On July 14, 2015, the U.S. Environmental Protection Agency’s (U.S. EPA’s) Office of Air Quality Planning and Standards’ (OAQPS) Air Quality Modeling Group provided a pre-Federal Register (FR) publication of the proposed revisions to the Guideline on Air Quality Models (Appendix W to 40 CFR Part 51) (Guideline) on the U.S. EPA’s Support Center for Regulatory Atmospheric Modeling (SCRAM) website. In addition, a fact sheet summarizing the revisions made to the Guideline was also provided. As previously announced on SCRAM, the 11th Conference on Air Quality Models (Modeling Conference) is scheduled for August 12 and 13, 2015 at U.S. EPA’s Campus in Research Triangle Park, NC. The Modeling Conference will serve as a public hearing for the Guideline’s revisions, which I will be attending. Written comments will be accepted for 90 days after the final publication in the FR.
Below, I have outlined the revisions to the Guideline that have the biggest impacts on the regulated community. First, it should be noted that the revisions propose a one (1) year transition period during which time previous guidance contained in the 2005 version of the Guideline will be accepted. The Guideline is currently scheduled to be finalized in spring of 2016, allowing U.S. EPA time to address comments received during the 90-day comment period and Modeling Conference public hearing.