On September 11, 2018, the United States Environmental Protection Agency (EPA) signed the Regional Haze Reform Roadmap, which directs EPA staff to take certain actions to ensure adequate support for states to enable timely and effective implementation of the regional haze program today and in the future. The EPA will provide tools and guidance to states throughout the next year as they develop their second planning period State Implementation Plans (SIPs).

During the Arizona Department of Environmental Quality (ADEQ) Regional Haze SIP kickoff meeting at the beginning of October, the following was determined:

  • Arizona will develop a common methodology for Source Screening which will be consistent with the rest of the member states of the Western Regional Air Partnership (WRAP)
  • 2014 will be the regional haze base year (for emission inventory review) with a projection to 2028
  • Baseline conditions (which are used to perform Source Screening) will be reset every 10 years
  • Analyses will be completed by WRAP with the utilization of CMAQ and CAMx on a 12 km grid
  • CALPUFF may not be used unless Arizona authorizes the use
  • Under reasonable progress approach ANY source may be subject to Best Available Retrofit Technologies (BART) including mobile sources
  • Impacts at Class I areas in adjacent states will be reviewed
  • Aspects of the EPA's January 2017 Regional Haze Rule will be revisited to address provisions and other elements of the rule

The Implementation schedule is as follows:

  • Final recommendations for determining natural visibility conditions and selecting the 20 percent most impaired days to track visibility conditions will be accepted in the Fall of 2018
  • ADEQ plans to have an initial estimate of sources subject to Regional Haze in February of 2019
  • Natural visibility conditions estimates will be updated, as necessary, in the Spring of 2019
  • The Office of Air and Radiation (OAR) will issue a new, updated version of the Guidance Document on Regional Haze SIP Development in the Spring of 2019
  • The visibility modeling platform and documentation and results including United States and international source contributions for Class I areas will be updated to 2028 by the Summer of 2019