60318 federal register /vol. 62, no. 216/friday, november ... · pdf file60318 federal...

60318 Federal Register / Vol. 62, No. 216 / Friday, November 7, 1997 / Proposed Rules

ENVIRONMENTAL PROTECTIONAGENCY

40 CFR Part 52

[FRL–5911–7]

Finding of Significant Contribution andRulemaking for Certain States in theOzone Transport Assessment GroupRegion for Purposes of ReducingRegional Transport of Ozone

AGENCY: Environmental ProtectionAgency (EPA).ACTION: Notice of proposed rulemaking(NPR).

SUMMARY: In accordance with the CleanAir Act (CAA), today’s action is aproposed rulemaking to require certainStates to submit State implementationplan (SIP) measures to ensure thatemission reductions are achieved asneeded to mitigate transport of ozone(smog) pollution and one of its mainprecursors—emissions of oxides ofnitrogen (NOX)— across Stateboundaries in the eastern half of theUnited States. The States affected bytoday’s action are in the OzoneTransport Assessment Group (OTAG)Region.

Today’s action proposes to find thatthe transport of ozone from certainStates in the OTAG region (the 37eastern most States and the District ofColumbia) significantly contributes tononattainment of the ozone nationalambient air quality standards (NAAQS),or interferes with maintenance of theNAAQS, in downwind States. Thisproposal explains the basis fordetermining significant contribution orinterference with maintenance for theaffected States. Further, by today’saction, EPA is proposing the appropriatelevels of NOX emissions that each of theaffected States will be required toachieve.

The EPA is committed to promulgatefinal action on the proposed rule within12 months from the date of publicationof today’s action.DATES: The EPA is establishing a 120-day comment period, ending on March9, 1998. For additional information onthe comment period, please refer toSUPPLEMENTARY INFORMATION. A publichearing will be held during thecomment period, if requested. If apublic hearing is requested, EPA willmake an announcement in the FederalRegister.ADDRESSES: Documents relevant to thismatter are available for inspection at theAir and Radiation Docket andInformation Center (6101), Attention:Docket No. A–96–56, U.S.

Environmental Protection Agency, 401M Street SW, room M–1500,Washington, DC 20460, telephone (202)260–7548, between 8:00 a.m. and 4:00p.m., Monday through Friday, excludinglegal holidays. A reasonable fee may becharged for copying. Comments anddata may also be submittedelectronically by following theinstructions under SUPPLEMENTARYINFORMATION of this document. NoConfidential Business Information (CBI)should be submitted through e-mail.FOR FURTHER INFORMATION CONTACT:General questions concerning today’saction should be addressed to KimberSmith Scavo, Office of Air QualityPlanning and Standards, Air QualityStrategies and Standards Division, MD–15, Research Triangle Park, NC 27711,telephone (919) 541–3354. Please referto SUPPLEMENTARY INFORMATION belowfor a list of contacts for specific subjectsdescribed in today’s action.

SUPPLEMENTARY INFORMATION:

Comment PeriodBecause commenters may wish to

submit technical information that mayrequire additional time to develop, EPAwill accept additional pertinentinformation beyond the 120-day timeframe and will do what is possible totake the information into account for thefinal rulemaking. The EPA will makeevery effort to consider this information.However, due to the time framesassociated with this action, EPA cannotguarantee that information submittedafter the close of the comment periodwill be considered. The EPA iscommitted to publish the finalrulemaking within 12 months of thedate of today’s action.

Electronic AvailabilityThe official record for this

rulemaking, as well as the publicversion, has been established underdocket number A–96–56 (includingcomments and data submittedelectronically as described below). Apublic version of this record, includingprinted, paper versions of electroniccomments, which does not include anyinformation claimed as CBI, is availablefor inspection from 8 a.m. to 4 p.m.,Monday through Friday, excluding legalholidays. The official rulemaking recordis located at the address in ADDRESSESat the beginning of this document.Electronic comments can be sentdirectly to EPA at: [email protected]. Electroniccomments must be submitted as anASCII file avoiding the use of specialcharacters and any form of encryption.Comments and data will also be

accepted on disks in WordPerfect in 5.1file format or ASCII file format. Allcomments and data in electronic formmust be identified by the docket numberA–96–56. Electronic comments on thisproposed rule may be filed online atmany Federal Depository Libraries.

Availability of Related Information

Documents related to OTAG areavailable on the Agency’s Office of AirQuality Planning and Standards’(OAQPS) Technology Transfer Network(TTN) Bulletin Board System (BBS). Thetelephone number for the TTN BBS is(919) 541–5742. To access the bulletinboard a modem and communicationssoftware are necessary. The followingparameters on the communicationssoftware are required: Data Bits-8;Parity-N; and Stop Bits-1. Thedocuments are located on the OTAGBBS. The TTN can also be accessed viathe web at http://www.epa.gov/ttn. Ifassistance is needed in accessing thesystem, call the help desk at (919) 541-5384 in Research Triangle Park, NC.Other documents related to OTAG canbe downloaded from OTAG’s webpageat http://www.epa.gov/ttn/otag. TheOTAG’s technical data are located athttp://www.iceis.mcnc.org/OTAGDC.

For Additional Information

For technical questions related to thedetermination of significantcontribution, please contact NormPossiel, Office of Air Quality Planningand Standards, Emissions, Monitoring,and Analysis Division, MD–13,Research Triangle Park, NC 27711,telephone (919) 541–5692. For legalquestions, please contact HowardHoffman, Office of General Counsel, 401M Street SW, MC–2344, Washington,DC, 20460, telephone (202) 260–5892.For questions concerning the statewideemission budgets, please contact DougGrano, Office of Air Quality Planningand Standards, Air Quality Strategiesand Standards Division, MD–15,Research Triangle Park, NC 27711,telephone (919) 541–3292. For questionsconcerning SIP approvability, pleasecontact Carla Oldham, Office of AirQuality Planning and Standards, AirQuality Strategies and StandardsDivision, MD–15, Research TrianglePark, NC 27711, telephone (919) 541–3347. For questions concerning the costanalysis, please contact SamNapolitano, Office of AtmosphericPrograms, MC–6201J, 401 M Street SW,Washington, DC 20460, telephone (202)233–9751.

Outline

I. Preamble

60319Federal Register / Vol. 62, No. 216 / Friday, November 7, 1997 / Proposed Rules

A. Summary of Rulemaking and AffectedStates

B. General Factual BackgroundC. Statutory and Regulatory Background1. Clean Air Act Provisionsa. 1970 and 1977 Clean Air Act

Amendmentsb. 1990 Clean Air Act Amendmentsi. 1-hour Ozone NAAQSii. Revised Ozone NAAQSiii. Provisions Concerning Transport of

Ozone and Its Precursors2. Regulatory Structurea. March 2, 1995 Policyb. OTAGc. EPA’s Transport SIP Call Regulatory

Effortsd. Revision of the Ozone NAAQSe. Impacts of NOX EmissionsD. EPA’s Proposed Analytical Approach1. Process for Requiring Submission of

Section 110(a)(2)(D) SIP Revisions2. Overview of Elements of Section

110(a)(2)(D)a. Summary of Section 110(a)(2)(D)b. Significant Contribution to

Nonattainmentc. Interfere with Maintenanced. Remedying the Significant Contributioni. Adequate Mitigationii. Elimination of Contributioniii. Comparison of the Two Legal

Interpretations of Section 110(a)(2)(D)iv. Other Issuese. Control Implementation and Budget

Attainment DatesE. Section 126 PetitionsF. OTAG Process

II. Weight of Evidence Determination ofSignificant Contribution

A. IntroductionB. Background Technical Information1. OTAG Modeling Process2. OTAG Strategy Modeling3. OTAG Geographic Modeling4. Other Relevant AnalysesC. Technical Analyses of Significant

Contribution1. Criteria for Determining Significant

Contribution2. Overview of Technical Approach3. Identification of Ozone ‘‘Problem Areas’4. Analysis of Air Quality, Trajectory, and

Non-OTAG Modeling Information5. Approaches for Analyzing Subregional

Modeling Dataa. Approaches for 1-Hour Nonattainmentb. Approaches for 8-Hour Nonattainmentc. Methods for Presenting 1-Hour and 8-

Hour Assessments6. Contributions to 1-Hour Nonattainment7. Contributions to 8-Hour Nonattainment8. Assessment of State ContributionsD. Comparison of Upwind and Downwind

Contributions to Nonattainment andCosts of Controls

III. Statewide Emissions BudgetsA. General Approach for Calculating

Budgets1. Overview2. Relationship of Proposed Budget

Approach to the OTAGRecommendations

3. Uniform Application of ControlMeasures

a. OTAG

b. Collective Contribution and EquityConsiderations

c. Modeling Assumptions and PotentialSynergistic Effects

d. Electrical Generation and EmissionsShifting

e. Alternative Approaches Based on Non-Uniform Application of ControlMeasures

4. Seasonal vs Annual Controls5. Consideration of Areas with CAA

Section 182(f) NOX Waivers6. Relation of OTC NOX MOU to Budgets

in the Ozone Transport SIP RulemakingB. Budget Development Process1. Overview2. Description of and Rationale for

Proposed Control Assumptionsa. Considering the Cost Effectiveness of

Other Actionsb. Determining the Cost Effectiveness of

NOX Controlsc. Summary of Measures Assumed in

Proposed Budget Calculation3. Proposed Assumptions for Electric

Utilitiesa. Affected Entitiesb. Methodology Used to Determine the

Proposed Electric Utility BudgetComponent

i. Proposed Utility Budget ComponentCalculation and Alternatives

ii. Seasonal Utilizationiii. Growth Considerationsc. Summary and Proposed Utility Budget

Components4. Proposed Assumptions for Other

Stationary Sourcesa. Affected Entitiesb. Methodology Used to Determine the

Proposed Area and Nonutility PointSource Budget Components

c. Summary and Proposed Area andNonutility Point Source BudgetComponents

5. Proposed Assumptions for HighwayVehicles

a. Affected Entitiesb. Methodology Used to Develop the

Proposed Highway Vehicle BudgetComponent

i. Budget Component DeterminationMethod and Alternatives Considered

ii. Activity Level Projections and GrowthConsiderations

iii. Seasonal/Weekday/WeekendAdjustment

iv. Comparison to OTAGRecommendations

c. Summary and Proposed HighwayVehicles Budget Components

d. Conformity6. Proposed Assumptions for Nonroad

Sourcesa. Affected Entitiesb. Methodology Used to Determine the

Proposed Nonroad Budget Componenti. Budget Component Determination

Method and Alternatives Consideredii. Activity Level Projections and Growth

Considerationsiii. Seasonal/Weekday/Weekend

Adjustmentiv. Comparison to OTAG

Recommendationsc. Summary and Proposed Nonroad Budget

Components

C. State-by-State Emissions BudgetsD. Recalculation of Budgets

IV. Implementation of Revised Air QualityStandards

A. IntroductionB. BackgroundC. Implementation Policy1. Areas Eligible for the Transitional

Classification2. Areas Not Eligible for the Transitional

ClassificationV. SIP Revisions and Approvability Criteria

A. SIP Revision Requirements andSchedule

B. SIP Approval Criteria1. Budget Demonstration2. Control Strategiesa. Enforceable Measures Approachb. Fixed Tonnage Budgets3. Control Strategy Implementation4. Growth Estimates5. Promoting End-Use Energy EfficiencyC. Review of ComplianceD. 2007 Reassessment of TransportE. Sanctions1. Failure to Submit2. Failure to ImplementF. Federal Implementation Plans (FIPs)1. Legal Framework2. Timing of FIP Action3. Statewide Emissions Budgets4. FIP Control Measures5. FIP Trading Program6. Section 105 GrantsG. Other Consequences

VI. States Not Covered by This RulemakingVII. Model Cap-and-Trade ProgramVIII. Regulatory AnalysisIX. Air Quality AnalysesX. Nonozone Benefits of NOX ReductionsXI. Impact on Small EntitiesXII. Unfunded Mandates Reform ActAppendix A—ReferencesAppendix B—OTAG RecommendationsAppendix C—Tables for Section II. Weight of

EvidenceDetermination of Significant ContributionAppendix D—Figures for Section II. Weight

of EvidenceDetermination of Significant Contribution

I. Preamble

A. Summary of Rulemaking andAffected States

The CAA has set forth manyrequirements to address nonattainmentof the ozone NAAQS. Many States havefound it difficult to demonstrateattainment of the NAAQS due to thewidespread transport of ozone and itsprecursors. The Environmental Councilof the States (ECOS) recommendedformation of a national work group toallow for a thoughtful assessment anddevelopment of consensus solutions tothe problem. This work group, OTAG,was established 2 years ago to undertakean assessment of the regional transportproblem in the Eastern half of theUnited States. The OTAG was acollaborative process conducted byrepresentatives from the affected States,EPA, and interested members of the


public, including environmental groupsand industry, to evaluate the ozonetransport problem and developsolutions. The OTAG region includesthe following 37 States and the Districtof Columbia: Alabama, Arkansas,Connecticut, Delaware, District ofColumbia, Florida, Georgia, Illinois,Indiana, Iowa, Kansas, Kentucky,Louisiana, Maine, Maryland,Massachusetts, Michigan, Minnesota,Mississippi, Missouri, Nebraska, NewHampshire, New Jersey, New York,North Carolina, North Dakota, Ohio,Oklahoma, Pennsylvania, Rhode Island,South Carolina, South Dakota,Tennessee, Texas, Vermont, Virginia,West Virginia and Wisconsin. Today’saction builds on the work of OTAG.

Through the OTAG process, the Statesconcluded that widespread NOX

reductions are needed in order to enableareas to attain and maintain the ozoneNAAQS. The EPA believes, based ondata generated by OTAG and other datasources, that certain downwind Statesreceive amounts of transported ozoneand ozone precursors that significantlycontribute to nonattainment in thedownwind States. Today’s actionproposes SIP requirements undersection 110(a)(1) and section 110(k)(5)in order to meet the requirements ofsection 110(a)(2)(D) to prohibit ozoneprecursor emissions from sources oractivities in those States from‘‘contribut(ing) significantly tononattainment in, or interfer(ing) withmaintenance by,’’ a downwind State ofthe ozone NAAQS.

Upon this determination, the EPA isrequiring SIP revisions in order to takesteps toward ensuring that the necessaryregional reductions are achieved thatwill enable current ozonenonattainment areas in the eastern halfof the United States to prepareattainment demonstrations and that willenable all areas to demonstratenoninterference with maintenance ofthe ozone standard.

The OTAG’s July 8, 1997 finalrecommendations (see Section I.F.OTAG Process and Appendix B)identify control measures for States toachieve additional reductions inemissions of NOX and do not identifysuch measures for volatile organiccompounds (VOC) beyond EPA’spromulgation of national VOCmeasures. The OTAG Regional andUrban Scale Modeling and Air QualityAnalysis Work Groups reached thefollowing relevant conclusions:

• Regional NOX emissions reductionsare effective in producing ozonebenefits; the more NOX reduced, thegreater the benefit.

• VOC controls are effective inreducing ozone locally and are mostadvantageous to urban nonattainmentareas. (See Appendix B).

The EPA agrees with these OTAGconclusions and, thus, is not proposingnew SIP requirements for VOCemissions for the purpose of reducingthe interstate transport of ozone. Statesmay, however, need to consideradditional reductions in VOC emissionsas they develop local plans to attain andmaintain the ozone standards.

Therefore, this rulemaking is intendedto make a finding of significantcontribution to a nonattainmentproblem, or interference with amaintenance problem, and to assign,specifically, the emissions budgets forNOX that each of the identified Statesmust meet through SIP measures. Asindicated, the EPA is proposing torequire the submission of SIP controls tomeet the specified budgets. However,this requirement permits each State tochoose for itself what measures to adoptto meet the necessary emission budget.Consistent with OTAG’srecommendations to achieve NOX

emission decreases primarily from largestationary sources in a trading program,EPA encourages States to considerelectric utility and large boiler controlsunder a cap-and-trade program as a cost-effective strategy. This is described inmore detail in section III, StatewideEmission Budgets. The EPA alsorecognizes that promotion of energyefficiency can contribute to a cost-effective strategy. The EPA is working todevelop guidance on how States canintegrate energy efficiency into theirSIPs to help meet their NOX budgets atleast cost.

The EPA proposes to find, afterconsidering OTAG’s recommendationsand other relevant information, that thefollowing 22 States and the District ofColumbia significantly contribute tononattainment in, or interfere withmaintenance by, a downwind State:Alabama, Connecticut, Delaware,Georgia, Illinois, Indiana, Kentucky,Massachusetts, Maryland, Michigan,Missouri, North Carolina, New Jersey,New York, Ohio, Pennsylvania, RhodeIsland, South Carolina, Tennessee,Virginia, West Virginia, and Wisconsin.These findings proposed today reflectthe air quality modeling and othertechnical work done by OTAG, as wellas other relevant information.

Under this proposal, these Stateswould be required to adopt and submit,within 12 months after publication ofthe notice of final rulemaking, SIPscontaining control measures that willmitigate the ozone transport problem bymeeting the assigned statewide

emissions budget. Section II, Weight ofEvidence Determination of SignificantContribution, describes how EPAdetermined which States to propose assignificant contributors, and section III,Statewide Emission Budgets, describeshow EPA determined the appropriatestatewide emission budgets andproposes to assign specific emissionbudgets for the States identified above.Section V, SIP Revisions andApprovability Criteria, describes theproposed SIP requirements.

The EPA believes that expeditedimplementation of regional controlstrategies to facilitate attainment isnecessary. On July 18, 1997, EPApublished its final rule for strengtheningthe NAAQS for ozone by establishing anew, 8-hour NAAQS (62 FR 38856).This results in more areas and largerareas with monitoring data indicatingnonattainment. Thus, it will be evenmore critical to implement regionalcontrol strategies which will mitigatetransport into areas in violation of thenew standard and thus enable theseareas to demonstrate attainment. Theregional NOX reduction strategyproposed in today’s action will providea mechanism to achieve reductions thatwill be necessary for States to enablethem to attain and maintain this revisedstandard. The proposed regionalreductions alone should be enough toallow most of the new nonattainmentcounties in States covered by thisrulemaking to be able to comply withthe new standard. States that are notrequired to comply with therequirements set forth in today’s actionwould also benefit from the NOX

strategy EPA is proposing if they adoptsimilar measures. On July 16, 1997,President Clinton issued a directive onthe implementation of the revised airquality standards. This implementationpolicy is described in section IV,Implementation of Revised Air QualityStandards.

Many of the States that EPA is notproposing to find as significantcontributors to the ozone nonattainmentproblem, and, therefore, do not have aproposed NOX statewide emissionsbudget to mitigate ozone transport, stillmay need, as recommended by OTAG,to cooperate and coordinate SIPdevelopment activities with otherStates. States with local interstatenonattainment areas for the 1-hourstandard and/or the new 8-hourstandard are expected to work togetherto reduce emissions to mitigate localscale interstate transport problems inorder to provide for attainment in thenonattainment area as a whole.

In addition, areas in these States(those covered by OTAG modeling but


not covered by this proposal) may beable to receive the transitionalclassification as described in section IV,Implementation of Revised Air QualityStandards. An area in the State wouldsatisfy one of the eligibilityrequirements for the transitional areaclassification by attaining the 1-hourstandard and submitting a SIPattainment demonstration by 2000 forthe 8-hour standard. The OTAG’smodeling (in particular, OTAG strategyRun 5 described in section II.B.2, OTAGStrategy Modeling) shows that a strategyin which a State adopted NOX emissiondecreases similar to those EPA proposesto establish in this rulemaking would behelpful in achieving attainment in mostof these areas. The EPA stronglysuggests that these States (those coveredby OTAG modeling but not covered bythis proposal) with new nonattainmentcounties for the 8-hour standard shouldconsider the option of this strategy sinceour analysis indicates that nearly allnew nonattainment counties areprojected to come into attainment as aresult of this strategy. The benefits ofthis regional strategy for States notrequired to implement the proposedstrategy under this rulemaking aredescribed below in section VI, StatesNot Covered by this Rulemaking.

The EPA plans to publish asupplemental notice of proposedrulemaking (SNPR) in early 1998. TheAgency intends to include in the SNPRa proposed model cap-and-trade rule,air quality analyses of the proposedstatewide emission budgets, emissionsreporting and State reportingrequirements, a discussion of theinteraction with the Title IV NOX rule(including EPA’s plans to proceed withrulemaking on remanded elements ofthat rule relating to flexibleimplementation where an appropriatecap-and-trade system is in place), andproposed rule language for therulemaking discussed in today’s action.There will be another public commentperiod following publication of theSNPR. All comments received regardingeither today’s action or the proposedrule language in the SNPR will beconsidered before promulgation of afinal rule.

B. General Factual BackgroundIn today’s proposal, EPA takes a

significant step in order to reduce ozonein the eastern half of the country.Ground-level ozone, the main harmfulingredient in smog, is produced incomplex chemical reactions when itsprecursors, VOC and NOX, react in thepresence of sunlight. The chemicalreactions that create ozone take placewhile the pollutants are being blown

through the air by the wind, whichmeans that ozone can be more severemany miles away from the source ofemissions than it is at the source.

At ground level, ozone can cause avariety of ill effects to human health,crops and trees. Specifically, ground-level ozone induces the following healtheffects:

• Decreased lung function, primarilyin children active outdoors.

• Increased respiratory symptoms,particularly in highly sensitiveindividuals.

• Hospital admissions and emergencyroom visits for respiratory causes,among children and adults with pre-existing respiratory disease such asasthma.

• Inflammation of the lung.• Possible long-term damage to the

lungs.The new 8-hour primary ambient air

quality standard will provide increasedprotection to the public from thesehealth effects.

Each year, ground-level ozone abovebackground is also responsible forseveral hundred million dollars worthof agricultural crop yield loss. It isestimated that full compliance of thenewly promulgated ozone NAAQS willresult in about $500 million ofprevented crop yield loss. Ozone alsocauses noticeable foliar damage in manycrops, trees, and ornamental plants (i.e.,grass, flowers, shrubs, and trees) andcauses reduced growth in plants.Studies indicate that current ambientlevels of ozone are responsible fordamage to forests and ecosystems(including habitat for native animalspecies).

The science of ozone formation,transport, and accumulation is complex.Ozone is produced and destroyed in acyclical set of chemical reactionsinvolving NOX, VOC and sunlight.Emissions of NOX and VOC arenecessary for the formation of ozone inthe lower atmosphere. In part of thecycle of reactions, ozone concentrationsin an area can be lowered by thereaction of nitric oxide with ozone,forming nitrogen dioxide; as the airmoves downwind and the cyclecontinues, the nitrogen dioxide formsadditional ozone. The importance ofthis reaction depends, in part, on therelative concentrations of NOX, VOCand ozone, all of which change withtime and location.

As part of the efforts to reduceharmful levels of smog, EPA todayproposes to require certain States torevise their SIPs in order to implementthe regional reductions in transportedozone and its precursors that are neededto enable areas in the Eastern United

States to attain and maintain theNAAQS. Since air pollution travelsacross county and State lines, it isessential for State governments and airpollution control agencies to cooperateto solve the problem.

C. Statutory and Regulatory Background

1. Clean Air Act Provisions

a. 1970 and 1977 Clean Air ActAmendments. For almost 30 years,Congress has focused major efforts oncurbing tropospheric ozone. In 1970,Congress amended title I of the CAA torequire, among other things, that EPAissue, and periodically review and ifnecessary revise, NAAQS for ubiquitousair pollutants (sections 108 and 109).Congress required the States to submitSIPs to attain those NAAQS, andCongress included, in section 110, a listof minimum requirements that SIPsmust meet. Congress anticipated thatareas would attain the NAAQS by 1975.

In 1977, Congress amended the CAAto provide, among other things,additional time for areas to attain theozone NAAQS, as well as to imposespecific SIP requirements for thosenonattainment areas. These provisionsfirst required the designation of areas asattainment, nonattainment, orunclassified, under section 107; andthen required that SIPs for ozonenonattainment areas include theadditional provisions set out in part Dof title I, as well as demonstrations ofattainment of the ozone NAAQS byeither 1982 or 1987 (section 172).

In addition, the 1977 Amendmentsincluded two provisions focused oninterstate transport of air pollutants: thepredecessor to current section110(a)(2)(D), which requires SIPs for allareas to constrain emissions withcertain adverse downwind effects; andsection 126, which authorizes adownwind State (or politicalsubdivision) to petition for EPA toimpose limits directly on upwindsources found to adversely affect thatState. Section 110(a)(2)(D), which is keyto the present action, is described inmore detail below.

b. 1990 Clean Air Act Amendments.In 1990, Congress amended the CAA tobetter address, among other things,continued nonattainment of the 1-hourozone NAAQS, the requirements thatwould apply if EPA revised the 1-hourstandard, and transport of air pollutantsacross State boundaries (Pub. L. 101–549, Nov. 15, 1990, 104 Stat. 2399,codified at 42 U.S.C. 7401–7671q).Numerous provisions added, or revised,by the 1990 Amendments are relevant totoday’s proposal.


1 For moderate ozone nonattainment areas, theattainment demonstration was due November 15,1993 (section 182(b)(1)(A), except that if the Stateelected to conduct an urban airshed model, EPAallowed an extension to November 15, 1994.

2 In addition, section 115 authorizes EPA torequire a SIP revision when a State’s emitters‘‘cause or contribute to air pollution which mayreasonably be anticipated to endanger public healthor welfare in a foreign country.’’

i. 1-hour Ozone NAAQS. In the 1990Amendments, Congress required theStates and EPA to review and, ifnecessary, revise the designation ofareas as attainment, nonattainment, andunclassifiable under the ozone NAAQSin effect at that time, which was the 1-hour standard (section 107(d)(4)). Areasdesignated as nonattainment weredivided into, primarily, fiveclassifications based on air qualitydesign value (section 181(a)(1)). Eachclassification carries specificrequirements, including new attainmentdates (sections 181–182). In increasingseverity of the air quality problem, theseclassifications are marginal, moderate,serious, severe and extreme. The OTAGregion includes all classifications exceptextreme.

As amended in 1990, the CAArequires States containing ozonenonattainment areas classified asserious, severe, or extreme to submitseveral SIP revisions at various times.One set of SIP revisions includedspecified control measures, such asreasonably available control technology(RACT) for existing VOC and NOX

sources (section 182(b)(2), 182(f)). Inaddition, the CAA requires thereduction of VOC in the amount of 15percent by 1996 from a 1990 baseline(section 182(b)(1)). Further, the CAArequires the reduction of VOC or NOX

emissions in the amount of 9 percentover each 3-year period from 1996through the attainment date (the rate-of-progress (ROP) SIP submittals) undersection 182(c)(2)(B). In addition, theCAA requires a demonstration ofattainment (including air qualitymodeling) for the nonattainment area(the attainment demonstration), as wellas SIP measures containing anyadditional reductions that may benecessary to attain by the applicableattainment date (section 182(c)–(e)). TheCAA established November 15, 1994 asthe required date for the ROP andattainment demonstration SIPsubmittals.1

ii. Revised Ozone NAAQS. Section109(d) of the CAA requires periodicreview and, if appropriate, revision ofthe NAAQS. As amended in 1990, theCAA further requires designating areasas attainment, nonattainment, andunclassifiable under a revised NAAQS(section 107(d)(1)). The CAA authorizesEPA to classify areas that are designatednonattainment under a new NAAQS,and to establish for those areasattainment dates not to exceed 10 years

from the date of designation (section172(a)).

The CAA continues, in revised form,certain requirements, dating from the1970 Amendments, which pertain to allareas, regardless of their designation.All areas are required to submit SIPswithin certain time frames (section110(a)(1)), and those SIPs must includespecified provisions, under section110(a)(2). In addition, SIPs fornonattainment areas are generallyrequired to include additional specifiedcontrol requirements, as well as controlsproviding for attainment of the revisedNAAQS and periodic reductionsproviding ‘‘reasonable further progress’’in the interim (section 172(c)).

iii. Provisions Concerning Transportof Ozone and Its Precursors. The 1990Amendments reflect general awarenessby Congress that ozone is a regional, andnot merely a local, problem. Asdescribed above, ozone and itsprecursors may be transported longdistances across State lines to combinewith ozone and precursors downwind,thereby exacerbating the ozoneproblems downwind. In the case ofozone, this transport phenomenon wasnot generally recognized until relativelyrecently. Yet, ozone transport is a majorreason for the persistence of the ozoneproblem, notwithstanding theimposition of numerous controls, bothFederal and State, across the country.

Section 110(a)(2)(D) provides one ofthe most important tools for addressingthe problem of transport. Thisprovision, which applies by its terms toall SIPs for each pollutant covered by aNAAQS, and for all areas regardless oftheir attainment designation, providesthat a SIP must contain provisionspreventing its sources from contributingsignificantly to nonattainment problemsor interfering with maintenance indownwind States.

Section 110(k)(5) authorizes EPA tofind that a SIP is substantiallyinadequate to meet any CAArequirement, as well as to mitigateinterstate transport of the type describedin section 184 (concerning ozonetransport in the northeast) or section176A (concerning interstate transport ingeneral) and thereby require the State tosubmit, within a specified period, a SIPrevision to correct the inadequacy. TheCAA further addresses interstatetransport of pollution in section 126,which Congress clarified in 1990.Subparagraph (b) of that provisionauthorizes each State (or politicalsubdivision) to petition EPA for afinding that emissions from ‘‘any majorsource or group of stationary sources’’ inan upwind State contribute significantlyto nonattainment in, or interfere with

maintenance by, the downwind State. IfEPA makes such a finding in support ofa section 126 petition, EPA wouldimpose limits on the affected source orgroup of sources (section 126(c)).2

In addition, the 1990 Amendmentsincluded specific provisions focused onthe interstate transport of ozone. Section184 delineates a multistate ozonetransport region (OTR) in the Northeast,requires specific additional controls forall areas (not only nonattainment areas)in that region, and establishes the OzoneTransport Commission (OTC) for thepurpose of recommending to EPAregionwide controls affecting all areas inthat region.

2. Regulatory Structurea. March 2, 1995 Policy.

Notwithstanding significant efforts, theStates generally were not able to meetthe November 15, 1994 statutorydeadline for the attainmentdemonstration and other SIPsubmissions required under section182(c). The major reason for this failurewas that States were not able to addressor control transport. As a result, in amemorandum from Mary D. Nichols,Assistant Administrator for Air andRadiation, dated March 2, 1995, entitled‘‘Ozone Attainment Demonstrations,’’(March 2, 1995 Memorandum or theMemorandum), EPA recognized theefforts made by States and theremaining difficulties in making theROP and attainment demonstrationsubmittals. The EPA recognized thatdevelopment of the necessary technicalinformation, as well as the controlmeasures necessary to achieve the largelevel of reductions likely to be required,had been particularly difficult for theStates affected by ozone transport.

Accordingly, as an administrativeremedial matter, the Memorandumindicated that EPA would establish newtime frames for SIP submittals. TheMemorandum indicated that EPA woulddivide the required SIP submittals intotwo phases. Phase I generally consistedof: SIP measures providing for ROPreductions due by the end of 1999, anenforceable SIP commitment to submitany remaining required ROP reductionson a specified schedule after 1996, andan enforceable SIP commitment tosubmit the additional SIP measuresneeded for attainment. Phase II consistsof the remaining submittals, beginningin 1997.

Ten States and the District ofColumbia failed to submit Phase I


elements within the specified time. Bynotice dated July 10, 1996 (61 FR36292), EPA issued findings and therebystarted sanctions clocks for these areasfor those Phase I submittals.

The Phase II submittals primarilyconsisted of the remaining ROP SIPmeasures, the attainment demonstrationand additional local rules needed toattain, and any regional controls neededfor attainment by all areas in the region.The March 2, 1995 Memorandumindicated that the attainmentdemonstration, target calculations forthe post-1999 ROP milestones, andidentification of rules needed to attainand for post-1999 ROP were due in mid-1997. To allow time for States toincorporate the results of the OTAGmodeling into their local plans, EPA, inits Final Policy for Implementation ofthe 1-hour and Pre-Existing PM–10Standards, is extending the mid-1997submittal date to April 1998.

b. OTAG. In addition, the March 21995 Memorandum called for anassessment of the ozone transportphenomenon. The EnvironmentalCouncil of States (ECOS) hadrecommended formation of a nationalwork group to allow for a thoughtfulassessment and development ofconsensus solutions to the problem. TheOTAG has been a partnership betweenEPA, the 37 easternmost States and theDistrict of Columbia, industryrepresentatives and environmentalgroups. This effort has created anopportunity for the development of anEastern United States ozone strategy toaddress transport and to assist inattainment of the 1-hour ambient ozonestandard.

The EPA believes that the OTAGprocess has been invaluable indemonstrating the types of regionalozone precursor reductions that areneeded to enable areas in the EasternUnited States to attain and maintain theambient air quality standard for ozone.Indeed, today’s action to propose tomandate SIP revisions under section110(a)(2)(D) is a first step directed atproviding the regulatory structure toimplement the kinds of broad regionalprecursor reductions recommended byOTAG.

c. EPA’s Transport SIP CallRegulatory Efforts. Shortly after OTAGbegan its work, EPA began to indicatethat it intended to issue a SIP call torequire States to implement thereductions necessary to address theozone transport problem. On January 10,1997 (62 FR 1420), EPA published aNotice of Intent that articulated this goaland indicated that before taking finalaction, EPA would carefully consider

the technical work and anyrecommendations of OTAG.

By a letter to Mary Gade, Chair ofOTAG, dated April 16, 1997, EPAAssistant Administrator Mary D.Nichols stated that on the basis oftechnical work performed by EPA staff,it appeared that EPA would issue a SIPcall to specified States and the Districtof Columbia. The EPA staff issued atechnical support document,‘‘Preliminary Assessment of StatesMaking a Significant Contribution toDownwind Ozone Nonattainment,’’dated April, 1997, which explainedEPA’s technical basis for those tentativeconclusions. Please refer to section II,Weight of Evidence Determination ofSignificant Contribution, for EPA’srevised conclusions.

As described below in section I.F.,OTAG Process, OTAG completed itswork in June 1997 and issued its finalrecommendations to EPA on July 8,1997. The OTAG’s technical work andrecommendations form part of the basisof today’s proposal.

d. Revision of the Ozone NAAQS. OnJuly 18, 1997 (62 FR 38856), EPA issuedits final action to revise the NAAQS forozone. The EPA’s decision to revise thestandard was based on the Agency’sreview of the available scientificevidence linking exposures to ambientozone to adverse health and welfareeffects at levels allowed by the pre-existing 1-hour ozone standards. The 1-hour primary standard was replaced byan 8-hour standard at a level of 0.08parts per million (ppm), with a formbased on the 3-year average of theannual fourth-highest daily maximum 8-hour average ozone concentrationmeasured at each monitor within anarea. The new primary standard willprovide increased protection to thepublic, especially children and other at-risk populations, against a wide range ofozone-induced health effects. Healtheffects are described in section I.B,General Factual Background. The EPAretained the applicability of the 1-hourNAAQS for certain areas to ensureadequate health protection during thetransition to full implementation of the8-hour NAAQS.

The pre-existing 1-hour secondaryozone standard was replaced by an 8-hour standard identical to the newprimary standard. The new secondarystandard will provide increasedprotection to the public welfare againstozone-induced effects on vegetation asdescribed in section I.B, General FactualBackground.

e. Impacts of NOX Emissions. At theAugust 7, 1997 Clean Air Act AdvisoryCommittee meeting, EPA announced theavailability of a document (‘‘Nitrogen

Oxides: Impacts on Public Health andthe Environment,’’ EPA–452/R–97–002,August 1997) that describes the multipleimpacts of NOX emissions on publichealth and the environment and theconsequent implications for nationalpolicy. In addition to helping attainpublic health standards for ozone,decreases in emissions of NOX arehelpful to reducing acid deposition,greenhouse gases, nitrates in drinkingwater, stratospheric ozone depletion,excessive nitrogen loadings to aquaticand terrestrial ecosystems, and ambientconcentrations of nitrogen dioxide,particulate matter and toxics. Theseimpacts are described in more detail insection X, Nonozone Benefits of NOX

Reductions.

D. EPA’s Proposed Analytical Approach1. Process for Requiring Submission

of Section 110(a)(2)(D) SIP RevisionsAs described above, SIPs for all areas

must meet the requirements of section110(a)(2), including section 110(a)(2)(D),which imposes limits on sources thataffect the ability of downwind areas toattain and maintain the NAAQS.Because many areas are currentlyrequired to attain two ozone NAAQS—the 1-hour standard and the 8-hourstandard—with different SIP planningrequirements, EPA proposes that section110(a)(2)(D) be applied in different wayswith respect to each of the ozoneNAAQS.

Under the 1-hour ozone NAAQS, eacharea is currently required to have a SIPin place. Moreover, EPA has determinedthat the 1-hour standard will continueto apply to areas designatednonattainment for the 1-hour NAAQSuntil EPA determines that the area hasair quality meeting this standard (40CFR 50.9(a) (62 FR 38894 (July 18,1997)). Accordingly, each area is undera current obligation to include in its SIP,provisions that meet the requirements ofsection 110(a)(2)(D) for the 1-hourNAAQS.

This obligation to meet section110(a)(2)(D) under the 1-hour standardapplies even after EPA determines thatan upwind area has attained the 1-hourstandard, and the applicability of thatstandard thereby terminates for theupwind area. Regardless of the status ofthe 1-hour standard with respect to theupwind area’s air quality, a downwindarea may continue to have anonattainment problem under the 1-hour standard, and the upwind area’ssources may continue to impact thatdownwind nonattainment problem.Under these circumstances, the upwindarea would be required to retain oradopt SIP provisions that meet therequirements of section 110(a)(2)(D).


To assure that SIPs include requiredcontrols, section 110(k)(5) authorizesEPA to find that a SIP is substantiallyinadequate to meet an CAArequirement, and to require (‘‘call for’’)the State to submit, within a specifiedperiod, a SIP revision to correct theinadequacy. This EPA requirement for aSIP revision is known as a ‘‘SIP call.’’Specifically, section 110(k)(5) provides,in relevant part:

Whenever the Administrator finds that theapplicable implementation plan for any areais substantially inadequate to attain ormaintain the relevant [NAAQS], to mitigateadequately the interstate pollutant transportdescribed in section 176A or section 184, orto otherwise comply with any requirement ofthis Act, the Administrator shall require theState to revise the plan as necessary tocorrect such inadequacies. The Administratorshall notify the State of the inadequacies, andmay establish reasonable deadlines (not toexceed 18 months after the date of suchnotice) for the submission of such planrevisions.

By today’s action, EPA is proposing todetermine that the SIPs under the 1-hour ozone NAAQS for the Statesidentified in today’s action aresubstantially inadequate to comply withthe requirements of section 110(a)(2)(D)and to mitigate adequately the regional,interstate ozone transport described insection 184, because ozone precursoremissions and transported ozone fromthose States contribute significantly tononattainment downwind. Based onthese findings, EPA today proposes aSIP call to require the identified Statesto reduce emissions to mitigate theircontribution.

If a State fails to submit the requiredSIP provisions in response to this SIPcall, EPA is required to issue a findingthat the State failed to make a requiredSIP submittal under section 179(a). Thisfinding has implications for sanctions aswell as EPA’s promulgation of a Federalimplementation plan (FIP). Sanctionsand a FIP are discussed in section V.,SIP Revisions and ApprovabilityCriteria.

Under the 8-hour ozone NAAQS,areas have not yet been designated asattainment, nonattainment, orunclassifiable, and are not yet requiredto have SIPs in place. When those SIPsbecome due, they must meet theapplicable requirements of section 110,which apply to all areas, and SIPs forareas designated nonattainment mustalso meet the additional requirements insubpart 1 of part D applicable tononattainment areas.

Section 110(a)(1) provides, in relevantpart—

Each State shall * * * adopt andsubmit to the Administrator, within 3

years (or such shorter period as theAdministrator may prescribe) after thepromulgation of a national primaryambient air quality standard (or anyrevision thereof) * * * a plan whichprovides for implementation,maintenance, and enforcement of suchprimary standard in each (area) withinsuch State.

Section 110(a)(2) provides, in relevantpart—

Each implementation plan submitted by aState under this CAA shall be adopted by theState after reasonable notice and publichearing. Each such plan shall (meet certainrequirements, including those found insection 110(a)(2)(D)).

These two provisions, read together,require SIP revisions under the revisedNAAQS within 3 years of the date of therevision, or earlier if EPA so requires,and require that those SIP revisionsmeet the requirements of section110(a)(2), including subparagraph (D). Itshould be noted that the schedule forthese section 110(a)(2) SIP submissionsfor all ozone areas differs from theschedule for the SIP submissionsrequired under section 172(b) for part DSIP submissions for ozonenonattainment areas. These part D SIPsubmissions are required for all areasthat are designated nonattainment underthe 8-hour NAAQS and must besubmitted within 3 years of the date ofdesignation. The submission of SIPrevisions containing the regional NOX

reductions proposed under thisrulemaking earlier than the part Dnonattainment submissions will assistthe downwind nonattainment areas intheir attainment planning.

The EPA believes it has the authorityto establish different submittalschedules for different parts of thesection 110(a)(1) SIP revision.Specifically, EPA proposes to requirefirst the portion of the section 110(a)(1)SIP revision that contains the controlsrequired under section 110(a)(2)(D). TheEPA proposes to require the section110(a)(2)(D) submittal first for thepurpose of securing upwind reductionsat an earlier stage in the regional SIPplanning process. This information oncontrols in upwind States is essential tothe downwind States in the latter States’attainment planning.

In summary, EPA is proposing todetermine, under section 110(k), thatthe 1-hour ozone NAAQS SIPs forcertain States are deficient because theSIPs do not impose sufficient controlson their sources to meet therequirements of section 110(a)(2)(D),and EPA is proposing to require thoseStates to submit SIP revisionscontaining adequate controls. The EPA

is proposing to require, under section110(a)(1), that certain States mustsubmit SIP revisions under the 8-hourozone NAAQS to meet the requirementsof section 110(a)(2)(D). For simplicity,today’s rulemaking occasionally usesthe term ‘‘SIP call’’ to describe both EPAactions.

2. Overview of Elements of Section110(a)(2)(D)

a. Summary of Section 110(a)(2)(D).As noted above, section 110(a)(2)(D) isthe operative provision for determiningwhether additional controls are requiredto mitigate the impact of upwindsources on downwind air quality, withrespect to both the 1-hour and 8-hourozone NAAQS. Separate determinationsmust be made for each NAAQS.

Section 110(a)(2)(D) provides, inrelevant part, that each SIP must:* * * contain adequate provisions * * *prohibiting, consistent with the provisions ofthis title, any source or other type ofemissions activity within the State fromemitting any air pollutant in amounts whichwill * * * contribute significantly tononattainment in, or interfere withmaintenance by, any other State with respectto any such national primary or secondaryambient air quality standard * * *.

According to section 110(a)(2)(D), theSIP for each area, regardless of itsdesignation as nonattainment orattainment (including unclassifiable),must prohibit sources within the areafrom emitting emissions that:‘‘contribute significantly’’ to‘‘nonattainment’’ in a downwind State,or that ‘‘interfere with maintenance’’ ina downwind State.

b. Significant Contribution toNonattainment. The initial prong undersection 110(a)(2)(D) is whether sources‘‘contribute significantly’’ to‘‘nonattainment in * * * any otherState’’ with respect to the NAAQS. Theinitial inquiry for this prong is toidentify and determine the geographicscope of ‘‘nonattainment’’ downwind.The EPA proposes to interpret this termto refer to air quality and not to belimited to currently-designatednonattainment areas. Section110(a)(2)(D) does not refer to‘‘nonattainment areas,’’ which is aphrase that EPA interprets to refer toareas that are designated nonattainmentunder section 107 (section107(d)(1)(A)(I)). Rather, the provisionincludes only the term ‘‘nonattainment’’and does not define that term. Underthese circumstances, EPA has discretionto give the term a reasonable definition,and EPA proposes to define it to includeareas whose air quality currentlyviolates the NAAQS, and will likelycontinue for some time to violate,


regardless of the designation of thoseareas (compare section 181(b)(2)(A)(referring to ozone ‘‘nonattainmentarea’’ which EPA interprets as an areadesignated nonattainment) and section211(k)(10)(D)).

For present purposes, EPA isexamining the air quality for the 1993–1995 years, but EPA expects to refer to1996 (and perhaps 1997) data as therulemaking proceeds.

As discussed below, to determinewhether emissions from sources in anupwind area significantly contribute tononattainment downwind, EPAproposes to compare NOX emissionsreductions upwind with ozonereductions downwind. For this purpose,EPA assumes that areas with current airquality indicating nonattainment for the1-hour standard will be required toimplement certain controls under theCAA, through the year 2007, which isthe attainment date for ozonenonattainment areas classified as severe-17. Accordingly, EPA proposes todetermine, through air qualitymodeling, which areas with current airquality indicating nonattainment forboth the 1-hour and 8-hour standardswill continue to be in nonattainment inthe year 2007, even afterimplementation of controls specificallyrequired under the CAA. Because thisprojection is occurring through the year2007, it is also necessary to take intoaccount growth in emissions, generallydue to economic growth and greater useof vehicles, to that time. If an area withair quality currently indicatingnonattainment is modeled to continueto be in nonattainment as of the year2007, then emissions from sources inupwind areas may be considered to‘‘contribute significantly’’ to the currentnonattainment problem, depending onthe factors described below. On theother hand, if an area the current airquality of which measuresnonattainment is modeled to be inattainment in the year 2007 due toimposition of required CAA controls,then EPA proposes not to consideremissions from sources in upwind areasto ‘‘contribute significantly’’ to thatdownwind area.

The EPA’s decision is explainedbelow for choosing the year 2007 as thedate for assuming the implementation ofcontrols and for modeling air quality.

The EPA proposes a similar analysisfor purposes of the 8-hour NAAQS. TheEPA will consider as ‘‘nonattainment’’any area that has monitorednonattainment air quality currently, andfor which modeling shows is likely tocontinue to be in nonattainment in theyear 2007 after application of controlsspecifically required under the CAA.

After determining the scope of thedownwind nonattainment problem, EPAmust next analyze whether theemissions from sources in the upwindarea ‘‘contribute significantly’’ to thenonattainment problem. As describedbelow, EPA analyzed all NOX emissionsin specified upwind areas, madeproposed determinations as tosignificant contributions based on theentire inventory of the area’s NOX

emissions and is requiring SIP revisionsthat address overall levels of NOX

emissions. By contrast, EPA is not, inthis rulemaking, determining whetherparticular sectors of the NOX inventory‘‘contribute significantly’’ and is notmandating controls on particular sectorsof that inventory.

Neither the CAA nor its legislativehistory provides meaningful guidancefor interpreting the term, ‘‘contributesignificantly’’ (H.Rept. 101–491, 101stCong., 2d sess., 1990, 218). The simplerpart of the analysis concerns the term,‘‘contribute.’’ In EPA’s view, ifemissions have an impact on downwindnonattainment, those emissions shouldbe considered to contribute to thenonattainment problem. Generally,because ozone is a secondary pollutantformed as a result of complex chemicalreactions, it is not possible to determinedownwind impact on a source-by-source basis. However, if air qualitymodeling shows that the aggregation ofemissions from a particular geographicregion affect a nonattainment problem,then all of the emissions in that regionshould be considered as contributors tothat nonattainment problem.

Whether a contribution from sourcesin a particular upwind area is‘‘significant’’ depends on the overall airquality context. The EPA is proposing a‘‘weight of evidence’’ test under whichseveral factors are considered together,but none of them individuallyconstitutes a bright-line determination.

The EPA is proposing and solicitingcomment on two alternativeinterpretations of section 110(a)(2)(D).Each of the two interpretations relies ona set of factors to make thedeterminations required under section110(a)(2)(D). In addition, each of the tworelies on the same factors. However,each relies on different factors indifferent parts of the analysis.

Under the first interpretation ofsection 110(a)(2)(D), the weight ofevidence test for determining significantcontribution focuses on factorsconcerning amounts of emissions andtheir ambient impact, including thenature of how the pollutant is formed,the level of emissions and emissionsdensity (defined as amount of emissionsper square mile) in the particular

upwind area, the level of emissions inother upwind areas, the amount ofcontribution to ozone in the downwindarea from upwind areas, and thedistance between the upwind sourcesand the downwind nonattainmentproblem. Under this approach, whenemissions and ambient impact reach acertain level, as assessed by reference tothe factors identified above, thoseemissions would be considered to‘‘contribute significantly’’ tononattainment. The EPA would thendetermine what emissions reductionsmust be required in order to adequatelymitigate these contributions. Evaluationof the costs of available measures forreducing upwind emissions enters intothis determination, as well as to theextent known (at least qualitatively), therelative costs of, amounts of emissionreductions from, and ambient impact of,measures available in the downwindareas. The EPA proposes to requireupwind areas to implement a NOX

budget reflecting cost-effective controlsthat compare favorably, at leastqualitatively, with the costs of controlsdownwind and that reduces ozonelevels downwind.

Under the second interpretation ofsection 110(a)(2)(D), the weight ofevidence test for determining significantcontribution includes all of the factorsidentified immediately above, includingthe factors that comprise the adequatemitigation test. That is, the relevantfactors concern upwind emissions andambient impact therefrom, as well as thecosts of the available measures forreducing upwind emissions and, to theextent known (at least qualitatively), therelative costs of, amounts of emissionsreductions from, and ambient impact ofmeasures available in the downwindareas. Thus, under this secondinterpretation, the cost effectiveness ofcontrolling upwind emissions would bean important, but not necessarily acontrolling factor in evaluating whetheremissions meet the significantcontribution test. As a result, EPA mayconclude that a certain amount of theupwind emissions contributessignificantly to downwind problemsbecause, among other things, thatamount may be eliminated throughcontrols that are relatively more costeffective. However, EPA would notconclude that the remaining emissionscontribute significantly because theadditional available controls that mightbe implemented are not as cost effective.Under this second interpretation, onceEPA determines what amount ofemissions contribute significantly toproblems downwind, the remedy wouldbe for EPA to require the elimination of


that amount of upwind emissions and todetermine the NOX budgets accordingly.

Under either the first or secondinterpretation of section 110(a)(2)(D),EPA would be considering the relativecosts and cost effectiveness of variouscontrols in deciding how much eachState would need to reduce itsemissions. The methodology EPA wouldemploy to reach this result under eitherinterpretation is set forth more fully insections II and III of today’s action.

As discussed above, unhealthfullevels of ozone result from emissions ofNOX and VOC from thousands ofstationary sources and millions ofmobile sources across a broadgeographic area. Each source’scontribution is a small percentage of theoverall problem; indeed, it is rare foremissions from even the largest singlesources to exceed 1 percent of theinventory of ozone precursors for asingle metropolitan area. Under thesecircumstances, even completeelimination of any given source’semissions may well have no measurableimpact in ameliorating thenonattainment problem. Rather,attainment requires controls onnumerous sources across a broad area.Ozone is a regional scale problem thatrequires regional scale reductions.

The National Academy of Sciences(NAS) study, ‘‘Rethinking the OzoneProblem in Urban and Regional AirPollution’’ (2) emphasized this aspect ofozone formation. According to thisreport, high concentrations of ozoneoccur concurrently in the EasternUnited States in urban, suburban andrural areas on scales of over 1000kilometers. The NAS report describes a‘‘persistent blanket of high ozone in theEastern United States’’ that can last forseveral days. Since rural ozone valuescommonly exceed 90 parts per billion(ppb) on these occasions, an urban areaneeds an ozone increment of only 30ppb to cause an exceedance of the 1-hour ozone standard in a downwindarea. Clearly, attainment strategies mustinclude controls on numerous sourcesacross broad areas.

In light of this ‘‘collectivecontribution’’ characteristic of ozoneformation and control, EPA proposesthat if contributions from an upwindarea’s emissions, taken together, areconsidered to be an important portion ofthe downwind area’s nonattainmentproblem, then this factor tends toindicate that the upwind emissions as awhole, as well as each of the upwindemitters, make a ‘‘significant’’contribution. The fact that emissionsfrom any particular source, or even agroup of sources, may in-and-of-themselves be small, does not mean

those sources’ emissions are not‘‘significant’’ within the meaning ofsection 110(a)(2)(D). Those sources’emissions are generally ‘‘significant’’ if,when they are combined with emissionsfrom other sources in the same upwindarea, they total upwind emissions thatare ‘‘significant.’’ Even so, it should benoted that the collective contributionfactor is only one of various factors thatEPA proposes to consider indetermining whether emissions from anarea constitute a ‘‘significant’’contribution to a downwind problem.The amounts of emissions from the areaand, in certain cases, emissions density,remain important factors. Depending onall the facts and circumstances, theseother factors may tend to indicate thatemissions from a particular area shouldnot be considered to contributesignificantly, notwithstanding the factthat those emissions may be linked insome manner with emissions from otherupwind areas that are considered to besignificant contributors.

In several rulemakings promulgatedand court decisions handed down, inthe 1980’s, EPA interpreted and appliedthe predecessors to sections 110(a)(2)(D)and 126 (e.g., State of New York v. EPA,852 F.2d 574 (D.C. Cir. 1988); AirPollution Control District of JeffersonCounty, Kentucky v. EPA, 739 F.2d 1071(6th Cir. 1984); Connecticut v. EPA, 696F.2d 147 (2d Cir. 1982)). Although theserulemakings and court decisionsgenerally employed multifactorformulas for the ‘‘significantcontribution’’ test that bear somesimilarity to the formula EPA isproposing today, they have limitedrelevance to the issues in the presentrulemaking because of the numerousdifferences in the relevant factors. Forexample, in the earlier rulemakingscompared to the present rulemaking, thepollutants and precursors are different,and the inventories of emissions andnumber of emitters in the upwind anddownwind areas are different. Thesignificant contribution test is a facts-and-circumstances analysis thatdepends on these factors, anddifferences among these factors mayyield different results under this test.Accordingly, the differences in the keyfactors between the earlier decisionsand today’s proposal means that thoseearlier decisions are not determinativefor today’s proposed action.

For purposes of today’s rulemaking,EPA determined the amount ofcontribution to downwind air quality,under both the 1-hour NAAQS and the8-hour NAAQS, by employing an airquality model that assumed a zero levelof anthropogenic emissions from thevarious upwind areas. The results of

those model runs, as well as their otherassumptions and characteristics, aredescribed in detail below.

As described below, EPA madeseparate determinations as to whichupwind areas ‘‘contribute significantly’’to nonattainment under the 1-hourNAAQS and under the 8-hour NAAQS.Those separate determinations resultedin identifying the same States for boththe 1-hour and the 8-hour NAAQS.

c. Interfere with Maintenance. Section110(a)(2)(D) also prohibits emissionsthat ‘‘interfere with maintenance’’ of theNAAQS in a downwind State. An areais obligated to maintain the NAAQSafter the area has reached attainment.This requirement of section 110(a)(2)(D)does not, by its terms, incorporate thequalifier of ‘‘significantly.’’ Even so,EPA believes that for present purposes,the term ‘‘interfere’’ should beinterpreted much the same as the term‘‘contribute significantly,’’ that is,through the same weight of evidenceapproach.

With respect to the 1-hour NAAQS,the ‘‘interfere-with-maintenance’’ prongappears to be inapplicable. The EPA hasdetermined that the 1-hour NAAQS willno longer apply to an area after EPA hasdetermined that the area has attainedthat NAAQS. Under thesecircumstances, emissions from anupwind area cannot interfere withmaintenance of the 1-hour NAAQS.

With respect to the 8-hour NAAQS,the ‘‘interfere-with-maintenance’’ prongremains important. After an area hasreached attainment of the 8-hourNAAQS, that area is obligated tomaintain that NAAQS (sections110(a)(1) and 175A). Emissions fromsources in an upwind area may interferewith that maintenance.

The EPA proposes to apply much thesame approach in analyzing the firstcomponent of the ‘‘interfere-with-maintenance’’ issue, which isidentifying the downwind areas whosemaintenance of the NAAQS may sufferinterference due to upwind emissions.The EPA has analyzed the ‘‘interfere-with-maintenance’’ issue for the 8-hourNAAQS by examining areas whosecurrent air quality is monitored asattaining the 8-hour NAAQS, but forwhich air quality modeling showsnonattainment in the year 2007. Thisresult is projected to occur,notwithstanding the imposition ofcertain controls required under theCAA, because of projected increases inemissions due to growth in emissionsgenerating activity. Under thesecircumstances, emissions from upwindareas may interfere with the downwindarea’s ability to maintain the 8-hourNAAQS. Ascertaining the impact on the


downwind area’s air quality of theupwind area’s emissions aids indetermining whether the upwindemissions interfere with maintenance.

d. Remedying the SignificantContribution. After identifying Stateswhose sources do ‘‘contributesignificantly’’ to a nonattainmentproblem or interfere with maintenancedownwind, it is necessary to determinethe appropriate limit on emissionsrequired in each upwind SIP. The EPAis proposing, in the alternative, twodifferent analyses for the remedieswhich are tied to the two alternatives forthe ‘‘weight of evidence’’ test.

i. Adequate Mitigation. Under the firstinterpretation of section 110(a)(2)(D),EPA does not consider costs indetermining whether upwind emissionscontribute significantly tononattainment or interfere withmaintenance. Instead, once EPAdetermines, on the basis of factorsgenerally related to emissions, thatthose emissions do contributesignificantly to nonattainment (orinterfere with maintenance), EPA thendetermines what emissions reductionsmust be required in order to adequatelymitigate these contributions. Evaluationof relative costs enters into thisdetermination.

Adequate mitigation would amount toeliminating a sufficient portion of theupwind emissions so that they no longercontribute significantly tononattainment or interfere withmaintenance.

In the present case, EPA proposes todetermine an allowable level of NOX

emissions for each of the 23jurisdictions with sources that triggerthe requirements of section 110(a)(2)(D).Given the need to reduce this overallregional level of ozone, as discussedearlier, EPA determined this ‘‘budget’’of emissions by, in the first instance,calculating the emissions achievable byapplying the most reasonable, cost-effective controls on NOX emissions inthe 23 jurisdictions. The controlmeasures considered and thosedetermined to be the most reasonableand cost-effective are detailed below. Inselecting those control measuresdetermined to be the most reasonableand cost-effective, EPA carefullyconsidered the recommendations madeby OTAG on July 8, 1997. (The OTAGprocess is described in section I.F. ofthis rulemaking.) The budgetcalculations described below generallyfall within the range of OTAG’srecommendations.

The statewide emissions budgetsproposed in this rulemaking were notmodeled directly to determine their airquality benefits. The EPA believes,

however, that the air quality impact ofimplementing these reductions wouldbe very similar to results previouslymodeled by OTAG. This modeling isidentified in section IX, Air QualityAnalyses. The downwind air qualitybenefits from these reductions aresufficient for EPA to conclude that theywould adequately mitigate thecontribution from the upwind sources.

ii. Elimination of Contribution. Underthe second interpretation of section110(a)(2)(D), costs are considered as partof the calculation as to what (if any)amount of emissions contributesignificantly to nonattainment orinterfere with maintenance. The EPAproposes to determine those amountsfor each State by considering the factorsdescribed above and the extent to whichthe State’s emissions can be reducedthrough the most cost-effective controlsthat reduce ozone levels downwind.Once EPA makes this determination,EPA would conclude that requiringthose cost-effective controls is mandatedunder the provisions of section110(a)(2)(D) that require SIP provisions‘‘prohibiting’’ that amount of emissions.Thus, under this alternativeinterpretation, a SIP meets therequirement for ‘‘prohibiting’’ emissionsthat contribute significantly tononattainment, or interfere withmaintenance, downwind, byimplementing cost-effective controlsdetermined to improve air qualitydownwind.

iii. Comparison of the Two LegalInterpretations of Section 110(a)(2)(D).The EPA solicits comments on which ofthe two legal interpretations of section110(a)(2)(D), as described above, shouldbe used. Each interpretation relies onthe same factors (although certainfactors enter into different parts of theanalysis under the two interpretations).Because each relies on the same factors,there is little technical differencebetween the two interpretations. Eachrequires the same determinations as to,for example, the ambient impact ofupwind emissions and the costeffectiveness of controls.

Moreover, as proposed in today’saction, each interpretation leads to thesame conclusion as to which States areconsidered to have emissions thatsignificantly contribute to downwindproblems, and as to the amounts of NOX

budgets that those States should meet.However, the two interpretations have

different legal justifications. As notedabove, section 110(a)(2)(D) provides thatthe SIP for the upwind area must‘‘contain adequate provisions * * *prohibiting * * * [sources] fromemitting any air pollutant in amountswhich will * * * contribute

significantly to nonattainment in, orinterfere with maintenance by, anyother State * * *’’ Under the firstinterpretation, EPA may determine thata relatively larger inventory ofemissions contributes significantly tononattainment (or interferes withmaintenance) in light of the fact that thecosts of controlling those emissions arenot considered in determiningsignificant contribution. The EPA wouldthen require adequate mitigation of thefull set of emissions that contribute tononattainment or interfere withmaintenance.

Other relevant provisions indicatethat the CAA could be construed torequire mitigation, and not necessarilycomplete elimination, of emissions thatcontribute to air quality problemsdownwind. Section 110(k)(5) authorizesthe Administrator to promulgate a SIPcall whenever she finds that a SIP is‘‘substantially inadequate to attain ormaintain the relevant [NAAQS], tomitigate adequately the interstatepollutant transport described in section176A or 184, or to otherwise complywith any requirement of this Act’’(emphasis added). Section 176Adescribes interstate transport of airpollutants generally, and section 184describes ozone transport in thenortheast region in particular, whichconstitutes part of the transportphenomenon at issue in today’sproposal. Section 176A authorizes thecreation of a transport region whenemissions from one or more Statescontribute significantly to a NAAQSviolation in another State and furtherauthorizes a transport commission to,among other things, assess strategies formitigating the interstate pollution.These provisions, read together, indicatethat adequate mitigation of transport isan appropriate response to a SIP call.Arguably, this interpretation shouldhold when EPA issues a SIP call basedon section 110(a)(2)(D), and when EPAmandates a SIP revision under section110(a)(1), based on section 110(a)(2)(D).

The second interpretation focuses onthe provisions of section 110(a)(2)(D)that the SIP must include provisions to‘‘prohibit’’ any emitting activity fromemitting in ‘‘amounts’’ that contributesignificantly to downwindnonattainment or interfere withmaintenance. The EPA has determinedthe States whose full set of NOX

emissions contribute markedly todownwind problems. The term‘‘prohibit’’ could be interpreted torequire EPA, upon finding that a State’sfull set of emissions ‘‘contributesignificantly’’ to nonattainment, mustthen require the SIP to eliminate thatfull set of emissions. This construction


could mean that EPA must require theState to shut down all of the emission-generating activities. It is doubtfulCongress would have intended thisresult.

The EPA’s second interpretationavoids this possible result by taking intoaccount the relative cost effectiveness ofthe upwind and downwind controls indefining the ‘‘amounts’’ of emissions ineach State that contribute significantlyto the downwind problem. Once EPAhas set those ‘‘amounts’’ in light of itsconsideration of the cost factors, theSIPs for the affected States would thenneed to prohibit only those amounts.

iv. Other Issues. States will have theflexibility to choose their own mix ofcontrol measures to meet the proposedstatewide emissions budgets. That is,States are not constrained to adoptmeasures that mirror the measures EPAused in calculating the budgets. In fact,EPA believes that many controlmeasures not on the list relied upon todevelop EPA’s proposed budgets arereasonable—especially those likeenhanced vehicle inspection andmaintenance programs that yield bothNOX and VOC emissions reductions.Thus, one State may choose to primarilyachieve emissions reductions fromstationary sources while another Statemay focus emission reductions from themobile source sector. Furthermore,States may choose to pursue cost-effective energy efficiency opportunitiesas a means to reduce the controlmeasures necessary to meet theirstatewide emission budgets.

e. Control Implementation and BudgetAttainment Dates. The EPA proposes torequire that the SIP revisions impose animplementation date for the requiredcontrols of 3 years from the date of therequired SIP submission, which wouldresult in compliance by those sources byno later than September 2002. However,the EPA is soliciting comments on therange of implementation dates frombetween September 2002 and September2004. The EPA seeks comment onwhich date within this 2-year range isappropriate, in light of the feasibility ofimplementing controls and the need toprovide air quality benefits asexpeditiously as practicable. The EPA isproposing an implementation date ofSeptember 2002 in order to allowcoordination of this rulemaking with itsresponse to 8 section 126 petitionswhich are discussed below in sectionI.E, Section 126 Petitions. Although theEPA’s actual proposed compliance dateis September 2002, because the Agencyis seeking comment on a range fromSeptember 2002 to September 2004, theAgency refers to the range ofimplementation dates throughout this

rulemaking. The EPA further proposesthat States be required to meet themandated budgets by the end of the year2007, by which time additionalreductions from various Federalmeasures will also be achieved.

The EPA believes that requiringimplementation of the upwind controls,and thereby mandating upwindreductions, by no later than these 2002–4 dates, is consistent with theattainment schedule for the downwindareas. Because the downwind areasdepend on upwind reductions to reachattainment, mandating upwind controlson a schedule consistent withdownwind attainment requirements isappropriate.

A review of the attainment scheduleunder the 1-hour NAAQS would beuseful. Under the attainment schedule,serious areas are required to attain bythe end of 1999, severe-15 areas arerequired to attain by the end of 2005,and severe-17 areas are required toattain by the end of 2007 (section181(a)(1)). If a serious area fails to meetits 1999 attainment date, it is to bereclassified (‘‘bumped up’’) to severe-15(section 181(b)(2)). However, an areamay fail to reach attainment by itsattainment date, but avoid bump up, ifEPA grants a 1-year extension. An areais eligible for a 1-year extension if,among other things, it has no more thanone exceedance of the NAAQS in theattainment-date year. The EPA maygrant another extension for the next yearunder the same conditions (section181(a)(5)). If an area receives two 1-yearextensions, it may reach attainment inthe following year (the second year afterthe attainment-date year) if, again, it hasno more than one exceedance of theNAAQS. Under these circumstances, thearea will have had no more than threeexceedances over a 3-year period (theattainment-date year and the 2 nextyears), which would qualify it forattainment under the 1-hour NAAQS.The EPA has indicated that once itdetermines that an area has achieved airquality that satisfies the 1-hour NAAQS,the NAAQS will be rescinded withrespect to that area.

Although controls on upwindemissions are designed to assistdownwind nonattainment areas inreaching the NAAQS, EPA is aware thatat this point, it is not possible for EPAto mandate controls on upwind areaswithin the OTAG region in sufficienttime to help serious areas reachattainment by their end-of-1999attainment date. The amount of timethat is necessary to assure that therulemaking proposed today is wellconsidered by all affected parties, addedto the amount of time necessary for the

States to adopt the required SIPrevisions, and the amount of lead-timenecessary to implement the requiredcontrols, means that those controlscannot be expected to be in place intime to assist the serious areas inreaching their attainment date.

The next attainment date is 2005,which applies to severe-15 areas, suchas the Baltimore area, and which wouldapply to any serious area that is bumpedup. The EPA’s proposal to requireupwind controls to be implemented byno later than September 2004—in timefor the beginning of the ozone season forthe affected States—is sensible in lightof this 2005 attainment date.Implementing controls earlier thanSeptember 2004, or at least phasing insome controls, if not all of them, priorto that date, would improve the chancefor minimizing exceedances during the3-year period up to, and including,2005, which will facilitate reachingattainment as of this date. In particular,to the extent that the State choosescontrols on major stationary sources ofNOx, EPA believes it would be feasibleto implement some of those controlsearlier than September 2004. However,EPA is aware that implementation ofcontrols for other sources may be moreproblematic. The EPA solicits commentson what dates within the range of 3 to5 years of the required SIP submissionwould be appropriate forimplementation of the controls.

Full implementation by no later thanSeptember 2004 would mean that all ofthe upwind controls required under therulemaking proposed today would be inplace as of the November 15, 2005attainment date for the downwindsevere-15 areas. Failure to implementthose controls prior to September 2004may mean that the downwind area mayrecord too many exceedances in the 3-year period prior to the end of 2005, sothat it would not be possible to reachattainment as of that time. However,implementation of these reductions bySeptember 2004, coupled with anynecessary additional reductions fromthe downwind sources, may result in nomore than one exceedance in thedownwind area during the attainmentyear and during each of the next 2 yearsthereafter. Under these circumstances,the downwind area would be eligible forthe 1-year extensions described aboveand would reach attainment by the year2007.

Similarly, full implementation bySeptember 2004 would mean thatsevere-17 areas would receive thebenefit of reduced upwind emissionsduring the 3-year period up to, andincluding, their 2007 attainment year. Inthe OTAG region, the severe-17 areas


3 Letter of January 29, 1997 from Jeffrey C. Smith,Executive Director, Institute of Clean AirCompanies, to Docket No. A–95–28: Acid RainProgram, Nitrogen Oxides Emission Reduction.

include the Philadelphia, New York,Milwaukee, and Chicago areas. Thesereductions should greatly assist thedownwind areas in reaching attainmentby the end of 2007.

An implementation date of betweenSeptember 2002 September 2004 is alsoconsistent with the attainment datescheme for the 8-hour NAAQS. The EPAintends to promulgate designations forareas under the 8-hour NAAQS by theyear 2000. The CAA provides forattainment dates of up to 5 years or 10years after designation. Therefore, thefirst attainment date for many areasunder the 8-hour standard could be2005. Section 172(a)(2)(C) has a two, 1-year extension scheme applicable forareas under the 8-hour NAAQS that issimilar to that described above, undersection 181(a)(5), applicable to areasunder the 1-hour NAAQS. Accordingly,full implementation of mandated SIPcontrols in the upwind areas by no laterthan September 2004 may allowdownwind areas to reach attainment ofthe 8-hour NAAQS by 2007, countingthe two 1-year extensions in the samemanner as for severe-15 areas under the1-hour NAAQS. In addition, the EPAbelieves that compliance no later thanSeptember 2004 by the utility andnonutility sector, with the emissionlimits assumed in setting the emissionbudgets or application of controls toother source categories, is feasible.

Further, EPA notes that the September27, 1994 OTC NOX Memorandum ofUnderstanding (MOU) provides thatlarge utility and nonutility NOx sourcesshould comply with the Phase IIIcontrols by the year 2003. The levels ofcontrol in the MOU are 75 percent or0.15 lb/106 btu in the inner and outerzones, levels comparable to the controlsassumed in setting the budget for thisrulemaking. In addition, in comments toEPA’s proposed Phase II NOx reductionprogram under the Acid Rain provisionsof the CAA 3, the Institute of Clean AirCompanies (ICAC) stated that more thansufficient vendor capacity existed tosupply retrofit of selective catalyticcontrol to the boilers affected by theproposed rule. The ICAC in factindicated that additional catalystcapacity could be added if needed.

Although EPA is proposing today thatSIPs mandate implementation of therequired SIP controls by a date withina range of September 2002 andSeptember 2004, EPA is also proposingthat the affected States demonstrateachievement of their NOX budgets as of

the end of the year 2007. In addition,EPA used the 2007 date to analyze formodeling purposes the impact ofupwind emissions on nonattainment airquality. Using the 2007 date means thatthe States will be able to account for theadditional reductions from Federalmeasures occurring between the datethat SIP controls are implemented andthe end of 2007, although the State mustalso account for growth in emissionsduring this time. Using the 2007 date issensible in part because OTAG used thisdate for these purposes and compiledsubstantial technical information—suchas information concerning inventories—based on this date. It is, therefore,efficient for EPA to use this sameinformation. Developing comparableinformation for an earlier date would betime consuming and resource intensive.In addition, it is uncertain that therewould be significant differences inamounts of emissions and impact onambient air quality between an earlierdate and 2007, in light of the fact thatduring this period, emissions wouldgenerally increase somewhat as a resultof growth in activities that generateemissions, but would also decrease dueto continued application of federallymandated controls. Accordingly,requiring accounting for a budget as ofthe 2007 date is both practicablyindicated and is a reasonable surrogatefor requiring this accounting as ofSeptember 2004.

E. Section 126 Petitions

The EPA has received section 126petitions from eight States: Connecticut,Maine, Massachusetts, New Hampshire,New York, Pennsylvania, Rhode Islandand Vermont. The petitions vary as tothe type and geographic location ofsources they identify as meriting afinding of significant contribution. Thepetitions also vary as to the levels ofcontrols they recommend. In addition,EPA has received a petition from theState of Wisconsin asking EPA topromulgate a SIP call under section110(k)(5) requiring the States of Illinois,Indiana, Iowa, Kentucky and Missourito submit SIP revisions addressing thepurported impact of their emissions onWisconsin. By letter dated August 8,1997, from Mary D. Nichols, AssistantAdministrator for Air and Radiation, toMichael J. Walls, Chief, EnvironmentalProtection Bureau, Office of theAttorney General, State of NewHampshire, EPA provided technicalguidance concerning section 126petitions. The EPA is now studying thepetitions and will prepare a notice(s) ofproposed rulemaking to grant or denythem.

The EPA’s response to a section 126petition differs from today’s action inseveral ways. Today’s action is aproposed SIP call under section110(k)(5) for SIP provisions meeting therequirements of section 110(a)(2)(D) forthe 1-hour ozone NAAQS, coupled witha proposed requirement under section110(a)(1) for submission of SIPprovisions meeting the requirements ofsection 110(a)(2)(D) for the 8-hour ozoneNAAQS. The EPA bases this action ona technical analysis as to whether theentire NOX emissions inventory of anindividual upwind State contributessignificantly to an ozone nonattainmentproblem downwind. If EPA concludesthat the NOX emissions from that Statemake such a significant contribution,EPA will require the State to submit SIPprovisions that limit the State’s NOX

emissions to the level mandated byEPA, but through any combination ofmeasures affecting any sector of theinventory chosen by the State. If theState does not make the requiredsubmission, EPA may, among otherthings, promulgate a FIP in accordancewith section 110(c).

By comparison, a section 126 petition,by the terms of section 126(b)–(c), islimited to upwind major stationarysources and not other sectors of theupwind emissions inventory. Moreover,a section 126 petition may seek afinding concerning upwind sources inmore than one State. Further, if EPAgrants the petition, it is EPA, and notthe States, that promulgates directcontrols for the major sources.

The EPA’s response to section 126petitions would bear relevance totoday’s action. The section 126 petitionsand section 110(k)(5)/110(a)(1) actionboth require technical analysis ofwhether upwind sources contributesignificantly to a downwindnonattainment or maintenance problem.However, EPA’s section 110(k)(5)/110(a)(1) action results in a mandate forthe States to submit SIP revisions thatconform to only minimum guidanceprovided by EPA. On the other hand,the section 126 petitions, if granted,would result in EPA selection andimposition of controls directly on majorstationary sources. These controls couldprovide a template for the SIPprovisions the States must include intheir rulemaking response to EPA’ssection 110(k)(5)/110(a)(1) rulemakingor, if necessary, a FIP.

EPA believes that both the 110process as outlined and 126 petitionprocesses are aimed at addressingregional transport of ozone formingpollutants and can be fully coordinated.The 110 process outlined provides thepotential to deal comprehensively with


4 Under the two alternative interpretations ofsection 110(a)(2)(D) that EPA is proposing today, ifupwind emissions meet the factors related toemissions and contribution to ambient air quality,EPA would conclude either that the emissionssignificantly contribute to a nonattainmentproblem, or the emissions may significantlycontribute, depending on further analysis of otherfactors, including costs.

transported pollutants that contributesignificantly to downwindnonattainment, and importantly, allowsindividual States to make choices aboutcost-effective source controls best fittingtheir unique State situations. The 126petition process provides assurance topetitioning States that upwind sourcesof air pollution will be addressed in atimely manner. Thus, each of theseprocesses may provide important andcomplementary tools to address theregional ozone transport problem.

Over the next several months, EPAwill be working with the affected Statesto ensure these two processes are fullycoordinated. This will providemaximum certainty for State andbusiness planning requirements. TheEPA’s goal in this effort will be toensure that States achieve the air qualityreductions EPA determines throughrulemaking are necessary to addressregional transport while providing themaximum flexibility to those States inidentifying the appropriate means tomeet those goals.

F. OTAG ProcessThe OTAG has completed the most

comprehensive analysis of ozonetransport ever conducted. The processhas resulted in more technicalinformation being gathered and moremodeling and monitoring analyses onregional ozone transport than everbefore. The OTAG process wasfundamentally different from previousefforts undertaken by the FederalGovernment and the States to assess andsolve air pollution problems. What wasunique about the multistate,multistakeholder OTAG process is thatfor the first time, the FederalGovernment has looked to the Statesinvolved to provide the necessarytechnical information and to aid indetermining an outcome which haslocal, regional and nationalimplications.

The OTAG was organized into anumber of subgroups and work groupsthat included members from the States,EPA, industry and environmentalgroups. The OTAG’s Policy Group,comprised of the State EnvironmentalCommissioners, provided overalldirection to its subgroups for theassessment of ozone formation andtransport, as well as the development ofcontrol strategies that will reduceconcentrations of ozone and itsprecursors. The subgroups withinOTAG addressed issues relating toemissions inventories, monitoring,modeling, and evaluated theavailability, effectiveness, and costs ofpotential national, regional and local airpollution control strategies. Specific

issues such as trading and market-basedincentives were also addressed.

The OTAG’s initial meetings were onMay 18, 1995, in Reston, VA, and June19, 1995, in Washington, DC. The OTAGcontinued to meet regularly for 2 yearsuntil their final meeting in Washington,DC on June 19, 1997. The goal of OTAGwas to:* * * identify and recommend a strategy toreduce transported ozone and its precursorswhich, in combination with other measures,will enable attainment and maintenance ofthe national ambient ozone standard in theOTAG region. A number of criteria will beused to select the strategy including, but notlimited to, cost effectiveness, feasibility, andimpacts on ozone levels. (1)

To meet its goal, OTAG usedtechnical information from air qualityanalyses and photochemical modeling.The OTAG modeled three rounds ofemission reduction scenarios andstrategies, including varying controlmeasures geographically. The firstround of modeling was performedduring September and October 1996 andprovided an initial evaluation ofpossible OTAG emission reductionscenarios. The second round wasperformed during November andDecember 1996 and refined theemission reduction level for thestrategies. The third round wasperformed during January throughMarch 1997 and evaluated thegeographic applicability of the OTAGstrategies. These geographic modelingruns provided information on applyingdifferent levels of controls on utilitiesand nonutility point sources atincremental steps. Round-3 alsoincluded a limited number of additionalmodeling runs needed to addresscomments made by a number of Statesrelated to the geographical boundariesof the zones defined for round-3modeling. The OTAG modeling resultsare discussed in section II, Weight ofEvidence Determination of SignificantContribution, and are also available onthe OTAG webpage. This modeling,along with other OTAG-generatedinformation, provided the technicalinformation necessary to makerecommendations to the Policy Groupand to EPA on what is needed to meetthe OTAG goal. The EPA receivedOTAG’s final recommendations on July8, 1997. These recommendations areincluded in Appendix B.

II. Weight of Evidence Determination ofSignificant Contribution

A. Introduction

This section documents the technicalinformation and analyses for the factorsconcerning emissions and contributions

to ambient air quality that EPA uses todetermine which States in the OTAGdomain make a significant contributionto nonattainment in downwind States.4To a large extent, this assessment isbased upon the results of OTAGmodeling and air quality analyses aswell as information from other non-OTAG modeling studies. The OTAGmodeling available for this analysisincludes a set of initial emissionssensitivity runs, the regional strategyruns in rounds 1, 2, and 3, and thegeographic sensitivity runs performed tosupport the design of strategies inround-3.

B. Background Technical Information

The importance of interstate transportto the regional ozone problem andcontributions from upwind States todownwind States is supported bynumerous studies of air qualitymeasurements and modeling analyses.In general, ozone episodes can occur onmany spatial and temporal scalesranging from localized subregionalevents lasting a day or 2, up toregionwide episodes lasting as long as10–14 days. The frequency of localizedversus regional episodes depends on thecharacteristics of the large-scalemeteorological patterns which controlthe weather in a particular summerseason. Local controls alone are notsufficient to reduce ozone duringregionwide episodes since a substantialamount of ozone may be transportedinto the area from upwind sources. TheNational Research Council report,‘‘Rethinking the Ozone Problem inUrban and Regional Air Pollution’’, (2)cites numerous studies of widespreadozone episodes during summertimemeteorological conditions in the East.These episodes typically occur when alarge, slow-moving, high pressuresystem envelopes all, or a large portionof, the Eastern United States. Therelatively clear skies normallyassociated with such weather systemsfavor high temperatures and strongsunlight, which enhances the formationof high ozone concentrations. Inaddition, the wind flow patterns canlead to a build up of ozoneconcentrations and the potential forlong-range ozone transport. Specifically,winds are generally light in the centerof high pressure systems so that areas


under the center may have near-stagnation conditions resulting in theformation of high ozone levels. As thehigh pressure system moves eastward,winds become stronger on the‘‘backside’’ which increases thepotential for these high ozone levels tobe transported to more distantdownwind locations. Over several days,the emissions from numerous small,medium and large cities, majorstationary sources in rural areas, as wellas natural sources, combine to form a‘‘background’’ of moderate ozone levelsranging from 80 to 100 ppb (2) of which30 to 40 ppb may be due to naturalsources. Concentration levels in therange of 80 to 100 ppb and higher havealso been measured by aircraft aloft,upwind of the Lake Michigan area (3),as well as the Northeast Corridor (4).Because this level of background ozoneis so close to the NAAQS, even a smallamount of locally-generated ozone willresult in an exceedance.

The importance of the episodicmeteorological conditions is heightenedby the spatial distribution of emissionsacross the region. The EPA hasexamined the State total emissions andemissions density projected by OTAG to2007, as described in section B.2, OTAGStrategy Modeling. Both of thesemeasures of emissions (i.e., total anddensity) are important considerationsfor ozone formation. Total emissionsindicate the amount of mass emitted bya State while emissions densityindicates the degree to which thoseemissions are concentrated within theState and provides a way to compareemissions between geographically largeand small States on a more equivalentbasis. The State total emissions in TableII–1 indicate that there is no single Stateor group of adjacent States that standout as the major contributors to the totalmanmade emissions in the OTAGregion. Rather, many States in theMidwest, Northeast and Southeast havehigh levels of emissions. For example,Illinois, Indiana, Ohio, Kentucky,Michigan, Pennsylvania, New York,Alabama, Georgia, Florida, NorthCarolina and Tennessee each have totalNOX emissions exceeding 1000 tons perday. Even some other smaller States likeConnecticut, Delaware, Maryland,Massachusetts, and Rhode Island, alongwith the District of Columbia, have ahigh spatial density of NOX emissions asindicated in Table II–2. Thus,considering the distribution ofemissions, a broad range of emissionsfrom many States contribute to theregional background ozone duringepisodic meteorological conditions. Inthis situation, there is a cumulative

effect in that the thousands of stationarysources and millions of motor vehiclesthroughout the OTAG regioncollectively cause downwindcontributions as they generate emissionsand those emissions interact overmultiple days.

1. OTAG Modeling ProcessAs described in the OTAG Modeling

Protocol (5), state-of-the-science modelsand data bases were used in OTAG forsimulating the physical and chemicalprocesses involved in the formation andtransport of ozone and precursor speciesover multiday episodes and regionalscales. As such, the OTAG modelingsystem provides the most complete,scientifically-credible tools and dataavailable for the assessment of interstatetransport. All of the OTAG model runswere made for an area covering a largeportion of the Eastern United States, asshown in Figure II–1. This area includesall or portions of 37 States, the Districtof Columbia and southern Canada. Ingeneral, the OTAG ‘‘modeling domain’’(i.e., OTAG region) was set large enoughto encompass the widespread spatialextent of high ozone levels measuredduring multiday episodes in the easternhalf of the United States. As such, thedomain is designed to handle thesynoptic (i.e., large) scale meteorologicalconditions associated with regionaltransport and to include the majoremissions source areas in the East. Thehorizontal grid configuration used byOTAG (see Figure II–1) includes a ‘‘FineGrid’’ at 12 km resolution ‘‘nested’’within a ‘‘Coarse Grid’’ at 36 kmresolution. The size and location of the‘‘Fine Grid’’ was determined based onthe location of areas with high ozoneconcentrations, the geographicvariations in emissions density, themeaningful resolution of some modelinputs, computer hardware limitations,and model run times. As described insection B.3, OTAG GeographicModeling, OTAG applied differentlevels of controls in the ‘‘Fine Grid’’versus the ‘‘Coarse Grid’’ as part of theround-3 modeling.

Four specific episodes were selectedby OTAG for model simulations in orderto provide information on a range ofmeteorological conditions which occurduring periods of elevated ozone levels.These episodes are: July 1–11, 1988;July 13–21, 1991; July 20–30, 1993 andJuly 7–18, 1995. Each of these episodesrepresents somewhat different episodiccharacteristics in terms of transportpatterns and the spatial extent of highozone concentrations in the East (6).The 1988 and 1995 episodes featuredhigh ozone concentrations in theNortheast, Midwest, and Southeast with

wind regimes that provided themeteorological potential for intra- andinter-regional transport. During the 1991episode, high ozone was confinedmainly to the northern portion of theOTAG domain, whereas the 1993episode was a ‘‘Southeast’’ episode withrelatively low ozone levels outside thisregion. It should be noted that none ofthe OTAG episodes include extensiveperiods of high ozone in the far westernportions of the domain nor in areasalong the gulf coast.

As part of OTAG, an objectiveevaluation of model predictions wasconducted for each of these fourepisodes in order to determine theperformance of the modeling system forrepresenting regional ozoneconcentration levels. This evaluationfocused on a number of statisticalmetrics comparing predicted ozone toground-level ozone measurements (7).The results indicate generally goodagreement between simulated andobserved values. Most importantly,areas of predicted high ozonecorrespond to areas of observed highozone. However, a few relatively minorconcerns were found, such as:

• A tendency to underestimateconcentrations in the North andoverestimate concentrations in theSouth;

• Concentrations at night aresomewhat underestimated relative todaytime predictions;

• Low observed concentrations tendto be overestimated and higher observedvalues tend to be underestimated; and

• Concentrations at the start of theepisode tend to be underestimated witha tendency for concentrations at the endof the episode to be overestimated.

The success of the model forpredicting pollutant concentrations aloftis also important from a transportperspective. During the day, when theatmosphere is ‘‘well mixed,’’ ground-level ozone values can serve as a goodmeasure of both local formation andtransport. However, at night, ozone isdepleted in a very shallow layer nearthe ground due to deposition andnighttime chemical reactions. Thus,during the overnight and early morning,ground-level measurements andpredictions do not adequately reflectpollutant transport. Aircraft-measuredpollutant data and model predictionsduring these periods indicate moderateto high levels of ozone aloft which canthen mix down during the day andfurther elevate ground-levelconcentrations. A limited amount ofmeasured data aloft are available fromnon-OTAG field studies for several ofthe days in the 1991 and 1995 episodes.An initial comparison of these data to


5 Although the OTAG assessments focussed on 1-hour concentrations, the impacts on 8-hr averageconcentrations were found to be similar to these for1-hour values.

the model predictions (6) indicates thatmodel performance aloft is not as goodas for ground-level ozone. In general,the model tends to underestimate ozonealoft. This suggests that the model maysomewhat underestimate the amount ofozone transport aloft, especiallyovernight into the early morning hours.Thus, the contribution of upwind sourceregions to ozone levels in downwindareas may actually be greater thanestimated by the model.

2. OTAG Strategy Modeling

The OTAG strategy modeling wasconducted in several phases. In eachphase, the effects on ozone 5 of variouschanges in emissions were examinedrelative to a future-year baseline. Thisbaseline reflects the projection ofemissions from 1990 to 2007. Includedin the 2007 baseline are the net effectsof growth and specific control programsprescribed in the 1990 Amendments.The control measures included in the2007 baseline are listed in Table II–3.Overall, domainwide emissions of NOX

in the 2007 baseline are approximately12 percent lower than 1990 whileemissions of VOC are approximately 20percent lower. The procedures fordeveloping the 1990 base inventory andthe 2007 baseline are described byPechan (8). The key findings (6) fromcomparing the model predictions for the2007 baseline to the 1990 base casescenario are:

• Ozone levels are generally reducedacross most of the region, includingnonattainment areas;

• Some increases in ozone arepredicted in areas where highereconomic growth is expected to occur,especially in the South;

• Ozone levels aloft along regional‘‘boundaries’’ are reduced, but averageconcentrations above 100 ppb and peakconcentrations above 120 ppb are stillpredicted on several days; and

• Ozone concentrations above the 1-hr and/or 8-hr NAAQS may still occurin the future under similarmeteorological conditions in many ofthe counties currently violating either orboth of these NAAQS.

The 2007 baseline emissions werereduced in an initial set of sensitivitymodeling performed to assess severalbroad strategy-relevant issues. All ofthese model runs involved ‘‘across-the-board’’ emissions reductions (i.e., nosource category-specific reductions).The results (6) of these simulations areas follows:

• Regional reductions in NOX

emissions decrease ozone across broadportions of the region including ozonein areas violating the NAAQS;

• Regional reductions in VOCemissions decrease ozone in and nearthe core portions of urban areas withrelatively small regional benefits;

• Both elevated and low-level NOX

reductions decrease ozoneconcentrations;

• NOX reductions can producelocalized, transient increases in ozone(mostly due to low-level, urban NOX

reductions) in some areas on some days;most increases occur on days and inareas where ozone is low (i.e., below theNAAQS);

• NOX plus VOC reductions lessenozone increases in urban areas, butprovide little additional regionalbenefits compared to NOX-onlyreductions; and

• The magnitude and spatial extent ofchanges in 8-hour ozone concentrationsare consistent with the changespredicted in 1-hour concentrations.

Based upon the findings of thesensitivity runs, OTAG subsequentlydeveloped and simulated source-specific regionwide control strategies intwo rounds of modeling. Thesestrategies were derived from a range ofcontrol measures applied to individualsource categories of VOC and NOX (8).The controls were grouped into variouslevels of relative ‘‘stringency’’ as listedin Tables II–4a and II–4b. The round-1and round-2 modeling consisted ofstrategies that contained variouscombinations of controls from the least(level ‘‘0’’) to most stringent (level ‘‘3’’)for each source category. The controllevels and domainwide emissionsassociated with these strategies aregiven in Tables II–5a and II–5b.

The round-1 modeling was a‘‘bounding analysis’’ with runs thatranged from the lowest level of controlon all source categories (Run 1) to thehighest level of control on all sources(Run 2). Runs 3 and 4b were includedto isolate the effects of the moststringent OTAG controls on utilitiesonly, versus this level of control on theother source categories. In the round-2modeling, eight runs were simulated toexamine the relative benefits ofprogressively increasing the level ofcontrol on utilities, under twoalternative levels of control applied toarea, nonroad and mobile sources. Theresults (6) of the round-1 and round-2modeling are given in Table II–6.

The findings from the round-1 andround-2 OTAG strategy modeling whichare particularly relevant to this analysisare:

• Clean Air Act programs will likelyprovide a reduction in ozoneconcentrations in many nonattainmentareas; however, some areas currently innonattainment will likely remainnonattainment in the future and new 8-hr nonattainment and/or maintenanceproblem areas may develop as a resultof economic growth in some areas;

• NOX reductions from elevated andlow-level sources are both beneficialwhen considered on a regional basis;and

• Further mitigation of the ozoneproblem will require regional NOX-oriented control strategies in addition tolocal VOC and/or NOX controlsnecessary for attainment in individualareas.

3. OTAG Geographic ModelingIn the round-1 and round-2 strategy

modeling, controls were applied acrossthe entire domain. In round-3, controlswere applied on a geographic basis inorder to assess the relative effects ofdifferent strategies in various portions ofthe region. Prior to developing thesestrategies, a series of sensitivity testswas conducted by OTAG to provideinformation on the spatial scales oftransport in order to help determinewhere to apply various levels of control.The most relevant tests are the‘‘subregional’’ modeling and the‘‘rollout’’ modeling. The base case forthese tests was the 2007 baselinescenario. In the subregional modeling,the domain was divided into the 12subregions shown in Figure II–2. Forone set of subregional modeling, allanthropogenic emissions wereeliminated from each subregion,individually in separate model runs.These runs, called the ‘‘zero-out’’subregional scenarios, were performedfor the 1988 and 1995 episodes. In asecond set of subregional modeling,emissions were reduced, but noteliminated in each subregion. The levelof reductions were 60 percent forelevated point-source NOX emissions,30 percent from all other sources ofNOX, and 30 percent from all sources ofVOC. These runs are referred to as the‘‘5c’’ subregional scenarios. The ‘‘5c’’scenarios were run for most, but not all,subregions for the 1988, 1991 and 1995episodes. In addition to looking atindividual subregions, there were runsfor 1988 and 1991 which applied the‘‘5c’’ reductions in subregions 5, 6, and9 (Figure II–2) combined in order todetermine the relative impacts ofexpanding the size of the area ofemissions reductions.

In the rollout modeling, the ‘‘5c’’emissions reductions were applied firstwithin selected areas and, then, outward


in incremental steps (rollouts) ofapproximately 200 km from these areas,in subsequent runs. Three majornonattainment areas in the region(Atlanta, the Lake Michigan Area, andNew York City) were selected by OTAGfor this type of modeling.

The results (6) of the OTAGgeographic modeling indicate thefollowing:

• Emissions reductions in a givenmultistate region/subregion have themost effect on ozone in that sameregion/subregion;

• Emission reductions in a givenmultistate region/subregion also affectozone in downwind multistate regions/subregions;

• Downwind ozone benefits decreasewith distance from the source region/subregion (i.e., farther away, less effect);

• Downwind ozone benefits increaseas the size of the upwind area beingcontrolled increases, indicating thatthere is a cumulative benefit toextending controls over a larger area;and

• Downwind ozone benefits increaseas upwind emission reductions increase(the larger the upwind reduction, thegreater the downwind benefits).

The round-3 strategies were based inlarge part on the results of thegeographical sensitivity runs. Thecornerstone of round-3 was a set ofgeographic ‘‘zones’’ (see Figure II–3)which was used to vary the level ofcontrol across the OTAG region. For themost part, OTAG focussed the round-3controls on zones in the ‘‘Fine Grid.’’This was based upon an analysisindicating that, in general, the greatestpotential for regional transport leadingto inter-state impacts of concern occurswithin the ‘‘Fine Grid’’ portion of theOTAG region. The individual zoneswere used to differentiate the impacts ofcontrols in and close to the three major1-hour nonattainment areas of the ‘‘FineGrid’’ (i.e., the Northeast Corridor,Atlanta, and Chicago/Milwaukee) versuscontrols in zones farther upwind ofthese areas. Specifically, in round-3various levels of utility and nonutilitycontrols were applied by zone indifferent runs. The level of control foreach strategy is given in Table II–7. Ingeneral (except for Run F), the round-3runs progressively increase the leveland spatial extent of utility andnonutility controls starting with thereference run (Run A) through the moststringent run (Run I). In addition, therewere a number of supplemental round-3 runs (6) performed using a modifiedversion of the zones. The most relevantof these were Runs CA and CB whichaltered the configuration of zones II, III,

and IV to correspond more closely to theborders of the OTR.

The results (6) of the OTAG round-3runs indicate the following:

• The greater the emissionsreductions the greater the ozone benefits(Run I was the most effective strategyand Run A the least);

• There was no bright-line betweenthe incremental application of controlsnor any leveling off of benefits with themore stringent controls;

• Increasing the spatial extent ofemissions reductions increases theamount and spatial extent of ozonebenefits downwind; areas fartherupwind may need a higher level ofcontrol to have a given effect in aparticular downwind area;

• In general, emissions reductions ina given zone have the greatest effectswithin that zone; but there are alsoimpacts on high ozone concentrations inother zones downwind;

• Emissions reductions in zones I, III,and V are ‘‘effective and necessary’’ (6)to reduce ozone in the Lake Michiganarea, the Northeast Corridor, andAtlanta, respectively which are theclosest downwind areas to each of thesezones;

• Emissions reductions in moredistant zones also help reduce ozone inthese three major nonattainment areas;emissions reductions in zone II benefitthe Northeast Corridor and the LakeMichigan area; emissions reductions inzone IV benefit Atlanta and the LakeMichigan area;

• Emissions reductions in zones IIand IV are also ‘‘effective andnecessary’’ (6) to reduce ozone in‘‘problem areas’’ within these zones(e.g., Birmingham, Nashville, Charlotte,Richmond, Louisville, and Cincinnati);

• When viewed on a regional basis, itmay be ‘‘difficult to geographicallydistinguish between control levels’’ (6)because there are ozone problem areasin every zone within the ‘‘Fine Grid’’and there are clearly interzonal impacts;

• Additional emissions reductions in‘‘Coarse Grid’’ States ‘‘are not veryeffective’’ (6) in reducing high ozonelevels downwind in problem areas ofthe ‘‘Fine Grid’’; and

• Although the OTAG assessmentsfocused on 1-hour concentrations, theimpacts on 8-hour averageconcentrations were found to be similarto those for 1-hour peak values,suggesting that ‘‘a regional strategydesigned to help meet’’ the 1-hourNAAQS ‘‘will also help meet’’ the 8-hour NAAQS (6).

Overall, the findings from the OTAGsensitivity and strategy modelingindicate that:

• Areas of high ozone, both measuredand predicted for the future, occur, orwill occur, in most portions of themodeling domain;

• Several different scales of transport(i.e., inter-city, intra-state, inter-state,and inter-regional) are important to theformation of high ozone in many areasof the East;

• The greatest potential for inter-stateand inter-regional impacts associatedwith transport occurs between Stateswithin the multistate ‘‘Fine Grid’’ area;

• A regional strategy focussing onNOX reductions across a broad portionof the region will help mitigate theozone problem in many areas of theEast;

• There are ozone benefits across therange of controls considered by OTAG;the greatest benefits occur with the mostemissions reductions; there was no‘‘bright line’’ beyond which the benefitsof emissions reductions diminishsignificantly;

• Even with the large ozonereductions that would occur if the moststringent controls considered by OTAGwere implemented, there may stillremain high concentrations in someportions of the OTAG region;

• A regional NOX emissionsreduction strategy coupled with localNOX and/or VOC reductions may beneeded to enable attainment andmaintenance of the NAAQS in thisregion.

It should be noted that urban-scaleanalyses will be necessary in order forStates to develop local attainment plans.These analyses will take into accountmore geographically refined emissionsand local meteorological factors, such aslake and sea breezes and/or topography.Urban-scale modeling is also necessaryto more precisely evaluate the degreeand extent of any NOX disbenefit.

4. Other Relevant AnalysesIn addition to the OTAG modeling

described above, the potential forregional ozone transport has beenexamined by the OTAG Air QualityAssessment Work Group usingtrajectory analyses, wind vectorcharacterization, and statistical analysesof ozone measurements. The trajectoryanalyses (9) were used to identify a‘‘distance scale’’ indicative of the 1- to2-day transport distance of ozone andprecursors. The results suggest thatozone-laden air may travel distances of150 miles to 500 miles or more into andacross the Midwest and Northeast.Analyses, as part of the SouthernOxidants Study (10), indicate that mostsouthern episodes may be more closelylinked to near-stagnation conditions andthus, shorter transport distances might


be expected within the Southeast.Additional information on regionaltransport patterns comes from ananalysis conducted by OTAG tocharacterize the regional wind flowpatterns typically associated with highozone in the Northeast, Southeast, andMidwest (9). These wind vectors (FigureII–4) indicate that regional episodes aretypically associated with broad-scaleanticyclonic (i.e., clockwise) flowregimes centered over the Ohio-Tennessee Valley area. Under theseconditions, there are typically lighterwinds and weaker transport within theSouth compared to other regions.However, the information also indicatesthe potential for transport from theSouth to other portions of the region.For example, in the Midwest, highozone is generally associated with windflows from States located to the southand southwest. For the Northeast, thedata suggest a strong westerly flowfavoring transport from States farther tothe west.

Another method for estimating thepotential range of transport wasdeveloped by Rao (11) based oncorrelating daily ambient ozonemeasurements between monitoring sitesfor the period 1985 through 1994 forseveral nonattainment areas (i.e.,Atlanta, Washington DC, Cincinnati,Pittsburgh and Chicago). The analysisindicates the presence of ‘‘ozoneclouds’’ surrounding these areas whichare likely the result of pollutanttransport, spatial patterns in emissions,and weather conditions conducive toozone formation. The spatial extent ofthese ‘‘ozone clouds’’ is on the order of300 miles or more, extending from thecentral portion of the nonattainmentarea along the axis of the majortransport direction.

The importance of mitigatingtransported ozone for solving thenonattainment problem for many citiesin the East has been examined as partof ongoing urban scale modelinganalyses by various State agencies. Inurban scale modeling, transport into thenonattainment area is represented byspecifying pollutant concentrationsalong the sides and top of the modelingdomain. These ‘‘boundary condition’’concentrations reflect ozone transportinto the urban area at the surface andaloft. As such, incoming ozone (as wellas precursor chemical species) movesinto the urban area and mixes with localemissions to increase the formation ofozone. The available urban scalemodeling work is summarized in areport commissioned by OTAG (12). Itshould be noted that these modelinganalyses were conducted to address 1-hour attainment problems. Still, the

information is expected to be generallyapplicable to 8-hour ozoneconcentrations as well. The findingsfrom this report which are relevantinclude:

• New York City—a reduction intransport into the New York areaassociated with upwind emissionsreductions on the order of 75 percent forNOX and 25 percent for VOC along withlocal VOC and NOX reductions may beneeded for attainment in New York;

• Philadelphia—transport appears tobe a major component in peak ozoneconcentrations in the Philadelphiadomain, contributing 90 percent to thepeak in one of the scenarios modeled;

• Lake Michigan—transported ozonelevels coming into the Lake Michiganarea contribute 40–60 percent to thepeak concentration downwind of urbancenters in this area; backgroundconcentrations in the range of 80–100ppb may need to be reduced to around60 ppb for attainment in this region;

• Southeast Michigan—ozonetransport into this area ‘‘contributedsignificantly to the simulated peakozone concentrations on many of theepisode days;

• St. Louis—predicted ozoneconcentrations in this area are sensitiveto incoming levels of ozone/precursortransport;

• Atlanta—the amount of ozonetransported into the area was found tobe one of the factors contributing to thedifficulty for this area to demonstrateattainment;

• Richmond—transported ozonecontributes to predicted high ozone oncertain episode days, and regionalcontrols on upwind sources may benecessary to reduce ozone in this areaduring some of the episode daysmodeled;

• Charlotte—transported ozoneappears to be a ‘‘significant component’’of ozone in the area during someepisodes, particularly with winds froma northerly direction; and

• Nashville—transported ozone waspredicted to be a major contributor toozone in this area on 1 of the 2 highozone days modeled.

In addition to the precedingqualitative analyses, there are severalnon-OTAG regional modeling analyseswhich provide information on interstatecontributions due to transport. First,modeling by EPA for the OTC, using theRegional Oxidant Model (ROM),examined the impact of controls outsidethe OTR on ozone within thisregion (13). The results indicate that a0.15 lb/MMBtu NOX emissions limit oncertain stationary sources outside theOTR, together with other controls,

would likely have the following effectswithin the OTR:

• Reductions of up to 15–18 ppb indaily maximum 1-hour ozone in thewestern part of the OTR, and

• Reductions of up to 6–9 ppb alongthe Northeast Corridor fromWashington, DC to northern New Jersey.

Second, a new modeling technique,the ‘‘Comprehensive Air-quality Modelwith extensions’’ (CAMx), has beendeveloped (14) in an attempt to identifythe contribution of upwind source areasto specific downwind locations. TheOzone Source ApportionmentTechnology (OSAT) in CAMx was usedby the Midwest Ozone Group (MOG) toquantify the contributions of emissionsfrom upwind sources on high ozoneconcentrations in the Northeast Corridorand the Lake Michigan area. The CAMxanalysis modeled the OTAG July 1991episode only and considered 1-hourozone predictions above two cut-points:100 ppb and 120 ppb. Also, the MOGCAMx report (14) did not examine thecontributions from emissions inindividual upwind States, but rather,the analysis examined the impacts ofemissions from concentric geographic‘‘rings’’ upwind of the NortheastCorridor and Lake Michigan areas. Ingeneral, the results are consistent withthe OTAG geographic sensitivitymodeling in that much of thecontribution to ozone in a particularmultistate area comes from sourceswithin that same multistate area,considerable contributions also comefrom sources outside the multistate area,and anthropogenic NOX emissions inupwind areas contribute much more totransport than upwind VOC emissions.Some of the findings from the CAMxanalysis relative to the contributions tohigh ozone in the Northeast Corridorand Lake Michigan area are as follows:

• On average, nearly 50 percent of thehigh ozone levels in these two areascome from upwind (mostly NOx)sources;

• On average, for the NortheastCorridor a large portion (90 percent) ofthe contribution from upwind sourcescomes from States to the west and southwithin approximately 390 km of theCorridor (this may include all orportions of States as far upwind as Ohio,North Carolina, and West Virginia);nearly all (95 percent) of thecontribution comes from upwindsources within approximately 570 km ofthe Corridor (this may add portions ofKentucky, Tennessee, and SouthCarolina as potential upwindcontributors);

• On average, for the Lake Michiganarea a large portion (90 percent) of thecontribution from upwind sources


comes from States to the west andsouthwest within approximately 650 kmof this area (this may include all orportions of States as far as Iowa,Minnesota, Missouri, and Tennessee);nearly all (95 percent) of thecontribution comes from upwindsources within approximately 770 km ofthe Lake Michigan area (this addsportions of Arkansas, Kansas, Nebraska,North Dakota, and South Dakota); and

• Transport distances for individualhigh ozone days are even longer, insome cases, than the episode averagesindicated above.

A third non-OTAG modeling studythat is relevant to this assessment wasperformed by a group of northwestOTAG States (Iowa, Minnesota,Nebraska, North Dakota, and SouthDakota) (15). One part of this studyincluded modeling similar to the OTAGsubregional modeling, except that ‘‘zero-out’’ and ‘‘5c’’ emissions reductionswere applied in various combinations inthese States only, using the OTAG July1995 episode. In these runs, emissionsin all other States in the OTAG regionwere simulated with the 2007 baselineemissions. The modeling results wereanalyzed in terms of the contributions ofemissions in these five States to dailymaximum 1-hour ozone above 100 ppbin downwind areas. The results indicatethe following:

• Emissions in Minnesota, Nebraska,North Dakota, South Dakota, and the‘‘Coarse Grid’’ portion of Iowa (seeFigure II–1) collectively contribute lessthan 2 ppb to downwind ozone above100 ppb; and

• Emissions from these Statesincluding the ‘‘Fine Grid’’ portion ofIowa, contribute in the range of 2 to 6ppb to ozone above 100 ppb in grid cellsdownwind near Lake Michigan, Detroit,and Cincinnati.

Collectively, the studies cited hereindicate that:

• The meteorological conditions andair trajectories during regional-scale,high ozone episodes provide thepotential for multistate ozone transport;

• Ambient measurements indicatethat ozone episodes can have a largemultistate spatial extent within which1-to 2-day transport may occur;

• Examination of emissions dataindicates that numerous sources of NOX

may be contributing to high regionalbackground ozone concentrations;

• State urban-scale modeling analysesfor areas in various portions of theOTAG region indicate that transportfrom upwind areas is an impediment toattainment of the NAAQS;

• Regional modeling studies indicatecontributions to high ozone in theNortheast Corridor and the Lake

Michigan area may come from States asfar away as 570 km and 770 km,respectively; and

• Non-OTAG multistate modelingindicates that emissions from States inthe northwest portion of the ‘‘CoarseGrid’’ may not make large contributionsto high ozone in downwind Stateselsewhere in the OTAG region.

C. Technical Analysis of SignificantContribution

1. Criteria for Determining SignificantContribution

Whether a contribution is‘‘significant’’ depends on the overallcontext. There may be no single amountof contribution which could beconsidered as a bright line indicator of‘‘significant’’ that would be applicableand appropriate in all circumstances. Asdescribed above, under oneinterpretation of the CAA’s section110(a)(2)(D), factors to be considered indetermining whether a contribution issignificant include:

• The level of emissions in the areaupwind of a nonattainment area;

• The amount of the contribution(ppb above the level of the standard)made to the downwind nonattainmentarea;

• The transport distance between theupwind source area and the downwindproblem area; and

• The geographic extent of thecontribution downwind. For example,ozone is generally the result ofemissions of NOX and VOC fromhundreds of stationary sources andmillions of vehicles, each of which islikely to be responsible for much lessthan 1 percent of the overall inventoryof precursor emissions. A source orgroup of sources should not beexempted from treatment as asignificant contributor merely because itmay be a small part, in terms of totalemissions, of the overall problem whenall or most other contributors,individually, are also relatively smallparts of the overall problem. Thissituation, in which a number ofindividual (and sometimes small)sources collectively cause a significantimpact, is a major aspect of thecontribution issue. The moderate-to-high ozone levels which cover broadregions are the result of emissions frommillions of individual sourcesinteracting over multiple days. Thecontribution to downwindnonattainment results from thecumulative contribution from allsources involved in this process. Giventhese issues, it is not appropriate todefine a bright line test for ‘‘significantcontribution.’’ Rather, EPA is using a

‘‘weight of evidence’’ approach, basedon a range of information, fordetermining whether a State makes asignificant contribution to downwindnonattainment. The EPA is alsoproposing a second, alternativeinterpretation to section 110(a)(2)(D),under which the weight of evidenceapproach incorporates other factors,including the relative costs ofcontrolling downwind emissions, asdescribed in section I.D.2.b., SignificantContribution to Nonattainment.

2. Overview of Technical ApproachThe findings from the relevant

background studies and the OTAGmodeling results provide a basis forconcluding that ozone transport resultsin interstate contributions to high ozonelevels during multiday episodicconditions within portions of the OTAGregion. An overview of the approach foranalyzing this information in anassessment of States that make asignificant contribution to downwindnonattainment is as follows:

• The air quality and modelinganalyses cited in section B.4, OtherRelevant Analyses, were considered in aqualitative manner to identify, from aregional perspective, States which maycontribute to multistate transport;

• The results of the OTAGsubregional modeling runs were used toquantify the extent that each subregioncontributes to downwind nonattainmentfor the 1-hour and/or 8-hour NAAQS;and

• State NOX emissions data were usedto translate the findings from thesubregional modeling to a State-by-Statebasis.

The specific model runs used in thisanalysis include the ‘‘zero-out’’ runs inwhich all anthropogenic emissions fromindividual subregions (comprised ofportions of small groups of States) areremoved, and the contributions todownwind ozone are predicted. This setof model runs was chosen since itprovides an appropriate way to quantifythe contribution of the full set ofanthropogenic emissions in one area toozone concentrations in another. Asdescribed in section B.2, OTAG StrategyModeling, zero-out runs were made forthe 1988 and 1995 episodes only. Theresults for both episodes were combinedin this assessment. Also, the analysis ofemissions data focussed on NOX sincethe OTAG and non-OTAG modelingresults indicate that NOX emissionsreductions lower ozone transport acrossbroad portions of the OTAG region,whereas, VOC emissions reductionshave primarily local benefits.

The air quality, modeling, andemissions information was used


6 Values above 124 ppb are considered to beexceedances of the 0.12 ppm 1-hour ozone NAAQSin view of the rounding convention established formonitoring data whereby ozone concentrationsbetween 125 ppb and 129 ppb are rounded up to0.13 ppm.

collectively to determine, based on theweight of evidence, which States makea significant contribution to downwindnonattainment.

3. Identification of Ozone ‘‘ProblemAreas’’

As described above, in order toquantify the contribution from upwindStates to nonattainment downwind,EPA identified areas which currentlyhave a 1-hour and/or 8-hour ozonenonattainment problem and areexpected to continue to have anonattainment problem in the future,based on modeling. In addition, EPAconsidered areas which may have afuture maintenance problem for the 8-hour NAAQS. For currentnonattainment areas, EPA used airquality data for the period 1993 through1995 to determine which counties areviolating the 1-hour and/or 8-hourNAAQS. These are the most recent 3years of fully quality-assured datawhich were available in time for thisassessment. A list of these counties isprovided in Tables II–8a and II–8b. TheEPA is reviewing more recent air qualitydata for 1996 and 1997. In the event thatthese data alter the results of thisassessment in any meaningful way, EPAwill make the appropriate adjustmentsto the findings. Concerning projectedfuture nonattainment areas, EPA usedthe OTAG model predictions for the2007 baseline, as described in sectionII.C.5, Approaches for AnalyzingSubregional Modeling Data. For ease ofcommunication, the technicaldiscussions frequently use the term‘‘nonattainment’’ to refer to these areas.It should be noted that this use of theterm ‘‘nonattainment’’ in reference to aspecific area is not meant as an officialdesignation or determination as to theattainment status of the area.

4. Analysis of Air Quality, Trajectory,and Non-OTAG Modeling Information

The EPA examined the findings fromthe air quality, trajectory, and non-OTAG modeling analyses in section B.4.to identify certain States which maypotentially contribute to nonattainmentin downwind areas. First, EPA appliedboth the lower and upper ends of theOTAG transport distance scale (i.e., 150miles and 500 miles (9)) to 1-hournonattainment areas in the northern halfof the OTAG region. Using the lowerend of the transport scale indicates thatthe following States and Washington DCmay potentially contribute to ozone indownwind nonattainment areas:Connecticut, Delaware, Illinois, Indiana,Kentucky, Maine, Maryland,Massachusetts, Michigan, NewHampshire, New Jersey, New York,

Ohio, Pennsylvania, Rhode Island,Tennessee, Virginia, West Virginia,Wisconsin and Vermont. Using theupper limit of transport distanceindicates that the following additionalStates may potentially contribute todownwind nonattainment areas:Alabama, Arkansas, Georgia, Iowa,Kansas, Minnesota, Mississippi,Missouri, Nebraska, North Carolina,Oklahoma and South Carolina. Also,examining the findings from the non-OTAG regional modeling results (13, 14,15) indicates that collectively, a largeportion of the contributions to highozone in the Northeast Corridor and/orthe Lake Michigan area may come fromStates as far upwind as: Missouri, NorthCarolina, Ohio, Tennessee and WestVirginia.

5. Approaches for AnalyzingSubregional Modeling Data

The subregional modeling runsprovide a method to quantify theamount of contribution by upwindStates to downwind nonattainment.Four approaches were included in theanalysis of subregional modelingresults. Approaches 1 and 2 weredesigned to address the contribution to1-hour nonattainment and Approaches 3and 4 the contribution to 8-hournonattainment. Approaches 1 and 3examine the contributions in areaswhich have both monitored andmodeled nonattainment. Approaches 2and 4 examine the contributions inareas with modeled nonattainment. Therationale for each approach is describedbelow.

a. Approaches for 1-HourNonattainment. Approach 1 wasdesigned to focus on contributions toareas that have an observed 1-hourozone problem and in which the modelpredicts an ozone problem. In thisregard, the analysis was restricted tothose grid cells in the domain that had1-hour daily maximum ozonepredictions ≥125 ppb 6 in the 2007baseline, and were within one of thecounties currently violating the 1-hourNAAQS. However, the requirement thathigh ozone predictions spatiallycoincide with violating counties may beoverly restrictive given the uncertaintiesin the modeled wind regimes associatedwith the regional nature of themeteorological inputs. Also, the analysiswas limited to only two episodes, onlyone of which, July 1995, actuallyoccurred during the 3-year period used

to identify the violating counties.Another limitation of Approach 1 wasthat it excludes all grid cells that areover water and not touching any Stateland areas. This may be too restrictivesince, in the real atmosphere, sea breezeand lake breeze wind flows cantransport high ozone levels that occurover water back on-shore to affectcoastal land areas. This meteorologicalprocess, often associated with highozone along the shoreline of LakeMichigan and along the New Englandcoast, is not adequately treated by theregional scale meteorological inputsused in OTAG. Thus, highconcentrations predicted just offshoremay be inappropriately excluded fromthe analysis. Approach 2 was designedto address these concerns. In thisapproach, all grid cells over land thathad a 1-hour daily maximum ozoneprediction ≥125 ppb in the baselinewere included. Also included were gridcells with predictions ≥125 ppb overeach of the Great Lakes and in a band60 km (5 grid cells) wide along the EastCoast.

b. Approaches for 8-HourNonattainment. The two approaches forassessing contribution for 8-hournonattainment were similar in design tothose used for 1-hour nonattainment.However, the inconsistency between theform of the 8-hour NAAQS, whichconsiders 3 years of data, and thelimited predictions available from theOTAG episodes introduced acomplication to the analysis. Basically,it was not possible to use the modelpredictions in a way that explicitlymatches the 3-year average of the 4thhighest 8-hour form of the NAAQS.Instead, an analysis was performed tolink the model predictions to theNAAQS as closely as possible. Thisanalysis consisted of comparing theaverage 4th highest 8-hourconcentrations, based on 3 years ofambient data, to the average 1st, 2nd,3rd, and 4th highest 8-hour values usingambient data limited to the three mostrecent OTAG episodes (i.e., 1991, 1993,and 1995). The results of this analysisindicate that the average of the episodic2nd highest 8-hour ozone concentrationcorresponds best, overall, to the averageof the 4th highest 8-hour NAAQS.

Approach 3 is intended to focus onthe contributions to areas that have anobserved 8-hour ozone problem andwhere the model predicts an 8-hourozone problem. The analysis for thisapproach was restricted to those gridcells in the domain that had an average(over the 1988 and 1995 episodes) 2ndhigh 8-hour ozone prediction ≥85 ppb inthe 2007 baseline, and were within oneof the counties currently violating the 8-


hour NAAQS. The same technicalconcerns and limitations discussedabove for Approach 1 are alsoapplicable to Approach 3. To addressthese concerns for the 8-hour analysis,Approach 4 was constructed to includeall grid cells that had an average 2ndhigh 8-hour ozone prediction ≥85 ppbover land areas, the Great Lakes, and inthe offshore waters, as in Approach 2 forthe 1-hour NAAQS. In addition, byincluding all grid cells with predictednonattainment in 2007, Approach 4provides a way to consider areas whichare currently measuring attainment, butwhich may become nonattainment forthe 8-hour NAAQS in the future.

c. Methods for Presenting 1-Hour and8-Hour Assessments. All of theapproaches for both 1-hour and 8-hournonattainment quantify the impacts ofemissions in each subregion on ozoneconcentrations in downwind States (i.e.,States outside the particular subregion).It should be noted that the calculatedcontributions represent the impactsfrom individual upwind subregions andnot the cumulative impacts frommultiple subregions, which would beeven greater in magnitude. InApproaches 2 (1-hour) and 4 (8-hour),grid cells off the East Coast were addedto the totals of the adjacent States,whereas the impacts for areas over eachof the Great Lakes were tabulatedseparately. In all cases, the ozoneimpacts were quantified by calculatingthe difference in predicted ozonebetween each subregional zero-out runand the 2007 baseline scenario. Thecontributions from emissions in eachsubregion to nonattainment indownwind States are summarized for allapproaches in Tables II–9a and II–9b.This summary shows the contributionsin terms of both the frequency ofimpacts and the number of downwindStates impacted for specificconcentration ranges, as describedbelow. More detailed informationincluding the contributions toindividual States is provided in TablesII–10 through II–13, for Approaches 1through 4, respectively. Thecontributions are grouped into one ofsix ranges: >2 to 5 ppb, >5 to 10, >10to 15, >15 to 20, >20 to 25, and >25 ppb.A value of 2 ppb was chosen as theminimum level for this analysisfollowing the convention generally usedby OTAG for evaluating the impacts ofemissions changes. As an example,Table II–10 shows the frequency ofcontributions from each subregion tononattainment in downwind States forApproach 1. Note that the frequency ofcontributions for the 1-hour NAAQS isdetermined by tallying the total

‘‘number of days and grid cells’’ withimpacts within the specified range.However, the frequency of contributionsfor the 8-hour NAAQS includes the total‘‘number of grid cells’’ only. That is, theaveraging procedure used to reflect theform of the 8-hour NAAQS results in asingle ‘‘average’’ value for each grid cell,instead of values for each day modeled.In the following sections, Approach 1and Approach 3 are referred to as the‘‘violating-county’’ approaches, whereasApproach 2 and Approach 4 are referredto as the ‘‘all grid-cell’’ approaches forthe 1-hour and 8-hour NAAQS,respectively. Also, as mentionedpreviously, the term ‘‘nonattainment’’ isused to refer to those areas (grid cells)which meet the criteria for a givenapproach. For example, in the analysisof Approach 1, ‘‘nonattainment’’ refersto those areas which have bothmeasured violations and modelpredictions of 1-hour ozone ≥125 ppb.

6. Contributions to 1-HourNonattainment

The information from the subregionalmodeling analyses provided in TablesII–10 and II–11 were examined fromboth a ‘‘receptor’’ and ‘‘source’’perspective. The results for the ‘‘county-violation’’ approach (Approach 1—Table II–10) and the ‘‘all grid-cell’’approach (Approach 2—Table II–11) areboth considered. Examining the data inTable II–10 indicates that manynonattainment areas are affected bymultiple source areas. Considering theimpacts on violating counties indicates,for example, that:

• Nonattainment areas inPennsylvania receive contributions ofmore than 2 ppb from Midwest andSoutheast States located in fivesubregions (2, 5, 6, 7, and 8) withcontributions over 25 ppb from States insubregions 6 and 7;

• Nonattainment areas in New Jerseyreceive contributions of more than 2ppb from Midwest States as well asadjacent States in six subregions (1, 2,3, 5, 6, and 7) with contributions over25 ppb from subregions 3 and 7;

• Nonattainment areas in Marylandreceive contributions of more than 2ppb from Midwest States and adjacentStates in six subregions (1, 2, 3, 4, 5, and6) with contributions in the range of 15to 20 ppb from subregions 3 and 6;

• Nonattainment areas in Illinoisreceive contributions of 5 to 10 ppbfrom Southeast States in subregion 9;and

• Nonattainment areas in Georgia andAlabama receive contributions of 15 to20 ppb from Midwest States insubregion 5 as well as from adjacentSoutheast States in subregion 8.

Considering the ‘‘all grid cell’’approach increases the frequency andmagnitude of impacts, as would beexpected. For example, thecontributions from States in subregion 2to nonattainment in Pennsylvaniaincrease to the range of 10 to 15 ppb;contributions from Southeast States insubregion 9 in the range of 2 to 5 ppbare evident in nonattainment inMaryland; and Midwest States insubregions 1 and 5 contribute 5 to 10ppb to nonattainment in Ohio.

As indicated above, the subregionalmodeling results were also examined interms of the impact of each subregion onozone in downwind States outside theparticular subregion. The followingresults highlight the contributions ofeach subregion to downwindnonattainment (see Tables II–10 and II–11). Results are presented for the‘‘violating county’’ approach (Approach1) and supplemented with results fromthe ‘‘all grid-cell’’ approach (Approach2) to the extent that this later approachadds key information to the findings.

Subregion 1 (portions of Illinois,Wisconsin, Indiana, and Iowa):emissions in this subregion contribute 2to 5 ppb on numerous occasions tononattainment in violating counties infour States along the Northeast Corridorhaving serious or severe nonattainment(i.e., Connecticut, Maryland, NewJersey, and New York); downwindcontributions as high as 5 to 10 ppb areevident near Detroit over Lake St. Clair,as well as over Lakes Erie and Ontariobased on the ‘‘all grid-cell’’ approach.

Subregion 2 (portions of Michigan,Indiana, and Ohio): emissions in thissubregion contribute 5 to 10 ppb tononattainment in violating counties infive downwind States; contributionsover 10 ppb are evident in sevendownwind States from the ‘‘all grid-cellapproach.’’

Subregion 3 (portions ofPennsylvania, New York and Delaware):emissions in this subregion contributeover 2 ppb to violating counties in ninedownwind States with contributions of15 ppb or more in three States.

Subregion 4 (New Jersey, Connecticutand portions of New York, Pennsylvaniaand Delaware): emissions from thissubregion contribute more than 25 ppbon numerous occasions to threedownwind States along the NortheastCorridor.

Subregion 5 (portions of Illinois,Indiana, Kentucky, Missouri, andTennessee): emissions from thissubregion contribute 2 to 5 ppb toviolating counties in three downwindStates along the Northeast Corridor withcontributions of over 10 ppb in threeother downwind States in the region;


considering the ‘‘all grid-cell’’ approachshows contributions of over 20 ppb tothe south in Alabama and 5 to 10 ppbover Lakes Erie and St. Clair.

Subregion 6 (portions of Ohio,Indiana, Kentucky, Tennessee, WestVirginia and Virginia): emissions in thissubregion contribute over 5 ppb toviolations in eight States (and as fardownwind as Massachusetts with the‘‘all grid-cell’’ approach); contributionsover 15 ppb are predicted in two of theeight States.

Subregion 7 (Maryland, Washington,DC, and portions of Delaware, NorthCarolina, Virginia and West Virginia):emissions in this subregion contributemore than 15 ppb to violating countiesin downwind States along the NortheastCorridor with over 25 ppb contributionon numerous occasions to two of theseStates; the ‘‘all grid-cell’’ approachindicates contributions from thissubregion to South Carolina as well asto Kentucky and Ohio.

Subregion 8 (portions of NorthCarolina, South Carolina and Georgia):emissions in this subregion contribute 2to 5 ppb to violating counties in fourStates including several which arerelatively far downwind (i.e., Missouriand Illinois) with contributions over 15ppb to one other State; considering the‘‘all grid-cell’’ approach indicatescontributions of over 10 ppb to twoStates along the Northeast Corridor.

Subregion 9 (portions of Tennessee,Georgia, Alabama, Mississippi, Northand South Carolina and Arkansas):emissions in this subregion contributeover 2 ppb to violating counties in fourdownwind States with contributionsover 10 ppb in Indiana; contributionsover 10 ppb are evident in threedownwind States and far away as LakesMichigan from the ‘‘all grid-cell’’approach.

Subregion 10 (Florida and portions ofMississippi, Alabama, Georgia andLouisiana): emissions in this subregiondo not contribute above 2 ppb toviolating counties in any other States;considering the ‘‘all grid-cell’’ approachindicates one occurrence of acontribution in the range of 2–5 ppb.

Subregion 11 (portions of Texas,Louisiana, Arkansas and Oklahoma):emissions in this subregion contribute 2to 5 ppb to violating counties in twodownwind States.

Subregion 12 (portions of Missouri,Iowa, Wisconsin, Minnesota, NorthDakota, South Dakota, Nebraska, Kansasand Oklahoma): emissions in thissubregion contribute 2 to 5 ppb inviolating counties in two downwindStates with 5 to 10 ppb contributionsalso evident in one of these States (i.e.,Michigan, including Lake Michigan).

The results presented in Tables II–10and II–11, and discussed above, indicatethat in general, large contributions todownwind nonattainment occur onnumerous occasions even though theanalysis was limited to only twoepisodes. Although the level ofcontribution varies from subregion tosubregion, a consistent pattern isapparent. In view of the relatively highmagnitude of the contributions, and/orthe relatively high frequency of thecontributions, and/or the distancedownwind to which the contributionsoccur, and/or the geographic extent ofthe downwind contributions, EPAbelieves that emissions from subregions1 through 9 make a marked contributionto 1-hour nonattainment in numerousdownwind States. Contributions todownwind nonattainment were alsoevident from subregions 10, 11, and 12,although to a lesser magnitude andextent.

7. Contributions to 8-HourNonattainment

In general, the downwindcontributions to 8-hour nonattainmentare more geographically extensive thanthose for 1-hour nonattainment. This isnot unexpected because there are manymore violating counties for the 8-hourNAAQS and, likewise, the modelpredicts ‘‘nonattainment’’ over a muchbroader portion of the region. Thefollowing examples illustrate the extentand magnitude of contributions toviolating counties (Approach 3—TableII–12) that are beyond what was foundfor the 1-hour assessment:

• Contributions to nonattainmentareas in Pennsylvania from States insubregion 2 are over 25 ppb rather than2 to 5 ppb;

• In addition to the contributionsfrom States in subregions 1, 2, 3, 5, 6,and 7 (ranging up to 15 to 20 ppb fromsubregion 3), nonattainment areas inNew Jersey also receive a 2 to 5 ppbimpact from southeastern States insubregion 8;

• Nonattainment areas in Illinoisreceive contributions of 5 to 10 ppbfrom States to the east in subregion 6and south in subregion 9;

• Nonattainment areas in Ohioreceive contributions of 5 to 10 ppbfrom States in five subregions in theMidwest, Northeast, and Southeast (1, 3,5, 7, 8, 9) with contributions over 10ppb from States in subregion 5;

• Nonattainment areas in NorthCarolina receive contributions of 5 to 10ppb from two subregions (7 and 9) withcontributions of over 25 ppb fromMidwest States in subregion 6; and

• Nonattainment areas in Tennesseereceive contributions of 10 to 15 ppb

from three subregions (5, 6, and 8) with15 to 20 ppb contributed by MidwestStates in subregion 6.

Highlights of the 8-hour contributionsfrom a ‘‘source’’ perspective are givenbelow based on the information inTables II–12 and II–13. The followingdiscussion is structured similar to thatfor the 1-hour nonattainment analysis inthat results are presented for the‘‘violating county’’ approach andsupplemented with results from the ‘‘allgrid-cell’’ approach.

Subregion 1 (portions of Illinois,Wisconsin, Indiana, and Iowa):emissions in this subregion contributeover 25 ppb to nonattainment inMichigan with contributions of 5 to 10ppb in Ohio as well as contributions of2 to 5 ppb to six other States.

Subregion 2 (portions of Michigan,Indiana, and Ohio): emissions in thissubregion contribute 2 to 5 ppb to 16States as far downwind as NewHampshire and Maine withcontributions of 5 to 10 ppb or more infive States.

Subregion 3 (portions ofPennsylvania, New York and Delaware):emissions in this subregion contribute10 to 15 ppb to three States along theNortheast Corridor with contributions of5 to 10 ppb in Massachusetts and NewHampshire.

Subregion 4 (New Jersey, Connecticutand portions of New York, Pennsylvaniaand Delaware): emissions from thissubregion contribute over 25 ppb toRhode Island and Massachusetts withcontributions of 15 to 20 ppb in Maine.

Subregion 5 (portions of Illinois,Indiana, Kentucky, Missouri, andTennessee): emissions from thissubregion contribute 2 ppb or more to13 States with contributions of 10 to 15ppb in two States.

Subregion 6 (portions of Ohio,Indiana, Kentucky, Tennessee, WestVirginia and Virginia): emissions in thissubregion contribute 5 to 10 ppb ormore to 10 States with contributions of15 ppb or more in two States.

Subregion 7 (Maryland, Washington,DC, and portions of Delaware, NorthCarolina, Virginia and West Virginia):emissions in this subregion contribute10 to 15 ppb or more to four States withcontributions of 5 to 10 ppb as fardownwind as Rhode Island andMassachusetts and 2 to 5 ppb in Maine.

Subregion 8 (portions of NorthCarolina, South Carolina and Georgia):emissions in this subregion contribute10 to 15 ppb to three States and 15 to20 ppb to one of these States; multiplecontributions of 2 to 5 ppb are predictedas far downwind as New Jersey.

Subregion 9 (portions of Tennessee,Georgia, Alabama, Mississippi, North


and South Carolina and Arkansas):emissions in this subregion contribute 5to 10 ppb to six States withcontributions of 10 to 15 ppb in twoStates.

Subregion 10 (Florida and portions ofMississippi, Alabama, Georgia andLouisiana): emissions in this subregioncontribute 2 to 5 ppb in two States and5 to 10 ppb in one State.

Subregion 11 (portions of Texas,Louisiana, Arkansas and Oklahoma):emissions in this subregion contribute 2to 5 ppb in six States.

Subregion 12 (portions of Missouri,Iowa, Wisconsin, Minnesota, NorthDakota, South Dakota, Nebraska, Kansasand Oklahoma): emissions in thissubregion contribute 2 to 5 ppb in threeStates; considering the ‘‘all grid-cell’’approach indicates multiplecontributions of 2 to 5 ppb downwindover Lake Michigan and Lake Erie.

The results indicate that thecontributions to 8-hour nonattainmentare very consistent with those for 1-hournonattainment. Subregions 1 through 9have a much greater magnitude,frequency, and geographic extent ofcontribution compared to the othersubregions. Thus, based on thisassessment, EPA believes that emissionsfrom subregions 1 through 9 make amarked contribution to downwindnonattainment for the 8-hour NAAQS.In fact, the extent of contributions frommost of these subregions (i.e., 1 through9) is even larger for 8-hournonattainment while the contributionfrom the other subregions (i.e., 10, 11,and 12) still remains relatively low bycomparison.

8. Assessment of State Contributions

The preceding air quality, trajectory,emissions, and modeling analysesprovide a number of pieces ofinformation for determining, based onthe weight of evidence, which Statesmake a significant contribution todownwind nonattainment. Theassessment of the State contributions isdivided into three parts. States whichare wholly or partially contained withinsubregions 1–9 are considered first sinceemissions from these States make amarked contribution to downwindnonattainment for both the 1-hour and8-hour NAAQS, based upon thesubregional modeling. States whichwere not included in any of the OTAGsubregions (i.e., some of the NewEngland States) are considered second.States located in subregions 10, 11 and12, which did not have a markedcontribution to downwindnonattainment for either the 1-hour or 8-hour NAAQS, are discussed last.

The subregional modeling resultsindicate that emissions from States insubregions 1 through 9 produce largedownwind contributions in terms of themagnitude, frequency, and geographicextent of the downwind impacts. Inaddition, nonattainment areas withinmany States in the OTAG region receivelarge and/or frequent contributions fromemissions in these subregions. The EPAbelieves that the following States whoseemissions are wholly or partiallycontained within one or more of thesesubregions (i.e., Alabama, Connecticut,Delaware, Washington DC, Georgia,Illinois, Indiana, Kentucky, Maryland,Michigan, Missouri, New Jersey, NewYork, North Carolina, Ohio,Pennsylvania, South Carolina,Tennessee, Virginia, West Virginia, andWisconsin) is making a significantcontribution to downwindnonattainment. In addition to themarked levels of contributionsdescribed above, this finding is basedon:

• OTAG strategy modeling and non-OTAG modeling indicates that NOX

emissions reductions across these Stateswould produce large reductions in 1-hour and 8-hour ozone concentrationsacross broad portions of the regionincluding 1-hour and 8-hournonattainment areas;

• The air quality, trajectory, and windvector analyses indicate that theseStates are upwind from nonattainmentareas within the 1- to 2-day distancescale of transport;

• These States form a contiguous areaof manmade emissions covering most ofthe core portion of the OTAG region;

• 11 of the States that are whollywithin these nine subregions (i.e.,Illinois, Indiana, Kentucky, New Jersey,North Carolina, Ohio, Pennsylvania,South Carolina, Tennessee, Virginia andWest Virginia) have a relatively highlevel of NOX emissions from sources intheir States; these States are ranked inthe top 50 percent of all States in theregion in terms of total NOX emissionsand/or have NOX emissions exceeding1000 tons per day, as indicated in TableII–1;

• States wholly within subregions 1through 9 with lesser emissions (i.e.,Connecticut, Delaware, Maryland) andWashington, DC have a relatively highdensity of NOX emissions, as indicatedin Table II–2;

• For the nine States that are onlypartially contained in one of subregions1 through 9 (i.e., Arkansas, Iowa,Michigan, Mississippi, Missouri,Alabama, Georgia, Wisconsin, and NewYork) the State total NOX emissions inTable II–1 as well as each State’scontribution to NOX emissions in the

subregions (see Tables II–14a and II–14b) indicate that six of these States(i.e., Michigan, Missouri, Alabama,Georgia, Wisconsin, and New York)each have: NOX emissions that aregenerally more than 10 percent of thetotal NOX emissions in one of thesesubregions, and either NOX emissions inthe top 50 percent among all States,and/or a majority of the State’s NOX

emissions are within one of thesesubregions.

For the New England States that werenot included in any of the OTAG zero-out subregions (i.e., Maine,Massachusetts, New Hampshire, RhodeIsland, and Vermont), State emissionsdata indicate that both Massachusettsand Rhode Island have a high density ofNOX emissions (see Table II–2). Also,the trajectory and wind vector analysesindicate that these States areimmediately upwind of nonattainmentareas in Maine and New Hampshire.Thus, EPA believes that these two States(i.e., Massachusetts and Rhode Island)also make a significant contribution todownwind nonattainment for both the1-hour and 8-hour NAAQS.

In summary, based on the weight ofevidence, EPA believes that the 22States plus the District of Columbia’sconsolidated metropolitan statisticalarea which make a significantcontribution to downwindnonattainment for both the 1-hour and8-hour NAAQS are:Alabama,Connecticut,Delaware,District of Columbia,Georgia,Illinois,Indiana,Kentucky,Maryland,Massachusetts,Michigan,Missouri,New Jersey,New York,North Carolina,Ohio,Pennsylvania,Rhode Island,South Carolina,Tennessee,Virginia,West Virginia,Wisconsin.

It should be noted that under EPA’salternative interpretation of section110(a)(2)(D), these areas would bedetermined to significantly contribute tononattainment problems downwindonly after consideration of additionalfactors, including the respective costs ofcontrols on emissions in upwind and


7 32 percent is the median effectiveness of theRCS considering all nonattainment areas in theOTAG region.

downwind areas, to the extent thisinformation is at least qualitativelyavailable. Those additional factors,discussed in section II.D. below, leadsEPA to propose to conclude that theseareas contribute significantly under thisinterpretation as well.

For the nine States in the OTAGregion which are wholly withinsubregions 10, 11, and 12 (i.e., Florida,Kansas, Louisiana, Minnesota,Nebraska, North Dakota, Oklahoma,South Dakota, and Texas), the OTAGand non-OTAG modeling informationindicates that emissions from theseStates make at most a relatively smallcontribution to downwindnonattainment. Also, most of theseStates are relatively distant from manyof the downwind nonattainment areasin the OTAG region and have arelatively low amount of manmade NOX

emissions and/or NOX emissionsdensity. Thus, as discussed in sectionVI, States Not Covered By ThisRulemaking, the weight of evidenceavailable does not support a finding thatthese States make a significantcontribution to downwindnonattainment.

D. Comparison of Upwind andDownwind Contributions toNonattainment and Costs of Controls

Important parts of EPA’sdetermination of whether, and to whatextent, to require controls on upwindNOX emissions that are linked toregional transport are comparing thecontribution to downwindnonattainment problems of upwindNOX emissions as opposed to local,downwind NOX or VOC emissions; aswell as comparing the costs of achievingdownwind ozone reductions throughupwind emissions reductions, asopposed to through downwindemissions reductions. Depending on theinterpretation for section 110(a)(2)(D),the relative downwind contribution andthe respective costs are either a factor inthe determination of what emissionslimitations constitute adequatemitigation of that contribution, or theyare a factor in the significantcontribution test.

Under the CAA requirements,downwind nonattainment areas arealready obligated to implementsignificant controls. The provisions forclassified areas mandate cascadingcontrol requirements so that higherclassified areas must implement thesame controls as lower classified areas,plus additional controls. Thesemandated controls generally areassumed in the OTAG/EPA modelingfor the 2007 base case, as describedabove. These mandated controls may be

viewed as the first increment of requiredcontrols that will bring thenonattainment areas into attainment.Today’s proposal indicates that the nextincrement of controls should be theregional controls, for the reasonsdescribed below.

The EPA has developed preliminarydata indicating that regional NOX

emissions reductions in the OTAGregion are a cost-effective means forreducing ozone levels in nonattainmentareas downwind, compared to the costsof further reductions in local VOC andNOX emissions in those nonattainmentareas. The EPA developed thisinformation based on data from therecent regulatory impact analysis (RIA)for the new ozone standard. The EPAestimated the amount of VOC and/orNOX emissions reductions which wouldbe needed for areas to attain the newstandard as well as the air qualityimprovement resulting from a regionalNOX strategy. The EPA then comparedthe potential cost of achievingattainment through a strictly localemission reduction approach alone tothe cost of a regional NOX strategy.

The preliminary cost comparison wasbased on a simplified analysis thatillustrates the potential control costdifference between a regionally-coordinated NOX strategy and acollection of local control strategies inprojected ozone nonattainment areas.The analysis estimates that the existenceof a 22-States and the District ofColumbia (‘‘23 jurisdiction’’) regionalNOX strategy has the potential to avoidfrom $2.9 to $12.8 billion dollars of thetotal annual cost that would be incurredunder the alternative local controlstrategy. This ‘‘cost avoided’’ can becompared to the estimated annual costof $2.8 billion for the regional NOX

strategy assumed in the RIA to evaluatethe relative efficiency of a regionalstrategy.

The EPA’s analysis is based on tworuns of the ROM. The first run, calledthe local control strategy (LCS) run,estimates ozone air quality based on a2007 emissions projection assumingCAA-mandated controls, but notincluding a regional NOX strategy. Thesecond run, called the regional controlstrategy (RCS) run, estimates ozone airquality based on a 2007 emissionsprojection with a regional NOX strategy.This strategy includes a regionwideemissions cap based on a 0.15 lb/MMBtu NOX limit on utilities and largeindustrial boilers, and the National LowEmission Vehicle (NLEV) program.While not identical to the regionalcontrol assumptions in this rulemaking,the RCS run is similar enough to offerinsights for this cost comparison.

Using the LCS ROM runs, EPAestimated the potential local NOX and/or VOC emission reductions needed in17 projected ozone nonattainment areasto attain the new 8-hour ozone standard.An additional 13 areas are alsoprojected to be nonattainment under theLCS scenario, but emission reductiontargets were not established for theseareas. These additional areas are notincluded in this analysis; thus, theestimates presented in this analysis ofthe potential local control cost avoideddue to the regional NOX strategy arelikely underestimated.

Based on the ROM run for the RCSscenario, EPA estimated the effect of theregional NOX strategy on future ozoneconcentrations for the 17 areas. Seven ofthese 17 areas are projected to attain thenew ozone standard as a result ofcontrols in the RCS scenario. These 7areas are given a 2007 RCS reductiontarget credit of 100 percent (i.e., furtherlocal reductions may not be needed forattainment). For the 10 remainingnonattainment areas, the RCS isestimated to be 32 percent effective 7

toward achieving the air qualityattainment target relative to the LCS.This is based on a comparison of ROMpredictions for the LCS and RCSscenarios versus the air quality target(0.08 ppm/8-hour/4th max ozonestandard). Therefore, all remaining areasare given a 32 percent credit towardtheir respective VOC and/or NOX

emission reduction targets. For theregional NOX strategy, the total avoidedlocal VOC reductions are over 513,000tons, and the total avoided local NOX

reductions are nearly 767,000 tons. Thisanalysis indicates that the regional NOX

emissions reductions provide equivalentair quality benefits to a large portion ofthe local VOC and/or NOX emissionsreductions which may be needed toattain in these areas. This findingweighs in favor of concluding that theregional NOX reductions are appropriateto mitigate the upwind contribution or,under the second interpretation ofsection 110(a)(2)(D), that the relevantupwind areas significantly contribute tononattainment problems downwind.

As discussed in the next section, EPAhas identified a set of regional NOX

controls in a cost range of $1,650 to$1,700 per ton. These regional upwindand downwind control costs appear tocompare favorably to the potentialcontrol costs associated with thedownwind local controls, as indicatedin Table II–15. The avoided cost of localVOC control is assumed to range from


a low-end cost of $2,400 per ton to ahigh-end cost of $10,000 per ton. Theavoided cost of local NOX control isassumed to range from a low-end cost of$2,200 per ton to a high-end cost of$10,000 per ton. The low-end costs arederived from the nationwide averageincremental costs of VOC- and NOX-related control measures selected in theRIA for the new ozone standard. Thehigh-end cost of $10,000 per ton isassumed based on the PresidentialDirective for the Administrator of EPAregarding ‘‘Implementation of RevisedAir Quality Standards for Ozone andParticulate Matter’’ issued by PresidentClinton.

The foregoing analysis suggests, atleast directionally, that the regionalNOX reductions that would result fromtoday’s proposal may have the sameambient impact, but at lower cost, thanavailable local VOC and NOX

reductions. Thus, this analysis isanother factor supporting EPA’sproposed conclusion that the SIPs forStates in this region are required, undersection 110(a)(2)(D), to reduce NOX

emissions.

III. Statewide Emissions Budgets

A. General Approach for CalculatingBudgets

This section describes the generalapproach EPA is proposing to use todevelop emission budgets under today’saction and the rationale for thatapproach. In addition to a description ofhow control measures were selected,this section addresses other issuesrelated to calculating budgets,including: relationship to OTAGrecommendations, uniform applicationof controls, seasonal versus annualcontrols, and treatment of areas withNOX waivers.

1. Overview

In earlier parts of today’s action, EPAproposed to determine that NOX

emissions from 23 jurisdictionscontribute significantly tononattainment problems in downwindareas in the OTAG region. In this andsubsequent parts, EPA proposes torequire a NOX budget for each of thesejurisdictions for those emissions thatwill result in sufficient reductions toadequately mitigate the contribution.The EPA proposes as the criteria forestablishing the budget the relative costeffectiveness of the emissionsreductions associated with the availablecontrols, combined with reference to theambient impact of the emissionsreductions. The EPA solicits commenton alternative approaches forestablishing State emissions budgets

that factor in the differential effects ofNOX reductions in different geographiclocations on downwind air quality.

Specifically, for the proposedapproach, EPA employed the followingsteps in determining the budget levelsthat EPA proposes constitute adequatemitigation under the first interpretationof significant contribution. First, EPAcompiled a list of available NOX controlmeasures for the various emissionssectors in the upwind areas. For thecontrol measures on this list, EPAestimated the average cost effectivenessof those controls. The average costeffectiveness is defined as the cost of aton of reductions from the sourcecategory based on full implementationof the proposed controls, as compared tothe pre-existing level of controls.

Second, EPA developed a rationale fordetermining which of the NOX controlmeasures should form the basis of thebudget. The EPA focused on averagecost effectiveness of the controls. As apoint of comparison, EPA determinedthe average cost effectiveness of arepresentative sample of recent currentand planned State and Federal controls.The EPA believes that the average costeffectiveness for the measures proposedtoday to form the basis for the budgetsshould be comparable to the averagecost effectiveness of those recentlyundertaken and planned controls.

Third, EPA evaluated controlmeasures to determine whether theyshould be assumed in the budgetcalculation based on this rationale. TheEPA proposes that when controls onutilities in the 23 jurisdictions areextended to the level proposed today,and when controls on nonutility pointsources are similarly extended, then theaverage cost effectiveness of the utilitycontrols and of the nonutility pointsource controls are both comparable tothe average cost effectiveness of recentlyundertaken and planned controls.

At the same time, EPA analyzed theaverage cost effectiveness for NOX

reductions from source categories otherthan utilities or other point sources. TheEPA is today proposing that additionalcontrols (beyond the current andplanned measures described in sectionIII.B.2.b) from those categories shouldnot form the basis for any of the budgetsbecause their costs, for the purpose ofreducing only NOX emissions, aresignificantly higher than those of theutilities and other point sources and/oradditional feasible controls have eithernot been identified or are moreappropriate for local, not regional,implementation.

Fourth, EPA determined the state-by-state budgets for NOX emissions basedon the selected controls.

Fifth, EPA determined that thesebudget levels—or generally comparablelevels—result in an adequate level ofambient reductions downwind. TheEPA did not conduct ambient air qualitymodeling for the level of emissionscontained in the budgets proposedtoday. However, OTAG conducted airquality modeling for a set of controlsthat, although somewhat different fromthe utility and point source controlsEPA is today proposing to rely on,yielded comparable emission levels, ona regionwide basis, to those proposedtoday. This modeling indicated anoticeable improvement in ozoneconcentrations due to implementationof the required emissions budget. TheAgency intends to include air qualityanalyses of the proposed NOX emissionsbudgets in the SNPR. Although EPA isproposing that States be required toachieve the emissions budgets specifiedand has based those budgets on aparticular set of cost-effective controls,States may select their own mix ofcontrols that meet this budget.

Sixth, EPA determined that, based oncurrent information, requiring upwindNOX emissions reductions, based on anassessment of their costs and ambientimpact, is more appropriate thanrequiring downwind VOC emissionsreductions, based on an assessment oftheir costs and ambient impacts. TheEPA’s current information is limited forthis aspect of today’s rulemaking, butgenerally consists of the analysesperformed for the RIA for the revisedozone and particulate matter NAAQS.

The alternative interpretation forsection 110(a)(2)(D) of the CAA, whichEPA is also proposing today, shouldalso be noted. Under this interpretation,the various factors included in theweight of evidence approach discussedabove concerning the upwind emissionsand ambient contributions, therefore,would be part of the determination as towhether the emissions contributesignificantly to nonattainment problems(or interfere with maintenancedownwind). The EPA would thenundertake the same cost analysis asdescribed above as an additional factorin the weight of evidence test. If EPAconcluded that the regional NOX

emissions controls are appropriatelycost effective, EPA would conclude, onthe basis of all the factors, that theemissions subject to those controls areconsidered to contribute significantly tononattainment. Under thisinterpretation of section 110(a)(2)(D),the State budget levels, which are basedon the cost-effective control measures,are necessary to prohibit the amount ofthe State’s emissions determined to


contribute significantly tononattainment.

2. Relationship of Proposed BudgetApproach to the OTAGRecommendations

In selecting those control measuresdetermined to be the most reasonableand cost effective for the purpose ofachieving regional NOX reductions, EPAcarefully considered therecommendations made by OTAG onJuly 8, 1997 (Appendix B). The OTAGprocess is described in section I.F,OTAG Process, of this rulemaking. Thecontrol measures assumed in theproposed budget calculations describedbelow generally fall within the range ofOTAG’s recommendations.

The OTAG recommendations call forimplementation of several Federalmeasures to achieve NOX emissionsdecreases through a NLEV program,inspection and maintenance (I/M)programs (where required by the CAA),and reformulated gasoline (RFG) inmandated and current opt-in areas.Emissions reductions following theserecommendations are included in EPA’scalculation of the highway vehiclebudget component as part of the 2007Clean Air Act base.

The OTAG recommendations endorsethe development and implementation ofozone action-day programs. Therecommendations also encourage EPAto evaluate emission benefits of cetaneadjustments with respect to diesel fuel.While EPA supports theserecommendations, it should be notedthat they do not translate into specificemissions reductions at this time and,thus, EPA did not calculate emissionsreductions from these programs as partof the proposed budget calculation.

The OTAG recommendations alsocover electric utilities and other large-and medium-sized point sources.Specifically, OTAG recommendedcontrols discussed below in all of the‘‘fine grid’’ areas. The OTAGrecommended that emissions fromsources in the portion of States that arein the ‘‘coarse grid’’ be exempted fromthe budget calculation. The EPA isproposing to include entire States ratherthan exempting portions based on thedivision between coarse and fine grid.This affects New York, Michigan,Wisconsin, Missouri, Alabama andGeorgia. The EPA proposes to take thisapproach because the division betweenfine and coarse grid areas was based, inpart, on technical modeling limitations;because the additional emissionsdecreases will help the downwindnonattainment areas; and because astatewide budget creates feweradministrative difficulties than a partial-

state budget. The OTAG fine grid Statesare the same as the 23 jurisdictionsproposed in this rulemaking as havinga significant contribution, with theexception of the States of Maine, NewHampshire and Vermont. The portion ofthese three States in the OTAG fine gridare included in the OTAGrecommendation for additional controls,but are not included in today’s proposalfor the reasons described in section II,Weight of Evidence Determination ofSignificant Contribution, of thisrulemaking. The EPA is solicitingcomments on this approach;specifically, whether partial Statesshould be included, which States orparts of States should be excluded, theappropriate rationale for excludingStates or parts of States, and how toaddress administrative difficultiesassociated with excluding parts of aState.

For electric utilities, OTAGrecommended that the range of utilityNOX controls in the fine grid fallbetween CAA controls (about a 30percent reduction from 1990 levels) andthe less stringent of 85 percentreduction from the 1990 rate or 0.15 lb/MMBtu. As discussed below, EPA’sproposed utility budget componentcalculation is based on the 0.15 lb/MMBtu emission rate without the 85percent reduction option. Thus, EPA’sproposed utility budget componentcalculation is similar to the upperbound recommended by OTAG, butwith a slightly lower overall emissionrate (since it excludes the 85 percentreduction criterion) and slightlydifferent total area (since whole States—not just the fine grid portion—but fewerStates are included). The alternativesconsidered and explanation of themethodology proposed to make thesecalculations are more fully discussedbelow and in the technical supportdocument (TSD) which is included inthe Docket to this rulemaking.

For nonutility point sources, OTAGrecommended that the stringency ofcontrols for large sources be establishedin a manner equitable with utilitycontrols. The OTAG recommendationincludes a definition of large sources(e.g., industrial boilers with a heat inputgreater than 250 MMBtu) andrecommends control levels ranging from55–70 percent reduction. The OTAGPolicy Group further recommended thatRACT should be considered forindividual medium-sized nonutilitypoint sources (e.g., industrial boilerswith a heat input between 100 and 250MMBtu). The EPA-proposed nonutilitybudget component calculationsgenerally follow the OTAGrecommendations. Missing data in the

OTAG emissions inventories, however,preclude EPA from precisely followingthe recommended definitions of large-and medium-sized sources. Thealternatives considered and explanationof the methodology proposed to makethese calculations are more fullydiscussed below.

3. Uniform Application of ControlMeasures

The EPA is proposing that the budgetfor each State that has been determinedto contribute significantly tononattainment in a downwind State becalculated using the same controlmeasure assumptions. This is true undereither interpretation, described above, ofsection 110(a)(2)(D). An alternativeapproach would be for EPA to attemptto identify for each State or a group ofadjacent States (e.g., Ohio Valley, GreatLakes, Southern, or Northeastern States)a unique set of control levels on whichto base emissions budgets that, togetherwith other States’ emission budgets,would eliminate significant contributionto downwind nonattainment areas. TheEPA is soliciting comment onmethodologies that might be used toimplement such an approach. Thedecision to propose to calculate budgetsbased on uniform control measures isbased primarily on cost effectiveness(cost per ton removed) and also inconsideration of the OTAGrecommendations, collectivecontribution, equity concerns, modelingassumptions and concerns overemissions shifting. These are discussedfurther below.

a. OTAG. Although OTAG did notethat the range of transport is generallylonger in the North than in the South,the OTAG recommendations did notspecifically indicate whether controlsshould be applied at differing levelsover the fine grid.

b. Collective Contribution and EquityConsiderations. The EPA believes thatcertain downwind States receiveamounts of transported ozone and ozoneprecursors that significantly contributeto their nonattainment. The EPA furtherbelieves that it is the ‘‘collective’’emissions of ‘‘several’’ upwind Statesthat result in significant contributions.All States included within a group ofStates whose collective emissionssignificantly contribute tononattainment may be assumed tocontribute significantly. Because eachState’s contribution is viewed withreference to other States’ contributions,EPA believes it is appropriate to requirethe same type of remedial action foreach State.

The proposed approach results in thecalculation of statewide emissions


budgets based on the consistentapplication of potential controls acrossthe States determined to contributesignificantly. This approach treats the23 jurisdictions in a like manner for thepurpose of calculating the proposedstatewide emissions budgets.

c. Modeling Assumptions andPotential Synergistic Effects. In theory,it would be possible to derive moreprecise contributions made byindividual States to collective transportof ozone and precursors to downwindStates. In practice, however, this is amore challenging analysis. First, therelative impact of individual States,within a collective group of States, ontransport varies as a function ofmeteorology. For example, the impact ofmore distant States may be relativelygreater when there is a well definedwindfield. In contrast, effects of nearbyStates may be most pronounced understagnant or semi-stagnant conditions.Modeling may therefore not sufficientlycharacterize the relative importance ofemissions in individual States toregional transport, unless many daysreflecting a variety of meteorologicalconditions are modeled.

Second, the impact of an individualState on downwind transport of ozoneand precursors depends on what isassumed about emissions in other Statesin the collective group shown to resultin significant transport. This isexacerbated by the fact that ozoneformation and transport is not a linearfunction of precursor emissions. Rather,there is likely to be a synergistic effectwhich arises from reducing emissions inseveral neighboring States. Thus, thepredicted relative importance ofemissions from a single State mightchange substantially if emissions fromother States in the group were reduced.There is a myriad of assumptions whichcan be made about emission controls inneighboring States. It is not feasible tomodel them all. Thus, a definitive,precise estimate of the relativeimportance of a single State’scontribution to transport is unlikely. Onthe other hand, OTAG has performedmodeling showing the air qualityimpacts of applying differential levels ofcontrols in different zones of the OTAGdomain (see section II.B.3, OTAGGeographic Modeling). In sectionIII.A.3.e below, EPA is requestingcomment on the possibility of using thisor some other analysis as a means forconsidering an alternative approach todeveloping NOX budgets.

d. Electrical Generation andEmissions Shifting. Among many factorsthat EPA considered in weighingwhether to propose uniform or variableemissions limits in calculating States’

emission budgets was the concern thatdifferent controls in one part of theOTAG fine grid region in combinationwith an interstate emissions tradingprogram may lead to increases inpollution within areas having morerestrictive controls. That is, ifunrestricted interstate emissions tradingwere allowed, emissions reductionsmight be expected to shift away fromStates assigned more restrictive controlsto States which received less restrictivecontrol requirements due to the lowercontrol costs likely to exist in Stateswith less restrictive controls. This mayresult in emissions above the budgetlevel in areas with more restrictivecontrols. Such shifts are an importantconcern and may be most significant forlarge combustion sources because theyemit a large portion of the total regionalNOX emissions and dominate pointsource emissions.

On the other hand, having theinterstate trading program incorporatecontrol levels that vary from State toState by varying the value of anemission credit or allowance wouldcomplicate administration of the tradingprogram. Such complexity wouldincrease transaction costs and coulddiscourage emissions trading whichmay result in higher regionwide controlcosts. Alternatively, the scope of thetrading program could be confined tothose States with similar control levels.However, each subregional tradingprogram would have fewer participants.A trading program that covers a smallermarket area will provide less flexibilityand reduce the possible savings for theaffected sources as compared with largertrading programs.

e. Alternative Approaches Based onNon-Uniform Application of ControlMeasures. The EPA is proposing toderive State NOX emissions budgetsusing uniform control measures. Asdiscussed earlier in this section, EPAbelieves it is appropriate to requirecomparable levels of control of NOX

emissions throughout the 23jurisdictions covered by today’s action.The EPA selected these proposed levelsprimarily by considering the costeffectiveness of control at the source(i.e., the control cost per ton of NOX

reduced for each type of source).Although not all such emissionsreductions are equally effective inreducing ozone concentrations in targetnonattainment areas, EPA believes thatother benefits of NOX reductions andequity considerations are also importantand support this type of approach.

In a July 1997 Memorandum to theEPA Administrator, the Presidentdirected the Agency to maximizecommon sense, flexibility, and cost

effectiveness in implementing therevised ozone and particulate matterstandards. Fulfilling this mandate bydeveloping the least burdensomestrategy for achieving air qualityimprovements, and ultimatelyattainment in nonattainment areas,requires technically complex analysis ofregional transport, similar to thatundertaken as part of the OTAG process.As noted elsewhere in this package, anumber of other factors, includingdistance and meteorology, influencehow effective different tons of emissionsreductions are in reducing ambientozone concentrations in nonattainmentareas.

The EPA recognizes that analyticapproaches other than one based onusing uniform control measures mightbe useful in deriving State NOX

emissions budgets. For example, oneapproach would be to attempt toquantify more explicitly the costeffectiveness in terms of the ambientozone improvement in nonattainmentareas (measured, for example, as costper population weighted changes inparts per billion of peak ozoneconcentrations) taking into account thelocation of control measures throughregional modeling. This alternative, iffeasible, would clarify the linkagebetween the budget calculation andambient ozone improvement innonattainment areas and, depending onits effect on interstate emissions trading,could thereby lower the overall cost ofachieving comparable ambient ozoneimprovements in nonattainment areas.Alternative approaches to measuringcost effectiveness that would moredirectly link cost effectiveness toimprovements of air quality innonattainment areas could also beadopted.

The EPA solicits comment onalternative approaches for establishingState emissions budgets that factor inthe differential effects of NOX

reductions in different geographiclocations on downwind air quality.Comments advocating alternativeapproaches would be most helpful ifthey set forth concrete proposals onwhat analysis should form the basis forbudget calculations. The EPA plans toreview alternative approaches andperform additional air quality andeconomic analysis in developing thefinal rule. If, after review of alternativeapproaches, EPA concludes that a newbasis for the State emissions budgets isappropriate, EPA would issue a SNPR.

4. Seasonal vs Annual ControlsToday’s proposal is for the purpose of

helping attain and maintain the NAAQSfor ozone. High ambient concentrations


of ozone are associated with periods ofelevated temperature and solarradiation. Thus, in most parts of thecountry, high ozone episodes occur onlyduring summer months. Accordingly,the control of NOX emissions primarilyon a summer season basis may be partof some areas’ strategies to attain theozone standard at least cost. The OTAGanalyses have assumed that the controlrequirements flowing from this processwould be required only over the ozoneseason, which OTAG considered to beMay 1 through September 30. For thepurpose of decreasing the regionaltransport of ozone and ozoneprecursors, EPA agrees that controlmeasures that focus over the ozoneseason may be appropriate and isproposing seasonal NOX budgets.

Because NOX emissions have adverseimpacts on the environment in severalways (as described in section IX.,Nonozone Benefits of NOX Reductions),it should be noted that the timing of theNOX emissions can be important to thesubsequent environmental impacts. Forexample, year-round reductions in NOX

emissions are more helpful thanseasonal approaches at minimizing theimpacts of acid deposition andeutrophication, although summertimeNOX emissions reductions are mosthelpful in attaining the ozone standard.Application of NOX emissions controlsthat focus emissions reductions in thesummer will, in many cases, alsoachieve significant emission reductionson a year-round basis. For example,efforts to decrease emissions from largeboilers will usually include installationof low NOX burners—which willachieve year-round moderate amountsof emission reductions—and mayinclude, in addition, some type ofsummer season control, such asswitching to a cleaner fuel or post-combustion technology. Therefore,while the purpose of this rulemaking isto address ozone transport thatsignificantly contributes to downwindnonattainment, which is primarily aconcern during the ozone season, Statesmay wish to consider the totalenvironmental impacts when adoptingmeasures to achieve the NOX emissionsdecreases.

The OTAG modeling used emissionsinventory information that representedtypical summer day emissions. In thisrulemaking, EPA is proposing seasonalemission budgets for each of the 23affected jurisdictions. Thus, indeveloping the budget, a conversion isneeded to arrive at a seasonal budget. Asin the OTAG process, EPA is proposingto use May 1 through September 30 asthe ozone season. The detailedprocedures for converting the daily

emissions into the seasonal budgets aredescribed below for each source sector.The proposed budgets are in units oftons of anthropogenic NOX for theseason May 1 to September 30. SinceStates will generally only be able toaffect anthropogenic sources, theproposed budget does not includebiogenic or geogenic sources.

5. Consideration of Areas With CAASection 182(f) NOX Waivers

The OTAG process included lengthydiscussions on the potential increase inlocal ozone concentrations in someurban areas that might be associatedwith a decrease in local NOX emissions.The OTAG modeling results indicatethat urban NOX emissions decreasesproduce increases in ozoneconcentrations locally, but themagnitude, time, and location of theseincreases generally do not cause orcontribute to high ozone concentrations.That is, NOX reductions can producelocalized, transient increases in ozone(mostly due to low-level, urban NOX

reductions) in some areas on some days,but most increases occur on days and inareas where ozone is low. The OTAGrecommended that the States worktogether and with EPA towardcompleting local SIPs, includingevaluation of possible local NOX

disbenefits. The EPA agrees that furtheranalysis of this effect is needed as partof the development of local attainmentplans. With respect to regional ozonetransport and today’s proposed action,EPA believes it is not appropriate togive special treatment to areas with NOX

waivers as discussed below.In calculating the proposed statewide

NOX emissions budget, EPA consideredthe options of: (1) requiring lessreductions from a State that had beengranted a NOX waiver under section182(f) of the CAA, or (2) ignoring theNOX waiver for purposes of calculatingthe transport budget. As describedbelow, EPA believes it is inappropriateto give special treatment to areas withNOX waivers when consideringmeasures to reduce the regionaltransport of ozone and ozoneprecursors. Therefore, EPA is proposingto calculate the statewide emissionsbudget without special consideration forareas with NOX waivers. The EPA viewsthe effect of NOX waivers on air qualityas appropriate for further analysis byeach State as part of its local attainmentplanning process, and EPA willconsider such results when workingwith each State’s attainment plan.

In option (1), the upwind States withNOX waivers would achieve only aportion of the emissions decreasesotherwise required under the statewide

emissions budget. Thus, the downwindnonattainment areas would receive lessimprovement in air quality and wouldneed to adopt additional controlmeasures in their States. To some degreethis approach defeats the purpose oftoday’s action because fewer emissionsreductions in the upwind areas wouldlead to higher ozone concentrations inthe downwind areas.

In option (2), the upwind States maybe able to achieve the NOX emissionsdecreases needed to meet their budgetsin those portions of the State whereNOX emissions decreases are not aproblem. On the other hand, the Statemay need to implement some NOX

emissions decreases in areas where suchdecreases may lead to increases inozone concentrations on some days.Thus, additional VOC control measuresmay be needed to offset associatedozone increases due to NOX emissionsdecreases in the sensitive areas. Thisapproach is more consistent with thepurpose of today’s action and may ormay not result in additional VOCcontrols being needed.

In proposing option (2), it is helpfulto look more closely at why the NOX

waivers were initially granted and themanner in which they were granted.Most of the NOX waivers granted werenot supported by local or regional scaleair quality modeling analyses indicatingthat NOX emissions decreases wouldresult in ozone increases. In fact, mostof the waivers were granted based solelyon local air quality data indicating theareas were already attaining the ozonestandard. Thus, technical support foroption (1) is substantially incomplete. Inaddition, relevant modeling analysescompleted by OTAG and othersregarding the issue of NOX waiver areasneed to be considered as describedbelow.

The CAA requires EPA to view NOX

waivers in a narrow manner. In general,section 182(f) provides that waiversmust be granted if states show thatreducing NOX within a nonattainmentarea would not contribute to attainmentof the ozone NAAQS within the samenonattainment area. Only the role oflocal NOX emissions on local attainmentof the ozone standard is considered innonattainment areas outside an ozonetransport region. The role of NOX inregional attainment is addressedseparately under section 110(a)(2)(D) ofthe Act, which prohibits one State fromsignificantly polluting another State’sdownwind areas.

In response to State NOX waiverpetitions submitted between 1992–1995,EPA granted NOX waivers under section182. Most waivers were granted on thebasis that the area had already attained


the ozone standard and, thus, additionalNOX (or VOC) reductions ‘‘would notcontribute to ozone attainment in thearea.’’ In some cases, the waivers weregranted based on dispersion modelingwhich showed that the area wouldattain just as expeditiously based solelyon additional VOC reductions or thatlocal NOX reductions increased localpeak ozone concentrations; this alsomeets the above test that additional NOX

reductions would not contribute toozone attainment in the area.

Specifically, the EPA receivedpetitions for a NOX waiver for 51 ozonenonattainment areas. Of these petitions,EPA has approved waivers for 48nonattainment areas and 3 are pending.Most of the waivers granted (28 of 48)were simply based on air qualitymonitoring data over a period of 3 ormore years indicating the area hadattained the ozone standard (and, thus,additional NOX reductions were notneeded for attainment). Several Statessubmitted NOX waiver petitions (7 of48) accompanied by an attainment planshowing achievement of the ozonestandard by the statutory deadlinethrough additional VOC controls only.None of these 35 nonattainment areaswith approved NOX waivers havedemonstrated or even sought todemonstrate that NOX reductions mightincrease ozone concentrations inspecific areas. Only in the cases of theLake Michigan (9 nonattainment areas),Phoenix AZ, Baton Rouge LA and theHouston/Beaumont TX areas wasinformation submitted to show that, insome episodes, NOX emissionsdecreases lead to increases in peakozone concentrations (13 of 48). Thus,the technical support for option (1) issubstantially incomplete. Even for thefew areas which had modelinginformation, those analyses weregenerally considered preliminaryanalyses that would be replaced withmore complete modeling associatedwith attainment plans.

In the Federal Register noticesapproving individual waiver petitions,EPA gave notice that approval of thelocal petition, under section 182(f) ofthe CAA, is on a contingent ortemporary basis because subsequentmodeling or monitoring data for an areamay show attainment benefits from NOX

reductions, and stated that additionallocal and regional NOX emissionsreductions may be needed to reduce thelong range transport of ozone. Wheresuch additional NOX reductions arenecessary to reduce the long rangetransport of ozone, EPA stated thatauthority provided under section110(a)(2)(D) of the CAA would be usedand that a section 182(f) NOX waiver

would, in effect, be superseded for thosecontrol requirements needed to meet thesection 110(a)(2)(D) action. Further, EPAnoted that States may require additionalNOX reductions in these nonattainmentareas for nonozone purposes, such asattainment of the PM–10 standard orachieving acid rain reduction goals.

The OTAG addressed the complexissue of regional impacts due totransport of NOX and VOC emissions.The OTAG modeling results indicatethat urban NOX reductions producewidespread decreases in ozoneconcentrations on high ozone days. Inaddition, urban NOX reductions alsoproduce limited increases in ozoneconcentrations locally, but themagnitude, time, and location of theseincreases generally do not cause orcontribute to high ozone concentrations.Most urban ozone increases modeled inOTAG occur in areas already below theozone standard and, thus, in most cases,urban ozone increases resulting fromNOX reductions do not causeexceedance of the ozone standard. Thereare a few days in a few urban areaswhere NOX reductions are predicted toproduce ozone increases in portions ofan urban area with high ozoneconcentrations.

In other words, modeling analysesconducted as part of the OTAG processindicated that, in general, NOX

reduction disbenefits are inverselyrelated to ozone concentration. On thelow ozone days leading up to an ozoneepisode (and sometimes the last day orso), the increases are greatest, and onthe high ozone days, the increases areleast (or nonexistent); the ozoneincreases occur on days when ozone islow and the ozone decreases occur ondays when ozone is high. This indicatesthat, in most cases, urban ozoneincreases may not contribute toexceedances of the ozone standards.Overall, OTAG modeling thus suggeststhat the ozone reduction benefits of NOX

control may outweigh the disbenefits ofurban ozone increases in bothmagnitude of ozone reduction andgeographic scope.

It should be noted that the modelinganalyses completed within the OTAGprocess necessarily utilized a larger gridsize than States are likely to use in theirattainment plans. That is, futureanalyses by States will likely usesmaller grid sizes. The smaller grid sizesmay provide additional information oneffects such as local NOX emissionsreacting with local ozone. Theadditional information will beimportant as States develop theirattainment plans.

In summary, the EPA views ozonepollution as a regional problem as well

as a local problem. Thus, achievingozone attainment for an area, andthereby protecting its citizens fromozone-related health effects, oftendepends on the ozone and precursoremission levels of upwind areas. Inorder to achieve the needed upwindNOX emissions decreases, areas thatwere granted NOX waivers may need tocontrol NOX emissions for transportpurposes, even if the waivers remain inplace. Today’s action is part of theprocess that is leading to additionalNOX reductions requirements inattainment and nonattainment areasacross broad parts of the Nation toreduce interstate transport of ozone. Therequirements of today’s action applyboth to areas with approved NOX waiverpetitions and areas without suchpetitions. That is, any nonattainmentareas with NOX waiver petitionsapproved by EPA in the past or in thefuture are not proposed to be exemptfrom today’s action.

At the same time, EPA is sensitive tothe concerns of those areas (primarily inthe Lake Michigan area) that may berequired to achieve NOX reductions thatproduce local increases in ozoneconcentrations in order to reduceconcentrations in downwind areas. TheEPA is, thus, taking comments onapproaches that might be used toaddress such concerns on a case-by-casebasis. The EPA wishes to stress that itwould only consider an approach thattargets areas with concrete modelingresults documenting a likelihood oflocal disbenefits from NOX reductions atlocations and on days with high ozoneconcentrations. As already discussed,EPA does not believe adjustments toNOX budgets are appropriate for areaswith waivers based solely on theirability to attain the NAAQS withoutfurther reductions.

6. Relation of OTC NOX MOU toBudgets in the Ozone Transport SIPRulemaking

The 2007 Budgets for the electricutilities and the nonutilities weredeveloped independently of the OTCNOX MOU. The Ozone Transport SIPRulemaking allows States flexibility toachieve reductions from any sourcecategory; however, implementation ofthese requirements could becoordinated. The MOU covers largeboilers, both utility and nonutilityboilers. The Ozone Transport SIPRulemaking covers these sources as wellas other categories of major NOX

stationary sources. Although the OTCNOX MOU does not cover these othercategories, the OTC States regulatedemissions from these categories through


implementation of the RACT program,beginning in 1995.

The EPA believes thatimplementation of Phase II of the MOUshould proceed as scheduled, withachievement of the reductions by May1999. These emissions reductions areneeded to help reduce ozone transportand make progress toward attainment.Further, these reductions do not conflictwith the requirements imposed by theOzone Transport SIP Rulemakingbecause they do not exceed the requiredreductions. In Phase III of the MOU,however, the timing and the amount ofthe reductions required by the OTC’sMOU and RACT provisions are muchcloser to the timing and reductions fromthe Ozone Transport SIP Rulemaking.The emissions reductions required bythe Ozone Transport SIP Rulemakingare likely to be somewhat more stringentoverall than the OTC’s Phase IIIrequirements, and Phase IIIimplementation could occur about thesame time as the Ozone Transport SIPRulemaking reductions. Therefore, EPAintends to work with the OTC States tocoordinate Phase III implementationwith implementation of the emissionsreductions required by the OzoneTransport SIP Rulemaking.

The States in the OTC not covered bythe Ozone Transport SIP Rulemakingshould continue to develop, adopt andimplement Phases II and III of the MOU.Such reductions may be necessary toprovide for attainment of the ozoneNAAQS in those areas, although theymay not be significant with respect tolong distance transport. Further, suchreductions may help to attain and/ormaintain the new 8-hour ozonestandard.

B. Budget Development Process

1. Overview

The EPA is proposing to developseasonal budgets for each State bydetermining the amount of emissionsthat would remain in each State afterapplication of reasonable, cost-effectivecontrol measures. For all sectors exceptelectric utilities and nonutility pointsources, EPA proposes using the 2007Clean Air Act inventory developed byOTAG as the starting point for thiscalculation. This inventory reflectsimplementation of all mandatorynational and nonattainment area CleanAir Act controls, plus any additionalregional and State-specific controls. Italso includes growth assumptionsbetween 1990 and 2007. The specificassumptions on which this inventory isbased are documented in a June 1997draft Emissions Inventory DevelopmentReport (8). To determine the overall

State budgets, EPA proposes applyingcontrols to various source sectors, asdiscussed below, calculating budgetcomponents based on these controls,and summing the budget componentsfor each sector to get the total budget.

In the case of electric utilities, EPAproposes using a slightly differentapproach. Instead of using the OTAG2007 emissions and applying controls,EPA proposes to calculate the utilitycomponent of the budget using dataprovided by utilities to EPA for 1995and 1996 and increasing the emissionsto reflect activity growth projected for2007. This is discussed in more detailbelow in section III.B.3.

In the case of nonutility point sources,EPA proposes using the OTAG 2007emissions with one adjustment. Theinventory needs to be adjusted torepresent uncontrolled levels, ratherthan CAA control levels, because theOTAG recommendation is based onuncontrolled levels. This is discussed insection III.B.4, Proposed Assumptionsfor Area and Nonutility Point Sources.

2. Description of and Rationale forProposed Control Assumptions

An important issue to be addressed intoday’s action is the reasonableness ofthe cost of control of emissions in Statesthat significantly contribute to anotherState’s ozone nonattainment. The EPAproposes to address this issue byexamining the cost effectiveness ofvarious regionwide ozone seasoncontrol measures and determining whatmeasures can be considered the mostreasonable in light of other actions takenby EPA and States to control NOX.

a. Considering the Cost Effectivenessof Other Actions. The EPA is proposingto base the budget component levels onNOX emissions controls that areavailable and the most cost effective inrelation to other recently undertaken orplanned NOX measures. Table III–1provides a reference list of measuresthat EPA and States have undertaken toreduce NOX and their average annualcosts per ton of NOX reduced. Most ofthese measures fall in the $1,000 to$2,000 per ton range. With fewexceptions, the average costeffectiveness of these measures isrepresentative of the average costeffectiveness of the types of controlsEPA and States have needed to adoptmost recently, since their previousplanning efforts have already takenadvantage of opportunities for evencheaper controls. The measures listed inTable III–1 represent costs that theNation has been willing to bear to dateto reduce NOX. The EPA believes thatthe cost effectiveness of measures that itor States have adopted, or proposed to

adopt, forms a good reference point fordetermining which of the availableadditional NOX control measures canmost reasonably be implemented byupwind States that significantlycontribute to nonattainment.

TABLE III–1.—AVERAGE COST EFFEC-TIVENESS OF NOX Control Meas-ures Recently Undertaken

[In 1990 dollars]

Control measureCost per tonof NOX re-

moved

NOX RACT ................................ 150–1,300Phase II Reformulated Gasoline 1 3,400State Implementation of the

Ozone Transport Commis-sion Memorandum of Under-standing ................................. 950–1,600

Proposed New Source Perform-ance Standards for FossilSteam Electric GenerationUnits ...................................... 1,290

Proposed New Source Perform-ance Standards for IndustrialBoilers ................................... 1,790

1 Average cost representing the midpoint of$1,500 to $5,300 per ton. This cost representsthe projected additional cost of complying withthe Phase II RFG NOX standards, beyond thecost of complying with the other standards forPhase II RFG.

The Federal Phase II RFG costspresented in Table III–1 are not strictlycomparable to the other costs cited inthe table. Federal Phase II RFG willprovide large VOC reductions inaddition to NOX reductions. FederalRFG is required in nine cities with theNation’s worst ozone nonattainmentproblems; other nonattainment areashave chosen to opt into the program aspart of their attainment strategy. Themandated areas and those areas in theOTAG region that have chosen to optinto the program are areas wheresignificant local reductions in ozoneprecursors are needed; such areas mayvalue RFG’s NOX and VOC reductionsdifferently for their local ozone benefitsthan they would value NOX reductionsfrom RFG or other programs for ozonetransport benefits.

The EPA notes that there are also anumber of less expensive measuresrecently undertaken by the Agency toreduce NOX emission levels that do notappear in Table III–1. These actionsinclude: (1) The Title IV NOX reductionprogram, (2) the Federal locomotivestandards, (3) the 1997 proposedFederal nonroad diesel enginestandards, (4) the Federal heavy dutyhighway engine 2g/bhp-hour standards,and (5) the Federal marine enginestandards. These lower cost actions donot represent a useful measure of the


8 However, in the Regulatory Analysis of thisaction, EPA evaluates the economic impact ofincluding the MOU in the baseline for the electricpower industry.

9 All estimates of I/M program cost effectivenessin this rulemaking are presented in terms of the costper annualized summer ton of ozone precursor, i.e.,the cost per ton of VOC or NOX. Cost perannualized summer ton is calculated as the totalcost of the program divided by the number of tonsthat would be reduced annually if the level ofreduction achieved during the summer wereachieved year round. It thus understates the costper actual ton of reduction of ozone precursors. TheEPA believes this procedure is appropriate becauseI/M programs reduce other pollutants beside ozoneprecursors (e.g., air toxics and carbon monoxide(CO)).

willingness to make reasonableexpenditures to reduce NOX emissionsin order to achieve air quality goals.Decisions to undertake these measuresare low cost steps toward NOX

reduction. Though these actions arevery cost effective, the Agency mustnow focus on what other measures exist,at a potentially higher cost-effectivenessvalue, that can further reduce NOX

emissions. The Agency is focusing onthese other actions because they mayalso be of reasonable cost effectivenessand obtaining these reductions are lesscostly than further local reductions ofVOC and NOX in nonattainment areas.Table III–1 is thereby useful as areference of the next higher level of NOX

reduction cost effectiveness that theAgency considers reasonable toundertake.

The Agency is also aware that to comeinto attainment with the new ozoneNAAQS, many localities will spendseveral thousand dollars per ton of NOX

or VOC reduction.b. Determining the Cost Effectiveness

of NOX Controls. In an effort to considera cost-effective mix of controls on whichto base each component of the proposedbudget (i.e., electricity generatingsources, nonutility point sources, areasources, and mobile sources) the Agencyconsidered the average costeffectiveness of alternative levels ofcontrols for each source. Among theplausible levels of control are thecontrols included in OTAG’srecommendations.

The average cost effectiveness of thecontrols assumed in calculating eachsector’s budget component wascalculated from a baseline level thatincluded all currently applicableFederal or State NOX control measures.The baseline did not include Phase 2and Phase 3 of the OTC NOX MOU sincethey have not yet been adopted by allthe involved States 8; if the MOU wereincluded in the baseline, the overallcosts would be lower. The costs andemissions reductions for point sourcesare determined using an emissions cap-and-trade approach since EPA believesthat this approach is the most cost-effective way for point sources to meetan emissions budget, and EPA expectsthat States are also interested inemploying the most cost-effectiveapproach. Table III–2 shows in the firstcolumn of numbers the average cost perton of NOX removed during the ozoneseason of various potential EPA actions,arranged by source sector. The action is

presented in the form of a regionwidebudget for each source sector (i.e., theelectric power industry and otherstationary sources), and the cost-effectiveness values are for the ozoneseason. The Agency used its estimates ofthe average cost effectiveness ofreducing NOX emissions during theozone season to develop the budgetcomponents for the electric powerindustry and other stationary sources.

The next three columns in the Tablecontain the average cost per ton of NOX

annually reduced, the incremental costper ton of NOX reduced during theozone season, and the incremental costper ton of NOX annually reduced. Theaverage cost per ton of NOX reducedannually is the annual costs of a sourcecategory complying with a NOX budgetcomponent option divided by the NOX

emissions reductions that occurthroughout the entire year. Theincremental cost per ton of NOX

reduced during the ozone season is thedifference in the annual cost of theoption examined and the next cheapestoption divided by the difference inseasonal NOX reduction in these twooptions. The incremental cost per ton ofNOX reduced annually is the differencein the annual cost of the optionexamined and the next cheapest optiondivided by the difference in the annualNOX reduction in these two options. Forthe option with the lowest annual costfor each source category’s NOX budgetcomponent, the average and incrementalcosts are the same, which assumes thatultimately the cheapest option is noadditional controls, or the baseline.

The EPA has provided these othermeasures of cost effectiveness toprovide additional perspective on thedecision that the Agency made for thelevel of each source category budgetcomponent. Each of these cost-effectiveness measures has advantagesin being used in conjunction with otherfactors to make a decision onenvironmental controls under certaincircumstances. They each also havelimitations. The annual measures arevaluable since there are NOX reductionbenefits that the public will gainthroughout the year from controls on thesources covered in this rulemaking.They do not, however, focus as well onthe primary objectives of the ozonetransport rule of providing reductions ofozone during the time of year when itdoes the most harm and in whichexceedances of the ozone standards arelikely to occur. The incrementalmeasures are valuable since they showthe additional costs of the additionalreductions from increasing thestringency of pollution controls.However, for this rulemaking, it is

difficult to compare the incrementalcosts of increasing levels of stringencyfor large stationary sources with otherAgency and State analyses that havebeen developed in the past. Forinstance, because incremental costcomparisons will differ depending onthe size of the increment in stringencybeing considered, care must be used inusing incremental cost estimates fromearlier rulemakings.

The Agency solicits comments on itsuse of average seasonal costeffectiveness as the measure it wants torely on to judge the cost effectiveness ofthe NOX reductions that will occur fromthe NOX budget components that EPAhas chosen for the electric powerindustry and other stationary sources.Commenters offering other measures, orcombinations of cost-effectivenessmeasures, that EPA needs to consider,should provide their rationale for theirviews.

The EPA is not choosing to base itsproposed budgets on an expansion of I/M programs beyond the extent requiredby the CAA or otherwise reflected inexisting SIPs in its calculation of StateNOX budgets. The cost effectiveness ofI/M programs in reducing ozoneprecursors (including both NOX andVOC) can vary widely due to differencesin the design and operation ofindividual I/M programs. The EPA’scurrent estimate of the cost effectivenessof I/M programs ranges from $500 to$3,000 per ton of ozone precursor, on anannualized summer ton basis.9Although this range suggests that thecost effectiveness of I/M programs inreducing ozone precursors (includingboth NOX and VOC) may be comparableto the cost of the utility NOX reductionsproposed in today’s rulemaking, the costeffectiveness of I/M programs inreducing NOX alone would besignificantly higher since most of theozone precursor reductions fromenhanced I/M programs are VOCreductions. Both VOC and NOX

reductions are valuable for achievinglocal attainment, but as discussed insection II, Weight of EvidenceDetermination of SignificantContribution, today’s rulemaking


10 This cost represents the midpoint of theexpected range of $2,600 to $3,500 per ton(depending on the degree of expansion of theprogram), on an annualized summer ton basis, forboth VOC and NOX. All estimates of RFG costeffectiveness in this rulemaking are presented in

terms of the cost per annualized summer ton ofozone precursor, i.e., the cost per ton of VOC orNOX. Cost per annualized summer ton is calculatedas the total cost of the programs divided by thenumber of tons that would be reduced annually ifthe level of reduction achieved during the summer

were achieved year round. It thus understates thecost per actual ton of reduction of ozone precursors.The EPA believes this procedure is appropriatebecause the use of RFG reduces other pollutantsbesides ozone precursors (e.g., air toxics and CO).

focuses on reducing NOX emissionssince such reductions offer greaterpotential for reducing regional transportthan would VOC reductions.

Similarly, EPA is not choosing to baseits proposed budgets on an expansion ofFederal Phase II RFG beyond its currentextent in its calculation of State NOX

budgets. The EPA’s current estimate of

the cost effectiveness of Federal Phase IIRFG ranges from $2,600 to $3,500 perton of ozone precursor, on anannualized summer ton.10 This costexceeds the cost of the utility NOX

reductions proposed in today’srulemaking. Furthermore, the costeffectiveness of Federal Phase II RFGprograms in reducing NOX alone would

be significantly higher since most of theozone precursor reductions from RFGwould be in the form of VOC reductionswhich, while valuable for achievinglocal attainment, are not the focus oftoday’s action since NOX reductionsoffer greater potential for reducingregional transport.

TABLE III–2.—COST EFFECTIVENESS OF OPTIONS FOR THE OZONE SEASON NOX BUDGET COMPONENTS FOR SELECTEDSOURCE CATEGORIES

[In 1990 dollars per ton of NOX reduced]

Source category: Options for ozone season NOX budget components

Averagecost per tonof NOX re-duced dur-

ing theozone sea-

son

Averagecost per tonof NOX re-duced an-

nually

Incrementalcost per tonof NOX re-duced dur-

ing theozone sea-

son

Incrementalcost per tonof NOX re-duced an-

nually

Electric Power Industry:815 thousand tons ..................................................................................................... $1,100 $850 $1,100 $850652 thousand tons ..................................................................................................... 1,300 1,050 2,100 2,100489 thousand tons ..................................................................................................... 1,700 1,400 3,600 3,400391 thousand tons ..................................................................................................... 2,100 1,750 6,350 5,200326 thousand tons ..................................................................................................... 2,450 2,000 8,700 6,850

Other Stationary Sources484 thousand tons 1 .................................................................................................. 1,450 750 1,450 750466 thousand tons 2 .................................................................................................. 1,650 900 4,400 2,150380 thousand tons 3 .................................................................................................. 2,750 1,400 6,300 3,050

1 This measure approximates the emission reductions that would be obtained if Level 1 controls were placed on medium sized sources andLevel 2 controls were placed on large sized sources. The calculation process used to calculate cost for nonutility units selects control measures(at a State level) so that the cost minimizing set of controls that meet the required emissions reductions are chosen. This approach provides adownward bias to the costs and cost-effectiveness values compared to any way the States might obtain the emission reductions, including con-sideration of other factors (e.g., administrative costs that are not included in this analysis). While a least-cost approach simulates either costlessemissions trading or a cost minimizing command and control approach with perfect information, either approach is unlikely to include the smallersources used in this analysis.

2 This option considers a 70 percent reduction of summer NOX emissions from large sources and RACT controls on medium size sources. Thisapproach is what OTAG recommended occur, if EPA considered reductions of electric power industry emissions of equivalent to .15 pounds ofNOX per MMBtus, or an 85 percent reduction of uncontrolled levels, whichever is less stringent. The EPA’s proposal for the NOX budget compo-nent for the electric power industry is based on a comparable level of controls to the .15/85 percent reduction.

3 This measure approximates budgets of an 80 percent control of baseline emissions for large sized sources and Level 1 control on the me-dium sources. The calculation process used to calculate cost effectiveness on nonutility units provides a downward bias for the reasons ex-plained in the above footnote.

NOTE: The options for electric power industry NOX budget component are based on pollution controls on electric generation units meetingsummer season NOX emission limitations in pounds of NOX per million Btus of heat input of .25, .20, .15, .12, and .10, respectively. The cost-ef-fectiveness calculations are based on implementing these controls through a cap-and-trade program. The controls on which the options for theNOX budget component for Other Stationary Sources are based are provided in the footnotes. The cost-effectiveness calculations are based oneach State implementing a least-cost approach to compliance.

Considering the $1,000 to $2,000 perton average cost-effectiveness rangefrom Table III–1, and the level of controlachievable with each sector’s NOX

control technologies, EPA believes thatit is reasonable to require the followinglevels of reductions: (1) For the electricpower industry, a budget component of489 thousand tons (which is equivalentto an average NOX emission rate of 0.15lb/MMBtu) since it is both cost effectiveand achievable, on average, by theaffected sector sources; and (2) for otherstationary sources, a budget componentof 466 thousand tons, which is

consistent with OTAG’srecommendation that nonutility pointsource controls be comparable instringency to the selected level ofelectric power industry controls, whichfor .15 lbs/MMBtus would be 70 percentcontrol on large-sized sources (e.g.,boilers greater than 250 MMBtu/hour)and RACT controls on medium-sizedsources (e.g., sources emitting between1 and 2 tons per day). The RACTcontrols result in NOX reductionsgenerally in the range of 25–50 percent.This corresponds closely with theOTAG recommendation given the

proposed level of electric powerindustry controls, and EPA believes it isa reasonable level of control based onaverage cost effectiveness as discussedabove.

For mobile sources, EPA proposesconstructing the budget component byincluding: (1) those controls that wouldbe implemented federally or by States inthe absence of today’s action, and (2)those controls that are viewed today asbeing feasible in the 2007 time frameand that meet EPA’s proposed NOX cost-effectiveness criterion. The EPA did notinclude in the proposed mobile source


11 U.S. Environmental protection Agency, ‘‘Round3 Analysis of Cap-and-Trade Strategies to Lower

NOX Emissions from Electric Power Generation inOTAG’’, March 25, 1997.

budget component a number of controlmeasures that offer multipollutantbenefits and hence may be attractivecontrol measures for local attainmentand maintenance. These measuresinclude Tier 2 light-duty vehicle andlight-duty truck standards and moreextensive implementation of I/M andFederal Phase II RFG. When comparedwith other available options, thesemeasures are reasonable controlmeasures when these measures’ fullrange of benefits are considered,including CO, toxic air pollutants, andVOC benefits in addition to their NOX

benefits. Some of these measures, suchas I/M, RFG and Clean Fuel Fleets, canbe implemented in specific areasseeking to meet local air qualityobjectives rather than region ornationwide. While EPA did not chooseto assume their regionwideimplementation in calculating NOX

budgets because their cost effectivenessfor NOX reductions alone did not justifyincluding them in the set of assumedcontrols, EPA continues to believe thatthese measures’ nonozone benefits andVOC benefits (which provide localozone reductions but tend not toprovide significant reductions inregional ozone transport) make themattractive for areas seeking to meet localozone attainment, or maintenanceobjectives, or other air quality goals.Although these strategies were notincluded in the budget calculation,States can opt to implement thesemeasures as part of their SIP revision inresponse to today’s proposal. Each ofthese programs is discussed in moredetail below.

The EPA’s approach to the NOX

budget component for the electric powerindustry relies on the consideration ofthe States using a cap-and-tradeprogram to reduce emissions from thissource category. The Agency’s analysisshows that this type of approach is 25percent more cost effective (lower incost per ton reduced) than the use of acomparable traditional command-and-control approach, such as setting rate-based NOX emissions limitations at .15

lbs of NOX per million Btus of heatinput at every source.

The EPA did not examine theimplications of each State setting up itsown trading programs for the electricpower industry, which could occur ifthe Agency is unable to work with theStates to put together a viable tradingprogram across the 23 jurisdictionscovered in this rulemaking. Based onanalysis done for OTAG in the past, theAgency believes this type of approachwould lead to somewhat higher costs,but would still be less expensive than acommand-and-control program in everyState. This conclusion is based on workthat EPA did for OTAG, where itdivided a similar area to the onecovered in this rule into five tradingzones versus a single trading zone.11

Although the costs did increase, theywere not dramatically higher. Furthersupport for this conclusion results fromthe examination of EPA’s RegulatoryAnalysis supporting this proposedrulemaking. The Agency found that inthe vast majority of States, electricgeneration units would make significantNOX emissions reductions under a cap-and-trade system that allowed tradingbetween all the States covered. Thismeans that the electric power generationunits that can reduce NOX emissionsmost cost-effectively are spreadthroughout the region covered by theOzone Transport SIP Rulemaking.

In calculating States’ budgets, EPAassumed implementation of thefollowing mobile source controlmeasures in addition to those measuresalready implemented or otherwisepromulgated in final form:

Nonroad

• Federal Small Engine Standards,Phase II

• Federal Marine Engine Standards• Federal Heavy-Duty (≥50 hp)

Nonroad Standards, Phase I• Federal Reformulated Gasoline,

Phase II (in statutory and current opt-inareas)

• Federal Locomotive Standards• 1997 Proposed Nonroad Diesel

Engine Standards

Highway

• Tier 1 Light-Duty and Heavy-DutyVehicle Standards

• Enhanced I/M (serious and aboveareas)

• Low Enhanced I/M (rest of OTR)• Basic I/M (mandated areas)• Clean Fuel Fleets (mandated areas)• Federal Reformulated Gasoline,

Phase II (in statutory and current opt-inareas)

• National Low Emission VehicleStandards

• Heavy-Duty Engine 2 g/bhp-hourstandard

• Revisions to Emissions TestProcedure

With the exception of the Clean FuelFleets, I/M, and RFG programs, all ofthese control measures are or will beimplemented nationally (or in the 49States outside of California). The EPAassumed that the Clean Fuel Fleets, I/M,and RFG programs would beimplemented to the extent required bythe CAA or existing SIPs, or as reflectedin current levels of State opt-in to theseprograms. The reader is referred tosections III.B.5 and III.B.6 for a moreextensive discussion of the developmentof the highway vehicles and nonroadbudget components, respectively.

At the current time, the standardspresumed for locomotives, marineengines, small gasoline engine, nonroaddiesel engines, and heavy-duty highwayengines in calculating State NOX

budgets represent the most technicallyfeasible emissions performance levelsachievable in the 2007 time frame. Forthis reason, the Agency did not evaluateany more stringent standards for thesesources in its calculation of State NOX

budgets.c. Summary of Measures Assumed in

Proposed Budget Calculation. The EPAis proposing to calculate the budgetsdescribed in this section by assumingthe application of the most reasonable,cost-effective controls for the purpose ofachieving regional NOX reductions.Table III–3 summarizes the controls thatwere assumed for each source sector.More detailed discussions of thecontrols assumed are contained in thesections that describe each sector.

TABLE III–3.—SUMMARY OF NOX CONTROL MEASURES APPLIED IN THE DEVELOPMENT OF PROPOSED STATEWIDESEASONAL NOX EMISSIONS BUDGETS *

Emissions Source Sector Controls Applied in Developing Proposed Statewide NOX EmissionsBudgets for 2007

Large Electricity Generating Devices (fossil-fuel burning electric utilityunits and nonutility units serving electricity generators 25MWe orgreater).

Statewide seasonal tonnage budget based on applying a NOX emis-sion rate of 0.15 lb/MMBtu on all applicable sources.


TABLE III–3.—SUMMARY OF NOX CONTROL MEASURES APPLIED IN THE DEVELOPMENT OF PROPOSED STATEWIDESEASONAL NOX EMISSIONS BUDGETS *—Continued

Emissions Source Sector Controls Applied in Developing Proposed Statewide NOX EmissionsBudgets for 2007

Nonutility point sources (boilers, reciprocating internal combustion en-gines, turbines, cement kilns, etc.).

70 percent controls on large-sized sources (e.g., >250 MMBtu/hour)RACT controls on medium-sized sources (e.g., 100–250 MMBtu/hour).

Nonroad Sources (commercial marine engines, small engines such aslawn and garden equipment, and larger engines such as constructionequipment and locomotives).

Federal small engine standards (Phase II)Federal marine engine standards (diesel >50 horsepower)Federal locomotive standards 1997 proposed nonroad diesel engine

standards.Highway Vehicle Sources (cars, trucks, buses, motorcycles—gas and

diesel highway engines).National Low Emission Vehicle Program2004 Heavy-Duty Vehicle Standards.Revisions to Emissions Test Procedure **

Area (Small Stationary) Sources (open burning, small commercial, in-dustrial and residential fuel combustion devices).

Full implementation of programs required by the CAA and outlined inexisting State implementation plans.

* Controls already required under the 1990 Amendments to the CAA and those applied through existing SIPs were assumed in the develop-ment of the statewide NOX budgets but are not explicitly listed in this table.

** Other measures used in developing some state budgets include I/M programs (where mandated), Federal Phase II RFG (where mandatedor in areas which have already opted into the program as of the date of today’s rulemaking ), and clean fuel fleet programs. Potential reductionsfrom Tier 2 light-duty vehicle standards were not incorporated since they are still under review.

In determining what controls toassume in calculation of the proposedbudgets, EPA considered theconclusions that were reached in theOTAG process as well as the cost-effectiveness rationale described above.Any special effort to address ozonetransport, such as today’s action, mustbe part of an integrated regulatorysolution developed by EPA and States toprovide national compliance with thecurrent (1-hour) and new (8-hour)NAAQS. The OTAG’s air qualitymodeling showed that even with themost stringent control measures thatwere evaluated for NOX and VOC, notall areas would come into attainmentwith the current ozone NAAQS. It isalso evident that with no actions toaddress ozone transport, some areas willhave ‘‘background levels’’ that will notallow even aggressive local controls tobring them into compliance, and otherswill face severe measures in an effort todo so. Therefore, today’s actioncomplements local programs to addressattainment with the ozone NAAQS. TheEPA recognizes the need to providepollutant reductions where it would bemore cost effective to do so rather thanplace all of the burden on localities. Therecent RIA in support of the new ozonestandard shows that the last tons oflocalized NOX and VOC reductionneeded for meeting that standard insome areas can easily cost from $5,000to $10,000 a ton to achieve. Avoidingsuch expenditures is a major objectiveof today’s action.

3. Proposed Assumptions for ElectricUtilities

This section presents the rationaleand resulting proposed State-by-StateNOX budget components for fossil fuel-burning electric utility units under

today’s action. Three different proposedNOX emission scenarios and theirresulting State-by-State emissionallocations are presented.

a. Affected Entities. The sources ofinformation used in this section are: (1)for electric utility units submitted byutilities to EPA under the requirementsof 40 CFR part 75 (emissions monitoringprovisions of title IV, section 412; and(2) for nonutility units (e.g., unitsowned by Independent PowerProducers), projected by EPA using theIntegrated Planning Model (IPM) frombase year information supplied to theNorth-American Electricity ReliabilityCouncil (NERC), Energy InformationAgency (EIA), and trade sources.

Utility emissions representapproximately 36 percent of the totalanthropogenic NOX emissions afterapplication of current CAA controls inthe States covered by today’s action.The calculations described below applyto large sources that have generatorsgreater than 25 MWe. The EPA believesthat it is reasonable to assume no furthercontrol of emissions from smallersources based on the current availabilityof emissions and utilization data forthese sources. While EPA has quality-assured NOX emissions and utilizationdata for electric utility units larger than25 MWe, such data are not currentlyavailable for smaller units. Therefore,the contribution of the smaller sourcesto the utility component of each State’sbudget cannot currently be assessedwith certainty. The EPA solicitscomment on: (1) whether sources equalto or smaller than 25 MWe should beincluded in the utility component ofeach State’s budget, and (2) sources ofemissions and utilization data forsources equal to or smaller than 25MWe.

Larger sources were found to be largecontributors to NOX emissions and, withthe application of NOX controls, werefound to be able to achieve reductionscost-effectively. Specifically, EPAperformed an analysis to determine thecost effectiveness of NOX controlsapplied to large utility boilers and howit compared to other sector NOX

controls. The results indicate thatcontrolling emissions to an average levelof 0.15 lb/MMBtu was cost effective forlarge utility boilers (see section III.B.2.).

This section does not includecombustion units which generateelectricity for purposes internal to aplant. These units, for the purposes ofthe overall State budget, are consideredindustrial units and are included in thecorresponding section. Some of theseunits (e.g., units with capacity greaterthan 25 MWe or the equivalent inthermal output, measured in MMBtu)may more appropriately be includedwith the utility sector emissions, withsimilar required levels of control, sincecontrols for these units may be as costeffective as utility unit controls.Additionally, certain large industrialcombustion sources (e.g., boilers with aheat input larger than about 250MMBtu/hour, used only for steam, notelectricity generation) may be able toachieve levels of control equal to that ofthe electric utility units withcomparable cost effectiveness. The EPAsolicits comment on the appropriatenessof including such units in the utilityemissions by assuming the same level ofcontrol from these units as from utilityunits.

b. Methodology Used to Determine theProposed Electric Utility BudgetComponent. The proposed emissionsbudget component for electric utilities(in tons) is calculated as the product of


two separate components: (1) sourceactivity level, measured in MMBtu; and(2) pollutant emission rate, measured inpounds of pollutant per MMBtu. Sinceboth components influence the

emissions, it is important to use themost accurate information whencalculating each component.

i. Proposed Utility Budget ComponentCalculation and Alternatives. Four

alternatives were considered forcalculating the utility budgetcomponent (Table III–4).

TABLE III–4.—SUMMARY OF ALTERNATIVES

Alternative Activity level (heat input) NOX rate (lb/MMBtu)

1 .................. Future Activity (current with estimated growth to 2007) ............. Higher of:(1) 0.15 or(2) an 85% reduction of historic emission rate.

2 .................. Current Activity ............................................................................ Higher of:(1) 0.15 or(2) an 85% reduction of current emission rate.

3 .................. Future Activity (current with estimated growth to 2007) ............. 0.15.4 .................. Current Activity ............................................................................ 0.15.

After evaluating each alternative, EPAis proposing to base the electric utilityemissions on a projected future activitylevel and a desired emission rate(scenario 3). The following subsectionsdiscuss each technique separately.Detailed results of each alternative areavailable in the TSD.

Alternative 1: Future Activity WithHistoric (or Desired) Emission Rates

This technique involves calculatingthe emissions based on a projectedfuture activity level (e.g., using anelectric utility generation forecastingmodel such as IPM) and the higher of:(1) a desired emission rate, or (2) a rateresulting from a percent reduction fromsome past baseline year emission rate(e.g., 1990). This was the technique usedin many OTAG analyses. On its face,this approach may appear to equitablydetermine an emissions budget.However, this requires thedetermination of the NOX emission ratesfrom 1990 for every unit in a State’sinventory. In addition to the accuracyproblems encountered in determiningan historic emissions rate, this approachrelies on a percent reduction from anhistoric rate, which benefits States thatwere higher emitters over States thathad cleaner fuels. Thus, EPA believesthat this approach is neither the mosttechnically accurate nor the mostequitable.

Alternative 2: Current Activity WithCurrent (or Desired) Emission Rates

This technique involves calculatingemissions based on a current activitylevel (e.g., 1995 or 1996) and the higherof: (1) a desired emission rate, or (2) arate resulting from a percent reductionfrom a current year (e.g., 1996) forwhich accurate emission rates per unitexist. The benefit of this approach isthat both activity and emission rates areavailable for all utility units included inthe emissions budget. This approach

requires that all changes in theutilization of utility units beaccommodated within the utility budgetcomponent. However, to the extent thisapproach relies on percent reduction, itwould benefit currently high emittersand disadvantage units that installedcontrols in order to comply with otherprovisions of the Act. Thus, thoughsimpler (because it relies on currentactual data without projections), thisapproach may not be viewed asequitable.

Alternative 3: Future Activity WithDesired Emission Rate

This technique involves calculatingthe utility budget component based ona future activity level (i.e., inflating thecurrent measured utilization by anestimated growth factor) and a desiredemission rate. The benefit of thisapproach is that it acknowledges theinherent inequity of using any past orcurrent emission rates and treats allunits equally based on a future standardemission rate (e.g., 0.15 lb/MMBtu).Further, by projecting future changes inutilization, this approach more directlyaccommodates changes in unitutilization to the extent such futureutilization can be reasonably projected.The potential for error in making suchprojections is minimized when startingwith actual unit-specific utilizations.Thus, though more complicated thanthe previous technique (because of itsreliance on a projection of industrygrowth), this approach is viewed asmore equitable, particularly since othersource categories included in the overallState-specific budget reflect growth.

Alternative 4: Current Activity WithDesired Emission Rate

This technique involves calculatingemissions based on a current activitylevel (e.g., 1995 or 1996) and a desiredfuture emission rate. Similar to theabove approach, this approach

acknowledges the inherent inequity ofusing any past or current emission ratesand treats all units equally based on adesired standard emission rate (e.g.,0.15 lb/MMBtu). Unlike the aboveapproach, however, it uses currentactivity to determine the utility budgetcomponent, providing for the highestdegree of accuracy. Changes in theutilization of utility units must beaccommodated within the utility budgetcomponent. This approach is simple(because it relies on current actual datawithout projections), but it may beviewed as less equitable for States withsignificantly higher projectedutilization.

ii. Seasonal Utilization. The proposedutility budget component is based onutilization over the course of a summerseason (i.e., May 1 to September 30).Utilization can be significantly differentfrom season to season and the degree ofthis difference can vary from State toState (e.g., some States can have muchhigher utilization in the summer due,for example, to high usage of airconditioning or shifting load to anotherState). Thus, it is important toaccurately characterize the summerusage of every State separately. Becauseof the high seasonal variability, it is lessaccurate to simply take total annualutilization and divide by the number ofsummer months. Similarly, because ofthe geographic variation, it is lessaccurate to take regionwide summerutilization and equally apportion theutilization to all States.

There are currently only two sourcesof information that provide actual dataand take account for seasonal and Statevariations in utilization: (1) the EIA’sForm 767, and (2) EPA’s EmissionTracking System containing datareported by utilities in accordance with40 CFR part 75. Both sources containunit-by-unit utilization; EIA on amonthly basis and EPA on an hourly


12 It should be noted that units owned byIndependent Power Producers were not included inTable III–5 since neither their 1995 nor their 1996

utilizations are known. The projected 2007utilization for these units is, however, included inthe utility portion of each State’s budget.

basis. There is, however, one importantdifference: while the method used todetermine and report utilization to EIAcan differ significantly from utility toutility, the information submitted toEPA is determined and reported usingconsistent techniques as required by 40CFR part 75.

Thus, EPA is proposing to use itsinformation to determine each unit’s(and thereby each State’s) utilization forthe period beginning May 1 and endingSeptember 30. It should be noted that inthe case of units owned by nonutilitysources (e.g., Independent PowerProducers), EPA does not have currentutilization information available. Forthe purpose of estimating the emissions

for these units, EPA is proposing to usethe IPM-predicted utilization for theyear 2007. The predicted utilizations areprojected from base year informationsupplied to the NERC, EIA and tradesources.

One way of accounting for State-by-State shifts in electricity generation,from 1 year to the next, during theperiod beginning May 1 and endingSeptember 30, is to calculate the utilitybudget component based on a compositeutilization: using the State-by-Stateutilization for the higher of 1995 or 1996(i.e., for each State, using the higher ofits overall 1995 or 1996 summerutilization). This is the approachproposed by EPA. Though this approach

results in a slightly exaggerated baselineutilization, the inflation to emissions ismoderate and the equity that it providesis potentially significant for somesituations. Table III–5 12 compares theState-by-State utilizations using thecomposite method versus using 1996only. The impact is most evident on theDistrict of Columbia (which has a 1995utilization substantially greater than its1996 utilization) for which 1996 mayhave been an unrepresentative summer.Another option would be to use theannual average of the highest 2 out of3 recent years (e.g., 1995, 1996, and1997) when data for 1997 becomesavailable. The EPA solicits comment onboth approaches.

TABLE III–5.—COMPARISON OF STATE-BY-STATE 1995, 1996 AND ‘‘COMPOSITE’’ UTILITY UNIT SUMMER UTILIZATIONS

State 1995 Utiliza-tion (MMBtu)

1996 Utiliza-tion (MMBtu)

State-by-Statehigher of 1995or 1996 utiliza-

tion

Alabama ....................................................................................................................................... 342,060,000 349,950,000 349,950,000Connecticut ................................................................................................................................... 26,500,000 40,890,000 40,890,000Delaware ...................................................................................................................................... 30,890,000 33,830,000 33,830,000District of Columbia ...................................................................................................................... 2,030,000 130,000 2,030,000Georgia ......................................................................................................................................... 349,310,000 335,330,000 349,310,000Illinois ............................................................................................................................................ 331,120,000 344,470,000 344,470,000Indiana .......................................................................................................................................... 511,420,000 512,420,000 512,420,000Kentucky ....................................................................................................................................... 397,540,000 395,800,000 397,540,000Maryland ....................................................................................................................................... 130,530,000 123,060,000 130,530,000Massachusetts .............................................................................................................................. 96,290,000 100,150,000 100,150,000Michigan ....................................................................................................................................... 280,730,000 287,790,000 287,790,000Missouri ........................................................................................................................................ 267,710,000 270,240,000 270,240,000New Jersey ................................................................................................................................... 44,140,000 43,310,000 44,140,000New York ...................................................................................................................................... 249,260,000 223,360,000 249,260,000North Carolina .............................................................................................................................. 286,710,000 310,600,000 310,600,000Ohio .............................................................................................................................................. 549,050,000 565,990,000 565,990,000Pennsylvania ................................................................................................................................ 445,030,000 481,950,000 481,950,000Rhode Island ................................................................................................................................ 320,000 11,940,000 11,940,000South Carolina .............................................................................................................................. 130,150,000 150,370,000 150,370,000Tennessee .................................................................................................................................... 279,730,000 268,880,000 279,730,000Virginia .......................................................................................................................................... 150,870,000 136,740,000 150,870,000West Virginia ................................................................................................................................ 269,840,000 302,850,000 302,850,000Wisconsin ..................................................................................................................................... 196,840,000 191,730,000 196,840,000

iii. Growth Considerations. In general,new units built to meet economicgrowth are lower emitting than the olderunits they augment or replace. Thus,though the industry’s fuel utilizationmay increase over time, the industry’saverage NOX rate may decrease asnewer, cleaner units are built andoperated, and total emissions may ormay not increase.

Two approaches were considered foraccommodating potential emissionsgrowth under an emissions budget. Oneapproach was to calculate emissionsbased on recent historic utilization, aswas done in the sulfur dioxide program

under title IV of the Act. Under thisapproach, States with significantprojected increases in utilization wouldbe required to either: (1) reduce theirNOX rates further, or (2) burn fuel moreefficiently in order to compensate. Forsuch States, the ability to tradeemissions regionwide is particularlyattractive because States with lowincreases or decreases in utilization cantrade emissions with States havingsignificantly increased utilization.

An alternative approach was toproject each State’s change in utilizationfrom current levels to some future yearand set a budget based on that future

year’s utilization. This approachdirectly addresses industry growth.Additionally, this was the type ofapproach taken by OTAG ininvestigating various State budgets.Thus, EPA is proposing to use this typeof approach for addressing activitygrowth and, as described below, usingthe IPM growth projections. However,there are several other ways in whichgrowth can be reflected in budgetallocations. For example, recognizingthat several utility companies span morethan one State and that electricity isdispatched across State boundaries, anaverage regional growth rate could be


applied to each State’s currentutilization. The EPA solicits commenton these and other approachesaddressing activity growth inestablishing a statewide utility budgetcomponent.

c. Summary and Proposed UtilityBudget Components. For reasonsdiscussed in the previous section, EPAis proposing to calculate each State’ssummer season electric utility emissionsusing a specific NOX emission rate andthe projected summer season utilizationof the year 2007. Specifically, EPAproposes calculating each State’s utilityNOX budget component by multiplying:(1) each State’s summer activity level,measured in MMBtu, (EPA selected thehigher of each State’s overall 1995 or1996 summer utilization), by (2) eachState’s projected growth between 1996and 2007 (using the IPM model), by (3)a NOX rate of 0.15 lb/MMBtu. Theresulting figure, in lbs, was divided by

2000 (lbs per ton) to determine tons. Forelectricity-generating units owned bynonutilities (e.g., Independent PowerProducers), EPA used their IPM-predicted utilization for 2007 in place ofsteps (1) and (2). The EPA compared theIPM-generated growth factors of eachState to those developed by OTAG forthe electric utility sector in every State.In general, the IPM-predicted growthwas about 60 percent higher than thegrowth projected by OTAG. Regionwide,the OTAG-predicted growth was about 6percent from 1996 to 2007, and the IPM-generated growth was about 15 percentfor the same period. However, for someStates such as Alabama and New Jersey,the IPM growth factor was lower thanthe OTAG growth factor. The TSDdescribes in detail how the IPM andOTAG growth factors were calculated.

For the proposed rule, EPA selectedthe IPM’s State-by-State growth factorsover the growth factors developed by

OTAG. Unlike the OTAG electric utilitygrowth projections, the IPM’s were notdeveloped separately for each State, butwere developed by analyzingperformance of utilities as a regionwidesystem. Therefore, the IPM growthfactors are considered to be moreconsistent than the OTAG growthfactors. The EPA solicits comment onthe appropriateness of using the IPMmodel to determine State-specificgrowth factors for the period between1996 and 2007. Further, EPA solicitscomment on what other reasonableregionwide approaches can be used todevelop growth factors.

Table III–6 presents the resultingproposed utility (and electricity-generating nonutility) budgetcomponents per State along with the2007 CAA base.

TABLE III–6.—STATE-BY-STATE BUDGET COMPONENT FOR ELECTRICITY-GENERATING UNITS

State 2007 CAAbase (tons)

Proposedbudget com-ponent (tons)

Percentreduction

Alabama ....................................................................................................................................... 81,704 26,946 67Connecticut ................................................................................................................................... 5,715 3,409 40Delaware ...................................................................................................................................... 10,901 4,390 60District of Columbia ...................................................................................................................... 385 152 61Georgia ......................................................................................................................................... 92,946 30,158 68Illinois ............................................................................................................................................ 115,053 31,833 72Indiana .......................................................................................................................................... 177,888 48,791 73Kentucky ....................................................................................................................................... 128,688 35,820 72Maryland ....................................................................................................................................... 35,332 11,364 68Massachusetts .............................................................................................................................. 28,284 12,956 54Michigan ....................................................................................................................................... 82,057 25,402 69Missouri ........................................................................................................................................ 92,313 22,932 75New Jersey ................................................................................................................................... 14,553 5,041 65New York ...................................................................................................................................... 39,639 24,653 38North Carolina .............................................................................................................................. 83,273 27,543 67Ohio .............................................................................................................................................. 185,757 46,758 75Pennsylvania ................................................................................................................................ 125,195 39,594 68Rhode Island ................................................................................................................................ 773 905 ¥17South Carolina .............................................................................................................................. 43,363 15,090 65Tennessee .................................................................................................................................... 71,994 19,318 73Virginia .......................................................................................................................................... 45,719 16,884 63West Virginia ................................................................................................................................ 83,719 23,306 72Wisconsin ..................................................................................................................................... 51,004 15,755 69Total .............................................................................................................................................. 1,596,255 489,000 69

4. Proposed Assumptions for OtherStationary Sources

a. Affected Entities. This sectionpresents the rationale and resultingproposed State-by-State NOX budgetcomponents for other stationary sources,specifically, the area and nonutilitypoint source sectors. Area sources ofNOX emissions include, for example,emissions from wildfires, open burning,and residential water heaters. Emissionsfrom area sources represent only 7percent of total anthropogenic NOX

emissions in the States covered by

today’s action (based on OTAG 2007CAA emissions). The highest percentagein any one State is 18 percent.Nonutility point sources include boilers,process heaters, reciprocating internalcombustion engines, turbines, cementkilns and other categories. Emissionsfrom sources in this sector represent 14percent of the total anthropogenic NOX

emissions in the States covered bytoday’s action, with a range of 3–22percent.

b. Methodology Used to Determine theProposed Area and Nonutility Point

Source Budget Components. Theproposed State-by-State seasonal (May1–September 30) budget components forthe area and nonutility point sectorsgenerally reflect the OTAGrecommendations. For area sources,EPA proposes applying OTAG Level 0(i.e., no new controls). The EPA isproposing this level of control becauseEPA and OTAG were not able toidentify any reasonable controlmeasures for sources in this sector.Controls for wildfires, feasiblealternatives for open burning, and


13 If States chose to not seek reductions fromsome smaller sources, then the overall costsestimated for this sector would be expected toincrease.

reasonable cost-effectiveness levels forcontrol of existing residential waterheaters have not yet been identified forthese States. Therefore, EPA believesthat application of Level 0 controls forthis sector is appropriate.

The OTAG recommendations for thenonutility point sector are to reduceemissions from medium- and large-sizedunits in a manner equitable with utilitycontrols. Specifically, OTAGrecommended that large nonutilitysources should meet approximately 70percent reduction and medium-sizedsources should meet RACT if utilitiesare subject to the 0.15 lb/MMBtu utilitylimit.

As discussed in section III.B.2., EPAis proposing to apply the OTAGrecommendations. The EPA believesthat these are reasonable levels ofcontrols for these sources for the reasonsoutlined in section III.B.2.

For purposes of the budgetcalculation, EPA believes that it isreasonable to not calculate reductionsfrom sources with emissions less than 1ton per day. The OTAG’srecommendation to focus controls onthe large sources rather than all sourcesfor purposes of establishing the budgetis a reasonable approach from anadministrative and data availabilityperspective and does not precludeStates from eventually adopting controlson other sizes or categories of sources asan alternative way of meeting theirbudgets. 13 In addition, emissions datafor the smaller nonutility sources havemore uncertainty, especially source sizeand utilization data which are importantin making a budget calculation. Asdescribed in section III.B.2, EPA’s costanalysis does not key on source sizes;rather, it is a least cost approach thatconsiders small, medium and largesources in determining the overall costof the sector budget. Further, controlson smaller sources are frequently lesscost effective than the same controls onlarger sources. It should also be notedthat the 1 ton per day cutoff fornonutility sources approximatelycorresponds to the 25 MWe cutoff forutility sources. The EPA solicitscomment on: (1) whether sources withNOX emissions less than 1 ton per dayshould be included in the nonutilitycomponent of each State’s budget, and(2) sources of emissions and utilizationdata for sources with NOX emissionsless than 1 ton per day.

Other approaches to calculating thenonutility point source budget

component were considered, includinga combined Level 2 for large sourcesand Level 1 for smaller sources, an 80percent reduction from large sourceswith Level 1 for the smaller sources (seeTable III–2), and Level 1 or Level 2applied across the entire sector. A Level1 approach across the entire sector hasa relatively low cost effectiveness (lessthan $1000 per ton) and is not asequitable as the OTAGrecommendations, considering thereductions calculated for the electricutility sector and the importance of thenonutility point source sector from atotal emissions standpoint. On the otherhand, EPA considered a Level 2approach across the entire sector to beless cost effective and administrativelymore difficult than the OTAGrecommendations. That is, Level 2nonutility costs for some of the smallersources are likely to be higher in somecases than the Level 3 utility costs andthe number of units included in thenonutility point source category is large,creating an administrative burden. Asdiscussed in section II.B.3, anotheralternative approach would be toassume a higher level of control forcombustion units which generateelectricity for purposes internal to aplant. Some of these units may moreappropriately be included with theutility sector emissions, with similarrequired levels of control, since controlsfor these units may be as cost effectiveas utility unit controls. Additionally,certain large industrial combustionsources (e.g., boilers with a heat inputlarger than about 250 MMBtu/hour,used only for steam, not electricitygeneration) may be able to achievelevels of control equal to that of theelectric utility units with comparablecost effectiveness. The EPA solicitscomment on these and other approachesfor calculating the nonutility pointsource budget component.

In applying the proposed controls, theEPA closely approximated but could notprecisely calculate emissions based onthe size of nonutility point sources asdefined by OTAG because the emissionsinventories available do not have thelevel of detail specified in the OTAGrecommendation.

For example:• The OTAG recommendation

separates boilers by size (i.e., less than100 MMBtu, between 100 and 250MMBtu and greater than 250 MMBtu).Available emissions inventory data areincomplete especially for the smallersize boilers.

• The OTAG recommendationseparates stationary reciprocatinginternal combustion engines by size(i.e., less than 4000 horsepower (hp),

between 4000 and 8000 hp, and greaterthan 8000 hp). Available emissionsinventory data generally does notinclude hp capacities.

• The OTAG recommendationseparates gas turbines by less than10,000 hp, between 10,000 and 20,000hp, and greater than 20,000 hp.Available emissions inventory datagenerally do not include hp capacities.

• The OTAG recommendations alsoinclude application of RACT onmedium-sized sources; RACT isgenerally considered equal to Level 1OTAG measures. However, since RACTmay be a case-by-case decision, aprecise forecast of emissions decreasescannot be made.

In order to calculate the proposedbudget components based onapplication to the controls discussedabove, EPA applied 70 percentreduction controls for boilers greaterthan 250 MMBtu/hour and other largesources (see TSD for details). Boiler sizewas determined on an SCC basis (i.e.,the same level of control was applied toall boilers within a specific SCCregardless of the size of individualboilers). In addition, EPA applied RACTcontrols for sources not classed ‘‘large’’and emitting between 1–2 tons per day;these reductions are generally in therange of 25–50 percent emissionsdecrease. Where information on boilersize was not available, EPA assumedthat the source was medium-sized andapplied RACT controls. For othermedium- and large-sized nonutilitysources, EPA applied 70 percentreduction controls where informationon size of sources was available, andRACT controls for the remainingsources (see Budget TSD for details).Due to the lack of data in theinventories, especially for internalcombustion engines and turbines, EPAcould not base a budget calculationprecisely on OTAG’s recommendationof 70 percent reduction for largesources.

The proposed procedures forcalculating seasonal emissions for thesesectors differs from that used forutilities because, unlike utilities, dayspecific emissions are not available foreach day of the season. In general, athree-step process is proposed to obtainsummer season emission totals for thearea and nonutility sectors. First, OTAGemissions reflecting the above controlsare obtained for ‘‘typical’’ summerweekday, Saturday, and Sundayoperating conditions for each sector foreach State. The underlying proceduresand assumptions used for deriving theseemissions are described in the OTAGEmissions Inventory DevelopmentReports (8). Second, the weekday


emissions are multiplied by 109 (thetotal number of weekdays in the periodMay 1 through September 30), and theSaturday and Sunday emissions areeach multiplied by 22 (the total numberof weekends in the 5-month season). Inthe third step, these estimates aresummed for each day-type to get thesummer season total emissions by sectorby State.

c. Summary and Proposed Area andNonutility Point Source BudgetComponents. The resulting proposednonutility point and area budgetcomponents are contained in Table III–7 below along with a comparison fornonutility point sources to the 2007CAA base. The area budget componentsare not compared to the 2007 basebecause no reductions were calculatedfor this budget sector. For the nonutility

point sources, EPA applied controls thatapproximate the OTAGrecommendations. For the area andnonutility sectors, we used the summerweekday, Saturday, and Sundayemissions that were available in theOTAG data base for these control levels.The OTAG growth assumptions wereused for area and nonutility pointsource sectors.

TABLE III–7.—PROPOSED BUDGET COMPONENTS FOR NONUTILITY POINT AND AREA SECTORS

[Tons of NOX per Ozone Season]

State

2007 CAAbase

2007 Budget components Percentreduction

Nonutility point Nonutility point Area Nonutility point

Alabama ............................................................................................................ 47,182 25,131 25,229 47Connecticut ....................................................................................................... 4,732 4,475 4,587 5Delaware ........................................................................................................... 5,205 3,206 1,035 38District of Columbia .......................................................................................... 312 312 741 0Georgia ............................................................................................................. 34,012 20,472 11,901 40Illinois ................................................................................................................ 63,642 39,855 7,270 37Indiana .............................................................................................................. 51,432 35,603 25,545 30Kentucky ........................................................................................................... 18,817 12,258 38,801 35Maryland ........................................................................................................... 6,729 4,825 8,123 28Massachusetts .................................................................................................. 10,683 7,590 10,297 29Michigan ........................................................................................................... 57,190 35,317 28,126 38Missouri ............................................................................................................ 12,248 8,174 6,626 33New Jersey ....................................................................................................... 32,663 26,741 11,388 18New York .......................................................................................................... 19,889 16,930 15,585 15North Carolina .................................................................................................. 32,107 21,113 9,193 34Ohio .................................................................................................................. 50,946 32,799 19,446 36Pennsylvania .................................................................................................... 64,224 59,622 17,103 7Rhode Island .................................................................................................... 328 328 420 0South Carolina .................................................................................................. 34,791 20,097 8,420 42Tennessee ........................................................................................................ 65,051 32,138 11,991 51Virginia .............................................................................................................. 23,333 15,529 25,261 33West Virginia .................................................................................................... 41,510 31,377 4,901 24Wisconsin ......................................................................................................... 21,209 12,269 10,361 42

Total ................................................................................................... 698,235 466,158 302,350 33

5. Proposed Assumptions for HighwayVehicles

a. Affected Entities. The highwayvehicle sector encompasses thosesources that normally operate on roadsand highways. All light-duty cars andtrucks, medium-duty trucks, heavy-dutytrucks, motorcycles, and buses areincluded in this category. NOX

emissions from these sources, includingthe effects of the fuel used to powerthese sources, are included in theestimate of emissions from the highwayvehicle sector. These estimates alsoincorporate the effects of emissioncontrol programs which are intended toreduce emissions from these sources.

b. Methodology Used to Develop theProposed Highway Vehicle BudgetComponent

i. Budget Component DeterminationMethod and Alternatives Considered.The EPA proposes to derive States’highway vehicle budget component by

estimating the State-by-State NOX

emissions from highway vehicles in2007. These estimates were developedby modeling the emissions expected in2007 from all highway vehicles. Theestimates are based on: (1) a projectionfor each State’s number of vehicle-miles-traveled (VMT) by vehiclecategory in 2007, as described in sectionIII.B.5.b.iii; and (2) the estimatedemission rate for each vehicle categoryin 2007, assuming implementation ofthose measures incorporated in existingSIPs, measures already implementedfederally, and those additional measuresexpected to be implemented federally.The additional Federal measuresinclude:

• National Low Emission VehicleStandards

• 2004 Heavy-Duty Engine Standards• Revisions to Emissions Test

Procedure.

These measures either have beenpromulgated in final form or areexpected to have been promulgated bythe time today’s proposal is made final.All of these measures are expected to beimplemented nationwide or in the 49States other than California and hencewould be in effect in those Statesrequired to submit a transport SIP underthis proposal. Since these measureswould be in effect as of 2007, EPAbelieves it is appropriate to reflect theimpact of these measures in 2007 incalculating States’ highway vehiclebudget components and proposes to doso. However, it should be noted that theNLEV program is a voluntary programthat will not take effect until theNortheastern States and the automanufacturers agree to participate.While EPA expects such an agreementto be reached, the Agency acknowledgesthat such an agreement is not certain atthe current time. Should the


14 The Trends report method projects nationalVMT based on a growth rate of about 2% per yearand allocates VMT to States based on CensusBureau forecasts of population levels in each State.

Northeastern States and the automanufacturers fail to agree to implementNLEV, EPA proposes to revise States’highway vehicle budget componentsand overall NOX budgets accordingly.This revision would increase States’NOX budgets. The EPA requestscomment on this proposal.

The EPA proposes not to incorporatein its calculation of the highway vehiclebudget component any benefits fromTier 2 light-duty vehicle standards. TheAgency’s decision to go forward withsuch standards is contingent on thedetermination that such standards arenecessary to achieve air qualityobjectives and can be done so in a cost-effective manner. The EPA is currentlyengaged in an investigation of these andother issues related to Tier 2 standards,and it is premature to assume that suchstandards will be implemented prior to2007. Therefore, EPA cannot at this timemodel the impact of a potential set ofTier 2 standards on emissions fromaffected States in 2007. If suchstandards are promulgated andimplemented prior to 2007, EPAproposes to adjust States’ highwayvehicle budget components and overallNOX budgets accordingly to reflectimplementation of these standards. TheEPA requests comment on this approachfor Tier 2 emission standards.

The EPA proposes to assume fullimplementation of other highwayvehicle emission control programs asrequired by the CAA or contained inexisting SIPs and maintenance plans incalculating each State’s highway vehiclebudget component for the purpose ofestablishing a statewide NOX emissionbudget. This proposal would encompassI/M programs, Federal Phase II RFG,Clean Fuel Fleet programs, and otherprograms intended to reduce NOX

emissions from highway vehicles. TheEPA further proposes to assumecontinued participation in the RFGprogram by the mandatory RFG areasand by those areas which have optedinto the program. The EPA requestscomment on the appropriateness ofthese proposals. In particular, EPArequests comment on whether the extentof the RFG coverage area chosen incalculating the highway vehicle budgetcomponent is appropriate, and onwhether the normally-required NOX

reductions from I/M programs in thoseareas whose section 182 waiverscurrently exempt them from the I/MNOX performance standard should beassumed when calculating Statehighway vehicle budget componentsand overall NOX budgets.

States have the discretion to adoptadditional mobile source controlmeasures as part of their transport SIP

revision in order to meet their NOX

budget or to meet other air qualityobligations. The EPA agrees with OTAGthat States should consider such controlmeasures as RFG, I/M programs, andtransportation control measures beyondthose already included in State SIPs.These measures are applied andimplemented locally rather thannationally, and in some cases theirspecific features are designed locally aswell. The EPA recognizes that Statesand localities have more detailedinformation on which to base anydecision to expand these programsbeyond their current extent than doesEPA. State and local decisions toexpand these programs can be based onthe unique characteristics of local areasand the nature of the ozone challengesthey face. In particular, these programsprovide VOC reductions larger than theNOX reductions they provide, and theOTAG modeling suggests that VOCreductions affect local ozone levels buthave limited impact on downwindozone levels. The EPA believes theseprograms may be attractive to manyStates and localities because they canoffer large reductions in VOC, CO, andtoxics emissions, in addition toreductions in NOX emissions, at arelatively modest cost. Hence Statesmay want to adopt these or other localmeasures to achieve or maintain localozone or CO attainment or to reduceexposure to toxic air pollutants, as wellas to meet their obligations for NOX

reductions to meet their statewide NOX

budget. States which choose to do somay be able to adopt less-stringentcontrols on other sectors while stillmeeting their obligations to reduce NOX

emissions as described in thisrulemaking. For the reasons discussedabove, EPA is not proposing to reducethe budgets to assume further controlsfrom Federal or State motor vehiclemeasures. The NOX reductions alonefrom those measures do not appearsufficiently cost effective in all of theareas that would be subject to reducedbudgets, since for some areas there is noneed for local ozone or CO reductions.

ii. Activity Level Projections andGrowth Considerations. The EPAproposes to use the best availableprojections of State VMT levels in 2007in calculating States’ budgetcomponents for the highway vehiclesector. For the purposes of providingestimates in today’s action, EPA hasused the 2007 projections developed byOTAG. The OTAG projections werebased on actual 1990 VMT levels foreach State, based on State submittals toOTAG where available or on estimatesgenerated by the Highway Performance

Monitoring System (HPMS) otherwise.These base year VMT levels were thenprojected to 2007, using growth ratesagreed to or in some cases supplied bythe State. The EPA proposes to use thestate-specific estimates of VMT growthby vehicle category through 2007, asdeveloped in the OTAG process, incalculating States’ highway vehiclebudget components and overall NOX

budgets. In most cases, States acceptedOTAG-proposed growth estimates equalto those used by the Agency in theOctober 1995 edition of its annualreport, ‘‘National Air Pollutant EmissionTrends’’ (16), although several Statessubmitted (and the OTAG inventoryincorporated) growth estimates thatwere significantly lower than the growthestimates used by the Agency in its 1995Trends report. One State submittedgrowth estimates that were higher thanthe 1995 Trends report growthestimates.

The EPA has considered a number ofoptions to forecast highway VMT levelsin 2007. For today’s proposal, EPA haschosen to use the projected VMT levelsused by OTAG. As discussed above,most of those growth rate estimates wereconsistent with EPA’s estimates in itsTrends report.14 Furthermore, the open,collaborative OTAG process allowedinterested parties to review VMT andVMT growth estimates whenconstructing future year emissionestimates. The EPA encourages eachState subject to today’s action to reviewthe OTAG 1990 VMT levels and VMTgrowth projections again; EPA alsorequests each affected State to reviewthese projections for consistency withother State projections, includingprojections used in SIPs fornonattainment areas. The EPA expectsthat all involved State and localagencies will coordinate and concur onany new VMT growth rate submissions,as should be the case when growth ratesare developed for use in SIP revisionscontaining VMT and emissionsprojections. The EPA proposes toincorporate revised VMT growthprojections received from States duringthe comment period of today’s actioninto its final rule, if appropriatelyexplained and documented.

The EPA further proposes to useactual 1995 VMT levels as the base yearfor the 2007 inventory projections in thefinal rule, rather than continuing to relyon the 1990 VMT levels. The Agencybelieves that the accuracy of projected2007 VMT levels would be improved by


using a more recent base year, since theimpact of any deviation betweenprojected and actual growth ratesthrough 2007 would be reduced. Forthis reason, EPA proposes to use andrequests States to submit VMT data for1995. The EPA requests comment onthis proposal to use actual 1995 VMTlevels as the base year for projecting2007 VMT levels and on the use of 1990VMT levels as the base year in today’saction.

iii. Seasonal/Weekday/WeekendAdjustment. The EPA proposes toproject States’ highway vehicle budgetcomponents during the 2007 ozoneseason based on the actual number ofweekday and weekend days during the2007 ozone season. The OTAGinventory projections, by contrast, werebased on the actual number of weekendand weekday days during the specificozone episodes modeled by OTAG. TheVMT levels on weekdays differ fromVMT levels on weekend days, all otherthings being equal, so it is important touse the proper proportion of weekdaysand weekend days when developinghighway vehicle budget componentsand overall State NOX budgets. SinceStates must demonstrate compliancewith their NOX budgets over the entireozone season in 2007, EPA believes thatthe actual number of weekdays andweekend days during the 2007 ozoneseason should be used to calculatehighway vehicle budget componentsand overall State NOX budgets. The EPArequests comment on this proposal.

The EPA also proposes to base itscalculation of State highway vehiclebudget components and overall NOX

budgets on the average temperatures forthe affected months. The OTAGprojections are based on the actual dailytemperature ranges experienced duringthe episodes modeled by OTAG. Thesetemperature ranges may not berepresentative of the typicaltemperatures experienced during thewhole ozone season as defined intoday’s action, since ozone episodestend to occur during periods of above-average temperature. The estimatedhighway vehicle budget componentspresented in Table III–8 are based on theOTAG temperature ranges and hence arebased on temperatures that may behigher than the average temperaturesexperienced during the 5 ozone seasonmonths. In its final rulemaking, EPAwill revise its highway vehicle budgetcomponents to reflect the averagetemperatures for the affected months.The impact of these temperaturedifferences on highway vehicle budgetcomponents is expected to be modest,because even large differences insummer temperatures have only a

modest effect on estimated NOX

emissions from highway vehicles. Forexample, as temperature goes from 75 to95 degrees Fahrenheit, NOX emissionsincrease by approximately 4 percent.The actual difference between summeraverage and ozone-episode temperatureranges is considerably smaller than 20degrees Fahrenheit, so the size of thetemperature adjustment described abovewould be correspondingly smaller. TheEPA requests comment on theappropriateness of this adjustment andon its proposed use of ozone seasonaverage temperatures instead of ozone-episode temperatures in developingStates’ highway vehicle budgetcomponents and overall NOX budget.

iv. Comparison to OTAGRecommendations. The set ofpresumptive controls modeled by EPAto develop the highway vehicle budgetcomponents and overall NOX budgets isconsistent with the OTAGrecommendations. The OTAGsupported expeditious implementationof Federal measures, including thoselisted above. The OTAG alsorecommended the continued use of RFGin the mandated and current opt-inareas, as reflected in EPA’s proposedmethod for calculating highway vehiclebudget components. The OTAGsupported State flexibility to opt intothe RFG program and encouraged areaswhich face local nonattainment,maintenance, or downwind transportchallenges to opt into the RFG program.The EPA proposes to provide Stateswith such flexibility in devisingstrategies to meet the NOX budgetsoutlined in section III.C. The EPAbelieves that Federal Phase II RFG canprovide cost-effective reductions inozone precursors, since it will reduceemissions of both VOC and NOX. PhaseII RFG can provide VOC and NOX

reductions at a cost of $2600–3500 perton, depending on the amount of fuelaffected by any expansion of theprogram offer. Hence EPA encouragesStates to consider adopting FederalPhase II RFG in areas eligible to opt intothe program as part of their revised SIP.

The OTAG further recommended that‘‘The USEPA should adopt andimplement by rule an appropriate sulfurstandard to further reduce emissionsand assist the vehicle technology/fuelsystem [to] achieve maximum long termperformance.’’ The EPA is engaged in anextensive evaluation of gasoline-basedemission controls as part of its work toevaluate the need for and benefits andcosts of Tier 2 vehicle emissionstandards. This evaluation includes anexamination of the costs and benefits ofgasoline sulfur control. At this time,however, EPA has not yet defined,

quantified, or evaluated the impact ofsulfur control. Furthermore, EPA hasnot at this time decided whether torequire sulfur reductions. Therefore,EPA believes it is not appropriate toassume such reductions whencalculating highway vehicle budgetcomponents or overall NOX budgets. Ifthe Agency does establish gasolinesulfur standards, EPA proposes to adjustState highway vehicle budgetcomponents and overall State NOX

budgets to reflect the emissions impactof such standards on NOX emissionsfrom highway vehicles in 2007. TheEPA requests comment on this proposal.

The OTAG also recommended thatEPA should evaluate the potential forreformulation of diesel fuel for reducingNOX emissions from highway andnonroad diesel engines. The EPA isengaged in an examination of the needfor and potential benefits of diesel fuelreformulation as part of its assessmentof the feasibility of its proposed 2004heavy-duty highway vehicle standards.At the present time, however, EPA doesnot have sufficient information toadequately quantify the potential ofdiesel fuel reformulation to reduce NOX

emissions or to determine the costs ofvarious reformulation strategies. HenceEPA has not incorporated any emissionreductions from diesel fuelreformulation in its calculation ofhighway vehicle budget components oroverall NOX budgets. The EPA willcontinue to evaluate the potential ofdiesel fuel reformulation to reduce NOX

emissions and enable the properfunctioning of engine-based emissioncontrols through the collaborativeprocess developed as a result of the1995 Statement of Principles. If EPAdoes promulgate requirements toreformulate diesel fuel, EPA proposes torevise at that time States’ highwayvehicle budget components and overallNOX budgets to reflect the projectedimpact of the required diesel fuelreformulation on NOX emission fromhighway vehicles.

The OTAG called on the States toadopt inspection and maintenanceprograms where required by the CAA.This recommendation is reflected inEPA’s proposed method of calculatingthe highway vehicle emissions, asdiscussed above. The OTAG also calledon the States to consider expanding I/M programs to urbanized areas ofgreater than 500,000 population in the‘‘fine grid’’ portion of the OTAG region.The EPA believes that properlydesigned and operated I/M programs area practicable and cost-effective means ofreducing ozone precursors. Theseprograms provide VOC reductions aslarge or larger than the NOX reductions


they provide, while the OTAG modelingsuggests that VOC reductions affectlocal ozone levels but have limitedimpact on downwind ozone levels.Therefore, while EPA recognizes thatmany of the States subject to today’sproposal have already implemented orplan to implement I/M programs, andwhile EPA encourages the States toconsider extending I/M programs inother areas to reduce ozone precursorsas part of their attainment andmaintenance strategy, EPA proposes not

to assume expansion of currently-required I/M programs in calculatingStates’ highway vehicle budgetcomponents or overall NOX budgets.The EPA requests comment on thisproposal. Notwithstanding thisproposal, because I/M programs causereductions in NOX emissions implicatedin ozone transport, EPA encourages theStates to consider implementingeffective I/M programs in other areas aspart of their transport SIP.

c. Summary and Proposed HighwayVehicle Budget Components. Thehighway vehicle budget componentspresented in Table III–8 were developedby evaluating the emissions that wouldresult in 2007 when existing CAArequirements are met and additionalFederal measures are implemented.These estimates are based on the 1990VMT levels and growth rates suppliedto OTAG by the States.

TABLE III–8. BUDGET COMPONENTS FOR HIGHWAY VEHICLES


State 2007 CAAbase

Proposedbudget

component

Percentreduction

Alabama ....................................................................................................................................... 61,205 56,601 8Connecticut ................................................................................................................................... 23,446 17,392 26Delaware ...................................................................................................................................... 8,867 8,449 5District of Columbia ...................................................................................................................... 3,081 2,267 26Georgia ......................................................................................................................................... 88,363 77,660 12Illinois ............................................................................................................................................ 91,656 77,690 15Indiana .......................................................................................................................................... 72,294 66,684 8Kentucky ....................................................................................................................................... 49,789 46,258 7Maryland ....................................................................................................................................... 39,941 28,620 28Massachusetts .............................................................................................................................. 35,308 23,116 35Michigan ....................................................................................................................................... 91,449 81,453 11Missouri ........................................................................................................................................ 61,778 55,056 11New Jersey ................................................................................................................................... 55,783 39,376 29New York ...................................................................................................................................... 114,234 94,068 18North Carolina .............................................................................................................................. 80,955 73,056 10Ohio .............................................................................................................................................. 104,422 92,549 11Pennsylvania ................................................................................................................................ 81,805 73,176 11Rhode Island ................................................................................................................................ 7,566 5,701 25South Carolina .............................................................................................................................. 53,566 49,503 8Tennessee .................................................................................................................................... 72,907 67,662 7Virginia .......................................................................................................................................... 88,792 79,848 10West Virginia ................................................................................................................................ 23,267 21,641 7Wisconsin ..................................................................................................................................... 46,390 41,651 10

Total ................................................................................................................................... 1,356,864 1,179,477 13

d. Conformity. The CAA section 176(c) requires federally supportedactivities to conform to the purpose ofthe SIP. Specifically, the Federalgovernment cannot support an activitythat causes or worsens air qualityviolations or delays attainment.Conformity applies to nonattainmentand maintenance areas.

The CAA establishes several morespecific requirements regarding howconformity of Federal highway andtransit activities must be determined.For example, the emissions expectedfrom the implementation oftransportation plans and programs mustbe consistent with estimates ofemissions from highway vehicles andnecessary emissions reductionscontained in the SIP. The EPA haspromulgated regulations (40 CFR parts51 and 93) to implement the general and

transportation-related conformityrequirements.

The EPA proposes that neither thehighway vehicle budget components northe overall NOX budgets proposed inthis rulemaking change the existingconformity process or existing SIPs’motor vehicle emissions budgets underthe conformity rule. The EPA does notbelieve that Federal agencies orMetropolitan Planning Organizations(MPOs) operating in States subject totoday’s proposal must demonstrateconformity to the proposed budgets orthe highway vehicle budget componentlevels used to calculate the budgets.Whereas the conformity provisions insection 176(c) of the CAA apply tononattainment and maintenance areas,the States’ emission budgets applystatewide. Without greater geographicdisaggregation in the SIP, Federalagencies and MPOs will not be able to

determine consistency with theemission estimates in the transport SIPrevision being requested in today’sproposal. Furthermore, EPA does notbelieve that consistency with thestatewide emissions estimates intransport SIPs can be used to determinewhether or not a transportation or otherFederal activity will cause or worsenlocal air quality violations. Thestatewide budget does not represent thelevel of emissions necessary forattainment or a reasonable furtherprogress milestone. In contrast,attainment demonstrations, 15 percentSIPs, post-1996 rate-of-progress, andmaintenance plans—SIPs to which EPArequires conformity—do contain motorvehicle and other emissions estimateson which the attainment, maintenance,or progress demonstration depends.


6. Proposed Assumptions for NonroadSources

a. Affected Entities. The nonroadsector encompasses those mobilesources that normally do not operate onroads and highways. This sectorincludes recreational and commercialmarine engines; small engines such asthose used to power snowmobiles,chainsaws, or lawn and gardenequipment; larger nonroad engines suchas those used to power agriculturalequipment, construction equipment,industrial/commercial equipment(forklifts, pumps, compressors,generator sets), and mining equipment;aircraft, and locomotives. Emissionsfrom these sources, including the effectsof the fuel used to power these sources,would be included in the estimate ofemissions from the nonroad sector.These estimates would also incorporatethe effect of emission control programswhich are intended to reduce emissionsfrom these sources.

b. Methodology Used to Determine theProposed Nonroad Budget Component.

i. Budget Component DeterminationMethod and Alternatives Considered.The EPA proposes that the States’nonroad budget component be derivedby estimating the State-by-State NOX

emissions from nonroad engines in2007. These estimates would bedeveloped by modeling the emissionsexpected in 2007 from all nonroadengines. The estimates would be basedon: (1) a projection for each State’snumber of engines of each type andapplication in 2007; (2) a projection ofthe level of activity for each type andapplication of nonroad engine in 2007;and (3) the estimated emission rate foreach engine type and application in2007, assuming implementation of thosemeasures incorporated in existing SIPs,measures already implementedfederally, and those additional measuresexpected to be implemented federally.The additional Federal measuresinclude:

• Federal Small Engine Standards,Phase II.

• Federal Marine Engine Standards(for diesels > 50 horsepower).

• Federal Locomotive Standards.• 1997 Proposed Nonroad Diesel

Engine Standards.All of these measures either have been

proposed or are expected to be proposedin the near future and are sufficientlywell-defined to model their emissionimpacts in 2007. These measures areexpected to be implemented nationwideand hence would be in effect in thoseStates required to submit a SIP underthis proposal. Since these measureswould be in effect as of 2007, EPA

believes it is appropriate to reflect theimpact of these measures in 2007 incalculating States’ nonroad budgetcomponents and proposes to do so.

States have the discretion to adoptadditional nonroad control measures aspart of their transport SIP revision inorder to meet their NOX budget or tomeet other air quality obligations. TheEPA agrees with OTAG that Statesshould consider such control measuresas RFG, scrappage programs, andactivity level control measures beyondthose already included in State SIPs.These measures are applied andimplemented locally rather thannationally, and in some cases theirspecific features are designed locally aswell. The EPA recognizes that Statesand localities have more detailedinformation on which to base anydecision to expand these programsbeyond their current extent than doesEPA. State and local decisions toexpand these programs can be based onthe unique characteristics of local areasand the nature of the ozone challengesthey face. In particular, some of theseprograms tend to provide VOCreductions that are larger than the NOX

reductions they provide, along withsignificant CO, toxics, and particulatematter reductions. The OTAG modelingsuggests that VOC reductions affectlocal ozone levels but have limitedimpact on downwind ozone levels.Hence States may want to adopt thesemeasures to help achieve or maintainlocal attainment, as well as to help meettheir obligation to mitigate transport.States which choose to do so may beable to adopt less-stringent controls onother sectors while still complying withtheir overall budget.

ii. Activity Level Projections andGrowth Considerations. The EPAproposes to use the best availableprojections of State nonroad activitylevels in 2007 in calculating States’budget components for the nonroadsector. For the purposes of providingestimates in today’s action, EPA hasused the 2007 projections developed byOTAG. The OTAG projections werebased primarily on estimates of actual1990 nonroad activity levels found inthe October 1995 edition of EPA’sannual report, ‘‘National Air PollutantEmission Trends.’’ Several Statessubmitted estimates of their 1990nonroad activity levels that differedfrom these estimates. The OTAG growthrates were based on growth projectionsissued by the Bureau of EconomicAffairs and hence were consistent withthose used by the Agency in its October1995 ‘‘Trends’’ report. At the presenttime, EPA considers the growthestimates to be reasonable; however, the

Agency requests comment on itsproposal to use the OTAG growthprojections of nonroad activity levels incalculating the nonroad budgetcomponents and overall NOX budgetsfor those States subject to today’sproposal. The basis of the OTAG growthprojections is explained in greater detailin OTAG’s Emission InventoryDevelopment Report, Volume I, pages11–13.

The EPA encourages each Statesubject to today’s proposal to review theOTAG nonroad growth projectionsagain; EPA also requests each affectedState to review these projections forconsistency with other State projections,including projections used in SIPs fornonattainment areas. The EPA expectsthat all involved State and localagencies will coordinate and concur onany new nonroad growth ratesubmissions, as should be the casewhen growth rates are developed for usein SIP revisions containing nonroadactivity level and emissions projections.The EPA proposes to incorporaterevised nonroad growth projectionsreceived from States during thecomment period of today’s proposal intoits final rule, if appropriately explainedand documented. The EPA requestscomment on these proposals.

The EPA further proposes to useestimated historical 1995 nonroadactivity levels as the base year for the2007 inventory projections in the finalrule, rather than continuing to rely onthe 1990 nonroad activity levels. TheAgency believes that the accuracy ofprojected 2007 nonroad activity levelswould be improved by using a morerecent base year, since the impact of anydeviation between projected and actualgrowth rates through 2007 would bereduced. For this reason, EPA proposesto use its 1997 ‘‘Trends’’ estimate of1995 nonroad activity levels in its finalrulemaking and requests comment onthis proposal. The EPA also requestscomment on its proposal to use actual1995 nonroad activity levels as the baseyear for projecting 2007 nonroadactivity levels and on the use of 1990nonroad activity levels as the base yearin today’s action.

iii. Seasonal/Weekday/WeekendAdjustment. The EPA proposes toproject States’ nonroad budgetcomponents during the 2007 ozoneseason based on the actual number ofweekday and weekend days during the2007 ozone season. The OTAGinventory projections, by contrast, werebased on the actual number of weekendand weekday days during the specificozone episodes modeled by OTAG.Nonroad activity levels on weekdaysdiffer from levels on weekend days, all


other things being equal, so it isimportant to use the proper proportionof weekdays and weekend days whendeveloping nonroad budget componentlevels and overall State NOX budgets.Since States must demonstratecompliance with their NOX budgets overthe entire ozone season in 2007, EPAbelieves that the actual number ofweekdays and weekend days during the2007 ozone season should be used tocalculate budget components andoverall State NOX budgets. The EPArequests comment on this proposal.

The EPA also proposes to base itscalculation of the State nonroad budgetcomponents and overall NOX budgetson the average temperatures for theaffected months. The OTAG projectionsare based on the actual dailytemperature ranges experienced duringthe episodes modeled by OTAG. Thesetemperature ranges may not berepresentative of the typicaltemperatures experienced during thewhole ozone season as defined intoday’s proposal, since ozone episodestend to occur during periods of above-average temperature. The estimatednonroad emissions presented in TableIII–9 are based on the OTAGtemperature ranges and hence are basedon temperatures that may be higher thanthe average temperatures experiencedduring the five ozone season months. Inits final rulemaking, EPA will revise itsnonroad budget components and overallNOX budgets to reflect the averagetemperatures for the affected months.The impact of these temperaturedifferences on nonroad budgetcomponents and overall NOX budgets isexpected to be modest, because evenlarge differences in summertemperatures have only a modest effecton estimated nonroad NOX emissions.The EPA requests comment on theappropriateness of this adjustment andon its proposed use of ozone seasonaverage temperatures instead of ozone-episode temperatures in developing

States’ nonroad budget components andoverall NOX budget.

iv. Comparison to OTAGRecommendations. The set ofpresumptive controls modeled by EPAto develop the nonroad sector budgetcomponents for each State is consistentwith the OTAG recommendations. TheOTAG supported expeditiousimplementation of Federal measures,including those listed above. The OTAGalso recommended the continued use ofRFG in the mandated and current opt-in areas, as reflected in EPA’s proposedmethod for calculating the nonroadbudget components. As discussed insection III.B.5, OTAG supported Stateflexibility to opt into the RFG programand encouraged areas which face localnonattainment, maintenance, ordownwind transport challenges to optinto the RFG program. Although currentEPA guidance indicates that Phase IIRFG will not reduce NOX emissionsfrom nonroad engines, Phase II RFG willoffer significant VOC emissionreduction benefits from nonroadengines. As discussed in section III.B.5,EPA encourages States to consideradopting Federal Phase II RFG in areaseligible to opt into the program as partof their revised SIP.

Current EPA guidance also indicatesthat changes in fuel sulfur levels,including any changes that may resultfrom EPA’s Tier 2 study, would notaffect NOX emissions from gasoline-powered nonroad equipment since suchequipment is not equipped withcatalytic converters. Hence EPAproposes not to change States’ nonroadbudget components if EPA shouldpromulgate sulfur standards as a resultof the Tier 2 study or any other EPAanalysis, unless nonroad enginesequipped with catalytic convertersbegin to be introduced into the U.S.marketplace. The EPA requestscomment on this proposal.

As discussed in section III.B.5, OTAGrecommended that EPA should evaluate

the potential for reformulation of dieselfuel for reducing NOX emissions fromboth highway and nonroad dieselengines. The EPA is engaged in anexamination of the need for andpotential benefits of diesel fuelreformulation as part of its assessmentof the feasibility of its proposed 2004heavy-duty highway vehicle emissionstandards but has not as of this writingcompleted its examination.Furthermore, EPA does not havesufficient information at the presenttime to quantify adequately thepotential of diesel fuel reformulation toreduce NOX emissions from nonroaddiesel engines or to determine the costsof various reformulation strategies. Forthese reasons, EPA has not incorporatedany emission reductions from dieselfuel reformulation in its calculation ofStates’ nonroad budget components. IfEPA does promulgate requirements toreformulate diesel fuel, EPA willevaluate whether additional research todetermine the impact of diesel fuelreformulation on NOX emissions fromnonroad engines is needed. The EPAproposes to defer any consideration ofrevisions to States’ nonroad sectorbudget components and overall NOX

budgets to reflect the impact of dieselfuel reformulation on NOX emissionfrom nonroad engines until such time asdiesel fuel reformulation standards, andthe effect of those standards on nonroadengine NOX emissions, have beenadequately defined. The EPA requestscomment on this proposal.

c. Summary and Proposed NonroadBudget Components. The nonroadmobile sources sector budgetcomponents presented in Table III–9were developed by evaluating theemissions that would result in 2007when existing CAA requirements aremet and additional Federal measures areimplemented. These estimates are basedon the 1990 activity levels and growthrates supplied to OTAG by the States.

TABLE III–9.—BUDGET COMPONENTS FOR NONROAD SOURCES


State 2007 CAAbase

Proposedbudget com-

ponent

Percent reduc-tion

Alabama ....................................................................................................................................... 21,742 18,727 14Connecticut ................................................................................................................................... 11,679 9,581 18Delaware ...................................................................................................................................... 4,663 4,262 9District of Columbia ...................................................................................................................... 3,609 3,582 1Georgia ......................................................................................................................................... 27,151 22,714 16Illinois ............................................................................................................................................ 66,122 56,429 15Indiana .......................................................................................................................................... 30,489 27,112 11Kentucky ....................................................................................................................................... 25,327 22,530 11Maryland ....................................................................................................................................... 21,717 18,062 17Massachusetts .............................................................................................................................. 22,865 19,305 16Michigan ....................................................................................................................................... 29,005 24,245 16


TABLE III–9.—BUDGET COMPONENTS FOR NONROAD SOURCES—Continued[Tons of NOX per Ozone Season]

State 2007 CAAbase

Proposedbudget com-

ponent

Percent reduc-tion

Missouri ........................................................................................................................................ 22,582 19,102 15New Jersey ................................................................................................................................... 25,150 21,723 14New York ...................................................................................................................................... 35,934 30,018 16North Carolina .............................................................................................................................. 22,867 18,898 17Ohio .............................................................................................................................................. 46,214 42,032 9Pennsylvania ................................................................................................................................ 33,707 29,176 13Rhode Island ................................................................................................................................ 2,511 2,074 17South Carolina .............................................................................................................................. 15,446 12,831 17Tennessee .................................................................................................................................... 54,710 47,065 14Virginia .......................................................................................................................................... 29,160 25,357 13West Virginia ................................................................................................................................ 10,966 10,048 8Wisconsin ..................................................................................................................................... 19,208 15,145 21

Total ................................................................................................................................... 582,824 500,018 14

C. State-by-State Emissions Budgets

The EPA is proposing a statewideemission budget for the year 2007 foreach State covered by today’s action.The proposed statewide budgets werecalculated by summing the budgetcomponents which were calculated asdescribed above. Budget componentswere calculated for the following fivesectors: electric utility, nonutility point,area, nonroad engines, and highwayvehicles.

The proposed overall budgets to beachieved by 2007 include reductionsfrom all Federal programs that wouldcontinue to result in emissionreductions from the compliance date forthe State-adopted rules (betweenSeptember 2002 and September 2004that EPA establishes in its finalrulemaking) to 2007. In 2007, EPA plansto begin a reassessment of transport. Atthat time, EPA will determine how anynew data and tools (such as new airquality models) should be incorporated.

The portion of the budget over whichStates have control (i.e., the non-Federalportion) would have to be implementedbetween September 2002 and September2004. These concepts are fullydiscussed in section V, SIP Revisionsand Approvability Criteria, of thisrulemaking.

The proposed State-by-State budgetsare shown in Table III–10 below. Thistable compares the proposed budgets tothe 2007 CAA emissions which were thestarting point for the calculation.

TABLE III–10.—PROPOSED SEASONAL NOX EMISSIONS BUDGET FOR STATES MAKING A SIGNIFICANT CONTRIBUTION TODOWNWIND OZONE NONATTAINMENT


State 2007 CAAemissions

Proposed2007

budget

Percentreduction

Alabama ................................................................................................................................. 237,062 152,634 36Connecticut ............................................................................................................................. 50,159 39,445 21Delaware ................................................................................................................................ 30,671 21,342 28District of Columbia ................................................................................................................ 8,128 7,054 9Georgia ................................................................................................................................... 254,373 162,905 35Illinois ...................................................................................................................................... 343,742 213,077 38Indiana .................................................................................................................................... 357,647 203,734 100Kentucky ................................................................................................................................. 261,422 155,667 40Maryland ................................................................................................................................. 111,841 70,994 36Massachusetts ........................................................................................................................ 107,437 73,263 32Michigan ................................................................................................................................. 287,827 194,542 32Missouri .................................................................................................................................. 195,547 111,890 43New Jersey ............................................................................................................................. 139,537 104,270 25New York ................................................................................................................................ 225,281 181,254 19North Carolina ........................................................................................................................ 228,395 149,803 34Ohio ........................................................................................................................................ 406,785 233,584 43Pennsylvania .......................................................................................................................... 322,034 218,671 32Rhode Island .......................................................................................................................... 11,599 9,429 19South Carolina ........................................................................................................................ 155,586 105,941 31Tennessee .............................................................................................................................. 276,653 178,173 35Virginia .................................................................................................................................... 212,265 162,879 21West Virginia .......................................................................................................................... 164,362 91,273 44Wisconsin ............................................................................................................................... 148,171 95,181 35

Total ............................................................................................................................. 334,266,508,374 2,937,005 35


D. Recalculation of Budgets

The EPA is proposing statewideemissions budgets calculated asdescribed above. The EPA specificallyinvites public comment on the overallapproach as well as the individualelements that were used in thesecalculations (e.g., emission factors,source-specific data, and, growthassumptions). The EPA is proposingthat the same elements and assumptionsused in the EPA budget calculations beused by the States as they developrevisions to their SIPs in response totoday’s proposal. However, EPArecognizes that changes to theseindividual elements may be warranted.If changes to any of these elements areappropriate, based on commentsreceived, EPA proposes recalculatingthe budgets with the revised data, asdescribed below. The intention of thisprocedure is to take into account newinformation that would replace lessaccurate data previously relied upon.That is, EPA intends to continue to usethe best information available as well asto assure that the States carry out theirplans to reduce emissions so that, in theend, the transport of ozone and ozoneprecursors is decreased.

For example, for nonutility pointsources, OTAG recommended thatRACT should be considered forindividual medium sized nonutilitypoint sources. The EPA proposedbudget calculations generally follow theOTAG recommendations. Because thedefinition of RACT may vary fromsource-to-source, it is not possible toprecisely forecast emissions reductionsdue to RACT on a source-specific basis.States, however, may have source-specific information useful indetermining RACT for sources in theirStates and may, therefore, provide moreprecise information. With respect to thelarge nonutility point sources, missingdata in the OTAG emissions inventoriesprecludes EPA from precisely followingthe recommended definitions of largesources. Thus, States may provide moreprecise information for EPA to use inthe budget calculations. In such cases,EPA is proposing to recalculate thebudgets to take into account the betterdata. New data should be submitted bythe end of the public comment periodso that recalculation would occur priorto final rulemaking on this proposal; ifany additional data become availableafter EPA’s final rulemaking action,such data could be considered prior toState submittal of revised SIPs. The EPAis soliciting comment on this approach.

Similarly, with respect to growthassumptions, States should use the samegrowth rates EPA used to calculate the

proposed budgets, unless betterinformation indicates that the growthassumptions should be revised. Newdata should be submitted by the end ofthe public comment period so thatrecalculation would occur prior to finalrulemaking on this proposal; if anyadditional data become available afterEPA’s final rulemaking action, such datacould be considered prior to Statesubmittal of revised SIPs. Changes ingrowth that are the result of clearlyidentified control strategies which canbe shown to provide real, permanent,and quantifiable changes in growth,such as programs to reduce VMT, mayalso be creditable toward meeting the2007 budget. The EPA is solicitingcomment on this approach.

From time to time, EPA updates itsmodels and inventory estimates toreflect new information. As modelschange, EPA recognizes that projectedemission levels such as those used todevelop the overall State NOX budgetsand sector-specific budget componentsproposed in today’s action may change.Furthermore, EPA recognizes that a setof control strategies which an earliermodel projects to result in a given levelof emissions may be estimated to resultin a greater or lesser level of emissions,when evaluated using a newer model,both in terms of absolute emissionlevels and the level of emissions relativeto some other set of control strategies.Similar to the discussion above onsource-specific data and growthassumptions, States should use the samemodels and inventories EPA used tocalculate the proposed budgets, unlessbetter information indicates that theyshould be revised. Changes that are theresult of changes in EPA models and/orinventories may lead to an upward ordownward recalculation of the budgetprior to 2007. New data should besubmitted by the end of the publiccomment period so that recalculationwould occur prior to final rulemakingon this proposal; if any additional databecome available after EPA’s finalrulemaking action, such data could beconsidered prior to State submittal ofrevised SIPs. The EPA requestscomment on whether the State NOX

budgets and budget components forspecific sectors should be revised whenEPA emission and inventory modelschange and on whether States’ SIPrevisions in response to today’s actionshould be revised. The EPA expects toaddress this issue through the processdescribed in section V, SIP Revisionsand Approvability Criteria, to define thereporting and implementationrequirements for today’s action.

Finally, it should be noted that it ispossible that EPA may introduce

additional Federal measures after Stateemission budgets are defined but before2007. As discussed in this rulemaking,EPA is proposing to base State NOX

budgets on a calculation of the NOX

emissions that would result in eachaffected State in 2007 assuming theimplementation of a set of reasonablecontrol measures. Any additionalFederal measures beyond thosedescribed in today’s action would beimplemented regardless of State actionto meet its transport SIP obligations.The EPA considered two approaches inthis instance: one which would, ineffect, provide emissions reductioncredit to the State and one that does not.In the first case, one could argue thatreal emissions reductions result fromthe new Federal measures and,therefore, the State could receive creditsfor these reductions and implement asmaller portion of its planned emissionreductions. In the second approach, theState would be required to continue toimplement the measures in its revisedSIP because those measures continue tobe considered reasonable controlmeasures and all reasonable measuresare needed to mitigate transport. TheEPA believes the latter approach is moreconsistent with the framework of thisproposal. However, EPA requestscomment on both of these approaches.

As noted, EPA is proposing to allowrecalculation of NOX budgets as newinformation becomes available (e.g.,changes in response to the promulgationof additional Federal standardscontrolling NOX, changes in EPAemission and inventory models, changesadopted in SIPs in any of the underlyingelements or assumptions used tocalculate the State NOX budget, or lessthan full implementation of the NLEVrule). The EPA requests comments onwhether State NOX budgets and budgetcomponents for specific sectors shouldbe revised in these cases and whetherStates’ SIP revisions in response totoday’s action should be revised eitherat the request of EPA or upon theinitiation of a State.

IV. Implementation of Revised AirQuality Standards

A. IntroductionOn July 16, 1997, President Clinton

issued a directive to the Administratorof EPA on implementation of therevised air quality standards for ozoneand particulate matter. In the directive,the President laid out a plan for howthese standards are to be implemented.A central element in the directive is theincentive it provides States to act andsubmit control strategy SIPs early inexchange for which many areas will


15 Appendix E contains a description of thecontrols applied in run 5.

16 Appendix E contains a description of thecontrols applied in Run 5.

need little or no additional new localemission reductions beyond thosereductions that will be achieved throughthe regional control strategy. Thisapproach avoids additional burdensassociated with respect to the beneficialozone control measures already underway, while at the same time achievingpublic health protection earlier.

The Presidential directive waspublished in the Federal Register onJuly 18, 1997 (62 FR 38421). The partsof the directive’s implementation planrelevant to the regional NOX reductionstrategy proposed in this rulemaking aredescribed here.

B. BackgroundFollowing promulgation of a revised

NAAQS, section 107(d)(1) the CAAprovides up to 3 years for Stategovernors to recommend and the EPA todesignate areas according to their mostrecent air quality. In addition, undersection 172(b) of the CAA, the Stateswill have up to 3 years from anonattainment designation to developand submit SIPs to provide forattainment of the new standard. TheEPA anticipates that it will need themaximum period allowed under theCAA to designate areas for the 8-hourstandard. Thus, EPA will designateareas by July of 2000. Under the Act,States, therefore, would need to submittheir nonattainment SIPs by 2003.Section 172(a) of the CAA then allowsup to 10 years plus two 1-yearextensions from the date of designationfor areas to attain the revised NAAQS.

C. Implementation PolicyThe implementation plan in the

Presidential Directive has several goals.Three of these goals are especiallyrelevant for the NOX reduction strategyproposed in this rulemaking:

• Reward State and localgovernments and businesses that takeearly action to reduce air pollutionlevels through cost-effective approaches.

• Respond to the fact that pollutioncan travel hundreds of miles and crossmany State lines.

• Minimize planning and regulatoryburdens for State and local governmentsand businesses where air qualityproblems are regional in nature.

To achieve these goals, theimplementation plan includes a policyfor areas that attain the 1-hour standardbut not the new 8-hour standard inwhich EPA will follow a flexibleimplementation approach thatencourages cleaner air sooner, respondsto the fact that ozone is a regional aswell as local problem, and eliminatesunnecessary planning and regulatoryburdens for State and local

governments. A primary element of thepolicy will be the establishment undersection 172(a)(1) of the CAA of a special‘‘transitional’’ classification for areasthat participate in the NOX regionalstrategy proposed in this rulemakingand/or that opt to submit early plansaddressing the new 8-hour standard.Because many areas will need little orno additional new local emissionreductions to reach attainment, beyondthose reductions that will be achievedthrough the regional control strategy,and will come into attainment earlierthan otherwise required, the EPA willexercise its discretion under the law toeliminate unnecessary local planningrequirements for such areas. The EPAwill revise its rules for new sourcereview (NSR) and conformity so thatStates will be able to comply with onlyminor revisions to their existingprograms in areas classified astransitional. During this rulemaking,EPA will also reexamine the NSRrequirements applicable to existingnonattainment areas in order to dealwith issues of fairness among existingand new nonattainment areas. Thetransitional classification will beavailable for any area attaining the 1-hour standard but not attaining the 8-hour standard as of the time EPApromulgates designations for the 8-hourstandard.

Based on the Agency’s review of thelatest OTAG modeling, a regionalapproach, coupled with theimplementation of other alreadyexisting State and Federal CAArequirements, will allow the vastmajority of areas that currently meet the1-hour standard but would nototherwise meet the new 8-hour standardto achieve healthful air quality withoutadditional local controls. Of the 96 newcounties in the 22-State plus DC region,92 are projected to come into attainmentas result of the regional NOX reductionsincluded in the OTAG Run 5 modelingrun.15 A new county is defined as acounty that violates the 8-hour standardbut not the 1-hour standard and is notlocated in an area for the 1-hourstandard designated nonattainment as ofJuly 1997. (In the docket to thisrulemaking is a table with associateddocumentation in which EPA lists these96 new counties in the 22-State plus DCregion with an indication of whether thecounty is projected to attain the 8-hourozone standard based on the OTAG Run5 modeling run.)

This county information should beunderstood with two caveats. First, thislist of counties is based on air quality

data from 1993–95. The data from thisperiod will not be the basis fornonattainment area designations for the8-hour ozone standard. Thosedesignations will be made in the 2000time frame and will be based on themost recent air quality data available atthat time (1997–1999). Therefore, whileEPA expects that the vast majority ofnew counties will attain as a result ofthe NOX regional control strategy, thenumber of new counties may be more orless than the number indicated above.The EPA is also currently updating thislist based on more current air qualitydata which will be included in thedocket to the final rule.

Second, the estimate of whichcounties will attain the 8-hour standardis based on the specific assumptionsmade by the OTAG in Run 5. Becausethe proposed budgets are similar but notidentical to those contained in Run 5,the estimate may change when this ruleis final and implemented. In addition,some of the assumptions used tocalculate the proposed budgets maychange in response to comments EPAmay receive on various portions of thisrulemaking. Therefore, the estimate ofwhich areas will attain the standardsthrough the final regional NOX strategymay be higher or lower than the numberindicated above. In addition, areas inthe region covered by the proposed NOX

reduction strategy in this rulemakingthat would exceed the new standardafter the adoption of the regionalstrategy, including areas that do notmeet the current 1-hour standard, willbenefit as well because the regional NOX

program will reduce the extent ofadditional local measures needed toachieve the 8-hour standard. In manycases these regional reductions may beadequate to meet CAA progressrequirements for a number of years,allowing areas to defer additional localcontrols. In the 22-State plus DC region,of the 124 counties that violate the 8-hour standard which are located in anarea designated nonattainment for the 1-hour standard as of July 1997, 95 areprojected to come into attainment of the8-hour standard as a result of OTAGRun 5 regional NOX reductions.16 Thecaveats noted above for new countiesalso apply to the information presentedhere. (In the docket to this rulemakingis a table with associated documentationin which EPA lists these 124 counties inthe 22-State plus DC region, includingan indication of whether the area isprojected to attain the 8-hour ozonestandard as a result of regional NOX


reductions included in the OTAG Run5 modeling run.)

To determine eligibility for thetransitional area classification, ozoneareas will follow the approachesdescribed below based on their status.

1. Areas Eligible for the TransitionalClassification

a. Areas attaining the 1-hourstandard, but not attaining the 8-hourstandard, that would attain the 8-hourstandard through the implementation ofthe regional NOX transport strategy forthe East. Based on the OTAG analyses,areas in the region covered by thisproposal that can reach attainmentthrough implementation of the regionaltransport strategy outlined in thisrulemaking would not be required toadopt and implement additional localmeasures.

When EPA designates these areasunder section 107(d), it will place themin the new transitional classification ifthey would attain the standard throughimplementation of the regional transportstrategy and are in a State that by 2000submits an implementation plan thatincludes control measures to achievethe emission reductions required by thisproposed rule for States in the regioncovered by this proposed rule. This is 3years earlier than an attainment SIPwould otherwise be required. The EPAanticipates that it will be able todetermine whether such areas willattain based on the OTAG and otherregional modeling and that noadditional local modeling would berequired.

In addition to areas covered by thisproposed rule which could receive thetransitional classification, areas in theOTAG region not required to revise theirSIPs in this rulemaking because they donot significantly contribute to transportmay be able to receive the transitionalclassification as well. An area in theState could be eligible for thetransitional area classification bysubmitting a SIP attainmentdemonstration in 2000 in which theState adopts NOX emissions decreasessimilar to those EPA proposes toestablish in this rulemaking where NOX

controls are effective for a given area todemonstrate attainment. The OTAG’smodeling (in particular, OTAG strategyRun 5 described in section II.B.2, OTAGStrategy Modeling) shows that such astrategy in which a State adopted NOX

emission decreases similar to those EPAproposes to establish in this rulemakingwould achieve attainment in most ofthese areas that would becomenonattainment under the 8-hourstandard.

b. Areas attaining the 1-hour standardbut not attaining the 8-hour standard forwhich a regional transport strategy isnot sufficient for attainment of the 8-hour standard. To encourage earlyplanning and attainment for the 8-hourstandard, EPA will make the transitionalclassification available to areas notattaining the 8-hour standard that willneed additional local measures beyondthe regional transport strategy, as wellas to areas that are not affected by theregional transport strategy, providedthey meet certain criteria. To receive thetransitional classification, these areasmust submit an attainment SIP prior tothe designation and classificationprocess in 2000. The SIP mustdemonstrate attainment of the 8-hourstandard and provide for theimplementation of the necessaryemissions reductions on the same timeschedule as the regional transportreductions. The EPA will work withaffected areas to develop a streamlinedattainment demonstration. Bysubmitting these attainment plansearlier than would have otherwise beenrequired, these areas would be eligiblefor the transitional classification and itsbenefits and would achieve cleaner airmuch sooner than otherwise required.

c. Areas not attaining the 1-hourstandard and not attaining the 8-hourstandard. The majority of areas notattaining the 1-hour standard have madesubstantial progress in evaluating theirair quality problems and developingplans to reduce emissions of ozone-causing pollutants. These areas will beeligible for the transitional classificationprovided that they attain the 1-hourstandard by the year 2000 and complywith the appropriate provisions ofsection (a) or (b) above depending uponwhich conditions they meet.

2. Areas Not Eligible for the TransitionalClassification

Areas that do not attain the 1-hourstandard by 2000 are not eligible for thetransitional classification. For theseareas, their work on planning andcontrol programs to meet the 1-hourstandard by their current attainmentdate (e.g., 2005 for Philadelphia and2007 for Chicago) will take them a longway toward meeting the 8-hourstandard. In addition, the regional NOX

reductions proposed in this rulemakingwill also help these areas meet both the1-hour and 8-hour standards.

While the additional local reductionsthat these areas will need to achieve the8-hour standard must occur prior totheir 8-hour attainment date (e.g., 2010),for virtually all areas the additionalreductions needed to achieve the 8-hourstandard can occur after the 1-hour

attainment date. This approach allowsthem to make continued progresstoward attaining the 8-hour standardthroughout the entire period withoutrequiring new additional local controlsfor attaining the 8-hour standard untilthe 1-hour standard is attained. Theseareas, however, will need to submit animplementation plan within 3 years ofdesignation as nonattainment forachieving that standard. Such a plan canrely in large part on measures needed toattain the 1-hour standard. For virtuallyall of these areas, no additional localcontrol measures beyond those neededto meet the requirements of Subpart 2 ofpart D and needed in response to theregional transport strategy would berequired to be implemented prior totheir applicable attainment date for the1-hour standard. Nonattainment areasthat do not attain the 1-hour standard bytheir attainment date would continue tomake progress in accordance with therequirements of Subpart 2; the controlmeasures needed to meet the progressrequirements under Subpart 2 wouldgenerally be sufficient for meeting thecontrol measure and progressrequirements of Subpart 1 as well.

V. SIP Revisions and ApprovabilityCriteria

A. SIP Revision Requirements andSchedule

For the 1-hour NAAQS, under section110(k)(5) of the CAA, EPA has theauthority to establish the date by whicha State must respond to a SIP call. Thisdate can be no later than 18 monthsafter the SIP call is issued in the finalrulemaking. The EPA is proposing thatthe date for SIP submittal be 12 monthsafter publication of the notice of finalrulemaking. This date is appropriate inlight of the fact that States that aresubject to today’s rulemaking havealready been involved in the OTAGprocess. In addition, submitting thetransport SIP by this time will facilitatearea-specific SIP planning requiredunder Subpart 2 of CAA. Nonattainmentareas required to develop attainmentplans need to know what upwindreductions to expect and when thereductions will occur. The EPA believesthat it is appropriate for all areas subjectto this rulemaking—attainment as wellas nonattainment—to meet the sameschedule for making SIP submittals.Upwind attainment area controls are acritical element for reducing elevatedlevels of ozone and NOX emissionsflowing into the downwindnonattainment areas.

For the 8-hour NAAQS, under section110(a)(1) of the Act, EPA believes it hasthe authority to establish different


schedules for different parts of thesection 110(a)(2) SIP revision.Specifically, EPA proposes to requirefirst the portion of the 110(a)(2) SIPrevision that contains the controlsrequired under section 110(a)(2)(D). TheEPA proposes to require that the110(a)(2)(D) portions of the SIPsmandated under the 8-hour ozoneNAAQS be submitted within 12 monthsof the date of final promulgation of thisrulemaking. This will assist areas thatare ultimately designated nonattainmentfor the 8-hour standard in their SIPplanning under section 172(c) of theCAA and help avoid the kind of delaysdue to transport that were experiencedby nonattainment areas for the 1-hourstandard.

Therefore, under section 110(k)(5) forthe 1-hour NAAQS and section 110(a)(1)for the 8-hour NAAQS, a demonstrationthat each State will meet the assignedstatewide emission budget (includingadopted rules needed to meet theemission budget) must be submitted toEPA as a SIP revision within 12 monthsof the date of final promulgation of thisrulemaking. The EPA solicits commenton the time frames described above andelsewhere in this rulemaking. Asdiscussed in section V.B. of thisrulemaking, EPA will evaluate the SIPbased on particular control strategiesselected and whether the strategies as awhole provide adequate assurance thatthe budget will be achieved. The SIPrevision should include the followinggeneral elements related to the regionalstrategy: (1) baseline 2007 statewideNOX emission inventory (whichincludes growth and existing controlrequirements)— this would generally bethe emission inventory that was used tocalculate the required statewide budget,(2) a list and description of controlmeasures to meet statewide budget, (3)fully-adopted State rules for the regionaltransport strategy with compliance datesproviding for control betweenSeptember 2002 and September 2004,depending on the date EPA adopts in itsfinal rulemaking, (4) clearlydocumented growth factors and controlassumptions, and (5) a 2007 projectedinventory that demonstrates that theState measures along with nationalmeasures will achieve the State budgetin 2007. The control measures mustmeet the requirements for publichearing, be adopted by the appropriateboard or authority, and establish byregulation or permit a schedule and datefor each affected source or sourcecategory to achieve compliance. Statesshould follow existing EPA guidance onemission inventory development andgrowth projections.

The EPA recognizes that States mayneed additional detailed guidance onhow to develop effective transport-mitigation SIPs. Therefore, the EPAintends to establish a work group withStates and affected Federal agencies todetermine what types of additionalinformation and guidance will behelpful. As discussed below, this workgroup will also address what types oftracking and reporting procedures areneeded to assure States are makingsatisfactory progress towards meetingtheir required NOX budget once the SIPshave been put in place.

B. SIP Approval Criteria

1. Budget DemonstrationIn response to the final rulemaking,

each State will be required to submit aSIP revision that clearly demonstrateshow the State will achieve its statewideNOX budget by 2007. The NOX budgetdemonstration should show howemissions from each sector, orcomponent, of the NOX emissionsinventory will be addressed and that theapplication of the regional strategyalong with existing requirements willallow total NOX emissions in the Stateto be at or below the level of therequired NOX budget by 2007.

In section III, Statewide EmissionsBudgets, of this rulemaking, EPAdescribed the control strategies that EPAused in the development of thestatewide NOX emissions budgets. TheEPA believes these measures providethe most reasonable, cost-effectivemeans for mitigating significantinterstate transport. In addition, thecontrol measures are generallyconsistent with the OTAG controlstrategy recommendations. However,States have the flexibility to adopt adifferent set of control strategies so longas they achieve the 2007 budget. Thereare a variety of different controlprograms that could provide thenecessary NOX reductions. States maywish to consider the strategies that EPAused for budget development as astarting point in developing theirspecific statewide NOX strategy. WhereStates select different control measuresfor the various components of theiremissions inventory, they should clearlydefine the particular control measuresand document the methods used toestimate emissions reductions fromimplementation of the measures. Forexample, if a State elected to adopt morestringent controls for mobile sourcesthan were used in EPA’s calculation ofthe statewide budget and less stringentcontrols on utilities, the State wouldidentify the additional regulations thatwould be applied to the mobile sources

and the different limits that would beapplied to utilities. The State wouldsubmit fully adopted rules for thosesectors with documentation of theprojected emissions reductions theparticular control measures wouldachieve, along with the rules for theother sectors, and a demonstration thatthe overall control strategy whenapplied to the baseline 2007 emissionsinventory would achieve the statewide2007 emission budget. The entire NOX

emissions inventory must be accountedfor in the demonstration.

As discussed in section III.D,Recalculation of Budgets, if a State hasmore precise growth estimates andcontrol assumptions that it wishes touse in developing its NOX budgetdemonstration, and EPA agrees they areappropriate, EPA will recalculate thestatewide budget based on those revisednumbers. Because any justifiable lowergrowth estimates from the State wouldbe used in EPA’s budget calculation,lower growth could not be considered aspart of a State’s NOX control strategy toattain the budget (unless the change ingrowth is the result of clearly identifiedcontrol strategies which can be shownto provide real, permanent, andquantifiable changes in growth).

2. Control StrategiesAll the control strategies a State

selects to meet its NOX budget mustprovide real, permanent, quantifiable,and enforceable reductions. Theseattributes are consistent with thoserequired of all SIP revisions (40 CFRpart 51). Control strategies are generallycomposed of enforceable limits ormeasures applied to a source or groupof sources (i.e., sector) for the purposeof reducing emissions. Control strategiesmay be expressed as either a tonnagelimit, an emission rate, or a specifictechnology or measure. Considerationsin addition to compliance with its NOX

budget, such as local impacts, may leadto selection of a particular strategy overothers. In terms of staying within anemissions budget, the effectiveness ofthe different strategies varysignificantly. A control strategy thatemploys a fixed tonnage limitation (orcap) for a source or group of sourcesprovides the greatest certainty that aspecific level of emissions will beattained and maintained. With respectto transport of pollution, an emissionscap also provides the greatest assuranceto downwind States that air emissionsfrom upwind States will be effectivelymanaged over time. Control strategiesdesigned and enforced as an emissionsrate limitation can achieve a measurableemissions reduction, but the targetedlevel of emissions may or may not be


reached, depending on the actualactivity level of the affected source(s).Finally, control strategies designed as aspecific technology or measure have thegreatest uncertainty for achieving atargeted emissions level due touncertainty in both the activity level ofthe affected source(s) and uncertainty inthe effectiveness of the technology ormeasure.

Based on the desire to establishcontrol strategies with the greatestenvironmental certainty of providing forachievement and maintenance statewideNOX emissions budget, EPA wouldrecommend that to the maximum extentpracticable, all control strategies bebased on a fixed level of emissions fora source or group of sources. However,EPA recognizes that this option may bedifficult for some sources because: (1)the available emissions control optionsmay be limited, and (2) the techniquesfor quantifying mass emissions toensure compliance with a tonnagebudget may not be adequate. Therefore,States may select the most appropriatetype of control strategy to achieve andmaintain the desired emissionslimitation for each source or group ofsources regulated in response to thisrulemaking. To compensate for the lackof certainty inherent in some types ofcontrol strategies (i.e., control strategiesthat do not set fixed tonnage budgets)and to address rule effectivenessconcerns, States may want to considerincorporating a compliance margin intheir overall budget calculation. Acompliance margin could be used byincreasing the level of controls in theoverall budget beyond what is requiredby this rulemaking. Section VIIdiscusses an interstate cap-and-tradeprogram for large combustion sourcesthat EPA intends to develop, inconjunction with interested States.Because this is a proven and cost-effective control strategy that providesmaximum flexibility to sources, Statesmay wish to consider this option as partof their regional NOX strategy.

The EPA is also considering ways toextend the cap-and-trade program toother types of sources. The Agency’sinterest in developing such approachesis consistent with the goal in theImplementation Plan for the Revised AirQuality Standards of working ‘‘with theStates to develop control programswhich employ regulatory flexibility tominimize economic impacts onbusinesses large and small to thegreatest possible degree consistent withpublic health protection.’’ The EPArecognizes that there are importantadvantages of developing a broad-basedtrading program to provide incentivesfor the development of innovative, low-

cost ways of controlling emissions fromthese sources. Under market-basedapproaches like a cap-and-tradeprogram, there will be an incentive forsources to identify and adopt pollution-minimizing fuels, energy efficiencymeasures, or changes in product mixthat offer the lower cost reduction inemissions.

The EPA and OTAG have focused ona cap-and-trade program for largecombustion sources because it assures aproven method for achieving andmaintaining a fixed level of emissions.The EPA solicits comments onapproaches that would allow a broaderparticipation in emissions trading. Inaddressing expansion of emissionstrading beyond large combustionsources, commenters should addresswhat steps can be taken to quantifyemissions from each source involved inthe program to assure that the emissionscap is met and the costs to Federal, Stateand local governments of administeringsuch a program.

a. Enforceable Measures Approach.Enforceable measures include controlstrategies expressed as either emissionrate limitations or technologyrequirements. These control strategiesdo not provide the same environmentalcertainty that a specific emissions levelwill be met and maintained ascompared to fixed tonnage budgets.However, these control requirements arean appropriate method for achievingemissions reductions for many sourcesectors that have limited options forcontrolling and directly measuringemissions.

For control strategies that useemission rate limitations or technologyrequirements the SIP must include thefollowing elements: (1) the enforceableemission rate, technology requirement,or specific measure for each source that,when applied to year 2007 activitylevels and in aggregate with othercontrols, would meet the statewideemissions budget; (2) the projectedactivity level for each source or group ofsources, as appropriate; (3) other factorsnecessary to calculate the effect of thecontrol requirements (e.g., speeds andtemperature for mobile sourcesnecessary to calculate emissions); (4)emissions rate and activity levelmeasurement and emissions estimationprotocols for all sources, or group ofsources; (5) reporting protocols foremission rate, activity level, andemissions for all sources, or group ofsources (EPA intends to address theserequirements in a supplemental EPArulemaking); (6) enforcementmechanisms, including complianceschedules for installation and operationof all control requirements and

institution of all compliance processesby the date between September 2002and September 2004 that EPAestablishes in its final action on thisproposal; and (7) requirements foradequate penalties on the sources forexceeding applicable emissions rates orfailing to properly install or operatecontrol technologies or carry-outcompliance measures.

A State or groups of States maychoose to develop, adopt andimplement trading programs for sourcesaffected by enforceable measures. Suchtrading programs should be consistentwith EPA guidance on trading,including the Economic IncentiveProgram rules and guidance as well asguidance provided on Open MarketTrading. Such approaches could beadopted by States to help achieveemission reductions cost effectively.The EPA does not anticipate managingthe emissions data and market functionsof these trading programs that do notincorporate emissions caps.

b. Fixed Tonnage Budgets. Under thisapproach, a group of sources wouldhave their control strategy expressed asa fixed tonnage budget. Because thefixed tonnage budget approach isdesigned to maintain a specific, fixedlevel of emissions, this approach doesnot require an enforceable complianceplan that prescribes exactly howemissions reductions would beachieved. If a State elects to use a fixedtonnage budget as a control strategy, theState would have two options forimplementing the program. The Statemay choose to join the cap-and-tradeprogram that EPA proposes to developand assist in implementing for sourcesin cooperation with interested States(this program is discussed in sectionVII, Model Cap-and-Trade Program, ofthis rulemaking), or the State maychoose to develop a fixed tonnagebudget regulation separate from EPA’sprogram. The EPA cap-and-tradeprogram will incorporate all necessarySIP criteria into the program design. Ifthe State elects to develop a fixedtonnage budget program separate fromEPA’s program, the State program mustinclude the following elements: (1) thetotal seasonal tonnage emissionslimitation for the category of sourceswhich shall be enforceable at the sourcelevel by the date between September2002 and September 2004 that EPAestablishes in its final rulemakingthrough emission tonnage limitations oremission rate limitations thatautomatically adjust for growth inactivity levels over time; (2)requirements to measure andelectronically report all emissions fromeach source; and (3) requirements for


adequate penalties for exceeding anemissions limitation or emission rate.

To implement a fixed tonnage budgetprogram, a State or group of States maychoose to develop, adopt andimplement their own cap-and-tradeprogram. Such trading programs shouldbe consistent with EPA guidance ontrading, including the EconomicIncentive Program rules and guidance.The EPA does not anticipate managingthe emissions data and market functionsof these programs.

3. Control Strategy ImplementationAs discussed in section I.D.2.e,

Control Implementation and BudgetAttainment Dates, of this rulemaking,EPA is proposing that States mustimplement all of their State-adoptedNOX control strategies by a datebetween 3 to 5 years from the SIPsubmittal due date. This time framewould result in an implementationdeadline within the range fromSeptember 2002 and September 2004.The EPA is seeking comment on whichdate within this range is appropriate, inlight of the feasibility of implementingcontrols and the need to provide airquality benefits as expeditiously aspossible. Therefore, for the SIP to beapprovable, State NOX rules must allhave compliance dates providing forcontrol by the implementation deadline,which will be specified in the finalrulemaking. The EPA believes this isnecessary to assist ozone areas inmeeting their attainment obligationsunder the 1-hour standard and to assuretimely attainment of the 8-hourstandard. The EPA recognizes that thecontrol measures will not be in place intime to assist serious ozone areas inmeeting their 1999 attainment dateunder the 1-hour standard. This isunavoidable because of the time neededto complete this rulemaking and forStates to adopt and implement theirNOX measures. The next attainmentdate under the 1-hour standard is 2005for severe-15 areas. For the 8-hourstandard, the CAA provides forattainment dates of up to 5 or 10 yearsafter designations with 2 potential 1-year extensions. In light of the projecteddesignation date of 2000, the firstattainment date under the 8-hourstandard could also be 2005. For theseareas, it is important that the regionalNOX control measures be in place by nolater than September 2004—in time toprovide emissions reductions for the2005 ozone season. Implementingcontrols earlier than September 2004, orat least phasing in some controls, wouldimprove the chance for minimizingexceedances in the 3-year period up toand including the 2005 attainment year.

States required to meet a statewide NOX

budget by 2007 will continue to achieveadditional emissions reductions afterSeptember 2004 from continued phasein of Federal measures. The EPA willprovide guidance to the States on theappropriate amount of emissionreduction credit that a State may assumefrom Federal measures.

4. Growth EstimatesThe EPA believes it is important that

consistent emissions growth estimatesbe used for the State’s budgetdemonstration and for EPA’s calculationof the required Statewide emissionsbudget. If a State wishes to substitute itsown growth or control information in itsbudget analyses and can provideadequate justification for its alternativenumbers, EPA will evaluate the State’ssubmission and may recalculate therequired statewide budget to reflect theState numbers. As mentioned in theprevious section, because the revisedgrowth estimates will be included inEPA’s budget calculation, lower growthrates could not be considered part of aState’s NOX control strategy to attainthat budget unless the change in growthis the result of clearly identified controlstrategies that can be shown to providereal, permanent, and quantifiablechanges in growth. During the commentperiod for this proposal, States will havean opportunity to comment on EPA’sgrowth assumptions and justificationsfor emissions rates and controlmeasures. As described in section III.D,Recalculation of Budgets, EPAencourages requests for alterations tothe growth estimates or controlassumptions be made during thecomment period for this proposal sothat the budgets given in the finalrulemaking will incorporate thechanges. Addressing these issues priorto the final rulemaking will allow Statesto concentrate their efforts on controlstrategy development and rule adoptionprocedures during the proposed 12-month time frame for submitting theirSIP revisions.

5. Promoting End-Use Energy EfficiencyIn order to minimize compliance

costs, EPA is interested in allowingStates the maximum flexibility practicalin meeting their NOX budgets. The EPAbelieves that achievement of energyefficiency improvements in homes,buildings, and industry can be one cost-effective component of a comprehensiveState strategy. These energy efficiencyimprovements would substantiallyreduce control measures required tomeet NOX objectives. To this end, EPAwill be investigating, in consultationwith the Department of Energy’s Office

of Energy Efficiency and RenewableEnergy, how energy efficiencyopportunities can be integrated withinSIPs, while maintaining the requisitelevel of confidence that State budgetswill be met. The EPA intends to provideguidance in this area. The EPA isrequesting comment on how SIPs andassociated processes can allow for theincorporation of cost-effective, end-useenergy efficiency.

C. Review of ComplianceThe EPA believes it is essential that

progress in implementing the regionalcontrol strategy be periodically assessedafter the initial SIP submittal. This willallow early detection of implementationproblems, such as overestimates ofcontrol measure effectiveness andunderestimates of growth. The EPA willbe carefully tracking State progress andintends to propose periodic Statereporting requirements in its SNPR.Because nonattainment areas will berelying on emissions reductions in otherStates to assist them in reachingattainment, EPA believes that each Statemust have an effective program fortracking progress of the regionalstrategy. The EPA intends to establish awork group of affected States and otherimpacted Federal Agencies to determinewhat procedures to put in place toprovide adequate assurance that thenecessary emissions reductions arebeing achieved. The EPA believes thattracking efforts should be structured toavoid unnecessary burdens on States.Therefore, EPA intends to integrateactivities to track progress onimplementing the regional NOX budgetwith existing program requirementssuch as periodic emissions inventoriesand reporting under title IV for NOX.The EPA is soliciting comment on whattypes of compliance assuranceprocedures may be necessary.

The EPA recognizes that success ofthe program depends, in part, on theavailability of reliable, comprehensiveinventories of emissions. Currently, EPAis developing a separate rulemaking thatwould require statewide periodicemissions inventories. This rule wouldbe an extension of the existing periodicemission inventory requirement fornonattainment areas. In regard to theregional transport strategy, EPA intendsto use these inventories as a tool toassess progress in implementing theregional strategy, to determine whetherthe States achieved their requiredbudget by 2007, and for future transportstudies.

If tracking and periodic reportsindicate that a State is not implementingall of its NOX control measures or is off-track to meet its budget by 2007, EPA


will work with the State to determinethe reasons for noncompliance and whatcourse of remedial action is needed. TheEPA will expect the State to submit aplan showing what steps it will take tocorrect the problems. Continuednoncompliance with the NOX transportSIP may lead EPA to make a finding offailure to implement the SIP, andpotentially implement sanctions, if theState does not take corrective actionwithin a specified time period. Iftracking indicates that, due to actualgrowth and control effectiveness, theSIP is not adequate to achieve thebudget, EPA will issue a SIP call undersection 110(k)(5) for States to amendtheir NOX control strategy. As discussedabove, EPA is proposing that all State-adopted NOX strategies must beimplemented by a date within the rangeof September 2002 and September 2004.Shortly after the establishedimplementation due date, EPA willbegin checking to determine whetherStates are meeting all of their SIPobligations.

In 2007, EPA will assess how eachState’s SIP actually performed inmeeting the Statewide NOX emissionbudget. If 2007 emissions exceed therequired budget, the control strategies inthe SIP will need to be strengthened.The EPA will evaluate thecircumstances for the budget failure andissue a call for States to revise theirSIPs, as appropriate.

D. 2007 Reassessment of TransportToday’s proposal addresses the

emissions reductions necessary tomitigate significant ozone transportbased on analyses using the mostcomplete, scientifically-credible toolsand data available for the assessment ofinterstate transport. As the state ofozone science evolves over the next 10years, EPA expects there will be anumber of updates and refinements inair quality methodologies and emissionsestimation techniques. Therefore, in2007, the end year for the currentanalyses, EPA intends to conduct a newstudy to reassess ozone transport usingthe latest emissions and air qualitymonitoring data and the next generationof air quality modeling tools.

The study will evaluate theeffectiveness of the regional NOX

measures States have implemented inresponse to the final rulemaking actionin assisting downwind areas to achieveattainment. Modeling analyses will beused to evaluate whether additionallocal or regional controls are needed toaddress residual nonattainment in thepost-2007 time frame. The study willexamine differences in actual growthversus projected growth in the years up

to 2007 as well as expected futuregrowth throughout the entire OTAGregion.

The study will also review advancesin control technologies to determinewhat reasonable and cost-effectivemeasures are available for purposes ofcontrolling local and regional ozoneproblems.

The EPA expects to seek input froma wide range of stakeholders such asState and local governments, industry,environmental groups, and Federalagencies for the study. The OTAGpartnership established by the ECOSand EPA resulted in more technicalinformation and more air qualitymodeling being conducted on regionalozone transport than ever before.Because of the success of the OTAGprocess, EPA envisions working closelywith ECOS for the transportreassessment study.

E. Sanctions

1. Failure to Submit

If a State fails to submit the requiredSIP provisions, the CAA provides forEPA to issue a finding of State failureunder section 179(a). (EPA is using thephrase ‘‘failure to submit’’ to cover boththe situation where a State makes nosubmission and the situation where theState makes a submission that EPA findsis incomplete in accordance withsection 110(k)(1)(B) and 40 CFR part 51,Appendix V.) Such a finding starts an18-month sanctions clock; if the Statefails to make the required submittalwhich EPA determines is completewithin that period, one of two sanctionswill apply. If 6 months after thesanction is imposed, the State still hasnot made a complete submittal, thesecond sanction will apply. The twosanctions are: withholding of certainFederal highway funds and arequirement that new or modifiedsources subject to a section 173 newsource review program obtainreductions in existing emissions in a 2:1ratio to offset their new emissions(section 179(b)).

The EPA promulgated regulations toimplement section 179 that specify theorder in which these sanctions willapply in the case of Statenoncompliance with requirementsunder part D of title I of the CAA (40CFR 52.31). These regulations do not,however, address the imposition ofsanctions in the case of State failure tocomply with a SIP call under section110(k)(5) or to make a SIP submissionunder section 110(a)(1). Since in today’srulemaking EPA is proposing a SIP calland a requirement for a section 110(a)(1)submission, EPA believes it is

appropriate to propose the order ofsanctions if States fail to comply withthese requirements. The EPA believesthat the general scheme promulgated forsanctions should also apply here. Underthis scheme, EPA will generally applythe 2:1 offset sanction first and thehighway funding sanction second. TheEPA believes the rationale for thisapproach provided in the preamble tothe sanctions rule applies equally here(59 FR 39832, August 4, 1994).

Section 179 sets certain limits onwhere mandatory sanctions apply. Thehighway funding sanction applies indesignated nonattainment areas and the2:1 offset sanction applies in areas withpart D NSR programs. However, EPAhas additional authority to imposesanctions under section 110(m). TheEPA’s authority to impose sanctionsunder section 110(m) is triggered by anyfinding that a State failed to make arequired SIP submission. However,there is no mandatory clock for theimposition of these sanctions. The EPAmay determine whether or not to usethis authority in response to a SIPfailure, and thus they are termeddiscretionary sanctions. With thediscretionary sanctions, use of the 2:1offset sanction is still limited to areaswith part D NSR programs. However,the highway funding sanction can beapplied in any area. While sanctionsunder section 179 apply only to thedeficient area, under section 110(m) thehighway sanction can be appliedstatewide, subject to the conditions inEPA’s discretionary sanctions rule (40CFR 52.30). Because the mandatorysanctions would not be applicable in allareas that may fail to respond torequirements proposed in today’srulemaking, EPA is requesting commenton whether the discretionary sanctionsshould be used in response to a failureof a State to submit the required SIPrevision.

In addition to sanctions, a finding thatthe State failed to submit the requiredSIP revision triggers the requirementunder section 110(c) that EPApromulgate a FIP no later than 2 yearsfrom the date of the finding if thedeficiency has not been corrected. TheFIPs are discussed in the section below.

A State that submits a SIP that issubsequently disapproved, due tofailure to meet one or more of therequired elements, will be subject to thesame sanctions and FIP consequences asa State that fails to make the requiredsubmittal.

2. Failure to ImplementIf a State fails to implement its SIP,

EPA may also make a finding undersection 179. The finding triggers the


mandatory sanctions as describedabove. The EPA may also choose toapply discretionary sanctions as aconsequence of failure to implement.However, a FIP is not triggered.

F. Federal Implementation Plans (FIPS)

1. Legal Framework

The Administrator is required topromulgate a FIP within 2 years of: (1)finding that a State has failed to makea required submittal, or (2) finding thata submittal received does not satisfy theminimum completeness criteriaestablished under section 110(k)(1)(A)(56 FR 42216, August 26, 1991), or (3)disapproving a SIP submittal in wholeor in part. Section 110(c)(1) mandatesEPA promulgation of a FIP if theAdministrator has not yet approved acorrection proposed by the State beforethe time a final FIP is required to bepromulgated.

2. Timing of FIP Action

The EPA views seriously itsresponsibility to address the issue ofregional transport of ozone and ozoneprecursor emissions. Decreases in NOX

emissions are needed in the Statesnamed in the rulemaking to enable thedownwind States to first develop plansto achieve the clean air goals and thento carry out those plans and actuallyachieve clean air for their citizens.Thus, although the CAA allows EPA upto 2 years after the finding topromulgate a FIP, EPA intends toexpedite the FIP promulgation to helpassure that the downwind States realizethe air quality benefits of regional NOX

reductions as soon as practicable. Thisis consistent with Congress’s intent thatattainment occur in these downwindnonattainment areas ‘‘as expeditiouslyas practicable’’ (sections 181(a), 172(a)).Therefore, EPA intends to propose FIPsat the same time as final action is takenon this proposed Ozone Transport SIPRulemaking. Furthermore, EPA intendsto make a finding and promulgate a FIPimmediately after the SIP submittal duedate for each upwind State that fails tosubmit a SIP that meets the terms of thefinal rulemaking of this proposal.

As described elsewhere in thisrulemaking, EPA is proposing to requirespecific States to decrease theiremissions of NOX in order to reduce thetransport of ozone and ozone precursorswhich affects nonattainment areas overhundreds of miles downwind. Thisproposal allows States 12 months todevelop, adopt and submit revisions totheir SIPs in response to the finalrulemaking. The EPA intends toexpeditiously approve SIP revisions thatmeet the rulemaking requirements. For

States that fail to make the requiredsubmittal or fail to submit a completeSIP revision response, EPA wouldpromulgate a FIP as described in theabove section. Where the SIP iscomplete but EPA disapproves it, EPAwould also promulgate a FIP. The EPAmay choose to propose a FIP at the sametime as proposing disapproval of aState’s response to the final rulemaking.Thus, EPA intends to move quickly topromulgate a FIP where necessary. TheEPA solicits comment on the timeframes described above and elsewherein this rulemaking .

3. Statewide Emissions BudgetsIn the FIP proposal, each State would

be allocated by EPA the same statewideemissions budget as describedelsewhere in this document. Thatstatewide budget is given to States thatare found to significantly contribute tononattainment in downwind States asdescribed in section II. The statewidebudget is derived from the set ofreasonable, cost-effective measuresapplied to the various source sectors asdiscussed in section III.

4. FIP Control MeasuresIn contrast to the SIP process—where

selection and implementation of controlmeasures is the primary responsibilityof the State—in the case of a FIP, it isEPA’s responsibility to select the controlmeasures for each source sector andassure compliance with those measures.Thus, while the FIP would be designedby EPA to achieve the same totalstatewide emissions decrease as thatdescribed in final action on today’sproposal, the specific control measuresassigned in the FIP could be differentfrom what a State might choose.

In selecting the specific controlmeasures for a FIP, EPA would take intoaccount the administrative feasibility aswell as cost effectiveness of variouscontrol options. In developing thebudget calculations, EPA generallyagreed with the direction of the OTAGrecommendations that EPA developFederal measures for certain sourcescategories—mobile sources inparticular—and that the States developstationary source measures in responseto this rulemaking. It is unlikely thatEPA’s FIP would focus on mobile sourceprograms such as I/M or transportationcontrol measures because thesemeasures are not as cost effective asothers for controlling regional NOX

emissions and because it would bedifficult for a limited Federal staff toimplement such programs, especiallywithout detailed knowledge of localconcerns and circumstances. Forstationary sources, the EPA budget

calculations include large- and medium-sized stationary sources. As in the casewith mobile sources, a program toreduce emissions from stationarysources that is reasonable for States toimplement, may be less feasible for EPAto implement due to factors such as alarge number of affected sources.

Therefore, for the stationary sourcesector, EPA’s FIP would likely proposeto focus controls more on the largerstationary sources. This approach wouldtake account of the potential need forFederal staff to implement the programin more than one State by reducing thenumber of sources affected so that theprogram is more manageable. It followsthat greater emissions decreases mightbe needed from the remaining set ofstationary sources than is suggested bythe EPA’s statewide budget calculation(described in section III). That is, tomake up the short-fall in the statewidebudget from medium-sized stationarysources, additional decreases might beneeded from the large stationary sourcesin a FIP program.

5. FIP Trading ProgramIn order to minimize the burden on

sources, EPA would establish in the FIPan interstate emissions trading program.The FIP trading program would bedesigned to be compatible with theemissions trading program describedelsewhere in this rulemaking.Development of such emissions tradingprograms would use the processidentified in the OTAG July 10, 1997recommendation on trading—a jointEPA/State effort with appropriatestakeholder input.

6. Section 105 GrantsThe EPA provides annual funding to

States under section 105 of the CAA tocarry out Act-related programs. WhereEPA must develop, adopt andimplement a FIP, the Agency willconsider withholding all or a portion ofthe grant funds normally appropriatedto the State. Those funds would be usedby EPA in the FIP work.

G. Other ConsequencesIf a State is implementing all of its

control measures but is off course tomeet its 2007 budget due to errors ingrowth estimates or controlassumptions, EPA will consider issuinga subsequent SIP call for the State torevise its implementation strategy.

VI. States Not Covered by ThisRulemaking

Based upon all the available technicalinformation, the EPA is proposing tofind that the following 15 States in theOTAG region do not make a significant




contribution to downwindnonattainment: Arkansas, Florida, Iowa,Kansas, Louisiana, Maine, Minnesota,Mississippi, North Dakota, Nebraska,New Hampshire, Oklahoma, SouthDakota, Texas, Vermont. These 15 Statesare not required to meet an assignedStatewide NOX emission budget. Basedupon comments received during thecomment period, as well as anyadditional modeling and technicalanalyses, these States could be found tobe significant contributors tononattainment. If this is the case, EPAwill publish a SNPR.

These States may need to cooperateand coordinate SIP developmentactivities with other States. Forexample, the OTAG recommendation onutility NOX controls (see Appendix B)recognized that the State of Iowa wouldwork with Wisconsin in developing theSoutheast Wisconsin ozone SIP; that theState of Kansas would work withMissouri in the continued progress ofthe Kansas City ozone SIP; and thatOklahoma, Texas, Arkansas, andLouisiana would share the results oftheir urban and regional scale modelingwith Missouri. The EPA also believesthat the 11 States (i.e., Connecticut,Delaware, Maine, Maryland,Massachusetts, New Hampshire, NewJersey, New York, Pennsylvania, RhodeIsland and Vermont) plus the District ofColumbia’s consolidated metropolitanstatistical area (including northernVirginia) that are included in the OTRshould continue coordinating theiractivities through the OTC to providefor attainment of the ozone NAAQS inthat region.

States with interstate nonattainmentareas for the 1-hour standard and/or thenew 8-hour standard are expected towork together to reduce emissions tomitigate local scale interstate transportproblems in order to provide forattainment in the nonattainment area asa whole. For example, New Hampshireshould work with Massachusetts for theBoston-Lawrence-Worcesternonattainment area. For the 8-hourstandard, parts of local scale interstatenonattainment areas may be located inLouisiana and Texas as well as inArkansas and Tennessee. These Statesshould also coordinate their planningefforts.

In addition, areas in these States maybe able to receive the transitionalclassification as described in section IV,Implementation of Revised Air QualityStandards. The OTAG’s modeling (inparticular, OTAG strategy Run 5described in section II.B.2, OTAGStrategy Modeling) shows that a strategyin which a State-adopted NOX emissiondecreases similar to those EPA proposes

to establish in this rulemaking wouldachieve attainment in most of theseareas that would become nonattainmentunder the 8-hour standard. If a Statewishes to consider this as a viableoption for meeting its early SIPrequirement and receiving thetransitional area classification, EPA willwork with the State to achieve this.Section III, Statewide Emission Budgets,describes EPA’s process for establishingthe statewide NOX emission budgets.(Note that States not covered by thisrulemaking may be eligible for thetransitional classification by meansother than adopting NOX emissionreductions similar to those in thisproposal. In addition to attaining the 1-hour standard, by at least 2000, areas inStates not covered by this rulemakingthat do not wish to adopt NOX emissionreductions similar to those in thisproposal must submit an attainment SIPprior to the designation andclassification process in 2000. The SIPmust demonstrate attainment of the 8-hour standard and provide for theimplementation of the necessaryemissions reductions on the same timeschedule as the regional transportreductions.)

The EPA strongly suggests that Stateswith new nonattainment counties forthe 8-hour standard should consider theoption of this strategy since our analysisindicates that nearly all newnonattainment counties are projected tocome into attainment as a result of thisstrategy. States will benefit by earlyaction to aid their cities in these newcounties in the attainment of the 8-hourstandard and receipt of transitionalstatus which will result in no furthercontrols on local sources. Of the 10 newcounties in the 15 States that are notcovered by this rulemaking, based onOTAG modeling, all 10 are projected tocome into attainment as result of theregional NOX reductions included in theOTAG Run 5 modeling run.17 A newcounty is defined as a county thatviolates the 8-hour standard but not the1-hour standard and is not located in anarea for the 1-hour standard designatednonattainment as of July 1997. (In thedocket to this rulemaking is a table withassociated documentation in which EPAlists these 10 new counties in the 15States with an indication of whether thecounty is projected to attain the 8-hourozone standard based on the OTAG Run5 modeling run.)

This county information should beunderstood with two caveats. First, thislist of counties is based on air qualitydata from 1993–95. The data from this

period will not be the basis fornonattainment area designations for the8-hour ozone standard. Thosedesignations will be made in the 2000time frame and will be based on themost recent air quality data available atthat time (1997–1999). Therefore, whileEPA expects that the vast majority ofnew counties will attain as a result ofthe NOX regional control strategy, thenumber of new counties may be more orless than the number indicated above.The EPA is also currently updating thislist based on more current air qualitydata which will be included in thedocket to the final rule.

Second, the estimate of whichcounties will attain the 8-hour standardis based on the specific assumptionsmade by the OTAG in Run 5. Becausethe proposed budgets are similar but notidentical to those contained in Run 5,the estimate may change when this ruleis final and implemented. In addition,some of the assumptions used tocalculate the proposed budgets maychange in response to comments EPAmay receive on various portions of thisrulemaking. Therefore, the estimate ofwhich areas will attain the standardsthrough the final regional NOX strategymay be higher or lower than the numberindicated above.

In addition, areas in the region notcovered by the proposed NOX reductionstrategy in this rulemaking that wouldexceed the new standard after thevoluntary adoption of the regionalstrategy, including areas that do notmeet the current 1-hour standard, wouldbenefit as well because the regional NOX

program would reduce the extent ofadditional local measures needed toachieve the 8-hour standard. In manycases, these regional reductions may beadequate to meet CAA progressrequirements for a number of years,allowing areas to defer additional localcontrols. In the 15 States, of the 20counties that violate the 8-hour standardwhich are located in an area designatednonattainment for the 1-hour standardas of July 1997, 14 are projected to comeinto attainment of the 8-hour standardas a result of OTAG Run 5 regional NOX

reductions. 18 The caveats noted abovefor new counties also apply to theinformation presented here. (In thedocket to this rulemaking is a table withassociated documentation in which EPAlists these 20 counties in the 15 States,including an indication of whether thearea is projected to attain the 8-hourozone standard as a result of regional


NOX reductions included in the OTAGRun 5 modeling run.)

States that opt in to meet the early SIPrequirement this way would not beeligible to participate in the tradingprogram with the States required in thisrulemaking to revise their SIPs althoughthey could develop intrastate tradingprograms. This limitation is needed toavoid the movement of emissions, viatrades, from States that do notcontribute to nonattainment to Statesthat do contribute to nonattainment.

Section V, SIP Revisions andApprovability Criteria, discusses generalSIP requirements for States that EPA hasfound significantly contribute todownwind nonattainment. The EPAintends to establish a workgroup withthe affected States to determine whattype of reporting and trackingmechanisms are needed to assure Statesare making steady progress towardmeeting their 2007 budgets. Oneimportant element of tracking will be toassess actual growth versus projectedgrowth. While EPA will not beestablishing new reporting requirementsfor States exempted from thisrulemaking, EPA intends to periodicallyreview emissions in the exempted Statesto determine the impacts of anyemissions increases on downwindnonattainment areas. In addition, asdiscussed in section V.F, 2007Reassessment of Transport, in 2007 EPAwill be conducting a reassessment oftransport in the full OTAG region toevaluate the effectiveness of the regionalNOX measures and whether additionalregional controls are needed.

If States not covered by thisrulemaking choose to adopt budgetsbased on the rationale outlined above,EPA will work with those States todetermine what an appropriatestatewide budget should be. The EPAwould encourage those States toconsider statewide budgets based onadoption of NOX emission decreasessimilar to those EPA proposes herein toestablish for States covered by thisrulemaking.

VII. Model Cap-and-Trade ProgramThe EPA is planning to develop and

administer an interstate cap-and-tradeprogram that could be used toimplement a fixed tonnage budget.States electing to reduce emissions fromthe types of sources covered by thisprogram in order to achieve andmaintain the statewide emissionsbudget could voluntarily participate inthis program. Much of the discussion todate on the development of a cap-and-trade program has focussed onestablishing a cap-and-trade program forlarge combustion sources. As noted

earlier, EPA is also considering ways toextend the cap-and-trade program toother types of sources.

The EPA is planning to develop a cap-and-trade program for large combustionsources because it provides a provenand cost-effective method for achievingand maintaining a fixed tonnage budgetwhile providing maximum complianceflexibility to affected sources. Bycapping emissions, the environmentalintegrity of this market-based approachis assured. For example, as totalelectricity generation grows, averageemissions over the ozone season wouldnot exceed the cap. In addition, thereductions achieved across sectors willbe those of lowest cost, since eachsource will identify and implement thespecific control technology, pollution-minimizing fuel, energy efficiency, orproduction mix that offers the greatestamount of pollution reduction at theleast cost. Overall, implementation of aregional cap-and-trade program wouldlikely lower the costs of attainingreductions through more efficientallocation of emission reductionresponsibilities, minimize the regulatoryburden for pollution sources, and serveto stimulate technology innovation.

A number of regulatory programs arecurrently in use or under developmentthat use a cap-and-trade program forlarge combustion sources. Theseregulatory systems include the EPA’sAcid Rain Program for SO2 emissions,the South Coast Air QualityManagement District’s Regional CleanAir Incentives Market for SO2 and NOX,and the OTC’s NOX Budget Program.Experience with these regulatoryprograms indicates that establishing atonnage budget for large combustionsources is currently feasible and costeffective. These approaches existbecause there is a range of optionsavailable for controlling and measuringemissions from these sources. Formeasuring emissions, continuousemissions monitors currently installedat most sources participating in theseapproaches provide accurate andcomplete emissions measurementswhich enable the administrators of theseapproaches to easily and accuratelytrack and enforce emissions on atonnage basis.

In developing the cap-and-tradeprogram, EPA will build upon the workproduced by OTAG’s Trading/Incentives Work Group. Based uponOTAG’s products and upon experiencefrom other relevant efforts, a model rulewill be developed that details theprogram requirements and provisions ofa cap-and-trade program, including:affected sources, monitoringrequirements, and market features. In

establishing the specific programapplicability, EPA expects to proposeinclusion of those large combustionsources that are most cost-effective forcontrolling emissions, while alsocapturing the majority of NOX emissionsfrom the stationary source sector. Themonitoring requirements are expected tobe based largely on existingrequirements in 40 CFR Part 75. Marketfeatures of the program will addresssuch issues as the basic design of thetrading system, the process for settingemission limitations (e.g., allocation ofallowances, generation performancestandard, etc.), and provisions foremissions trading and banking. The EPAwill work to develop a cap-and-tradesystem with market features that areeasily understood to facilitate maximumparticipation, minimum transactioncosts, and maximum cost savings. TheEPA will also take comment on ways toinclude a broader set of industrial andmobile sources within the cap-and-tradesystem.

The EPA plans to develop the cap-and-trade program, in coordination withStates interested in participating in sucha system. The EPA will hold twoworkshops in late 1997 to provide Statesand stakeholders an opportunity tocomment on the trading programframework prior to proposal, asrecommended by the OTAG. Theproduct of these workshops would be amodel rule that EPA would then publishfor comment in the Federal Registerprior to finalization of this proposal.States electing to participate in thisprogram would either adopt the modelrule by reference or State regulationsthat are consistent with the model rule.The preamble to the model rule wouldoutline EPA and State responsibilitiesfor implementing the program.Generally, EPA expects that it would beresponsible for managing the emissionsdata and market functions of theprogram and that States would have theprimary responsibility for enforcing therequirements of the program.

VIII. Regulatory AnalysisUnder Executive Order 12866 (58 FR

51735, October 4, 1993), the Agencymust determine whether the regulatoryaction is ‘‘significant’’ and thereforesubject to Office of Management andBudget (OMB) review and therequirements of the Executive Order.The Order defines ‘‘significantregulatory action’’ as one that is likelyto result in a rule that may: (1) have anannual effect on the economy of $100million or more or adversely affect in amaterial way the economy, a sector ofthe economy, productivity, competition,jobs, the environment, public health or


19 This category includes industrial, commercial,and institutional boilers, reciprocating engines, gasturbines, process heaters, cement kilns, furnaces atiron, steel, and glass-making operations, and nitricacid, adipic acid and other plants with industrialprocesses that produce NOX

safety, or State, local, or tribalgovernments or communities; (2) createa serious inconsistency or otherwiseinterfere with an action taken orplanned by another agency; (3)materially alter the budgetary impact ofentitlements, grants, user fees, or loanprograms or the rights and obligations ofrecipients thereof; or (4) raise novellegal or policy issues arising out of legalmandates, the President’s priorities, orthe principles set forth in the ExecutiveOrder.

Pursuant to the terms of ExecutiveOrder 12866, it has been determinedthat this proposal is a ‘‘significantregulatory action’’ because it will havean annual effect on the economy ofapproximately $2 billion. As such, thisaction was submitted to OMB forreview. Any written comments fromOMB to EPA and any written EPAresponse to those comments areincluded in the docket. The docket isavailable for public inspection at EPA’sAir Docket section, which is listed inthe ADDRESSES section of this preamble.

Based on the 2 years of analysisconducted by OTAG and othersupplemental data, the Agencydeveloped an approach that is presentedin this proposal for reducing thetransport of ozone emissions over longdistances by lowering NOX emissionsfrom major sources. Currently, themovement of ozone from one region toanother makes compliance with theexisting NAAQS difficult for certainnonattainment areas. Further, Stateefforts to reach attainment of the ozonestandard through local measures can bevery expensive. In essence, thisproposal is a regulatory action designedto improve the effectiveness andefficiency of State and EPA efforts toattain and maintain the NAAQS. TheOTAG recommended that EPA focus onrequiring appropriate States to reducesummer NOX emissions in threecategories: mobile sources, electricpower plants, and other stationarysources. The Agency adopted thisapproach in developing this proposal toestablish emissions budgets for 22 States

and the District of Columbia. Notably,the Agency is already establishingnational requirements for mobile sourcereductions that OTAG recommended.Therefore, EPA did not estimate theirimpacts in this regulatory analysis.Agency actions with respect to mobilesources have been and will be addressedin separate rulemaking activities that aredescribed below.

Mobile Sources

A number of EPA programs designedto reduce NOX and other emissions fromhighway vehicles and nonroad engineshave not yet been implemented. Someof these programs have beenpromulgated but have implementationdates which have not yet arrived. Otherprograms have been proposed but havenot been promulgated, and still otherprograms are expected to be proposed inthe near future. The following table listssome of these mobile source controlprograms and describes their status as ofthe date of this rulemaking.

TABLE VIII–1.—ANTICIPATED MOBILE SOURCE CONTROL MEASURES

Measure Current status

National Low-Emitting Vehicle Standards (NLEV) ................................................................................................ Final; not yet implemented.2004 Heavy-Duty Vehicle Standards ..................................................................................................................... Proposed.FTP Revisions ........................................................................................................................................................ Final; not yet implemented.Federal Small Engine Standards, Phase II ........................................................................................................... Proposal in 1997.Federal Marine Engine Standards (for diesels >50 hp) ........................................................................................ Proposal in 1997.Federal Locomotive Standards .............................................................................................................................. Proposed.1997 Proposed Nonroad Diesel Engine Standards .............................................................................................. Proposal in 1997.Tier 2 Light-Duty Vehicle Standards ...................................................................................................................... Under study.

All of the programs listed in thepreceding table will be implemented ona nationwide basis (except NLEV whichis applicable in 49 States). The EPAcontinues to evaluate the need foradditional Federal controls on mobilesource emissions and may proposeadditional measures as conditionswarrant. In addition, EPA continues toencourage States to evaluate as part oftheir SIPs the appropriateness of mobilesource emission control programs thatcan be implemented on a local orStatewide basis such as I/M programs,RFG, transportation control measuresand clean-fuel fleets.

As described in section III, StatewideEmission Budgets, the emission targetsfor the mobile source sectors (highwayvehicle emissions and nonroademissions) were developed byestimating the emissions expected toresult from the projected activity levelin 2007. These targets do not assume theimplementation of any additionalprograms beyond those already reflectedin SIPs or expected to be implemented

at the Federal level, including thoselisted in Table VIII–1. All of theseprograms would be implemented evenin the absence of today’s proposed rule.States and industry will not bear anyadditional mobile source control costsdue to this proposal, unless a Statechooses to implement additional mobilesource programs under its ownauthority and to correspondingly limitthe scope or reduce the stringency ofnew controls on stationary sources. TheEPA presumes a State would do so onlyif it found a net savings to its economyin doing so. Furthermore, the cost ofsuch state-operated programs willdepend on their specific design, whichEPA is unable to predict. The EPA hastherefore not included the costs ofcurrent or new Federal mobile sourcecontrols in its analysis of the costs ofthis proposal. Information on the costsof the various proposed or promulgatedFederal measures can be found in theFederal Register notices for therespective measures.

Electric Power Industry and OtherStationary Sources

The EPA is proposing to establish asummer season NOX emissions budgetfor 22 States and the District ofColumbia based on reducing emissionsfrom the electric power industry andother stationary sources.19 This willlead to the placement of NOX controlson operating units in these twocategories that the Agency has notcovered in other specific rulemakingactivities. Therefore, EPA has estimatedthe NOX emissions reductions andannual incremental costs in the year2005 resulting from this proposal.

The OTAG recognized the value ofmarket-based approaches to loweringemissions from power plants and largeindustrial sources. It also encouragedEPA to consider the value of allowing


20 The ozone season in this analysis covers May1 through September 30.

‘‘banking’’ as a program element in anytrading program that it would want torun with the States. The Agency agreesthat a market-based approach withtrading and banking is preferable andwants to work with all States covered bythis rulemaking to establish such aprogram. The EPA currently believesthat for such a program to be effectiveand administratively practicable, theprogram should have an emissions capand allow trading between sources in allthe States that are covered. TheAgency’s economic analysis is based onthis view.

Analytical limitations kept EPA fromestimating the costs of a single cap-and-trade program for the electric powerindustry and other stationary sources.The Agency can only estimate theimpacts of a cap-and-trade programacross all States covered in thisrulemaking for the electric powerindustry at the current time.

For its analysis, the Agency assumedthat power plants have a trading andbanking program that begins in 2005with a summer NOX emissions cap of489 thousand tons. This is the NOX

budget component for the electric powerindustry that is discussed earlier in thepreamble. This type of programrepresents EPA’s current views of howa reasonable trading program would beconstructed. The Agency estimates thatclose to 800 electric power generatingsources will come under this program.For other stationary sources, EPAassumed in its economic analysis thatthere would be a regulatory programthat would not allow summer NOX

emissions in 2005 to exceed 466thousand tons. This is the total NOX

budget component for other stationarysources discussed earlier in thePreamble. In this analysis, EPA set anemissions cap for each State based on itsshare of the NOX budget component thatEPA has developed and assumes thateach State places controls on its sourcesin a manner that minimizes compliancecosts in that State (a ‘‘least-cost’’regulatory approach is used). The EPAestimates that the States would placecontrols on about 9,000 other stationarysources to comply with EPA’srequirements. Given that the Agencycould not estimate the costs of a singlecap-and-trade program for the electricpower industry and other stationarysources, the total cost estimate of thisproposal is likely to be overstated to theextent that trading would occur betweenfacilities in both groups.

For the electric power industry, EPAwas able to estimate the costs andemissions changes based on twopossible baseline scenarios for thefuture. For an Initial Base Case, EPAconsidered only the implementation ofPhase I (RACT requirements) of the OTCMOU and other existing CAArequirements. For a Final Base Case,EPA considered implementation ofPhase II and Phase III of the OTC MOU,which lowered the NOX emissionslevels in the Northeastern United Statesin the baseline. For the other stationarysources, the Agency was only able toconsider the implementation of Phase Iof the OTC MOU and estimate the NOX

emission reductions and incremental

costs from the Initial Base Case. For theFinal Base Case, EPA knows that theemissions reductions and incrementalcosts are going to be less than wouldoccur in the Initial Base Case.

Table VIII–2 shows the NOX

emissions levels that EPA predicts willoccur for each source category in theInitial Base Case and Final Base Caseand after States amend their SIPs tomeet the NOX emission budgetrequirements in this proposal. Notably,some types of control technologies canbe used on a seasonal basis and othershave to be used year round. Becausethere are benefits from reducing NOX

throughout the year, the annual andseasonal changes in NOX emissions areboth reported.20 The EPA’s analysis ofthe use of cap-and-trade program for theelectric power industry showed thatthere would be significant reductions inNOX emissions occurring from electricgeneration units throughout the areacovered by the proposed rule.

Table VIII–3 shows the annualincremental costs that the Agencyestimates the regulated community willincur in 2005, the first full year ofimplementation of this rule by theStates in the two Base Cases. The costspresented here reflect trading acrossStates for electric power generationunits and cost minimization withinStates for other stationary sources. Forthe Initial Base Case, the total annualincremental costs are estimated to be$2,072 million in 2005. For the FinalBase Case, the total annual incrementalcosts are estimated to be lower than$1,992 million in 2005.

TABLE VIII–2.—NOX EMISSIONS IN 2005 FOR ALTERNATIVE BASE CASES AND AFTER COMPLIANCE WITH THE OZONETRANSPORT RULEMAKING

[1,000 NOX tons]

Source category

Initial base case (phase IOTC MOU)

Final base case (phase II/III OTC MOU)

Under proposed rule im-plementation

Ozone sea-son Annual Ozone sea-

son Annual Ozone sea-son Annual

Electric Power Industry ..................................................... 1,490 3,497 1,427 3,423 489 2,278Other Stationary Sources ................................................. 698 1,666 <698 <1,666 466 1,227

Total ........................................................................... 2,188 5,163 <2,125 <5,089 955 3,505

Note: EPA was only able to consider partial and full implementation of the Ozone Transport Commission Memorandum of Understanding forthe electric power industry. Controls on the electric power industry occur through cap-and-trade. Controls on Other stationary sources occur byStates implementing an approach applying least-cost controls.


TABLE VIII–3.— INCREMENTAL ANNUAL COSTS IN 2005 FOR COMPLIANCE WITH THE OZONE TRANSPORT RULEMAKINGUNDER ALTERNATIVE BASE CASES

[Million 1990 dollars]

Source category

Initial basecase (phase

I OTCMOU)

Final basecase (phase

II/III OTCMOU)

Electric Power Industry .................................................................................................................................................... $1,687 $1,607Other Stationary Sources ................................................................................................................................................. 385 <385

Total .......................................................................................................................................................................... 2,072 <1,992

Note: EPA was only able to consider partial and full implementation of the Ozone Transport Commission Memorandum of Understanding forthe electric power industry. Controls on the electric power industry occur through cap-and-trade. States control Other stationary sources by im-plementing a least-cost approach.

During the OTAG process, there aroseconcern over whether the States wouldenter the trading program that EPAoffered to form and that they wouldinstead end up employing command-and-control approaches to comply withEPA’s proposed rulemakingrequirements. There were discussions ofthe possible application of rate-basedcontrols on electric generation. Inkeeping with these discussions, EPA hasalso estimated the costs of this type ofcontrol for electric power generationunits. The EPA estimates that theelectric power industry in the 23jurisdictions covered by this rulemakingwill incur an annual incremental costunder the Final Base Case of $2,108million, if during the ozone season,these plants are regulated by anemission limitation of .15 pounds ofNOX per million Btus of heat input.Under the Initial Base Case, the costswould be $2,189 million. A comparisonof this cost with that in Table VIII–3reveals that a cap-and-trade program forthe electric power industry is much lesscostly than a traditional rate-basedprogram.

IX. Air Quality Analyses

As discussed in section III, StatewideEmissions Budgets, EPA has used acomparative cost-effectiveness approachto identify a set of control measures forachieving the emissions budgets forStates found to make a significantcontribution to downwindnonattainment (see section II, Weight ofEvidence Determination of SignificantContribution). These controls aregenerally consistent with OTAG’srecommendations. The OTAG didperform model simulations to assess theair quality benefits of a range of regionalstrategies. In particular, OTAG strategyRun 5 (see Appendix E) provides largeair quality benefits over broad portionsof the region. This strategy includesregional NOX controls similar to what isbeing proposed in this rulemaking. TheEPA intends to estimate the impacts of

the proposed statewide emissionbudgets using air quality modeling forinclusion in the SNPR.

X. Nonozone Benefits of NOX

Reductions

In addition to contributing toattainment of the ozone NAAQS,decreases of NOX emissions will alsolikely help improve the environment inseveral important ways. On a nationalscale, decreases in NOX emissions willalso decrease acid deposition, nitrates indrinking water, excessive nitrogenloadings to aquatic and terrestrialecosystems, and ambient concentrationsof nitrogen dioxide, particulate matterand toxics. On a global scale, decreasesin NOX emissions will, to some degree,reduce greenhouse gases andstratospheric ozone depletion. Thus,management of NOX emissions isimportant to both air quality andwatershed protection on national andglobal scales. In its July 8, 1997 finalrecommendations, OTAG stated that it‘‘recognizes that NOX controls for ozonereductions purposes have collateralpublic health and environmentalbenefits, including reductions in aciddeposition, eutrophication, nitrification,fine particle pollution, and regionalhaze.’’ These and other public healthand environmental benefits associatedwith decreases in NOX emissions aresummarized below. (17)

Acid Deposition: Sulfur dioxide andNOX are the two key air pollutants thatcause acid deposition (wet and dryparticles and gases) and result in theadverse effects on aquatic and terrestrialecosystems, materials, visibility, andpublic health. Nitric acid depositionplays a dominant role in the acid pulsesassociated with the fish kills observedduring the springtime melt of thesnowpack in sensitive watersheds andrecently has also been identified as amajor contributor to chronicacidification of certain sensitive surfacewaters.

Drinking Water Nitrate: High levels ofnitrate in drinking water is a healthhazard, especially for infants.Atmospheric nitrogen deposition insensitive watersheds can increasestream water nitrate concentrations; theadded nitrate can remain in the waterand be transported long distancesdownstream.

Eutrophication: NOX emissionscontribute directly to the widespreadaccelerated eutrophication of UnitedStates coastal waters and estuaries.Atmospheric nitrogen deposition ontosurface waters and deposition towatershed and subsequent transportinto the tidal waters has beendocumented to contribute from 12 to 44percent of the total nitrogen loadings toUnited States coastal water bodies.Nitrogen is the nutrient limiting growthof algae in most coastal waters andestuaries. Thus, addition of nitrogenresults in accelerated algae and aquaticplant growth causing adverse ecologicaleffects and economic impacts that rangefrom nuisance algal blooms to oxygendepletion and fish kills.

Global Warming: Nitrous oxide (N2O)is a greenhouse gas. Anthropogenic N2Oemissions in the United Statescontribute about 2 percent of thegreenhouse effect, relative to totalUnited States anthropogenic emissionsof greenhouse gases. In addition,emissions of NOX lead to the formationof tropospheric ozone, which is anothergreenhouse gas.

Nitrogen Dioxide (NO2): Exposure toNO2 is associated with a variety of acuteand chronic health effects. The healtheffects of most concern at ambient ornear-ambient concentrations of NO2

include mild changes in airwayresponsiveness and pulmonary functionin individuals with pre-existingrespiratory illnesses and increases inrespiratory illnesses in children.Currently, all areas of the United Statesmonitoring NO2 are below EPA’sthreshold for health effects.


Nitrogen Saturation of TerrestrialEcosystems: Nitrogen accumulates inwatersheds with high atmosphericnitrogen deposition. Because mostNorth American terrestrial ecosystemsare nitrogen limited, nitrogen depositionoften has a fertilizing effect, acceleratingplant growth. Although this effect isoften considered beneficial, nitrogendeposition is causing important adversechanges in some terrestrial ecosystems,including shifts in plant speciescomposition and decreases in speciesdiversity or undesirable nitrate leachingto surface and ground water anddecreased plant growth.

Particulate Matter (PM): NOX

compounds react with other compoundsin the atmosphere to form nitrateparticles and acid aerosols. Because oftheir small size nitrate particles have arelatively long atmospheric lifetime;these small particles can also penetratedeeply into the lungs. PM has a widerange of adverse health effects.

Stratospheric Ozone Depletion: Alayer of ozone located in the upperatmosphere (stratosphere) protectspeople, plants, and animals on thesurface of the earth (troposphere) fromexcessive ultraviolet radiation. N2O,which is very stable in the troposphere,slowly migrates to the stratosphere. Inthe stratosphere, solar radiation breaksit into nitric oxide (NO) and nitrogen(N). The NO reacts with ozone to formNO2 and molecular oxygen. Thus,decreasing N2O emissions would resultin some decrease in the depletion ofstratospheric ozone.

Toxic Products: Airborne particlesderived from NOX emissions react in theatmosphere to form various nitrogencontaining compounds, some of whichmay be mutagenic. Examples oftransformation products thought tocontribute to increased mutagenicityinclude the nitrate radical, peroxyacetylnitrates, nitroarenes, and nitrosamines.

Visibility and Regional Haze: NOX

emissions lead to the formation ofcompounds that can interfere with thetransmission of light, limiting visualrange and color discrimination. Mostvisibility and regional haze problemscan be traced to airborne particles in theatmosphere that include carboncompounds, nitrate and sulfate aerosols,and soil dust. The major cause ofvisibility impairment in the easternUnited States is sulfates, while in theWest the other particle types play agreater role.

XI. Impact on Small EntitiesThe Regulatory Flexibility Act, 5

U.S.C. 601(a), provides that wheneveran agency is required to publish ageneral notice of rulemaking, it must

prepare and make available a regulatoryflexibility analysis (RFA). An RFA isrequired only for small entities that aredirectly regulated by the rule. See Mid-Tex Electric Cooperative, Inc. v. FERC,773 F.2d 327 (D.C. Cir. 1985) (agency’scertification need only consider therule’s impact on regulated entities andnot indirect impact on small entities notregulated); Colorado State Banking Bd.v. Resolution Trust Corp., 926 F.2d 931(10th Cir. 1991). This rulemakingsimply requires States to develop,adopt, and submit SIP revisions, anddoes not directly regulate any entities.Accordingly, pursuant to 5 U.S.C.605(b), the Administrator certifies thatthis rule will not have a significanteconomic impact on a substantialnumber of small entities. Furthermore,because affected States will havediscretion to choose which sources toregulate and how much emissionsreductions each selected source mustachieve, EPA cannot now predict theeffect of this rule on small entities. Inaddition, if States adopt the controlmeasures that form the basis of theproposed State budget, there will belittle, if any, effect on small businesses.

XII. Unfunded Mandates Reform ActTitle II of the Unfunded Mandates

Reform Act of 1995 (UMRA), Pub. L.104–4, establishes requirements forFederal agencies to assess the effects oftheir regulatory actions on State, local,and tribal governments and the privatesector. Under section 202 of the UMRA,EPA generally must prepare a writtenstatement, including a cost-benefitanalysis, for proposed and final ruleswith ‘‘Federal mandates’’ that mayresult in expenditures to State, local,and tribal governments, in the aggregate,or to the private sector, of $100 millionor more in any one year. Beforepromulgating an EPA rule for which awritten statement is needed, section 205of the UMRA generally requires EPA toidentify and consider a reasonablenumber of regulatory alternatives andadopt the least costly, most cost-effective or least burdensome alternativethat achieves the objectives of the rule.The provisions of section 205 do notapply when they are inconsistent withapplicable law. Moreover, section 205allows EPA to adopt an alternative otherthan the least costly, most cost-effectiveor least burdensome alternative if theAdministrator publishes with the finalrule an explanation why that alternativewas not adopted. Before EPA establishesany regulatory requirements that maysignificantly or uniquely affect smallgovernments, including tribalgovernments, it must have developedunder section 203 of the UMRA a small

government agency plan. The plan mustprovide for notifying potentiallyaffected small governments, enablingofficials of affected small governmentsto have meaningful and timely input inthe development of EPA regulatoryproposals with significant Federalintergovernmental mandates, andinforming, educating, and advisingsmall governments on compliance withthe regulatory requirements.

The EPA has determined that this rulecontains a Federal mandate that mayresult in expenditures of $100 million ormore for State, local, and tribalgovernments, in the aggregate, or theprivate sector in any one year.Accordingly, EPA has prepared undersection 202 of the UMRA a writtenstatement which is summarized below.

The EPA has determined that to meetthe requirements of section 110(a)(2)(D)of the Clean Air Act, States must submitSIP provisions that limit NOX emissionsto the specified amounts indicatedelsewhere in this rulemaking. The EPAis granting the affected States broaddiscretion in developing SIP controls toattain these levels. The EPA hasexamined a variety of possible,regionwide NOX emissions controls,which could form the basis for (i) Statebudgets of different levels thanproposed, as well as (ii) State packagesof control meadeveloping the budgetlevels. The EPA is soliciting commenton whether the budget levels proposedin today’s action are the most cost-effective or least burdensome alternativethat achieves the objectives of the ruleand on other alternatives (e.g., applyingdifferent levels of control in differentsubregions), if feasible, that EPA shouldexamine in developing final budgetlevels.

By today’s proposal, EPA is notdirectly establishing any regulatoryrequirements that may significantly oruniquely affect small governments,including tribal governments. Thus,EPA is not obligated to develop undersection 203 of the UMRA a smallgovernment agency plan.

Consistent with the intergovernmentalconsultation provisions of section 204 ofthe UMRA and Executive Order 12875,‘‘Enhancing the IntergovernmentalPartnership,’’ EPA has already initiatedconsultations with the governmentalentities affected by this rule. The EPAalready consulted with thesegovernmental entities extensivelyduring the OTAG process. The EPA hasreceived extensive comments fromgovernmental entities through OTAG,including specific recommendationsfrom OTAG, as described above. TheEPA has evaluated those comments andrecommendations, and has determined


1 Budget as used in this recommendation does notimply that a cap will be implemented.

2 As described in the Utility NOX ControlsRecommendation.

to propose statewide budget levelsbased on a basket of regional NOX

controls that bear some similarity tothose OTAG recommendations. TheEPA’s reasons for doing so are describedat length in this rulemaking.

Dated: October 10, 1997.Carol M. Browner,Administrator.

BILLING CODE 6560–50–P

Appendix A—References1. Ozone Transport Assessment Group

(OTAG), Policy Paper approved by the PolicyGroup on December 4, 1995.

2. National Research Council, Committeeon Tropospheric Ozone Formation andMeasurement, ‘‘Rethinking the OzoneProblem in Urban and Regional AirPollution,’’ pp. 93–107, National AcademyPress, Washington, DC, 1991.

3. Wisconsin Department of NaturalResources, ‘‘An Analysis of Measured andPredicted Concentrations Aloft of Ozone andTotal Reactive Oxides of Nitrogen in theEastern U.S. During July 1995,’’ DRAFT,January 25, 1997, Madison, WI.

4. Northeast States for Coordinated Air UseManagement, ‘‘The Long-Range Transport ofOzone and Its Precursors in the EasternUnited States,’’ March 1997, Boston, MA.

5. OTAG, ‘‘Ozone Transport AssessmentGroup Modeling Protocol,’’ Version 3.0,1996.

6. OTAG, ‘‘Ozone Transport AssessmentGroup Draft Final Report, Chapter 2 Regionaland Urban Scale Modeling,’’ 1997.

7. Sonoma Technology, Inc., ‘‘Evaluation ofthe UAM–V Model Performance in OTAGSimulations, Phase I: Summary ofPerformance Against Surface Observations,’’January 1997, STI–996120–1605–FR, SantaRosa, CA.

8. E.H. Pechan & Associates, ‘‘OTAGEmissions Inventory Development Report,’’Volumes I, II, and III: DRAFT Report, June1997, Durham, NC.

9. OTAG, ‘‘DRAFT Final Report Volume I:Executive Summary, Ozone TransportAssessment Group Air Quality and AnalysisWorkgroup.’’ June, 1997.

10. Chameides, W.L. and E.B. Cowling,‘‘The State of the Southern Oxidants Study(SOS): Policy-Relevant Findings In OzonePollution Research, 1988–1994.’’ pg. 37,January 1995.

11. Porter, P.S., S.T. Rao, E. Zalewsky, IZurbenko, R.F. Henry, and J.Y. Ku,‘‘Statistical Characteristics of Spectrally-Decomposed Ambient Ozone Time SeriesData,’’ Report to the Ozone TransportAssessment Group, 1996.

12. Environ, Inc., ‘‘Review of ExistingOzone Measurement and Modeling Studiesin the Eastern United States,’’ February 21,1996, Novato, CA.

13. Ozone Transport Commission, ‘‘1994Fall Meeting Report,’’ September 27, 1994,Newport, RI.

14. Morris, R.E., G.M. Wilson, S.B.Shepard, and K. Lee, ‘‘Ozone SourceApportionment Modeling Using the July1991 OTAG Episode for the NortheastCorridor and Lake Michigan Regions,’’ March1997, Environ, Inc., Novato, CA.

15. McNeill, D., T.W.X. Task,‘‘Photochemical Modeling Analysis of theNorthwest ‘‘Ozone Free’’ OTAG States Usingthe July 1995 OTAG Modeling Episode,’’March 1997, Alpine Geophysics, Golden, CO.

16. EPA, 1995, ‘‘National Air PollutantEmission Trends, 1990–1994,’’ EPA–454/R–95–001, October 1995.

17. U.S. Environmental Protection Agency,‘‘Nitrogen Oxides: Impacts on Public Healthand the Environment,’’ EPA–452/R–97–002,August 1997.

Appendix B—OTAG Recommendations

July 8, 1997.Ms. Mary Nichols,Assistant Administrator, Air & Radiation

Division, U.S. Environmental ProtectionAgency, 401 M Street, SW., (MC–M6101),Washington, DC 20460

Dear Ms. Nichols: The Ozone TransportAssessment Group (OTAG) has completed itswork in accordance with your memorandumof March 2, 1995. Attached please find therecommendations to the U.S. EnvironmentalProtection Agency approved by OTAG. Alsoattached are states’ and stakeholders’comments on the recommendations andidentification of the votes cast on each byeach state. The technical support documentsresulting from OTAG’s work will beforwarded as soon as they are completed.

We appreciate the technical and financialsupport that EPA has provided OTAG overthe past two years. We believe that thisunprecedented effort of dynamic interactionamong state and federal government,industry and environmental stakeholders hasdemonstrated that diverse interests can worktogether constructively on important policyissues. We encourage EPA to considerOTAG’s recommendations as it proceedswith implementation of the Clean Air Act.

Sincerely,Mary A. Gade,

Chair, Policy Group.Donald R. Schregardus,

Chair, Strategies & Controls Subgroup.Ned O. Sullivan,

Chair, Outreach & CommunicationsSubgroup.

Robert C. Shinn, Jr.,Chair, Modeling & Assessment, Subgroup.

Harold Reheis,Chair, Financial Subgroup.

Recommendation: Additional Modeling andAir Quality Analysis (Approved by thePolicy Group, June 3, 1997)

Based on the conclusions of OTAG, statesmust have the opportunity to conductadditional local and subregional modelingand air quality analyses, as well as developand propose appropriate levels and timing ofcontrols. In taking these actions, priorityshould be given to the serious and severenonattainment areas of Atlanta, LakeMichigan, and the Northeast, relative totransport. EPA has announced its intention topropose and take final action on a SIP call.States can work together and with EPAtoward completing local SIPs including theevaluation of possible local NOX disbenefits,and to build on the modeling and air qualityanalysis work of OTAG to evaluate EPA’s

proposed statewide tonnage budgets 1 in itsproposed SIP calls. The initial statewidetonnage budgets proposed by EPA may berevised or shown to be unnecessary orinsufficient through additional subregionalmodeling or air quality analyses. OTAGrecommends EPA evaluate states’ timelysubmittal of comments and subregionalmodeling regarding the proposed statewidebudgets prior to EPA’s finalizing the SIP callswithin 12 months of their proposal.

The Policy Group recognizes that NOX

controls for ozone reduction purposes havecollateral public health and environmentalbenefits, including reductions in aciddeposition, eutrophication, nitrification, fineparticle pollution and regional haze.

Recommendation: Diesel Fuel (Approved bythe Policy Group, June 3, 1997)

OTAG recommends that, by 1999, EPAshould evaluate the emission benefits andother effects, such as fuel economy, of cetaneadjustments on current technology engines,both on highway and non-road, and, ifappropriate, expeditiously adopt andimplement standards. OTAG furtherrecommends that the EPA use of existingcollaborative process developed as a result ofthe 1995 statement of principles to identifyif new diesel fuel standards are beneficial. Iffound beneficial and cost-effective, OTAGfurther recommends that EPA adopt andimplement new standards no later than 2004.

Recommendation: Gasoline (Approved bythe Policy Group May 13, 1997)

The OTAG states recommend thecontinued use of Federal ReformulatedGasoline (RFG) in the mandated and opt-inareas.

The OTAG states support state flexibilityand encourage the opt-in to the Federal RFGprogram or other fuel strategies consistentwith the Clean Air Act, including thoseattainment areas which contribute todownwind nonattainment situations orwhich choose to implement strategies toassist in preventing violations of the NationalAmbient Air Quality Standard (NAAQS) forozone.

The USEPA should adopt and implementby rule an appropriate sulfur standard tofurther reduce emissions and assist thevehicle technology/fuel system achievemaximum long term performance.

Recommendation: Vehicle EmissionInspection and Maintenance Controls(Approved by the Policy Group, June 19,1997)

• The OTAG states recommend that, whererequired by the Clean Air Act, appropriateand effective vehicle emission inspection andmaintenance (I/M) programs beimplemented. The OTAG states additionallyrecommend that states consider the adoptionof enhanced I/M programs in all urbanizedareas in the fine grid 2 with a populationgreater than 500,000.

• The OTAG states further recommendthat EPA recognize and give appropriate


credit to the state-by-state emission reductionbenefits of vehicle I/M programs and theirimpact on transport of ozone and itsprecursors.

• The OTAG states recognize the potentialeffectiveness of a vehicle on-board diagnostic(OBD) system to alert drivers of emissioncontrol system malfunctions and to ensureproper maintenance and operation of theemission control system under real worlddriving conditions. Therefore, they encourageEPA to support periodic OBD system checksas part of an effective vehicle I/M programand to provide appropriate I/M programcredit.

Recommendation: Major Modeling/AirQuality Conclusions (Approved by the PolicyGroup, June 3, 1997)

Based on OTAG modeling, the Regionaland Urban Scale Modeling and Air Quality

Analysis Workgroups have drawn severalconclusions regarding the benefits to bederived from NOX and VOC controls for allsource sectors and regarding ozone transport.Regional NOX reductions are effective inproducing ozone benefits; the more NOX

reduced, the greater the benefit. Ozonebenefits are greatest where emissionreductions are made and diminish withdistance. Elevated and low level NOX

reductions are both effective. VOC controlsare effective in reducing ozone locally andare most advantageous to urbannonattainment areas. Air quality datadocuments the widespread and pervasivenature of ozone and indicates transport ofozone. Air quality analyses also indicate thatozone aloft is carried over and transportedfrom one day to the next. Generally, the rangeof transport is longer in the North than in theSouth. Additionally, coarse grid impacts on

the fine grid may be minimal. Other relevantdocumentation of the RUSM and AQAWorkgroups’ efforts are available on theirWeb sites.

Recommendation: National Measures(Approved by the Policy Group May 13,1997)

The OTAG states recommend that theUSEPA continue to develop andexpeditiously adopt, no later than the datesindicated below, and effectively implementstringent control measures on a national basiswhich meet or exceed the emission reductionlevels as contained in the OTAG analysis.

The measures include:

Measure

Reductions assumedin the modeling Adoption

date

Start/implemen-tation datepercent 1 Tons 2, 3

Arch & Industrial Maintenance (AIM) Coatings:—Phase I ................................................................................................ 20% VOC 507 November 97 January 98/—Phase II ............................................................................................... 38% VOC 861 ...................... 2003.

Consumer/Commercial Products:—Phase I ................................................................................................ 20% VOC 886 November 97 March 98/—Phase II ............................................................................................... 30% VOC 1281 ...................... 2003.

Autobody Refinishing:—Phase I ................................................................................................ 37% VOC 281 August 97 .... January 98/—Phase II ............................................................................................... 53% VOC 391 ...................... 2003.

Reformulated Gasoline .................................................................................. 25% VOC 4 5 na ...................... 2000.(RFG) Phase II .............................................................................................. 6.8% NOX na ......................Phase II Small Engine Standards .................................................................. 43% VOC 1343 ...................... 2007.Marine Engine Standards .............................................................................. 23% VOC 398 ...................... 1998.Heavy Duty Highway 2g Standard (Equivalent to a 4g standard in 2007) ... Varies by

EngineFamily

5 na ...................... 2004.

Heavy Duty Nonroad Diesel Standard .......................................................... 37% NOX 1499 ...................... 2004.Locomotive Standard with Rebuild ................................................................ 43% NOX

10% NOX

6 na126

...................... 1997.

1 Percent reductions were applied to 1990 emissions projected to 2007.2 Tonnage reduction differences are based on 1990 emissions projected to 2007.3 Reductions from multi-phase programs are cumulative.4 For Phase II RFG, percent reductions are based only on affected emissions.5 Tonnage reductions could not be calculated for RFG and the Heavy Duty Highway 2g Standard since the effects of growth and control could

not be accounted for separately by the model used.6 The 43% reduction includes rebuilt engines; however, rebuilts were not modeled by OTAG. The modeled reduction was only 10%.

• The OTAG states encourage the USEPAto reach closure on the Tier 2 Motor VehicleStudy in recognizing the benefits of volatileorganic compound and nitrogen oxidereductions and their implication for ozoneproduction.

Recommendation: National Low EmissionVehicle (Approved by the Policy Group May13, 1997)

The OTAG states acknowledge the abilityof states to adopt the California LowEmission Vehicle Program and furtheracknowledge that the National Low EmissionVehicle Program is a voluntary program.OTAG supports and encourages theimplementation of a National Low EmissionVehicle Program.

Recommendation: Non-Utility Point SourceControls (Approved by the Policy Group,June 19, 1997)

Definitions

For purposes of this recommendation,individual medium non-utility point sourcesare defined as follows:A boiler > 100 MMBtu/hr and < 250 MMBtu/

hrA reciprocating i.c. engine > 4000 hp and <

8000 hpA turbine > 10,000 hp and < 20,000 hpAny other source > 1 ton/average summer

day and < 2 tons/average summer dayFor purposes of this recommendation,

individual large non-utility point sources aredefined as follows:A boiler ≥ 250 MMBtu/hrA reciprocating i.c. engine ≥ 8000 hpA turbine ≥ 20,000 hp

Any other source ≥ 2 tons/average summerday

Control Levels

The OTAG Policy Group recommends thatthe stringency of controls for large non-utilitypoint sources should be established in amanner equitably with utility controls. TheOTAG Policy Group recommends that RACTshould be considered for individual mediumnon-utility point sources were appropriate.

If additional modeling and air qualityanalyses are performed as specified inOTAG’s recommendation for ‘‘AdditionalModeling and Air Quality Analysis,’’ thendevelopment of final state non-utility pointsource strategies should consider saidmodeling and analyses.


3 Budget as used in this recommendation does notimply that a cap will be implemented.

Control Targets for Budget 3 CalculationPurposes

The OTAG Policy Group anticipatesUSEPA will calculate a statewide NOx

tonnage budget for each state. In calculatingthe statewide NOx tonnage budgets, theOTAG Policy Group recommends acalculation based on the following non-utility point source control targets:

Reference util-ity control level

(coal-firedpower plants)

Controltargetsfor thelarge

non-utilitypoint

sourcesector

(percent)

Control targetsfor the mediumnon-utility pointsource sector

55% (0.35 lb/MMBtu).

55 Uncontrolled.

65% (0.25 lb/MMBtu).

60 Uncontrolled.

75% (0.20 lb/MMBtu).

65 RACT.

85% (0.15 lb/MMBtu).

70 RACT.

The control targets, expressed as anemission reduction percentage, should bebased on uncontrolled emission rates. Thebudget component for non-utility pointsources is not intended to be an allocation forthe non-utility point source sector or forindividual units.

Flexibility and Relationship to OtherRequirements

The OTAG Policy Group acknowledgesthat states have flexibility in implementingthe non-utility point source strategy. Theserecommendations shall not supersede anyother more restrictive state or federalrequirement.

Recommendation: Ozone Action Days(Approved by the Policy Group, June 3,1997)

The OTAG states endorse and encouragethe development and implementation ofozone action programs to increase publicawareness of the public health and welfareissues associated with ozone air pollution.These include but are not limited to dailysummertime ozone mapping projects whichprovide ‘‘real-time’’ information to theviewer and other programs and informationto encourage participation in programs toreduce the emissions of ozone precursors.These programs may be effective in reducingpeak ozone concentrations. Theycomplement traditional control strategies forthe reduction of ozone and ozone precursors.

Recommendation: OTAG’s TechnicalAnalysis (Approved by the Policy Group,June 3, 1997)

OTAG’s goal is to ‘‘identify andrecommend a strategy to reduce transportedozone and is precursors which, incombination with other measures, willenable attainment and maintenance of thenational ambient ozone standard in the

OTAG region.’’ OTAG has performed themost comprehensive technical analysis ofozone transport ever conducted. Incooperation with the states and stakeholdersand by sharing information, OTAG hasdeveloped and produced the best and mostcomplete emissions inventory for the OTAGregion. OTAG has used UAM–V, a state-of-the-art photochemical model, to analyze thepotential impact of various control strategies.OTAG has also developed and applied newtechniques to analyze existing air qualitydata to examine the ozone problem.

Recommendation: Trading ProgramFramework (Approved by the Policy Group,June 19, 1997)

Market-based approaches are generallyrecognized as having the following benefitsin relation to traditional command andcontrol regulations: (1) reduce the cost ofcompliance; (2) create incentives for earlyreductions; (3) create incentives for emissionreductions beyond those required byregulations; (4) promote innovation; and (5)increase flexibility without resorting towaivers, exemptions and other forms ofadministrative relief.

OTAG recognizes that states have theoption to select market systems that are bestsuited to their policy purposes and airquality planning and program needs. Inanticipation of the state specific decisions,OTAG recognizes that states may choose oneof two basic approaches to implement NOx

emissions market systems.• Track One—States that elect to

implement equivalent NOx market systemswith emissions caps could be part of acommon, interstate emissions market.Designated sources would be authorized toparticipate in emissions trading. Otherstationary sources could opt-in to the marketunder specific conditions. A centralregulatory authority, such as EPA, couldadminister this multi-state NOx marketsystem.

• Track Two—States that elect toimplement NOx market systems withoutemissions caps would be part of one or morealternative emissions markets. Thesealternative markets could have severaldifferent forms starting with intra-stateemissions trading which could possibly leadto multi-state trading arrangements.Participating sources in each state would beauthorized to conduct emissions tradingconsistent with the scope of the alternativemarket system. If multiple, equivalent NOx

market systems are generated by states, thensome central entity, in consultation withEPA, could administer the multi-state NOx

market system.While OTAG recognizes that the

procedures for a cap and trade program areknown and implementable, the OTAGencourages the joint state/EPA workgroup(s)described herein to bring similar certainty tonon-cap but SIP approved trading programs.

At some point, states may be interested incross-track trading. Further developmentwork and more time is necessary todetermine whether and how this cross-tracktrading could be credibly done.Implementation of either track should not bedelayed while an approach for cross-track

trading is developed. Inter-sector tradingmight be provided for as well.

EPA review and approval of specific stateSIP revisions would be necessary for NOx

market systems from either track that aredeveloped in response to EPA’s SIP call.States would be responsible for meetingapplicable federal requirements and ensuringthat the integrity of the state’s emissionsbudget was maintained, as well as otherdesirable results from adoption to suitablemarket systems. EPA is responsible forapproving state programs that meet theapplicable federal requirements.

OTAG also recommends that a joint state/EPA Workgroup be formed to address, withappropriate stakeholder involvement, thefollowing tasks:

• Appropriate provisions forimplementing Tracks One and Two asdescribed above.

• Key design features for NOx emissionsmarket systems that could be selected byaffected states.

A series of seven design proposal papershave been developed by the Trading/Incentives Workgroup which include specificrecommendations that are incorporated inthe OTAG final report. These papers serve asa sound basis for carrying out the work ofthis joint workgroup. The following specificissues should also be addressed by the jointworkgroup:

1. Subregional modeling and air qualityanalysis should be carefully evaluated todetermine whether distance and directionshould affect how trading may take place.Appropriate mechanisms, such as tradingratios or weights, could be developed ifsignificant effects are expected.

2. Market systems should be operated andevaluated, and adjustments made as neededto reflect experience gained with tradingdynamics and any attendant air qualityimpacts.

3. Local control requirements necessary forattainment may still be utilized for specificsources.

Recommendation: Utility NOX Controls(Approved by the Policy Group, June 3,1997)

The OTAG Policy Group recommends thatthe range of utility NOX controls in the finegrid fall between Clean Air Act controls andthe less stringent of 85% reduction from the1990 rate (lb/mmBTU) or 0.15 lb/mmBTU inorder to mitigate ozone transport and assiststates in complying with the existing 120 ppbozone standard. OTAG modeling shows thatozone transport is greater in the northern tierthan in the southern tier. EPA has indicatedthat control levels are to be determined andimplemented through statewide tonnagebudgets. The statewide budget processshould be as described OTAG’srecommendation ‘‘Additional Modeling andAir Quality Analysis.’’ Control measures areto be determined and implemented by thestates. The actions set forth in this sectionmust be carried out in accordance with theClean Air Act. If trading is allowed, publicinterest stakeholders have recommended thata minimum of 10% of each state’s tonnagebudget be allocated solely to qualifying,verifiable, and new end-use energy efficiency


4 It is understood that the State of Iowa will workwith the State of Wisconsin in the development ofthe Southeast Wisconsin ozone SIP.

5 It is understood that the state of Kansas willwork with the state of Missouri in the continuedprogress of the Kansas City ozone SIP. In addition,the states of Oklahoma, Texas, Arkansas, andLouisiana will share with the state of Missouri theresults of their urban and regional scale ozonemodeling which includes boundary conditioninformation and emissions in inventory datashowing projected impacts of ozone controlprograms.

and renewable projects. The coarse gridstates which would be exempt from OTAG-related controls (all of North Dakota, SouthDakota, Nebraska, Kansas, Oklahoma, Texas,Minnesota, Iowa,4 Arkansas, Louisiana,Mississippi, and Florida, as well as thecoarse grid portions of Maine, NewHampshire, Vermont, New York, Michigan,Wisconsin, Missouri 5, Alabama, andGeorgia) will, in cooperation with EPA,periodically review their emissions, and theimpact of increases, on downwindnonattainment areas and, as appropriate, takesteps necessary to reduce such impactsincluding appropriate control measures.

Appendix C—Tables for Section II

Weight of Evidence Determination ofSignificant Contribution

TABLE II–1.—OTAG 2007 STATETOTAL NOX Emissions (tons/day)

State TotalNOX

Texas .............................................. 4026Ohio ................................................ 2871Illinois .............................................. 2535Florida ............................................. 2503Pennsylvania ................................... 2406Michigan .......................................... 2334Indiana ............................................ 2271Louisiana ......................................... 2143Tennessee ...................................... 2090Georgia ........................................... 1711New York ........................................ 1677Alabama .......................................... 1621Kentucky ......................................... 1598North Carolina ................................. 1506West Virginia ................................... 1393Virginia ............................................ 1378New Jersey ..................................... 1244Missouri ........................................... 1140Oklahoma ........................................ 1107South Carolina ................................ 1040Wisconsin ........................................ 1035Mississippi ....................................... 1012Kansas ............................................ 993

TABLE II–1.—OTAG 2007 STATETOTAL NOX Emissions (tons/day)—Continued

State TotalNOX

Maryland ......................................... 940Minnesota ....................................... 917Iowa ................................................ 782Massachusetts ................................ 701Arkansas ......................................... 643Nebraska ......................................... 411Connecticut ..................................... 362Maine .............................................. 232New Hampshire .............................. 192Delaware ......................................... 164South Dakota .................................. 140Vermont .......................................... 78Rhode Island ................................... 78North Dakota ................................... 55District of Columbia ........................ 53

TABLE II–2.—OTAG 2007 STATE NOx

Emissions Density (tons/day/1000sq. mi.)

StateEmis-sions

density

District of Columbia ........................ 771.91New Jersey ..................................... 166.53Maryland ......................................... 95.55Massachusetts ................................ 89.62Delaware ......................................... 85.09Connecticut ..................................... 74.30Rhode Island ................................... 73.76Ohio ................................................ 70.03Indiana ............................................ 63.19West Virginia ................................... 57.73Pennsylvania ................................... 53.58Tennessee ...................................... 50.79Louisiana ......................................... 48.14Florida ............................................. 46.22Illinois .............................................. 45.56Michigan .......................................... 40.97Kentucky ......................................... 40.27New York ........................................ 35.40Virginia ............................................ 34.71South Carolina ................................ 34.43Alabama .......................................... 31.92Texas .............................................. 31.42North Carolina ................................. 30.83Georgia ........................................... 29.48Mississippi ....................................... 21.42New Hampshire .............................. 21.39Kansas ............................................ 20.85Oklahoma ........................................ 20.68Wisconsin ........................................ 19.02Minnesota ....................................... 18.32

TABLE II–2.—OTAG 2007 STATE NOx

Emissions Density (tons/day/1000sq. mi.)—Continued

StateEmis-sions

density

Missouri ........................................... 16.54Iowa ................................................ 13.97Nebraska ......................................... 13.43Arkansas ......................................... 12.09Vermont .......................................... 8.42Maine .............................................. 7.49North Dakota ................................... 7.28South Dakota .................................. 5.30

TABLE II–3.—OTAG 2007 BASELINECONTROL MEASURES

UTILITY• Title IV Controls (phase 1 & 2 for all boil-

er types)• 250 Ton PSD and NSPS• RACT & NSR in non-waived nonattain-

ment areas (NAAs)NON-UTILITY POINT/OTHER AREA

• RACT at major sources in non-waiveredNAAs

• 250 Ton PSD and NSPS• CTG & Non-CTG RACT at major

sources in NAAs & in Ozone TransportRegion

OTHER AREA• Two Phases of Consumer & Commercial

Products & One Phase of ArchitecturalCoatings

• Stage 1 & 2 Petroleum Distribution Con-trols in NAAs

• Autobody, Degreasing & Dry CleaningControls in NAAs

NONROAD MOBILE• Federal Phase II Small Engine Stand-

ards• Federal Marine Engine Standards• Federal HDV (>=50 hp) Standards-Ph.1• Federal RFG II (statutory and opt-in

areas)• 9.0 RVP maximum elsewhere in OTAG

HIGHWAY MOBILE• Tier 1 LDV and HDV Standards• Federal RFG II (statutory and opt-in

areas)• High Enhanced I/M (serious and above

areas)• Low Enhanced I/M for rest of OTR• Basic I/M (mandated areas)• Clean Fuel Fleets (mandated areas)• 9.0 RVP maximum elsewhere in OTAG• On board vapor recovery


TABLE II–4a.—OTAG STRATEGY CONTROL PACKETS FOR NOX

NOX strategy packets Utility system[Mostly elevated]

Other point/area[Mixed Elevated & Non-ele-

vated]

Nonroad Mobile[Non-elevated]

Highway Mobile[Non-elevated]

Base 1 (MandatedCAA controls).

*Title IV Controls [Phase 1& 2 for all boiler types]

*250 Ton PSD and NSPS*RACT & NSR in non-

waived NAAs

*RACT at major sources innon-waivered NAAs

*250 Ton PSD and NSPS*NSR in non-waived NAAs

*Fed Phase II Small Eng.Stds

*Fed Marine Engine Stds*Fed HDV (>=50 hp) Stds-

Phase 1*Fed RFG II 4

*Tier 1 LDV and HDV Stds*Fed RFG II 4

*Enh I/M 3

*Low Enh I/M for rest ofOTR

*Basic I/M in mandatedareas

*Clean Fuel Fleets for man-dated areas

Level 0 ........................ Base 1 plus:*OTC NOX MOU (Phase II)* ‘‘9% by 99’’ ROP Meas-

ures (If substitute forVOC) 3

Base 1 plus:*‘‘9% by 99’’ ROP Meas-


Base 1 plus:*Fed Locomotive Standards

(not including rebuilds)*‘‘9% by 99’’ ROP Meas-


Base 1 plus:*National LEV*HDV 2 gm std*FTP revisions*‘‘9% by 99’’ ROP Meas-


Added NOX Controls—Level 1.

More stringent of Level 0or:

*55% reduction from 1990rate or

*rate-base of 0.35 lb/mmbtufor coal units and 0.20 lb/mmbtu for gas & oil units,whichever is less strin-gent 7

Level 0 plus:Controls rated by OTAG as

under $1000 per ton

Level 0 plus:*Fed Locomotive Stds (incl

rebuild standards) 1 [Re-places Fed LocomotiveStds (not including re-builds)]

*HD engine 4 gm Std

Level 0 plus:*High Enh I/M for LDV

(LEV-specific cutpoints) 6

[Replaces Enh I/M 3, LowEnh I/M for rest of OTR,& Basic I/M in mandatedareas]

*HDV I/M 6



(a) *65% reduction from1990 rate or

*rate-base of 0.25 lb/mmbtufor coal units and 0.20 lb/mmbtu for gas & oil units,whichever is less strin-gent 7


$1000 to $5000 per ton

Level 1 plus:*Reformed Diesel (50 ce-

tane) 2

Level 1 plus:*Fed RFG II 2 5 [Replaces

Fed RFG II 4] or Low Sul-fur Fuel (150 ppm) 2,5

*Reformed Diesel (50 ce-tane) 2

*Max I/M for LDV w/ LEV-specified cutpoints 6 [Re-places High Enh I/M forLDV (LEV-specificcutpoints).6]



(b)* 75% reduction from1990 rate or

*rate-base of 0.20 lb/mmbtufor all units, whichever isless stringent 7

Deep NOX Controls—Level 3.


*85% reduction from 1990rate or

*rate-base of 0.15 lb/mmbtufor all units, whichever isless stringent 7


over $5000 per ton

Level 2 plus:*Reformed Diesel (55 ce-

tane) 2 8 [Replaces Re-formed Diesel (50 ce-tane) 2]

Level 2 plus:*Cal RFG II 2 [Replaces

Fed FG II 2,5]*Reformed Diesel (55 ce-

tane) 2 8 [Replaces Re-formed Diesel (50 ce-tane) 2].

1 National.2 OTAG Wide or Specified.3 Serious and above areas.4 Statutory and opt-in areas.5 OTAG-Optimized fuel (e.g., low RVP, low sulfur, low olefins) was evaluated elsewhere during OTAG as an alternative.6 For all nonattainment areas & attainment MSAs/CMSAs ≤=100,000.7 Qualifications set by OTAG on the use of lb/MMBtu numbers:(1) These numbers are for initial strategy modeling purposes only. They do not reflect any recommendation form OTAG on the desired level of

reduction for these units. (2) OTAG reserves the right to do sensitivity analyses on any source in an effort to achieve a desired ozone impact.Such sources may include those that chose the lb/MMBtu option. The requirement for such analyses may exist in certain areas where the sizeand location of such a major source is critical to achieving the ozone goals. (3) The alternative lb/MMBtu limits shall not supersede an existingrequirement that is more stringent (e.g., OTC MOU or NSPS requirements).

8 OTAG evaluated California diesel separately.


TABLE II–4b.—OTAG STRATEGY CONTROL PACKETS FOR VOC

VOC strategy packets Major point sources Other point/area Nonroad mobile Highway mobile

Base 1 (MandatedCAA controls).

*CTG & Non-CTG RACT atmajor sources in NAAs &in OTC.

*New Source LAER & Off-sets for NAAs.

*Two Phases of Consumer& Commercial Products &one Phase of Architec-tural Coatings.

*Stage 1 & 2 PetroleumDistribution Controls-NAAs.

*Autobody, Degreasing &Dry Cleaning Controls inNAAs.

*Fed Phase II Small Eng.Stds.

*Fed Marine Engine Stds ...*Fed HDV (>=50 hp) Stds-

Ph. 1.*Fed RFG II4 4 ....................*9.0 RVP maximum else-

where in OTAG.

*Tier 1 LDV and HDV Stds.*Fed RFG II 4

*9.0 RVP maximum else-where in OTAG.

*Enh I/M.3*Low Enh I/M for rest of

OTR.*Basic I/M in mandated

areas.*Clean Fuel Fleets in man-

dated areas.*On board vapor recovery.

Level 0 ........................ Base 1 plus:*‘‘9% by 99’’ ROP Meas-

ures (NOX may be sub-stituted after 1996).3.

Base 1 plus:*‘‘9% by 99’’ ROP Meas-


Base 1 plus:*Fed Locomotive Standards

(not including rebuilds).*‘‘9% by 99’’ ROP Meas-


Base 1 plus:*National LEV.*HDV 2 gm std.*FTP revisions.*‘‘9% by 99’’ ROP Meas-

ures (NOX may be sub-stituted after 1996).3

Added VOC Controls-Level 1.

Level 0 plus: (No additionalcontrols).

Level 0 plus: (No additionalcontrols).

Level 0 plus: Level 0 plus:*High Enh I/M for LDV

(LEV-specific cutpoints) 6

[Replaces Enh I/M 3, LowEnh I/M for rest of OTR,& Basic I/M in mandatedareas].

*HDV I/M.6*Low RVP (6.7 psi) in non-

RFG areas 2 [Replaces9.0 RVP maximum else-where in OTAG].

Added VOC Controls-Level 2.

Level 1 plus:(a) * Apply NAA Base 1 de-

fault control assumptionsacross AA down to 100TPY sources.

Level 1 plus:(a) * Apply NAA Base 1 de-

fault control assumptionsacross AA down to 100TPY sources—Bulk Ter-minals.

Level 1 plus:*Fed RFG II 2 5 [Replaces

Fed RFG II 4].

Level 1 plus:*Maximum I/M (LEV-spe-

cific cutpoints) for LDV 6

[Replaces High Enh I/M(LEV-specificcutpoints) 3].

*Fed RFG II 2 5 [ReplacesFed RFG II 4].

Level 2a plus:(b) *10% reduction in VOC

emissions beyond level2a from major pointsources in major metro-politan NAAs.

Level 2a plus:(b) *Increased C/C Prod-

ucts limits.*Increased AIM limits ..........*Increased Autobody Refin-

ishing limits.

.............................................

Deep VOC Controls-Level 3.

Level 2 plus: (Same as 2b) Level 2 plus: (Same as 2b) Level 2 plus:*Cal RFG II 2 [Replaces

Fed RFG II 2 5].*Cal Tier II small engine std

Level 2 plus:*Cal RFG II 2 [Replaces

Fed RFG II 2 5].

1 National.2 OTAG Wide or Specified.3 Serious and above areas.4 Statutory and opt-in areas.5 OTAG-Optimized fuel (e.g., low RVP, low sulfur, low olefins) was evaluated elsewhere during OTAG as an alternative.6 For all nonattainment areas & attainment MSAs/CMSAs >=100,000.

TABLE II–5a.—ROUND 1 AND 2 CONTROL LEVELS BY EMISSIONS SECTOR

OTAG round 1 & round 2 control levels

Run

PointNonroad Other area Motor vehicle1

Utility NOX

Nonutility

NOX VOC NOX VOC NOX VOCNOX VOC

Round 1:1 ...................................... 0 0 0 0 0 0 0 0 02 ...................................... 3 3 3 3 3 3 3 3 33 ...................................... 3 0 0 0 0 0 0 0 04b .................................... 0 3 0 3 3 3 3 3 3


TABLE II–5a.—ROUND 1 AND 2 CONTROL LEVELS BY EMISSIONS SECTOR—Continued

OTAG round 1 & round 2 control levels

Run

PointNonroad Other area Motor vehicle1

Utility NOX

Nonutility

NOX VOC NOX VOC NOX VOCNOX VOC

Round 2:5 ...................................... 3 1 0 1 1 1 1 0 06 ...................................... 2b 1 0 1 1 1 1 0 07 ...................................... 2a 1 0 1 1 1 1 0 08 ...................................... 1 1 0 1 1 1 1 0 09 ...................................... 3 2 0 2 2 2 2 1.5 1.510 .................................... 2b 2 0 2 2 2 2 1.5 1.511 .................................... 2a 2 0 2 2 2 2 1.5 1.512 .................................... 1 2 0 2 2 2 2 1.5 1.5

1 Motor vehicle emissions level 1.5 includes enhanced I/M in all 1-hr nonattainment areas and in all attainment Metropolitan Statistical Areasand Consolidated Metropolitan Statistical Areas with population >=500,000.

TABLE II–5b.—DOMAINWIDE ROUND 1 AND 2 EMISSION TOTALS BY SECTOR

Emissions totals (tons/day)

Run

PointNonroad Other Area Motor vehicle Total

UtilityNOX

Nonutility

NOX VOC NOX VOC NOX VOC NOX VOCNOX VOC

Round 1:1990 ...................... 20144 8600 8340 7390 6500 3500 18300 16619 15731 56253 48871Base1b .................. 14500 10330 5557 7427 6027 4460 17692 14000 9400 50717 386761 ............................ 13970 10215 5557 7315 6027 4460 17637 12400 8700 48360 379212 ............................ 5203 4969 4217 5725 5854 4460 16912 9200 4500 29557 314833 ............................ 5203 9626 5557 7315 6027 4460 17637 12400 8700 39004 379214b .......................... 13946 5562 5557 5725 5854 4460 16912 9200 4500 38893 32823

Round 2:1990 ...................... 21019 7709 8304 7567 6541 3238 17806 16619 15731 56152 48382Base1c .................. 15441 8459 5719 7506 6039 4202 17076 14000 9400 49608 382345 ............................ 5348 6828 5712 6453 6039 4202 17076 12400 8700 35231 375276 ............................ 7383 6828 5712 6453 6039 4202 17076 12400 8700 37266 375277 ............................ 9249 6828 5712 6453 6039 4202 17076 12400 8700 39132 375278 ............................ 11425 6828 5712 6453 6039 4202 17076 12400 8700 41308 375279 ............................ 5348 5247 5712 6381 5989 4202 15757 10650 5500 31828 3295810 .......................... 7383 5247 5712 6381 5989 4202 15757 10650 5500 33863 3295811 .......................... 9249 5247 5712 6381 5989 4202 15757 10650 5500 35729 3295812 .......................... 11425 5247 5712 6381 5989 4202 15757 10650 5500 37905 32958


TABLE II–6.—RESULTS OF ROUND 1 AND ROUND 2 STRATEGY MODELING

Round-1 Results:Run 1 (Level 0)

—Little additional benefit on regional scale—Benefits occur mostly in Northeast

Run 2 (Level 3)—Large areas of lower ozone; decreases of 10–40 ppb—Level 3 control will not provide for attainment throughout the eastern U.S.

Run 3 (Level 3 Elevated NOX) and Run 4b (Level 3 Low-Level NOX)—Both elevated and low-level control effective in lowering ozone on regional scale—Relative effectiveness varies by region and episode (e.g., elevated [utility] NOX more effective in Midwest, low-level NOX more effective

in Northeast and Southeast)All Strategies

—For all strategies, there are ozone increases in some areas on some days—For all strategies, the 8-hour concentration changes are directionally consistent with the 1-hour concentration changes

Round-2 Results:The Round-2 strategy emission/ozone reductions are all within the range of Run 1 (Round-1) and Run 2 (Round-1)—More emissions reductions, more ozone reductions—Run 9 (maximum Round-2 emissions reduction) provides a little less ozone benefit than Run 2—Run 9 will not be sufficient to provide for attainment of the current 1-hour ozone NAAQS throughout the Eastern U.S.—Elevated and low-level NOX reductions are both effective in lowering ozone (relative effectiveness varies by episode)—Elevated and low-level NOX reductions are cumulative, but may not be synergistic (i.e., appear to act independently)—Run 8 (minimum Round-2 emissions reduction) show ozone increases in some areas on some days; note, increases do not seem to get

any worse by Run 9 (maximum Round-2 emissions reduction)—All Round-2 strategies show ozone decrease in areas and on days with high ozone, and ozone increases in areas and on days with low

ozone—Magnitude and spatial extent of 8-hour concentration differences are similar to 1-hour concentration differences

TABLE II–7.—ROUND 3 CONTROL LEVELS BY GEOGRAPHIC ZONE 1

Source category Control level

Nonroad/Area Sources ....... Level 2.Point Source VOC .............. Level 0.Highway Vehicles ............... Level 1.3 (same as Level 2, except high enhanced I/M is applied to all nonattainment areas and attainment Metro-

politan Statistical Areas/Consolidated Metropolitan Statistical Areas with population >= 500,000 in the ‘‘FineGrid’’ portion of the OTAG region only)

Non-utility point sourceNOX

Linked to the level of utility controls

Utility Non-Utility

Level 0 or ......................................................................... Level 1 for sources >250 MMBtu/hr.Level 1 ............................................................................. Level 0 for sources <250 MMBtu/hr.Level 2a ........................................................................... Level 1.Level 2b or ....................................................................... Level 2 for sources >250 MMBtu/hr.Level 3 ............................................................................. Level 1 for sources <250 MMBtu/hr.

1 The control levels for nonroad sources, area sources, point source VOC, and highway vehicles were applied throughout the OTAG region inall of the Round 3 runs. Utility and non-utility NOx control levels varied geographically.

TABLE II–7.—(CONTINUED)

Round 3 utility control levels

Run #Chicago/At-lanta/North-east NAAs

Zone III North-east

Zone I Mid-west

Zone V N.Georgia

Zone II OhioValley

Zone IVSoutheast Coarse grid Utility NOX

emissions

A ................... 2b .................. 1 .................... 1 .................... 1 .................... 1 .................... 1 .................... 0 1,822,915B ................... 2a .................. 2a .................. 2a .................. 2a .................. 1 .................... 1 .................... 0 1,767,341C .................. 2b .................. 2b .................. 2b .................. 2b .................. 1 .................... 1 .................... 0 1,678,866D .................. 2b .................. 2b .................. 2b .................. 2b .................. 2a .................. 1 .................... 0 1,581,554E ................... 2b .................. 2b .................. 2b .................. 2b .................. 2a .................. 2a .................. 0 1,528,004F ................... 2a/2b ............. 2b .................. 2a .................. 2a .................. 2a .................. 2a .................. 0 1,595,237G .................. 2b .................. 2b .................. 2b .................. 2b .................. 2b .................. 2a .................. 0 1,433,002H .................. 2b .................. 2b .................. 2b .................. 2b .................. 2b .................. 2b .................. 0 1,392,877I1 .................. 3 .................... 3 .................... 3 .................... 3 .................... 3 .................... 2b .................. 0 1,199,268I .................... 3 .................... 3 .................... 3 .................... 3 .................... 3 .................... 2b .................. 1 1,019,578

Level 0—OTC MOU Phase II/Acid Rain.Level 1—0.35 lb/MMBtu or 55% rate reduction from 1990.Level 2a—0.25 lb/MMBtu or 65% rate reduction from 1990.Level 2b—0.20 lb/MMBtu or 75% rate reduction from 1990.Level 3—0.15 lb/MMBtu or 85% rate reduction from 1990.


TABLE II–8a.—COUNTIES VIOLATINGTHE 1-HR OZONE NAAQS BASEDON 1993–1995 AMBIENT AIR QUAL-ITY MONITORING DATA

State County

Alabama .................... Jefferson.Alabama .................... Shelby.Connecticut ............... Hartford.Connecticut ............... New Haven.Connecticut ............... Middlesex.Connecticut ............... Litchfield.Connecticut ............... New London.Connecticut ............... Fairfield.Connecticut ............... Tolland.Delaware ................... New Castle.Delaware ................... Kent.District of Columbia ... Washington.Georgia ..................... Rockdale.Georgia ..................... Douglas.Georgia ..................... De Kalb.Georgia ..................... Fulton.Illinois ........................ Cook.Illinois ........................ Madison.Indiana ...................... La Porte.Indiana ...................... Warrick.Indiana ...................... Clark.Louisiana ................... Lafourche.Louisiana ................... Ascension.Louisiana ................... Iberville.Louisiana ................... East Baton Rouge.Maine ........................ York.Maine ........................ Sagadahoc.Maryland ................... Prince Georges.Maryland ................... Anne Arundel.Maryland ................... Harford.Maryland ................... Cecil.Maryland ................... Baltimore City.Maryland ................... Baltimore.Massachusetts .......... Worcester.Massachusetts .......... Middlesex.Massachusetts .......... Hampden.Massachusetts .......... Hampshire.Michigan .................... Allegan.Michigan .................... Macomb.Michigan .................... St Clair.Michigan .................... Mason.Michigan .................... Muskegon.Missouri ..................... St Louis.Missouri ..................... Clay.Missouri ..................... St Charles.Missouri ..................... Jefferson.New Hampshire ........ Rockingham.New Jersey ............... Camden.New Jersey ............... Monmouth.New Jersey ............... Middlesex.New Jersey ............... Ocean.New Jersey ............... Mercer.New Jersey ............... Hudson.New Jersey ............... Gloucester.New York .................. Westchester.New York .................. Putnam.New York .................. Suffolk.New York .................. Queens.New York .................. Kings.New York .................. Richmond.Ohio ........................... Warren.Pennsylvania ............. Philadelphia.Pennsylvania ............. Montgomery.Pennsylvania ............. Bucks.Pennsylvania ............. Delaware.Pennsylvania ............. Allegheny.Rhode Island ............. Kent.Rhode Island ............. Providence.

TABLE II–8a.—COUNTIES VIOLATINGTHE 1-HR OZONE NAAQS BASEDON 1993–1995 AMBIENT AIR QUAL-ITY MONITORING DATA—Continued

State County

Tennessee ................ Shelby.Texas ........................ Jefferson.Texas ........................ Harris.Texas ........................ Gregg.Texas ........................ Dallas.Texas ........................ Galveston.Texas ........................ Brazoria.Texas ........................ Tarrant.Texas ........................ Collin.Texas ........................ Denton.Virginia ...................... Arlington.Virginia ...................... Fairfax.Wisconsin .................. Manitowoc.Wisconsin .................. Ozaukee.Wisconsin .................. Milwaukee.Wisconsin .................. Kenosha.

TABLE II–8b.—COUNTIES VIOLATINGTHE 8-HR OZONE NAAQS BASEDON 1993–1995 AMBIENT AIR QUAL-ITY MONITORING DATA

Alabama .................... Clay.Alabama .................... Shelby.Alabama .................... Madison.Alabama .................... Jefferson.Arkansas ................... Crittenden.Connecticut ............... New London.Connecticut ............... Tolland.Connecticut ............... New Haven.Connecticut ............... Hartford.Connecticut ............... Middlesex.Connecticut ............... Litchfield.Connecticut ............... Fairfield.Delaware ................... New Castle.Delaware ................... Kent.Delaware ................... Sussex.District of Columbia ... Washington.Florida ....................... Escambia.Georgia ..................... Rockdale.Georgia ..................... Fulton.Georgia ..................... Gwinnett.Georgia ..................... De Kalb.Georgia ..................... Douglas.Georgia ..................... Richmond.Illinois ........................ Madison.Illinois ........................ Cook.Illinois ........................ Kane.Illinois ........................ Lake.Indiana ...................... Porter.Indiana ...................... Hancock.Indiana ...................... Marion.Indiana ...................... La Porte.Indiana ...................... Vanderburgh.Indiana ...................... Floyd.Indiana ...................... Lake.Indiana ...................... Hamilton.Indiana ...................... Allen.Indiana ...................... Warrick.Indiana ...................... Tippecanoe.Indiana ...................... Clark.Indiana ...................... Madison.Indiana ...................... Kosciusko.Indiana ...................... St Joseph.Kentucky ................... Fayette.

TABLE II–8b.—COUNTIES VIOLATINGTHE 8-HR OZONE NAAQS BASEDON 1993–1995 AMBIENT AIR QUAL-ITY MONITORING DATA—Continued

Kentucky ................... Greenup.Kentucky ................... Hancock.Kentucky ................... Livingston.Kentucky ................... Campbell.Kentucky ................... Christian.Kentucky ................... Lawrence.Kentucky ................... Scott.Kentucky ................... Oldham.Kentucky ................... Boyd.Kentucky ................... Henderson.Kentucky ................... Jefferson.Kentucky ................... Kenton.Kentucky ................... Bullitt.Kentucky ................... Daviess.Kentucky ................... McLean.Kentucky ................... Hardin.Louisiana ................... Calcasieu.Louisiana ................... Livingston.Louisiana ................... Ascension.Louisiana ................... Iberville.Louisiana ................... Lafayette.Louisiana ................... East Baton Rouge.Louisiana ................... Lafourche.Maine ........................ Knox.Maine ........................ Sagadahoc.Maine ........................ York.Maine ........................ Cumberland.Maryland ................... Kent.Maryland ................... Baltimore City.Maryland ................... Charles.Maryland ................... Prince Georges.Maryland ................... Anne Arundel.Maryland ................... Montgomery.Maryland ................... Baltimore.Maryland ................... Cecil.Maryland ................... Harford.Maryland ................... Carroll.Massachusetts .......... Middlesex.Massachusetts .......... Barnstable.Massachusetts .......... Hampden.Massachusetts .......... Hampshire.Massachusetts .......... Essex.Massachusetts .......... Bristol.Massachusetts .......... Worcester.Michigan .................... Benzie.Michigan .................... Berrien.Michigan .................... Kent.Michigan .................... Macomb.Michigan .................... Cass.Michigan .................... Muskegon.Michigan .................... Wayne.Michigan .................... Mason.Michigan .................... Lenawee.Michigan .................... Allegan.Michigan .................... St Clair.Mississippi ................. Hancock.Missouri ..................... St Charles.Missouri ..................... St Louis.Missouri ..................... Clay.Missouri ..................... Jefferson.New Hampshire ........ Rockingham.New Hampshire ........ Hillsborough.New Jersey ............... Camden.New Jersey ............... Mercer.New Jersey ............... Gloucester.New Jersey ............... Hudson.New Jersey ............... Ocean.New Jersey ............... Atlantic.



New Jersey ............... Morris.New Jersey ............... Middlesex.New Jersey ............... Bergen.New Jersey ............... Hunterdon.New Jersey ............... Monmouth.New Jersey ............... Union.New Jersey ............... Cumberland.New Jersey ............... Essex.New York .................. Dutchess.New York .................. Essex.New York .................. Richmond.New York .................. Orange.New York .................. Queens.New York .................. Putnam.New York .................. Niagara.New York .................. Kings.New York .................. Suffolk.New York .................. Jefferson.New York .................. Westchester.New York .................. Bronx.New York .................. Wayne.North Carolina ........... Wake.North Carolina ........... Northampton.North Carolina ........... Lincoln.North Carolina ........... Haywood.North Carolina ........... Granville.North Carolina ........... Guilford.North Carolina ........... Yancey.North Carolina ........... Forsyth.North Carolina ........... Caswell.North Carolina ........... Franklin.North Carolina ........... Chatham.North Carolina ........... Cumberland.North Carolina ........... Durham.North Carolina ........... Rowan.North Carolina ........... Mecklenburg.North Carolina ........... Johnston.Ohio ........................... Lawrence.Ohio ........................... Franklin.Ohio ........................... Logan.Ohio ........................... Hamilton.Ohio ........................... Jefferson.Ohio ........................... Medina.Ohio ........................... Portage.Ohio ........................... Summit.Ohio ........................... Mahoning.


Ohio ........................... Clermont.Ohio ........................... Cuyahoga.Ohio ........................... Trumbull.Ohio ........................... Ashtabula.Ohio ........................... Knox.Ohio ........................... Madison.Ohio ........................... Lake.Ohio ........................... Allen.Ohio ........................... Washington.Ohio ........................... Clinton.Ohio ........................... Licking.Ohio ........................... Stark.Ohio ........................... Lucas.Ohio ........................... Clark.Ohio ........................... Butler.Ohio ........................... Montgomery.Ohio ........................... Warren.Oklahoma .................. Tulsa.Pennsylvania ............. Washington.Pennsylvania ............. Erie.Pennsylvania ............. Philadelphia.Pennsylvania ............. Bucks.Pennsylvania ............. Northampton.Pennsylvania ............. Lehigh.Pennsylvania ............. York.Pennsylvania ............. Beaver.Pennsylvania ............. Allegheny.Pennsylvania ............. Blair.Pennsylvania ............. Lancaster.Pennsylvania ............. Cambria.Pennsylvania ............. Delaware.Pennsylvania ............. Luzerne.Pennsylvania ............. Berks.Pennsylvania ............. Perry.Pennsylvania ............. Mercer.Pennsylvania ............. Lackawanna.Pennsylvania ............. Westmoreland.Pennsylvania ............. Dauphin.Pennsylvania ............. Montgomery.Rhode Island ............. Kent.Rhode Island ProvidenceSouth Carolina .......... Richland.South Carolina .......... Anderson.South Carolina .......... Chester.South Carolina .......... York.Tennessee ................ Blount.


Tennessee ................ Hamilton.Tennessee ................ Sullivan.Tennessee ................ Dickson.Tennessee ................ Sevier.Tennessee ................ Sumner.Tennessee ................ Knox.Tennessee ................ Shelby.Tennessee ................ Williamson.Tennessee ................ Madison.Tennessee ................ Anderson.Tennessee ................ Jefferson.Texas ........................ Harris.Texas ........................ Smith.Texas ........................ Jefferson.Texas ........................ Brazoria.Texas ........................ Orange.Texas ........................ Tarrant.Texas ........................ Dallas.Texas ........................ Galveston.Texas ........................ Denton.Texas ........................ Gregg.Texas ........................ Collin.Virginia ...................... Caroline.Virginia ...................... Hanover.Virginia ...................... Fairfax.Virginia ...................... Chesterfield.Virginia ...................... Prince William.Virginia ...................... Alexandria City.Virginia ...................... Arlington.Virginia ...................... Hampton City.Virginia ...................... Henrico.Virginia ...................... Charles City.Virginia ...................... Suffolk City.Virginia ...................... Stafford.West Virginia ............. Cabell.West Virginia ............. Wood.Wisconsin .................. Racine.Wisconsin .................. Outagamie.Wisconsin .................. Ozaukee.Wisconsin .................. Sheboygan.Wisconsin .................. Milwaukee.Wisconsin .................. Kewaunee.Wisconsin .................. Kenosha.Wisconsin .................. Door.Wisconsin .................. Manitowoc.

TABLE II–9a.—SUMMARY OF AIR QUALITY CONTRIBUTIONS TO DOWNWIND NONATTAINMENT, FOR SUBREGIONS 1–6.

Approach 1 Approach 2 Approach 3 Approach 4

1 hr-violating co. 1 Hr-all grid cells 8 hr-violating co. 8 Hr-all grid cells

No.impacts No. States No.

impacts No. States No.impacts No. States No.

impacts No. States

SubRegion 1:2–5 ppb ...................... 70 4 102 7 80 8 180 105–10 ppb .................... 0 0 14 2 21 2 29 310–15 ppb .................. 0 0 0 0 1 1 5 115–20 ppb .................. 0 0 0 0 6 1 11 120–25 ppb .................. 0 0 0 0 5 1 10 1>25 ppb ...................... 0 0 0 0 1 1 1 1

SubRegion 2:2–5 ppb ...................... 193 8 362 14 239 16 432 165–10 ppb .................... 38 5 93 9 37 5 101 610–15 ppb .................. 0 0 23 6 10 2 15 215–20 ppb .................. 0 0 6 2 2 1 6 2


TABLE II–9a.—SUMMARY OF AIR QUALITY CONTRIBUTIONS TO DOWNWIND NONATTAINMENT, FOR SUBREGIONS 1–6.—Continued


1 hr-violating co. 1 Hr-all grid cells 8 hr-violating co. 8 Hr-all grid cells

No.impacts No. States No.

impacts No. States No.impacts No. States No.

impacts No. States

20–25 ppb .................. 0 0 1 1 5 1 6 2>25 ppb ...................... 0 0 0 0 1 1 1 1





TABLE II–9b. SUMMARY OF AIR QUALITY CONTRIBUTIONS TO DOWNWIND NONATTAINMENT, FOR SUBREGIONS 7–12


1 Hr-violating co. 1 Hr-all grid cells 8 Hr-violating co. 8 Hr-all grid cells

Number im-pacts

NumberStates

Number im-pacts

NumberStates

Number im-pacts

NumberStates

Number im-pacts

NumberStates

SubRegion 7:2–5 ppb ...................... 114 6 249 12 178 9 315 105–10 ppb .................... 113 4 211 8 154 7 233 710–15 ppb .................. 50 4 90 6 52 4 87 415–20 ppb .................. 21 4 47 4 15 2 35 220–25 ppb .................. 8 2 20 2 8 1 12 1> 25 ppb ..................... 19 2 65 2 8 1 35 1



SubRegion 10:2–5 ppb ...................... 0 0 1 1 13 2 24 35–10 ppb .................... 0 0 0 0 4 1 4 110–15 ppb .................. 0 0 0 0 0 0 0 015–20 ppb .................. 0 0 0 0 0 0 0 0


TABLE II–9b. SUMMARY OF AIR QUALITY CONTRIBUTIONS TO DOWNWIND NONATTAINMENT, FOR SUBREGIONS 7–12—Continued


1 Hr-violating co. 1 Hr-all grid cells 8 Hr-violating co. 8 Hr-all grid cells

Number im-pacts

NumberStates

Number im-pacts

NumberStates

Number im-pacts

NumberStates

Number im-pacts

NumberStates

20–25 ppb .................. 0 0 0 0 0 0 0 0> 25 ppb ..................... 0 0 0 0 0 0 0 0



TABLE II–10.—NUMBER OF IMPACTS IN EACH ‘‘DOWNWIND’’ STATE,1 BY IMPACT CONCENTRATION RANGE FOR EACHSUBREGION—APPROACH 1: 1-HR ‘‘VIOLATING COUNTIES’’

Number of Impacts from SubRegion 1

Impacts (ppb): AR LA TX OK KS NE SD ND MN

2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0

IA MO WI IL IN MI OH KY WV

2–5 ........................ N.A. 0 N.A. N.A. N.A. 0 0 0 05–10 ...................... N.A. 0 N.A. N.A. N.A. 0 0 0 010–15 .................... N.A. 0 N.A. N.A. N.A. 0 0 0 015–20 .................... N.A. 0 N.A. N.A. N.A. 0 0 0 020–25 .................... N.A. 0 N.A. N.A. N.A. 0 0 0 0>25 ........................ N.A. 0 N.A. N.A. N.A. 0 0 0 0

TN MS AL GA FL SC NC VA DC

2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0

MD DE PA NJ NY CT RI MA VT NH ME

2–5 ........................ 22 0 0 7 20 21 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0 0 0



2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 0


TABLE II–10.—NUMBER OF IMPACTS IN EACH ‘‘DOWNWIND’’ STATE,1 BY IMPACT CONCENTRATION RANGE FOR EACHSUBREGION—APPROACH 1: 1-HR ‘‘VIOLATING COUNTIES’’—Continued

20–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 N.A. N.A. N.A. 0 05–10 ...................... 0 0 0 0 N.A. N.A. N.A. 0 010–15 .................... 0 0 0 0 N.A. N.A. N.A. 0 015–20 .................... 0 0 0 0 N.A. N.A. N.A. 0 020–25 .................... 0 0 0 0 N.A. N.A. N.A. 0 0>25 ........................ 0 0 0 0 N.A. N.A. N.A. 0 0


2–5 ........................ 0 0 0 0 0 0 0 5 05–10 ...................... 0 0 0 0 0 0 0 2 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 23 0 1 36 47 65 3 13 0 0 05–10 ...................... 23 0 0 4 6 3 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0 0 0



2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 19 15–10 ...................... 0 0 0 0 0 0 0 19 110–15 .................... 0 0 0 0 0 0 0 1 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 43 N.A. N.A. 8 N.A. 74 3 17 0 4 75–10 ...................... 47 N.A. N.A. 33 N.A. 78 3 6 0 0 010–15 .................... 19 N.A. N.A. 34 N.A. 13 0 0 0 0 015–20 .................... 4 N.A. N.A. 21 N.A. 2 0 0 0 0 020–25 .................... 0 N.A. N.A. 5 N.A. 0 0 0 0 0 0>25 ........................ 0 N.A. N.A. 3 N.A. 0 0 0 0 0 0



2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 0



10–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 1 N.A. N.A. N.A. N.A. N.A. 0 1 0 8 05–10 ...................... 0 N.A. N.A. N.A. N.A. N.A. 0 9 0 1 210–15 .................... 0 N.A. N.A. N.A. N.A. N.A. 0 4 0 11 1515–20 .................... 0 N.A. N.A. N.A. N.A. N.A. 0 4 0 3 020–25 .................... 0 N.A. N.A. N.A. N.A. N.A. 0 3 0 1 0>25 ........................ 0 N.A. N.A. N.A. N.A. N.A. 6 30 0 1 0



2–5 ........................ 0 0 0 0 0 0 0 0 05–1 ........................ 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–2 ...................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 N.A. 0 N.A. N.A. 11 0 N.A. 05–10 ...................... 0 N.A. 0 N.A. N.A. 4 0 N.A. 010–15 .................... 0 N.A. 0 N.A. N.A. 3 0 N.A. 015–20 .................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 020–25 .................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 0>25 ........................ 0 N.A. 0 N.A. N.A. 0 0 N.A. 0


2–5 ........................ N.A. 0 4 10 0 0 0 0 05–10 ...................... N.A. 0 0 2 0 0 0 0 010–15 .................... N.A. 0 2 3 0 0 0 0 015–20 .................... N.A. 0 1 2 0 0 0 0 020–25 .................... N.A. 0 0 0 0 0 0 0 0>25 ........................ N.A. 0 0 0 0 0 0 0 0


2–5 ........................ 8 0 2 10 6 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0 0 0





2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020—25 ................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 N.A. 0 N.A. N.A. N.A.5–10 ...................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.10–15 .................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.15–20 .................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.20–25 .................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.>25 ........................ 0 0 0 0 N.A. 0 N.A. N.A. N.A.


2–5 ........................ N.A. 0 0 0 0 0 0 N.A. 05–10 ...................... N.A. 0 0 0 0 0 0 N.A. 110–15 .................... N.A. 0 0 0 0 0 0 N.A. 015–20 .................... N.A. 0 0 0 0 0 0 N.A. 020–25 .................... N.A. 0 0 0 0 0 0 N.A. 0>25 ........................ N.A. 0 0 0 0 0 0 N.A. 0


2–5 ........................ 6 4 4 26 41 4 0 0 0 0 05–10 ...................... 52 6 4 32 16 9 2 0 0 0 010–15 .................... 17 0 2 2 4 0 0 0 0 0 015–20 .................... 2 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 4 0 0 0 0 0 0 0 0



2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 N.A.5–10 ...................... 0 0 0 0 0 0 0 0 N.A.10–15 .................... 0 0 0 0 0 0 0 0 N.A.15–20 .................... 0 0 0 0 0 0 0 0 N.A.20–25 .................... 0 0 0 0 0 0 0 0 N.A.>25 ........................ 0 0 0 0 0 0 0 0 N.A.


2–5 ........................ 0 0 0 0 0 0 N.A. N.A. N.A.5–10 ...................... 0 0 0 0 0 0 N.A. N.A. N.A.10–15 .................... 0 0 0 0 0 0 N.A. N.A. N.A.15–20 .................... 0 0 0 0 0 0 N.A. N.A. N.A.20–25 .................... 0 0 0 0 0 0 N.A. N.A. N.A.>25 ........................ 0 0 0 0 0 0 N.A. N.A. N.A.


2–5 ........................ N.A. N.A. 3 17 30 50 2 12 0 0 05–10 ...................... N.A. N.A. 2 28 52 31 0 0 0 0 010–15 .................... N.A. N.A. 13 14 15 8 0 0 0 0 015–20 .................... N.A. N.A. 11 4 4 2 0 0 0 0 020–25 .................... N.A. N.A. 2 6 0 0 0 0 0 0 0>25 ........................ N.A. N.A. 7 12 0 0 0 0 0 0 0





2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 2 0 2 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 3 0 17 N.A. 0 N.A. N.A. 0 05–10 ...................... 0 0 0 N.A. 0 N.A. N.A. 0 010–15 .................... 0 0 0 N.A. 0 N.A. N.A. 0 015–20 .................... 0 0 1 N.A. 0 N.A. N.A. 0 020–25 .................... 0 0 0 N.A. 0 N.A. N.A. 0 0>25 ........................ 0 0 0 N.A. 0 N.A. N.A. 0 0


2–5 ........................ 0 0 4 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0 0 0



2–5 ........................ N.A. 10 0 0 0 0 0 0 05–10 ...................... N.A. 0 0 0 0 0 0 0 010–15 .................... N.A. 0 0 0 0 0 0 0 015–20 .................... N.A. 0 0 0 0 0 0 0 020–25 .................... N.A. 0 0 0 0 0 0 0 0>25 ........................ N.A. 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 1 0 0 0 0 05–10 ...................... 0 2 0 1 1 0 0 0 010–15 .................... 0 0 0 0 4 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 05–10 ...................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 010–15 .................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 015–20 .................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 020–25 .................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 0>25 ........................ N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0



>25 ........................ 0 0 0 0 0 0 0 0 0 0 0



2–5 ........................ 0 N.A. 0 0 0 0 0 0 05–10 ...................... 0 N.A. 0 0 0 0 0 0 010–15 .................... 0 N.A. 0 0 0 0 0 0 015–20 .................... 0 N.A. 0 0 0 0 0 0 020–25 .................... 0 N.A. 0 0 0 0 0 0 0>25 ........................ 0 N.A. 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 N.A. N.A. N.A. N.A. 0 0 0 05–10 ...................... 0 N.A. N.A. N.A. N.A. 0 0 0 010–15 .................... 0 N.A. N.A. N.A. N.A. 0 0 0 015–20 .................... 0 N.A. N.A. N.A. N.A. 0 0 0 020–25 .................... 0 N.A. N.A. N.A. N.A. 0 0 0 0>25 ........................ 0 N.A. N.A. N.A. N.A. 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0 0 0



2–5 ........................ N.A. N.A. N.A. N.A. 0 0 0 0 05–10 ...................... N.A. N.A. N.A. N.A. 0 0 0 0 010–15 .................... N.A. N.A. N.A. N.A. 0 0 0 0 015–20 .................... N.A. N.A. N.A. N.A. 0 0 0 0 020–25 .................... N.A. N.A. N.A. N.A. 0 0 0 0 0>25 ........................ N.A. N.A. N.A. N.A. 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 4 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 7 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 0 0 0



15–20 .................... 0 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0 0 0


Impacts (ppb): AR LA TX OK KS NE SD ND oi0MN

2–5 ........................ 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.5–10 ...................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.10–15 .................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.15–20 .................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.20–25 .................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.>25 ........................ 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.


2–5 ........................ N.A. N.A. N.A. 5 0 8 0 0 05–10 ...................... N.A. N.A. N.A. 0 0 11 0 0 010–15 .................... N.A. N.A. N.A. 0 0 0 0 0 015–20 .................... N.A. N.A. N.A. 0 0 0 0 0 020–25 .................... N.A. N.A. N.A. 0 0 0 0 0 0>25 ........................ N.A. N.A. N.A. 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 05–1 ........................ 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0


2–5 ........................ 0 0 0 0 0 0 0 0 0 0 05–10 ...................... 0 0 0 0 0 0 0 0 0 0 010–15 .................... 0 0 0 0 0 0 0 0 0 0 015–20 .................... 0 0 0 0 0 0 0 0 0 0 020–25 .................... 0 0 0 0 0 0 0 0 0 0 0>25 ........................ 0 0 0 0 0 0 0 0 0 0 0

1 N.A. (Not Applicable) indicates that all or major portions of these States are part of the subregion and thus, are not considered as being‘‘downwind’’.

TABLE II–11.—NUMBER OF IMPACTS IN EACH ‘‘DOWNWIND’’ STATE,1 2 BY IMPACT CONCENTRATION RANGE FOR EACHSUBREGION—APPROACH 2: 1-HR ‘‘ALL GRID CELLS’’


Impact (ppb): AR LA TX OK KS NE SD ND MN

2–5 .......................................... 0 0 0 0 0 0 0 2 45–10 ........................................ 0 0 0 0 0 0 22 4 210–15 ...................................... 0 0 0 0 0 0 1 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... N.A. 0 N.A. N.A. N.A. 1 2 0 15–10 ........................................ N.A. 0 N.A. N.A. N.A. 6 8 0 010–15 ...................................... N.A. 0 N.A. N.A. N.A. 0 0 0 015–20 ...................................... N.A. 0 N.A. N.A. N.A. 0 0 0 020–25 ...................................... N.A. 0 N.A. N.A. N.A. 0 0 0 0>25 .......................................... N.A. 0 N.A. N.A. N.A. 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0


TABLE II–11.—NUMBER OF IMPACTS IN EACH ‘‘DOWNWIND’’ STATE,1 2 BY IMPACT CONCENTRATION RANGE FOR EACHSUBREGION—APPROACH 2: 1-HR ‘‘ALL GRID CELLS’’—Continued

>25 .......................................... 0 0 0 0 0 0 0 0 0

MD DE PA NJ NY CT RI MA VT

2–5 .......................................... 24 0 0 16 35 23 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0

NH ME blank LM LS LH LE LC LO

2–5 .......................................... 0 0 0 0 0 0 0 2 45–10 ........................................ 0 0 0 0 0 0 22 4 210–15 ...................................... 0 0 0 0 0 0 1 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 N.A. N.A. N.A. 3 135–10 ........................................ 0 0 0 0 N.A. N.A. N.A. 0 1410–15 ...................................... 0 0 0 0 N.A. N.A. N.A. 4 1515–20 ...................................... 0 0 0 0 N.A. N.A. N.A. 1 520–25 ...................................... 0 0 0 0 N.A. N.A. N.A. 0 0>25 .......................................... 0 0 0 0 N.A. N.A. N.A. 0 0


2–5 .......................................... 1 0 0 0 0 0 1 11 05–10 ........................................ 9 0 0 0 0 0 4 2 010–15 ...................................... 1 0 0 0 0 0 1 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 49 0 5 73 69 68 13 41 05–10 ........................................ 34 0 5 12 10 3 0 0 010–15 ...................................... 1 0 1 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 1 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 5 10 0 0 0 0 0 0 25–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 1020–25 ...................................... 0 0 0 0 0 0 0 0 1>25 .......................................... 0 0 0 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 0



15–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 210–15 ...................................... 0 0 0 0 0 0 0 0 815–20 ...................................... 0 0 0 0 0 0 0 0 520–25 ...................................... 0 0 0 0 0 0 0 0 1>25 .......................................... 0 0 0 0 0 0 0 0 11


2–5 .......................................... 0 0 0 0 0 0 8 144 15–10 ........................................ 0 0 0 0 0 0 0 45 110–15 ...................................... 0 0 0 0 0 0 0 1 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 72 N.A. N.A. 28 N.A. 77 16 103 05–10 ........................................ 82 N.A. N.A. 70 N.A. 84 19 47 010–15 ...................................... 37 N.A. N.A. 115 N.A. 14 1 4 015–20 ...................................... 4 N.A. N.A. 30 N.A. 3 0 0 020–25 ...................................... 2 N.A. N.A. 6 N.A. 0 0 0 0>25 .......................................... 7 N.A. N.A. 3 N.A. 0 0 0 0


2–5 .......................................... 12 23 0 0 0 0 0 0 15–10 ........................................ 7 19 0 0 0 0 0 0 310–15 ...................................... 0 0 0 0 0 0 0 0 115–20 ...................................... 0 0 0 0 0 0 0 0 220–25 ...................................... 0 0 0 0 0 0 0 0 1>25 .......................................... 0 0 0 0 0 0 0 0 1



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 9 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 2 N.A. N.A. N.A. N.A. N.A. 0 14 05–10 ........................................ 0 N.A. N.A. N.A. N.A. N.A. 0 24 010–15 ...................................... 0 N.A. N.A. N.A. N.A. N.A. 0 33 0



15–20 ...................................... 0 N.A. N.A. N.A. N.A. N.A. 0 32 020–25 ...................................... 0 N.A. N.A. N.A. N.A. N.A. 0 10 0>25 .......................................... 0 N.A. N.A. N.A. N.A. N.A. 38 82 0


2–5 .......................................... 10 6 0 0 0 0 0 0 05–10 ........................................ 2 6 0 0 0 0 0 0 010–15 ...................................... 19 30 0 0 0 0 0 0 015–20 ...................................... 9 10 0 0 0 0 0 0 020–25 ...................................... 1 0 0 0 0 0 0 0 0>25 .......................................... 1 0 0 0 0 0 0 0 0



2–5 .......................................... 2 0 0 0 0 0 0 0 05–10 ........................................ 9 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 N.A. 0 N.A. N.A. 18 3 N.A. 55–10 ........................................ 0 N.A. 0 N.A. N.A. 16 5 N.A. 010–15 ...................................... 0 N.A. 0 N.A. N.A. 6 0 N.A. 015–20 ...................................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 020–25 ...................................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 0> 25 ........................................ 0 N.A. 0 N.A. N.A. 0 0 N.A. 0


2–5 .......................................... N.A. 0 12 19 0 0 0 0 05–10 ........................................ N.A. 0 0 12 0 0 0 0 010–15 ...................................... N.A. 0 5 5 0 0 0 0 015–20 ...................................... N.A. 0 3 2 0 0 0 0 020–25 ...................................... N.A. 0 5 0 0 0 0 0 0> 25 ........................................ N.A. 0 0 0 0 0 0 0 0


2–5 .......................................... 16 0 2 45 9 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 70 0 0 7 4 15–10 ........................................ 0 0 ................ 151 0 0 16 2 110–15 ...................................... 0 0 ................ 60 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0> 25 ........................................ 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 N.A. 1 N.A. N.A. N.A.



5–10 ........................................ 0 0 0 0 N.A. 1 N.A. N.A. N.A.10–15 ...................................... 0 0 0 0 N.A. 6 N.A. N.A. N.A.15–20 ...................................... 0 0 0 0 N.A. 1 N.A. N.A. N.A.20–25 ...................................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.> 25 ........................................ 0 0 0 0 N.A. 0 N.A. N.A. N.A.


2–5 .......................................... N.A. 0 1 1 0 1 1 N.A. 05–10 ........................................ N.A. 0 0 0 0 0 1 N.A. 110–15 ...................................... N.A. 0 0 0 0 0 3 N.A. 015–20 ...................................... N.A. 0 0 0 0 0 1 N.A. 020–25 ...................................... N.A. 0 0 0 0 0 0 N.A. 0> 25 ........................................ N.A. 0 0 0 0 0 7 N.A. 0


2–5 .......................................... 9 4 15 85 76 4 14 24 05–10 ........................................ 93 9 13 61 21 12 3 0 010–15 ...................................... 37 0 10 3 4 0 0 0 015–20 ...................................... 9 0 0 0 0 0 0 0 020–25 ...................................... 1 0 1 0 0 0 0 0 0> 25 ........................................ 1 0 9 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 0 0 0 23 2 135–10 ........................................ 0 0 ................ 0 0 0 0 2 010–15 ...................................... 0 0 ................ 6 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0> 25 ........................................ 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 5 3 N.A.5–10 ........................................ 0 0 0 0 0 0 0 0 N.A.10–15 ...................................... 0 0 0 0 0 0 0 0 N.A.15–20 ...................................... 0 0 0 0 0 0 0 0 N.A.20–25 ...................................... 0 0 0 0 0 0 0 0 N.A.> 25 ........................................ 0 0 0 0 0 0 0 0 N.A.


2–5 .......................................... 5 0 0 0 0 04 N.A. N.A. N.A.5–10 ........................................ 1 0 0 0 0 01 N.A. N.A. N.A.10–15 ...................................... 0 0 0 0 0 0 N.A. N.A. N.A.15–20 ...................................... 0 0 0 0 0 0 N.A. N.A. N.A.20–25 ...................................... 0 0 0 0 0 0 N.A. N.A. N.A.> 25 ........................................ 0 0 0 0 0 0 N.A. N.A. N.A.


2–5 .......................................... N.A. N.A. 16 39 77 54 8 32 05–10 ........................................ N.A. N.A. 27 56 75 34 4 13 010–15 ...................................... N.A. N.A. 20 32 19 9 5 5 015–20 ...................................... N.A. N.A. 17 18 10 2 0 0 020–25 ...................................... N.A. N.A. 6 14 0 0 0 0 0> 25 ........................................ N.A. N.A. 13 52 0 0 0 0 0


2–5 .......................................... 3 3 0 0 0 0 0 0



5–10 ........................................ 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0



2–5 .......................................... 2 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 2 0 3 4 0 3 19 55–10 ........................................ 0 0 0 0 1 0 0 1 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 28 0 40 N.A. 0 N.A. N.A. 13 05–10 ........................................ 6 0 23 N.A. 0 N.A. N.A. 18 010–15 ...................................... 1 0 5 N.A. 0 N.A. N.A. 45 015–20 ...................................... 1 0 8 N.A. 0 N.A. N.A. 47 020–25 ...................................... 0 0 2 N.A. 0 N.A. N.A. 7 0> 25 ........................................ 0 0 3 N.A. 0 N.A. N.A. 0 0


2–5 .......................................... 3 0 13 0 0 0 0 0 05–10 ........................................ 6 1 0 0 0 0 0 0 010–15 ...................................... 23 1 0 0 0 0 0 0 015–20 ...................................... 4 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 19 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0



2–5 .......................................... N.A. 27 0 0 0 0 0 0 05–10 ........................................ N.A. 0 0 0 0 0 0 0 010–15 ...................................... N.A. 0 0 0 0 0 0 0 015–20 ...................................... N.A. 0 0 0 0 0 0 0 020–25 ...................................... N.A. 0 0 0 0 0 0 0 0> 25 ........................................ N.A. 1 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 2 5 0 5 22 55–10 ........................................ 0 2 0 2 4 1 3 24 010–15 ...................................... 0 0 0 0 5 0 0 6 015–20 ...................................... 0 0 0 0 0 0 0 6 020–25 ...................................... 0 0 0 0 0 0 0 4 0> 25 ........................................ 0 0 0 0 0 0 0 19 0




2–5 .......................................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 44 05–10 ........................................ N.A. N.A. N.A. N.A. 0 N.A. N.A. 32 010–15 ...................................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 015–20 ...................................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 020–25 ...................................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 0> 25 ........................................ N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 0


2–5 .......................................... 28 2 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 5 0 0 12 2 15–10 ........................................ 0 0 ................ 17 0 0 11 0 010–15 ...................................... 0 0 ................ 2 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0> 25 ........................................ 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 N.A. 0 0 0 0 0 0 05–10 ........................................ 0 N.A. 0 0 0 0 0 0 010–15 ...................................... 0 N.A. 0 0 0 0 0 0 015–20 ...................................... 0 N.A. 0 0 0 0 0 0 020–25 ...................................... 0 N.A. 0 0 0 0 0 0 0> 25 ........................................ 0 N.A. 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 N.A. N.A. N.A. N.A. 1 0 0 05–10 ........................................ 0 N.A. N.A. N.A. N.A. 0 0 0 010–15 ...................................... 0 N.A. N.A. N.A. N.A. 0 0 0 015–20 ...................................... 0 N.A. N.A. N.A. N.A. 0 0 0 020–25 ...................................... 0 N.A. N.A. N.A. N.A. 0 0 0 0> 25 ........................................ 0 N.A. N.A. N.A. N.A. 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 0 0 0 0 0 05–10 ........................................ 0 0 ................ 0 0 0 0 0 010–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0> 25 ........................................ 0 0 ................ 0 0 0 0 0 0





2–5 .......................................... N.A. N.A. N.A. N.A. 0 0 0 0 05–10 ........................................ N.A. N.A. N.A. N.A. 0 0 0 0 010–15 ...................................... N.A. N.A. N.A. N.A. 0 0 0 0 015–20 ...................................... N.A. N.A. N.A. N.A. 0 0 0 0 020–25 ...................................... N.A. N.A. N.A. N.A. 0 0 0 0 0> 25 ........................................ N.A. N.A. N.A. N.A. 0 0 0 0 0


2–5 .......................................... 0 0 0 1 0 11 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 7 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 38 0 0 0 0 05–10 ........................................ 0 0 ................ 0 0 0 0 0 010–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0> 25 ........................................ 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.5–10 ........................................ 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.10–15 ...................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.15–20 ...................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.20–25 ...................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.> 25 ........................................ 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.


2–5 .......................................... N.A. N.A. N.A. 8 2 18 0 0 05–10 ........................................ N.A. N.A. N.A. 0 0 19 0 0 010–15 ...................................... N.A. N.A. N.A. 0 0 0 0 0 015–20 ...................................... N.A. N.A. N.A. 0 0 0 0 0 020–25 ...................................... N.A. N.A. N.A. 0 0 0 0 0 0> 25 ........................................ N.A. N.A. N.A. 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0



> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0> 25 ........................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 207 0 0 0 0 05–10 ........................................ 0 0 ................ 56 0 0 0 0 010–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0

1. N.A. (Not Applicable) indicates that all or major portions of these States are part of the subregion and thus, are not considered as being‘‘downwind’’.

2. Codes for the Great Lakes are: LM-Lake Michigan; LS-Lake Superior; LH-Lake Huron; LE-Lake Erie; LC-Lake St. Clair; LO-Lake Ontario.

TABLE II–12.—NUMBER OF IMPACTS IN EACH ‘‘DOWNWIND’’ STATE,1 BY IMPACT CONCENTRATION RANGE FOR EACHSUBREGION—APPROACH 3: 8-HR ‘‘VIOLATING COUNTIES’’



2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. N.A. 0 N.A. N.A. N.A. 9 25 3 55–10 ............................................ N.A. 0 N.A. N.A. N.A. 16 5 0 010–15 .......................................... N.A. 0 N.A. N.A. N.A. 1 0 0 015–20 .......................................... N.A. 0 N.A. N.A. N.A. 6 0 0 020–25 .......................................... N.A. 0 N.A. N.A. N.A. 5 0 0 0>25 .............................................. N.A. 0 N.A. N.A. N.A. 1 0 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 1 0 14 1 22 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0 0 0



2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0



>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 N.A. N.A. N.A. 13 75–10 ............................................ 0 0 0 0 N.A. N.A. N.A. 2 310–15 .......................................... 0 0 0 0 N.A. N.A. N.A. 0 015–20 .......................................... 0 0 0 0 N.A. N.A. N.A. 0 020–25 .......................................... 0 0 0 0 N.A. N.A. N.A. 0 0>25 .............................................. 0 0 0 0 N.A. N.A. N.A. 0 0


2–5 .............................................. 1 0 0 0 0 0 10 9 15–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 36 9 42 45 25 19 1 5 0 8 85–10 ............................................ 2 0 26 0 4 0 0 0 0 0 010–15 .......................................... 0 0 6 0 4 0 0 0 0 0 015–20 .......................................... 0 0 2 0 0 0 0 0 0 0 020–25 .......................................... 0 0 5 0 0 0 0 0 0 0 0>25 .............................................. 0 0 1 0 0 0 0 0 0 0 0



2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 7 0 05–10 ............................................ 0 0 0 0 0 0 0 6 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 00 26 05–10 ............................................ 0 0 0 0 0 0 0 7 110–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 28 N.A. N.A. 22 N.A. 31 8 44 0 12 285–10 ............................................ 32 N.A. N.A. 35 N.A. 38 1 25 0 1 010–15 .......................................... 7 N.A. N.A. 35 N.A. 3 0 0 0 0 015–20 .......................................... 0 N.A. N.A. 11 N.A. 0 0 0 0 0 020–25 .......................................... 0 N.A. N.A. 0 N.A. 0 0 0 0 0 0>25 .............................................. 0 N.A. N.A. 0 N.A. 0 0 0 0 0 0



2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 0



15–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 N.A. N.A. N.A. N.A. N.A. 0 0 0 2 05–10 ............................................ 0 N.A. N.A. N.A. N.A. N.A. 0 11 0 6 2010–15 .......................................... 0 N.A. N.A. N.A. N.A. N.A. 0 16 0 6 615–20 .......................................... 0 N.A. N.A. N.A. N.A. N.A. 1 17 0 0 420–25 .......................................... 0 N.A. N.A. N.A. N.A. N.A. 0 11 0 0 0>25 .............................................. 0 N.A. N.A. N.A. N.A. N.A. 8 17 0 0 0



2–5 .............................................. 2 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 N.A. 0 N.A. N.A. 21 57 N.A. 95–10 ............................................ 0 N.A. 0 N.A. N.A. 64 68 N.A. 310–15 .......................................... 0 N.A. 0 N.A. N.A. 2 10 N.A. 015–20 .......................................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 020–25 .......................................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 0>25 .............................................. 0 N.A. 0 N.A. N.A. 0 0 N.A. 0


2–5 .............................................. N.A. 0 2 3 0 0 1 6 05–10 ............................................ N.A. 0 4 1 0 0 0 0 010–15 .......................................... N.A. 0 0 0 0 0 0 0 015–20 .......................................... N.A. 0 0 0 0 0 0 0 020–25 .......................................... N.A. 0 0 0 0 0 0 0 0>25 .............................................. N.A. 0 0 0 0 0 0 0 0


2–5 .............................................. 2 2 71 1 4 0 0 0 0 0 05–10 ............................................ 0 0 10 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0 0 0



2–5 .............................................. 0 0 0 0 0 0 0 0 0



5–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 7 N.A. 23 N.A. N.A. N.A.5–10 ............................................ 0 0 0 4 N.A. 20 N.A. N.A. N.A.10–15 .......................................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.15–20 .......................................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.20–25 .......................................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.>25 .............................................. 0 0 0 0 N.A. 0 N.A. N.A. N.A.


2–5 .............................................. N.A. 0 0 1 0 9 44 N.A. 05–10 ............................................ N.A. 0 0 0 0 4 29 N.A. 010–15 .......................................... N.A. 0 0 0 0 0 4 N.A. 015–20 .......................................... N.A. 0 0 0 0 0 0 N.A. 020–25 .......................................... N.A. 0 0 0 0 0 1 N.A. 0>25 .............................................. N.A. 0 0 0 0 0 1 N.A. 0


2–5 .............................................. 42 19 72 44 15 44 1 22 0 0 05–10 ............................................ 14 14 53 18 3 2 0 0 0 0 010–15 .......................................... 0 2 40 0 0 0 0 0 0 0 015–20 .......................................... 0 0 10 0 0 0 0 0 0 0 020–25 .......................................... 0 0 7 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0 0 0



2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 6 0 N.A.5–10 ............................................ 0 0 0 0 0 0 1 0 N.A.10–15 .......................................... 0 0 0 0 0 0 0 0 N.A.15–20 .......................................... 0 0 0 0 0 0 0 0 N.A.20–25 .......................................... 0 0 0 0 0 0 0 0 N.A.>25 .............................................. 0 0 0 0 0 0 0 0 N.A.


2–5 .............................................. 0 0 0 0 0 1 N.A. N.A. N.A.5–10 ............................................ 0 0 0 0 0 0 N.A. N.A. N.A.10–15 .......................................... 0 0 0 0 0 0 N.A. N.A. N.A.15–20 .......................................... 0 0 0 0 0 0 N.A. N.A. N.A.20–25 .......................................... 0 0 0 0 0 0 N.A. N.A. N.A.>25 .............................................. 0 0 0 0 0 0 N.A. N.A. N.A.


2–5 .............................................. N.A. N.A. 57 14 39 36 4 18 0 0 35–10 ............................................ N.A. N.A. 66 45 16 16 3 7 0 0 010–15 .......................................... N.A. N.A. 30 17 4 1 0 0 0 0 015–20 .......................................... N.A. N.A. 4 11 0 0 0 0 0 0 020–25 .......................................... N.A. N.A. 0 8 0 0 0 0 0 0 0>25 .............................................. N.A. N.A. 0 8 0 0 0 0 0 0 0





2–5 .............................................. 1 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 10 0 1 7 15–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 28 0 12 N.A. 0 N.A. N.A. 10 05–10 ............................................ 1 0 6 N.A. 0 N.A. N.A. 12 010–15 .......................................... 1 0 1 N.A. 0 N.A. N.A. 6 015–20 .......................................... 0 0 0 N.A. 0 N.A. N.A. 1 020–25 .......................................... 0 0 0 N.A. 0 N.A. N.A. 0 0>25 .............................................. 0 0 0 N.A. 0 N.A. N.A. 0 0


2–5 .............................................. 0 0 13 6 10 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0 0 0



2–5 .............................................. N.A. 2 5 1 0 0 0 0 05–10 ............................................ N.A. 0 0 0 0 0 0 0 010–15 .......................................... N.A. 0 0 0 0 0 0 0 015–20 .......................................... N.A. 0 0 0 0 0 0 0 020–25 .......................................... N.A. 0 0 0 0 0 0 0 0>25 .............................................. N.A. 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 10 18 52 31 23 55–10 ............................................ 0 2 0 9 11 0 2 40 010–15 .......................................... 0 0 0 0 3 0 0 24 015–20 .......................................... 0 0 0 0 0 0 0 2 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. N.A. N.A. N.A. N.A. 0 N.A. N.A. 14 05–10 ............................................ N.A. N.A. N.A. N.A. 0 N.A. N.A. 5 010–15 .......................................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 015–20 .......................................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 020–25 .......................................... N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 0>25 .............................................. N.A. N.A. N.A. N.A. 0 N.A. N.A. 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0 0 0



>25 .............................................. 0 0 0 0 0 0 0 0 0 0 0



2–5 .............................................. 0 N.A. 14 0 0 0 0 0 05–10 ............................................ 0 N.A. 4 0 0 0 0 0 010–15 .......................................... 0 N.A. 0 0 0 0 0 0 015–20 .......................................... 0 N.A. 0 0 0 0 0 0 020–25 .......................................... 0 N.A. 0 0 0 0 0 0 0>25 .............................................. 0 N.A. 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 N.A. N.A. N.A. N.A. 1 0 0 05–10 ............................................ 0 N.A. N.A. N.A. N.A. 0 0 0 010–15 .......................................... 0 N.A. N.A. N.A. N.A. 0 0 0 015–20 .......................................... 0 N.A. N.A. N.A. N.A. 0 0 0 020–25 .......................................... 0 N.A. N.A. N.A. N.A. 0 0 0 0>25 .............................................. 0 N.A. N.A. N.A. N.A. 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0 0 0



2–5 .............................................. N.A. N.A. N.A. N.A. 0 0 0 0 05–10 ............................................ N.A. N.A. N.A. N.A. 0 0 0 0 010–15 .......................................... N.A. N.A. N.A. N.A. 0 0 0 0 015–20 .......................................... N.A. N.A. N.A. N.A. 0 0 0 0 020–25 .......................................... N.A. N.A. N.A. N.A. 0 0 0 0 0>25 .............................................. N.A. N.A. N.A. N.A. 0 0 0 0 0


2–5 .............................................. 0 1 0 9 2 2 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 2 0 5 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 0 0 0



15–20 .......................................... 0 0 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0 0 0



2–5 .............................................. 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.5–10 ............................................ 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.10–15 .......................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.15–20 .......................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.20–25 .......................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.>25 .............................................. 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.


2–5 .............................................. N.A. N.A. N.A. 14 7 52 0 0 05–10 ............................................ N.A. N.A. N.A. 0 0 0 0 0 010–15 .......................................... N.A. N.A. N.A. 0 0 0 0 0 015–20 .......................................... N.A. N.A. N.A. 0 0 0 0 0 020–25 .......................................... N.A. N.A. N.A. 0 0 0 0 0 0>25 .............................................. N.A. N.A. N.A. 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0


2–5 .............................................. 0 0 0 0 0 0 0 0 0 0 05–10 ............................................ 0 0 0 0 0 0 0 0 0 0 010–15 .......................................... 0 0 0 0 0 0 0 0 0 0 015–20 .......................................... 0 0 0 0 0 0 0 0 0 0 020–25 .......................................... 0 0 0 0 0 0 0 0 0 0 0>25 .............................................. 0 0 0 0 0 0 0 0 0 0 0


TABLE II–13.—NUMBER OF IMPACTS IN EACH ‘‘DOWNWIND’’ STATE 1,2 BY IMPACT CONCENTRATION RANGE FOR EACHSUBREGION—APPROACH 4: 8–HR ‘‘ALL GRID CELLS’’



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... N.A. 0 N.A. N.A. N.A. 10 64 5 395–10 ........................................ N.A. 0 N.A. N.A. N.A. 20 8 0 010–15 ...................................... N.A. 0 N.A. N.A. N.A. 5 0 0 015–20 ...................................... N.A. 0 N.A. N.A. N.A. 11 0 0 020–25 ...................................... N.A. 0 N.A. N.A. N.A. 10 0 0 0>25 .......................................... N.A. 0 N.A. N.A. N.A. 1 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 1 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 0


TABLE II–13.—NUMBER OF IMPACTS IN EACH ‘‘DOWNWIND’’ STATE 1,2 BY IMPACT CONCENTRATION RANGE FOR EACHSUBREGION—APPROACH 4: 8–HR ‘‘ALL GRID CELLS’’—Continued

15–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 1 0 20 3 36 0 1 0 05–10 ........................................ 0 0 0 01 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–2 ........................................ 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 0 0 24 65 0 645–10 ........................................ 0 0 ................ 0 0 13 25 3 410–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 1 0 0 0 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 N.A. N.A. N.A. 18 695–10 ........................................ 0 0 0 0 N.A. N.A. N.A. 2 3910–15 ...................................... 0 0 0 0 N.A. N.A. N.A. 0 015–20 ...................................... 0 0 0 0 N.A. N.A. N.A. 0 020–25 ...................................... 0 0 0 0 N.A. N.A. N.A. 0 0>25 .......................................... 0 0 0 0 N.A. N.A. N.A. 0 0


2–5 .......................................... 2 0 0 0 0 0 11 20 15–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 56 11 89 70 34 20 1 9 05–10 ........................................ 2 0 46 2 10 0 0 0 010–15 ...................................... 0 0 7 0 8 0 0 0 015–20 ...................................... 0 0 3 0 3 0 0 0 020–25 ...................................... 0 0 5 0 1 0 0 0 0>25 .......................................... 0 0 1 0 0 0 0 0 0


2–5 .......................................... 9 12 ................ 1 0 0 0 0 205–10 ........................................ 0 0 ................ 0 0 0 0 0 3210–15 ...................................... 0 0 ................ 0 0 0 1 0 1715–20 ...................................... 0 0 ................ 0 0 0 10 0 120–25 ...................................... 0 0 ................ 0 0 0 13 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 0



5–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 10 0 255–10 ........................................ 0 0 0 0 0 0 6 0 1910–15 ...................................... 0 0 0 0 0 0 0 0 715–20 ...................................... 0 0 0 0 0 0 0 0 120–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 76 05–10 ........................................ 0 0 0 0 0 0 0 32 110–15 ...................................... 0 0 0 0 0 0 0 4 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 82 N.A. N.A. 83 N.A. 34 16 96 05–10 ........................................ 44 N.A. N.A. 51 N.A. 40 1 30 010–15 ...................................... 13 N.A. N.A. 41 N.A. 4 0 0 015–20 ...................................... 1 N.A. N.A. 12 N.A. 0 0 0 020–25 ...................................... 0 N.A. N.A. 0 N.A. 0 0 0 0>25 .......................................... 0 N.A. N.A. 0 N.A. 0 0 0 0


2–5 .......................................... 21 84 ................ 0 0 0 0 0 45–10 ........................................ 4 8 ................ 0 0 0 0 0 610–15 ...................................... 0 0 ................ 0 0 0 0 0 1515–20 ...................................... 0 0 ................ 0 0 0 0 0 3520–25 ...................................... 0 0 ................ 0 0 0 0 0 8>25 .......................................... 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 025 ............................................ 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–2 ........................................ 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 N.A. N.A. N.A. N.A. N.A. 0 0 0



5–10 ........................................ 0 N.A. N.A. N.A. N.A. N.A. 0 42 010–15 ...................................... 0 N.A. N.A. N.A. N.A. N.A. 0 38 015–20 ...................................... 0 N.A. N.A. N.A. N.A. N.A. 1 22 020–25 ...................................... 0 N.A. N.A. N.A. N.A. N.A. 4 15 0>25 .......................................... 0 N.A. N.A. N.A. N.A. N.A. 12 17 0


2–5 .......................................... 3 0 ................ 0 0 0 0 0 05–10 ........................................ 10 32 ................ 0 0 0 0 0 010–15 ...................................... 11 42 ................ 0 0 0 0 0 015–20 ...................................... 2 21 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 3 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 N.A. 0 N.A. N.A. 26 122 N.A. 1015–10 ........................................ 0 N.A. 0 N.A. N.A. 89 132 N.A. 2210–15 ...................................... 0 N.A. 0 N.A. N.A. 7 16 N.A. 015–20 ...................................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 020–25 ...................................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 0>25 .......................................... 0 N.A. 0 N.A. N.A. 0 0 N.A. 0


2–5 .......................................... N.A. 1 8 9 0 0 2 19 05–10 ........................................ N.A. 0 8 2 0 0 0 0 010–15 ...................................... N.A. 0 0 0 0 0 0 0 015–20 ...................................... N.A. 0 0 0 0 0 0 0 020–25 ...................................... N.A. 0 0 0 0 0 0 0 0>25 .......................................... N.A. 0 0 0 0 0 0 0 0


2–5 .......................................... 20 3 163 4 12 0 0 0 05–10 ........................................ 5 0 24 0 1 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 75 0 32 63 0 545–10 ........................................ 0 0 ................ 86 0 9 31 3 010–15 ...................................... 0 0 ................ 17 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0




2–5 .......................................... 0 0 0 7 N.A. 31 N.A. N.A. N.A.5–10 ........................................ 0 0 0 4 N.A. 31 N.A. N.A. N.A.10–15 ...................................... 0 0 0 0 N.A. 1 N.A. N.A. N.A.15–20 ...................................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.20–25 ...................................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.>25 .......................................... 0 0 0 0 N.A. 0 N.A. N.A. N.A.


2–5 .......................................... N.A. 0 0 1 0 20 70 N.A. 05–10 ........................................ N.A. 0 0 0 0 9 47 N.A. 010–15 ...................................... N.A. 0 0 0 0 0 8 N.A. 015–20 ...................................... N.A. 0 0 0 0 0 0 N.A. 020–25 ...................................... N.A. 0 0 0 0 0 1 N.A. 0>25 .......................................... N.A. 0 0 0 0 0 1 N.A. 0


2–5 .......................................... 95 39 92 77 21 47 1 22 05–10 ........................................ 46 15 104 20 3 2 0 0 010–15 ...................................... 15 2 94 0 0 0 0 0 015–20 ...................................... 6 0 23 0 0 0 0 0 020–25 ...................................... 0 0 13 0 0 0 0 0 0>25 .......................................... 0 0 1 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 52 0 27 51 0 405–10 ........................................ 0 0 ................ 84 0 12 12 0 110–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 0 0 0 0 0 05–1 .......................................... 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 9 0 N.A.5–10 ........................................ 0 0 0 0 0 0 1 0 N.A.10–15 ...................................... 0 0 0 0 0 0 0 0 N.A.15–20 ...................................... 0 0 0 0 0 0 0 0 N.A.20–25 ...................................... 0 0 0 0 0 0 0 0 N.A.>25 .......................................... 0 0 0 0 0 0 0 0 N.A.


2–5 .......................................... 0 0 0 0 0 2 N.A. N.A. N.A.5–10 ........................................ 0 0 0 0 0 0 N.A. N.A. N.A.10–15 ...................................... 0 0 0 0 0 0 N.A. N.A. N.A.15–20 ...................................... 0 0 0 0 0 0 N.A. N.A. N.A.20–25 ...................................... 0 0 0 0 0 0 N.A. N.A. N.A.>25 .......................................... 0 0 0 0 0 0 N.A. N.A. N.A.


2–5 .......................................... N.A. N.A. 117 18 44 37 7 39 05–10 ........................................ N.A. N.A. 120 59 20 17 4 12 010–15 ...................................... N.A. N.A. 35 32 18 2 0 0 015–20 ...................................... N.A. N.A. 4 31 0 0 0 0 020–25 ...................................... N.A. N.A. 0 12 0 0 0 0 0>25 .......................................... N.A. N.A. 0 35 0 0 0 0 0




2–5 .......................................... 5 37 ................ 0 0 0 0 0 05–10 ........................................ 0 0 ................ 0 0 0 0 0 010–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0


Impacts (ppb) AR LA TX OK KS NE SD ND MN

2–5 .......................................... 1 0 0 0 0 0 0 0 05–1 .......................................... 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 15 0 1 24 15–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 53 0 46 N.A. 0 N.A. N.A. 27 05–10 ........................................ 9 0 27 N.A. 0 N.A. N.A. 79 010–15 ...................................... 1 0 2 N.A. 0 N.A. N.A. 38 015–20 ...................................... 0 0 0 N.A. 0 N.A. N.A. 21 020–25 ...................................... 0 0 0 N.A. 0 N.A. N.A. 6 0>25 .......................................... 0 0 0 N.A. 0 N.A. N.A. 0 0


2–5 .......................................... 31 8 32 26 0 0 0 0 05–10 ........................................ 18 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 0 0 0 0 0 05–10 ........................................ 0 0 ................ 0 0 0 0 0 010–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... N.A. 0 3 5 0 0 0 0 05–10 ........................................ N.A. 0 0 0 0 0 0 0 010–15 ...................................... N.A. 0 0 0 0 0 0 0 015–20 ...................................... N.A. 0 0 0 0 0 0 0 020–25 ...................................... N.A. 0 0 0 0 0 0 0 0>25 .......................................... N.A. 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 10 22 70 67 73 265–10 ........................................ 0 2 0 21 38 0 2 116 010–15 ...................................... 0 0 0 1 9 0 0 57 015–20 ...................................... 0 0 0 0 0 0 0 8 020–25 ...................................... 0 0 0 0 0 0 0 2 0



>25 .......................................... 0 0 0 0 0 0 0 2 0


2–5 .......................................... N.A. N.A. N.A. N.A. N.A. N.A. N.A. 47 05–10 ........................................ N.A. N.A. N.A. N.A. N.A. N.A. N.A. 18 010–15 ...................................... N.A. N.A. N.A. N.A. N.A. N.A. N.A. 0 015–20 ...................................... N.A. N.A. N.A. N.A. N.A. N.A. N.A. 0 020–25 ...................................... N.A. N.A. N.A. N.A. N.A. N.A. N.A. 0 0>25 .......................................... N.A. N.A. N.A. N.A. N.A. N.A. N.A. 0 0


2–5 .......................................... 6 0 9 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 1 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 59 0 0 6 3 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 1 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0



2–5 .......................................... 0 N.A. 3 14 0 0 0 0 05–10 ........................................ 0 N.A. 14 4 0 0 0 0 010–15 ...................................... 0 N.A. 4 0 0 0 0 0 015–20 ...................................... 0 N.A. 0 0 0 0 0 0 020–25 ...................................... 0 N.A. 0 0 0 0 0 0 0>25 .......................................... 0 N.A. 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 1 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 4 N.A. N.A. N.A. N.A. 6 0 0 05–10 ........................................ 0 N.A. N.A. N.A. N.A. 0 0 0 010–15 ...................................... 0 N.A. N.A. N.A. N.A. 0 0 0 015–20 ...................................... 0 N.A. N.A. N.A. N.A. 0 0 0 020–25 ...................................... 0 N.A. N.A. N.A. N.A. 0 0 0 0>25 .......................................... 0 N.A. N.A. N.A. N.A. 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 1 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 1 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0



>25 .......................................... 0 0 0 0 0 0 0 0 0



2–5 .......................................... N.A. N.A. N.A. N.A. 0 0 0 0 05–10 ........................................ N.A. N.A. N.A. N.A. 0 0 0 0 010–15 ...................................... N.A. N.A. N.A. N.A. 0 0 0 0 015–20 ...................................... N.A. N.A. N.A. N.A. 0 0 0 0 020–25 ...................................... N.A. N.A. N.A. N.A. 0 0 0 0 0>25 .......................................... N.A. N.A. N.A. N.A. 0 0 0 0 0


2–5 .......................................... 0 1 0 15 2 2 0 6 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 6 0 5 0 0 0 0 0 05–10 ........................................ 0 2 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0≤ 25 ......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 0 0 0 0 0 05–10 ........................................ 0 0 ................ 0 0 0 0 0 010–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0



2–5 .......................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.5–10 ........................................ 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.10–15 ...................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.15–20 ...................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.20–25 ...................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.>25 .......................................... 0 0 0 N.A. N.A. N.A. N.A. N.A. N.A.


2–5 .......................................... N.A. N.A. N.A. 17 7 74 0 6 05–10 ........................................ N.A. N.A. N.A. 0 0 0 0 0 010–15 ...................................... N.A. N.A. N.A. 0 0 0 0 0 015–20 ...................................... N.A. N.A. N.A. 0 0 0 0 0 020–25 ...................................... N.A. N.A. N.A. 0 0 0 0 0 0>25 .......................................... N.A. N.A. N.A. 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 0 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 0



15–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 0 0 1 0 0 0 05–10 ........................................ 0 0 0 0 0 0 0 0 010–15 ...................................... 0 0 0 0 0 0 0 0 015–20 ...................................... 0 0 0 0 0 0 0 0 020–25 ...................................... 0 0 0 0 0 0 0 0 0>25 .......................................... 0 0 0 0 0 0 0 0 0


2–5 .......................................... 0 0 ................ 125 0 0 6 0 05–10 ........................................ 0 0 ................ 0 0 0 0 0 010–15 ...................................... 0 0 ................ 0 0 0 0 0 015–20 ...................................... 0 0 ................ 0 0 0 0 0 020–25 ...................................... 0 0 ................ 0 0 0 0 0 0>25 .......................................... 0 0 ................ 0 0 0 0 0 0


2 Codes for the Great Lakes are: LM—Lake Michigan; LS—Lake Superior; LH—Lake Huron; LE—Lake Erie; LC—Lake St Clair; LO—Lake On-tario.

TABLE II–14a.—PERCENT OF 2007 STATE TOTAL NOX EMISSIONS BY SUBREGION

Percent of State Emissions in Each Subregion

SUBR–1

SUBR–2

SUBR–3

SUBR–4

SUBR–5

SUBR–6

SUBR–7

SUBR–8

SUBR–9

SUBR–10

SUBR–11

SUBR–12 OTHER

TX ....................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00 ............ ............OH ...................... ............ 33.30 ............ ............ ............ 66.70 ............ ............ ............ ............ ............ ............ ............PA ...................... ............ 0.30 79.05 20.61 ............ 0.04 ............ ............ ............ ............ ............ ............ ............IL ........................ 49.45 ............ ............ ............ 50.53 ............ ............ ............ ............ ............ ............ 0.02 ............FL ....................... ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00 ............ ............ ............LA ....................... ............ ............ ............ ............ ............ ............ ............ ............ ............ 40.99 59.01 ............ ............MI ....................... 8.68 83.32 ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 8.00IN ........................ 28.70 7.03 ............ ............ 41.68 22.59 ............ ............ ............ ............ ............ ............ ............TN ...................... ............ ............ ............ ............ 16.71 10.09 ............ 0.63 72.58 ............ ............ ............ ............GA ...................... ............ ............ ............ ............ ............ ............ ............ 6.47 74.19 19.34 ............ ............ ............NY ...................... ............ ............ 31.09 49.56 ............ ............ ............ ............ ............ ............ ............ ............ 19.35KY ...................... ............ ............ ............ ............ 39.00 61.00 ............ ............ ............ ............ ............ ............ ............AL ....................... ............ ............ ............ ............ ............ ............ ............ ............ 73.40 26.60 ............ ............ ............NC ...................... ............ ............ ............ ............ ............ 0.74 13.14 78.04 8.08 ............ ............ ............ ............VA ...................... ............ ............ ............ ............ ............ 7.72 92.20 ............ ............ ............ ............ ............ 0.08WV ..................... ............ ............ 3.70 ............ ............ 74.64 21.66 ............ ............ ............ ............ ............ ............NJ ....................... ............ ............ 0.81 98.98 ............ ............ 0.21 ............ ............ ............ ............ ............ ............MO ..................... ............ ............ ............ ............ 43.60 ............ ............ ............ 0.61 ............ ............ 55.78 ............OK ...................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 86.99 13.01 ............KS ...................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00 ............SC ...................... ............ ............ ............ ............ ............ ............ ............ 93.12 6.44 0.43 ............ ............ ............MS ...................... ............ ............ ............ ............ ............ ............ ............ ............ 49.69 45.56 4.75 ............ ............WI ....................... 87.53 ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 6.02 6.45MD ...................... ............ ............ 3.11 0.48 ............ ............ 96.12 ............ ............ ............ ............ ............ 0.29MN ...................... 0.30 ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 99.70 ............IA ........................ 22.97 ............ ............ ............ 2.73 ............ ............ ............ ............ ............ ............ 74.30 ............MA ...................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00AR ...................... ............ ............ ............ ............ 0.40 ............ ............ ............ 10.54 ............ 85.36 3.71 ............NE ...................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00 ............CT ...................... ............ ............ ............ 96.60 ............ ............ ............ ............ ............ ............ ............ ............ 3.40ME ...................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00NH ...................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00DE ...................... ............ ............ 33.57 23.69 ............ ............ 42.74 ............ ............ ............ ............ ............ ............SD ...................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00 ............RI ........................ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00VT ....................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00ND ...................... ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ 100.00 ............DC ...................... ............ ............ ............ ............ ............ ............ 100.00 ............ ............ ............ ............ ............ ............


1 The emission reductions avoided are assessedassuming a slightly different regional NOX strategythan the strategy analyzed in this notice. However,the results here are nonetheless illustrative of thepotential savings associated with a similar regionalNOX strategy.

2 To inflate cost estimates, use CPI inflator: 1990to 1995=1.17; 1990 to 1996=1.20

TABLE II–14b.—PERCENT 2007 BASE-LINE NOX Emissions by Subregion,by State

Subregion/StatePercent ofsubregiontotal NOX

1:Illinois .................................... 39.50Indiana ................................... 19.49Iowa ....................................... 5.63Michigan ................................ 6.39Minnesota .............................. 0.07Wisconsin .............................. 28.90

Percent of Domain Total ... 6.212:

Indiana ................................... 4.69Michigan ................................ 60.19Ohio ....................................... 27.60Pennsylvania ......................... 0.23Canada .................................. 7.29


Delaware ............................... 2.27Maryland ................................ 0.92New Jersey ........................... 0.34New York ............................... 18.62Pennsylvania ......................... 66.51West Virginia ......................... 1.69Canada .................................. 9.63


Connecticut ........................... 12.15Delaware ............................... 1.55Maryland ................................ 0.14New Jersey ........................... 40.56New York ............................... 28.79Pennsylvania ......................... 16.81


Arkansas ............................... 0.08Illinois .................................... 34.35Indiana ................................... 24.09Iowa ....................................... 0.57Kentucky ................................ 17.42Missouri ................................. 14.04Tennessee ............................. 9.45


Illinois .................................... 0.00Indiana ................................... 10.45Kentucky ................................ 21.80North Carolina ....................... 0.25Ohio ....................................... 38.39Pennsylvania ......................... 0.02Tennessee ............................. 4.57

TABLE II–14b.—PERCENT 2007 BASE-LINE NOX Emissions by Subregion,by State—Continued


Virginia .................................. 2.39West Virginia ......................... 22.12


Delaware ............................... 3.06District of Col ......................... 2.01Maryland ................................ 30.20New Jersey ........................... 0.09North Carolina ....................... 7.34Pennsylvania ......................... 0.00Virginia .................................. 46.78West Virginia ......................... 10.50


Georgia .................................. 5.05North Carolina ....................... 51.88Pennsylvania ......................... 0.00South Carolina ...................... 42.52Tennessee ............................. 0.55


Alabama ................................ 24.11Arkansas ............................... 1.55Georgia .................................. 28.23Louisiana ............................... 0.00Mississippi ............................. 10.71Missouri ................................. 0.15North Carolina ....................... 2.62South Carolina ...................... 1.44Tennessee ............................. 31.20


Alabama ................................ 8.90Florida ................................... 50.02Georgia .................................. 7.50Louisiana ............................... 19.91Mississippi ............................. 10.00South Carolina ...................... 0.10Off Shore ............................... 3.57


Arkansas ............................... 7.96Louisiana ............................... 17.88Mississippi ............................. 0.65Oklahoma .............................. 13.09Texas ..................................... 57.47Off Shore ............................... 2.95


Arkansas ............................... 0.67

TABLE II–14b.—PERCENT 2007 BASE-LINE NOX Emissions by Subregion,by State—Continued


Illinois .................................... 0.02Iowa ....................................... 14.52Kansas .................................. 27.99Minnesota .............................. 19.95Missouri ................................. 16.82Nebraska ............................... 9.96North Dakota ......................... 1.47Oklahoma .............................. 3.79South Dakota ........................ 3.22Wisconsin .............................. 1.58

Percent of Domain Total ... 17.80

Table II–15.—Estimate of Local Control CostAvoided by OTAG Strategy 1, 2

23–Jurisdictions VOC Emission ReductionsAvoided: 513,000 (tpy)

Low-end Local VOC Removal Cost per ton:$2,400 (Average cost of local VOCmeasures selected in RIA)

High-end Local VOC Removal Cost per ton:$10,000 (Integrated Implementation Planlimit)

23–Jurisdictions NOX Emission ReductionsAvoided: 767,000 (tpy)

Low-end Local NOX Removal Cost per ton:$2,200 (Average cost of local VOCmeasures selected in RIA)

High-end Local NOX Removal Cost per ton:$10,000 (Integrated Implementation Planlimit)

23—Jurisdiction Local VOC Removal CostAvoided (million 1990$): Low-end $1,231;High-end $5,131

23—Jurisdiction Local NOX Removal CostAvoided (million 1990$): Low-end $1,687;High-end $7,671

23—Jurisdiction Total Removal Cost Avoided(million 1990$): Low-end $2,918; High-end$12,802

BILLING CODE 6560–50–M


Appendix D—Figures for Section II.

Weight of Evidence Determination of Significant Contribution

Figure II–1. OTAG Modeling Domain.


Figure II–2.—Location of Subregions.


Figure II–3.—OTAG Round 3 Geographic Zones (shaded areas are 3 ‘‘major’’ nonattainment areas).


Figure II–4.—Transport Wind Vectors During Regionally High Ozone Days.

BILLING CODE 6560–50–C


Appendix E—Control Strategies Containedin Model Run 5 of the Ozone TransportAssessment Group

UtilityMandated CAA controls

• Acid Rain Controls (Phase 1 & 2 for allboiler types)

• RACT & NSR in nonattainment areas(NAAs) without waivers

Additional controls

• OTC NOX MOU (Phase II)• 85 percent reduction from 1990 rate or

rate-base of 0.15 lb/mmbtu for all units,whichever is less stringent

Non-Utility Point SourcesMandated CAA controls

• RACT at major sources in NAAs withoutwaivers

• 250 Ton PSD and NSPS (not modeled)• NSR in NAAs without waivers (not

modeled)• CTG & Non-CTG RACT at major sources in

NAAs & throughout OTC• New Source LAER & Offsets for NAAs (not

modeled)• ‘‘9 percent by 99’’ ROP Measures (VOC or

NOX) for serious and above areas

Additional controls

• NOX Controls based on cost per ton ofreduction (< $1,000 per ton)—primarilyLNB technology

Nonroad MobileMandated CAA controls

• Federal Phase II Small Engine Standards• Federal Marine Engine Standards• Federal HDV (>=50 hp) Standards—Phase

1• Federal RFG II (statutory and opt-in areas)• 9.0 RVP maximum elsewhere in OTAG• ‘‘9 percent by 99’’ ROP Measures(VOC or

NOX) for serious and above areas

Additional controls

• Federal Locomotive Standards (includingrebuilds)

• HD Engine 4gm Standard

Highway MobileMandated CAA controls• Tier 1 light-duty and heavy-duty Standards• Federal reformulated gas (RFG II) (statutory

and opt-in areas)• High Enhanced I/M (serious and above

areas)• Low Enhanced I/M for rest of OTR• Basic I/M (mandated areas)

• Clean Fuel Fleets (mandated areas)• 9.0 RVP maximum elsewhere in OTAG• On board vapor recovery

Additional controls

• National LEV• Heavy Duty Vehicle 2 gm Standard• Federal Test Procedure (FTP) revisions• ‘‘9 percent by 99’’ ROP Measures (if

substitute for VOC) in serious and aboveareas

Other Area Source Controls

Mandated CAA controls

• Two Phases of Consumer & CommercialProducts & One Phase of ArchitecturalCoatings

• Stage 1 & 2 Petroleum DistributionControls—NAAs

• Autobody, Degreasing & Dry CleaningControls in NAAs

• ‘‘9 percent by 99’’ ROP Measures (VOC orNOX) (serious and above areas)

[FR Doc. 97–28932 Filed 11–6–97; 8:45 am]

BILLING CODE 6560–50–P–M