Updates to the Guideline on Air Quality Models: A New Chapter

• By: AWMA
• On: 10/02/2024 09:34:10
• In: EM Articles
• Comments: 0

by Anthony J. Schroeder

Air dispersion modelers in the United States and around the world rely on the guidance contained in the U.S. Environmental Protection Agency's (EPA) Guideline on Air Quality Models, which is codified at 40 CFR 51, Appendix W. This guidance document, originally published in 1978, has been modified occasionally over the years as advances have been made in dispersion modeling theory and as new standards have been promulgated that have required the use of new and innovative modeling techniques.

The most recent revisions to the Guideline were proposed and published in the Federal Register in October 2023. Along with the proposed revisions, EPA released an updated version of the AERMOD Model (and associated pre-processor programs, such as AERMET) that incorporated options that EPA proposed to add as regulatory default options. EPA took comments on the proposed revisions in late 2023 and has been working toward responding to comments and issuing a final revised version since then. A final version of the Guideline on Air Quality Models and new versions of AERMOD and associated programs are expected to be released in fall 2024, as of the time of writing this article.

The articles included in this issue of EM cover the most significant updates that EPA proposed to the Guideline and the AERMOD Model in their October 2023 proposal.

Continue reading the full October 2024 issue of EM.