IV. Why Is EPA Taking These Actions?

On May 17, 2006, the WVDEP requested redesignation of Huntington to attainment for the 8hour ozone standard. On May 17, 2006, the WVDEP submitted a maintenance plan for Huntington as a SIP revision, to assure continued attainment over the next 12 years, until 2018. Concurrently, West Virginia is requesting that EPA approve the maintenance plan as meeting the requirements of CAA 175A(b) with respect to the 1hour ozone maintenance plan update. EPA is proposing to approve the maintenance plan to fulfill the requirement of section 175A(b) for submission of a maintenance plan update eight years after Huntington was redesignated to attainment of the 1hour ozone NAAQS. EPA believes that such an update must ensure that the maintenance plan in the SIP provides maintenance of the NAAQS for a period of 20 years after an area is initially redesignated to attainment. EPA can propose approval because the maintenance plan, which demonstrates maintenance of the 8hour ozone NAAQS through 2018, also demonstrates maintenance of the 1hour ozone NAAQS through 2018, even though the latter standard is no longer in effect. Huntington was redesignated to attainment of the 1hour ozone NAAQS on December 21, 1994 (59 FR 45985), and, the initial 1hour ozone maintenance plan provided for maintenance through 2005. Ashland was redesignated to attainment of the 1hour ozone NAAQS on June 29, 1995 (60 FR 33748). Section 51.905(e) of the ``Final Rule To Implement the 8Hour RequirementsPhase 1'' April 30, 2004 (69 FR 23999) specifies the conditions that must be satisfied before EPA may approve a modification to a 1hour maintenance plan which: (1) Removes the obligation to submit a maintenance plan for the 1hour ozone NAAQS eight years after approval of the initial 1hour maintenance plan and/ or (2) removes the obligation to implement contingency measures upon a violation of the 1hour NAAQS. EPA believes that section 51.905(e) of the final rule allows a State to make either one or both of these modifications to a 1hour maintenance plan SIP once EPA approves a maintenance plan for the 8hour NAAQS. The maintenance plan will not trigger the contingency plan upon a violation of the 1hour ozone NAAQS, but upon a violation of the 8hour ozone NAAQS. EPA believes that the 8hour standard is now the proper standard which should trigger the contingency plan now that the 1hour NAAQS has been revoked and now that approval of the maintenance plan would allow the State to remove a violation of the 1hour NAAQS obligation from the SIP. EPA has determined that Huntington has attained the standard and has met the requirements for redesignation set forth in section 107(d)(3)(E). V. What Would Be the Effect of These Actions?

Approval of the redesignation request would change the designation of Huntington from nonattainment to attainment for the 8hour ozone NAAQS found at 40 CFR part 81. It would also incorporate into the West Virginia SIP a maintenance plan ensuring continued attainment of the 8 hour ozone NAAQS in Huntington for the next 12 years, until 2018. The maintenance plan includes contingency measures to remedy any future violations of the 8hour NAAQS (should they occur), and identifies the MVEBs for NOX and VOC for transportation conformity purposes for the years 2004, 2009 and 2018. These MVEBs are displayed in the following table:
Table 1.Motor Vehicle Emissions Budgets in Tons per Day (tpd) Year NOX VOC 2004.................................................. 11.5 6.0 2009.................................................. 8.7 4.6 2018.................................................. 4.1 3.0 VI. What Is EPA's Analysis of the State's Request?

EPA is proposing to determine that the HuntingtonAshland area has attained the 8hour ozone standard and that all other redesignation criteria have been met. The following is a description of how the WVDEP's May 17, 2006 submittal satisfies the requirements of section 107(d)(3)(E) of the CAA.
A. The HuntingtonAshland Area Has Attained the 8Hour Ozone NAAQS

EPA is proposing to determine that the HuntingtonAshland area has attained the 8hour ozone NAAQS. For ozone, an area may be considered to be attaining the 8hour ozone NAAQS if there are no violations, as determined in accordance with 40 CFR 50.10 and Appendix I of part 50, based on three complete, consecutive calendar years of qualityassured air quality monitoring data. To attain this standard, the 3year average of the fourthhighest daily
[[Page 39621]]
maximum 8hour average ozone concentrations measured at each monitor, within the area, over each year must not exceed the ozone standard of 0.08 ppm. Based on the rounding convention described in 40 CFR part 50, Appendix I, the standard is attained if the design value is 0.084 ppm or below. The data must be collected and qualityassured in accordance with 40 CFR part 58, and recorded in the Aerometric Information Retrieval System (AIRS). The monitors generally should have remained at the same location for the duration of the monitoring period required for demonstrating attainment.

In the HuntingtonAshland area there is one ozone monitor, located in Cabell County, West Virginia and one ozone monitor in Boyd County, Kentucky that measure air quality with respect to ozone. As part of its redesignation request, West Virginia submitted ozone monitoring data for the years 20022005 for the HuntingtonAshland area. This data has been quality assured and is recorded in AIRS. The fourth high 8hour daily maximum concentrations, along with the threeyear averages, are summarized in Tables 2 and 3.
Table 2.Huntington's Fourth Highest 8Hour Average Values; Cabell Monitor, AIRS ID 540110006
Annual 4th Year high reading (ppm) 2002................................................... 0.097 2003................................................... 0.080 2004................................................... 0.066 2005................................................... 0.082

The average for the 3year period 2002 through 2004 is 0.081 ppm.

The average for the 3year period 2003 through 2005 is 0.076 ppm. Table 3.Ashland's Fourth Highest 8Hour Average Values; Boyd Monitor, AIRS ID 210190017
Annual 4th Year high reading (ppm) 2002................................................... 0.102 2003................................................... 0.088 2004................................................... 0.068 2005................................................... 0.082

The average for the 3year period 2002 through 2004 is 0.086 ppm.

The average for the 3year period 2003 through 2005 is 0.079 ppm.

The air quality data for 20032005 show that the entire Huntington Ashland area has attained the standard with a design value of 0.076 ppm for Huntington and a design value of 0.079 ppm for Ashland. The data collected at the HuntingtonAshland area monitors satisfy the CAA requirement that the 3year average of the annual fourthhighest daily maximum 8hour average ozone concentration is less than or equal to 0.08 ppm. The WVDEP's request for redesignation for Huntington indicates that the data was quality assured in accordance with 40 CFR part 58. The WVDEP uses AIRS as the permanent database to maintain its data and quality assures the data transfers and content for accuracy. In addition, as discussed below with respect to the maintenance plan, WVDEP has committed to continue monitoring in accordance with 40 CFR part 58. In summary, EPA has determined that the data submitted by West Virginia and data taken from AIRS indicates that the HuntingtonAshland area has attained the 8hour ozone NAAQS.
B. The HuntingtonAshland Area Has Met All Applicable Requirements Under Section 110 and Part D of the CAA and Has a Fully Approved SIP Under Section 110(k) of the CAA

EPA has determined that Huntington has met all SIP requirements applicable for purposes of this redesignation under section 110 of the CAA (General SIP Requirements) and that it meets all applicable SIP requirements under Part D of Title I of the CAA, in accordance with section 107(d)(3)(E)(v). In addition, EPA has determined that the SIP is fully approved with respect to all requirements applicable for purposes of redesignation in accordance with section 107(d)(3)(E)(ii). In making these proposed determinations, EPA ascertained what requirements are applicable to the HuntingtonAshland area, and determined that the applicable portions of the SIP meeting these requirements are fully approved under section 110(k) of the CAA. We note that SIPs must be fully approved only with respect to applicable requirements.

The September 4, 1992 Calcagni memorandum (``Procedures for Processing Requests to Redesignate Areas to Attainment,'' Memorandum from John Calcagni, Director, Air Quality Management Division, September 4, 1992) describes EPA's interpretation of section 107(d)(3)(E) with respect to the timing of applicable requirements. Under this interpretation, to qualify for redesignation, States requesting redesignation to attainment must meet only the relevant CAA requirements that came due prior to the submittal of a complete redesignation request. See also Michael Shapiro memorandum, September 17, 1993, and 60 FR 12459, 1246566 (March 7, 1995) (redesignation of DetroitAnn Arbor). Applicable requirements of the CAA that come due subsequent to the area's submittal of a complete redesignation request remain applicable until a redesignation is approved, but are not required as a prerequisite to redesignation. Section 175A(c) of the CAA. Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004). See also 68 FR 25424, 25427 (May 12, 2003) (redesignation of St. Louis).

1. Section 110 General SIP Requirements

Section 110(a)(2) of Title I of the CAA delineates the general requirements for a SIP, which include enforceable emissions limitations and other control measures, means, or techniques, provisions for the establishment and operation of appropriate devices necessary to collect data on ambient air quality, and programs to enforce the limitations. The general SIP elements and requirements set forth in section 110(a)(2) include, but are not limited to, the following:

Section 110(a)(2)(D) requires that SIPs contain certain measures to prevent sources in a State from significantly contributing to air quality problems in another State. To implement this provision, EPA has required certain States to establish programs to address transport of air pollutants in accordance with the NOX SIP Call, October 27, 1998 (63 FR 57356), amendments to the NOX SIP Call, May 14, 1999 (64 FR 26298) and March 2, 2000 (65 FR 11222), and the Clean Air Interstate Rule (CAIR), May 12, 2005 (70 FR 25161). However, the section 110(a)(2)(D) requirements for a State are not linked with a particular nonattainment area's designation and
[[Page 39622]]
classification in that State. EPA believes that the requirements linked with a particular nonattainment area's designation and classifications are the relevant measures to evaluate in reviewing a redesignation request. The transport SIP submittal requirements, where applicable, continue to apply to a State regardless of the designation of any one particular area in the State.

Thus, we do not believe that these requirements should be construed to be applicable requirements for purposes of redesignation. In addition, EPA believes that the other section 110 elements not connected with nonattainment plan submissions and not linked with an area's attainment status are not applicable requirements for purposes of redesignation. West Virginia and Kentucky will still be subject to these requirements after the HuntingtonAshland area is redesignated. The section 110 and Part D requirements, which are linked with a particular area's designation and classification, are the relevant measures to evaluate in reviewing a redesignation request. This policy is consistent with EPA's existing policy on applicability of conformity (i.e., for redesignations) and oxygenated fuels requirement. See Reading, Pennsylvania, proposed and final rulemakings 61 FR 5317453176 (October 10, 1996), 62 FR 24816 (May 7, 1997); ClevelandAkronLorain, Ohio, final rulemaking 61 FR 20458 (May 7, 1996); and Tampa, Florida, final rulemaking 60 FR 62748 (December 7, 1995). See also the discussion on this issue in the Cincinnati redesignation 65 FR 37890 (June 19, 2000), and in the Pittsburgh redesignation 66 FR 50399 (October 19, 2001). Similarly, with respect to the NOX SIP Call rules, EPA noted in its Phase 1 Final Rule to Implement the 8hour Ozone NAAQS, that the NOX SIP Call rules are not ``an `applicable requirement' for purposes of section 110(l) because the NOX rules apply regardless of an area's attainment or nonattainment status for the 8hour (or the 1hour) NAAQS.'' 69 FR 23951, 23983 (April 30, 2004).

EPA believes that section 110 elements not linked to the area's nonattainment status are not applicable for purposes of redesignation. Any section 110 requirements that are linked to the Part D requirements for 8hour ozone nonattainment areas are not yet due, because, as we explain later in this notice, no Part D requirements applicable for purposes of redesignation under the 8hour standard became due prior to submission of the redesignation request.

Because the West Virginia and Kentucky SIPs satisfy all of the applicable general SIP elements and requirements set forth in section 110(a)(2), EPA concludes that West Virginia and Kentucky have satisfied the criterion of section 107(d)(3)(E) regarding section 110 of the Act. 2. Part D Nonattainment Area Requirements Under the 8Hour Standard

The HuntingtonAshland area was designated a basic nonattainment area for the 8hour ozone standard. Sections 172176 of the CAA, found in subpart 1 of Part D, set forth the basic nonattainment requirements for all nonattainment areas. As discussed previously, there are no outstanding Part D submittals under the 1hour standard for this area.

Section 182 of the CAA, found in subpart 2 of Part D, establishes additional specific requirements depending on the area's nonattainment classification. The HuntingtonAshland area was classified as a subpart 1 nonattainment area; therefore, no subpart 2 requirements apply to this area.

With respect to the 8hour standard, EPA proposes to determine that the West Virginia and Kentucky SIPs meet all applicable SIP requirements under Part D of the CAA, because no 8hour ozone standard Part D requirements applicable for purposes of redesignation became due prior to submission of the area's redesignation request. Because the State submitted a complete redesignation request for Huntington prior to the deadline for any submissions required under the 8hour standard, we have determined that the Part D requirements do not apply to Huntington for the purposes of redesignation.

In addition to the fact that Part D requirements applicable for purposes of redesignation did not become due prior to submission of the redesignation request, EPA believes it is reasonable to interpret the general conformity and NSR requirements as not requiring approval prior to redesignation.

With respect to section 176, Conformity Requirements, section 176(c) of the CAA requires States to establish criteria and procedures to ensure that federally supported or funded projects conform to the air quality planning goals in the applicable SIP. The requirement to determine conformity applies to transportation plans, programs, and projects developed, funded or approved under Title 23 U.S.C. and the Federal Transit Act (``transportation conformity'') as well as to all other federally supported or funded projects (``general conformity''). State conformity revisions must be consistent with Federal conformity regulations relating to consultation, enforcement and enforceability that the CAA required the EPA to promulgate.

EPA believes it is reasonable to interpret the conformity SIP requirements as not applying for purposes of evaluating the redesignation request under section 107(d) since State conformity rules are still required after redesignation and Federal conformity rules apply where State rules have not been approved. See Wall v. EPA, 265 F.3d 426, 438440 (6th Cir. 2001), upholding this interpretation. See also 60 FR 62748 (December 7, 1995).

EPA has also determined that areas being redesignated need not comply with the requirement that a NSR program be approved prior to redesignation, provided that the area demonstrates maintenance of the standard without Part D NSR in effect, because PSD requirements will apply after redesignation. The rationale for this view is described in a memorandum from Mary Nichols, Assistant Administrator for Air and Radiation, dated October 14, 1994, entitled, ``Part D NSR Requirements or Areas Requesting Redesignation to Attainment.'' West Virginia has demonstrated that the area will be able to maintain the standard without Part D NSR in effect in Huntington, and therefore, West Virginia need not have a fully approved Part D NSR program prior to approval of the redesignation request. West Virginia's SIPapproved PSD program will become effective in Huntington upon redesignation to attainment. See rulemakings for Detroit, MI (60 FR 1246712468, March 7, 1995); ClevelandAkronLorrain, OH (61 FR 20458, 2046970, May 7, 1996); Louisville, KY (66 FR 53665, October 23, 2001); Grand Rapids, Michigan (61 FR 3183431837, June 21, 1996).
3. Huntington Has a Fully Approved SIP for the Purposes of Redesignation

EPA has fully approved the West Virginia SIP for the purposes of this redesignation. EPA may rely on prior SIP approvals in approving a redesignation request. Calcagni Memo, p. 3; Southwestern Pennsylvania Growth Alliance v. Browner, 144 F. 3d 984, 98990 (6th Cir. 1998), Wall v. EPA, 265 F.3d 426 (6th Cir. 2001), plus any additional measures it may approve in conjunction with a redesignation action. See 68 FR 25425 (May 12, 2003) and citations therein. The HuntingtonAshland area was a 1hour maintenance area at the time of its designation as a basic 8 hour ozone nonattainment area on April 30,
[[Page 39623]]
2004. Because Huntington was a 1hour maintenance area, all previous Part D SIP submittal requirements were fulfilled at the time the area was redesignated to attainment of the 1hour ozone NAAQS or have been fulfilled with the submittal of the 8hour maintenance plan for the area. See rulemakings for Huntington, WV (59 FR 45980 at 4598145982, September 6, 1994); (59 FR 45019, September 6, 1994); and, (59 FR 65719, December 21, 1994). Because there are no outstanding SIP submission requirements applicable for the purposes of redesignation of Huntington, the applicable implementation plan satisfies all pertinent SIP requirements. As indicated previously, EPA believes that the section 110 elements not connected with Part D nonattainment plan submissions and not linked to the area's nonattainment status are not applicable requirements for purposes of redesignation. EPA also believes that no 8hour Part D requirements applicable for purposes of redesignation have yet become due for the HuntingtonAshland area, and therefore they need not be approved into the SIP prior to
redesignation.
4. The Air Quality Improvement in the HuntingtonAshland Area Is Due to Permanent and Enforceable Reductions in Emissions Resulting From Implementation of the SIP and Applicable Federal Air Pollution Control Regulations and Other Permanent and Enforceable Reductions

EPA believes that the States have demonstrated that the observed air quality improvement in the HuntingtonAshland area is due to permanent and enforceable reductions in emissions resulting from implementation of the SIP, Federal measures, and other Stateadopted measures. Emissions reductions attributable to these rules in Huntington are shown in Table 4.
Table 4.Total VOC and NOX Emissions for 2002 and 2004 (tpd) Year Point Area* Nonroad Mobile Total Volatile Organic Compounds (VOC) Year 2002...................................................... 1.1 11.7 4.1 6.8 23.7 Year 2004...................................................... 1.3 12.1 4.3 6.0 23.7 Diff. (0204).................................................. +0.2 +0.4 +0.2 0.8 0 Nitrogen Oxides (NOX) Year 2002...................................................... 12.4 1.2 14.0 11.4 39.0 Year 2004...................................................... 7.4 1.2 17.3 11.5 37.4 Diff. (0204).................................................. 5.0 0 +3.3 +.10 1.6 * Fire emissions are assumed to remain constant.

Between 2002 and 2004, VOC emissions stayed the same, and NOX emissions were reduced by 1.6 tpd, due to the following permanent and enforceable measures implemented or in the process of being implemented in Huntington:
Programs Currently in Effect
(a) National Low Emission Vehicle (NLEV);
(b) Motor vehicle fleet turnover with new vehicles meeting the Tier 2 standards; and,

(c) Clean Diesel Program.

West Virginia has demonstrated that the implementation of permanent enforceable emissions controls have reduced local VOC and
NOX emissions. All of the reductions in VOC are attributable to mobile and nonroad source emission controls such as federally mandated Tier 2 Vehicle and Gasoline Sulfur Program and the Clean Diesel Program.

Nearly all of the reductions in NOX are attributable to the implementation of the NOX SIP Call. West Virginia has indicated in its submittal that the implementation of the
NOX SIP Call, with its mandatory reductions in
NOX emissions from Electric Generating Units (EGUs) and large industrial boilers (nonEGUs), reduced NOX emissions throughout the HuntingtonAshland area. NOX emissions from EGUs in Huntington were reduced by 0.3 tpd between 2002 and 2004. Also, NOX emissions from nonEGU sources in Huntington were reduced by 4.7 tpd between 2002 and 2004. Reductions in NOX emissions from the implementation of the NOX SIP Call from EGUs and nonEGUs in counties adjacent to the Huntington (Cabell and Wayne Counties), such as Boyd (the other county in the Huntington Ashland area) and Lawrence Counties in Kentucky and Putnam County in West Virginia have also occurred. The WVDEP believes that the improvement in ozone air quality from 2002 to 2004 was the result of identifiable, permanent and enforceable reductions in ozone precursor emissions for the same period.

Additionally, WVDEP has identified, but not quantified, additional reductions in VOC emissions that will be achieved as a cobenefit of the reductions in the emission of hazardous air pollutants (HAPs) as a result of implementation of EPA's Maximum Achievable Control Technology (MACT) standards.

Other regulations, such as the nonroad diesel, 69 FR 39858 (June 29, 2004), the heavy duty engine and vehicle standards, 66 FR 5002 (January 18, 2001) and the new Tier 2 tailpipe standards for automobiles, 65 FR 6698 (January 10, 2000), are also expected to greatly reduce emissions throughout the country and thereby reduce emissions impacting the HuntingtonAshland area monitors. The Tier 2 standards came into effect in 2004, and by 2030, EPA expects that the new Tier 2 standards will reduce NOX emissions by about 74 percent nationally. EPA believes that permanent and enforceable emissions reductions are the cause of the longterm improvement in ozone levels and are the cause of the HuntingtonAshland area achieving attainment of the 8hour ozone standard.
5. Huntington Has a Fully Approved Maintenance Plan Pursuant to Section 175A of the CAA

In conjunction with its request to redesignate Huntington to attainment status, West Virginia submitted a SIP revision to provide for maintenance of the 8hour ozone NAAQS in Huntington for at least 12 years after redesignation. West Virginia is requesting that EPA [[Page 39624]]
approve this SIP revision as meeting the requirement of CAA 175A(b) and replace the 1hour ozone maintenance plan update requirement.

Under 40 CFR 51.905(e), the EPA may approve a SIP revision requesting the removal of the obligation to implement contingency measures upon a violation of the 1hour ozone NAAQS when the State submits and EPA approves an attainment demonstration for the 8hour ozone NAAQS for an area initially designated nonattainment for the 8 hour NAAQS or a maintenance SIP for the 8hour NAAQS for an area initially designated attainment for the 8hour NAAQS. The rationale behind 40 CFR 51.905(e) is to ensure that Huntington maintains the applicable ozone standard (the 8hour standard in areas where the 1 hour standard has been revoked). EPA believes this rationale analogously applies to areas that were not initially designated, but are redesignated as attainment with the 8hour ozone NAAQS. Therefore, EPA intends to treat redesignated areas as though they had been initially designated attainment of the 8hour ozone NAAQS, and accordingly proposes to relieve Huntington of its maintenance plan obligations with respect to the 1hour standard. Once approved, the maintenance plan for the 8hour ozone NAAQS will ensure that the SIP for Huntington meets the requirements of the CAA regarding maintenance of the applicable 8hour ozone standard.

What is required in a maintenance plan?

Section 175A of the CAA sets forth the elements of a maintenance plan for areas seeking redesignation from nonattainment to attainment. Under section 175A, the plan must demonstrate continued attainment of the applicable NAAQS for at least 10 years after approval of a redesignation of an area to attainment. Eight years after the redesignation, the State must submit a revised maintenance plan demonstrating that attainment will continue to be maintained for the next 10year period following the initial 10year period (12 years in Huntington's case). To address the possibility of future NAAQS violations, the maintenance plan must contain such contingency measures, with a schedule for implementation, as EPA deems necessary to assure prompt correction of any future 8hour ozone violations. Section 175A of the CAA sets forth the elements of a maintenance plan for areas seeking redesignation from nonattainment to attainment. The Calcagni memorandum dated September 4, 1992, provides additional guidance on the content of a maintenance plan. An ozone maintenance plan should address the following provisions:
(a) An attainment emissions inventory;
(b) A maintenance demonstration;
(c) A monitoring network;
(d) Verification of continued attainment; and
(e) A contingency plan.
Analysis of the Huntington Maintenance Plan
(a) Attainment InventoryAn attainment inventory includes the emissions during the time period associated with the monitoring data showing attainment. An attainment year of 2004 was used for Huntington since it is a reasonable year within the 3year block of 20022004 and accounts for reductions attributable to implementation of the CAA requirements to date.

The WVDEP prepared comprehensive VOC and NOX emissions inventories for Huntington, including point, area, mobile onroad, and mobile nonroad sources for a base year of 2002.

To develop the NOX and VOC base year emissions inventories, WVDEP used the following approaches and sources of data: (i) Point source emissionsWest Virginia maintains its point source emissions inventory data on the iSTEPS database, which is commercial software purchased from a vendor, Pacific Environmental Services. Facilities subject to emissions inventory reporting requirements were those operating point sources subject to Title V permitting requirements. Affected sources were identified from the WVDEP's Regulation 30 database which is maintained by the WVDEP's Title V Permitting Group. For the 2002 inventory, diskettes were populated with iSTEPS software information, as well as sourcespecific data from the previous year and sent to facilities for updates of their 2002 activity and emissions data. The facilities then sent the diskettes back to the State and, where WVDEP staff quality assured the data and submitted it to EPA's Central Data Exchange (CDX) site as well as to contractors for the Visibility Improvement State and Tribal Association of the Southeast (VISTAS), a Regional Planning Organization (RPO).

WVDEP used EPA's Clean Air Markets Division (CAMD) actual data to calculate 2002 summer daily NOX emissions from EGUs. To calculate summer weekday NOX emissions WVDEP used EPA's CAMD data for the date range of June 1, 2002 through August 31, 2002. WVDEP staff filtered the resulting NOX data to select West Virginia sources (Ceredo and Big Sandy peaking stations). The NOX data was downloaded, all weekend days were deleted and the remaining emissions were added together, and the total was divided by 65. Since, CAMD data does not require VOC emissions reporting, WVDEP used VISTAS summer daily VOC emissions values for 2002.
(ii) Area source emissionsIn order to calculate the area source emissions inventory the WVDEP took the annual values from the VISTAS base year inventory and derived the typical ozone summer weekday, using procedures outlined in the EPA's Emissions Modeling Clearinghouse (EMCH) Memorandum, ``Temporal Allocation of Annual Emissions Using EMCH Temporal Profiles, April 29, 2002.'' This enabled WVDEP to arrive at the ``typical'' summer day emissions.
(iii) Onroad mobile source emissionsVISTAS developed 2002 on road mobile (highway) emissions inventory data based on vehicle miles traveled (VMT) updates provided by WVDEP. VISTAS also estimated future emissions based upon expected growth for the future years 2009 and 2018. However, Federal Transportation Conformity requirements dictate that the WVDEP consult with the Metropolitan Planning Organization (MPO) responsible for transportation planning in developing SIP revisions which may establish motor vehicle emissions budgets (MVEB). This applies to the maintenance plan submitted by WVDEP on May 17, 2006. Therefore, the WVDEP has consulted with the Huntington MPO, the KYOVA Interstate Planning Commission (KYOVA). The KYOVA provided base year and projection emissions data consistent with their most recent available Travel Demand Model (TDM) results along with EPA's most recent emission factor model, MOBILE6.2. The WVDEP used these data to estimate highway emissions and, in consultation with the KYOVA, to develop highway emissions budgets for VOC and NOX. The KYOVA must evaluate future Long Range Transportation Plans and Transportation Improvement Programs to ensure that the associated emissions are equal to or less then the final emissions budgets. The budgets are designed to facilitate a positive conformity determination while ensuring overall maintenance of the 8hour NAAQS. It should be noted that the MVEBs and budgets only represent the Huntington, West Virginia (Cabell and Wayne Counties) portion of the nonattainment area.
(iv) Mobile nonroad emissionsThe 2002 mobile nonroad emissions [[Page 39625]]
inventory was developed by WVDEP staff using the NONROAD2005b Model.

The 2004 attainment year VOC and NOX emissions Huntington are summarized along with the 2009 and 2018 projected emissions for Huntington in tables 5 and 6, which covers the demonstration of maintenance for this portion of the area. EPA has concluded that West Virginia has adequately derived and documented the 2004 attainment year VOC and NOX emissions for Huntington. (b) Maintenance DemonstrationOn May 17, 2006, the WVDEP submitted a SIP revision to supplement its May 17, 2006 redesignation request. The submittal by WVDEP consists of the maintenance plan as required by section 175A of the CAA. The Huntington plan shows maintenance of the 8hour ozone NAAQS by demonstrating that current and future emissions of VOC and NOX remain at or below the attainment year 2004 emissions levels throughout Huntington through the year 2018. The Huntington maintenance demonstration need not be based on modeling. See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001); Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004). See also 66 FR 53094, 5309953100 (October 19, 2001), 68 FR 2543032 (May 12, 2003).

Tables 5 and 6 specify the Huntington VOC and NOX emissions for 2004, 2009, and 2018. The WVDEP chose 2009 as an interim year in the 12year maintenance demonstration period to demonstrate that the VOC and NOX emissions are not projected to increase above the 2004 attainment level during the time of the 12year maintenance period.
Table 5.Total VOC Emissions for 20042018 (tpd)
2004 VOC 2009 VOC 2018 VOC Source category emissions emissions emissions Mobile \1\....................... 6.0 4.6 3.0 Nonroad.......................... 4.3 3.9 3.2 Area \2\......................... 12.1 11.2 12.4 Point............................ 1.3 0.9 1.1

Total \3\.................... 23.7 20.6 19.7 \1\ 2004 emissions are actual; Emission budgets are established for 2009 and 2018 and include a reallocation from the safety margin. \2\ Fire emissions are assumed to remain constant.
\3\ Sums may not total exactly due to rounding.
Table 6.Total NOX Emissions 20042018 (tpd)
2004 NOX
Source category emissions 2009 NOX 2018 NOX \1\ emissions emissions Mobile \1\....................... 11.5 8.7 4.1 Nonroad.......................... 17.3 13.4 12.6 Area \2\......................... 1.2 1.3 1.5 Point............................ 7.4 8.1 8.8 ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤

Total \3\.................... 37.4 31.5 27.0 \1\ 2004 emissions are actual; Emission budgets are established for 2009 and 2018 and include a reallocation from the safety margin. \2\ Fire emissions are assumed to remain constant.

\3\ Sums may not total exactly due to rounding.

Additionally, the following mobile programs are either effective or due to become effective and will further contribute to the maintenance demonstration of the 8hour ozone NAAQS:

In addition to the permanent and enforceable measures, CAIR, promulgated May 12, 2005 (70 FR 25161) should have positive impacts on West Virginia and Kentucky's air quality. CAIR, which will be implemented in the eastern portion of the country in two phases (2009 and 2015), should reduce long range transport of ozone precursors, which will have a beneficial effect on air quality in the Huntington Ashland area.

Currently, West Virginia is in the process of adopting rules to address CAIR through State rules 45CSR39, 45CSR40, and 45CSR41, which require annual and ozone season NOX reductions from EGUs and ozone season NOX reductions from nonEGUs. These rules will be submitted to EPA as a SIP revision by September 11, 2006 as required in the May 12, 2005 (70 FR 25161) Federal Register publication.

Based upon the comparison of the projected emissions and the attainment year emissions along with the additional measures, EPA concludes that WVDEP has successfully demonstrated that the 8hour ozone standard should be maintained in Huntington.
(c) Monitoring NetworkThere is currently two monitor measuring ozone in the HuntingtonAshland area, one in Cabell County, West Virginia and one in Boyd County, Kentucky. West Virginia will continue to operate its current air quality monitor (located in Cabell County) in accordance with 40 CFR part 58.
(d) Verification of Continued AttainmentThe State of West Virginia has the legal authority to implement and enforce specified measures necessary to attain and maintain the NAAQS. Additionally, Federal programs such as Tier 2/Low Sulfur Gasoline Rule, 2007 OnRoad Diesel Engine Rule, and Federal Nonroad Engine/Equipment Rules will continue to be implemented on a national level. These programs help provide the reductions necessary for the HuntingtonAshland area to maintain attainment.

In addition to maintaining the key elements of its regulatory program, West Virginia requires ambient and source emissions data to track attainment and maintenance. The WVDEP proposes to fully update its point, area, and mobile emission inventories at 3year intervals [[Page 39626]]
as required by the Consolidated Emissions Reporting Rule (CERR) to assure that its growth projections relative to emissions in these areas are sufficiently accurate to assure ongoing attainment with the NAAQS. The WVDEP will review stationary source VOC and NOX emissions by review of annual emissions statements and by update of its emissions inventories. The area source inventory will be updated using the same techniques as the 2002 ozone inventory. However, some source categories may be updated using historic activity levels determined from Bureau of Economic Analysis (BEA) data or West Virginia University/Regional Research Institute (WVU/RRI) population estimates. The mobile source inventory model will be updated by obtaining county level VMT from the West Virginia Department of Transportation (WVDOT) for the subject year and calculating emissions using the latest approved MOBILE model. Alternatively, the motor vehicle emissions may be obtained in consultation with the Metropolitan Planning Organization (MPO), the KYOVA, using methodology similar to that used for Transportation Conformity purposes. The WVDEP shall also continue to operate the existing ozone monitoring stations in the areas pursuant to 40 CFR 58 throughout the maintenance period and submit qualityassured ozone data to EPA through the AIRS system.
(e) The Maintenance Plan's Contingency MeasuresThe contingency plan provisions are designed to promptly correct a violation of the NAAQS that occurs after redesignation. Section 175A of the Act requires that a maintenance plan include such contingency measures as EPA deems necessary to ensure that the State will promptly correct a violation of the NAAQS that occurs after redesignation. The maintenance plan should identify the events that would ``trigger'' the adoption and implementation of a contingency measure(s), the contingency measure(s) that would be adopted and implemented, and the schedule indicating the time frame by which the State would adopt and implement the measure(s).

The ability of Huntington to stay in compliance with the 8hour ozone standard after redesignation depends upon VOC and NOX emissions in Huntington remaining at or below 2004 levels. The State's maintenance plan projects VOC and NOX emissions to decrease and stay below 2004 levels through the year 2018. The State's maintenance plan lays out two situations where the need to adopt and implement a contingency measure to further reduce emissions would be triggered. Those situations are as follows:
(i) If the triennial inventories indicate emissions growth in excess of 10 percent of the 2002 baseyear inventory or if a monitored air quality exceedance pattern indicates that an ozone NAAQS violation may be imminentThe maintenance plan states that an exceedance pattern would include, but is not limited to, the measurement of three exceedances or more occurring at the same monitor during a calendar year. The plan also states that comprehensive tracking inventories will also be developed every 3 years using current EPAapproved methods to assure that its growth projections relative to emissions in Huntington are sufficiently accurate to assure ongoing attainment with the NAAQS. If the 2002 baseyear inventory or a monitored air quality exceedance pattern occurs, the following measure will be implemented:

The following schedule for adoption, implementation and compliance applies to the contingency measures concerning the option of implementing regulatory requirements.

The following schedule for adoption, implementation and compliance applies to the voluntary contingency measures.

The maintenance plan adequately addresses the five basic components of a maintenance plan: attainment inventory, maintenance demonstration, monitoring network, verification of continued attainment, and a contingency plan. EPA believes that the maintenance plan SIP revision submitted by West Virginia for Huntington meets the requirements of section 175A of the Act.
VII. Are the Motor Vehicle Emissions Budgets Established and Identified in the Huntington Maintenance Plan Adequate and Approvable? A. What Are the Motor Vehicle Emissions Budgets (MVEBs)?

Under the CAA, States are required to submit, at various times, control strategy SIPs and maintenance plans in ozone areas. These control strategy SIPs (i.e., RFP SIPs and attainment demonstration SIPs) and maintenance plans identify and establish MVEBs for certain criteria pollutants and/or their precursors to address pollution from onroad mobile sources. In the maintenance plan the MVEBs are termed ``onroad mobile source emissions budgets.'' Pursuant to 40 CFR part 93 and 51.112, MVEBs must be established in an ozone maintenance plan. An MVEB is the portion of the total allowable emissions that is allocated to highway and transit vehicle use and emissions. An MVEB serves as a ceiling on emissions from an area's planned transportation system. The MVEB concept is further explained in the preamble to the November 24, 1993, transportation conformity rule (58 FR 62188). The preamble also describes how to establish and revise the MVEBs in control strategy SIPs and maintenance plans.

Under section 176(c) of the CAA, new transportation projects, such as the construction of new highways, must ``conform'' to (i.e., be consistent with) the part of the State's air quality plan that addresses pollution from cars and trucks. ``Conformity'' to the SIP means that transportation activities will not cause new air quality violations, worsen existing violations, or delay timely attainment of or reasonable progress towards the national ambient air quality standards. If a transportation plan does not ``conform,'' most new projects that would expand the capacity of roadways cannot go forward. Regulations at 40 CFR part 93 set forth EPA policy, criteria, and procedures for demonstrating and assuring conformity of such transportation activities to an SIP.

When reviewing submitted ``control strategy'' SIPs or maintenance plans containing MVEBs, EPA must affirmatively find the MVEB budget contained therein ``adequate'' for use in determining transportation conformity. After EPA affirmatively finds the submitted MVEB is adequate for transportation conformity purposes, that MVEB can be used by State and Federal agencies in determining whether proposed transportation projects ``conform'' to the state implementation plan as required by section 176(c) of the CAA. EPA's substantive criteria for determining ``adequacy'' of a MVEB are set out in 40 CFR 93.118(e)(4). EPA's process for determining ``adequacy'' consists of three basic steps: Public notification of an SIP submission, a public comment period, and EPA's adequacy finding. This process for determining the adequacy of submitted SIP MVEBs was initially outlined in EPA's May 14, 1999 guidance, ``Conformity Guidance on Implementation of March 2, 1999, Conformity Court Decision.'' This guidance was finalized in the Transportation Conformity Rule Amendments for the ``New 8Hour Ozone and PM2.5 National Ambient Air Quality Standards and Miscellaneous Revisions for Existing Areas; Transportation Conformity Rule AmendmentsResponse to Court Decision and Additional Rule Change'' on July 1, 2004 (69 FR 40004). EPA follows this guidance and rulemaking in making its adequacy determinations.

The MVEBs for Huntington are listed in Table 1 of this document for the 2004, 2009, and 2018 years and are the projected emissions for the onroad mobile sources plus any portion of the safety margin allocated to the MVEBs (safety margin allocation for 2009 and 2018 only). These emission budgets, when approved by EPA, must be used for transportation conformity determinations.

B. What Is a Safety Margin?

A ``safety margin'' is the difference between the attainment level of emissions (from all sources) and the projected level of emissions (from all sources) in the maintenance plan. The attainment level of emissions is the level of emissions during one of the years in which the area met the NAAQS. The following example is for the 2018 safety margin: Huntington first attained the 8hour ozone NAAQS during the 2002 to 2004 time period. The State used 2004 as the year to determine attainment levels of emissions for Huntington. The total emissions from point, area, mobile onroad, and mobile nonroad sources in 2004 equaled 23.7 tpd of VOC and 37.4 tpd of NOX. The WVDEP projected emissions out to the year 2018 and projected a total of 19.7 tpd of VOC and 27.0 tpd of NOX from all sources in Huntington. The safety margin for 2018 would be the difference between these amounts, or 4.0 tpd of VOC and 10.4 tpd of NOX. The emissions up to the level of the attainment year including the safety margins are projected to maintain the area's air quality consistent with the 8hour ozone NAAQS. The safety margin is the extra emissions reduction below the attainment levels that can be allocated for emissions by various sources as long as the total emission levels are maintained at or below the attainment levels. Table 7 shows the safety margins for the 2009 and 2018 years.
Table 7.2009 and 2018 Safety Margins for Huntington VOC NOX Inventory year emissions emissions (tpd) (tpd) 2004 Attainment................................. 23.7 37.4 2009 Interim.................................... 20.6 31.5 2009 Safety Margin.............................. 3.1 5.9 2004 Attainment................................. 23.7 37.4 2018 Final...................................... 19.7 27.0 2018 Safety Margin.............................. 4.0 10.4

The WVDEP allocated 1.1 tpd NOX and 0.6 tpd VOC to the 2009 interim VOC projected onroad mobile source emissions projection and the 2009 interim NOX projected onroad mobile source emissions projection to arrive at the 2009 MVEBs. For the 2018 MVEBs the WVDEP allocated 0.5 tpd NOX and 0.4 tpd VOC from the 2018 safety margins to arrive at the 2018 MVEBs. Once allocated to the mobile source budgets these portions of the safety margins are no longer available, and may no longer be allocated to any other source category. Table 8 shows the final 2009 and 2018 MVEBS for Huntington. [[Page 39628]]
Table 8.2009 and 2018 Final MVEBs for Huntington VOC emissions NOX emissions Inventory year (tpd) (tpd) 2009 projected onroad mobile source 4.0 7.6 projected emissions..................
2009 Safety Margin Allocated to MVEBs. 0.6 1.1 2009 MVEBs............................ 4.6 8.7 2018 projected onroad mobile source 2.6 3.6 projected

FOR FURTHER INFORMATION CONTACT Amy Caprio, (215) 814-2156, or by e- mail at caprio.amy@epa.gov.