The air emissions inventory provides a comprehensive and detailed estimate of emissions of criteria air pollutants (CAPs), air toxics, and greenhouse gases (GHGs) reported by facilities that have air permits, also known as point sources. More information on these pollutants is available on the MPCA’s air pollutants page.
The MPCA also compiles a statewide and county-level emissions inventory every three years. This broader inventory accounts for nonpoint sources, including mobile sources and includes emissions of both criteria pollutants and air toxics. Nonpoint emissions data is available here: Statewide air emissions data.
Facilities with air permits are required to submit an annual air emissions inventory report to comply with the Minnesota Emission Inventory Rule. Most facilities report actual emissions of major pollutants including the six criteria pollutants: lead, particulate matter, nitrogen oxides, sulfur dioxide, carbon monoxide, and volatile organic compounds as a precursor to ground-level ozone, plus ammonia. Some facilities also report emissions of air toxics, GHGs, and mercury.
We use emission inventories to:
- calculate each facility's annual emission fees
- assess health risks from air pollution and identify areas of potential concern; see Air emissions risk analysis and MNRISKS for more information
- support air quality modeling
- evaluate the effectiveness of our air regulations
- determine where air pollutants end up in the environment
- provide data to national and regional efforts, like the National Emissions Inventory
Air emissions inventory reporting and guidance
Facilities with air permits must submit an annual emissions inventory report by April 1 each year. All facilities with air permits, except for registration option B and nonmetallic general permits must submit air emission inventories using MPCA e-Services.
- Getting started with 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.
- Registration option C and D 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 or option D air permit (including hot mix) 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 process emitting VOCs or particulates. The training concludes with a demonstration of entering air toxic emissions in MPCA e-Services. The MPCA will update this training video prior to the start of the 2026 Emissions Inventory reporting period.
- Large facility
Includes facilities with general manufacturing, capped, registration option A, and individual state and federal permits.
- Registration option B 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.
Forms and guidance:
- option C and D registration permits
- large facilities (includes facilities with general manufacturing, capped, registration option A, and individual state and federal permits)
- option B or nonmetallic general permits
Getting started with 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
- 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 or option D air permit (including hot mix) 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 process emitting VOCs or particulates. The training concludes with a demonstration of entering air toxic emissions in MPCA e-Services. The MPCA will update this training video prior to the start of the 2026 Emissions Inventory reporting period.
Large facilities
Includes facilities with general manufacturing, capped, registration option A, and individual state and federal permits.
- 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: new rule requirements
In 2025, the MPCA adopted new rules governing air toxics emissions reporting as directed by the 2023 Legislature. See the rulemaking page on air toxics emissions reporting.
Previously, facilities with air permits voluntarily reported air toxics emissions every three years. The new rule will require air permitted facilities (except registration option B permits) operating in the seven metropolitan counties (Anoka, Carver, Dakota, Hennepin, Ramsey, Scott, and Washington) to report air toxics emissions each year starting with the 2026 Emissions Inventory, due April 1, 2027.
MPCA will continue to strongly encourage facilities operating outside the seven metropolitan counties to continue to voluntarily report air toxics emissions. The next air toxics reporting year will be the 2026 Emissions Inventory. See Pollutant categories for air toxics for more information on reporting air toxics emissions.
MPCA will continue to strongly encourage facilities operating outside the seven metropolitan counties to continue to voluntarily report air toxics emissions. The next air toxics reporting year will be the 2026 Emissions Inventory. See Pollutant categories for air toxics for more information on reporting air toxics emissions.
Greenhouse gases
Facilities with capped, registration option D, 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.
Starting with the 2026 emissions inventory, facilities located in the seven metropolitan counties will be required to report mercury emissions as part of the requirements of the newly adopted Air Toxics Emissions Reporting rule. Facilities outside the seven metropolitan counties will continue to follow the current requirements.
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 rules that relate to this fee are Minn. R. 7002 and 7005.
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.
Facilities with air permits are billed annually based on the total number of tons of nitrogen oxides (NOX), lead (Pb), particulate matter less than 10 micrometers (PM10), sulfur dioxide (SO2) and volatile organic compounds (VOCs) that they emit into the atmosphere. The air emission fee for a facility is calculated by multiplying the emission inventory billable emissions for the facility, by cost ($) per ton. Option B registration permits and facilities emitting less than one-ton of billable emissions pay a flat fee rate.
Learn more:
| Fee year | Emission inventory year | Cost per ton |
|---|---|---|
| 2025 | 2023 | $162.94 |
| 2024 | 2022 | $162.93 |
| 2023 | 2021 | $149.66 |
| 2022 | 2020 | $171.64 |
Emissions data
Tools and resources that can be used to view and explore 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.
- MNRISKS air pollution scores - this map is produced using the MPCA's MNRISKS model, which uses reported emissions, air dispersion modeling, and health benchmarks to determine cumulative pollution risks and environmental justice areas; the map includes air pollution from permitted facilities, traffic, residential and commercial heating, and other sources
- U.S. EPA’s AirToxScreen - a screening tool that that provides communities with information about health risks from air toxics nationwide