All facilities with air permits must submit an annual emissions inventory report to the MPCA that tracks the facilities' actual emissions of major pollutants, as directed in their permits. We use emission inventories to:

  • calculate each facility's annual emission fees
  • assess health risks from air pollution
  • support air quality modeling
  • evaluate the effectiveness of our air regulations
  • determine where air pollutants end up in the environment

Air emissions inventory reporting

Reporting requirements and guidance

Annual inventories must be completed by April 1 each year. Large emissions inventory type permit holders and facilities with registration Option C or Option D permits must submit air emission inventories using the MPCA e-Services.

To submit an emission inventory for a given facility, you must be set up as the “submitter” for that facility. (See the "quick guide" to learn how.)

Option C and D registration permits

Large facilities

Option B registration and nonmetallic general permits

Facilities with a registration Option B permit or nonmetallic general permit must complete the appropriate form below and email it to or mail it to Rachel Olmanson at the MPCA in St. Paul.

Emission factor updates

The EPA revised particulate matter (PM) emission factors for natural gas, process gas, and liquefied petroleum (LP) gas because it determined the AP-42 factors for condensable PM emissions were too high.

The revised emission factors are used in the relevant calculations on MPCA e-Services. The unrevised emission factors are still available in AP-42/WebFIRE.

The EPA also revised methane and nitrous oxide emission factors for coal, coke, municipal solid waste, tires, and biomass fuels (except wood and wood residuals). The agency discovered minor errors in the conversion from kg/TJ (IPCC factors) to kg/mmBtu that didn't adjust for the factors' different heat content basis.

Air toxics

Currently, Minnesota facilities with air permits voluntarily report emissions of air toxics every three years. Air toxics include the hazardous air pollutants listed in the Clean Air Act, and other pollutants of concern in Minnesota and the Great Lakes. The MPCA strongly encourages facilities to submit air toxics emissions data, even when it's not required. See Pollutant categories for air toxics for more information.

The agency is now considering making air toxics reporting annual and mandatory. We held a webinar about the current air toxics reporting structure and a potential reporting requirement. Through the webinar and subsequent comment period, we heard from more than 60 Minnesotans and organizations. Learn more:

If we move forward with making air toxics reporting mandatory, there will be additional opportunities for public input.

Stay connected

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Greenhouse gases

Facilities with capped, Option D registration, or Title V permits must report greenhouse gas (GHG) emissions. MPCA e-Services automatically calculates GHG emissions from combustion sources. The agency calculates emissions for carbon dioxide, nitrous oxide, and methane using emission factors from EPA's mandatory reporting rule.

Some companies also have to report on emissions of hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride, which are considered high global warming potential greenhouse gases. Learn more:


Facilities with actual mercury emissions of three pounds per year or more (after controls) must submit an annual emissions inventory via MPCA e-Services. Electric utilities must report mercury emissions of any amount each year.

Facilities that provide electric energy at retail in Minnesota from power generated outside the state can report via email to Azra Kovacevic (see contact below).

MPCA will not take action if your facility does not report its mercury emissions from electricity generation sources located outside Minnesota, but provides electric energy at retail or wholesale in Minnesota.

1-bromopropane (1-BP) – new HAP

1-bromopropane CAS No. 106-94-5 (also known as 1-BP, n-propyl bromide, and nPB) is now a hazardous air pollutant (HAP), and MPCA has incorporated it into its air emission inventory. This new HAP is included in the e-Services Air Emission Inventory – CEDR online reporting site as an air toxic pollutant. In e-Services, it is called “BROMOPROPA,1”. All air toxics are included in the MPCA emission inventory every three years. Facilities that will be using or emitting 1-bromopropane for the 2023 emission inventory year and reporting in 2024 should prepare to track any necessary information to enable 1-BP emissions estimates for calendar year 2023.

Emission inventory fees

Between February and April, the MPCA sends invoices to facilities for their annual air emission fees. The fee is calculated using the most recent finalized inventory. For example, a facility's 2022 fee is calculated based on its 2021 emissions data.

The emissions fee calculation uses a “fee target," which is the amount appropriated by the Legislature to fund the MPCA's air program. The fee target is divided by the tons of all (un-capped) billable pollutants in the most recent annual emission inventory, to determine the dollar per ton fee.

Fee year Emission inventory year Cost per ton
2023 2021 $149.66
2022 2020 $171.64
2021 2019 $145.23
2020 2018 $115.32

Permitted facilities are billed based on the per-ton fee and their emissions of nitrogen oxides, lead, particulate matter less than 10 microns, sulfur dioxide, and volatile organic compounds. Learn more:

Emissions data