UNITEDSTATESENVIRONMENTALPROTECTIONAGENCYREGION5192014TheHonorableMarkDaytonGovernorofMinnesota116VcteransServiceBuilding20West12thStreetSt.Paul,Minnesota55155DearGovernorDayton:77WESTJACKSONBOULEVARDCHICAGO,IL60604-3590REPLYTOTHEATTENTIONOF:ThankyouforyourrecommendationsdatedDecember6,2013,ofairqualitydesignationsforthe2012revisedprimaryannualfineparticle(PM2.s)NationalAmbientAirQualityStandard(NAAQS)throughoutMinnesota.IappreciatetheinformationMinnesotasharedwiththeU.S.Envirmm1entalProtectionAgencyaswemoveforwardtoimprovePM2.sairquality.Thisletteristonotify youofEPA'sintendedresponse toMinnesota'srecommendationsandtoinformyouofourapproachforcompletingtheinitialareadesignationsforthe2012revisedprimaryannualPM2.sstandard.OnDecember14,2012,EPApromulgatedarevisedprimaryannualPM2.sNAAQS(78FR3086,.Tanuary15,2013).Inthataction,EPArevisedtheprimaryannualPM2.:istandard,strengtheningitfrom15.0microgramspercubicmeter(J..Lg/m3)to12.0J..Lg/m3;retainedtheexisting24-hourPM2.sstandardat35flg/m3;retainedtheexisting24-hourPM10(coarseparticle)standardat150J..Lg/m3;andretainedthecurrentsuiteofsecondaryPMstandards.EPArevisedtheprimaryannualPM2.sstandardbasedonanintegratedassessmentofanextensivebodyofnewscientificevidence,whichsubstantiallystrengthensourbodyofknowledgeregardingPM2.s-relatedhealtheffects.TherevisedprimaryannualPM2.sstandardwillprovideincreasedprotectionforchildren,olderadults,personswithpre-existingheartandlungdisease,andotherat-riskpopulationsagainstanarrayofPM2.s-relatedadversehealtheffects,includingprematuremortality,increasedhospitaladmissionsandemergencydepartmentvisits,anddevelopmentandexacerbationofchronicrespiratorydisease.Historyshowsusthatbetterhealthandcleanerairgohand-in-handwitheconomicgrowth.Workingcloselywiththestatesandtribes,EPAisimplementingthestandardsusingacommonsenseapproachthatimprovesairqualityandminimizestheburdenonstate,local,andtribalgovernments.Aspartofthisroutineprocess,EPAisworkingwiththestatesandtribestoidentifyareasinthecountrythatmeetthestandardsandthosethatneedtotakestepstoreducePM2.sairpollution.Within oneyearofpromulgatinganeworrevisedairqualitystandard,theCleanAirActrequirestheGovernorofeachstatetosubmittoEPAalistofallareasinthestate,withadesignationrecommendationforeacharea.Asafirststepinimplementingthe2012armualPM2.sstandard,Governorsweretosubmittheirdesignationrecommendations,includingappropriateareaboundaries,byDecember13,2013.Recycled/Recyclable•PrintedwithVegetableOilBasedInkson100%RecycledPaper(100%Post-Consumer)AsrequiredbytheCleanAirAct,EPAthenpromulgatesdesignationsforallareasacrossthecountry.EPAdesignatesanareaas"nonattainrnent"ifitisviolatingthe2012annualPM2.sNAAQSorifitiscontributingtoaviolationoftheNAAQSinanearbyarea.ConsistentwithdesignationsforpreviousPM2.sstandards,EPAintendstouseadesignationcategoryof"unclassifiable/attainment"forareasthataremonitoringattainmentordonothavemonitors,butforwhichEPAhasreasontobelievearelikelyattainmentandarenotcontributingtonearbyviolations.Additionally,EPAintendstodesignateas"unclassifiable"thoseareaswhereEPAcannotdeterminebasedonavailableinformationwhethertheareaismeetingtheNAAQSorwhereEPAhasnotdeterminedthattheareacontributestoanearbyviolation.Atthistime,EPAisproceedingwithintendedinitialareadesignationsusingquality-assured,certifiedairqualitymonitoringdatafrom2011to2013.EPAhasreviewedMinnesota'sDecember6,2013,annualPM2.sdesignationrecommendationsandotherrelevanttechnicalinformation,including2011-2013airqualitydata.Thesedatadonotindicateanyviolationofthe2012annualPM2.sNAAQSinMinnesotaorcontributiontoanynearbyarea.Accordingly,EPAintendstodesignatetheentirestateofMinnesotaasunclassifiable/attainment.EPAwillmakeitsproposeddesignationdecisionsandsupportingdocumentationavailabletothegeneralpublicforreviewandcomment.Wewillbeannouncinga30-daypubliccommentperiodshortlyintheFederalRegister.Afterconsideringtheadditionalinformationwereceive,EPAplanstopromulgatefinalarmualPM2.sdesignationsinDecemberof2014.EPAiscommittedtoworkingwiththestatesandtribestosharetheresponsibilityofreducingPM2.sairpollution.Currentandupcomingfederalstandardsandsafeguards-includingpollutionreductionrulesforpowerplants,vehicles,andfuels-willensuresteadyprogresstoreducePM2.5-formingpollutionandwillprotectpublichealthincommunitiesacrossthecountry.Welookforwardtoacontinueddialoguewithyouandyourstaffasweworktogethertoimplementthe2012annualPM2.sstandard.Ifyouanyquestions,pleasecontactmeoryourstaffmaycontactRonnaBeckmannorEileenDeamer,theRegion5IntergovernmentalLiaisons,at(312)886-3000.Sincerely,SusanHedmanRegionalAdministratorcc:JohnLineStineCommissionerMinnesotaPollutionControlAgencyDavidThorntonAssistantCommissionerMinnesotaPollutionControlAgency