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6130 Federal Register / Vol. 62, No. 28 / Tuesday, February 11, 1997 / Rules and Regulationscontained in the IPP must be performedand its implementation documented.2. Adequate documentation must beprovided that enables the reviewer todetermine the emission estimationprocedures and the data sources used todevelop the inventory.3. The point source inventory must becomplete.4. Point source emissions inventorymust have been prepared or calculatedaccording to the current EPA guidance.5. The area source inventory must becomplete.6. The area source emissionsinventory must have been prepared orcalculated according to the current EPAguidance.7. The method (e.g., HighwayPerformance Modeling System or anetwork transportation planning model)used to develop vehicle miles traveled(VMT) estimates must follow EPAguidance. The VMT developmentmethods must be adequately describedand documented in the inventoryreport.8. The MOBILE model must becorrectly used to produce emissionfactors for each of the vehicle classes.9. Non-road mobile emissionsinventory must be prepared according tocurrent EPA guidance for all of thesource categories.B. The EPA is approving this emissioninventory as meeting the requirementsof section 187(a)(1) of the Act. Thereasons why this submittal meets theLevel III criteria are discussed below.Initially, EPA subjected the AlaskaState CO emission inventory to arigorous review. This review pointedout various deficiencies in theinventory. In their updates to theoriginal emissions inventory submittedon August 27, 1992 (Anchorage) andNovember 11, 1992 (Fairbanks), ADECcorrected these deficiencies. Correctionswere made and submitted on December29, 1993 and December 1, 1994. TheDecember 1, 1994 submittal wasprimarily an update to mobile sourcesemission estimates, replacing modelMobile 4.1 with Mobile 5.0a, which isthe EPA approved model consistentwith CAAA requirements andtransporation conformity regulations.1. Inventory Preparation Plan. Alaskasubmitted a final Inventory PreparationPlan (IPP) and accompanying finalQuality Assurance Plan which satisfiedthe EPA’s requirements, and whichwere approved in January 1992.2. Quality assurance. Throughout theemissions inventory, ADEC providesdocumentation of quality assurance. Foreach source category, ADEC identifiesthe methodology employed. WhereADEC methods deviate from EPAsuggested procedures, the rationale forthe alternate method is noted. For eachCO source category, ADEC provides thereference from which it excerptedinformation. When needed, projectionequations are provided to showemission amounts beyond the base year.3. Point Source Inventory. ADEC’spoint source inventory identifiessources whose emissions exceed 10 tonsper year of carbon monoxide. There arefour CO point sources in the Anchoragenonattainment area and nine in theFairbanks nonattainment area. Thedominant industry with CO pointsources for both nonattainment areas iselectric utility power generation. Whilenatural gas is the primary fuel used inAnchorage, it is not available inFairbanks.To compile the point sourceinventory, ADEC reviewed emission andfuel use information available from stateair operating permits, and informationsupplied by permitted facilities throughoperating reports required to besubmitted to ADEC. In addition, ADECcontacted Anchorage and Fairbanks areafuel distributors to identify any sourcesnot already issued an operating permitcapable of emitting more than 10 tonsper year of carbon monoxide. Therewere no such sources.ADEC reports that point sourceemissions for 1990 are 2.35 tons per dayfor Anchorage and 6.06 tons per day forFairbanks.4. Area Source Inventory. ADECsubmitted a complete inventory for COarea sources divided into the followingcategories: natural gas combustion(Anchorage only) fuel oil combustion,coal combustion, propane combustion(Fairbanks only), wood combustion,industrial equipment, solid wasteincineration, and open burning/structural fires. The largest contributorto CO emissions in both nonattainmentareas was wood burning. Emissions foreach source category (except as notedabove) are calculated for the twononattainment areas. The inventoryprovides a discussion per category, anddisplays equations that were used todevelop emissions estimates. Sources ofinformation are provided as needed. Insome cases, ADEC’s methodology differsfrom EPA’s recommended procedures.When this occurs, ADEC notes thereason for the difference. Usually, ADECuses data tailored to the local or statearea rather than using the nationalequations or factors. Area source totalsfor 1990 were 4.96 tons per winter daywithin the Anchorage COnonattainment area, and 12.99 tons perday for the Fairbanks CO nonattainmentarea.5. Vehicle Miles Traveled (VMT). InFairbanks, the Alaska Department ofTransportation and Public Facilities(ADOT&PF) used a combination ofactual 1990 traffic count data and QRS2modeling results for 1990 to provideVMT and travel-weighted speedestimates for each roadway functionalclass. Traffic counts were obtained fromboth the Highway PerformanceMonitoring System (HPMS) andadditional sampling locations operatedby ADOT&PF. ADOT&PF estimatedVMT during an average winter weekdayin Fairbanks to be 1,296,041. InAnchorage, the Municipality usedMinUTP modeling results for 1990 toprovide travel-weighted speed data andVMT for each roadway functional class,generating HPMS-equivalent estimates(based on ADOT&PF guidance). TheMunicipality estimated VMT during anaverage winter weekday in Anchorage tobe 2,854,000.The VMT development methods wereadequately described and documentedin the SIP and satisfy EPA’srequirements. (See 60 FR 33727, June19, 1995.)6. Use of the Mobile Model. TheMobile 4.1 model was used in theoriginal 1992 submittal to EPA, beingthen the most recent emission factormodel, and was retained for the revised1993 submittal for consistency. InDecember 1994, ADEC revised themobile source emission estimates bysubstituting Mobile 5.0a for Mobile 4.1.Today’s approval is based on theDecember 29, 1993 submittal usingMobile 4.1.The model was correctly used toproduce emission factors for each of theeight separate vehicle classes. Inputsspecific to Anchorage and Fairbanksduring the base year were used in themodel: operating mode fractions (cold/hot/stabilized) =65%/0%/35%; VMT formotorcycles =0%; anti-tamperingprogram in place; compliance rate =91%(Anchorage) and 96% (Fairbanks);annual inspection; decentralized I/Mprogram, etc. A default value was usedfor the tampering rate. QualityAssurance is provided within the onroaddiscussion, and methodologiesused to determine each of the inputvariables were presented. On-roadmobile sources are 149.99 tons per dayfor Anchorage and 80.83 tons per dayfor Fairbanks.7. Non-road Inventory. ADECdescribes each category and themethodology employed. When ADEC’smethodology deviates from EPAguidance, it is usually because ADECuses numbers reflective of localscenarios as opposed to nationalaverages. Assumptions, equations, and