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Regulatory Update

EPA Proposes Changes to Air Emissions Reporting Requirements (AERR)

August 30, 2023

The EPA is proposing updates to their Air Emissions Reporting Requirements (AERR) through amendments to 40 CFR Parts 2 and 51. The proposed regulation was published in the Federal Register on August 9, 2023 [2023-16158.pdf (]. The AERR is the mechanism by which state/local/certain tribal agencies (agencies) inventory and report actual emissions of criteria air pollutants and precursors (CAPs) collected from regulated emissions sources. The EPA cites the need to improve their collection of CAPs and to add the collection of hazardous air pollutant (HAP) actual emissions data, defaulting to AERR reporting directly by individual facilities unless their State Agencies agree to do so. This change by EPA is to ensure they have sufficient information to identify and solve potential air quality and exposure problems and ensure that communities have the data needed to understand the potential for significant environmental risks or impacts to regional air quality.


The EPA identified three main reasons for the proposed amendments within the preamble:

  1. Ensure they have sufficient information to identify and solve air quality and exposure problems.
  2. Allow the EPA to have information readily available that the Agency needs to protect public health and perform other activities under the Clean Air Act.
  3. Safeguard that communities have the data needed to understand significant sources of air pollution that may be impacting them, including potent carcinogens and other highly toxic chemicals linked with a wide range of chronic and acute health problems.

Proposed Changes

Under the current AERR, agencies are required to report actual CAP emissions to the EPA with the option to report HAP emissions and other pollutants from point sources (typically Title V sources), nonpoint sources (collective of small and difficult to inventory sources), on-road and nonroad mobile sources, and an option to report air quality impacts from wildfires and prescribed fires. The reporting is based on threshold triggers listed in 40 CFR Part 51 with every third year (“Triennial Inventory”) having lower reporting thresholds.

The proposed changes are expected to take effect starting with Reporting Year 2026, and include:

  • Add HAP emissions to annual reporting.
  • Lower the annual emissions thresholds to the triennial levels for each year starting in 2027.
  • Include prescribed fire data.
  • Add requirements for reporting fuel data for certain sources of electrical generation associated with peak electricity demand, likely small generating units operating to offset or meet peak electricity demand.
  • Prescribe that information collected through the AERR is public (not subject to confidential treatment).
  • Include additional requirements for point source facilities as follows:
    • Report HAP emissions directly to the EPA through the Combined Air Emissions Reporting System (CAERS) unless the EPA approves the state/tribal agency’s process and if that agency accepts the reporting responsibility.
    • Report performance test data and performance evaluation data by facilities meeting certain criteria.
    • Identify all federally enforceable regulations that apply to each unit at certain facilities for the purpose of providing a repository documenting the regulations a facility has determined apply to its units.
    • Title V Permit numbers for major sources.
    • Report a summed activity level for fuel use from combustion sources.
    • Location information (i.e., latitude and longitude) for stack and fugitive release points, which has previously been voluntary.

PFAS too?

The EPA is considering whether this action should include reporting of per-and polyfluoroalkyl substances (PFAS) while acknowledging their limitations in their understanding of PFAS. They are seeking comments on how they could include PFAS reporting requirements in the final action.

Public Hearing

A virtual public hearing was scheduled for August 30, 2023 by the EPA to allow pre-registered commentors to provide oral testimony on the proposed rule. They will announce any further details through their site (Air Emissions Reporting Requirements (AERR) | US EPA).

The EPA is reopening the comment period for the Information Collection Request (ICR) number 2170.09, for the proposed Air Emissions Reporting Requirements (AERR), published in the Federal Register on August 9, 2023, extended it to October 18, 2023.

Next Steps: TRC Can Help

TRC has extensive experience with Air Toxics emission testing and estimation, air dispersion modeling of air toxics and prediction of ambient concentrations, human health risk assessment and impacts mitigation. Once HAP emissions are reported directly to EPA and made public, EPA and affected communities will want to understand any potential for adverse impacts to local air quality. TRC has been performing these evaluations for years and can assist your facility with understanding potential air quality impacts before the AERR reporting requirements kick in. We can assist in reviewing procedures for data collection and emissions reporting directly via AERR and provide suggested methods to ensure compliance if this proposed rule is promulgated. TRC also has leading PFAS experts who can answer your questions about the new and evolving regulations and requirements.

Contact emissions experts Bob Fraser at and Chris Howard at to discuss what standards may be applicable to your facility.

Looking for effective solutions to your problems?

Turn to the experts at TRC.

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