Summary of the updated Regulatory Impact Analysis (RIA) for the Reconsideration of the 2008 Ozone National Ambient Air Quality Standard (NAAQS) pdf

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SummaryoftheupdatedRegulatoryImpactAnalysis(RIA)fortheReconsiderationofthe
2008OzoneNationalAmbientAirQualityStandard(NAAQS)
OnSeptember16,2009,EPAcommittedtoreconsideringtheozoneNAAQSstandard
promulgatedinMarch2008.TheozoneNAAQSwillbeselectedfromtheproposedrangeof
0.060to0.070ppm,basedonthisreconsiderationoftheevidenceavailableatthetimethelast
standardwasset.Today’sproposedrulealsoincludesaseparatesecondaryNAAQS,forwhich
thisRIAprovidesonlyqualitativeanalysisduetothelimitednatureofavailableEPAguidance
forattainingthisstandard
ThissupplementtotheRIAcontainsanupdatedillustrativeanalysisofthepotential
costsandhumanhealthandwelfarebenefitsofnationallyattaininga
newprimaryozone
standard.ThebasisforthisupdatedeconomicanalysisistheRIApublishedinMarch2008with
afewsignificantchanges.Thesechangesreflectthemorestringentrangeofoptionsbeing
proposedbytheAdministrator.Italsoreflectssomesignificantmethodologicalimprovements
toairpollutionbenefitsestimation,whichEPAhasadoptedsincetheozonestandardwaslast
promulgated.Thesesignificantchangesincludethefollowing:
 InMarch2008,theAdministratorloweredtheprimaryozoneNAAQSfrom0.084
ppmto0.075ppm.TheRIAwhichaccompaniedthatruleanalyzedalessstringent
alternativestandardof0.079ppm,andtwomorestringentstandardsof0.065and
0.070ppm.ThisRIAsupplementpresentsananalysisofthreealternativestandards
withintheproposedrange:0.060,0.065and0.070ppm.Becausetoday’sproposed
ruleisareconsideration,eachalternativestandardiscomparedagainsttheprior
standardof0.084ppm.PerExecutiveOrder12866andtheguidelinesofOMB
CircularA‐4,thisRegulatoryImpactAnalysis(RIA)alsopresentsanalysesoftwo
alternativestandards,0.075ppmand0.055ppm.Itisimportanttonotethatasthe
stringencyofthestandardsincreases,webelievethattheuncertaintyinthe
estimatesofthecostsandbenefitsalso
increases.Thisisexplainedinmoredetailin
sections2and3ofthissupplement.

 Wehaveadoptedseveralkeymethodologicalupdatestobenefitsassessmentsince
the2008OzoneNAAQSRIA.Theseupdateshavealreadybeenincorporatedinto
previousRIAsfortheproposedPortlandcementNESHAP,proposedNO
2
NAAQS,
andCategory3MarineDieselEngineRule,andarethereforenowincorporatedin
thisanalysis.Significantupdatesinclude:
o Weremovedtheassumptionofnocausalityforozonemortality,as
recommendedbytheNationalAcademyofScience(NAS).
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o Weincludedtwomoreozonemulti‐citystudies,perNASrecommendation.
o WerevisedtheValueofaStatisticalLife(VSL)tobeconsistentwiththevalue
usedincurrentEPAanalyses.
o Weremovedthresholdsfromtheconcentration‐responsefunctionsforPM
2.5
,
consistentwithEPA’sIntegratedScienceAssessmentforParticulateMatter.
StructureofthisUpdatedRIA
AspartoftheozoneNAAQSreconsideration,thisRIAsupplementtakesasits
foundationthe2008ozoneNAAQSRIA.Detailedexplanationofthemajorityofassumptions
andmethodsarecontainedwithinthatdocumentandshouldbereliedupon,exceptasnoted
inthissummary.
Thissupplementitselfconsistsoffourparts:
 Section1providesanoverviewofthechangestotheanalysisandsummarytablesof
theillustrativecostandbenefitsofobtainingarevisedstandardandseveral
alternatives.
 Section2containsasupplementalbenefitandcostanalysisforstandardalternatives
at0.055and0.060ppm.
 Section3containsasupplementalbenefitsanalysisoutliningtheadoptedchangesin

themethodology,updatedresultsforstandardalternatives0.065,0.070and0.075
ppmusingtherevisedmethodologyandassumptions.
 Section4containssupplementalevaluationofaseparatesecondaryozoneNAAQSin
therangeof7to15ppm‐hr,aswellasalessstringentof21ppm‐hr.This
supplementalprovidesanexplanationoftheextremedifficultyofquantifyingthe
costsandbenefitsofasecondarystandardatthistime.
S1.1ResultsofBenefit‐CostAnalysis
ThisupdatedRIAconsistsofmultipleanalyses,includinganassessmentofthenature
andsourcesofambientozone;estimatesofcurrentandfutureemissionsofrelevant
ozoneprecursors;airqualityanalysesofbaselineandalternativecontrolstrategies;
illustrativecontrolstrategiestoattainthestandardalternativesinfutureyears;
estimatesoftheincrementalcostsandbenefitsofattainingthealternativestandards,
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togetherwithanexaminationofkeyuncertaintiesandlimitations;andaseriesof
conclusionsandinsightsgainedfromtheanalysis.ItisimportanttorecallthatthisRIA
restsontheanalysisdonein2008;nonewairqualitymodelingorotherassessments
werecompletedexceptthoseoutlinedabove.
Thesupplementincludesapresentationofthebenefitsandcostsofattainingvarious
alternativeozoneNationalAmbientAirQualityStandardsintheyear2020.Theseestimates
onlyincludeareasassumedtomeetthecurrentstandardby2020.Theydonotincludethe
costsorbenefitsofattainingthealternatestandardsintheSanJoaquinValleyandSouthCoast
airbasinsinCalifornia,becauseweexpectthatnonattainmentdesignationsundertheCleanAir
Actfortheseareaswouldplacethemincategoriesaffordedextratimebeyond2020toattain
theozoneNAAQS.
InTableS1.1below,theindividualrowestimatesreflectthedifferentstudiesavailableto
describetherelationshipofozoneexposuretoprematuremortality.Thesemonetizedbenefits
includereducedhealtheffectsfromreducedexposuretoozone,reducedhealtheffectsfrom
reducedexposuretoPM
2.5

,andimprovementsinvisibility.Therangeswithineachrowreflect
twoPMmortalitystudies(i.e.PopeandLaden).
Rangesinthetotalcostscolumnreflectdifferentassumptionsabouttheextrapolation
ofcostsasdiscussedinChapter5ofthe2008OzoneNAAQSRIA.Thelowendoftherangeof
netbenefitsisconstructedbysubtractingthehighestcostfromthelowestbenefit,whilethe
highendoftherangeisconstructedbysubtractingthelowestcostfromthehighestbenefit.
Thepresentationofthenetbenefitestimatesrepresentsthewidestpossiblerangefromthis
analysis.
TableS1.2presentstheestimateoftotalozoneandPM
2.5
‐relatedprematuremortalities
andmorbiditiesavoidednationwidein2020asaresultofthisregulation.

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TableS1.1:TotalMonetizedCostswithOzoneBenefitsandPM
2.5
Co‐Benefitsin2020
(inBillionsof2006$)*

Ozone
Mortality
Function
Reference
TotalBenefits** TotalCosts*** NetBenefits
3% 7% 7% 3% 7%
0.075ppm
Multi‐city
Belletal.2004 $6.9to$15 $6.4to$13 $7.6to$8.8 $‐1.9to$7.4 $‐2.4to$5.4
Schwartz2005 $7.2to$16 $6.8to$13 $7.6to$8.8 $‐1.6to$8.4 $‐2.1to$5.4

Huang2005 $7.3to$16 $6.9to$13 $7.6to$8.8 $‐1.5to$8.4 $‐2.0to$5.4
Meta‐
analysis
Belletal.2005 $8.3to$17 $7.9to$14 $7.6to$8.8 $‐0.50to
$9.4 $‐1.0to$6.4
Itoetal.2005 $9.1to$18 $8.7to$15 $7.6to$8.8 $0.30to$10 $‐0.20to$7.4
Levyetal.2005 $9.2to$18 $8.8to$15 $7.6to$8.8 $0.40to$10 $‐0.10to$7.4
0.070ppm
Multi‐city
Belletal.2004 $13to$29 $11to$24 $19to$25 $‐12to$10 $‐14to$5.0
Schwartz2005 $15to$30 $12to$25 $19to$25 $‐10to$11 $‐13to$6.0
Huang2005 $15to$30 $13to$26 $19to$25 $‐10to$11 $‐12to$7.0
Meta‐
analysis
Belletal.2005 $18to$34 $16to$29 $19to$25 $‐7.0to$15 $‐9.0to$10
Itoetal.2005 $21to$37 $18to$31 $19to$25 $‐4.0to$18 $‐6.0to$12
Levyetal.2005 $21to$37 $18to$31 $19to$25 $‐4.0to$18 $‐6.0to$12

Multi‐city
Belletal.2004 $22to$47 $19 to$40 $32to$44 $‐22to$15 $‐25to$7.0
0.065ppm
Schwartz2005 $24to$49 $21to$42 $32to$44 $‐20to$17 $‐23to$9.0
Huang2005 $25to$50 $22to$42 $32to$44 $‐19to$18 $‐23to$10
Meta‐
analysis
Belletal.2005 $31to$56 $27to$48 $32to$44 $‐13to
$24 $‐17to$16
Itoetal.2005 $36to$61 $32to$53 $32to$44 $‐8.0to$29 $‐13to$20
Levyetal.2005 $36to$61 $32to$53 $32to$44 $‐7.0to$29 $‐12to$20
0.060ppm

Multi‐city
Belletal.2004 $35to$73 $30to$61 $52to$90 $‐55to$21 $‐60to$9.0
Schwartz2005 $39to$78 $34to$66 $52to$90 $‐51to$26 $‐56to$14
Huang2005 $41to$78 $35to$66 $52to$90 $‐49to$26 $‐55to$14
Meta‐
analysis
Belletal.2005 $53to$91 $46to$78 $52to$90 $‐37to
$39 $‐44to$26
Itoetal.2005 $63to$100 $55to$87 $52to$90 $‐27to$48 $‐35to$35
Levyetal.2005 $63to$100 $56to$87 $52to$90 $‐27to$48 $‐34to$35
0.055ppm
Multi‐city
Belletal.2004 $53to$110 $45to$90 $78to$130 $‐77to$32 $‐85to$12
Schwartz2005 $61to$120 $52to$100 $78to$130 $‐69to$42 $‐78to$22
Huang2005 $63to$120 $54to$100 $78to$130 $‐67to$42 $‐76to$22
Meta‐
analysis
Belletal.2005 $84to$140 $74to$120 $78to$130 $‐46to
$62 $‐56to$42
Itoetal.2005 $100to$160 $90to$140 $78to$130 $‐30to82 $‐40to$62
Levyetal.2005 $100to$160 $91to$140 $78to$130 $‐30to$82 $‐39to$62
*Allestimatesroundedtotwosignificantfigures.Assuch,theymaynotsumacrosscolumns.Onlyincludesareas
requiredtomeetthecurrentstandardby2020,doesnotincludeSanJoaquinandSouthCoastareasinCalifornia.
**Includesozonebenefits,andPM
2.5
co‐benefits.Rangewasdevelopedbyaddingtheestimatefromtheozone
prematuremortalityfunctiontoestimatesfromthePM
2.5
prematuremortalityfunctionsfromPopeetal.and
Ladenetal.Tablesexcludeunquantifiedandnonmonetizedbenefits.

***Rangereflectslowerandupperboundcostestimates.Dataforcalculatingcostsata3%discountratewasnot
availableforallsectors,andthereforetotalannualizedcostsat3%arenotpresentedhere.
Additionally,these
estimatesassumeaparticulartrajectoryofaggressivetechnologicalchange.Analternativestorylinemight
hypothesizeamuchlessoptimistictechnologicaltrajectory,withincreasedcosts,orwithdecreasedbenefitsin
2020duetoalaterattainmentdate.

S1‐5

TableS1.2:SummaryofTotalNumberofAnnualOzoneandPM
2.5
‐RelatedPremature
MortalitiesandPrematureMorbidityAvoided:2020NationalBenefits
A

CombinedEstimateofMortality 0.075ppm 0.070ppm 0.065ppm 0.060ppm 0.055ppm
NMMAPS
Belletal.(2004) 760 to 1,900 1,500 to 3,500 2,500 to 5,600 4,000 to 8,700 5,900 to 13,000
Schwartz 800 to 1,900 1,600 to 3,600 2,700 to 5 ,800 4,500 to 9,200 6,700 to 13,000
Huang 820 to 1,900 1,600 to 3,600 2,800 to 5,900 4,600 to 9,300 6,900 to 14,000
Meta‐analysis
Belletal.(2005) 930 to 2,000 2,000 to 4,000 3,500 to 6,600 6,000 to 11,000 9,400 to 16,000
Itoetal. 1,000 to 2,100 2,300 to 4,300 4,000 to 7,100 7,100 to 12,000 11,000 to 18,000
Levyetal. 1,000 to 2,100 2,300 to 4,300 4,100 to 7,200 7,100 to 12,000 12,000 to 18,000
CombinedEstimateofMorbidity 0.075ppm 0.070ppm 0.065ppm 0.060ppm 0.055ppm
AcuteMyocardialInfarction
B
 1,300 2,200 3,500 5,300 7,500
UpperRespiratorySymptoms
B

 9,900 19,000 31,000 48,000 69,000
LowerRespiratorySymptoms
B
 13,000 25,000 41,000 63,000 91,000
ChronicBronchitis
B
 470 880 1,400 2,200 3,200
AcuteBronchitis
B
 1,100 2,100 3,400 5,300 7,600
AsthmaExacerbation
B
 12,000 23,000 38,000 58,000 83,000
WorkLossDays
B
 88,000 170,000 270,000 420,000 600,000
SchoolLossDays
C
 190,000 600,000 1,100,000 2,100,000 3,700,000
HospitalandERVisits 2,600 6,700 11,000 21,000 35,000
MinorRestrictedActivityDays 1,000,000 2,600,000 4,500,000 8,100,000 13,000,000
A
Onlyincludesareasrequiredtomeetthecurrentstandardby2020,doesnotincludeSanJoaquin
ValleyandSouthCoastairbasinsinCalifornia.Includesozonebenefits,andPM
2.5
co‐benefits.Range
wasdevelopedbyaddingtheestimatefromtheozoneprematuremortalityfunctiontoboththelower
andupperendsoftherangeofthePM
2.5
prematuremortalityfunctionscharacterizedintheexpert

elicitationdescribedinChapter6ofthe2008RIA.
B
EstimatedreductioninprematuremortalityduetoPM
2.5
reductionsonly.
C
Estimatedreductioninprematuremortalityduetoozonereductionsonly.


Thefollowingsetofgraphsisincludedtoprovidethereaderwitharicherpresentation
oftherangeofcostsandbenefitsofthealternativestandards.Thegraphssupplementthe
tablesbydisplayingallpossiblecombinationsofnetbenefits,utilizingthesixdifferentozone
functions,thefourteendifferentPMfunctions,andthetwocostmethods.Eachofthe168bars
ineachgraphrepresentsaseparatepointestimateofnetbenefitsunderacertaincombination
ofcostandbenefitestimationmethods.Becauseitisnotadistribution,itisnotpossibleto
inferthelikelihoodofanysinglenetbenefitestimate.Thebluebarsindicatecombinations
wherethenetbenefitsarenegative,whereasthegreenbarsindicatecombinationswherenet
benefitsarepositive.FiguresS1.1throughS1.5showsallofthesecombinationsforall
standardsanalyzed.FigureS1.6showsthecomparisonoftotalmonetizedbenefitswithcosts
usingthetwobenefits
anchorpointsbasedonPope/Bell2004andLaden/Levy.
S1‐6

FigureS1.1:


FigureS1.2:

$(100)
$(80)

$(60)
$(40)
$(20)
$‐
$20
$40
$60
$80
$100
Billionsof2006$
Combin atio nsof6Ozonebenefitsestimateswith14PM
2.5
co‐benefitsestimateswith2costsestimates
NetBe nefitsforanAlternateStandardof0. 075pp m(7%discountrate)
Benefitsaregreaterthan
costs
Costsaregreaterthan
benefits
Median
=$3.1b
$(100)
$(80)
$(60)
$(40)
$(20)
$‐
$20
$40
$60
$80

$100
Billionsof2006$
Combination sof6Ozonebenefitsestimateswith14PM
2.5
co‐benefitsestimateswith2costsestimates
NetBenefitsforanAlternateStandardof 0.070ppm (7%discountrate)
Benefits aregreaterthan
costs
Costsaregreaterthan
benefits
Median
=$1.4b
Thesegraphsshowall168combinationsofthe6differentozonemortalityfunctionsandassumptions,the14differentPM
mortalityfunctions,andthe2costmethods.Thesecombinationsdonotrepresentadistribution.
S1‐7

FigureS1.3:

FigureS1.4:

$(100)
$(80)
$(60)
$(40)
$(20)
$‐
$20
$40
$60
$80

$100
Billion sof2006$
C ombinationsof6Ozonebenefitsestimateswith14PM
2.5
co‐benefitsestimateswith2costsestimates
NetBenefitsforanAlternateStandardof0.065ppm(7%discountrate)
Benefitsaregreaterthan
costs
Costsar egreaterthan
benefits
Median
=$0.7b
$(100)
$(80)
$(60)
$(40)
$(20)
$‐
$20
$40
$60
$80
$100
Billion sof2006$
Combination sof6Ozonebenefitsestimateswith14PM
2.5
co‐benefitsestimateswith2costsestimates
NetBenefitsforanAlternateStandardof0.060ppm(7%discountrate)
Benefitsaregreaterthan
costs

Costsar egreaterthan
benefits
Median
=$‐4.8b
Thesegraphsshowall168combinationsofthe6differentozonemortalityfunctionsandassumptions,the14differentPM
mortalityfunctions,andthe2costmethods.Thesecombinationsdonotrepresentadistribution.
S1‐8

FigureS1.5:



FigureS1.6:

$(100)
$(80)
$(60)
$(40)
$(20)
$‐
$20
$40
$60
$80
$100
Billionsof2006$
Combinationsof6Ozonebenefitses timateswith14PM
2.5
co‐benefitsestimateswith2costsestimates
NetBenefitsforanAlternateStandardof0.055ppm(7%discountrate)

Benefitsaregreaterthan
costs
Costsaregreaterthan
benefits
Median
=$‐2.8b
$0
$20
$40
$60
$80
$100
$120
$140
$160
0.075
ppm
0.070 
ppm
0.065 
ppm
0.060
ppm
0.055 
ppm
Billions of 2006$
Alternative Standard Level
ComparisonofTotalMonetizedBenefits toCos ts forAlternative
StandardLevelsin2020(Updatedresults,7%discountrate)
Thisgraphshowsall168combinationsofthe6differentozonemortalityfunctionsandassumptions,the14differentPM

mortalityfunctions,andthe2costmethods.Thesecombinationsdonotrepresentadistribution.
ThelowbenefitsestimateisbasedonPope/Bell2004andthehighbenefitsestimateisbasedonLaden/Levy.Thetwocostestimates
arebasedontwodifferentextrapolatedcostmethodologies.Theseendpointsrepresentseparateestimatesbasedonseparate
methodologies.Thedottedlinesareavisualcueonly,andtheselinesdonotimplyauniformrangebetweentheseendpoints.

S‐9

S1.2AnalysisoftheProposedSecondaryNAAQSforOzone
Exposurestoozonehavebeenassociatedwithawidearrayofvegetationand
ecosystemeffects,includingthosethatdamageorimpairtheintendeduseoftheplantor
ecosystem.Sucheffectsareconsideredadversetothepublicwelfare.

Today’sproposedrulecontainsacumulativeseasonalsecondarystandard,expressedas
anindexoftheannualsumofweightedhourlyconcentrations(usingtheW126form),setata
levelintherangeof7to15ppm‐hours,andrequestscommentonalevelof21ppm‐hours.
Theindexwould
becumulatedoverthe12‐hourdaylightwindow(8:00a.m.to8:00p.m.)
duringtheconsecutive3‐monthperiodduringtheozoneseasonwiththemaximumindexvalue
(hereafter,referredtoasthe12‐hour,maximum3‐monthW126).Forreasonsdetailedin
section4ofthissupplement,wewerenotabletocalculatemonetizedcostsandbenefitsof
attainmentoftheselevels.However,section4containsadetaileddiscussionoftherelevant
welfareeffects,andestimatesofthenumberofcountiesnationwidewhichwouldnotattain
eachalternativesecondaryNAAQS,bothcurrentlyandin2020.
S1.3 CaveatsandConclusions
Ofcriticalimportancetounderstandingtheseestimatesoffuturecostsandbenefitsis
thattheyarenotintendedtobeforecastsoftheactualcostsandbenefitsofimplementing
revisedstandards.Therearemanychallengesinestimatingthecostsandbenefitsofattaininga
tighterozonestandard,whicharefullydiscussed
in2008OzoneNAAQSRIAandthe
supplementtothisanalysisaccompanyingtoday’sproposedrule.

Theestimatedcostsandbenefitsofattainingalternateozonestandardsof0.060ppmor0.055
ppmarehighlyspeculativeandsubjecttolimitationsanduncertaintiesthatareuniquetothis
analysis. Wefirstsummarizethesekeyuncertainties:

 Theestimatednumberofpotentialnon‐attainmentareasisuncertain.Basedon
present‐dayozoneconcentrationsitisclearthatmanyareascurrentlyexceedtheozone
targetsof0.055and0.060.Itisalsoclearthattherewillbesubstantialimprovementsin
ozoneairqualitybetweennowand2020duetoexistingandrecentlypromulgated
emissionsreductionrules.Wehaveusedanairqualitymodeltoprojectozonelevelsin
2020basedoncertainestimatesofhowemissionswillincreaseordecreaseoverthat
timeperiod.Theseassumptionsaboutforecastedemissionsgrowthorreductionare










S‐10
highlyuncertainandwilldependuponeconomicoutcomesandfuturepolicydecisions.
Additionally,themethodologyforprojectingfuturenonattainmentreliesuponbaseline
observationsfromtheexistingozonemonitoringnetwork.Thisnetworkmaynot
includesomecountiesthateasilyattainhigherozonestandards,butmaynotattain
ozonestandardssofarbelowthecurrentNAAQS.Weestimatehumanhealthbenefits
byadjustingmonitoredozonevaluestojustattainalternatestandardlevels;wecan
onlyperformthisextrapolationincountiescontaininganozonemonitor.


 Thepredictedemissionreductionsnecessarytoattainthesetwoalternativestandards
arealsohighlyuncertain.BecausethehypotheticalRIAcontrolscenarioleftasignificant
portionofthecountryexceedingthe0.055and0.060targets,wehadtoextrapolatethe
rateofozonereductionseeninpreviousairqualitymodelingexercisestoestimatethe
additionalemissionsreductionsneededtomeetthelowertargets.Thedetailsofthe
approachareexplainedbelow,butformostareasoftheanalysisweusedsimpleimpact
ratiostoprojecttheozoneimprovementsasarateofNOxemissionsreduced.Useof
non‐site‐specific,linearimpactratiostodeterminethenon‐linear,spatially‐varying,
ozoneresponsewasanecessarylimitationwhichresultsinconsiderableuncertaintyin
theextrapolatedairqualitytargets.

 Thecostsofidentifiedcontrolmeasuresaccountsforanincreasinglysmallerquantityof
thetotalcostsofattainment.Thisisamajorlimitationofthecostanalysis.Weassume
amajorityofthecostsofattainingthetighteralternativestandardswillbeincurred
throughtechnologieswedonotyetknowabout.Thereforecostingfutureattainment
baseduponunspecifiedemissionreductionsisinherentlydifficultandspeculative.

Theuncertaintiesandlimitationssummarizedabovearegenerallymoreextensivethan
thoseforthe0.075ppm,0.070ppm,and0.065ppmanalyses.However,there
aresignificant
uncertaintiesinbothcostandbenefitestimatesforthefullrangeofstandardalternatives.
Belowwesummarizesomeofthemoresignificantsourcesofuncertaintycommontoalllevel
analyzedinthe2008ozoneNAAQSRIAandthissupplementalanalysis:

 Benefitsestimatesareinfluencedbyourabilitytoaccuratelymodelrelationships
betweenozoneandPMandtheirassociatedhealtheffects(e.g.,premature
mortality).
 Benefitsestimatesarealsoheavilydependentuponthechoiceofthestatistical
modelchosenforeachhealthbenefit.

S‐11
 PMco‐benefitsarederivedprimarilyfromreductionsinnitrates(associatedwith
NOxcontrols).Assuch,theseestimatesarestronglyinfluencedbytheassumption
thatallPMcomponentsareequallytoxic.Co‐benefitestimatesarealsoinfluenced
bytheextenttowhichaparticularareachoosestouseNOxcontrolsratherthan
VOCcontrols.
 Thereareseveralnonquantifiedbenefits(e.g.,effectsofreducedozoneonforest
healthandagriculturalcropproduction)anddisbenefits(e.g.,decreasesin
troposphericozoneleadtoreducedscreeningofUV‐Braysandreducednitrogen
fertilizationofforestsandcropland)discussedinthisanalysisinChapter6ofthe
2008OzoneNAAQSRIA.
 Changesinairqualityasaresultofcontrolsarenotexpectedtobeuniformoverthe
country.Inourhypotheticalcontrolscenariosomeincreasesinozonelevelsoccurin
areasalreadyinattainment,thoughnotenoughtopushtheareasinto
nonattainment
 AsexplainedinChapter5ofthe2008OzoneNAAQSRIA,thereareseveral
uncertaintiesinourcostestimates.Forexample,thestatesarelikelytousedifferent
approachesforreducingNOxandVOCsintheirstateimplementationplanstoreach
atighterstandard.Inaddition,sinceourmodelingofknowncontrolsdoesnotgetall
areasintoattainment,weneededtomakeassumptionsaboutthecostsofcontrol
technologiesthatmightbedevelopedinthefutureandusedtomeetthetighter
alternative.Forexample,forthe21counties(infourgeographicareas)thatarenot
expectedtoattain0.075ppm
1
in2020
2
,assumedcostsofunspecifiedcontrols
representasubstantialfraction,ofthecostsestimatedinthisanalysisrangingfrom
50%to89%oftotalcostsdependingonthestandardbeinganalyzed.
 AsdiscussedinChapter5ofthe2008OzoneNAAQSRIA,advicefromEPA’s

ScienceAdvisoryBoardhasquestionedtheappropriatenessofanapproach
similartooneofthoseusedhereforestimatingextrapolatedcosts.Forbalance,
EPAalsoappliedamethodologyrecommendedbytheScienceAdvisoryBoardin
aneffort
tobestapproximatethecostsofcontroltechnologiesthatmightbe
developedinthefuture.

1
Areasthatdonotmeet0.075ppmareChicago,Houston,theNortheasternCorridor,and
Sacramento.Formoreinformationseechapter4section4.1.1ofthe2008OzoneNAAQSRIA.
2
ThislistofareasdoesnotincludetheSanJoaquinandSouthCoastairbasinswhoarenot
expectedtoattainthecurrent0.084ppmstandarduntil2024.

S‐12
 Bothextrapolatedcostsandbenefitshaveadditionaluncertaintyrelativeto
modeledcostsandbenefits.Theextrapolatedcostsandbenefitswillonlybe
realizedtotheextentthatunknownextrapolatedcontrolsareeconomically
feasibleandareimplemented.Technologicaladvancesovertimewilltendto
increasetheeconomicfeasibilityofreducingemissions,andwilltendtoreduce
thecostsofreducingemissions.Ourestimatesofcostsofattainmentin2020
assumeaparticulartrajectoryofaggressivetechnologicalchange.This
trajectoryleadstoaparticularlevelofemissionsreductionsandcostswhichwe
haveestimatedbasedontwodifferentapproaches,thefixedcostandhybrid
approaches.Analternativestorylinemighthypothesizeamuchlessoptimistic
technologicalchangepath,suchthatemissionsreductionstechnologiesfor
industrialsourceswouldbemoreexpensiveorwouldbeunavailable,sothat
emissionsreductionsfrommanysmallersourcesmightberequiredfor2020
attainment,atapotentiallygreatercostperton.Underthisalternative
storyline,twooutcomesarehypotheticallypossible:Underonescenario,total

costsassociatedwithfullattainmentmightbesubstantiallyhigher.Underthe
secondscenario,statesmaychoosetotakeadvantageofflexibilityintheClean
AirActtoadoptplanwithlaterattainmentdatestoallowforadditional
technologiestobedevelopedandforexistingprogramslikeEPA’sOnroadDiesel,
NonroadDiesel,andLocomotiveandMarinerulestobefullyimplemented.If
statesweretosubmitplanswithattainmentdatesbeyondour2020analysis
year,benefitswouldclearlybelowerthanwehaveestimatedunderour
analyticalstoryline.However,inthiscase,statedecisionmakersseekingto
maximizeeconomicefficiencywouldnotimposecosts,includingpotential
opportunitycostsofnotmeetingtheirattainmentdate,whentheyexceedthe
expectedhealthbenefitsthatstateswouldrealizefrommeetingtheirmodeled
2020attainmentdate.Inthiscase,upperboundcostsare
difficulttoestimate
becausewedonothaveanestimateofthepointwheremarginalcostsareequal
tomarginalbenefitsplusthecostsofnonattainment.Clearly,thesecondstage
analysisisahighlyspeculativeexercise,becauseitisbasedonestimating
emissionreductionsandairqualityimprovementswithoutanyinformation

aboutthespecificcontrolsthatwouldbeavailabletodoso.
S2‐1

S2:SupplementalRegulatoryImpactAnalysisofAlternativeStandards
0.055and0.060ppmfortheOzoneNAAQSReconsideration

Synopsis

Thissupplementalchapterpresentsthecostsandbenefitsoftwoadditionalalternative
standards
1
,0.055ppmand0.060ppm.


S2.1 UncertaintiesandLimitations

Theestimatedcostsandbenefitsofattainingalternateozonestandardsof0.060ppmor
0.055ppmarehighlyspeculativeandsubjecttolimitationsanduncertaintiesthatareuniqueto
thisanalysis.Wefirstsummarizethesekeyuncertaintiesbeforedescribinghowbestto
interprettheseresults.

 Theestimatednumberofpotentialnon‐attainmentareasisuncertain.Basedon
present‐dayozoneconcentrationsitisclearthatmanyareascurrentlyexceedtheozone
targetsof0.055and0.060.Itisalsoclearthattherewillbesubstantialimprovementsin
ozoneairqualitybetweennowand2020duetoexistingandrecentlypromulgated
emissionsreductionrules.
2
Wehaveusedanairqualitymodeltoprojectozonelevelsin
2020basedoncertainestimatesofhowemissionswillincreaseordecreaseoverthat
timeperiod.Theseassumptionsaboutforecastedemissionsgrowthorreductionare
highlyuncertainandwilldependuponeconomicoutcomesandfuturepolicydecisions.
Additionally,themethodologyforprojectingfuturenonattainmentreliesuponbaseline
observationsfromtheexistingozonemonitoringnetwork.Thisnetworkmaynot
includesomecountiesthateasilyattainhigherozonestandards,butmaynotattain
ozonestandardssofarbelowthecurrentNAAQS.Weestimatehumanhealthbenefits
byadjustingmonitoredozonevalues
tojustattainalternatestandardlevels;wecan
onlyperformthisextrapolationincountiescontaininganozonemonitor.

 Thepredictedemissionreductionsnecessarytoattainthesetwoalternativestandards
arealsohighlyuncertain.BecausethehypotheticalRIAcontrolscenarioleftasignificant
portionofthecountryexceedingthe0.055
and0.060targets,wehadtoextrapolatethe


1
Forbenefitsresultsofthealternativestandardsanalysesfor0.065,0.070,and0.075,pleaseseeSection3ofthis
supplement.Forthecostresultsofthealternativestandardsanalysesfor0.065,0.070,and0.075,pleaseseethe
2008OzoneNAAQSRIA,whichcanbefoundat< />2
Thisimprovementinozoneairqualityisanticipateddespiteotherfactorsthatmayworsenozoneairquality,such
asincreasedpopulation,increasedtraffic,orotherfederalpolicies.
S2‐2

rateofozonereductionseeninpreviousairqualitymodelingexercisestoestimatethe
additionalemissionsreductionsneededtomeetthelowertargets.Thedetailsofthe
approachareexplainedbelow,butformostareasoftheanalysisweusedsimpleimpact
ratiostoprojecttheozoneimprovementsasarateofNOxemissionsreduced.Useof
non‐site‐specific,linearimpactratiostodeterminethenon‐linear,spatially‐varying,
ozoneresponsewasanecessarylimitationwhichresultsinconsiderableuncertaintyin
theextrapolatedairqualitytargets.

 Thecostsofidentifiedcontrolmeasuresaccountsforanincreasinglysmallerquantityof
thetotalcostsofattainment.Thisisamajorlimitationofthecostanalysis.Weassume
amajorityofthecostsofattainingthetighteralternativestandardswillbeincurred
throughtechnologieswedonotyetknowabout.Thereforecostingfutureattainment
baseduponunspecifiedemissionreductionsisinherentlydifficultandspeculative.

Theuncertaintiesandlimitationssummarizedabovearegenerallymoreextensivethan
thoseforthe0.075ppm,0.070ppm,and0.065ppmanalyses.Thetablebelowcontrastsour
levelofconfidenceineachofthekeyresults.

TableS2.1:Keyuncertaintiesandlimitationsintheanalysisfor
0.060ppmand0.055ppm
Analyticalquestion StandardAlternativesAnalyzed

0.055ppm&0.060ppm 0.065ppm,0.070ppm&
0.075ppm
Airqualityestimates 
Numberofcountiesattainingeachstandard
alternative
Medium Higher
Airqualityincrementnecessarytoattain
standard
Lower Medium
Costs 
Totalcostestimate Lower Medium
Distributionofcostsbysector Lower Medium
Levelofextrapolatedcosts Lower Medium
Benefits 
Sizeofozone‐relatedhumanhealthbenefits Lower Higher
SizeofPM
2.5
‐relatedhumanhealthco‐benefits Lower Higher
Distributionofbenefitsacrossthepopulation Lower Higher

Giventhepervasiveuncertaintiesinthe55ppband60ppbanalysis,thetypesof
conclusionsthatreadersmaydrawisnecessarilylimited.Conclusionsofthissupplemental
analysisareprovidedinSectionS2.6.

S2‐3

S2.2 EstimatingAQTargets

Themethodologyusedtodeveloptheestimatesofadditionalemissionsreductions
neededtomeetthe0.055ppmand0.060ppmstandardsisbasedonestimationtechniques

previouslysummarizedinthe2008OzoneNAAQSRIASection4.1,includingapplicationofthe
samecontrolmeasurereductionsandcosts.Theproceduresusedtoextendthatoriginal
analysistothetwolowerozonetargetsisexplainedbelow.

Ofthe659countiesthatarepartoftheanalysis,thereare565and385countiesthat
areprojectednottomeetthe0.055ppmand0.060ppmozonetargetsin2020,evenafter
implementationofthecontrolsinthehypotheticalRIAscenario.Asdescribedintheearlier
documentation,these“extrapolatedcontrolareas”wereseparatedintothreegroupsforthe
purposesofdeterminingwhatadditionalemissionsreductionswouldbenecessaryfor
projectedattainment.

Phase1areasweredefinedasthefourareaswiththelargestexpectedextrapolated
costs:SouthernCalifornia,westernLakeMichigan,Houston,andpartsoftheNortheast
Corridor.Fortheselocations,wehaveanavailablesetofsensitivitymodelingresultswhich
allowsforanassessmentoftheimpactsofadditionalNOxandNOx+VOCcontrolsofupto90
percentbeyondtheRIAcase.Unliketheoriginalanalysis,therewerenoareasforwhichan
equalcombinationofNOxandVOCcontrolswasdeterminedtobeamorecosteffectivecontrol
pathtoattainthelowerozonetargetsthanNOxcontrolexclusively.Therefore,forthis
supplementalanalysis,weassumedthatalladditionalextrapolatedemissionsreductionswould
comefromNOxcontrols.TableS2.2presentstheadditionalNOxreductionsestimatedtobe
neededtomeetthe0.055and0.060ppmtargets,aboveandbeyondthehypotheticalRIA
controlcase.Itshouldbenotedthatbecausethesensitivitymodelingdidnotconsidercontrols
beyonda
90percentreduction,itisnotpossibletoestimatethenecessary“extrapolatedtons”
foranyareathatdoesnotmeetthetargetinthesensitivitymodelingevenafter90percent
control.Theemissionstargetsfortheseareasaresimplylistedas“greaterthan90%”.

S2‐4

TableS2.2:EstimatedPercentageReductionsofNOxbeyondtheRIAControlScenario

NecessarytoMeettheSupplementalAnalysisTargetsinthePhase1Areas
0.055 0.060
Amador and Calaveras Cos., CA 0.071 65% 47%
Chico, CA 0.068 58% 37%
Imperial Co., CA 0.071 70% 51%
Inyo Co., CA 0.068 87% 56%
Los Angeles South Coast Air Basin, CA 0.122 > 90% > 90%
Mariposa and Tuolumne Cos., CA 0.072 72% 52%
Nevada Co., CA 0.075 74% 58%
Sacramento Metro, CA 0.080 82% 69%
San Benito Co., CA 0.066 54% 29%
San Diego, CA 0.076 80% 67%
San Francisco Bay Area, CA 0.069 64% 45%
San Joaquin Valley, CA 0.096 > 90% 87%
Santa Barbara Co., CA 0.068 55% 35%
Sutter Co., CA 0.067 56% 35%
Ventura Co, CA 0.077 73% 59%
Northeast Corridor, CT-DE-MD-NJ-NY-PA 0.077 > 90% 70%
Eastern Lake Michigan, IL-IN-WI 0.080 > 90% > 90%
Houston, TX 0.087 > 90% > 90%
Additional local control needed to
meet various standards
Phase 1 Area (NOx only)
2020 Design Value after RIA
Control Scenario (ppm)


Phase2areasweredefinedasanyareaoutsideaPhase1areawhoseprojected2020
designvalueexceeded0.070ppminthehypotheticalRIAscenario.Theimpactsofadditional
hypotheticalemissionsreductionsinupwindPhase1areaswereaccountedforinthe

calculationofneededextrapolatedtonsinPhase2areas.Afterthoseupwindreductionswere
accountedfor,weutilizedsimple“impactratios”(ppmimprovement/%emissionsreduced)to
determinetheremainingadditionalreductionsneededtomeetthe0.055and0.060ppm
targets.Asite‐specificimpactratiowasusedforeachPhase2areabasedonthelocalized
ozonechangesintheRIAcontrolscenariomodeling.TableS2.3presentstheextrapolated
percentreductionsestimatedforthePhase2areas.

S2‐5

TableS2.3:EstimatedPercentageReductionsofNOxbeyondtheRIAControlScenario
NecessarytoMeettheSupplementalAnalysisTargetsinthePhase2Areas


Allotherlocationsthatdidnotmeetthe0.055or0.060ppmtargetsafterthe2020RIA
controlscenariowereconsideredasaPhase3area.Ahighlysimplifiedapproachwasusedto
determine theextrapolatedtons neededintheseareas.First, insteadofexplicitly accounting
fortheimpactsofthe Phase1andPhase2upwind emissionsreductionsonPhase3areas,we
assumedthatthedesignvaluesfromthe60%NOxreductionrunweretheappropriatestarting
pointforestimatingtheadditionalemissionsreductionsinthePhase3areas.Sincethetargets
forthePhase1areasaregenerallygreaterthan60%andsincewe havenotaccountedforthe
Phase2reductions,theseestimatesshouldprovidea conservativeestimateofthepercentage
emissions reductions needed for full attainment.Secondly, we did not develop site‐specific
impactratiosforthe multiplePhase3areas.Instead,weusedastandardrelationshipof0.150
ppb / 1% NOx reduction for calculating the emissions reductions needed to attain 0.055 and
0.060 ppm in these areas.This value was the average site‐specific relationship calculated for
the Phase 2 areas, as described above.As a result of these assumptions, the estimated
emissions reductions needed to attain the supplemental standards in the Phase 3 should be
consideredtobehighlyuncertain.TheresultsofthePhase3analysisareshowninTableS2.4.
S2‐6




TableS2.4:EstimatedPercentageReductionsofNOxbeyondtheRIAControlScenario
NecessarytoMeettheSupplementalAnalysisTargetsinthePhase3Areas

S2‐7

S2‐8

 

FiguresS2.1andS2.2showwhichcountiesarepartoftheextrapolatedcostareasas
wellastheestimatedpercentreductionneededbeyondtheRIAcontrolcasetomeetthe
alternativestandardsof0.055and0.060ppmwithineachofthoseareas.Theconversionof
theseadditionalpercentagereductionstoactualextrapolatedtonsisdescribedinSectionsS2.3
ofthissupplement.
S2‐9

FigureS2.1:MapofExtrapolatedCostCountiesforthe0.055ppmAlternateStandardand
EstimatedPercentageNOxControlsNeededtoMeetthatStandardin2020


S2‐10

FigureS2.2:MapofExtrapolatedCostCountiesforthe0.060ppmAlternateStandardand
EstimatedPercentageNOxControlsNeededtoMeetthatStandardin2020


S2.3 EstimatingEmissionTargets


ThemethodologytodevelopairqualityNOxreductiontargetsforestimating
extrapolatedtonsreducedforthealternativestandardsispresentedinthe2008OzoneNAAQS
RIA
3
Section4.1.5.Nomethodologicalchangesweremadetoextendtheanalysistotargetsfor
the0.055ppmand0.060ppmalternativestandards.DiscussiononthecreationoftheNOx
targetsforthe0.055ppmand0.060ppmstandardsisinsectionS1.1.TheseNOxtargetswere
appliedtotheremainingemissionsfromtheRIAcontrolscenariobygeographicarea.Table
S2.5providestheextrapolatedreductionsbygeographicareaneededtoobtainthetwo
alternativestandardspost‐RIAcontrolscenarioemissions.TheextrapolatedNOxtonsare
obtainedbymultiplyingtheNOxtargetsinTablesS2.2throughS2.4bytheremainingemissions
for
eachareaaftertheRIAcontrolscenario.


3
 />S2‐11

Itisimportanttorepeatthattheextrapolatedcostareasarepotentiallystandard‐
specificbecausethelocationofcountiesinanextrapolatedareadependsonwhetherthe
particularstandardisbeingviolatedbyagreaterorlessernumberofmonitorsinthearea.For
example,asseeninFigures4.3aand4.3bofthe2008OzoneNAAQSRIA
3
theBoiseIdahoarea
extendsfurthereastforthe0.055ppmalternatestandardwhereareaslikeNewOrleans
attainedthe0.060standardbutnot0.055ppmalternatestandard.

TableS2.5:ExtrapolatedEmissionReductions(post‐RIAcontrolscenario)NeededtoMeet
the0.055ppmand0.060ppmAlternateStandardsin2020
a


ExtrapolatedCostArea AdditionalNOxEmissionReductionsNeeded
(annualtons/year)
0.055ppm 0.060ppm
Albuquerque,NM 7,800 3,100
Appleton‐Oshkosh,WI 3,600 
Atlanta,GA 140,000 80,000
Augusta,GA‐SC 4,900 
Austin,TX 41 
BatonRouge,LA 250,000 250,000
BentonHarbor,MI 3,500 200
BenzieCo,MI 1,800 
BerkeleyandJeffersonCounties,WV 1,200 
Birmingham,AL 72,000 17,000
Boise,ID 32,000 17,000
Boston‐Lawrence‐Worcester,MA 62,000 40,000
Buffalo‐NiagaraFalls,NY 50,000 35,000
Burlington,V
T
 3,100 
CampbellCo,WY 26,000 14,000
CanyonlandsNP 1,500 530
Carlsbad,NM 20,000 6,800
CedarCo,MO 1,400 2,200
CedarRapids,IA 160 
Charleston,WV 220 
Charlotte‐Gastonia‐RockHill,NC‐SC 210,000 150,000
Chattanooga,TN‐GA 12,000 1,600
Chico,CA 3,000 1,900
Cincinnati‐Hamilton,OH‐KY‐IN 110,000 59,000

ClearfieldandIndianaCos,PA 410 33
Cleveland,MS 180 
Cleveland‐Akron‐Lorain,OH 190,000 160,000
Clinton,IA 24,000 
CochiseCo,AZ 4,800 2,100
ColoradoSprings,CO 500 
Columbia,SC 24,000 8,700
CorpusChristi,TX 31,000 
Dallas‐FortWorth,TX 220,000 120,000
Davenport,IA 150 
Denver‐Boulder‐Greeley‐FtCollins‐Love., 80,000 43,000
Detroit‐AnnArbor,MI 180,000 180,000
S2‐12

ExtrapolatedCostArea AdditionalNOxEmissionReductionsNeeded
(annualtons/year)
0.055ppm 0.060ppm
ElPaso,TX‐NM 20,000 12,000
Eugene‐Springfield,OR 450 
Farmington,NM 86,000 52,000
FranklinCo,PA 630 100
GrandCanyonNP 22,000 1,800
GrandRapids,MI 90 
GreatBasinNP 470 
GreatSmokyMountainsNP 560 180
GreenBay,WI 420 11,000
Gulfport‐Biloxi,AL‐MS 25,000 6,600
Hancock,Knox,Lincoln&WaldoCo,ME 17,000 
Houston‐Galveston‐Brazoria,TX 260,000 310,000
Huntington‐Ashland,WV‐KY 170,000 100,000

HuronCo,MI 15,000 7,500
JeffersonCo,NY 26,000 17,000
JohnsonCity‐Kingsport‐Bristol,TN 45,000 21,000
KansasCity,MO‐KS 100,000 37,000
Knoxville,TN 22,000 9,200
LaCrosse,WI 290 
LakeCharles,LA 6,900 1,100
Lansing‐EastLansing,MI 1,900 
LasVegas,NV 23,000 14,500
LittleRock,AR 18,000 1,500
Longview,TX 950 360
LosAngelesSouthCoastAirBasin,CA
b
 270,000 230,000
Louisville,KY‐IN 59,000 29,000
Macon,GA 7,500 4,200
MadisonandPageCos(ShenandoahNP),VA 350 
McAlester,OK 800 
Medford,OR 5,200 300
Memphis,TN‐AR‐MS 160,000 98,000
MesaVerdeNP 4,600 390
Minneapolis‐St.Paul,MN‐WI 6,300 
Mobile,AL 25,000 9,900
Monroe,LA 9,300 
Muskegon,MI 160 
Nashville,TN 1,900 210
Natchez,MS 6 ,100 960
NevadaCo,CA 1,200 
NewOrleans,LA 2,800 
Newton,AR 2,300 

Norfolk‐VirginiaBeach‐NewportNews(HR) 130,000 79,000
NortheastCorridor,CT‐DE‐MD‐NJ‐NY‐PA 550,000 430,000
OklahomaCity,OK 18,600 
Omaha,NE‐IA 62,000 11,000
Orlando,FL 1,300 
Owensboro,KY‐IN 18,000 5,400
S2‐13

ExtrapolatedCostArea AdditionalNOxEmissionReductionsNeeded
(annualtons/year)
0.055ppm 0.060ppm
Paducah,KY‐IL 590 620
PanamaCity,FL 3,400 850
Parkersburg‐Marietta,WV‐OH 13,000 380
Pascagoula,MS 59,000 33,000
Pensacola,FL 24,000 10,000
Phoenix‐Mesa,AZ 51,000 28,000
Pittsburgh‐BeaverValley,PA 82,000 49,000
Portland,OR‐WA 37,000 11,000
Providence(AllRI),RI 310 
Raleigh‐Durham‐ChapelHill,NC 25,000 6,200
RapidCity,SD 4,400 700
Reno,NV 9,700 1,300
Richmond‐Petersburg,VA 30,000 15,000
Roanoke,VA 7,700 
RockyMount,NC 710 20
SacramentoMetro,CA 11,000 8,900
SaltLakeCity‐Ogden‐Provo,UT 43,000 24,000
SanAntonio,TX 39,000 19,000
SanJoaquinValley,CA

b
 180,000 150,000
SchoolcraftCo,MI 1,000 
Seattle,WA 98,000 48,000
Somerset,KY 450 
Spokane,WA 2 ,700 
Springfield,MO 90 
StLouis,MO‐IL 230,000 120,000
Steubenville‐Weirton,OH‐WV 260 
TampaBay‐St.Petersburg,FL 140,000 52,000
Toledo,OH 2,000 1,000
Tulsa,OK 130,000 55,000
Tupelo,MS 1,600 
Washington,DC‐MD‐VA 2,500 1,000
Waterloo,IA 19 
WesternLakeMichigan,IL‐IN‐WI 420,000 420,000
Wheeling,WV‐OH 130 
Wichita,KS 26,000 11,000
Williston,ND 620 
Wytheville,VA 240 
a
Estimatesareroundedtotwosignificantfigures.Assuch,totalswillnotsumdowncolumns.
b
TheLosAngelesSouthCoastAirBasinandSanJoaquinValleyareasofCAwillbereducingemissionstomeetthe
0.08ppmstandardintheyear2020.Theyareincludedinthisanalysisduetotheirinfluenceontheattainmentof
theSacramentogeographicarea.
