On April 15, 2017, the Arizona Department of Environmental Quality (ADEQ) released updates to the Air Quality Modeling Guidelines for Arizona Air Quality Permits (the ADEQ Guidelines). The ADEQ Guidelines were last updated on December 1, 2015 and are used to help air permit applicants understand air quality modeling procedures for sources located in Arizona under ADEQ jurisdiction.

The ADEQ Guidelines were updated to address public comments related to the minor New Source Review (NSR) program and the recent Environmental Protection Agency (EPA) updates to the federal dispersion modeling guidelines. Modifications to key air quality modeling concepts contained in the ADEQ Guidelines include the following:

  • Removed CALPUFF as a preferred model for long-range transport and designated it as a "screening technique."
  • Added the ability to use prognostic meteorological data if representative national weather station (NWS) data are not available.
  • Added a new modeling demonstration option for nonattainment pollutants.
  • Updated nitrogen dioxide (NO2) modeling methodologies.
  • Modified modeling requirements for secondary particulate matter with diameter less than 2.5 (PM2.5).
  • Created a new section to address ozone (O3) modeling requirements.