Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Approval of the Base Year Emissions Inventory for the Liberty-Clairton Nonattainment Area for the 2006 24-Hour Fine Particulate Matter Standard and Approval of Transportation Conformity Insignificance Findings for the 1997 Annual and 2006 24-Hour Fine Particulate Matter Standards for the Liberty-Clairton Nonattainment Area

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The Environmental Protection Agency (EPA) proposes to approve the State Implementation Plan (SIP) revision submitted by the Commonwealth of Pennsylvania for the purpose of meeting the statutory emissions inventory requirements for the Liberty-Clairton nonattainment area (hereafter "the Liberty-Clairton Area" or "the Area") with respect the 2006 24-hour fine particulate matter (PM 2.5 ) National Ambient Air Quality Standard (NAAQS or standard). The SIP revision consists of the 2007 base year emissions inventory for the Liberty-Clairton Area for the 2006 24-hour PM 2.5 NAAQS. EPA is also proposing to approve a SIP revision consisting of Pennsylvania's determinations for both the 1997 annual and 2006 24-hour PM 2.5 standards that onroad emissions of PM 2.5 and nitrogen oxides (NO X ) are insignificant contributors to PM 2.5 concentrations in the Liberty-Clairton Area for transportation conformity purposes. In the Final Rules section of this Federal Register, EPA is approving Pennsylvania's SIP submittal as a direct final rule without prior proposal because the Agency views this as a noncontroversial submittal and anticipates no adverse comments. The publication of this document starts