On November 6, 2020, the Environmental Protection Agency (EPA) published a notice of proposed rulemaking to approve redesignation of the Salt Lake City, Utah and Provo, Utah nonattainment areas (NAAs) to attainment for the 2006 24-hour fine particulate matter with an aerodynamic diameter less than or equal to a nominal 2.5 microns (PM<INF>2.5</INF>) National Ambient Air Quality Standard (NAAQS), and also acted on multiple related State Implementation Plan (SIP) submissions.