Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Motor Vehicle Inspection and Maintenance Program-Revised Final Standards for the Acceleration Simulation Mode Exhaust Emissions Test

EPA is approving a State Implementation Plan (SIP) revision submitted by the Commonwealth of Pennsylvania. This revision amends Pennsylvania's SIP-approved Enhanced Vehicle Inspection and Maintenance Program (or I/M program) to implement final tailpipe test standards for the Acceleration Simulation Mode (ASM) tailpipe emissions test. This is being done through the substitution of revised ASM test standards in place of the previously adopted and SIP-approved final ASM test standards. Under Pennsylvania's SIP-approved I/M program, ASM testing is conducted only in the Philadelphia I/M program area comprised of Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties. Therefore, this action affects only motorists in those counties subject to the ASM test as part of the I/M program for the Philadelphia area. The intended effect of this action is to approve Pennsylvania's SIP revision request. This action is being taken under authority of the Clean Air Act.