Air Plan Approval; Michigan; Finding of Failure To Attain the 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard for the Detroit Nonattainment Area

The Environmental Protection Agency (EPA) is determining that the Detroit sulfur dioxide (SO<INF>2</INF>) nonattainment area failed to attain the 2010 primary 1-hour SO<INF>2</INF> national ambient air quality standard (NAAQS or "standard") by the applicable attainment date of October 4, 2018. This determination is based upon air quality modeling using actual and allowable emissions. This action requires the State of Michigan to submit one year after date of publication in the Federal Register a revision to its State Implementation Plan (SIP) that, among other elements, provides for expeditious attainment of the 2010 SO<INF>2</INF> standard. EPA is not finalizing the finding of failure to attain for the Rhinelander, Wisconsin area that was included in the notice of proposed rulemaking (NPRM), as a finding of failure to attain only applies to nonattainment areas and EPA expects to redesignate the area to attainment before the effective date of this action.