UNITEDSTATESENVIRONMENTALPROTECTIONAGENCYREGIONIII1650ArchStreetPhiladelphia,Pennsylvania19103DATE:21September2011SUBJECT:TechnicalSupportDocumentRegardingOzoneMonitoringData—Delaware,Maryland,NewJersey,andPennsylvania;DetenninationsofAttainmentofthe19978-HourOzoneNationalAmbientAirQualityStandardforthePhiladelphiaWilmington-AtlanticCity8-HourOzoneModerateNonattainmentAreaFROM:



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rkAiiorAirQualityPlanningSpecialistOfficeofAirProgramPlanningTO:FileTHRU:ritiOfficeofAirProgramPlanningThisdocumentprovidesatechnicalreviewoftheairqualitymonitoringdatausedtosupporttheEnvironmentalProtectionAgency’s(EPA’s)proposeddeterminationthatthePhiladelphiaWilmington-AtlanticCity,PA-NJ-MD-DE8-hourozonemoderatenonattainmentarea(thePhiladelphiaArea)hasattainedthe1997ozonenationalambientairqualitystandard(NAAQS)byitsstatutoryattainmentdateandEPA’sproposedcleandatadetenninationforthePhiladelphiaArea.I.BACKGROUNDThisPhiladelphiaAreaincludestheentireStateofDelaware;CecilCountyinMaryland;Atlantic,Burlington,Camden,CapeMay,Cumberland,Gloucester,Mercer,Ocean,andSalemCountiesinNewJersey;andBucks,Chester,Delaware,Montgomery,andPhiladelphiaCountiesinPennsylvania.ThePhiladelphiaAreawasclassifiedasamoderatenonattainmentarea.See40CFR81.808,81.321,81.331,and81.339.Moderateareasarerequiredtoattainthe19978-hourozoneNAAQSbynolaterthanJune15,2010.See40CFR51.903.However,theEPAapproveda1-yearattainmentdateextensionforthePhiladelphiaAreaonJanuary21,2011.(See76FR3838and76FR3840.)ThePhiladelphiaArea’sattainmentdateisnowJune15,2011.II.EVALUATIONOFAIRQUALITYMONITORINGDATAA.DataRequirementsThecriteriafordeterminingifanareaisattainingthe19978-hourozoneNAAQSaresetoutin40CFR50.10andappendixI.Thedeterminationisbasedonthemostrecentthreecomplete,consecutivecalendaryearsofquality-assuredairqualitymonitoringdataatallozonemonitoringsitesinthearea.Toattainthisstandard,ateachmonitortheannualfourth-highdailymaximum8-hourozoneconcentrationsmeasuredaveragedoverthethree-yearperiod(themonitoringsite?sozonedesignvalue)mustnotexceedtheozonestandard.Thelevelofthe19978-hourNAAQSforozoneis0.08partspermillion(ppm).Basedonanozonedataroundingconventiondescribedin40CFRpart50,appendixI,thestandardismetifozonedesignvalueis0.084ppm(i.e.,84partsperbillion)orlower.Whenthedesignvalueislessthanorequalto0.084ppmateachmonitoringsitewithinthearea,theareameetstheNAAQS.Thedatamustbecollectedandquality-assuredinaccordancewith40CFRpart58,andmustberecordedinEPA’sAirQualitySystem(AQS).Thedatasupportingattainmentofthestandardmustbecompleteinaccordancewith40CFRpart50,appendixI.Thedatacompletenessrequirementismetwhenthepercentofdayswithvalidambientmonitoringdata,averagedoverthreeyears,isgreaterthan90%,andnosingleyearhaslessthan75%datacompleteness.ForthePhiladelphiaArea,theozoneseasonextendsfromthebeginningofAprilthroughtheendofOctober.Acompleteozoneseasonconsistsof214monitoringdays.B.CertifiedAirQualityMonitoringData,2008-2010TheStatesofDelaware,Maryland,andNewJersey,andtheCommonwealthofPennsylvania(“theStates”)submittedcomplete,qualityassuredairqualitymonitoringdataintoAQS.TheStatesthencertifiedthatdata.AttachedaretwoAQSreportscontaining8-hourozonedataforthePhiladelphiaAreafor2008to2010.Table1,below,summarizesthosereports.Table1:2008-2010PhiladelphiaArea8-HourOzoneDesignValues&DataCompleteness.PercentCompleteness4thHighestValue(2008-2010(validmonitoreddaysIStateCountySiteIDppm,DesignValuerequired_days)200820092010(ppm)2008200920102008-2010averageDEKent10-001-00020.0810.0660.0770.07410099100100‘JewCastle10-003-10070.0780.0680.0800.0759990869210-003-10100.0820.0680.0790.0769579858610-003-10130.0770.0690.0800.075100979798Sussex10-005-10020.0810.0670.0840.0779998999910-005-10030.0790.0690.0830.077100979397MDCecil24-015-00030.0880.0720.0820.08096949394Atlantic34-001-00060.0720.0710.0800.07495949896Camden34-007-00030.0838134-007-10010.0820.0710.0880.08098969897NJCumberland34-011-00070.0790.0720.0770.07698999798Gloucester34-015-00020.0890.0710.0830.08196999998Mercer34-021-00050.0790.0710.0860.07899979998Ocean34-029-00060.0850.0710.0870.0811009896982PercentCompleteness4thHighestValue2008-2010(validmonitoreddays/(ppm)StateCountySiteIDDesignValuerequired_days)(ppm)2008-2010200820092010200820092010averagePABucks42-017-0.0890.0740.0870.0839810099990012Chester42-029-01000.0840.0670.0770.07699989597Delaware42-045-00020.0810.0650.0760.074100989698Montgomery42-091-00130.0840.0700.0810.078971009898Philadelphia42-101-00040.0620.0590.0770.0669899959742-101-00240.0870.0720.0880.0821008510095AsshowninTable1,above,all2008-2010designvaluesarebelow0.084ppm.Allbuttwomonitors:10-003-1010and34-007-0003,meetthedatacompletenessrequirements.Informationonthedatacompletenessissuesformonitors10-003-1010and34-007-0003follows.Monitor10-003-1010,NewCastleCounty,Delaware:DataCompletenessIssuesAccordingtoappendixI,atleast75%datacaptureisrequiredeachyear,andthepercentageofdayswithvalidmonitoringdataaveragedoverthreeyearsmustbegreaterthan90%.However,formonitorsthatdon’tmeettheserequirements,certaindatasubstitutionisallowed.“Whencomputingwhethertheminimumdatacompletenessrequirementshavebeenmet,meteorologicalorambientdatamaybesufficienttodemonstratethatmeteorologicalconditionsonmissingdayswerenotconducivetoconcentrationsabovethelevelofthestandard.Missingdaysassumedlessthanthelevelofthestandardarecountedforthepurposeofmeetingthedatacompletenessrequirement,subjecttotheapprovaloftheappropriateRegionalAdministrator.”MissingOzoneDataAnalysis#1:In2009,monitor10-003-1010inNewCastleCounty,DE,recordeddataon113days,whichis53%ofthe214-dayozonemonitoringseason.InJuly2010,theDelawareDepartmentofNaturalResourcesandEnvironmentalControl(DEDNREC)submittedtoEPAamissingdataanalysisforthismonitorforthe2009ozoneseason.Thatanalysis,datedJuly19,2010,usesthedatasubstitutionprovisionsofappendixIto40CFRpart50todeterminethat55ofthedayswhenmonitor10-003-1010wasdownin2009hadmetrologicalconditionsthatwerenotconducivetoozoneformationabovethelevelofthe2008ozoneNAAQS,0.075ppm.Basedonthisanalysis,DEDNRECrequestedthat55dayswithmissingmonitoringdatabecountedindeterminingdatacompletenessfor2009.EPARegionalAdministratorShawnM.GarvinapprovedthatrequestinaletterdatedSeptember24,2010.DEDNREC’sdatasubstitutionanalysisandEPA’sapprovalletterareattached.Table2.2009DataCompletenessforMonitor10-003-1010,NewCastleCounty,DEAfterEPAApprovalofDEDNREC’sJuly2010MissingDataAnalysisYear-DayswithValidOzoneAdditionalTotalDaysPercentMeasurementsApprovedDaysCountedforDataCompletenessCompleteness20091135516879%3Table2showsthatwiththeadditional55dayscountedtowardscompletenessformonitor10-003-1010,datacompletenessfor2009increasesfrom53%to79%.Table1isasummaryofaMay27,2011EPAAQSQuickLookReport.Thereportshowsthe113daysofactualrecordeddata.However,thisreportalsoshowsthatmonitor10-003-1010has79%completeness,whichreflectstheadditional55daysapprovedbyEPA.MissingOzoneDataAnalysis#2:AsseeninTable1,thethreeyearaveragecompletenessformonitor10-003-1010inNewCastleCounty,DEis86%,whichisbelowtherequired90%.OnJuly11,2011,theDEDNRECsubmittedasecondmissingozonedataanalysisformonitor10-003-1010forthe2009and2010ozoneseasonsusingthedatasubstitutionprovisionsofappendixIto40CFRpart50.TheDEDNRECmissingozonedataanalysislistedcertaindaysin2009and2010whennoozonedatawascollected.However,eventhoughnodatawascollected,documentationandanalysisprovidedbyDEDNRECjustifiedthesedaysshouldbecountedfordatacompletenessrequirements.DEDNRECprovidedstrongstatisticalcorrelationsbetweenmonitor10-003-1010andnearbyozonemonitoringstations,aswellas,observedmeteorologicalconditionsthatwerenotconducivetoozoneformationtojustifimissingozonedatadayswouldnothaveexceededthe19978-hourozonestandardof0.08ppm.InaletterdatedSeptember1,2011,EPARegionalAdministratorShawnM.Garvin,approvedDEDNREC’srequesttoallowanadditional15daysin2009and19daysin2010tobecountedtowardsdatacompleteness.Theadditionalvalidmonitoringdaysincreasesthepercentagedatacapturefor2009and2010,andbringsthethreeyearaveragedatacompletenessfor2008—2010abovetherequired90%,asshowninTable3.DEDNREC’s’sdatasubstitutionanalysisandEPA’sapprovalletterareattached.Table3.2008-2010DataCompleteness,Monitor10-003-1010,NewCastleCounty,DE,AfterEPAApprovalofDEDNREC’sJuly2011MissingDataAnalysisYearDayswithValidOzoneAdditionalTotalDaysPercentMeasurementsApprovedDaysCountedforDataCompletenessCompleteness2008203---20395%20091681518386%20101811920093%2008—2010Average91%Monitor34-007-0003.CamdenCounty,NewJersey:EmergencyShutDownTheNewJerseyDepartmentofEnvironmentalProtect(NJDEP)shutdownmonitor34-007-0003inCamdenCountyin2008.TheCamdenLabstation,monitor34-007-0003,whichhadbeeninoperationsince1968,wasunexpectedlydiscontinuedonSeptember29,2008duetolackofsecurityatthestation.NJDEP,incoordinationwithEPA,isactivelypursuingtheestablishmentofanewmonitoringstationinCamden.Therefore,itisnotappropriatetoconsiderthismonitorinthedeterminationofattainmentforthePhiladelphiaArea.42008-2010DataComparisontoNAAQSEPAhasdeterminedthatitisnotappropriatetoconsidermonitor34-007-0003inCamdenCounty,NewJerseyduetoitsemergencyshutdown.AsshowninTable1,2008-20108-hourozonedesignvaluesforallothermonitorsinthePhiladelphiaAreaare0.084ppmorless.Thedatasubstitutionanalyses,describedabove,formonitor10-003-1010inNewCastleCounty,Delawareresultsin70additionaldaysofdatain2009and19additionaldaysin2010.Withtheapprovedadditionalmissingdayscountedtowarddatacompleteness,the2008-2010three-yearaveragecompletenessisnow91%,whichisgreaterthanthe90%required.Thus,whenconsideringthedatasubstitutionanalysisformonitor10-003-1010,allmonitorsmeetthecompletenesscriteria.Therefore,thePhiladelphiaAreameetsthe19978-hourozoneNAAQS,considering2008-2010data.Attachments:-EPAAQSQuickLookReport(AMP45O),datedMay27,2011,containing2008-2010ozoneairqualitydataforDelaware,Maryland,andPennsylvaniaportionsofthePhiladelphiaArea.-EPAAQSQuickLookReport(AMP45O),datedAugust19,2011,containing2008-2010ozoneairqualitydataforNewJerseyportionofthePhiladelphiaArea.-September24,2010EPAlettertoDEDNRECapprovingDEDNREC’sJuly15,2010“DataSubstitutionAnalysis;2009Ozone;Brandywine(AQSSiteID10-003-1010).”DEDNREC’sJuly15,2010,“DataSubstitutionAnalysis;2009Ozone;Brandywine(AQSSiteID10-003-1010),”submittedviacoverletterdatedJuly19,2010.September1,2011EPAlettertoDEDNRECapprovingDEDNREC’sJuly11,2011“MissingOzoneDataAnalysis;2010andSupplemental2009forBrandywine(AQSSiteID10-003-1010).”DEDNREC’sJuly11,2011“MissingOzoneDataAnalysis;2010andSupplemental2009forBrandywine(AQSSiteID10-003-1010),”submittedviacoverletterdatedJuly11,2011.5