SO2 Data Requirements Rule: State Pathway Notifications

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The SO2 Data Requirements Rule (DRR) required agencies to notify EPA of their selected approach, or "pathway," for characterizing air quality around each SO2 source subject the DRR by July 1, 2016. The DRR provided air agencies with the following four pathways:

  • submit air quality modeling;
  • conduct air quality monitoring;
  • adopt federally enforceable emission limits for a source to reduce emissions below 2,000 tpy, unless further air quality characterization is required in the judgment of the air agency or EPA; or,
  • submit documentation that a source has permanently shut down by January 13, 2017;

Below are links to state submittals to meet the DRR pathway notification requirement and EPA response documents. In some cases, in addition to the pathway notification letters, the files below may include modeling protocols, monitoring plans or other information submitted by the state.

The "DRR Source List with Pathway Notification and State Submittal" file is a summary table of state submittals to meet the DRR pathway notification requirement and modeling, monitoring, emissions limit, and shut down information submitted by the states prior to January 13, 2017. This table was originally posted in September 2016 and has been updated to reflect materials submitted to EPA  as of March 2017. 

For questions concerning a state’s pathway notification submittal, please contact the respective EPA regional office. Contact information is available in the "EPA SO2 Regional Modeling Contacts" file below.

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Last updated on April 3, 2025