Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Diesel-Powered Motor Vehicle Idling Act

EPA is taking direct final action to approve a revision to the Pennsylvania State Implementation Plan (SIP). The revision consists of the Commonwealth's Diesel-Powered Motor Vehicle Idling Act (hereafter referred to as the Diesel-Powered Motor Vehicle Idling Act or as Act 124 of 2008, or simply Act 124). Act 124, passed by the Pennsylvania General Assembly and signed into state law by Governor Rendell in October 2008 (and effective at the state level in February 2009), reduces the allowable time that heavy-duty, commercial highway diesel vehicles of over 10,000 pounds gross vehicle weight can idle their main propulsion engines. The law restricts idling of these commercial diesel vehicles (mostly heavy trucks and buses) to a period of 5 minutes per continuous 60 minute period (with certain allowable exemptions and exclusions). Act 124 applies statewide in the Commonwealth, and is estimated by Pennsylvania to significantly reduce emissions of nitrogen oxides, volatile organic compounds, and fine particulate matter. While idle time emissions limits are not mandatory under the Clean Air Act (CAA), incorporation of Act 124 into the SIP does strengthen the SIP, makes the state law federally enforceable by EPA, and allows the Commonwealth to take credit for emissions benefits from the rule as part of future Pennsylvania SIP revisions to demonstrate compliance with CAA National Ambient Air Quality Standards (NAAQS). EPA is approving this revision governing idling time limits on commercial heavy duty vehicles into the Pennsylvania SIP. This action is not a federal mandate required by the CAA, but provides emission reductions that aid Pennsylvania in complying with CAA NAAQS. EPA's approval of this SIP revision is being done in accordance with the requirements of the CAA.