Approval and Promulgation of Air Quality Implementation Plans; Delaware; MOBILE6-Based Motor Vehicle Emission Budgets for the Delaware Portion of the Philadelphia-Wilmington-Trenton 1-Hour Ozone Nonattainment Area

EPA is taking direct final action to approve a revision to the Delaware State Implementation Plan (SIP). Specifically, EPA is approving amendments to the 2005 highway (on road) motor vehicle emission inventory for the Delaware portion of the Philadelphia- Wilmington-Trenton area's (the Philadelphia area) 1-hour ozone attainment plan as a revision to the Delaware SIP. This revision also serves to amend the 2005 motor vehicle emission budgets (MVEBs) used for determining transportation conformity under the Clean Air Act. The revised MVEBs were developed using MOBILE6, the most recent version of EPA's mobile source emission factor model. Revision of the MVEBs was a requirement of EPA's prior approval of Delaware's 1-hour ozone attainment demonstration plan for the Philadelphia severe ozone nonattainment area. The intended effect of this direct final approval action is to approve a SIP revision that will assist Delaware in attaining and demonstrating conformity with the 1-hour ozone standard. This action is being taken by EPA in accordance with the requirements of the Clean Air Act.