E7-7900. Approval and Promulgation of Air Quality Implementation Plans; State of Montana; Missoula Carbon Monoxide Redesignation to Attainment, Designation of Areas for Air Quality Planning Purposes, and Approval of Related Revisions

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

EPA is proposing to approve State Implementation Plan (SIP) revisions submitted by the State of Montana. On May 27, 2005, the Governor of Montana submitted a request to redesignate the Missoula “moderate” carbon monoxide (CO) nonattainment area to attainment for the CO National Ambient Air Quality Standard (NAAQS). The Governor also submitted a CO maintenance plan which includes transportation conformity motor vehicle emission budgets (MVEB) for 2000, 2010, and 2020. In addition, EPA is proposing to approve CO periodic emission inventories for 1993 and 1996 for the Missoula nonattainment area that the State had previously submitted. This action is being taken under section 110 of the Clean Air Act.

DATES:

Comments must be received on or before May 25, 2007.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-R08-OAR-2006-0163, by one of the following methods:

—http://www.regulations.gov. Follow the on-line instructions for submitting comments.

—E-mail: [e-mail] and [e-mail].

—Fax: [phone] (please alert the individual listed in the FOR FURTHER INFORMATION CONTACT if you are faxing comments).

—Mail: Callie A. Videtich, Director, Air and Radiation Program, Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129.

—Hand Delivery: Callie A. Videtich, Director, Air and Radiation Program, Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129. Such deliveries are only accepted Monday through Friday, 8 a.m. to 4:30 p.m., excluding Federal holidays. Special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPA-R08-OAR-2006-0163. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at http://www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA, without going through http://www.regulations.gov your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about EPA's public docket visit the EPA Docket Center homepage at http://www.epa.gov/​epahome/​dockets.htm. For additional instructions on submitting comments, go to Section I. General Information of the SUPPLEMENTARY INFORMATION section of this document.

Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in http://www.regulations.gov or in hard copy at the Air and Radiation Program, Environmental Protection Agency (EPA), Region 8, 1595 Wynkoop Street, Denver, Colorado 80202-1129. EPA requests that if at all possible, you contact the individual listed in the FOR FURTHER INFORMATION CONTACT section to view the hard copy of the docket. You may view the hard copy of the docket Monday through Friday, 8 a.m. to 4 p.m., excluding Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Kerri Fiedler, Environmental Protection Agency, Region 8, 1595 Wynkoop Street, Denver, Colorado 80202-1129, phone [phone], and e-mail at: [e-mail].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information

II. What is the purpose of this action?

III. What is the State's process to submit these materials to EPA?

IV. EPA's Evaluation of the Missoula Redesignation Request and Maintenance Plan

V. EPA's Evaluation of the Transportation Conformity Requirements

VI. Consideration of Section 110(l) of the Clean Air Act

VII. Proposed Action

VIII. Statutory and Executive Order Reviews

Definitions

For the purpose of this document, we are giving meaning to certain words or initials as follows:

(i) The words or initials Act or CAA mean or refer to the Clean Air Act, unless the context indicates otherwise.

(ii) The words EPA, we, us or our mean or refer to the United States Environmental Protection Agency.

(iii) The initials NAAQS mean National Ambient Air Quality Standard.

(iv) The initials SIP mean or refer to State Implementation Plan.

(v) The word State means the State of Montana, unless the context indicates otherwise.

I. General Information

(a). What Should I Consider as I Prepare My Comments for EPA?

1. Submitting CBI. Do not submit this information to EPA through http://www.regulations.gov or e-mail. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as CBI and then identify electronically within the disk or CD-ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

(b). Tips for Preparing Your Comments. When submitting comments, remember to:

A. Identify the rulemaking by docket number and other identifying information (subject heading, Federal Register date and page number).

B. Follow directions—The agency may ask you to respond to specific questions or organize comments by referencing a Code of Federal Regulations (CFR) part or section number.

C. Explain why you agree or disagree; suggest alternatives and substitute language for your requested changes.

D. Describe any assumptions and provide any technical information and/or data that you used.

E. If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced.

F. Provide specific examples to illustrate your concerns, and suggest alternatives.

G. Explain your views as clearly as possible, avoiding the use of profanity or personal threats.

Make sure to submit your comments by the comment period deadline identified.

II. What is the purpose of this action?

In this action, we are proposing approval of a change in the legal designation of the Missoula area from nonattainment for CO to attainment. We're proposing approval of the year 2000 attainment emission inventory and the maintenance plan that is designed to keep the area in attainment for CO for the next 13 years. We're also proposing approval of the transportation conformity motor vehicle emission budgets (MVEB) for 2000, 2010, and 2020, and we're proposing approval of the 1993 and 1996 CO periodic emission inventories.

We originally designated Missoula as nonattainment for CO under the provisions of the 1977 CAA Amendments (see 43 FR 8962, March 3, 1978). On November 15, 1990, the Clean Air Act Amendments of 1990 were enacted (Pub. L. 101-549, 104 Stat. 2399, codified at 42 U.S.C. 7401-7671q). Under section 107(d)(1)(C) of the Clean Air Act (CAA), we designated the Missoula area as nonattainment for CO because the area had been designated as nonattainment before November 15, 1990. Under section 186 of the CAA, Missoula was classified as a “moderate” CO nonattainment area with a design value less than or equal to 12.7 parts per million (ppm), and was required to attain the CO NAAQS by December 31, 1995. See 56 FR 56694, November 6, 1991. Further information regarding this classification and the accompanying requirements are described in the “General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990.” See 57 FR 13498, April 16, 1992.

Under the CAA, we can change designations if acceptable data are available and if certain other requirements are met. See CAA section 107(d)(3)(D). Section 107(d)(3)(E) of the CAA provides that the Administrator may not promulgate a redesignation of a nonattainment area to attainment unless:

(i) The Administrator determines that the area has attained the national ambient air quality standard;

(ii) The Administrator has fully approved the applicable implementation plan for the area under CAA section 110(k);

(iii) The Administrator determines that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the applicable implementation plan and applicable Federal air pollutant control regulations and other permanent and enforceable reductions;

(iv) The Administrator has fully approved a maintenance plan for the area as meeting the requirements of CAA section 175A; and,

(v) The State containing such area has met all requirements applicable to the area under section 110 and part D of the CAA.

Before we can approve the redesignation request, we must decide that all applicable SIP elements have been fully approved. Approval of the applicable SIP elements may occur simultaneously with our final approval of the redesignation request. That's why we are also proposing approval of the 1993 and 1996 CO periodic emission inventories and the year 2000 emission inventory.

III. What is the State's process to submit these materials to EPA?

Section 110(k) of the CAA addresses our actions on submissions of revisions to a SIP. The CAA requires States to observe certain procedural requirements in developing SIP revisions for submittal to us. Section 110(a)(2) of the CAA requires that each SIP revision be adopted after reasonable notice and public hearing. This must occur prior to the revision being submitted by a State to us.

The Missoula City-County Air Pollution Control Board (MCCAPCB) held a public hearing for the Missoula CO redesignation request and the maintenance plan on November 18, 2004. The MCCAPCB adopted the Missoula CO redesignation request and maintenance plan on March 7, 2005. The Missoula CO redesignation request and maintenance plan were then forwarded to the Montana Department of Environmental Quality (MDEQ) for the State to conduct its public hearing. The MDEQ held a public hearing for the Missoula CO redesignation request and the maintenance plan on April 22, 2005 after which the SIP materials were forwarded to the Governor for his submittal to EPA. These SIP revision materials were submitted by the Governor to us on May 27, 2005.

We have evaluated the Governor's submittal and have concluded that the State met the requirements for reasonable notice and public hearing under section 110(a)(2) of the CAA. By operation of law, under section 110(k)(1)(B) of the CAA, the Governor's May 27, 2005, submittal became complete on November 27, 2005.

IV. EPA's Evaluation of the Missoula Redesignation Request and Maintenance Plan

Under the CAA, we can change designations of areas if acceptable data are available and if certain other requirements are met. See CAA section 107(d)(3)(D). We have reviewed the Missoula area's redesignation request and maintenance plan (section 2.0) and believe that approval of the request is warranted, consistent with the requirements of CAA section 107(d)(3)(E) as presented in our section II above.

As we noted above, before we can approve the redesignation request, we must decide that all applicable SIP elements have been fully approved. Approval of the applicable SIP elements may occur simultaneously with final approval of the redesignation request. That's why we are also proposing to approve the 1993 and 1996 periodic emission inventories and the year 2000 attainment inventory (to also suffice as the 1999 periodic emission inventory.) The following are descriptions of how the section 107(d)(3)(E) requirements are being addressed.

(a) Redesignation Criterion: The Area Must Have Attained the Carbon Monoxide (CO) NAAQS

Section 107(d)(3)(E)(i) of the CAA states that for an area to be redesignated to attainment, the Administrator must determine that the area has attained the applicable NAAQS. As described in 40 CFR 50.8, the national primary ambient air quality standards for carbon monoxide are 9 parts per million (10 milligrams per cubic meter) for an 8-hour average concentration not to be exceeded more than once per year, and 35 parts per million (40 milligrams per cubic meter) for a 1-hour average concentration not to be exceeded more than once per year. 40 CFR 50.8 continues by stating that the levels of CO in the ambient air shall be measured by a reference method based on 40 CFR part 50, Appendix C, and designated in accordance with 40 CFR part 53 or an equivalent method designated in accordance with 40 CFR part 53.

Attainment of the CO standards is not a momentary phenomenon based on short-term data. Instead, we consider an area to be in attainment if each of the CO ambient air quality monitors in the area doesn't have more than one exceedance of the relevant CO standard over a one-year period. See 40 CFR 50.8 and 40 CFR 50, Appendix C. If any monitor in the area's CO monitoring network records more than one exceedance of the relevant CO standard during a one-year calendar period, then the area is in violation of the CO NAAQS. In addition, our interpretation of the CAA and EPA national policy ^[1] has been that an area seeking redesignation to attainment must show attainment of the CO NAAQS for at least a continuous two-year calendar period. In addition, the area must also continue to show attainment through the date that we promulgate the redesignation in the Federal Register.

Montana's CO redesignation request for the Missoula area is based on an analysis of quality assured ambient air quality monitoring data that are relevant to the redesignation request. As presented in section 2.1.1 of the maintenance plan, ambient air quality monitoring data for consecutive calendar years 2000 through 2003 show a measured exceedance rate of the CO NAAQS of 1.0 or less per year, per monitor, in the Missoula nonattainment area. Further, we have reviewed ambient air quality data from 2004 through December 2006 and the Missoula area continues to show attainment of the CO NAAQS. All of these data were collected and analyzed as required by EPA (see 40 CFR 50.8 and 40 CFR 50, Appendix C) and have been archived by the State in our Air Quality System (AQS) national database. Therefore, we believe the Missoula area has met the first component for redesignation: demonstration of attainment of the CO NAAQS. We note that the State has also committed, in the maintenance plan, to continue the necessary operation of the CO monitor in compliance with all applicable Federal regulations and guidelines.

(b) Redesignation Criterion: The Area Must Have Met All Applicable Requirements Under Section 110 and Part D of the CAA and Title II of the CAA

To be redesignated to attainment, section 107(d)(3)(E)(v) requires that an area must meet all applicable requirements under section 110 and part D of the CAA. We interpret section 107(d)(3)(E)(v) to mean that for a redesignation to be approved by us, the State must meet all requirements that applied to the subject area prior to or at the time of the submission of a complete redesignation request. In our evaluation of a redesignation request, we don't need to consider other requirements of the CAA that became due after the date of the submission of a complete redesignation request.

1. CAA Section 110 Requirements

On January 10, 1980, we approved revisions to Montana's SIP as meeting the requirements of section 110(a)(2) of the CAA (see 45 FR 2034). Although section 110 of the CAA was amended in 1990, most of the changes were not substantial. Thus, we have determined that the SIP revisions approved in 1980 continue to satisfy the requirements of section 110(a)(2). In addition, we have analyzed the SIP elements we are approving as part of this action, and we have determined they comply with the relevant requirements of section 110(a)(2).

2. Part D Requirements

Before the Missoula “moderate” CO nonattainment area may be redesignated to attainment, the State must have fulfilled the applicable requirements of part D. Under part D, an area's classification indicates the requirements to which it will be subject. Subpart 1 of part D sets forth the basic nonattainment requirements applicable to all nonattainment areas, whether classified or nonclassifiable. Subpart 3 of part D contains specific provisions for “moderate” CO nonattainment areas.

The relevant subpart 1 requirements are contained in sections 172(c) and 176. Our General Preamble (see 57 FR 13529, 13533, April 16, 1992) provides EPA's interpretations of the CAA requirements for “moderate” CO areas. The General Preamble (see 57 FR 13530, et seq.) provides that the applicable requirements of CAA section 172 are 172(c)(3) (emissions inventory), 172(c)(5) (new source review permitting program), 172(c)(7) (the section 110(a)(2) air quality monitoring requirements), and 172(c)(9) (contingency measures). It is also worth noting that we interpreted the requirements of sections 172(c)(2) (reasonable further progress—RFP) and 172(c)(6) (other measures) as being irrelevant to a redesignation request because they only have meaning for an area that is not attaining the standard. See EPA's September 4, 1992, memorandum entitled, “Procedures for Processing Requests to Redesignate Areas to Attainment”, and the General Preamble, 57 FR at 13564, dated April 16, 1992. Finally, the State has not sought to exercise the options that would trigger sections 172(c)(4) (identification of certain emissions increases) and 172(c)(8) (equivalent techniques). Thus, these provisions are also not relevant to this redesignation request.

The relevant subpart 3 provisions were created when the CAA was amended on November 15, 1990 and appear in section 187 of the CAA. The new CAA requirements for a CO nonattainment area, classified as “moderate” with a design value of 12.7 ppm or less, that are applicable to Missoula are a 1990 base year inventory (CAA section 187(a)(1)), contingency provisions (CAA section 187(a)(3)), and periodic emission inventories (CAA section 187(a)(5)).

A. Relevant CAA subpart 1 requirements.

1. Emissions Inventory. For the CAA section 172(c)(3) emissions inventory requirement, the State submitted a 1990 base year CO emissions inventory for the Missoula area on July 18, 1995 which met the requirements of section 172(c)(3) of the CAA. We approved this inventory on December 15, 1997 (62 FR 65613).

2. New Source Review (NSR) and Prevention of Significant Deterioration (PSD). For the CAA section 172(c)(5) New Source Review (NSR) requirements, the CAA requires all nonattainment areas to meet several requirements regarding NSR, including provisions to ensure that increased emissions will not result from any new or modified stationary major sources and a general offset rule. The State of Montana has a fully-approved NSR program (60 FR 36715, July 18, 1995.) The State also has a fully approved PSD program (60 FR 36715, July 18, 1995) that will apply, instead of nonattainment NSR, if we approve the redesignation to attainment.

3. Air Quality Monitoring Requirements. For the CAA section 172(c)(7) provisions (compliance with the CAA section 110(a)(2) Air Quality Monitoring Requirements), our interpretations are presented in the General Preamble (57 FR 13535). CO nonattainment areas are to meet the “applicable” air quality monitoring requirements of section 110(a)(2) of the CAA. We have determined that the Missoula area has met the applicable air quality monitoring requirements of section 110(a)(2) of the CAA. See our descriptions in section IV.A above.

4. Contingency Measures. Section 172(c)(9) of the CAA requires the submittal of contingency measures to be implemented in the event that an area fails to make reasonable further progress or to attain the NAAQS by the date applicable (which for a CO nonattainment area, with a design value of less than 12.7 ppm, was December 31, 1995.) To meet this requirement the State submitted a contingency measure, involving residential woodburning devices, on March 2, 1994. We approved this CO contingency measure on December 13, 1994 (59 FR 64133).

5. Conformity. Section 176 of the CAA contains requirements related to conformity. Although EPA's regulations (see 40 CFR 51.390) require that states adopt transportation conformity provisions in their SIPs for areas designated nonattainment or subject to an EPA-approved maintenance plan, we have decided that a transportation conformity SIP is not an applicable requirement for purposes of evaluating a redesignation request under section 107(d) of the CAA. This decision is reflected in EPA's 1996 approval of the Boston carbon monoxide redesignation. (See 61 FR 2918, January 30, 1996.)

B. Relevant CAA subpart 3 requirements.

1. Emissions Inventory. For the CAA section 187(a)(1) emissions inventory requirement, the State submitted a 1990 base year CO emissions inventory for the Missoula area on July 18, 1995 which met the requirements of section 187(a)(1) of the CAA. We approved this inventory on December 15, 1997 (62 FR 65613).

2. Periodic emission inventories. For the CAA section 187(a)(5) periodic emissions inventory requirement, the State submitted CO periodic emission inventories (PEI) for 1993 and 1996 on January 27, 2000. In addition, the State submitted a year 2000 CO emission inventory, on July 19, 2004, that qualifies for the 1999 PEI and is also the basis for the attainment year 2000 CO emission inventory that is part of the State's Missoula CO maintenance plan. We have reviewed these CO periodic emission inventories and have determined they contain comprehensive information with respect to point, area, non-road, and on-road mobile sources and were prepared in accordance with EPA guidance. We are proposing approval of the 1993 PEI, the 1996 PEI, and the year 2000 attainment inventory (for the 1999 PEI requirement) in conjunction with this action's proposed approval of the Missoula CO redesignation to attainment and maintenance plan.

3. CAA Title II requirements. The relevant CAA Title II requirement is contained in section 211(m)(1) which requires the implementation of an oxygenated fuels program for CO areas with a design value of 9.5 ppm or greater.

A. Title II, Part A of the CAA: Oxygenated fuels program (CAA section 211(m)(1)).

Section 211(m)(1) of the CAA requires the submittal of a SIP revision to implement an oxygenated fuels program for CO nonattainment areas with a design value of 9.5 ppm or greater. To address this requirement, the State submitted a SIP revision on November 6, 1992 for the implementation of an oxygenated fuels program in Missoula County. EPA approved this SIP revision on November 8, 1994 (see 59 FR 55585).

(c) Redesignation Criterion: The Area Must Have a Fully Approved SIP Under Section 110(k) of the CAA

Section 107(d)(3)(E)(ii) of the CAA states that for an area to be redesignated to attainment, it must be determined that the Administrator has fully approved the applicable implementation plan for the area under section 110(k).

As noted above, EPA previously approved SIP revisions based on the pre-1990 CAA as well as SIP revisions required under the 1990 amendments to the CAA. In this action, EPA is proposing approval of the Missoula area's 1993 periodic CO emissions inventory, the 1996 periodic CO emissions inventory, and the 2000 CO emission inventory (as meeting the 1999 periodic emissions inventory requirement). Thus, with our final approval of these SIP revisions, we will have fully approved the Missoula area's CO element of the SIP under section 110(k) of the CAA.

(d) Redesignation Criterion: The Area Must Show That the Improvement in Air Quality Is Due to Permanent and Enforceable Emissions Reductions

Section 107(d)(3)(E)(iii) of the CAA provides that for an area to be redesignated to attainment, the Administrator must determine that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the applicable implementation plan, implementation of applicable Federal air pollutant control regulations, and other permanent and enforceable reductions.

The CO emissions reductions for the Missoula area, that are further described in section 2.3 of the maintenance plan, were achieved primarily through an oxygenated fuels program, Federal Motor Vehicle Control Program, residential woodburning regulations, changes in the transportation infrastructure involving the reconstruction of the Brooks/South/Russell (B/S/R) intersection, and outdoor open burning regulations. These five control strategies are fully discussed in section 2.3 of the maintenance plan and are summarized below.

1. Oxygenated Fuels. As described in section 2.3.2.1 of the maintenance plan, since November of 1992, all gasoline sold within the Missoula CO nonattainment area must have a minimum oxygen content of 2.7% by weight from November 1st through the last day of February each year. The use of oxygenates in gasoline helps provide additional oxygen in the fuel for better combustion of the fuel in the engine and a decrease in tailpipe CO emissions.

2. Federal Motor Vehicle Control Program (FMVCP). Section 2.3.2.2 of the maintenance plan discusses the FMVCP which involves Federal provisions that require vehicle manufacturers to meet more stringent vehicle emission limitations for new vehicles in future years. These emission limitations are phased in (as a percentage of new vehicles manufactured) over a period of years. As new, lower emitting vehicles replace older, higher emitting vehicles (“fleet turnover”), emission reductions are realized for a particular area such as Missoula.

3. Residential Woodburning. As described in section 2.3.2.3 of the maintenance plan, in order to reduce the amount of CO emissions from residential woodburning, Missoula adopted progressively more stringent solid fuel burning device regulations. Currently, the only new solid fuel burning devices permitted in Missoula are pellet stoves and the regulations also require that most woodstoves be removed at the time of sale of a property.

4. Transportation Infrastructure. Section 2.3.2.4 of the maintenance plan describes the changes in transportation infrastructure that specifically address the B/S/R intersection. Violations of the CO NAAQS were occurring at the B/S/R intersection in the 1980s and an initial intersection reconstruction was completed in 1985. This effort involved restricting left turn lanes and adding right turn and departure lanes. The CO designation of nonattainment for Missoula in 1991 was again tied to monitoring data near the B/S/R intersection. The final reconstruction project involved the realignment of South Avenue such that South Avenue no longer enters the intersection. This construction effort was scheduled to be completed by the end of 2005. The South Avenue realignment simplified the intersection, reducing the projected peak-hour delay from 120 seconds to 20 seconds, and also allowed for the synchronization of all traffic lights along Brooks Street from Reserve to Mount. This reduces congestion along the whole corridor.

5. Outdoor Burning. Section 2.3.2.5 of the maintenance plan describes the provisions of Missoula's outdoor burning regulations. These regulations reduce the impact of outdoor burning, especially during December, January, and February, by requiring a permit for each burn, allowing only the burning of untreated lumber and natural vegetation, requiring burners to call the Outdoor Burning Hotline to confirm if any burning or air quality restrictions are in effect, establishing burning seasons to reduce the generation of smoke, and prohibiting outdoor burning during December, January, and February except for ceremonial bonfires, emergency burning, and essential wintertime burning.

We have evaluated the various Local, State, and Federal control measures, the original 1990 base year CO emission inventory (62 FR 65613, December 15, 1997), the 1993 periodic CO emission inventory, the 1996 periodic CO emission inventory, and the 2000 attainment year CO inventory that was provided with the State's May 27, 2005 submittal and have concluded that the improvement in air quality in the Missoula nonattainment area has resulted from emission reductions that are permanent and enforceable.

(e) Redesignation Criterion: The Area Must Have a Fully Approved Maintenance Plan Under Section 175A of the CAA

Section 107(d)(3)(E)(iv) of the CAA provides that for an area to be redesignated to attainment, the Administrator must have fully approved a maintenance plan for the area meeting the requirements of section 175A of the CAA.

Section 175A of the CAA sets forth the elements of a maintenance plan for areas seeking redesignation from nonattainment to attainment. The maintenance plan must demonstrate continued attainment of the applicable NAAQS for at least ten years after the Administrator approves a redesignation to attainment. Eight years after the promulgation of the redesignation, the State must submit a revised maintenance plan that demonstrates continued attainment for a subsequent ten-year period following the initial ten-year maintenance period. To address the possibility of future NAAQS violations, the maintenance plan must contain contingency measures, with a schedule for adoption and implementation, that are adequate to assure prompt correction of a violation. In addition, we issued further maintenance plan interpretations in the “General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990” (57 FR 13498, April 16, 1992), “General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990; Supplemental” (57 FR 18070, April 28, 1992), and the EPA guidance memorandum entitled “Procedures for Processing Requests to Redesignate Areas to Attainment” from John Calcagni, Director, Air Quality Management Division, Office of Air Quality and Planning Standards, to Regional Air Division Directors, dated September 4, 1992.

In this Federal Register action, EPA is proposing approval of the maintenance plan for the Missoula nonattainment area because we have determined, as detailed below, that the State's maintenance plan meets the requirements of section 175A and is consistent with the documents referenced above. Our analysis of the pertinent maintenance plan requirements, with reference to the Governor's May 27, 2005, submittal, is provided as follows:

1. Emissions Inventories—Attainment Year and Projections

EPA's interpretations of the CAA section 175A maintenance plan requirements are generally provided in the General Preamble (see 57 FR 13498, April 16, 1992) and the September 4, 1992, Calcagni Memorandum referenced above. Under our interpretations, areas seeking to redesignate to attainment for CO may demonstrate future maintenance of the CO NAAQS either by showing that future CO emissions will be equal to or less than the attainment year emissions or by providing a modeling demonstration.

The maintenance plan that the Governor submitted on May 27, 2005, includes comprehensive inventories of CO emissions for the Missoula area. These inventories include emissions from stationary point sources, area sources, non-road mobile sources, and on-road mobile sources. The maintenance plan uses a year 2000 attainment inventory and includes interim-year projections with a final maintenance year of 2020. More detailed descriptions of the 2000 attainment year inventory and the projected inventories are documented in section 2.5.1, section 2.5.2.2, and Appendix D of the maintenance plan. The State's submittal contains detailed emission inventory information that was prepared in accordance with EPA guidance. Summary emission figures from the 2000 attainment year, the interim projected years, and the final maintenance year of 2020 are provided in Table IV-1 below.

Table IV-1.—CO Emission Inventories for the Missoula Area

[All figures in tons per day of CO]

Year	2000	2005	2010	2015	2020
Point Sources	0.30	0.33	0.37	0.41	0.46
Area Sources	6.62	6.37	6.10	5.88	5.69
Non-Road Mobile Sources	5.06	5.73	6.14	6.52	7.01
On-Road Mobile Sources	44.86	32.73	27.10	24.97	22.98
Total	56.83	45.16	39.71	37.78	36.14

2. Demonstration of Maintenance—Projected Inventories and CAL3QHC Intersection Modeling

As we presented above, total CO emissions were projected forward by the State for the years 2005, 2010, 2015, and 2020. We note the State's approach for developing the projected inventories follows EPA guidance on projected emissions and we believe they are acceptable.^[2] Further information regarding these CO emission inventories is also provided in section 2.5.2.2 and in Appendix D of the maintenance plan. The projected inventories show that CO emissions are not estimated to exceed the 2000 attainment level during the time period of 2000 through 2020 and, therefore, the Missoula area has satisfactorily demonstrated maintenance.

In addition to the emission inventory projections, the State also performed “hot-spot” modeling to evaluate predicted CO concentrations at the B/S/R intersection. This effort involved the CAL3QHC-R intersection model and considered meteorological data, relevant CO emission contributions from point, area, non-road, and on-road sources, and information specific to the B/S/R intersection such as traffic patterns and intersection geometry. Consistent with EPA guidance, the State modeled CO concentrations at 60 receptor sites around the intersection and at the location of the CO ambient air quality monitoring site at the B/S/R intersection. The years modeled were 2000, 2005, 2010, and 2020. We note this modeling effort was consistent with our modeling guidance.

The results of the State's modeling for 2000, 2005, 2010, and 2020 are presented in section 2.5.2.1 and Appendix C of the maintenance plan and in Table IV-2 below.

Table IV-2.—CAL3QHC-R Modeled CO Concentrations for the B/S/R Intersection

[All values are in parts per million]

	2000	2005	2010	2020
First Maximum 8-hour CO Value	11.8	8.9	5.4	4.5
Second Maximum 8-hour CO Value	10.7	8.0	4.4	3.6
First Maximum 8-hour CO Value at the Monitor Location	7.0	5.4	3.2	2.5
Second Maximum 8-hour CO Value at the Monitor Location	6.7	5.1	2.9	2.4

As shown, the CAL3QHC-R model predicted an exceedance of the CO NAAQS in 2000 at a modeling receptor location near the intersection. We consider this to be a conservative estimate by the model. For comparison, for 2000 the model predicted first maximum 8-hour and second maximum 8-hour CO concentrations of 7.0 and 6.7 ppm, respectively, at the ambient air quality monitoring site. However, actual ambient air quality data from the monitor for 2000 were a first maximum 8-hour value of 3.9 ppm and second maximum 8-hour value of 3.3 ppm (ref. section 2.1.1 and Figure 2-3 of the maintenance plan.)

Based on the information provided in sections 2.5.2.1 and 2.5.2.2, the maintenance plan concludes that maintenance of the CO NAAQS is demonstrated. Specifically, the actual monitored values for 2000 indicate no exceedances of the CO NAAQS for the Missoula area, the modeled CO values for 2005, 2010, and 2020 are less than the 8-hour CO NAAQS (9.0 ppm), and, as stated earlier in this action, predicted CO emissions for 2005, 2010, and 2020 are all less than the attainment year levels of 2000.

We have reviewed the State's CAL3QHC-R modeling data and results and the attainment year and projected years CO emission inventory information, and have concluded that the State has satisfactorily demonstrated maintenance of the CO NAAQS through 2020.

3. Monitoring Network and Verification of Continued Attainment

Continued attainment of the CO NAAQS in the Missoula area depends, in part, on the State's efforts to track indicators throughout the maintenance period. This requirement is met in section 2.5.3 of the Missoula CO maintenance plan. In section 2.5.3 the State commits to review mobile source emission inventory data and compare that information to the emission inventory data in the Missoula CO maintenance plan. In section 2.5.3 the State also commits to continue the operation of the CO monitor in the Missoula area, specifically at the B/S/R intersection, and to annually review this monitoring network and make changes as appropriate.

Based on the above, we are approving these commitments as satisfying the relevant requirements and note that this approval will render the State's commitments federally enforceable.

4. Contingency Plan

Section 175A(d) of the CAA requires that a maintenance plan include contingency provisions. To meet this requirement, the State has identified appropriate contingency measures along with a schedule for the development and implementation of such measures.

As stated in section 2.5.5 and 2.5.5.4 of the Missoula CO maintenance plan, the contingency measures for the Missoula area will be triggered by a violation of the CO NAAQS.

Section 2.5.5.4 states that contingency measures contained in the Missoula City-County Air Pollution Control Plan will be implemented within 60 days of notification by the MDEQ and EPA that the area has violated the CO NAAQS. If those measures are not adequate, the Missoula City-County Air Pollution Control Board (MCCAPCB), in conjunction with the Air Quality Advisory Council (AQAC), will initiate a process to begin evaluating potential contingency measures. The Missoula City-County Health Department (MCCHD) and the AQAC will present recommendations to the MCCAPCB within 180 days of notification. The MCCAPCB will then hold a public hearing to consider the contingency measures recommended, along with any other contingency measures that the MCCAPCB believes may be appropriate to effectively address the violation of the CO NAAQS. The necessary contingency measures will be adopted and implemented within one year of the MCCHD being notified of the CO NAAQS violation.

The potential contingency measures that are identified in section 2.5.5.1 of the Missoula CO maintenance plan include (a) expanding the 2.7% oxygenated fuels program in Missoula County to months outside of the current program time frame of November 1st through the end of February, (b) further restricting woodstove burning, (c) increasing the oxygenated fuels content to 3.1% by weight, and (d) constructing transportation projects and implementing transportation control measures. A more complete description of the triggering mechanism and these contingency measures can be found in section 2.5.5 of the Missoula CO maintenance plan.

Based on the above, we find that the contingency plan provided in the Missoula CO maintenance plan meets the requirements of section 175A(d) of the CAA.

5. Subsequent Maintenance Plan Revisions

In accordance with section 175A(b) of the CAA, the MCCHD and MDEQ have committed to submit a revised maintenance plan eight years after our approval of the redesignation. This provision for revising the maintenance plan is contained in section 2.5.7 of the Missoula CO maintenance plan.

V. EPA's Evaluation of the Transportation Conformity Requirements

One key provision of our conformity regulation requires a demonstration that emissions from the transportation plan and Transportation Improvement Program are consistent with the emissions budget(s) in the SIP (40 CFR sections 93.118 and 93.124). The emissions budget is defined as the level of mobile source emissions relied upon in the attainment or maintenance demonstration to maintain compliance with the NAAQS in the nonattainment or maintenance area. The rule's requirements and EPA's policy on emissions budgets are found in the preamble to the November 24, 1993, transportation conformity rule (58 FR 62193-96) and in the sections of the rule referenced above.

Section 2.5.6 of the Missoula CO maintenance plan defines the CO motor vehicle emissions budgets in the Missoula CO maintenance area as 44.86 tons per day for 2005 through 2009, 43.22 tons per day for 2010 through 2019, and 42.67 tons per day for 2020 and beyond. As we explain more fully below, we view these as the budgets for 2000, 2010, and 2020 respectively.

Under our conformity rules, a motor vehicle emissions budget is established for a given year, not for a range of years. This is because the motor vehicle emissions budget reflects the inventory value for motor vehicle emissions in a given year, plus, potentially, any safety margin in that year. (We explain the concept of safety margin more fully below.) It is not possible to specify the same motor vehicle emissions budget for a range of years absent specific analysis supporting the derivation of that budget for each year in the range. As a practical matter, this is not usually important because our conformity rules also say that a motor vehicle emissions budget for a particular year applies for conformity analyses of emissions in that year and all subsequent years before the next budget year. See 40 CFR 93.118(b)(1)(ii) (“Emissions in years for which no motor vehicle emissions budget(s) are specifically established must be less than or equal to the motor vehicle emissions budget(s) established for the most recent prior year.”).

The maintenance plan's “2005 through 2009” motor vehicle emissions budget in fact is derived directly from the year 2000 inventory value for on-road vehicle emissions. It is apparent from the maintenance plan that MCCHD and MDEQ were not relying on 2005 inventory numbers to establish the “2005 through 2009” budget, and thus, it is not truly a 2005 budget. We assume the maintenance plan designates this as a 2005 to 2009 budget because the maintenance plan was adopted in 2005, and the years 2000 through 2004 had already passed. However, because it was derived from 2000 values, the “2005 through 2009” budget is actually a 2000 budget, and we will refer to it as such in the remainder of this proposal. Consistent with our discussion above, the 2000 budget applies for conformity analyses of emissions in the year 2000 and all subsequent years before the next budget year; i.e., since the next budget year is 2010, the 2000 budget applies for analyses of years 2000 through 2009.

Similarly, the “2010 through 2019” and “2020 and beyond” budgets were derived from, respectively, 2010 and 2020 inventory values for on-road vehicle emissions and available safety margin. Thus, we will refer to these as the 2010 and 2020 budgets in the remainder of this proposal.

For the Missoula CO maintenance plan, the “safety margin” is the difference between the attainment year (2000) total emissions and the projected future year's total emissions. Part or all of the safety margin may be added to projected mobile source CO emissions to arrive at a motor vehicle emissions budget to be used for transportation conformity purposes. The safety margins, less one ton per day, were added to projected mobile source CO emissions for 2010, and 2020. The derivation and determination of safety margins and motor vehicle emissions budgets for the Missoula CO maintenance plan is further illustrated in Table V-1 below and in section 2.5.6, Table 2-7 of the maintenance plan:

Table V-1.—Mobile Sources Emissions, Safety Margins, and Motor Vehicle Emissions Budgets in Tons of CO per Day (TPD)

Year	Mobile sources emissions (TPD)	Total emissions (TPD)	Math	Margin of safety (TPD)	Motor vehicle emissions budget (TPD)
2000	44.86	56.83		N/A	44.86
2010	27.10	39.71	56.83-39.71 = 17.12 17.12−1 = 16.12 27.10+16.12 = 43.22	16.12	43.22
2020	22.98	36.14	56.83−36.14 = 20.69 20.69−1 = 19.69 22.98+19.69 = 42.67	19.69	42.67
Note: N/A = Not Applicable.

Our analysis indicates that the above figures are consistent with maintenance of the CO NAAQS throughout the maintenance period. Therefore, we are approving the 44.86 tons per day budget for 2000, 43.22 tons per day budget for 2010, and 42.67 tons per day budget for 2020 for the Missoula area.

Pursuant to section 93.118(e)(4) of EPA's transportation conformity rule, as amended, EPA must determine the adequacy of submitted mobile source emissions budgets. EPA reviewed the Missoula CO maintenance plan budgets for adequacy using the criteria in 40 CFR 93.118(e)(4), and determined that the budgets were adequate for conformity purposes. EPA's adequacy determination was made in a letter to the MDEQ on May 4, 2006, and was announced in the Federal Register on June 1, 2006 (71 FR 31181). As a result of this adequacy finding, the budgets took effect for conformity determinations in the Missoula area on June 16, 2006. However, we are not bound by that determination in acting on the maintenance plan.^[3]

VI. Consideration of Section 110(l) of the Clean Air Act

Section 110(l) of the CAA states that a SIP revision cannot be approved if the revision would interfere with any applicable requirement concerning attainment and reasonable further progress towards attainment of a NAAQS or any other applicable requirement of the CAA. The Missoula CO maintenance plan will not interfere with attainment, reasonable further progress, or any other applicable requirement of the CAA.

VII. Proposed Action

In this action, EPA is proposing approval of the request for redesignation from nonattainment to attainment for CO for the Missoula area, the Missoula area's maintenance plan, the 1993 PEI, the 1996 PEI, the year 2000 attainment inventory (which fulfills the 1999 PEI obligation), and the transportation conformity CO motor vehicle emission budgets of 44.86 tons per day for 2000, 43.22 tons per day for 2010, and 42.67 tons per day for 2020.

Submit your comments, identified by Docket ID No. EPA-R08-OAR-2006-0163, by one of the methods identified above at the front of this proposed rule. In deciding on our final action, we will consider your comments if they are received before May 25, 2007. EPA will address all public comments in a subsequent final rule based on this proposed rule. EPA will not institute a second comment period on this action. Any parties interested in commenting must do so at this time.

VIII. Statutory and Executive Order Reviews

Under Executive Order 12866 (58 FR 51735, October 4, 1993), this proposed action is not a “significant regulatory action” and therefore is not subject to review by the Office of Management and Budget. For this reason, this action is also not subject to Executive Order 13211, “Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use” (66 FR 28355, May 22, 2001). This proposed action merely proposes to approve state law as meeting Federal requirements and imposes no additional requirements beyond those imposed by state law. Accordingly, the Administrator certifies that this proposed rule will not have a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.). Because this rule proposes to approve pre-existing requirements under state law and does not impose any additional enforceable duty beyond that required by state law, it does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4).

This proposed rule also does not have tribal implications because it will not have a substantial direct effect on one or more Indian tribes, on the relationship between the Federal Government and Indian tribes, or on the distribution of power and responsibilities between the Federal Government and Indian tribes, as specified by Executive Order 13175 (65 FR 67249, November 9, 2000). This action also does not have Federalism implications because it does not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132 (64 FR 43255, August 10, 1999). This action merely proposes to approve a state rule implementing a Federal standard, and does not alter the relationship or the distribution of power and responsibilities established in the Clean Air Act. This proposed rule also is not subject to Executive Order 13045 “Protection of Children from Environmental Health Risks and Safety Risks” (62 FR 19885, April 23, 1997), because it proposes to approve a state rule implementing a Federal standard.

In reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. In this context, in the absence of a prior existing requirement for the State to use voluntary consensus standards (VCS), EPA has no authority to disapprove a SIP submission for failure to use VCS. It would thus be inconsistent with applicable law for EPA, when it reviews a SIP submission, to use VCS in place of a SIP submission that otherwise satisfies the provisions of the Clean Air Act. Thus, the requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) do not apply. This proposed rule does not impose an information collection burden under the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

List of Subjects

40 CFR Part 52

• Environmental protection
• Air pollution control
• Carbon monoxide
• Intergovernmental relations
• Reporting and recordkeeping requirements

40 CFR Part 81

• Air pollution control
• National parks
• Wilderness areas

Authority: 42 U.S.C. 7401 et seq.

Dated: April 17, 2007.

Kerrigan G. Clough,

Acting Regional Administrator, Region 8.

Footnotes

1.  Refer to EPA's September 4, 1992, John Calcagni policy memorandum entitled “Procedures for Processing Requests to Redesignate Areas to Attainment.”

2.  “Use of Actual Emissions in Maintenance Demonstrations for Ozone and Carbon Monoxide (CO) Nonattainment Areas”, signed by D. Kent Berry, Acting Director, Air Quality Management Division, November 30, 1993.

3.  In its adequacy determination, EPA listed and found adequate budgets for 2005, 2010, and 2021. The listed years should have been 2000, 2010, and 2020, consistent with our discussion above. Assuming we do not change this proposal in response to public comment, the final approved budgets will be for years 2000, 2010, and 2020.