All facilities with air permits must submit an annual emissions inventory report to the MPCA that tracks actual emissions of major pollutants, as directed in the 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 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.)
- Video: Submitting an inventory and assigning role (11 min.)
- Air emission inventory: Quick guide - account creation and registration
Option C and D registration permits
- Training: Air emissions inventory reporting introduces reporting requirements and provides step-by-step guidance to complete the annual emissions inventory report. Registration permittees with an Option C, Option D, and Option D Hot Mix air permit will learn how to create and manage accounts in the electronic service, enter air emissions data, and submit the annual air emissions inventory report successfully.
- Training: Air toxic emissions reporting a review of air emissions reporting of air toxics. It includes information on air toxic pollutants, and how to identify them at your business. The training provides step-by-step instructions with examples on how to calculate air toxics from a volatile and particulate emissions process. The training concludes with a demonstration of entering air toxic emissions in MPCA e-Services.
- Air emission inventory: Quick guide to electronic reporting
- Air emission inventory: Registration Option C permit
- Air emission inventory: Registration Option D permit
Large facilities
- Air emissions inventory: Quick guide to electronic reporting for large EI types
- Air emission inventory: Large EI type
- Video: Air emissions inventory: Updating facility inventory for large EI types (20 min.)
- Video: Air emissions inventory: Updating throughput/emissions for large EI types (20 min.)
Option B registration and nonmetallic general permits
Facilities with a registration Option B permit or nonmetallic general permit must complete the appropriate form below. Option B permittees may email it to optionbreport.pca@state.mn.us or mail it to Corey Jarrett at the MPCA in Saint Paul. Nonmetallic general permittees must mail their form to Corey Jarrett at the MPCA in Saint 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
The MPCA is planning new rules governing air quality, as directed by the 2023 Legislature. See the rulemaking page on air toxics emissions reporting.
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.
Greenhouse gases
Facilities with capped, Option D registration, or Title V permits must report greenhouse gas (GHG) emissions. MPCA e-Services automatically calculate 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.
Mercury
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 2025 fee is calculated based on its 2023 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 |
|---|---|---|
| 2025 | 2023 | $162.94 |
| 2024 | 2022 | $162.93 |
| 2023 | 2021 | $149.66 |
| 2022 | 2020 | $171.64 |
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
- Permitted facility air emissions data – The reported air emissions for permitted facilities in Minnesota.
- Statewide air emissions data – Statewide and county emissions for criteria air pollutants and air toxics. View via map, chart, or data table.
- Greenhouse gas emissions data – Summary of greenhouse gas emissions in Minnesota.
- MPCA's Pollution Report addresses the amount of water and air pollution emitted in the state, and the percentage change since the previous report.