tUNITED STATES ENVIRONMENTALPROTECTIONAGENCYREGIONIll1650ArchStreet-Philadelphia, Pennsylvania 19103-2029HonorableJohn Hanger,Acting SecretaryPennsylvania DepartmentofEnvironmentalProtectionRachel CarsonState OfficeBuilding, 16thFloor400MarketStreetHarrisburg,Pennsylvania 17101-2301Dear SecretaryHanger:OnMarch12,2008,theU.S.Environmental ProtectionAgency(EPA) revised thenational ambientair quality standards(NAAQS)for ozonetoprovideincreased protectionofpublichealthandwelfare fiom ozone pollution. Thenewprimary ozonestandard wasloweredfiom 0.08 partspermillion(ppm) to0.075ppm basedonnumerous epidemiological studiesconducted duringthe past decade in which manyofthehealtheffectsassociated with ozoneexposure have beendemonstratedat andbelowthelevelof the 0.08ppmstandard, which waspromulgatedin1997. These includearangeofseriousrespiratoryeffectsandincreasedprematuremortality.EPAalsostrengthenedthe secondary 8-hour ozonestandard, makingitidenticaltotherevisedprimarystandard, to protect against welfareeffects suchasimpactsonvegetationandforested ecosystems.WithinoneyearofpromulgationofaneworrevisedNAAQS,section1O7(d)(l)(A)oftheClean AirActrequires theGovernorof each stateto submit to EPA alist ofall areasinthestate, recommendingdesignations for each as"attainment," "nonattainment,"or"unclassifiable"withrespect tothe neworrevisedstandard. Therefore,EPAasks thatyouprovideyourdesignationrecommendations, including appropriatearea boundaries,toEPAbyMarch12,2009with respect totherevisedozoneNAAQS.Establishingarea designationsisakeystepintheprocessofproviding the health protectionsthattheCleanAirActmandates.rea asthat aredesignatedasnotattaining the air quality standardswillberequired to adoptplansto reduceambient concentrationsofozone.Theenclosed memorandum provides guidance tostateandlocal airpollutioncontrolagenciesandTribesontheprocessfor designating areas under the2008 revisedozonestandard.EPAplansto announceourintendeddesignations as early as possibleafterreceipt ofyourrecommendations,butnolaterthan120 days priortopromulgating final designations.Followingtheannouncementofintendeddesignations, statesandTribeswillhave the'opportunityto commentonany modificationsEPAproposes totheirrecommendations.Inaccordance withsection107(d)(l)(B)of theClean Air Act,weintend toissuefinal designationsbyMarch12,2010 (although thatdeadline maybeextended upto oneadditionalyearifEPAdetermines thatinsufficient information is availabletoestablish designations bythat date). Ourdesignations willbebasedonthemostrecent threeyearsofcertified,qualityassured monitoringdataavailable.Ozone nonattainment areaswillbeclassifiedatthe timeofdesignation. TheapproachEPAwillusetoclassifynonattainment areas underthe2008 revisedozoneNAAQSwillbeestablished through aseparatenotice-and-commentrulemaking.EPAlooksforward to working with youand yourstaff todevelop area designationsunderthe2008revised ozonestandardsinatimelymanner. Asalways, please feelfreetocontactmeorMs.JudithKatz, RegionII17sAir ProtectionDivisionDirector, at215-814-2654ifadditionalinformation isneeded.Sincerely,Is1DonaldS.WelshRegional AdministratorEnclosurecc:Ms.JoyceE. Epps, Director, BureauofAirQualityPennsylvania DepartmentofEnvironmental Protection