Air Plan Revisions; California; Mojave Desert Air Quality Management District; Oxides of Nitrogen

The Environmental Protection Agency (EPA) is finalizing a limited approval and limited disapproval a revision to the Mojave Desert Air Quality Management District (MDAQMD) portion of the California State Implementation Plan (SIP). This revision concerns emissions of oxides of nitrogen (NO<INF>X</INF>) from industrial, institutional, and commercial boilers, steam generators, and process heaters. We are finalizing a limited approval of a local rule that regulates these emission sources under the authority of the Clean Air Act (CAA or the Act), because the rule would strengthen the current SIP-approved version of MDAQMD's rule for boilers and process heaters. We are finalizing a limited disapproval of this revision because it is inconsistent with the EPA's startup, shutdown, and malfunction (SSM) policy and Credible Evidence Rules.