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2023 Air Emissions Reporting Update

Making the move from
MAERS  to  MIEnviro Portal words with arrow through a greenleaf

Information on this page is provided to help you prepare your 2022 MAERS data so reporting emissions in MiEnviro Portal will be easier.

View and download a print version of this page.

EGLE’s Air Quality Division (AQD) is updating the way air quality information is collected with a new online system called MiEnviro Portal (MiEnviro). This change will impact the way you report your 2023 air emissions to MiEnviro in early 2024. The rules and regulations have not changed.  The system we use to collect the data is changing from MAERS to MIEnviro. To smooth the transition, we will be providing information as it becomes available. This includes tips on things you can do in your 2022 MAERS report and additional guidance and training on the new system throughout 2023. 

You will continue to use MAERS and the Supplemental Control Template to report your 2022 emissions during the reporting season in January 2023 through March 15, 2023.  We will not be changing how your 2022 emissions are reported.  

MAERS data will be migrated to MiEnviro some point after March 2023.  Users will be able to review their source data in MiEnviro throughout 2023 prior to the 2023 reporting season, which begins in January 2024.  Current MAERS users will be notified when MiEnviro is available to use and when they can register for trainings.  

For easier transition from MAERS to MiEnviro, we recommend the following changes to your 2022 MAERS report:

  1. Make sure your emission unit names match the emission unit names in your permit.
    Matching emission unit names will allow the data to migrate correctly.  Mismatched names could cause possible issues needing correcting in MiEnviro.
  2. Remove any Reporting Groups and report all activities for every emission unit.
    Reporting groups will not be available in MiEnviro.  Alleviates correcting the data in MiEnviro, which will be more difficult for users to use their first year. As MiEnviro doesn’t have Reporting Groups, removing them in the 2022 report prior to the data being migrated to MiEnviro will help the data make sense to users in MiEnviro.
  3. Add stacks/release points to emission units when the emissions are not fugitive.
    We encourage users to add stacks/release points to emission units in the 2022 MAERS report if you do not want emissions to be reported as fugitive in MiEnviro.
  4. Add control devices to emission units where appropriate.
    Reporting activities at the emission unit and adding control device codes will align control devices correctly with emission units and the data will make more sense when migrated to MiEnviro.
  • To assist facilities, the AQD has updated some emission unit names in MAERS for you. 

    For example, where:

    the permit emission unit name is EUBoiler01, and the MAERS emission unit name is EU-Boiler-01,


    the permit emission unit name is EUBoiler01, and the MAERS emission unit name is EU1Boiler,

    the AQD changed the emission unit name in MAERS to EUBoiler01 to match the emission unit name in the permit. 

    The AQD did not make any changes to emission unit names where the differences were less obvious than the above examples. Facility users should update emission unit names in your 2022 MAERS report to match the emission unit names in their permit(s).

    How to update your emission unit name in MAERS

    1. Click on the Emission Unit tab.
    2. Select View/Edit next to the emission unit you want to edit.
    3. Edit the emission unit name and save it. 

    Watch a short "how to" tutorial: Matching Emission Unit Names to Your Air Permit.

    How will Emission Unit data in MiEnviro Portal be different?

    In MAERS, emission units can be added/named on the Emission Unit tab.  In the new system, emission unit information will be added/named at the “Site” level, which takes place prior to emissions reporting.  The emission reporting feature will be populated with specific data from the “Site” level.


  • MiEnviro will not support the use of reporting emissions by grouping emission units into Reporting Groups as you can opt to do in MAERS.  Below are instructions to remove your reporting groups from your 2022 MAERS report.

    How to remove Reporting Groups from MAERS

    1. Click the Reporting Group tab and delete all reporting groups by clicking on the “Delete” icon.
      NOTE: Prior to deleting an RG, take a screenshot or have a PDF available of the data for use when adding the same activity to an emission unit.
    2. Click on the Activity & Emissions tab. Verify there are no reporting groups listed.
      NOTE: This will make every emission unit that was part of an RG in your report appear on the Activity & Emissions tab.
    3. View/Edit each emission unit on the Activity & Emissions tab and choose “Add New Activity” for every activity an emission unit performs.
    4. Add the activities and emissions for each emission unit. More specific information on adding activities and emissions can be found in the MAERS User Guide.

    Watch a short "how to" tutorial: Removing Reporting Groups.

    If you opt to keep your Reporting Groups in the 2022 MAERS emissions report

    1. Your data will still be migrated to the new system but will require modifications for 2023 emissions reporting in MiEnviro.
    2. Understanding the data in the new system may be more confusing prior to making the necessary modifications.
  • In MAERS, you were not required to include stacks for some emission units. When a stack was not included in MAERS, the emissions were considered fugitive and reported as fugitive.

    Fugitive emissions are released lower to the ground and are not shown as lifted away from the public. In computer models that look at how pollutants affect the population, fugitive emissions are looked at and measured differently and may indicate higher concentrations of pollutants in the breathing zone than are truly there.

    In MiEnviro, you will need to add a stack/release point to every emission unit.  In MiEnviro, “fugitive” is a release point option.  This means you can either add a stack/release point or select fugitive as the stack/release point in MiEnviro.

    We encourage users to add stacks/release points to emission units in the 2022 MAERS report if you do not want emissions to be reported as fugitive.

    How to add Stacks in MAERS

    1. Stacks/release points are added on the Stack tab.
    2. Stacks/release points are associated with an emission unit on the Emission Unit tab.
    3. Some required stack/release point data is collected on the Supplemental Control Template because MAERS does not have the appropriate fields or capabilities.

    How stack data will be similar/different in MiEnviro Portal

    1. Stacks will be referred to as release points.
    2. Stacks/release points will be added at the “Site” level and not at the time of emissions reporting.
    3. All required stack/release point data will be collected in MiEnviro.  The rules have not changed. If you weren’t required to report stack information in MAERS, you will not be required to report it in MIEnviro. However, reporting stack information that isn’t required often makes it easier to report emissions more accurately.
    4. If users do not add a release point to an emission unit, they must select “fugitive” as the release point. Currently in MAERS, if there isn’t a stack/release point associated with an emission unit, the emissions are reported as fugitive, it’s just not as obvious as it will be in the new system.
    5. The same information collected in MAERS for stack/release points, will still be collected in the new system.   More specific information on stack data can be found in the MAERS User Guide.
  • Taking control efficiencies into account when it is accurate and appropriate is important. Users who are reporting control efficiencies on the Emissions tab, should add control device codes to emission units on the Emission Unit tab in the 2022 MAERS report.

    How to add Control Device Codes in MAERS

    1. Add control device codes to emission units on the Emission Unit tab/form.
    2. Scroll to the bottom of the Emission Unit tab and click on the plus sign near Control Device Codes and select one or more Control Device Codes as appropriate.
    3. Define the control device in the Supplemental Control Template and outline the configuration of control devices within control pathways.

    Watch a short "how to" tutorial: Adding Control Efficiencies.

    How will control devices be different in MiEnviro Portal?

    1. Users cannot use a control efficiency for a pollutant without having a release point and control pathway associated with an emission unit.