the submission date and a brief description as part of the routine report document title:

  • Example: 1-28-24, DRF-1, DRF-2, CR-04
  • Example: 1-28-24, Pt 60 MM Compliance Report
  • Example: 1-28-24, DRF-1 and EQUI 1 NOx

Frequently asked questions about reporting test results

Am I required to submit the results of an engineering performance test that I conduct for my own information?
If an engineering test indicates noncompliance with a limit, the company must inform the MPCA. Generally, the pollutant, emissions, and operating conditions can be summarized and reported in place of a complete report, unless a more detailed report is requested. Results of a compliant engineering test need not be provided, unless requested by the MPCA. All periods of noncompliance with emission or other limits must be reported to the MPCA.

If early results indicate a test failure, can I stop the test and try again later? 
Each performance test must consist of at least three separate test runs. If after conducting one or more test runs, the company determines that an emission limit has been exceeded, the MPCA should be contacted for further guidance. A detailed description of sampling or other problems experienced during the test should be included in the executive summary of the test report. Regardless of the number or length of test runs, data from an aborted emissions test may be used to establish violations.

What if my test results indicate noncompliance?
The unit must be retested within 30 days of the MPCA notice of noncompliance unless a compliance plan is submitted and approved by the MPCA. The period of noncompliance begins on the date of the initial noncompliant test. Therefore, you should take immediate measures to minimize emissions without waiting for the MPCA's formal notification.

Can I use the data from my test report for emission fee inventory purposes?
Yes. Minnesota rules require emission calculations based on an established hierarchy. In the absence of continuous emission monitor data, a performance test must be used. When a performance test for PM, PM10, PM2.5, CO, NOx, SOx, VOC, or Pb is conducted and meets the requirements of Minn. R. 7017.2001-2060, the results must be used to calculate emissions, unless specified otherwise by Minn. R. 7019.3000-3100. It is the company’s responsibility to ensure the results of performance tests are accounted for in their annual emission inventory. The final decision to approve the emission factor for any given inventory year will be made by the Emission Inventory Coordinator.

How do I submit confidential information as part of a test report?
Claims of confidentiality for test report information must have a statutory basis and be included in a cover letter that accompanies the test report. See Minn. R. 7000.1300 and Minn. Stat. §§ 13.37 and 116.075 to determine whether your information meets the criteria. In the cover letter, identify the confidential information and explain the statutory basis for the claim. Provide both a public and confidential copy of the test report.