UNITEDSTATESENVIRONMENTALPROTECTIONAGENCYREGIONIII1650ArchStreetPhiladelphia,Pennsylvania19103DATE:NOV222011SUBJECT:TechnicalSupportDocumentRegardingMonitoringData—Delaware,Maryland,NewJersey,andPennsylvania;DeterminationsofAttainmentofthe1997AnnualFineParticulateStandardforthePhiladelphia-WilmingtonNonattainmentAreaFROM:äfaeniorAirQualityPlanningSpecialistOfficeAirProgramPlanning—/46LorettaHden,EnvironmentalEngineerOfficeofAirMonitoring&AnalysisTO:FN(2-1<Y\/f///iTHRU:CristinaFernandez,AssociateDirectorOfficeofAirProgramPlanningThisdocumentprovidesatechnicalreviewoftheairqualitymonitoringdatausedtosupporttheEnvironmentalProtectionAgency’s(EPA’s)proposeddeterminationthatthePhiladelphiaWilmington-AtlanticCity,PA-NJ-DEannualPM25nonattainmentarea(thePhiladelphiaArea)hasattainedthe1997annualPM2.5nationalambientairqualitystandard(NAAQS)byitsstatutoryattainmentdateandEPA’sproposedcleandatadeterminationforthePhiladelphiaArea.I.BACKGROUNDThePhiladelphiaAreaincludestheNewCastleCountyinDelaware;Burlington,Camden,andGloucesterCountiesinNewJersey;andBucks,Chester,Delaware,Montgomery,andPhiladelphiaCountiesinPennsylvania.Theattainmentdateforthe1997annualPM2.5NAAQSisApril5,2010.See40CFR51.1004(a).II.EVALUATIONOFAIRQUALITYMONITORINGDATAA.DataRequirementsThecriteriafordeterminingifanareaisattainingthe1997annualPM2.5NAAQSaresetoutin40CFR50.13andappendixN.TheannualPM2.5NAAQSismetwhentheannualdesignvalueislessthanorequalto15.0microgramspercubicmeter(jig/m3).Threeyearsofvalidannualmeansarerequiredtoproduceavalidannualstandarddesignvalue.Ayearmeetsdatacompletenessrequirementswhenatleast75percentofthescheduledsamplingdaysforeachquarterhavevaliddata.Quarterlydatacapturerates(expressedasapercentage)arespecificallycalculatedasthenumberofcreditablesamplesforthequarterdividedbythenumberofscheduledsamplesforthequarter,theresultthenmultipliedby100androundedtothenearestinteger.TheuseoflessthancompletedataissubjecttotheapprovalofEPA,whichmayconsiderfactorssuchasmonitoringsiteclosures/moves,monitoringdiligence,andnearbyconcentrationsindeterminingwhethertousesuchdata.Thedatamustbecollectedandquality-assuredinaccordancewith40CFRpart58,andmustberecordedinEPA’sAirQualitySystem(AQS).Thedatasupportingattainmentofthestandardmustbecompleteinaccordancewith40CFRpart50,appendixN.B.CertifiedAirQualityMonitoringData,2007-2009and2008-2010TheStatesofDelaware,andNewJersey,andtheCommonwealthofPennsylvania(“theStates”)submittedqualityassuredairqualitymonitoringdataintoAQS.TheStatesthencertifiedthatdata.Whilemostofthemonitoringdataiscomplete,severalmonitorshadcompletenessissues,asdescribedbelowintheDataCompletenessIssuessection.AttachedaretwoAQSreportscontainingannualPM2.5dataforthePhiladelphiaAreafor2007to2009and2008-2010.Tables1and2,below,summarizesthosereports.Notes:MaxQ=sitepassedthemaximumC=completeInc=incomplete*=sitestartedoperatingin2008.TableI2007-2009PhiladelphiakreaAnnualPM2.çDesignValues&DataCompleteness____2007-2009CompleteAnnualMeanDataStateCountySiteIDDesignValueQuarters__200720082009(jig/rn3)200720082009CompleteNewCastle10003100313.413.010.212.2434MaxQDE10003100712.511.510.011.3444MaxQ10003101213.412.510.612.2444C10003200414.413.511.213.0444CNJCamden34007100713.811.99.511.7444CGloucester34015000413.311.59.311.4343MaxQBucks42017001213.012.710.812.2444CChester42029010014.113.714.113.9232IncDelaware42045000214.713.912.413.7444CPAMontgomery42091001313.111.710.411.7444CPhiladelphia42101000413.713.010.812.5444C42101002412.912.09.911.6343MaxQ42101004714.313.511.113.0343MaxQ421010055*13.511.312.4*44C42101005712.013.311.112.1444Cquarterdatasubstitutiontest.2Table2:2008-2010PhiladelphiaAreaAnnualPM2.5DesignValues&DataCompletenessNotes:MaxQsitepassedthemaximumquarterdataC=completeC.EPA’sAnalysisofthe2007-2009and2008-2010PhiladelphiaAreaMonitoringDataEPAhasreviewedtheambientairmonitoringdataforPM25,consistentwiththerequirementscontainedin40CFRpart50andrecordedintheAQSforthePhiladelphiaAreafrom2007through2010.Allmonitorsmeasuredconcentrationsaveragingwellbelowtheannualstandardof15.0ig/m3.Thehighestdesignvalueforthemostrecent3yearperiod,2008-2010,forthePhiladelphiaAreais13.8jig/m3,basedonmonitoringdatacollectedatmonitor420290100inChesterCounty,Pennsylvania,the“NewGarden”monitor.DataCompletenessIssues1)MaximumOuarterDataSubstitutionTestAsshowninTables1and2,severalmonitorsinthePhiladelphiaAreahavelessthan4quartersofcompletedataforoneormoreyearinboththe2007-2009and2008-2010monitoringperiods.Forthesemonitors,EPAappliedthedatasubstitutiontestsetoutintheApril1999EPAguidancedocument“GuidelineonDataHandlingConventionsforthePMNAAQS,”attached.Thistestisusedformonitorswithmissingdata.Maximumrecordedvaluesaresubstitutedforthemissingdata.Theresultingdesignvalueiscomparedtothestandard.Themonitorpassesifthedesignvaluewithmaximumvaluessubstitutedmeetsthestandard.Specifically,thetestrequiresreplacingthemissingdatawiththemaximumconcentrationrecordedatthesiteduringthesamequarteroverthethree-yearperiodinquestion,providedthatthefollowingcriteriaaremet.Thesitemusthavevaliddataforatleast50percentoftheschedulednumberofsamplesfor2008-2010CompleteAnnualMeanDataStateCountySiteIDDesignValueOuarters200820092010(ig/m3)200820092010CompleteDENewCastle10003100313.010.210.211.1344MaxQ10003100711.510.010.010.5434MaxQ10003101212.510.610.411.2444C10003200413.511.210.611.7444CNJCamden34007100711.99.59.510.3444CGloucester34015000411.59.39.110.0443MaxQPABucks42017001212.710.810.511.3444CChester42029010013.714.113.813.8344MaxQDelaware42045000213.912.313.213.3444CMontgomery42091001311.710.49.510.5444CPhiladelphia42101000413.010.810.711.5444C42101002412.09.99.610.5444C42101004713.511.111.011.9444C42101005513.511.311.312.0444C42101005713.311.110.911.7444CInc=incompletesubstitutiontest.3eachquarterforallthreeyears,andtheemissionsandmeteorologyforthequarterstobesubstitutedmustbecomparabletotheemissionsandmeteorologyforthequartersinquestion.ThemonitorsinTables1and2thathave“MaxQ”intheDataCompletecolumnpassedthistest.2)DataCompletenessfortheMonitor420290100,ChesterCounty,PennsylvaniaForMonitor420290100,theNewGardenSite,themaximumquartersubstitutiontestdescribeabovecouldnotbeusedtoshowattainmentforthe2007-2009monitoringperiod.Themonitoratthislocationhadvariousmechanicalissuesandhassincebeenreplacedwithacontinuousmonitorthatismeetingquarterlycompletenessrequirements.InordertodeterminewhethertheNAAQSwasmetforthe2007-2009periodfortheNewGardenmonitor,EPAhasappliedarecentlydevelopedproceduretoaddressthemissingdata.EPA’sprocedureisdescribedinthefollowingsection.AddressingMissingDataEPAdevelopedanobjectivestatisticalmethodtodetermineifmonitorsthatlackcompletedatawouldhavemettheNAAQSinsubsequenttimeperiods.ThefirststepofthestatisticalmethodusedtodeterminewhetheranincompletemonitorwouldhavemettheNAAQSistoestablishalinearregressionrelationshipbetweenthetargetmonitorandanothermonitorinorclosetothenonattainmentarea.Thelinearregressionisthenusedtofillinthemissingdataforthetargetmonitor.Theresultsarecheckedwithanadditionalstatisticaltechnique,knownasbootstrapping,toverifyiftheconclusionofattainmentiscorrect.ThePhiladelphiaAreahas16monitoringlocations,butbecauseoftheuniquesitingandlocalimpactstotheNewGardenmonitor,aPM2.5monitoringsiteinCecilCounty,Marylandwasselectedasthecandidatemonitor.Thismonitorisoutsideofthenon-attainmentarea,butisapproximately10milesawayfromNewGardenwithsimilarsitingandlocalimpacts.ThemonitorofinterestinthisanalysisistheNewGardenmonitor.Thissitehasstruggledwithcompletenessissuessince2006andhasnothadavaliddesignvaluesince2005.SeeFigure1,Attached.Thegoalofthismethodologyistoappropriatelyfillinthemissingdatafrom2007and2008tojudgewhetherthislocationwouldlikelyhavemonitoredattainmentoftheNAAQShadthemonitorhadcompletedata.ConceptfordeterminingdesignvaluesThemethodfordeterminingadesignvalue(DVs)foramonitorwithincompletedata(NewGarden)istoestablishalinearregressionrelationshipbetweenthesitewithincompletedata(NewGarden)andanothersite(CecilCounty)inthevicinityofthenonattainmentareawhichhasmorecompletedataintheperiodinwhichtheincompletesite(NewGarden)isdatadeficient.ThelinearregressionrelationshipisbasedontimeperiodsinwhichboththeNewGardenandCecilCountymonitorswereoperating.ThelinearregressionequationdevelopedfromtherelationshipbetweentheNewGardenandCecilCountymonitorisusedtofillinmissingdatafortheNewGardensiteinanyquarterinthemostrecentthree-yearperiodthatdidnothave75percentcompletenessbasedonactualobservations,sothatthenormaldatacompletenessrequirementof75percentofdataineachquarterofthethreeyearsismet.Afterthemissingdataforthesiteisfilledin,theresultsareverifiedthroughanadditionalstatisticaltest.Theadditionalstatisticaltestused,referredtoasbootstrapping,examinesthedifferences4betweenthepredictedfilled-inconcentrationsandtheactualobservedconcentrationstodetermineifthedesignvaluesforthemonitorwithincompletedatameettheannualNAAQSforPM2.5EligibilityEPAestablishedcriteriatoassurethattheDVfortheNewGardenmonitorinthePhiladelphianonattainmentarea,asestimatedbythemethod,wasrobustenoughtoallowconsiderationoftheresultsinaweightofevidencedecision.EPAestablishedcriteriabothfortheoperatingperiodofthecomparisonmonitor(CecilCounty)andforthenumberofdaysofsamplesthatthecomparisonsmonitor(CecilCounty)andtheNewGardenmonitorhaveincommon.EPAhasnotestablishedbrightlinesorspecificrequirementsfordeterminingDVsformonitorswithlessthancompletedata.OperatingperiodThecandidatemonitor(CecilCounty)operatedduringthe3-yearperiod(2007-2009)areainwhichthetargetmonitor(NewGarden)hasincompletedatawhichestablishesasignificantrelationshipbetweenthemonitors.Thecandidatemonitor(CecilCounty)doesnotnecessarilyhavetohavecompletedatainall12quartersofthe3-yearperiod,butthecandidatemonitor(CecilCounty)hasenoughobservationstoallowittobeusedtofillinenoughmissingdaysforthetargetmonitor(NewGarden),sothattheNewGardenmonitorwillendupwithatleast75percentcompletenessinall12quarters.PairedsamplesPairsofsampledatafortheNewGardenmonitorandCecilCountymonitorfromthemostrecent20-quarterperiodofoperationofthetargetmonitorwasused.The“periodofoperation”oftheNewGardenmonitorwasbasedonthedateofthelastreportedsamplefromthemonitor.TheCecilCountymonitorhadatleast100historicalsamplepairsincommonwiththeNewGardenmonitorduringthisperiod.Whenthereweremorethan100pairsinthe20-quarterperiodallavailablepairswereused.Inadditiontothe100pairsoverthe20-quarters,candidatemonitorshadatleast20paireddaysofdataincommonwiththeNewGardenmonitorforeachcalendarquarter(addingtogetherthenumberofdaysinagivencalendarquarter[Qi,Q2,Q3,orQ4jacrossthe20-quarterperiod).Severalcandidatesitesmettheeligibilitycriteriaof100pairsoverthe20-quarters,andatleast20paireddaysofdataincommonwiththeNewGardenmonitorforeachcalendarquarter.MethodfordeterminingdesignvaluesStep1—Organizedataandperformlinearregression(s)betweentheNewGardenandcandidatemonitorsinthePhiladelphiaArea.AlltheavailablepaireddatawithintheperiodlimitdescribedintheEligibilitysectionwasusedtodevelopalinearregressiontopredicttargetconcentrationsfromcandidateconcentrations.Aregressionwasperformedforeachpossiblepairingthatmetthecriteriautilizedfor100datapointsand20datapointspercalendarquarter(acrossallyears)inthemostrecent20quartersforeachcandidatemonitorinthevicinityofthePhiladelphiaArea.5Step2—SelectCandidatesiteThePhiladelphiaAreahasalargenumberofmonitorswhichcouldhavebeenusedascandidatesites.TheNewGardenmonitoringsiteistheonlyrurallysitedPM2.5siteinthePhiladelphiaArea.ItcausedEPAtolookoutsideofthePhiladelphiaAreaforacandidatesite.Onlyonecandidatemonitor(CecilCounty,monitor240150003)wasselectedfortheNewGardenmonitor.ThefollowstepswereusedtoselecttheCecilCountymonitor.1)Allcandidatemonitorswereplacedintoorderofhighestcorrelation(highestr-squaredinthelinearregression)withNewGarden.2)UsingtheregressionequationrelatingconcentrationsattheNewGardenmonitorandtheCecilCountymonitor,estimatesofthe24-houraverageconcentrationsweremadeattheNewGardenmonitorforallmissingscheduleddaysintheinitiallyincompletequarters,inthemostrecentthree-yearperiodatNewGarden.EstimateswereonlymadefordaysonwhichaconcentrationisavailableattheCecilCountymonitor.EstimateswerenotmadeforanydaysinthequarterforwhichtheNewGardenmonitorhad75percentormorecompletedatainitially.TheestimateswerecombinedwithanyreporteddataattheNewGardenmonitorintherecent3-yearperiodandthedatacapturerateswerecomputedfortheoriginallyincompletequarter.ThecomputationofdatacaptureratesrequiredanassumptionthattherequiredsamplingfrequencyfortheNewGardenmonitorwasrecorded.IftheCecilCountymonitorhadalowersamplingfrequencythantheNewGardenmonitor,somemissingscheduleddaysfortheNewGardenmonitorwerenotsubstitutedfortheregression-basedestimates.WhentheCecilcountymonitorhadalowersamplingfrequencythantheNewGardenmonitor,theNewGardenmonitorsamplingschedulewasassumedtobeacombinationoftheNewGardenandCecilCountymonitorsschedules,weightedbythenumberoforiginallypresentandoriginallymissingscheduleddaysattheNewGardenmonitor.3)If,afterperformingtheprocessinStep2,theresultsproduceall12quartersattheNewGardenmonitorhavingatleast75percentofscheduledvalues,theCecilCountymonitorwasselectedastheCandidatefortheremainingsteps.Step3—DesignValueComputedThethree-yeardesignvaluewascalculatedusingtheactualobservationsoftheNewGardenmonitorandtheregression-basedestimatesofdailyconcentrations.ThedesignvaluefortheNewGardenmonitorinthePhiladelphiaAreawasbelowtheNAAQS.Step4—StatisticalconfidenceofadesignvaluebelowtheNAAQScheckedTheresultsofStep3showedthedesignvaluefortheNewGardenmonitorinPhiladelphiaAreatobebelowtheNAAQS.Inordertoshowthatthereisatmosta10percentprobabilitythattheactualdesignvalue(hadtheNewGardenmonitoroperatedmoredays)wasabovetheNAAQS,furtheranalysiswasperformedasfollows:6a)Residualswerecalculatedfromtheregression.b)Abootstrapanalysiswasperformed,repeatingtheregression-basedsubstitutioninStep2butaddingtoeachestimated24-hourvaluethatsubstitutesforamissingscheduledmonitoredvalueaplusorminusresidualthathasbeenrandomlydrawn(withreplacement)fromthepoolofregressionresiduals.Thissteprandomlyappliesrealresidualsfromthelinearregressiontotheimputedcurrent-periodTargetvalues.c)Repeat(b)foratotalof1000runs.d)Foreachofthe1000bootstraptrials,the3-yeardesignvaluewascalculated.Thiswillprovideapseudoconfidenceintervalforthepartiallyimputedcurrent-perioddesignvalueforNewGarden.e)Sincenoneofthe1000runsresultedinadesignvalueabovetheNAAQS,theNewGardenisconsideredtohavemettheNAAQS.DeterminingthedesignvalueforNewGardenmonitor420290100Steps1and2wereperformedwithNewGarden(monitor420290100)asthetargetmonitor.TheresultsoftheregressionscanbefoundinFigure2,attached.OnFigure2,theNewGardenmonitorislistedasSiteA.TheCecilCountysitethatwasusedislistedasSiteB.ThemonitorCecilCounty,(AQSID:240150003),wasbestsuitedtobeusedasSiteBbecauseitissimilarlysitedtotheNewGardenmonitormakingtheCecilCountysiteinfluencedbysimilarimpacts.CecilCountymettheoperatingperiodandpaireddataeligibilitycriteriaforbeingaCandidatesite.TheresultsoftheregressionbetweentheNewGardenandCecilcountymonitorisshowninFigure3,attached.Estimatesforthemissingdatafor2007and2008,weremade.Asaresultoffillinginthemissingdata,theNewGardenmonitornowhadcompletedatafor2007and2008.Adesignvalueof14.0ig/m3wascalculatedfortheNewGardenmonitorwhenthemissingdatawasfilledinFigure4,attached.ThestatisticalconfidenceofthedesignvaluewascheckedusingthemethodoutlinedinStej4.Theresultsofthe1000bootstraptrialsprovidedthefollowingresults:3DVsof13.8jig/m,72DVsof13.9Ig/m3,559DVsof14.0tg/m3,344DVsof14.1tg/m3,and22DVsof14.2jtg/m3.Noneofthe1000bootstrappingtrialsresultedinaviolatingDV,whichprovidesstatisticalconfidencethattheNewGardenmonitorisattainingthe1997annualPM2,5NAAQS.Figure5,attached,showstheresultsofthebootstrapping.3)MonitorShutdownsandStartupsMonitors421010136and421010055,PhiladelphiaCounty,PennsylvaniaMonitor421010136,knownas“Elmwood,”wasshutdownbythePhiladelphiaAirManagementServices(AMS)onDecember31,2007.Thephysicalsitewentunderconstructiontobeupdatedwithanewshelter,fencingandconcretepad.ThelastcompleteannualdesignvalueattheElmwoodmonitorwas13.6j.tg/m3,considering2002-2004data,whichmeetstheannualNAAQS.Becausethismonitorwasshutdownafter2007,datafromElmwoodisnotreflectedinTables1and2.Anewmonitoringsitelocatedat24thandRitnerStreets,approximately2milesfromtheElmwoodsite,wasstartedshortlyafterinJanuary2008.This“Ritner”site,monitor421010055,7isamulti-pollutantairmonitoringsiteandmoresuitedtomonitorPM2.5particulate.ThemonitorfromElmwoodwasrelocatedtotheRitnersiteanddidnotreturntothesite421010136.Monitor340070003,CamdenCounty,NewJersey:EmergencyShutDownTheNewJerseyDepartmentofEnvironmentalProtect(NJDEP)shutdownmonitor34-007-0003inCamdenCountyin2008.Monitor34-007-0003,whichhadbeeninoperationsince1968,wasunexpectedlydiscontinuedonSeptember29,2008duetolackofsecurityatthestation.NJDEP,incoordinationwithEPA,isactivelypursuingtheestablishmentofanewmonitoringstationinCamden.Therefore,itisnotappropriatetoconsiderthismonitorinthedeterminationofattainmentforthePhiladelphiaArea.Thelastvalidannualdesignvaluewas13.4ig/m3,considering2005-2007data.ThisdesignvaluemeetstheannualNAAQS.Attachments:-EPAAQSQuickLookReport(AMP48O),datedAugust18,2011,containing2007-2010annualPM25airqualitydataforDelaware,NewJersey,andBuckCounty,PennsylvaniaportionsofthePhiladelphiaArea.-EPAAQSQuickLookReport(AMP48O),datedAugust18,2011,containing2007-2010annualPM2.5airqualitydatafortheChester,Delaware,Montgomery,andPhiladelphiaCounties,Pennsylvania.-Figure1.PhiladelphiaAnnualDesignValueHistory.-Figure2.PhiladelphiaSitesand2007-2009DVs&DataCapture.-Figure3.LinearRegressionResults.-Figure4.ImputationandResultingDataCaptureandDVRecalculation.-Figure5.BootstrappingResiduals(andDVRecalculations).8