Air Emissions_Content Page_Air Reporting System ARS Tutorials

Air Emissions Inventory (EI) Schedule, Directions, Help and FAQs

Schedule for Calendar Year 2024 EI Data

DateBenchmark
Jan. 13, 2025First date to report an EI or generate an Under-Thresholds-Notification (UTN)
March 1, 2025EI or UTN due – unless an extension to March 15, 2025 is requested in ARS (extensions will not be granted via email)
By May 31, 2025Environmental fee statements issued to facilities, with payments due within 30 days
June 30, 2025EI certifications due

Important Updates

Awareness of Publicly Facing Data

Submitting accurate and timely emissions inventory data is important. The DNR will continue to assist sources during reporting season (January - March).

Emissions inventories are due annually by March 1 (or March 15 with a submittal extension) and emissions inventory data is transferred by DNR to EPA once each year for the previous calendar year’s data (around July).

Emissions inventory data submitted by owners and operators to DNR in ARS is widely available on DNR, DHS and EPA public access sites:

New Regulated Pollutant

1-Bromopropane (1-BP) was added to the hazardous air pollutants listed under section 112(b) of the Clean Air Act, effective Feb. 4, 2022. In addition to the air contaminants listed in Table 1 of of ch. NR 438, Wis. Adm. Code, the department requests reporting of 1-BP emissions to the annual emissions inventory. NOTE: A source’s major source status and applicable requirements may have changed as a result of the addition of 1-BP. For more information, see 1bp-q-and-a-document-final.pdf (epa.gov).

Revised Air Emissions Inventory Reporting Rule

The following changes were made to Wisconsin’s air emissions inventory reporting rule (ch. NR 438, Wis. Adm. Code) and are effective starting Aug. 1, 2022:

  • Major sources in nonattainment areas, sources with the potential to emit equal to or greater than 100 tons per year of criteria air pollutants or ammonia, and sources with actual emissions of 0.5 ton per year of lead are now required to report annual emissions of all criteria air pollutants and ammonia, regardless of the reporting thresholds in Table 1 of ch. NR 438. Wis. Adm. Code.
  • An emissions reporting requirement was added to the rule for sources that directly emit fine particulate matter (PM2.5).
  • Particulate reporting requirements were clarified to apply to primary emissions, where primary emissions are directly emitted into the atmosphere, rather than secondary particulates formed through atmospheric chemical reactions.
  • An annual emission inventory may exclude emissions from specific emission units, operations, or activities now listed in ss. NR 438.03(1)(am)(3) and (4), Wis. Adm. Code.
  • State administrative code language was aligned with federal emissions reporting terminology and updated to reflect DNR’s current emissions inventory reporting process.
  • The requirement for the emissions inventory certification signature moves from the owner or operator to the Responsible Official under s. NR 438.03(5)(c), Wis. Adm. Code.

Facilities must comply with the updated rule starting with 2023 air emissions inventory reporting for calendar year 2022 emissions.

Directions

The Air Reporting System (ARS) allows companies to report annual air emissions on the internet using web-based software.

  1. Determine whether emissions inventory reporting is required (review the FAQ);
  2. Follow the Credentials and Access instructions; and
  3. Follow the EI and EI Certification Basic Steps or Under-Thresholds-Notification (UTN) Basic Steps instructions.

Note: Relevant directions for reporting in ARS are also provided throughout ARS (visit the Page Specific Help link on the left side of the screen in ARS).

Help

DNR's Dec. 6, 2023 webinar walks through the 2023 ARS updates.

DNR’s Dec. 8, 2022 webinar walks through ARS, including the 2022 ARS updates.

For assistance with Switchboard credentials, click on Need Assistance? to request help or Instructions, FAQ and Troubleshooting for detailed instructions and troubleshooting tips.

For EI questions and concerns, contact:

Direct EI related feedback to the Metrics and Emissions Inventory Coordinator: Megan Corrado.

FAQ

What are the most recent changes to ARS?

DNR’s Air Emissions Inventory Updates fact sheet lists recent changes made to ARS.

Is there a spreadsheet that summarizes ch. NR 438, Wis. Adm. Code pollutants and thresholds?

The DNR has prepared an Excel spreadsheet that provides information about the pollutants covered by Wisconsin's Air Toxics rule (ch. NR 445, Wis. Adm. Code), permit rules (ch. NR 407), and emissions inventory reporting rules (ch. NR 438). The table contains reporting levels for these pollutants, as well as emissions thresholds, standards and control requirements. In addition to combining information from several rules, the spreadsheet offers useful search and sorting functions.

Is there a table summarizing annual reporting requirements?

Yes. The document Universal Air Reporting Requirements and Due Dates [AM-648] summarizes common state air reporting requirements

How does a permitting exemption impact EI?

A permitting exemption has no impact on who should report an EI. The EI requirement is driven by the criteria listed in question Who is required to submit an EI?.

Why is a facility included in the annual EI emailing?

All facilities included in the annual EI correspondence may need to submit an EI or UTN and include:

  • Facilities that had an active permit or permit application during the EI year.
  • Facilities that exceeded reporting thresholds for a pollutant in Chapter NR 438, Wis. Adm. Code, for the previous EI year.
  • Facilities DNR has asked to submit an EI.

Who is required to submit an EI?

(a) Except as provided under s. NR 438.03(1)(am), Wis. Adm. Code, any person owning or operating a facility that emits an air contaminant in quantities above applicable reporting levels, except indirect sources of air pollution, shall annually submit to the DNR an emissions inventory of annual, actual emissions or, for primary particulate matter, primary PM10, primary PM2.5, sulfur dioxide, nitrogen oxides, carbon monoxide and volatile organic compounds, throughput information sufficient for the DNR to calculate its annual, actual emissions. The reportable air contaminants and applicable reporting levels are listed in Table 1 in ch. NR 438, Wis. Adm. Code.

(af) The owner or operator of a facility shall annually submit to the DNR an emissions inventory for sulfur dioxide, nitrogen oxides, carbon monoxide, volatile organic compounds, primary PM10, primary PM2.5, ammonia, and lead and lead compounds, if the facility meets any of the following:

  1. The facility is a Part 70 major source, as defined under 40 CFR 70.2.
  2. The facility is a nonattainment area major source, as defined under s. NR 408.02(21), Wis. Adm. Code.
  3. The facility has the potential to emit equal to or greater than 100 tons per year of ammonia.
  4. The facility has actual emissions equal to or greater than 0.5 ton per year of lead.

What is the emissions inventory reporting threshold for 1-BP (also known as 1-Bromopropane, N-Bromopropane, Propyl Bromide [CAS # 106-94-5])?

While Table 1 to ch. NR 438, Wis. Adm. Code does not include a reporting level for 1-BP, the department requests, under s. NR 438.03(1)(c), Wis. Adm. Code and s. 285.01(1), Wis. Stats., facilities report any 1-BP emissions.

If a facility normally submits a UTN, but emitted 1-bromopropane in the previous calendar year, would the facility have to submit an emissions inventory instead of a UTN?

Yes, the facility would have to submit an emissions inventory instead of an Under-Thresholds-Notification (UTN) if it emitted 1-BP in the previous calendar year. While Table 1 to ch. NR 438, Wis. Adm. Code does not include a reporting level for 1-BP, the department requests, under s. NR 438.03(1)(c), Wis. Adm. Code and s. 285.01(1), Wis. Stats., that facilities report any 1-BP emissions.

Review the facility's Safety Data Sheets (SDS) to determine whether the facility uses 1-BP. If the facility emitted 1-BP in the previous calendar year, submit an emissions inventory as opposed to a UTN.

Why is the Submit Data button inactive?

The Submit Data button will only become active after the following steps are completed:

  1. Update Facility Information
  2. Update Contacts
  3. Run Emissions Calculator
  4. Review and respond to QA Flags
  5. Checkboxes for having reviewed Estimated Fees and the Draft Report

Note: The checkboxes will not become active until items 1 through 4 are [COMPLETE].

Who is required to submit a UTN?

Any facility that is below all reporting thresholds in ch. NR 438, Wis. Adm. Code, is not otherwise required to submit an EI (see above FAQ), and has or needs a registration operation permit (ROP) is required to submit a UTN. However, the DNR strongly encourages every facility that is below reporting thresholds, and is not otherwise required to submit an EI, to submit a UTN to confirm that an emissions review has been conducted and contact information is current.

Why is there not a UTN option for this facility in ARS?

A UTN may only be submitted if the source is below all applicable reporting thresholds and is not otherwise required to submit an emissions inventory under ch. NR 438, Wis. Adm. Code.

The following sources must submit an annual emissions inventory of all criteria air pollutants and ammonia, regardless of actual emissions amounts, and are not eligible to submit a UTN:

  • major sources in nonattainment areas
  • sources with the potential to emit equal to or greater than 100 tons per year of criteria air pollutants or ammonia
  • sources with actual emissions of 0.5 ton per year of lead

Why is the Create UTN button inactive in the Air Reporting System (ARS)?

Before an Under-Thresholds-Notification (UTN) can be created, the Update Facility Information and Update Contacts sections must be completed and saved or marked complete in ARS. For comprehensive directions on how to review/revise contact data, visit the Update Contacts Instructions.

Who is required to certify an EI or submit a UTN?

Every facility that either has or needs a permit or emits NOx or VOC above reporting levels in an ozone nonattainment area must either certify an emissions inventory or, if appropriate, submit a UTN instead of an emissions inventory and certification.

Why are UTNs not certifiable?

UTNs are submitted instead of an EI and EI certification.

Why is the Create Certification button inactive in ARS?

All of the following must be done for the Create Certification button to become active:

  1. the steps indicated on the Submit Data tab (Update Facility Information, Update Contacts, Run Emissions Calculator, Review and respond to QA Flags, ARS Not Already Submitted, and UTN Not Already Submitted) must be marked [COMPLETE]
  2. the two boxes confirming Estimated Fees were viewed and Draft Report reviewed must be checked
  3. the Submit Data button must have been clicked

How is a two-week submittal extension (until March 15 for an EI or UTN) requested?

EI submittal extensions will not be granted via email.

Starting in calendar year 2023 for data year 2022, EI submittal extensions from March 1 to March 15 must be requested directly in the Air Reporting System (ARS).

To request an extension from March 1 to March 15, follow these steps:

  1. log in to ARS
  2. click Review QA Flags/Draft Report/Estimated Fees/Submit Data/Final Report/Certification/Submit Data Extension Request
  3. click on the Submittal Extension Request tab
  4. click Request Extension
  5. the extension will automatically be approved via email

The EI Certification due date of June 30 may not be extended. UTN submittals do not require separate certification.

How is a device and/or process deleted in ARS?

Devices cannot be deleted, but they can be end-dated. To end-date a device and/or process in ARS, email the facility ID (nine-digit number), device/process ID and end date (the date the device/process should be deleted) to either:

How is a North American Industry Classification System (NAICS) code changed?

To change a NAICS code, email DNRAMEmissionsInventory@wisconsin.gov the following information:

  • the facility's identification number (FID)
  • the facility's name
  • the new NAICS code
  • the start date for the new code

How are the air contacts changed (i.e., facility air management contact, facility billing contact, facility air permit contact and responsible corporate official)?

Follow the Update Contacts Instructions.

If contact changes are not working in ARS, or to change the facility contact to a new person, follow the directions on the Notifying The Program About Administrative Facility Changes page.

 

How are the air submittal contacts changed or roles granted (i.e., air compliance submittal, air emission inventory submittal and air permit action submittal)?

See Credentials and Access presentation for detailed directions with screenshots.

How can facilities override automatically populated emission factors?

Emission factors automatically brought into ARS are a starting point, should be reviewed, and may require adjustment to accurately reflect the facility's processes and emissions.

There is the ability to update emission factors in ARS:

  1. Click on the relevant emissions unit in the listed devices
  2. Click on the EmisFactor tab
  3. Click the checkbox for the relevant row in the Select column
  4. Make the correction to the Factor by entering the appropriate value
  5. Select the appropriate throughput unit (TPUnit) and Origin for the new emission factor
  6. Enter a Comment for the basis of the emission factor update so the department understands the basis for the change
  7. Click SAVE ALL when done

If a facility performed a PM stack test, can this same emission factor be used for PM10 and PM2.5?

Yes, the same emission factor can be used for PM, PM10 and PM2.5 because that is a conservative assumption for PM10 and PM2.5 actual emissions.

What emissions units will be required to report PM2.5?

An emissions unit with a listed Source Classification Codes (SCCs) requires PM2.5 reporting, per AM528:

How is a control efficiency added and revised in ARS?

See Adding and Revising Controlling Devices and Processes tutorial for detailed directions with screenshots.

Why is a selected device or process missing?

It is likely that an end date was inadvertently added. Email information about the missing device and/or process to either:

Can device or process IDs be changed?

No. Once a device or process is created, its ID is created and cannot be changed. However, a device and/or process can be end-dated and then recreated under another ID if necessary.

How is a facility's name changed?

To change a facility's name, follow the directions on the Notifying the Air Program About Administrative Facility Changes page.

How is a permit revoked?

To revoke an air permit, follow the directions on the Notifying the Air Program About Facility Closingspage.

How is a permit application withdrawn?

To withdraw a permit application, the facility’s responsible official (person legally responsible for the operation of the permitted air pollution source [see NR 400.02(136), Wis. Adm. Code]) must submit a written request to DNR by email or letter. This request should be sent to:

  • DNRAMAIRPERMIT@wisconsin.gov
    - or -
  • Wisconsin Department of Natural Resources
    Air Program, AM/7
    Attention: Permits
    PO Box 7921
    Madison WI 53707-7921

How does a facility correct a mistake in a submitted EI, either the most recent or from previous years?

Email the DNR the exact corrections that need to be made. One way to do this would be to mark up the draft report or final report and email the redlined version to the appropriate person, which is either:

If it is before March 15 and the edits are for the EI year currently due, the DNR may opt to un-submit the EI and have the facility make the changes instead.

If it is not before March 15 and/or the changes are not for the current EI year, ARS will not be reopened. The DNR will make necessary changes.

Does an air spill (not reported as a permit deviation but reported to the NRC) need to be included in the EI?

Emissions from air spills do need to be included in determining whether a facility is required to submit an emissions inventory under ch. NR 438, Wis. Adm. Code. If a reporting threshold has been exceeded or the facility is otherwise required to submit an emissions inventory under ch. NR 438, Wis. Adm. Code then the emissions from the air spill(s) are required to be included in the submitted emissions inventory.