Source: https://www.federalregister.gov/documents/2007/04/25/E7-7900/approval-and-promulgation-of-air-quality-implementation-plans-state-of-montana-missoula-carbon
Timestamp: 2017-08-24 01:09:13
Document Index: 214864527

Matched Legal Cases: ['art 50', 'art 53', 'art 53', 'art 1', 'art 3', 'art 1', 'art 3', 'art 1', 'art 3']

Comments must be received on or before May 25, 2007.
20480-20488 (9 pages)
FRL-8305-2
(a). What Should I Consider as I Prepare My Comments for EPA?
IV. EPA's Evaluation of the Missoula Redesignation Request and Maintenance Plan
(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
(e) Redesignation Criterion: The Area Must Have a Fully Approved Maintenance Plan Under Section 175A of the CAA
2. Demonstration of Maintenance—Projected Inventories and CAL3QHC Intersection Modeling
https://www.federalregister.gov/d/E7-7900 https://www.federalregister.gov/d/E7-7900
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.
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: videtich.callie@epa.gov and fiedler.kerri@epa.gov.
—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. Start Printed Page 20481
—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.
Kerri Fiedler, Environmental Protection Agency, Region 8, 1595 Wynkoop Street, Denver, Colorado 80202-1129, phone (303) 312-6493, and e-mail at: fiedler.kerri@epa.gov.
(v) The word State means the State of Montana, unless the context indicates otherwise.
(b). Tips for Preparing Your Comments. When submitting comments, remember to:
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 Start Printed Page 20482Missoula 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.
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.
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.
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.
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 Start Printed Page 20483Missoula 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.
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).
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 Start Printed Page 20484emissions 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).
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.
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. Start Printed Page 20485
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:
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]
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
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.Start Printed Page 20486
Table IV-2.—CAL3QHC-R Modeled CO Concentrations for the B/S/R Intersection
[All values are in parts per million]
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.
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.
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.
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.
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.Start Printed Page 20487
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:
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
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]
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.
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 Start Printed Page 20488address 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.
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.
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.
[FR Doc. E7-7900 Filed 4-24-07; 8:45 am]