OrrrcroFTHEGovrnNonRICKPERRYGOVERNORFebruary29,2012AlArmendariz,Ph.D.RegionalAdministratorU.S.EnvironmentalProtectionAgency(EPA),Region61445RossAvenue,Suite1200Dallas,Texas75202-2133DearDr.ArmendarizI'mwritinginresponsetoyourDecember9,2011,proposaltomodifythestate'srecommendationfordesignationofareasinTexaswithregardtothe2008NationalAmbientAirQualityStandard(NAAQS)foreight-hourozoneof0.075partspermillion.IrespectfullyrequestthatyounotenacttheplanneddesignationofHood,Matagorda,andWisecountiesasozonenonattainmentareas,TheenclosedanalysisperformedbytheTexasCommissiononEnvironmentalQuality(TCEQ),submittedpulsuanttoSectioni07(dX1XB)oftheFederalCleanAirAct,demonstratesthereisinsuffrcientscientificjustificationforEPA'sproposedmodificationofthestate'srecommendationforthesethreecounties.Thesecountiesdonotmeasurenonattainmentatafederalregulatorymonitor,nordotheysignificantlycontributetoelevatedozonemeasurementsatanyviolatingmonitorsintheadjacentcounties.Infact,EPAhasalwaysdesignatedHood,Matagorda,and'Wisecountiesasattainment/unclassifiableforozone.TCEQ'sanalysisindicatesthatsignificantreductionsinnitrogenoxide(NOx)emissionshaveoccurredinHood,Matagorda,andWisecountiesinthepasteightyears.Currentpermittingandrulerequirements,combinedwithtechnologicaladvancementsinindustrialequipment,areanticipatedtocontinuethisdownwardtrendinNOxemissionswithouttheneedfortheimpositionoffurtherrulesandprogramsoncitizensandbusinessesinthethreecounties.Anonattainmentdesignationforthesethreecountieswillundoubtedlystifleeconomicgrowthwhileprovidinglittle,ifany,environmentalbenefit.WehaveworkedhardinTexastostrikeabalancebetweenmeaningfulenvironmentalregulationandeconomicgrowth,anddesignatingthesecountiesasnonattainmentisnotadecisionthatshouldbetakenlightly,especiallyduringthesetougheconomictimes.IthankyouforyourPosrornceB,ox1.2428Ausrn,Trrus787t1(512)463-2000(voIce)/Dtx7-1'-1ronR¡mvSenvlcBsVrsnwwv.Tn<¡,sO¡u¡¡re.co[rrrr¡OrncnrWesSITEortt¡rSmruorTnx¡sAlArmendariz,Ph.DFebruary29,2072Page2considerationofthisissue.Ifyouhaveanyquestionsorneedadditionalinformation,pleasefeelfreetocontactTCEQChairmanBryanShawat(512)239-5510.Sincerely,HRickPerryGovernorRP:jhpEnclosuresccBryanW.Shaw,Ph.D?*lBryanW,Shaw,Ph.D,,Chai.rmanBudclyGalcia,ConntissionerCarlosRubinstein,ComrnìssionerMarkR.Viclrery,P,G,,F)xeauhueDire.ctor--.=--/,,\ñ\tirrl.\(,({'ii*.u,li)\".'rIl¡ljr;'f\'tl.,/\--./TsxasConnwssloNoNBuwnoNMENl'ALQu¡l,lrvProtecting|'exasbyRøducingandPreuentíngPolhnon._-,,----..--:,---...--....-TheHonorableRickPerryGovernorofTexasStateCapitolP.O,Boxtz4z9Austin,TXTBTtt-z4zBDearGovernorPerry:InaDecemberg,zoLi.lettel,theUniteclStatesBnvironmentalProtectionAgency(EPA)saiditintenclstoexpandtheDallas-FortWorth(DFW)andHouston-Galveston-Brazoria(HGB)ozonenonattainmentareas.ThisplanisinconsistentwiththeTexasnonattainmentdesignationrecommenclaiionyousubmittedtotheEPAinOctoberzort,I¡ecommendyouasktheEPAtoteversethisplan,becausethereisinsufficientscientificjustificationfortheEPAsploposedexpansionofthesetwoozonenonattainmentareas.ErrclosedforyourconsiderationisacomprehensivetechnicalanalysisthatsupportstheTexaspositionaswellasadrafttransmittalletterforyoursignature.StateresponsestotheEPAareduenolaterthanFebruary29,zo7z,Thefederalairqualitystandard.atissueistheEPAszooBNationalAmbientAir.QualityStandardforeight-hourozoneofo.o7gpartspermillion.TheBPAhassaiditintendstofÏnalizezoo8eight-hourozonenonattainmentareadesignationsbyMaygr,zor2.SectiontoZ(dXtXB)oftheFederalCleanAirActplovidesstatestheopportunitytodemonstratewhytheEPA'smodificationstostatenonattainmentareareeommendationsarenotappropriate,ThetechnicalanalysisprovidedhereisanexpansionoftheresponsealreadysubmittedtotheBPAonthismatteronJanuaryrg,2orz,bytheTexasCommissiononEnvironmentalQualifyduringabriefEPApuÌ:iiccommentperíoclannounced,intheFederalRegisteronDecember20,zo1t,overlheholidays.ThecountiesatissueareHoodandWiseCountiesinth,eDFWareaandMatagordaCountyintheHGBarea.Thesethreecountiesneitherfiìeasurenonattainmentatafecleralregulatoryozonemonitorfortheyearsinquestion,zooBthroughzoro,nordotheysignificantþcontributetoelevatedozonen'r.easurements¿rtviolatingozonemonitorsinacljacentcounties.Inaddition,thesethreecountieshavealwaysbeendesignateclbytheEPAasattainment/unclassifiedfor[hefederalozonestandards.Thankyouforyoutsupportinthismatter,IfIcanbeofanyassistanceinsubmittingaTexasresponsebytheFebruaryzgduecìate,pìeasecontactmeat(5rz)289-SS1o..Síncerely,3qn'6fi'dc*;u,^uûShaw,Ph.D.ChairmanEnclosuresP.O.Boxr3oB7Austin,Texas787tt4oï7.E1z-239-1ooo'www,tccq.texas,govIriililII'I:!Irl'i,lIi1Iì:'I'ji-lI,'I1II,lIfowisoutcnstonerservice?wvvw.tceq.texas,gov/goto/customersut'veylri'rl¡'l"¡¡¡.r,I,',1lr,trrfrr,iuj::,\'lu:r'rlirrl,:BryanW.Shaw,Ph.D,,Chaún:'nttBuddyGarcia,Conrnissionei'CallosRubinstein,ComrnissionerMarkR.Viclrery,P.G,,ExeativeDu'ectot'TnxasCotr,ltr,rssroNoNB¡rwnouMENTALQueltrvPt'otcctìltgTexøsbyReclucíngandh'eventíngPollutíonJanuary71.,2ot2U,S.EnvironmentalProtectionAgencyMailCode6rozTtzooPennsylvaniaAvenue,N.W.Washington,D.C.20460Attn:DocketIDNo.EPA-HQ-OAR-zoo8-o476Re:UnitedStatesEnvironmentalProtectionAgency(trPA)ResponsestoStateandTl'ibal2ooBOzoneDesignationRecommendations:NoticeofAvaiiabiLityandPublicCommentPeriodDearSirorMadam:TheTexasCourmissiononBnvironmentalQuality(TCEQ)providesthefollowingcommentsonEPA'sresponsetotheTexasrecommendationforeooBozonenonattainmentdesignations.'IheavailabilityofapubliccommentperiodwaspublishedintheDecernberzo,2otl,FerlerqlRegister(26FRZBBfz),TheEPA'stirningofthe3o-daycotnmentperiodduringtheholidayseasonsevereþrestrictedtheTCEQ'sabilit¡rtoprovidethoroughcornmentswithinthestipulatedtimeperiod.Insholt,theTCEQbelievesthattheEPAshouldreverseitsplantoexpandTexasnonattainmentareasinHoustonandDallasbecausethereisnoscientificjustificationfortheproposedexpansion.Thecountiesinquestionneithermeasurenonattainmentatafederalr:egulatoryrnonitornordotheysignificantlytransporl.ozoneprecursorstovioìatingrnonitors,Background.Foritszorzimplernentationofthe2oo8ozonestanclard,theEPAsaidinaDecernberg,zoLr,iettersenttothegovernorthatitwoulclexpancì.theHouston-GalvestorrBrazoria(HGB)andDallas-FofiWorth(DFW)ozonenonattainmentareas.Theseareaswereestablishedinzoo4toimplernenttheLggTozonestandard.Inparticular,theEPAsaiditintendstoadd:Matagorcì.aCountytotheHGBeight-countynonattainmentatea,andHoodanclWiseCountiestotheDFWnine-countynonattainmentarea.(ThegovernorhaclrecornnrendedthattheHGBarearemaineightcountiesandtheDFWarearemainninecounties.)'IireBPArelieclsignificantlyonmeteorology(weather'/transportpaLterns)tojustifytheinclusionofthethreecountiesasnonattainment.TheTCBQbelievesthattheuseoftheNationalOceanicandAtmosphericAdministrationSingleParLicleLagrangianIntegrateclTlajectoryModel(HYSPLIT)wasunsoundlyappliedascorloborativesupportforexpandingtheFIGBandDIWnonattainrnentareas,I-IYSPLITcannotprovideevidencedirectlylinkingemissionsfrornoneareatoozoneformationinanotherarea.Furtherrnole,I-IYSPLITdoesnothavetheabilitytocalculatepoìlutantconcentra[ions,LhetypesofpollutantsaddedalongthetransportpathfromP,O,Boxt3oBT.Austin,Texas787u1o87.512-239-1ooo.www,tceq.texas.govHowisourcustomerscrvíce?v¡ww.tceq,texirs.gov/goto/custornelsurveyI'iir¡i'rl,,rrrr'v'l,rllrrttrr':.rrr'"".,l'¡r,lii,l;DocketIDNo,EPA-HQ-OAR-2008-0476Page2differentaïeasrpollutantdispersdratesalongthetransportpath,orozoneformationratesthatmayresultfromcliffelentpollutantintelactions.TheEPAalsoreliedonemissionsinventorydata.However,theEPAdidnotusethemostcurrentemissionsinventorydatasubmittedbythestate,Emissionsinventorydismepanciesarediscussedbelow.MatagordaCounty.TheEPAstatedthatMatagordaCountyshouldbedesignatednonattainmentbecauseofhighemìssionsandawindpatternthatindicatesemissionscouldattimesimpactviolatingmonitors.TheTCEQclisagleeswiththisanalysisbecauseernissionsareinfactsubstantiallylowerthanthosecitedbytheBPAandbecauseTCEQ'stechnicalanalysisshowsthatveryfewwindtrajectoriesthaltravelthroughMatagordaCountyimpactviolatingmonitors.Furthermole,MatagordaCountydoesuolhaveafederalregulatoryozonemonitor,doesnotsignificantlycontributemobile-orareasourceemissionstotheHGBnonattainmentarea,andisoutsidethejulisdictionalboundaryoftheHoustonarea'sMetropolitanPlanningOrganization.MatagordaCounty'seoropopulation,whichhasdeclineclbyS%betweeneoooand2010,isapproximaLely37,oooresidentscornparedtotheHGBnonattainmentareapopulationofapproximately6millionresidents.Regardingemissions,theEPADecember9lettercitedhighernissionsthatincludednon-roadsourceemissionscalculatedfrornBPA-derivedsulrogate.s.However,inMayzo1o,theTCBQsubmittedlocallyobtainednon-roademissionsdatafromcommercialrnar"inevesselsandlocomotivestotheEPAfor-thePeriodicBmissionsInventorythatlesultinz,9z8tonspelyearfewet"nitrogenoxides(NOx)emissions.Thiscorlectionisa42%r'eductionfromthetotalemissionsofTooTlorLsperyearcitedbytheEPA.arRegardingwindpatterns,theBPAcÍtedbacktrajectoryanalysisthatshows"attimes"emissionsfromMatagordaCountycouldÍmpactviolatingrnonítorsintheHGBarea.However,areviewconductedbyTCEQtechnicalexpertscreatedbacì<trajectoriesforlìveyears,i.e.,eoo6through2o1o,foldaysmeasuringgleatelthan76partsperbillionattheManvelCroix,TexasCity,andWallisvillemonitorsshowsthatatmostonlyr,B%ofthetrajectoryendpointsactuallytraverseMatagordaCounty,OnthefewdayswhenMatagordaCountywasupwindofaviolatingmonitor,thebacktrajectoliesroutinelycrosseclcountieswithfargleateremissions,Again,abacktrajectorytraversingMatagordaCountycloesnotnecessariþmeanthatemissionsfromMatagordaCountyhaveasignificantimpactonozoneforrnatiorr.HooclCounty.TheEPAstatedthatHoodCountyshouldbedesignatednonattainmentbecauseofconsiderablegrowthinemissionsfromoilandgasdevelopment,awindpatternthatindicatesemissionscouldattimesimpactviolatingmonitors,audahighpopulationgrowth.AlthoughthemostrecentcensusdataindicatethattherehasbeensomepopulationgrowthinHoodCounty,theTCBQdisagreeswiththisanalysisbecauseemissionsareiufactsubstantiallylowerthanthosecitedbytheEPAandbecauseTCEQ'stechnicalanalysisshowsveryfewwindtrajectoriesthatmayirnpactviolatingmonitors,Furthermore,HoodCounty'sdesignvalueforzoo8throughzoromeasutes75partsperbillion,i.e.,attainmentofthezooBozonestandard,DocketIDNo.EPA-HQ-OAR-2008-0476Page3.Regardinggrowthinemissionsfromoilandgasdevelolrrnent,theemissionscitedbytheBPAdidnotincludetheTCBQrevisiontooilandgassectorpneumaticemissionssubmittedOctober2o1r.totheBPAforthePeriodicÈmissionsInventory,whichlesultsinBoBtonsperyearfewervolatileorganiccompound(VOC)emissionsthanthosecitedbytheEPA..RegardingwindpatternsandproximÍtyofemissionstoaviolatingrnonitor,theEPAcitedbacktrajectoryanalysisthatshowsattimesemissionsfromHoodCountycouldirnpactaviolatingrnonitor'.Howevet,TCBQ'stechnicalexpertsindicatethatatmost2.SS%ofthetrajectoryendpointsfromHoodCountyirnpactviolatingmonitors.TheTCBQ'sanaìysisofthedayswiththehighestozoneconcentrationdonotindicatethatHoodCountyemissionsroutineþirnpactDFWmonitors.WiseCounty,TheBPAstatedthatWiseCountyshouldbedesígnatednonattainmentbecauseofitsproxirnitytoviolatingmonitors,growthinemissionsfromBarnettShaiegasploduction,awindpâtternthatindicatesemissionscouldattimesiurpactviolatingmonitors,andgrowthinpopulation.AlthoughWiseCountyisìocatednearsomeviolatingrnonitorsanclthemostrecentcerlsusclataindicatethattherehasbeensomepopulationgrowthinWiseCounty,theTCEQdisagreeswithdrisanalysisbecauseemissionsareinfactsubstantiallyiowerthanthosecitedbytheEPAandbecauseTexastechnicalanaþsisshowsthatfewwindtrajectorieswouldirnpactviolatingmonitors,Furtherrnore,WiseCountydoesnothaveafederalregulatoryozonemonitorandisprimarilyarulalcountywithalowpopulationdensity,'RegardinggrowthinemissionsfromBarnettShalegasproduction,dreemissionsciteclbytheEPAdidnotincludetheTCEQrevisiontooilanclgassectorpneumaticemissionssubmitledOctober2011totheEPAforthePeriodicEmissionsInventory,whichresultsin6,o48tonsperyearfeuterVOCemissionsthanthosecitedbytheBPA..Regardingwindpatternsandproximityofemissionstoaviolatingrnonitor,theEPAcitedbacktrajectoryanalysisthatshowsattimesernissionsfromWiseCountycouldimpactaviolatingmonitor.However,TCBQ'stechnicalexpertsindicatethatatmostz.B7%oofthetrajectoryendpointsfromWiseCountyimpactviolatingmonitors.Conclusion.Inconclusion,EPAhasnotprovidedanadequatejustificationfortheexpansionoftheHGBandDF'Wnonattainmentareasforimplementationofthezoo8ozonestandard.Furthermore,theTCEQbelievestherewouldbenojustifTcationfortheassociatedimpositionofrrrlesandprogramsoncitizensandbusinessesinthesecountiesassociatedwithsuchanonattainmentdesignation.Giventhelackofevidenceinallcases,itappearsEPAcherrypickeddataforthesolepurposeofaddingthesecountiestononattainmentareas.Therefore,theTCEQspecificallyrequeststhattheEPAreverseitsplantoclesignateHood,Matagorda,andWiseCountiesasnonattainmentcounties.DocketIDNo,EPA-HQ-)AR-2008-0476Page4TheTCEQappreciatestheopportunitytoprovidethesecommentsandexpectsthattheStateofTexaswilllespondfurtherbytheFebruaryzg,zetz,deadlinespecifiedintheEPADecember'9,2ou,letter,Ifyouhaveanyquestionsconcerningthesecomments,pleasecontactMr.DavidBqnner,Director,AirQualityDivision,ChiefEngineer'sOffice,572-239-1735,oratdavid.brymer@tceq.texas.gpy.R.Vickery,P.G.,TexasCommissiononQualityTechnicalAnalysisSupportDocurnentationbytheTexasCornmissiononBnvironmentalQuality(TCEQ)RegardingU.S.EnvironmentalProtectionAgency(BPA)ResponsestoStateandTribalzoo8OzoneDesignationRecommendationsEvaluationoftheEPA'sFactorz:EmissionsandEmissions-RelatedDataTheBPAisproposingthatMatagordaCountyshouldbedesignatednonattainmentbecauseoftheamountofemissionsandtheirbeliefthattheseemissionsmay,attimes,impactviolatingozonemonitorsinBrazoriaandHarrisCounties.TheTCEQanalysisofcurrentemissiondataindicatesemissionsinMatagordaCountyareinfactsubstantiallylowerthanthosecitedbytheEPA.TheEPA'sDecemberg,zorr,lettercitedemissionsthatincludednon-roadsourceemissionscalculatedfromEPAderivedsun'ogates.However,inMayzoro,theTCEQsubmittedlocallyobtainednon-roademissionsdatafromcommercialmarinevesselsandlocomotivestotheEPAforthePeriodicEmissionsInventorythatresultinz,9z9tonsperyearfetuernitrogenoxides(NOx)emissionsinMatagordaCounty.Thiscorrectionisa4z%reductionfromthetotalNOxemissionsof7,oo7tonsperyearcitedbytheEPA.TheEPA'stechnicalsupportdocumentstatedthatpopulationandurbangrowthpatternswerealsoconsideredintheirevaluationofemissionsrelateddata.MatagordaCounty's201opopulation,whichhasdeclinedbyg%betweeneoooand2o1o,isapproximately37,oooresidentscomparedtotheHouston-Galveston-Brazoria(HGB)nonattainmentareapopulationofapproximately6millionresidents.TheEPA'sanalysisalsopointsoutthatMatagordaCountyonlyhas343millionvehiclemilestravelledOnViT)comparedwithanarea-wideVMTof96,B7Bmillionmiles.Infact,MatagordaCountyistheonlycountyintheareawithadecreaseinVMT,i.e.,r%o,betweenthezooztozoo8timeperiodreviewedbytheEPA.TheEPA'stechnicalsupportdocumentstatesthat"TotalVMTisanimportantmetricasanindicatorofpotentialcontributiontogroundlevelozoneconcentrations."TheEPAisproposingthatHoodCountyshouldbedesignatednonattainmentinpartduetoconsiderablegrowthinemissionsfromoilandgasdevelopment.Howevet,theemissionscitedbytheEPAdidnotincludetheTCEQrevisiontooilandgassectorpneumaticemissionssubmittedOctober2011totheEPAforthePeriodicEmissionsInventory,whichresultsinBoBtonsperyearfetuervolatileorganiccompound(VOC)emissionsinHoodCountythanthosecitedbytheEPA.TheBPAisproposingthatWiseCountyshouldbedesignatednonattainmentinpartduetoconsiderablegrowthinemissionsfromBarnettShalegasproduction.However,theemissionscitedbytheEPAdidnotincludetheTCEQrevisiontooilandgassectorpneumaticemissionssubmittedOctober2011totheEPAforthePeriodicEmissionsInventory,whichresultsin6,o48tonsperyealfeuerVOCemissionsinWiseCountythanthosecitedbytheEPA.WiseCounty's2o1opopulationis59,tz7residentscomparedtotheDallas-FortWorth(DFW)nonattainmentareapopulationofapproximalely6.2million.TheWiseCounty'szoo8VMTwas969millionmilescomparedwithanarea-wide\rtvlTof6r,9oomillionmiles.EmissionsfromOilandGasDevelopmentNon-combustionsourcesaccountforapproximatelygg%ofzoo8oilandgasareasourceVOCemissionsinHood,Matagorda,andWiseCounties.VOCemissionsfromnon-combustionemissionsourcesintheoilandgasindustryaregenerallyalkanesandwouldnotbeexpectedtosignificantlycontributetoozoneformationduetotheirlowreactivity.TheEPA'stechnicalanalysishasnotdemonstratedthattheseVOCemissionshavehadasignificantimpactonareaozoneformation.TheEPAshouldcarefullyanalyzethechemicalcompositionofVOCemissionsforeachcountyandPageraccuratelyassessthepotentialofthesecompoundstoformozonebasedonreactivityratherthanbasingdesignationsontotalVOCemissions.ThemajorityofoilandnaturalgasVOCemissionsareflashgasemissions.Flashgasemissionsoccurwhenoilorcondensednaturalgashydrocarbonliquidsarereducedtoatmosphericpressureafterextraction.Themajorityoftheheavieralkanesandrelatedcomponentsareprimarilypresentinthishydrocarbonliquid,whichiseitheroilornaturalgascondensate.TheTCEQhassampledflashgasemissionsfromstoragetankslocatedatnaturalgasandoilwellsatapproximately7ositesstatewide.NoneofthelabanalysesforthesesitesreporteddetectablequantitiesofhighlyreactivevolatileorganiccompoundsasdefinedbygoTexasAdministrativeCode(TAC)Chapterrr5.Similarly,theEPASPECIATEsoftware'semissionsprofileforoilandgasproductionactivitiesdoesnotcontainthesecompounds.Therefore,theTCEQwouldnotexpecttheseemissionstosignificantlycontributetoozoneformationinthesecountiesbaseduponcurrentlyavailabledata.Sincethezoozperiodicinventoryyear,MatagordaCountycondensateandgasproductionpeakedin2ooBandhasdeclinedtolevelsbeìowzoozproductionlevels.MatagordaCounty'szoroproductionlevelsforgasandcondensaterepresentanine-yearlowinpro<luction(zoozthroughzoro).Comparedtozoo8peaklevels,2o1ogasproductiondeclinedbyg60/oandzorocondensateproductiondeclinedby49%.YOCareasourceemissionestimatesfromoilandgasproductionhavedeclinedaccordingly,4o%fromzoo8to2o1o.Sincezoo8representsanatypical,outlieryearforbothgasandcondensateproduction,andsincezoroVOCemissionsfromoilandgasproductionhavedeclinedbelowbothzoo5andzoo8emissionsestimates,theoutlierzoo8datashouldnotbeusedeithertoevaluatetheimpactofVOCemissionsfromoilandgasoperationsinMatagordaCountyortopotentiallydesignatethecountyasnonattainmentforozone.SeeTabletformoredetail.Table1:MatagordaCountyGas,Condensate,andOilProductionCondensate(bbl)%"ofzooSCondensateProductionoil(bbl)o/"ofzooSoilProductionYearTotalGas(mscÐ%oofzoo8GasProductionBz7,Bt677%t,245,863358%200238,927,7t7B+%1,325,355SBt%32,391,35170%6zg,6tB59%2O03666,5oo6z%6t9,565tTBo/o2OO427,65t,4o659%t5z%6B%665,t566z%527,52r2OO531,538,651t3o%BB%773,31472%45r,840zoo640,879,75679%374,064toB%200737,OO4,320Bo%849,957t,o69,z4Btoo%o347,868too%ozooB46,5t4,2o7TOOo/o331,11295%BB%757,8r770%20O940,723,3316o6,zzo57%u5%201029,736,7546+%4oo,786Source:TexasRailroadCommission,January13,2ol2SupplementalAnalysisontheEPA'sFactorz:EmissionsandEmissionsRelatedDataIndustrialemissionssourceslocatedinHood,Wise,andMatagordaCountiesarecurrentlysubjecttoseveralstaterules,whicharelistedbelow,limitingtheozoneprecursoremissionsofVOCandNOxasameanstocontrolozonepollution.ManyemissionssourcesinHood,Wise,andMatagordaCountiesarePagezalsosubjecttorulesthatwereadoptedaspartofthestateimplementationplan(SIP)tomeetfederalair'qualitystandards.Manyofthesestaterulesspecifyemissionlimitsandoperatingparametersforavarietyofprocesses.Inaddition,certainsourceslocatedinthesecountiesarerequiredtoobtainasitespecificpermitauthorizationthatincludesbestavailablecontroltechnology(BAgt)requirementsandtheapplicabilityofanystateandfederalrules.NOxemissionsfrommajorindustrialsourceshavedramaticallydecreasedinHood,Matagorda,andWisecountiesbyBo%o,gz"/o,andz5%respectivelyinthepasteightyears(Tablez).ThisreductioninNOxemissionshasoccurredwhilethesecountieshavebeenclassifiedasattainmentanddemonstratesthatreclassificationofthesecountiestononattainmentisnotwarrantedtocontinuetheseemissionreductions.PermittingandrulerequirementscombinedwithtechnologicaladvancementsinindustrialequipmentareanticipatedtocontinuethisdownwardtrendinNOxemissionsfrommajorindustrialsourcesinHood,Matagorda,andWisecounties.Table2:PercentChangeinPointSourceNOxEmissionsinTonsPerYear(tpy)2010',NOxtpy,PércentChangefrom2002To:20L0HoodMatagordaWise5,9642,0442,895L,178972,2,163-80%-s2%-2s%ThespecificstaterulesandgeneralpermittingrequirementsapplicabletoHood,Wise,andMatagoldaCountiesandotherattainmentareasarelistedbelow.CurrentStateRulesApplicableinHoodandWiseCountiesThefollowingstateruleswereadoptedtoreduceVOCemissions:.LowEmissionFuels(GasolineVolatility)-theserulesestablishvolatilityrequirementsforgasolineanddieselfuelsintendedtopowerengines(goTACChapterrr4,SubchapterH,Divisionr)..LoadingandUnloadingofVOC-theserulescontrolVOCemissionsandbyestablishingcontrol,_inspection,testing,andmonitoringrequirementsforgeneralVOCloading,disposaloftransportedvapors,gasolineterminals,gasolinebulkplants,andmarineterminals(Chapteru5,SubchapterC,Divisionr).rFillingofGasolineStorageVessels(StageI)forMotorVehicleFuelDispensingFacilities-theserulesestablishcontrolrequirementsforthetransferofgasolineatavehicledispensingfacility(Chapterrr5,SubchapterC,Divisionz)..ControlofVOCLeaksfromTransportVessels-theserulesprovidetheinspection,testing,andrecordkeepingrequirementsfortank-trucksthatwillbefilledwithgasolineornon-gasolineVOCwithacertainvaporpressure(Chapteru5,SubchapterC,Division3)'ThefollowingstateruleswereadoptedtoreduceNOxemissions:.NitricAcidManufacturing-theserulesapplytoproductionunitsofanynitricacidproductionunitandestablishemissionspecificationsduringmanufacturing(3oTACChapterll7,SubchapterF,Division3)..SmallBoilers,ProcessHeaters,andWaterHeaters-theserulesestablishemissionspecificationsforboilels,heaters,andwaterheatersoperatingunderaspecificcapacitythreshold(Chapterrr7,SubchapterE,Division3).Page3.EastandCentralTexasUtilities(HoodCountyonly)-theserulesapplytounitsusedtogenerateelectricenergyforcompensationincludingutilityelectricpowerboilers,stationarygasturbines,andductburnersusedinturbineexhaustducts(ChapterLL7,SubchapterE,Divisionr)..LowEmissionFuels(LowEmissionDiesel)-theserulesestablisharomatichydrocarbonandcetanenumberrequirementsfordieselfuelsintendedtopowerengines(Chapterrr4,SubchapterH,Divisionz)..DieselEmissionReductionIncentiveProgramforOn-RoadandNon-RoadVehicles(HoodCounty)-theserulesoffergrantopportunitiesforon-roadandnon-roaddieselstoreducedieselemissions(Chapterrr4,SubchapterK,Division3).CurrentStateRulesApplicableinMatagordaCountyThefollowingstateruleswereadoptedtoreduceVOCemissions:.LowEmissionFuels(GasolineVolatiliry)-theserulesestablishvolatilityrequirementsforgasolineanddieselfuelsintendedtopowerengines(Chapterrr4,SubchapterH,Divisiont).¡StorageofVOC-theserulesestablishcontrolrequirementsforVOCstoragetanksandcondensatestoragetanks(Chapter115,SubchapterB,Divisionr)..VentGasControl-theserulesestablishcontrolrequirementsforemissionsofVOCfromprocessvents(Chapter11S,SubchapterB,Divisionz)..WaterSeparation-theserulesprovidecontrolrequirementsforVOCwaterseparators(Chapteru5,SubchapterB,Division3)..LoadingandUnloadingofVOC-theserulesestabìishcontrolrequirementsforgeneralVOCloading,disposaloftransportedvapors,gasolineterminals,gasolinebulkplants,andmarineterminals(Chapterrr5,SubchapterC,Divisionr)..FillingofGasolineStorageVessels(StageI)forMotorVehicleFuelDispensingFacilities-theserulesestablishcontrolrequirementsforthetransferofgasolineatavehicledispensingfacility(Chaptern5,SubchapterC,Divisionz)..ControlofVOCLeaksfromTransportVessels-theserulesestablishtheinspection,testing,andrecordkeepingrequirementsfortank-truckstobefilledwithgasolineornon-gasolineVOCwithacertainvaporpressure(Chapterrr5,SubchapterC,Division3).ThefollowingstateruleswereadoptedtoreduceNOxemissions:.NitricAcidManufacturing-theserulesapplytoproductionunitsofanynitricacidproductionunitandestablishemissionspecificationsduringmanufacturing(Chapterr17,SubchapterF,Division3)..SmallBoilers,ProcessHeaters,andWaterHeaters-theserulesestablishemissionspecificationsandcontrolrequirementsforboilers,heaters,andwaterheatersoperatingunderaspecificcapacitythreshold(Chapterrr7,SubchapterE,Division3)..LowEmissionFuels(LowEmissionDiesel)-theserulesestablisharomatichydrocarbonandcetanenumberrequirementsfordieselfuelsintendedtopowerengines(Chapterrr4,SubchapterH,Divisionz).GeneralNewSourceReview(NSR)PermitRequirementsforanAttainmentArea.Publicnoticerequirements.,Federalrequirementsin4oCodeofFederalRegulations(CFR)Subparts60,6L,and63,whereapplicable,areintegratedintopermitconditions.Page4aBACTevaluationanddetermination,whichincludegoodhousekeepingpractices.Healthimpactsreview,whichrequiresaVOCspeciationdeterminationandcanincludemodeling.OtherGeneralPermittingRequirementsforanAttainmentArearPreventionofSignificantDeterioration(PSD)applicabilitydetermination(PSDisanextensiveandcomplicatedprocessthatisnotcommon)..TitleVpermitsarerequiredformajorsourcesandothercertainsources..StandardpermitsareavailableforcertainindustrialclassificationsourcesandestablishBACTforeachofthoseindustries.OilandGasHandlingandProductionFacilitiesPermitbyRule(PBR)(Chapterro6,SubsectionO,9ro6.gSz)wasupdatedinzorrandappliesintheBarnettShale,whichincludesWiseandHoodCounties.EvaluationoftheEPA'sFactor3:Meteorology(weather/transportpatterns)fortheDFWAreaCurrentUnderstandingofOzoneFormationintheDFWAreaOzoneformationintheDFWarea,asinmostareas,dependslargelyoninteractionofthreefactors:localemissionsofozoneprecursors,ozone-conducivemeteorology,andexistingortransportedbackgroundozoneandprecursors.TheDallas-FortWorth-ArlingtonareaisthefourthlargestmetropolitanareaintheUnitedStates,hometonearly6.5millionresidentsasofzoog(UnitedStatesCensusBureau,2o1o),whichcontributetotheDFW'semissioninventoriesinvariousways.Substantialamountsofprecursorcompounds,chieflyNOxandVOC,areemittedbythreemajorsourcecategories:mobilesources,pointsources,andareasources.Mobilesourcesincludecars,trucks,planes,locomotives,andconstructionequipment.Pointsourcesincludemostindustrialequipment,suchascementkilns;boilers;processheaters;gas,diesel,anddualfuelfiredstationaryengines;stationarygasturbines;ductburnersusedinturbineexhaustducts;lime,brick,andceramickilns;metallurgicalheattreatandreheatfurnaces;leadsmelting;reverberatoryandblastfurnaces;incinerators;glass,fiberglass,andmineralwoolprocessingfacilities;naturalgas-firedheaters,dryersandovens;andelectricitygenerationfacilities.TheDFWareahostsalloftheaboveequipment.HigherbackgroundozoneconcentrationsintheDFWareaareusuallyobservedwhenwindsoriginatefromthesouthandsoutheast,whilelowerconcentrationsareobservedwhenwindsoriginatefromthenorthandwest.Backgroundandtransportappearatthistimetoplayasecondary,thoughnotinconsequential,roleinDFWozonephotochemistry,atleastwhencomparedtolocalsources.However,thesesourcesmaycontributeagreaterfractionofthetotalinthefutureaslocalemissionsreductionsareimplemented.Meteorologyalsoaffectsotherkeyprocesses,suchaschemicalreactionrates(Banta,etal.,zooS).HighozoneconcentrationsareobservedmostfrequentlyintheDFWareaondayslackingstrongsynoptic,orlarge-scale,pressuregradients.Whensynoptic(large-scale)weathersystemsmovethroughtheregion,ozoneandprecursoremissionstendtobedilutedandcarriedoutofthecity,ratherthanconcentratedinstill,stagnatingair,tobeheated,reacted,andturnedintoozone.Daysdominatedbystrongsyrropticweathersystemstendtoexperiencelowozonelevels(Banta,etal',zoo5).Absentdominantsynopticweathersystems,smaller-scalelocalwindpatternsgovernozoneformation.Asprecursoremissionsareadvectedacrosstheregion,theymixwithotherlocalemissions,aswellascompoundstransportedintotheregion,togenerateelevatedconcentrationsofozone.Ondayswithlightwinds,precursorsgeneratedinthemorning,alongwiththoseremainingfromthepreviousday,accumulateandthenreactduringthewarmestandsunniestportionoftheday.OzonerichairmassesPage5typicallybegintoforminthecenterandsouthofthecity.Laterintheafternoon,southeasterlybreezescanadvect,orhorizontallytransport,thepoolofhighozoneoverthecitytowardthewestandnorthwest.Tosummarize,theDFWareaþpicallyexperienceshighozoneondaysthatarewarm,sunny,windseitherfromtheeastorsoutheast,orslowwindspeeds.ThismeansthatHoodandWiseCountiesareusuallydorr"nwindoftheDFWurbanplumeandunlikelytocontributetohighozonevaluesattheanalyzedozonemonitors.GiventheDFWarea'slargepopulation,automobilefleet,andvarietyofindustry,theareaproducesenoughemissionstoresultinahighozonedaywhenmeteorologicalconditionsarefavorable.AnalysisofEPA'sModelingforHoodandWiseCountiesTheEPAproposednonattainmentdesignationforHoodandWiseCountiesbasedontheirbeliefthattheemissionsfromthesecountiescontributetoobservedviolationsinthearea.ThissectiondescribeswhythetoolsusedbytheEPAarenotcapableofnorappropriateforprovidingsuchasdeterminationandthatthesecountiesdonotsignificantlycontributetothehighestozonelevels.TheEPAevaluatedavailablemeteorologicaldatatohelpdeterminehowmeteorologicalconditions,suchasweather,transportpatterns,andstagnationconditions,wouldaffectthefateandtransportprecursoremissionscontributingtoozoneformation.TheEPAusedtheNationalOceanicandAtmosphericAdministrationHybridSingleParticleLagrangianIntegratedTrajectory(NOAAHYSPLIT)Modelasitsprimarymodelingtool.ThisHYSPLITanalysisissimpleinnatureandisonlycapableofgivingaqualitativeexaminationofareasthatmayinfluencedesignvalueatkeyozonemonitoringsites.TheHYSPLITmodel,whichcreatesbacktrajectories,isnotcapableofdirectlylinkingozoneorpollutantsinoneareatoanother.HourlyendpointsarethehourlyestimatesofairparcellocationfromFfYSPLiTthatcomposeabacktrajectory,Thewholebacktrajectoryisthemean-pathofanairparceloverspaceandtime.Themodelusesmeteorologicaldatatoestimatehourlypositionsofwindparcelsinspaceandtime.Becausetheanalysesshowlargenumbersofbacktrajectoriesconvergingonasinglefixedpoint,themodelintroducesabuilt-inbias,whichtendstogivehigherendpointcountsinare¿isnearthereceptorsites,suchasanozonemonitor.TheEPA'sargumentdependshighlyonthepathatrajectorytookbeforereachingareceptorozonernonitor.Simplylookingatbacktrajectorieswhenthedailymaximumozoneisgreaterthan75paftsperbillion(ppb)willnotestablishthatthesetrajectoriesincreaseozonelevelsatanysingleozonemonitor.ToimproveuponEPA'sbacktrajectoryanalysis,theTCEQanalyzedbacktrajectoriesdevelopedbytheEPAtobetterunderstandtheeffectsofupwindregionsthatmayaffectozonemonitorsintheDFWarea.TheTCEQcreatedHYSPLITz4-hourbacktrajectoriesduringzoo6throughzoro.TheHYSPLITtrajectoriescoincidewithdayswhenmaximumdailyeight-hourozonewasgreaterthan75ppbintheDFWarea.ThesetrajectoriesareatBoometersinheight,wellwithinthemixinglayerduringtheday,butnottoolowthatthetrajectoriestouchgroundlevel,therebyinvalidatingthetrajectory.ThisanalysisbetterhighlightsthetrueextentoftrajectoriespassingthroughWiseandHoodCounties.TheanalysisusedthreeDFWozonemonitors,nameìyEagleMountain(Mtn.)Lake,KellerandParkerozonemonitoringsites.TheEPAusedastartingheightofroometers,whichoftenlefttrajectoriestouchinggroundlevelandcanresultinerroneousbacktrajectoriesovertime.ThebacktrajectoryhourlyendpointsgeneratedfromFIYSPLITwereplottedonamap.ThebacktrajectoryhourlyendpointsthatappearedoverHoodandWiseCountywerecounted.OnesetofbacktrajectoriesandhourlyendpointswereplottedforozonedesignvaluesensitivemonitorssuchastheParker,EagleMtn.LakeandKellerozonemonitors.AlowerfrequencyofendpointsindicateslessPage6probabilitythatanairparceltransportedozonefromHoodorWiseCountytoanozonemonitor.Therewereg,7gzendpointsgeneratedusingtheFrySPLITmodel.ResultsfromTCEQ'strajectoryanalysisshowg.7g%percentageofhourlyendpointsinWiseCountyareassociatedtotrajectoriesendingatEagleMtn.Lake(Figurer).AsmallerpercentageofhourlyendpointsinHoodCountyatr.og%wereattachedtotrajectoriesendingatEagleMtn.Lake(Figurez).BecauseEagleMtn.LakeisclosetoWiseCountyoneshouldexpecttoseehigherendpointcountsforWiseCounty.Furthermore,acloserexaminationofthesehourlyendpointsandtheirassociatedtrajectoriesshowsthatsometrajectoriesmeanderintoothercountiesbeforeterminatingatEagleMtn.Lake.AcursorycountofendpointsshowsthemajorityofendpointsarewithinTarrantCounty,EagleMtn.Lake'sresidingcounty.ThisisanupdateoftheanaþisnotedintheTCEQ'sJanuaryrL,2orz,responsetocommentletterthatstatedatmostonlyz.B7%ofthetrajectoryendpointsactuallytraverseWiseCounty.ThenumberofhourlyendpointsleadingtotheParkerCountyozonemonitorís3.9o%forWiseCounty(Figure3)andz.z7%forHoodCounty(Figure+).ThezorodesignvaluesettingmonitorfortheDFWareaisKeller.ThehourlyendpointcountforKelleris2.77%forWiseCounty(FigureS)ando.69%forHoodCounty(Figure6).TheTCEQnotedinitsJanuary!r,2or2,responsetocommentletterthatatmostonly265%ofthetrajectoryendpointsactuallytraverseHoodCounty.Thisslightrevisionistheresultoffurtherreviewoftrajectorydata.ThisbacktrajectoryanalysisindicatesthatwindseldompassesovereitherWiseorHoodCountybeforereachingozonemonitorsonhighozonedays.Theseanalyzesandthistool,however,donotindicateifHoodorWiseCountyemissionssignificantlycontributetoozoneformationattheseozonemonitors.Figure1:Themapshowstrajectoryendpoints(inred)inWiseCountyforreceptormonitorEagleMtn.Lake(5.75o/o).t.i.,,:l$r.afeûndpoiùtsateirìeo.WiseendpoirìlsPage7lti'..)"'.:lateli.riJfiËrì{lt!,;dsC{xr{{rlifIli:r!jO¿,.û.i.úí?ii-Tr¡¡!ilùtE¡,¡i:rríi{,ri,rllalrl(}.Hoodcor':Figure2:Themapshowstrajectoryendpo¡nts(inred)¡nHoodCountyforreceptormon¡torEagleMtn.Lake(1.O3o/o).Figure3:Themapshowstrajectoryendpoints(inred)¡nWiseCountyforreceptormon¡torParkerCounty(3.9oolo),åWlse'-i,,ir'i,;''ìl,;1..,r',,û16dolsHYSFLIT6rì¿poirìl$HoodlnaredolsendpoinlsA.rLi24TIYSiILITtrÉl!cLar;!3ãîC;r\1(f.irúili531¡6PageBCe.endpoin(sinHôódCú.afed9tshYSPLITdolsôte6ndpÕints221'hTtsj.dtìy¡;t\iï)plsii¡í)û,CaI"Figure4:Themapshowstrajectoryendpoints(inred)inHoodCountyforreceptormonitorParkerCounty(2.27o/o).Figure5:Themapshowstrajectoryendpoints(inred)inWiseCountyforreceptormonitorKeller(2.77o/o).Page9Figure6:Themapshowstrajectoryendpoints(inred)inHoodCountiesforreceptormonitorKeller(O.69olo).SupplernentalAnalysisonFactorsz:EmissionsandEmissionsRelatedDataand3:Meteorology(weather/transportpatterns)fortheDFWAreaTheTCBQutilizedanadditionalmodelingtool,ComprehensiveAirqualityModelwithextensions(CAMx)AnthropogenicPrecursorCulpabilityAssessment(APCA),ascomplementaryinformationtothemeteorologyandemissionsfactors.APCAisamodelingtoolthatcanbeusedtokeeptrackoftheoriginoftheNOxandVOCprecursorscreatingtheozoneatspecifiedlocationsduringamodelrun.Theozonecanthenbeapportionedtospecificuser-definedsourcesgroupsandregions.TheTCEQusedAPCAtodeterminetheeight-hourozonecontributionfromHoodandWiseCountiestospecificozonemonitorsintheDFWareaforzoo6andzot2.TheseAPCAlunsusedthesameJunezoo6episodemodelsetup(meteorology,emissions,CAMxversion,etc.)astheDallas-ForlWorthAttainmentDemonstrationsSIPRevisionfolthe1997Eight-HourOzoneStandardNonattainmentAreaadoptedDecember7,2orr(zouDFWADSIPRevision).TheJunezoo6episodewasshoumtoberepresentativeoftypicalozone-conduciveconditionsintheDtrWarea,includingimpactsfromlocalandnon-DFWsourceareasvlar¡nnddirectionsfromtheeast,southeast,andsouth.DetailsontheJunezoo6episodecanbefoundintheepisodeselectionoftheDFWmodelingprotocolatclf#p+le=gz.TheTCEQdidnotusetheupdatedoilandgassectorpneumaticemissionssubmittedOctober2011totheBPAforthePeriodicEmissionsInventoryinthismodelingandsourceapportionmentanalysis,therefore,theVOCemissionsfromthissourcecategoryarelikelyoverestimatedinthemodeling.Figure7,FigureB,andFigure9displaythezorecontributionstotheKeller,EagleMtn.Lake,andWeatherford(ParkerCounty)ozonemonitorsfromHoodCounty,WiseCounty,theinitialandboundaryconditions(IC/BC),andaliotherareasofthemodeleddomain,includingDFW(DFW+Other).ThemodeledJunezoo6episodeisshown.ThroughoutmostoftheepisodetheDFW+OtherandtheICIBCsourceregionsdominatethecontributionstototalpredictedozone.%oa.)t.Crâyd0tsáréHYSPLITendponrlsRe(ldotsâroondpoìrtsinHgqdÇo.'tt:.:.'PageroFigure7=2OL2FutureCaseKellerEight-HourOzoneAPCAResults2012l(ellerAPCAContribut¡ons20L2EagleMounta¡nLakeAPCAContributionsiWisoelkDl*01W,0(hi,iwtL/!(oa."ü-..sþ.".d'."e".¡¡-.*9.o'"ú".".."".$',,.$'.,,r'¡rþ.ef..s$.+þ."+h..o"-dþ...1þ.,jru..d'.,.f..¡i'"ou.+þ^+k.o(".r$.lÞ.¡1'¡t'.,*Srf,tù"ti'-".ñuf)o"'-o.r.st'"{,.'ñ.'-.'t',,f)'"r.1'J.,*"'n'"r¡'ño''",$t'"iy''"c"cd'*¡'s"'.rtrt'C'J,''"aÈ'.1+t'"t}'^+'Figure8:2O12FutureCaseEagleMtn.LakeEight-HourOzoneAPCAResultsçDFwr0rNerBIC/ãClc.0c¿c.ùl9ù.@."E.$9.^sú^o",".f,"y'.,.p"sou.sGp6,s+9ooo.o"""d,t-".t,"s..¡1".ñ.$".":0""ni".¡ñ¡f,",{.6nclc.nñ',4oc,.,ii'6tGne(o,f.,"'.r-,r+'"rñ.rt'"'pt'"sÛ"r"0"*s-"r.Ñ"r+g"r.l",--.r"C^'"o,'ÑCJ"--'.n''+rt'",:i'J'..f'"-''.rtt'",,"t'.n'"'ñ"t''¡o'Figure9=2OL2FutureCaseWeatherford(ParkerCounty)Eight-HourOzoneAPCAResults2012WeatherfordAPCAContributionsiwiscuHôodsOFW+Otlr¿rùlClBCo0.00-."".df.,rP"""',.ú"Sr."."é'..d...9'"e"^"sd."s","""',"ó9.ró"..."',"ô"."d,"s","s'',.dJ".d."s"",."ú,r""".o'.r"t".,f'"{n..""".,r'i'..ro'ñt'ñt'"'-t'ñt"ô"t'.$t'",-t'.r"t'*'.t'",'-'*'ù'.r-t'"t'-'"r"t"^"'aat'"r-*'*'^'"**'o;r'o1ù\',ilt'or.$'ntrl'"ttd"J".td'.t¡t.rst'^¡t"PagerrFigure10,Figure11,andFiguretzshowtheaverageandmaximumcontributionsfromHoodandWiseCountiestotheKeller,EagleMtn.Lake,andWeatherford(ParkerCounty)ozonemonitorsinzorz.TheICIBCandallotherareasofthemodeleddomain,includingDFW+Other,arealsorepresented.Thebluebarsexhibittheaveragecontributionforeight-hourozoneperiodsgreaterthanorequalto75ppb,whiletheredbarsexhibitthemaximumcontributionduringtheeight-hourozoneperiodsgreaterthanorequalto75ppbalthatozonemonitor.ThemaximafromHood,Wise,DFW+Other,andIC/BCsourceareascouldhaveoccurredondifferentdaysoreight-hourperiodsandthus,thesumofthemaximadoesnotcorrespondtothemodeleddesignvalueoranyspecificmaximumdailyeight-hourconcentration.TheaveragemodeledcontributionsofozonefromHoodCountyemissionstothethreeozonemonitorswerelessthano.rppb.TheaveragemodeledcontributionsofozonefromWiseCountyemissionswerelessthano.01attheKellermonitor.AttheEagleMtn.LakeandWeatherford(ParkerCounty)ozonemonitors,theaveragemodeledcontributionsofozonefromWiseCountyemissionswerelessthano.7ppb.Figure1O:2012ModeledOzoneContributionsatKeller2ALZKellerModeledContribution6s7s(ppb)forHours>75ppb59.90WAverrallcContril¡t¡tionWMaxirrunìContrìburtion23.241-9,L5ffi0.0r-0.020.010.03DFW{"ùthort-ìooclWiseIC/BCPagetzFigureLt=2OL2ModeledOzoneContributionsatEagleMtn.Lake20LZEagleMountainLalceModeled-Ç.qntribution(ppb)forHours>75ppb64.1857.67ffiAverrBcContrìbLrtionMMaxinrr¡rnContril¡ution23.7520.630,010.030.520.81-DFWi'Othcrl-lood!Viscrc/BCFiguret2=2OL2ModeledOzoneContributionsatWeatherford(ParkerCounty)åOLZWeatherford(ParkerCo.)ModeledContribution(ppb)for58.9561.76HOUfS>75ppbMAvcragccorrtributionWM¡xinLrnrConLr¡butiÒn1g.g520.220.030.160.61r,29Lü.,rffi#$tffiffiDFWtOthcrþloodWiScIC/BCAnotherbenefitoftheAPCAtoolisthatitdetermineshowNOxand/orVOCemissionscreateozonefromeachofthedefinedsourcecategoriesandregions.AttheWeatherford(ParkerCounty)ozonemonitorNOxemissionsfromHoodandWiseCountiescreatedg7-gg%ofthecontributedozonefromthesecounties,whileVOCemissionswereonlyresponsiblefort-g%ofthecontributedozonefromthesecounties.TheavailabilityofbiogenicVOCemissions,generallymorereactivethanlocalanthropogenicVOCemissions,mostlikelyinfluencestheimportanceofanthropogenicNOxemissions.UsingtheAPCAresults,contributionsfromHoodandWiseCountiestothezotzfuturedesignvaluesattheKeller,EagleMtn.Lake,andWeatherford(ParkerCounty)ozonemonitorswerecalculatedasshowninTable3.ThefractionsoftherelativeresponsefactorsfromHoodandWiseCountieswerePager3multipliedagainsttheobservedbaselinedesignvaluetodeterminethecontribution.AswiththezouDFWADSIPRevision,thismethodologyfollowedtheEPAmodelingguidanceforcalculatingafuturedesignvalue.Table3:ModeledOzoneContr¡but¡onstothe2012FutureDesignValueWeather{ord(ParkerCounty)BagleMtn.LakeKellerFutureFutureSourceRegionFutureContributionContributionContributionHoodCountyWiseCountyDFW+Otherrc/Bc0.08%0s3%76.52%22.86%0.0r%0.o1%78.O4%21,.93%7,25%1.25%73.L1%24.37%APCADVTtoo.o%1.00.0%100.0%NotsThèepCeDVrtotalmaynotequalthesumofthesoulceregioucontlibutionsduetorounding.AswiththeAPCAresultsshorvninTable3,thecontributionsfromHoodandWiseCountiestothezorzKellerfuturedesignvalue(DVr)areverysmall.AttheEagleMtn.LakeandWeatherford(ParkerCounty)ozonemonitors,thecontributionsarelargersincethoseozonemonitorsareclosertoHoodandWiseCounties.Thecontributionsarelessthanoneppb,whichindicatesthemajorityofthezorzdesignvaluecomesfromtheDFWareaandotherareasofthemodelingdomain.EvaluationoftheEPA'sFactor3:Meteorology(weather/transportpatterns)fortheHouston-Galveston-Brazoria(HGB)AreaCurrentUnderstandingofOzoneFormationintheHGBAreaOzoneformationintheHGBareaisgenerallyassociatedwithrelativelyclearskies,lightwinds,abundantsunshine,andtemperaturesaboveBotoBbdegreesFahrenheit.Typically,thesemeteorologicalconditionsareassociatedwithhighpressureareasthatmigrateacrosstheUnitedStatesduringthesummerseason.Andjustasimportant,precursorcompoundstoozoneneedtobepresentforozoneformation.Houstonhasallthesefactorsincludingthepresenceofmillionsofpeople,thepresenceofnumerousNOxandVOCemissionssources,andmeteorologicalconditionsfavorabletotheformationofozonefromthoseemissions.TheprocessesthatcreateemissionsintheHoustonareatypicallyarecontinuous,inlargeamounts,andpresenteveryday.Therefore,meteorologicalpatternsarethecontrollingforcethateitherdiluteandcarrypollutionoutofthecity(Banta,etal.,zoo5)orconcentratepollutioncausinghighozoneevents.Thisconcentrationofpollutionoremissionstypicallyistheresultoftheland-seabreezeflowreversalsandashorelineconvergencezone,whichcombinetoformarotationalwindpatternthatoftenrecirculatesemissionsoverozoneprecursorsources,amplifyingozoneformationdynamics(Banta,etal.,2oo5;Nielson-Gammonetal.,zoo5b).ResearchonthemeteorologyoftheHGBareahasfoundthatthehighestbackgroundozonetransportedintotheHGBareapredominatelyoriginatesfromthenorthandnortheast(Nielson-Gammonetal.,zoo5a).Similarly,atransportstudythatlinksmeasuredozonewithawinddirectionfoundthatwindsoriginatingfromthesouthtendtohavethelowestozoneconcentrations(Sullivan,zoog).Thehigherbackgroundconcentrationsareassociatedwithwindsthatoriginatefromthenortheast,eastor"short"trajectoriesthatrepresentstagnation.TrajectoriesfromthesouthwestarenotgenerallyassociatedwithhighbackgroundozonelevelsbeingtransportedintotheHGBnonattainmentarea.Paget4Morefundamentally,Houstonhasalargepopulationandemissionsthatarepresentonanygivenday.Meteorologicalpatternsofrecirculationarethedrivingforcethatdetermineswhetherozonetransportisasignificantfactorinozonedevelopment.Highbackgroundlevelsofozonecomefromtheeastandnortheast,notfromthesouthwestwhereMatagordaCountylies.Tosummarize,theEPAhasshovvnnosignificantorstatisticalbasistoexpectthatwindflowfromMatagordaCountyadverselyimpactstheHGBnonattainmentarea.Moreover,theTCEQ'sownanalysishasshor.r'njusthowinsignificantanypotentialcontributionfromMatagordaCountyreallyis.AnalysisofEPA'sModelingforMatagordaCountyTheEPAevaluatedavailablemeteorologicaldatatohelpdeterminehowmeteoroìogicalconditions,suchasweather,transportpatterns,andstagnationconditions,wouldaffectthefateandtransportprecursoremissionscontributingtoozoneformation.TheEPAusedtheNOAAFrySPLITModelasitsprimarymodelingtool.TheTCEQperformeditsownanalysisusingHYSPLITandconcludedthattheEPA'sconclusionsregardingpotentialtransportfromMatagordaCountyisunsupportable.ThekeytooltheEPAusedtoderiveitstransportargumentistheFIYSPLITmodel.Thebacktrajectorytoolsimplycalculatesairparcel'smean-pathmovementinspaceandtime.BoththeTCEQandBPAagreethatonlyafewtrajectoriestraverseMatagordaCountybeforereachingtheozonemonitorsintheHGBarea.ThedistinctionbetweentheEPAandTCEQpositionisthattheEPAfailstoshowonascientificorstatisticalbasisthatsuchasmallnumberoftrajectoriescouldadverselyaffecttheozonedesignvaluesattheseozonemonitoringsitesinparticularandtheHGBnonattainmentareaingeneral.TheEPAdoesnotpresentanyscientificorstatisticalevidencetosupportitsclaimofadverseimpactfromtransportnordoestheEPAquantifythenumberoftrajectoriespassingoverMatagordaCountyandhowmanywouldberequiredtocauseanoticeableorsignificanteffect.TheBPAalsolacksanycorroboratingevidence,suchasanozonemonitorinMatagordaCountytoshowthatthosetrajectoriesinquestionactuallycontainozone-orattheveryleastsufficientozonetoadverselyimpacttheHGBnonattainmentarea.ThiscannotbesufficienttoleadtheEPAtoconcludethattransportthroughMatagordaadverselyaffectstheHGBnonattainmentarea.FollowingEPA'sbacktrajectoryanalysis,theTCEQanalyzedbacktrajectoriestoshowthefrequencythatMatagordaCountywasupwindoftheozonemonitorsintheHGBarea.HYSPLITz4-hourbacktrajectorieswerecreatedforzoo6throughzoro.ThesetrajectoriesareatBoometersinheight,wellwithinthemixinglayerduringtheday,butnottoolowthatthetrajectoriestouchgroundlevel,therebyinvalidatingthetrajectory.TheEPA'suseoftoometerheighttrajectoriesistechnicallyfaulty.FurthermoretheseFrySPLITtrajectoriescoincidewithdayswhenmaximumdailyeight-hourozor,ewasgreaterthan75ppbintheHGBarea.TheTCEQ'sanalysisusedtrajectoriesterminatingatthreeHGBozonemonitoringsites,namelyManvelCroix,TexasCity,andWallisvilleRoad.PleasenotethattheWallisvilleozonemonitorisnotaregulatorymonitoranditwasusedintheTCEQ'sanalysisonlybecauseitwasusedbytheBPAintheirmodeling.Therewere4.z24hourlyendpointsgeneratedusingtheHYSPLITmodel.ThisanalysiswasconductedtohighlightthetrueextentofthenumberoftrajectoriespassingthroughMatagordaCounty.ToassesstheEPA'sHYSPLITanalysis,theTCEQdelineatedMatagordaCountyandthenoverlaidthetrajectories.Abacktrajectoryisthemean-pathofanairparceloverspaceandtime.Backtrajectoriesarecomposedofhourlypointsthattrackatrajectory'spathonanhourlybasis.TheManvelCroix,Wallisville,andTexasCityozonemonitorshadhourlyendpointsthatfellinMatagordaCountyandwerecounted.AlowerfrequencyofendpointsindicatesalowerprobabilitythatanairparceltransportedozonefromMatagordaCountytoanozonemonitor.Thisanalysisissimpleinnatureandisonlyintendedtogiveaqualitativeindicationofareasthatmayhavebeenupwindofdesignvaluesettingmonitors.AnimportantdistinctiorioftheHYSPLITmodel,whichcreatesthebacktrajectories,isthatitisnotintendedtodirectlylinkozoneorpollutantsinonePage15areatoanother.Themodelsimplyusesmeteorologicaldatatoestimatehourlypositionsofwindparcelsinspaceandtime.ResultsfortheWallisvilleozonemonitorshowthatveryfewhourlyendpointswerecontainedinMatagordaCounty,i.e.,o.4g%"(Figure13).TheTexasCityozonemonitorshowssimilarresultswitho.S7%(Figurer4),theNorthwestHarrisozonemonitorresultedino.9z%(Figurer5),andtheManvelCroixozonemonitorresultedintgo/"ofhourlyendpointsinMatagordaCounty(Figure16).TheTCEQnotedinitsJanuary7L,zoL2,responsetocommentletterthatatmostonlyr.B%ofthetrajectoryendpointsactuallytraverseMatagordaCounty.Thisslightrevisionistheresultoffurtherreviewoftrajectorydata.Therefore,MatagordaCountyemissionswouldrarelyhaveanopportunitytoimpactozonemonitorsbecausetheyareseldomupwindoftheozonemonitorsduringperiodsofeìevatedozone.Inaddition,thereareotheremissionsourcesbetweenMatagordaCountyandtheozonemonitors.Notethatlocallyproducedozonecanhavethegreatestimpactattheozonemonitor,especiallyinanareasuchasHouston,whichhasalargeautomobilefleet,isdenselypopulated,andishighlyindustrialized.Figure13:Mapshowshourlytrajectoryendpoints(inred)inMatagordaCountyfortheWallisvilleozonemonitor(O.43o/o).it:.tlrlå1ù{¡ordiÇp:'"^'-:-.,.(}r$yftût$iìrr,Jl..tyÊf:*lIf.ittú¡*tiìgimldoll;¡rrùy¡|riirrr;r($r,rl-.l.lrtalÇt¡:j.t:ì,.!{lj'ììi,íilit"!,it,ri¡)t!;:r.r.rt!¡t:t,!ì1?i.Þj,t^t:!?r.i;ìt3q,rjHít.!r:¿.:r'lììritì;lì,ìj,,rr:!:!,!.¿r,.;i:ar{ii,,i.r,rå,.*:,;lì,j,a"il..f.:-r,.i":.ìiÀii:-t..r^!ì.i.i;,:lr{ri.,jrl:iir¡Jfn.t.1¡Irfjf¡.t¡f,.1ì,.:,.ì¡r'ì.iir;ti.åt¡.li¡.r.,i:¿rt,rÌrri::rjr,rtri::r.ìri.1,lij.:it.i:¡1lt.ìtj,t..-,i,¡r',,¡èd'Page16Figure14:Mapshowshourlytrajectoryendpoints(inred)inMatagordaCountyfortheTexasCityozonemonitor(O.57o/o).1"..:l:t.l:tdtliiilrùlrYbi¡t-f{(ìrìÕilO(1ll;OilÈ.li*&Í(]p,i¡n{trnI'l'rlâû¡rC¡C-Ì,irrìi..¡,rìi-rjiri.:f,ri1..'ìr¡ji4il,!4:i/!1,,f,ií.r..,'."'iirfll,..,il::!i.1i,*:ì'I:ìr¡ir.il.;:¡l1i.1rù..1!ri¡r'jjl';lil,rji:i+îr.ftr(.rjji,/rt].1r.Jtn:\r,ìfr:1,!r:i:1,,...t..,,.r,:,,,,,...Figure15:Mapshowshourlytrajectoryendpo¡nts(inred)inMatagordaCountyfortheNorthwestHarrisozonemonitor(0.92olo).i#r*yNr.ñ'{t.{;:1.irl..j;1fdi..rì(l/rii.i:-tjirtirt,i:rrqllJi:¡;:j1;jl.):ìr¡,¡iìifìr,!irí.;iìí.rù31'1,:t,.:.:4:t'..1i,.iì,;-:..,ir'.7i!,r:1r.1li:t"ii'.ttt\,a:.,,.i't*,,1..{.n.1,¡:i¡tlr.'Page17Figure16:Mapshowshourlytrajectoryendpoints(inred)inMatagordaCountyfortheManvelCroixozonemonitor(1.9olo).Ms.!',,t.::...11.....Ì.]..',.-.J,l..i1:,.ltL,*¡,.1,;:**;!í1:,ìYÍj{}LlTl{r:rJdirlrt.u,:r!rÌí.Î¡r:¡rr$,';.',:tai.,)-]i.¿:.r.!rj.,,r,¡r.ijÌ,.rì1r:::.if:¡rJ:.1,,,n.-..-..^.+"----....--,-.--.,GiventhatthetrajectorycountisnotlargeatMatagordaCountyandtheEPAdoesnotpresentadditionalevidencetosupportthetransportofpollutantsorozone,thereisnotenoughevidencetosuggestthatMatagordaCountyadverselyaffectsozonedesignvaluesintheHGBarea.SupplementalAnalysisonFactorsz:EmissionsandEmissionsRelatcdDataand3:Meteorology(weather/transportpatterns)fortheHGBAreaTheEPAusedtheNOAAHYSPLITasitsprimarymodelingtool.TheTCEQutilizedanadditionalmodelingtool,APCA,ascomplementaryinformationonthemeteorologyandemissionsfactors.APCAisamodelingtoolthatcanbeusedtokeeptrackoftheoriginoftheNOxandVOCprecursorscreatingtheozoneatspecifiedlocationsduringamodelrun.Theozonecanthenbeapportionedtospecificuserdefinedsourcesgroupsandregions.TheTCEQusedAPCAtodeterminetheeight-hourozonecontributionfromMatagordaCountytospecificozonemonitorsintheHGBareaforzoo6andzor8,although2006datawillbethefocusofthisdocumentsinceeor8isseveralyearsfuture.TheseAPCArunsusedthesameepisodesandmodelsetup(meteorology,emissions,CAMxversion,etc.)astheHouston-Galveston-BrazoriaAttainmentDemonstrationStateImplementationPlanRevisionforthet997Eight-HourOzoneStandardadoptedMarch10,2o1o(zotoHGBADSIPRevision).Figuresr7andrBdisplaythezoo5andzoo6contributionsofozonefromMatagordaCountyemissionstotheManvelCroixozonemonitorandFigures19and20totheWallisvilleozonemonitor,respectively.AlsoshownaretheICIBCandallotherareasofthemodeleddomain,includingHGB+Other.Separatechartsareprovidedforthecollectivezoo5andzoo6episodes.Throughoutallepisodes,theHGB+OtherandtheICIBCsourceregionsdominatethecontributionstototalpredictedozone.Infact,itisdifficulttoseeanycontributionofozonefromMatagordaCountyemissionsatall.ChartswerealsodevelopedfortheNorthwestHarrisCountyozonemonitor(Figureszrandzz)andtheTexasCityozonemonitor(Figuresz3andz4),butcontributionsofozonefromMatagordaCountyemissionswereevenlessnotable.PagerBFigureL7=2OOSBaselineManvelCroixEight-HourOzoneAPCAResultsMACP20058-HourAPCA(MatagordaRun)120100¡eo@co80604070^80¡oo;60oo¿o5¡rot{zrPo!þlt'iþrt"!þrttþrzo$arr{¡zr{*l{zol{zzl{2atz00u5¡2en$zøPoiþ.rt$*r{æl2o0lrrrxo%plxooTprz0\plz0o5e!tclBcåSHGB+Other¡MatagordaFigure18:2OO6BaselineManvelCroixEight-HourOzoneAPCAResultsMACP20068-HourAPCA(MatagordaRun)200ssrcl8clr,{HGB+Other¡N¡atagorda120100u¡:rl{zt2o0f¡oroof¡erd*rr.þrzoþltþrtiir.ltiioru.þrt"þrr.þrz0$zrxo$arro$ortþrz.þrtiixrz$^rz$arr$rrroffçrzo6Page19Figure19:2005BaselineWallisvilleEight-HourOzoneAPCAResultsWALV20058-HourAPCA(MatagordaRun)I80604020720100Ièeocoou¡rur{*r0þt{'",t{rtr{.rrr{.rro%rrt{"el{zor2$zrr$rortoþrtoþrto!þrz$prtt!þrt"'?¡rlz0o5s¡rl2o0l¡rp00I¡tz006øtclBcãfHGB+Other¡MatâgordaFigure2O:2OO6BaselineWallisvilleEight-HourOzoneAPCAResultsWALV20068-HourAPCA(MatagordaRun)L20100^80oee;60o¿o20o,¡rrt2o0åztxooåapo.åorz""f¡orzoþrz.þrtþrt'iþrt'þrttþrt'þrr'þrr0$rrxo$arr$oru"þrz'|þrztiþrz$arz$orz$øltlffonoouNtclBc&HGB+OtherIMatagordaPagezoFigure21:2OO5BaselineNorthwestHarrisCountyEight-HourOzoneAPCAResultsHNWA20058-HourAPCA(MatagordaRun)qèaoo1201002080604020rt$*rr.$ær.þrtþrt$*r{irr{¡zt{"er2ooueport'þrt"oj*rt$*lr$*rz0116rz$2orlo!]ærxo%rrr?0%¡rlzo\¡stro\¡t2005MIC/BC!ñHGB+OtherIMatagordaFigure22:2OO6BaselineNorthwestHarrisCountyEight-HourOzoneAPCAResultsÌHNWA20068-HourAPCA(MatagordaRun)!20100^80!ooo60oo¿ou¡,,rxoof¡,r'ooånpooå.*-"ï:;'jÞr"iþr'"ii'.r"þ*'*TiJ:*.Ïzrz$ar{orzoþ""','*:i1'rz$ørz$øræfþrzo06PageztFigure23:2OO5BaselineTexasCityEight-HourOzoneAPCAResultsTXCT20058-HourAPCA(MatagordaRun)TXCT20068-HourAPCA(rVlaiaeorA"nun)720ã80ooo60cOao120100zo6rrclBcåãHGB+OtherIMâtagordaFigure24=2OO6BaselineTexasCityEight-HourOzoneAPCAResultsu¡rot{zlzo$*tt'þrt$rtr{1er{arPo%rrl{rrr{zorz0o.]*r"o$r^rz'$rorz""jptr{"orr$2trzo!]ærtoo!¡rPoo!plzo0!¡sl{¡lz0o5100_80¡oe;60oo¿o20u¡r't20$ztxooåorzooåordørzoþrz"þrz.þrtii*rt'þrztþrttþrz'þrz0$zrzo$orro$orttþrt"iþrt'iixrz$^rr$orx$etzoffrotzo06târclßcWHGB+OtherIMatagordaFiguresz5through32showtheaverageandmaximumcontributionsofozonefromMatagordaCountyemissionstotheManvelCroix,Wallisville,NorthwestHarrisCounty,andTexasCityozonemonitorsinzoo5and2c,c,6.TheIC/BCandallotherareasofthemodeleddomain,includingHGB+Other,arealsorepresented.Thebluebarsexhibittheaveragecontributionofozoneforeight-hourozoneperiodsgrãaterthanorequaltoZSppb,whiletheredbarsexhibitthemaximumcontributionofozoneduringiheeight-hourozoneperiodsgreaterthanorequalto75ppbatthatozonemonitor.ThemaximafromMatagorda,HGB+Other,andICIBCsourceareascouldhaveoccurredondifferentdaysoreight-hourperiodsandthus,thesumofthemaximadoesnotcorrespondtothemodeleddesignvalueoranyspecificmaximumdailyeight-hourconcentration.Ofalltheozonemonitoringsitesevaluated,theWallisvilleozonemonitorshowsthelargestaveragecontributionofozonefromemissionsourcecategoriesinMatagordaCounty,althoughthecontributionissmall(o.r8ppb).TheNorthwestHarrisCountyozonemonitorhadamodeledaveragecontributionofo.uppbfromMatagordaCountyemissions.PagezzFigure25:2OO5ModeledOzoneContributionsatManvelCroix2005MACPModeledContribution(ppb)forHours>75ppb97.38$iìAverageContr¡bution.qiiMâxìmumContribution70.1,1,26.13L5.840.040.4IHGB+OtherMatagordarclBCFigure2û2OO6ModeledOzoneContributionsatManvelCroix2006MACPModeledContribution(ppb)forHours>75ppb702.70wAverageContrìbution¡ffMaximumContribut¡on64.5329.3718.40Wo.101.05HGB+OtherMatagordatc/scPagez3Figure27:2OO5ModeledOzoneContributionsatWallisville2005WALVModeledContr¡bution(ppb)forHours>75ppb99.2LMAverageContribution&flMaximumContribut¡on70.680.090.44HGB+OtherMatagordatclBcFigure28:2OO6ModeledOzoneContributionsatWallisville2006WALVModeledContributionz+.sz(ppb)forHours>75ppb64.02¡:aAverageContribut¡onWMaximumContribution24.8r18.110.180.46HGB+OtherMatagordarclBc25.28r+.rzffiihffiffiPagez4Figure29:2OO5and2OO6ModeledOzoneContributionsatNorthwestHarrisCounty2005HNWAModeledContribution,r.ro(PPb)forHours>75PPb64.85MnAverageContribut¡on&3MaximumContribution27.L90.041,26WffiHGB+OtherMatagordaIC/BCFigure3O:2OO5and2OO6ModeledOzoneContributionsatNorthwestHarrisCounty2006HNWAModeledContributionzs.sr(ppb)forHours>75ppb63.37ä.1AverageContr¡but¡on$sMaximumContr¡bution2s.0818.010.111.86HGB+OtherMatagordaIC/BCPagez5Figure31:2OO5ModeledOzoneContributionsatTexasCity2005TXCTModeledContribution,r.r[RRb)forHours>75PPb63.89åaAverageContributionfiÍMaximumContribution24.4L17.280.050.2LHGB+OtherMatagordarclBcFigure32:2OO6ModeledOzoneContributionsatTexasCity2006TXCTModeledContributiong¡.zz(ppb)forHours>75ppbi*AverageContrìbut¡onKMaximumContribution29.8316.61O.rZ163HGB+OtherMatagordatc/BcUsingtheAPCAresults,contributionsfromMatagordaCountytothezor8futuredesignvaluesattheManvelCroix,NorthwestHarrisCounty,TexasCity,andWallisvilleozonemonitorswerecalculatedasshorvninTable4.ThefractionsoftherelativeresponsefactorsfromMatagordaCountywelemultipliedagainsttheobservedbaselinedesignvaluetodeterminethecontribution.Aswiththe2o1oADHGBSIPRevision,thismethodologyfollowedtheEPAmodelingguidanceforcalculatingafuturedesignvalue.Pagez6Table4:ModetedOzoneContributionstothe2018FutureDesignValueManvelNWI{arrisCroixWallisvilleCountvSourceResionTexasCitvMatagordaCountyHGB+Otherrc/Bc0.07%79.O4%20.88%0.23%80.5t%19.26%0.09%79,41%20.s0%0.06%81.24%L8.10%APCADVn100.00%rc0.00%100.00%1,oo.00%Note:TheAPCADVrtotalmaynotequalthesumofthesoulce}egioncont|ibutionsduetot'ounding.AswiththeAPCAresultsshowninFiguresz5through32,thecontributionsfromMatagordaCountytothezor8designvaluesareverysmall.Oftheozonemonitoringsitesevaluated,theWallisvilleozonemonitorreceivesthelargestcontributionofozonefromMatagordaCountyemissions,althoughevenitisexceedinglysmall(o.zoppb).AIìofthecontributionsofozonefromMatagordaCountyemissionsatthesemodeledmonitoringsitesaresignificantlylessthanrppb,whichindicatesthemajorityofthezor8designvaluecomesfromthenon-MatagordaCountyareasofthemodelingdomain.Basedontheseresults,thelikelihoodofozoneandozoneprecursorsfromMatagordaCountysignificantlyimpactingtheHGBozonedesignvaluesistoosmalltowarrantincludingMatagordaCountyintheHGBnonattainmentarea.Pagez7