Partial Approval and Disapproval of Air Quality Implementation Plans; Arizona; Regional Haze State Implementation Plan for the Second Implementation Period and Prong 4 (Visibility) for the 2015 Ozone and 2012 Particulate Matter Standards

The Environmental Protection Agency (EPA) is partially approving and partially disapproving the regional haze state implementation plan (SIP) revision submitted by Arizona on August 15, 2022 ("2022 Arizona Regional Haze Plan"), under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. Arizona's SIP submission was developed to address the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. Within this action, the EPA is also disapproving the visibility transport prong of Arizona's infrastructure SIP submittals for the 2012 annual fine particulate matter (PM<INF>2.5</INF>) and 2015 ozone National Ambient Air Quality Standards (NAAQS). The EPA is taking this action pursuant to CAA sections 110 and 169A.