On June 5, 2017, the Office of Inspector General (OIG) for the EPA sent a memorandum to EPA's Office of Air and Radiation indicating the OIG will begin research into EPA's review and approval process for air quality dispersion models concentrating on the Office of Air Quality Planning and Standards (OAQPS). Specifically, the OIG will focus its review on AERMOD and will ultimately determine whether AERMOD has been adequately evaluated for its intended applications in the regulatory framework of the Clean Air Act. So far OIG has requested all model evaluations, all peer reviews, and all consequence analyses of AERMOD and has requested a kickoff meeting with EPA's Office of Air and Radiation.
The OIG originally announced its intent to investigate EPA's air quality model approval process in the OIG's 2017 Fiscal Year - Annual Plan, which was released in December 2016. Given the investigation has been scheduled since late 2016, its origin is likely not associated with the new administration. Instead the investigation likely originated from the scrutinizing of Appendix W in its latest revision (published in January 2017) by the Office of Management and Budget (OMB). The review of the latest Appendix W revision was necessitated by an October 1993 Executive Order 12866, requiring the determination of whether Appendix W could potentially interfere with another action taken or planned by another agency. The impact the current administration will have and the importance which will be placed on the OIG investigation is still yet to be seen, but if prior investigations are comparable indicators, it is expected that OIG will publish a final report in 12 to 18 months. The report is expected to provide all of the findings and results of the audit, along with recommendations from the OIG to improve the dispersion model approval process. OIG semiannual and issue specific reports are made available on the OIG website along with audio recordings of report overviews and other relevant information.
The OIG investigation is still in the preliminary stages of its review and is expected to take at least one full year for completion. In the meantime, the regulated community will likely receive updates through the OIG semiannual reports and through public discussion platforms. An Air & Waste Management Association specialty conference is currently scheduled for November 14th - 16th, which will feature a discussion panel with OAQPS officials. It is expected that the OAQPS personnel will provide an update and reflect on possible outcomes of the investigation during this meeting. The general consensus among regulators at this point in time seems to indicate EPA's model review and approval process (and Appendix W overall) will remain largely intact and only receive minor enhancement suggestions after the investigation is closed. Regardless, in the past OIG investigations have been cause of major changes within EPA and whether this review of AERMOD's approval will yield any significant alterations to air dispersion modeling practices is still to be decided.