Pursuant to the Federal Clean Air Act (CAA or the Act), the Environmental Protection Agency (EPA) is approving a revision to a State Implementation Plan (SIP) submitted by the Secretary of the Louisiana Department of Environmental Quality (LDEQ) on March 25, 2021. The SIP submittal addresses requirements of Federal regulations that direct the State to submit a periodic report that assesses progress toward regional haze reasonable progress goals (RPGs) and includes a determination of adequacy of the existing implementation plan.

The Environmental Protection Agency (EPA) is approving a state implementation plan (SIP) revision submitted by the State of Maryland. This revision provides Maryland's determination, via a negative declaration, that there are no sources within its borders subject to EPA's 2016 Oil and Natural Gas control techniques guidelines (2016 Oil and Gas CTG). EPA is approving these revisions to the Maryland SIP in accordance with the requirements of the Clean Air Act (CAA).

The Environmental Protection Agency (EPA) is approving revisions to the Iowa State Implementation Plan (SIP) to include changes to the Polk County Board of Health Rules and Regulations in addition to revisions from past submittals. The revisions update definitions and references to the effective dates of Federal rules approved into the State's SIP, prohibit burning of demolished buildings, update references to methods and procedures for performance test/stack test and continuous monitoring systems, and revise permitting exemptions.

The Environmental Protection Agency (EPA) is finalizing a limited approval and limited disapproval of a revision to the Mojave Desert Air Quality Management District's (MDAQMD or District) portion of the California State Implementation Plan (SIP). This revision concerns oxides of nitrogen (NO<INF>X</INF>) emissions from stationary internal combustion engines.