USEPA is approving a June 1, 1999 request from Ohio for a State Implementation Plan (SIP) revision of the Dayton/Springfield, Ohio ozone maintenance plan. The maintenance plan revision establishes a new transportation conformity mobile source emissions budget for the year 2005. We are also approving the revision of the maintenance plan which reestimates point source growth and allots a larger volatile organic compounds (VOCs) budget to the area's 2005 mobile source sector for transportation conformity purposes. This allocation will still maintain the total emissions for the area at or below the attainment level required by the transportation conformity regulations. We are also correcting a typographical error in the original maintenance plan approval.