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Proposed Rule

Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality Planning Purposes: Portneuf Valley, Idaho, Area

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Information about this document as published in the Federal Register.

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AGENCY:

Environmental Protection Agency.

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA, Agency, or we) proposes to approve revisions to the Idaho State Implementation Plan (SIP) for particulate matter with an aerodynamic diameter less than or equal to a nominal ten micrometers (PM-10) for the Portneuf Valley nonattainment area. The revisions include a nonattainment area plan that brought the area into attainment by the applicable attainment date of December 31, 1996, a maintenance plan that will provide for maintaining the PM-10 national ambient air quality standards (NAAQS) ten years into the future, and a request to redesignate the Portneuf Valley nonattainment area to attainment for PM-10. We are proposing to approve these revisions because we believe the State adequately demonstrates that the control measures being implemented in the Portneuf Valley result in attainment and maintenance of the PM-10 National Ambient Air Quality Standards and that all other requirements of the Clean Air Act for redesignation to attainment are met.

DATES:

Comments must be received on or before June 20, 2005.

ADDRESSES:

Submit your comments, identified by Docket ID No. R10-OAR-2005-ID-0001, by one of the following methods:

1. Federal eRulemaking Portal: http://www.regulations.gov. Follow the on-line instructions for submitting comments.

2. Agency Web site: http://www.epa.gov/​edocket. EDOCKET, EPA's electronic public docket and comment system, is EPA's preferred method for receiving comments. Follow the on-line instructions for submitting comments.

3. E-mail: r10.aircom@epa.gov.

4. Mail: Office of Air, Waste and Toxics, Environmental Protection Agency, Attn: Steve Body, Mailcode: AWT-107, 1200 Sixth Avenue, Seattle, WA 98101.

5. Hand Delivery: Environmental Protection Agency Region 10, Attn: Steve Body (AWT-107), 1200 Sixth Ave., Seattle, WA 98101, 9th floor mail room. Such deliveries are only accepted during EPA's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. R10-OAR-2005-ID-0001. EPA's policy is that all comments received will be included in the public docket without change, 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 regulations.gov or e-mail. The EPA EDOCKET and the Federal regulations.gov website are 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 EDOCKET or 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.

Docket: All documents in the docket are listed in the EDOCKET index at http://www.epa.gov/​edocket. Although listed in the index, some information may not be publicly available, such as CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in EDOCKET or in hard copy at EPA Region 10, Office of Air Quality, 1200 Sixth Avenue, Seattle, Washington, from 8 a.m. to 4:30 p.m. Monday through Friday, excluding legal holidays. Please contact the individual listed in the FOR FURTHER INFORMATION CONTACT section to schedule your review of these records.

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FOR FURTHER INFORMATION CONTACT:

Steve Body, Office of Air, Waste and Toxics, Region 10, AWT-107, Environmental Protection Agency, 1200 Sixth Ave., Seattle, WA 98101; phone: (206) 553-0782; fax number: (206) 553-0110; e-mail address: body.steve@epa.gov.

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SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Overview

A. What action are we taking?

B. What is the background for this action?

1. Description of Area

2. Description of Air Quality Problem

3. Designation History of the Nonattainment Area

4. SIP Submittal History of the Nonattainment Area

C. What impact does this action have on the Portneuf Valley community?

II. Review of Nonattainment Area Plan

A. What criteria did EPA use to review the nonattainment area plan?

1. New Source Review Permit Program

2. Demonstration of Attainment

3. Reasonably Available Control Measures (RACM) including Reasonably Available Control Technology (RACT)

4. Major Stationary Sources of PM-10 Precursors

5. Emissions Inventory Requirements

6. Enforceable Emission Limitations and Other Control Measures

7. Additional Requirements for Nonattainment Area Plans

B. What do we conclude about the nonattainment area plan?

III. Review of Maintenance Plan

A. What criteria did EPA use to review the maintenance plan?

1. Attainment Emissions Inventory

2. Maintenance Demonstration

3. State Monitoring of Air Quality to Verify Continued Attainment

4. Contingency Measures

5. Transportation Conformity Start Printed Page 29244

6. Additional Requirements for Maintenance Plans

B. What do we conclude about the maintenance plan?

IV. Review of Redesignation Request

A. What criteria did EPA use to review the request for redesignation?

1. Attainment Determination

2. Fully Approved Nonattainment Area Plan

3. Permanent and Enforceable Improvements in Air Quality

4. Other Planning Requirements

5. Section 110 Requirements

6. Part D Requirements

7. Section 172(c) Plan Provisions Requirements

8. Subpart 4 requirements

B. What do we conclude about the request for redesignation?

V. Statutory and Executive Order Reviews

I. General Overview

A. What Action Are We Taking?

We are proposing to approve the State Implementation Plan (SIP) revision for PM-10 submitted on June 30, 2004, by the State of Idaho Division of Environmental Quality (IDEQ) for the Portneuf Valley PM-10 nonattainment area. The revision includes a nonattainment area plan, maintenance plan, and a request to redesignate the Portneuf Valley nonattainment area to attainment for PM-10. We are proposing to approve these two plans and the request for redesignation because we believe the State adequately demonstrates that the control measures being implemented in the Portneuf Valley result in attainment and maintenance of the PM-10 National Ambient Air Quality Standards (NAAQS) and that all other requirements of the Clean Air Act (the Act) for redesignation to attainment are met.

B. What Is the Background for This Action?

1. Description of Area

The Portneuf Valley, Idaho PM-10 nonattainment area is located in southeastern Idaho and includes the Cities of Pocatello and Chubbuck. For a legal description of the boundaries, see 40 CFR 81.313. The nonattainment area covers 96.6 square miles and the combined population of the two cities is approximately 76,000.

The topography of the Portneuf Valley area is complex. The City of Pocatello lies in the Portneuf Valley at an elevation of approximately 4500 feet. The Pocatello Mountain Range, with elevations reaching 9000 feet above mean sea level (MSL), forms the east side of the Valley and the Bannock Mountain Range, reaching 7500 feet above MSL, lies to the west. The Portneuf Valley empties into the Snake River plain.

The Portneuf Valley is arid with significant variation in temperature between winter and summer seasons. Winter average temperature is 24.4 degrees Fahrenheit. Winter and spring are characterized by brisk southwest winds of 20 to 30 miles per hour (mph) which often persist for days. Migratory weather disturbances are greatly influenced by the complex terrain, making prediction of wind flow patterns difficult. Periodically, stagnate air conditions are established for a period of several days that can lead to elevated PM-10 levels. July is the warmest month with an average temperature of 69.2 degrees Fahrenheit. Annual rainfall of 12.5 inches is distributed throughout the year with a maximum in the spring. Average snow fall is 41.7 inches.

2. Description of Air Quality Problem

The highest PM-10 levels in the Portneuf Valley nonattainment area occur in the winter. Cold temperature, high relative humidity, and fog are conducive to sulfur dioxide (SO2) rapidly reacting with ammonia in the atmosphere to create ammonium sulfate. Also during these conditions, oxides of nitrogen (NOX) react with ammonia to create ammonium nitrate. These winter conditions are also often associated with stagnation episodes. Very little ventilation occurs through vertical mixing or by horizontal transport out of the valley. Without a means of ventilation, PM-10 levels increase day-to-day from both primary and secondary formation, and tend to peak by the third day of a stagnation episode. Sources of primary PM-10 are J.R. Simplot, re-entrained dust from paved roads, agricultural activity, residential/commercial construction, non-agricultural windblown dust, and to a lesser extent, residential combustion and motor vehicles. Sources of precursor emissions resulting in secondary PM-10 formation are from one stationary source and to a limited extent, motor vehicles (cars, trucks, and locomotives).

Secondary PM-10 in the Portneuf Valley has been measured during these winter stagnation events at more than 50 percent of the total PM-10 mass. In extreme events, snow cover is present for an extended period which increases radiative cooling and maintains temperature near or below the freezing point, heightens the strength and depth of the deep stable layer, and promotes the formation of valley fog. The breakup of the stagnation episode is usually accompanied by precipitation.

3. Designation History of the Nonattainment Area

On July 1, 1987, (52 FR 24634), the Environmental Protection Agency revised the NAAQS for particulate matter with a new indicator that includes only those particles with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM-10). See 40 CFR 50.6. The 24-hour primary PM-10 standard is 150 micrograms per cubic meter (μg/m3), with no more than one expected exceedance per year over a three year period. The annual primary PM-10 standard is 50 μg/m3 expected annual arithmetic mean over a three year period. The secondary PM-10 standards are identical to the primary standards.

On August 7, 1987, (52 FR 29383), EPA identified a number of areas across the country as PM-10 “Group I” areas of concern, i.e., areas with a 95% or greater likelihood of violating the PM-10 NAAQS and requiring substantial SIP revisions. What is now known as the Portneuf Valley nonattainment area was originally part of a Group I area called “Power-Bannock Counties (Pocatello),” an area subsequently designated as a moderate PM-10 nonattainment area by the Act. See also 56 FR 11101. This original nonattainment area has gone through two boundary changes. First, on June 12, 1995, EPA corrected the “Power-Bannock Counties (Pocatello)” boundaries to more closely represent the air shed in which the City of Pocatello is located. 61 FR 29667. Second, on November 5, 1998, EPA granted a request from the State to divide the nonattainment area (as corrected) into two areas separated by the Fort Hall Indian Reservation boundary. 63 FR 59722. The area consisting of land under State jurisdiction is now identified as the Portneuf Valley nonattainment area, and the area consisting of land within the exterior boundary of the Fort Hall Indian Reservation is now identified as the Fort Hall nonattainment area. See 40 CFR 81.313. Today's proposed approval of the nonattainment area plan, maintenance plan, and redesignation request applies only to the Portneuf Valley nonattainment area.

4. SIP Submittal History of the Nonattainment Area

Under the Act, the State of Idaho was required to submit a PM-10 SIP (or “nonattainment area plan”) for the Power-Bannock Counties (Pocatello) nonattainment area for meeting the PM-10 NAAQS. In March 1993, Idaho submitted a PM-10 SIP (1993 SIP) to Start Printed Page 29245meet this requirement. Among other things the 1993 SIP submittal addressed primary particulate and made a finding that PM-10 precursors were an insignificant contributor to violations of the PM-10 standard. Under the Act, control requirements for major stationary sources of PM-10 also apply to major stationary sources of PM-10 precursors, except where such sources do not contribute significantly to PM-10 levels which exceed the standards in the area. However, because PM-10 precursors were not insignificant in the area and the 1993 SIP submittal did not address them, the State was required to submit a revised plan.

On February 26, 1999, the State submitted the “Portneuf Valley Particulate Matter (PM-10) Air Quality Improvement Plan, 1998-1999” (1999 SIP). In June 2000, EPA informed the State that although the 1999 SIP submittal addressed PM-10 precursors, the 1999 SIP submittal was inadequate, specifically with respect to transportation conformity and the motor vehicle emissions budget. The State was required to submit a revised plan.

On June 30, 2004, the State submitted the “Portneuf Valley PM-10 Nonattainment Area State Implementation Plan, Maintenance Plan, and Redesignation Request” (June 30, 2004 SIP submittal). This submittal contains a nonattainment area plan (replacing the State's 1993 and 1999 SIP submittals), a maintenance plan, and a request for redesignation to attainment. We are proposing to approve both plans and the request for designation to attainment based on our evaluation below. See the Technical Support Document (TSD) accompanying this notice for further supporting documentation.

C. What Impact Does This Action Have on the Portneuf Valley Community?

EPA's approval of the State's June 30, 2004, SIP submittal (that is, approval of the nonattainment area plan, maintenance plan, and redesignation request) would result in redesignation of Portneuf Valley to a PM-10 attainment area. A redesignation to attainment would relieve the Portneuf Valley area of certain obligations currently in place because of its nonattainment status. In the event of new sources in the area, minor New Source Review (NSR) and Prevention of Significant Deterioration (PSD) requirements would apply.

Although the SIP revision contains emissions reduction control measures that impact residential wood combustion, roadways, and industrial facilities, these control measures are already in place and are enforceable by the State. Therefore, our approval of these measures now has little or no additional regulatory impact on the Portneuf Valley community.

II. Review of Nonattainment Area Plan

A. What Criteria Did EPA Use To Review the Nonattainment Area Plan?

The air quality planning requirements for moderate PM-10 nonattainment areas are set out in subparts 1 and 4 of Part D, Title I of the Act. The EPA has issued a “General Preamble” describing EPA's preliminary views on the how EPA intends to review SIP's and SIP revisions submitted under Title I of the Act, including those State submittals containing provisions to implement the moderate PM-10 nonattainment area SIP requirements. See generally 57 FR 13498 (April 16, 1992) and 57 FR 18070 (April 28, 1992).

Under section 189(a) of the Act, States containing initial moderate PM-10 nonattainment areas are required to submit an implementation plan that includes the following elements:

1. An approved permit program for construction of new or modified major stationary sources of PM-10.

2. A demonstration that the plan provides for attainment by the applicable attainment date or that attainment by such date is impracticable.

3. Provisions to assure that reasonably available control technology (RACT) is implemented.

Below is a discussion of how the Portneuf Valley nonattainment area plan meets the requirements of section 189(a) and associated requirements in section 172(c)(1) and (5). We also discuss how the nonattainment area plan meets certain other provisions of section 189 and Part D (specifically the PM-10 precursor control provision in section 189(e), the emissions inventory requirement in section 172(c)(3) and the requirement for enforceable control measures in section 110(a)(2)(A)). For discussion of how other requirements in section 189, Part D, and section 110(a)(2) are met, see the TSD accompanying this document.

1. New Source Review Permit Program

Section 189(a)(1)(A) of the Act requires, “For the purpose of meeting the requirements of section 172(c)(5), a permit program providing that permits meeting the requirements of section 173 are required for construction and operation of new and modified major sources of PM-10.”

Section 189(a) and section 172(c)(5) require each nonattainment area plan to provide for permits for the construction and operation of new or modified major stationary sources anywhere in the nonattainment area. The Act requires a permit program for the construction and operation of new and modified major stationary sources of PM-10 located in moderate nonattainment areas (known as “nonattainment area NSR”). EPA approved nonattainment NSR rules for PM-10 nonattainment areas in Idaho on July 23, 1993 (58 FR 39445), and amended provisions were approved by EPA on January 16, 2003 (68 FR 2217). See 60 FR 28726 (June 2, 1995). Therefore, the State has met this permit program requirement.

2. Demonstration of Attainment

Section 189(a)(1)(B) of the Act requires either a demonstration (including air quality modeling) that the plan will provide for attainment by the applicable attainment date or a demonstration that attainment by such date is impracticable.

The initial attainment date for the Power-Bannock Counties (Pocatello) nonattainment area (and therefore the Portneuf Valley nonattainment area) was established by operation of law as no later than December 31, 1994. See section 189(c)(1) of the Act. Section 189(d) of the Act provides criteria by which the Administrator may grant two, 1-year extensions to the attainment date. The State met the requirements for extending the attainment date and EPA granted two 1-year extensions. 61 FR 20730 and 61 FR 66602. Consequently, the attainment date for the Portneuf Valley nonattainment area is December 31, 1996.

To demonstrate attainment, the State relies on a combination of supporting evidence. First it points to ambient air quality monitoring data showing the area attained both the 24-hour and annual PM-10 NAAQS as of December 31, 1996. We published an official finding of attainment by this date in a Federal Register notice on July 5, 2002, 67 FR 48552. Subsequent air monitoring data shows that the area has continued to meet both NAAQS for every three year period since the attainment date. Thus, monitoring data as of and since the attainment date demonstrates attainment of the NAAQS.

Second, the State relies on emissions reduction measures from sources impacting the nonattainment area to bring the area into attainment. These measures include stationary source controls, residential wood burning controls, outdoor burning controls, and road sanding emissions reduction measures. With these measures in place, there have been no further violations of the 24-hour or annual PM-10 NAAQS Start Printed Page 29246in the nonattainment area, thus, providing further support of a demonstration of attainment. Each specific control measure is discussed in more detail in the TSD.

Finally, the State relies on speciated linear rollback modeling. The rollback model uses filter analyses, emissions inventories, and chemical source profiles to assess the impacts of sources and source groups on PM-10 concentrations. For the Portneuf Valley nonattainment area, the model predicts a 24-hour PM-10 level of 146 μg/m3 in 2000, then a decrease to 103 μg/m3 by 2005 followed by a gradual increase up to 111 μg/m3 in 2020. These predicted levels also demonstrate attainment of the NAAQS.

Based on air quality data for the area since the attainment date, control measures that have been implemented without further violation of the NAAQS and speciated linear rollback modeling showing attainment in the year 2000, we conclude that the state has adequately demonstrated attainment of the PM-10 NAAQS.

3. Reasonably Available Control Measures (RACM) Including Reasonably Available Control Technology (RACT)

Section 189(a)(1)(C) of the Act requires that moderate area SIPs contain “reasonably available control measures” (RACM) for the control of PM-10 emissions. Section 172(c)(1) of the Act, in turn, provides that RACM for nonattainment areas shall include “such reductions in emissions from existing sources in the area as may be obtained through the adoption, at a minimum, of reasonably available control technology* * *”. Read together, these provisions require that moderate area PM-10 SIPs include RACM and RACT for existing sources of PM-10 emissions.

The General Preamble provides further guidance on interpretation of the requirement for RACM and RACT. Congress, in enacting the amended Act, did not use the word “all” in conjunction with RACT. Thus, it is possible that a State could demonstrate that an existing source in an area should not be subject to a control technology especially where such a control is unreasonable in light of the specific area's individual attainment needs or is infeasible. EPA recommends that available control technology be applied to those existing sources in the nonattainment area that are reasonable to control in light of the feasibility of such controls and the individual attainment needs of the specific area.

The nonattainment area plan contains a description of available control measures that the State determined to be reasonable. For agricultural area sources, control measures qualifying as RACM include best management practices and land conservation practices for agricultural activities under the Federal Food Security Act of 1985 (FSA), as amended in 1996 and 2002, (see 16 U.S.C. 3801-3862). Control measures for other area sources include a certified wood stove ordinance, a mandatory residential wood combustion curtailment program, tax and other incentives for non-certified wood stove replacements, an air pollution emergency rule (open burning ban) and city, county and state written agreements to reduce road sanding emissions. These measures are consistent with measures identified as RACM in Appendix C to the General Preamble. 57 FR 18070 (April 28, 1992). Federal area source requirements that were relied on by the State and qualify as RACM include Tier 2 Federal Motor Vehicle Emissions requirements. (65 FR 6698, February 10, 2000, as amended on April 13, 2001, June 3, 2002, and December 6, 2002). The State did not rely on emissions reductions from the Federal non-road motor vehicle rule (69 FR 38958, June 29, 2004) or requirements limiting the sulfur content in diesel fuel (66 FR 5002, January 18, 2001). These measures provide additional reductions.

For industrial sources, the nonattainment area plan contains an analysis of RACT for the J.R. Simplot, Don Plant (J.R. Simplot), the single largest industrial source of both primary particulate and precursor emissions in the area. This is the only industrial source for which Idaho assessed RACT because it is the only major stationary source in the nonattainment area. Based on its evaluation, the State determined that construction and installation of additional control technology is not required to implement RACT. However, for some emission units at J.R. Simplot, the State established more restrictive emission limits. These new emission limits are reasonable because the source has already demonstrated that it is meeting these limits and require no additional cost to the source. The State included the new limits in a Tier II operating permit #077-00006 and has submitted the permit as part of the June 30, 2004 SIP revision. See the TSD accompanying this notice for additional discussion of the permit limits.

The State also relies on emissions reductions from Astaris (FMC), an elemental phosphorus facility located in the adjacent Fort Hall nonattainment area. Astaris (FMC) was a major source of PM-10 and PM-10 precursors until it permanently ceased manufacturing operations in 2001.

Based on Appendix C in the General Preamble, the State's evaluation of RACT and RACM for sources contributing to PM-10 concentrations in the nonattainment area, and the individual attainment needs of this specific area, we conclude that the State has met the requirements for implementing RACM and RACT on sources of PM-10 and precursor emissions in the non-attainment area.

4. Major Stationary Sources of PM-10 Precursors

Section 189(e) of the Clean Air Act provides that control requirements for major stationary sources of PM-10 shall also apply to major stationary sources of PM-10 precursors, except where the Administrator determines that such sources do not contribute significantly to PM-10 levels which exceed the standards in the area. Secondary ammonium sulfate and ammonium nitrate are a significant fraction of the highest PM-10 concentrations reported for the Portneuf Valley nonattainment area. J.R. Simplot is the only major stationary source of these precursor emissions in the area. Therefore, RACT (discussed above) has been established for J.R. Simplot. In light of the control requirements established for this major stationary source of PM-10 precursors, we conclude that the requirements of Section 189(e) are met.

5. Emissions Inventory Requirements

Section 172(c)(3) requires each plan to include a comprehensive, accurate, current inventory of actual emissions from all sources of the relevant pollutants in such area. From this inventory, emissions can be compared to measured air quality to estimate emissions reductions needed to attain the standard if violations of the standard are reported. Where measured air quality is below the standard, the comparison can be used to estimate how much emissions may be allowed to increase and still protect the ambient air quality standard. Emissions estimates are also a key component to predicting future air quality through use of dispersion modeling. The inventory should be consistent with EPA's most recent guidance on emissions inventories for nonattainment areas available at the time and should include the emissions during the time period associated with the monitoring data showing attainment.

Idaho selected calendar year 2000 for the emissions inventory because it represents the most recent year for which valid ambient air quality data Start Printed Page 29247was available. The emissions inventory covers all sources within the boundaries of the nonattainment area, and also includes sources outside the boundaries of the nonattainment area for purposes of dispersion modeling. The inventory includes direct sources of PM-10 as well as sources of the following precursors to PM-10: ammonia, nitrogen oxides, sulfur oxides, and volatile organic compounds. The sources covered by the inventory fall into four major source categories: Point sources, area sources, on-road mobile sources, and non-road mobile sources.

The largest contributors of primary PM-10 and precursor emissions within the nonattainment area for 2000 are as follows:

PM-10: J.R. Simplot, re-entrained dust from paved roads, agricultural activity, residential/commercial construction, non-agricultural windblown dust

NOX: J.R. Simplot, On-road and non-road mobile sources (including locomotives)

SOx: J.R. Simplot

NH3: J.R. Simplot

VOC: J.R. Simplot, solvent usage, gasoline marketing, biogenic, residential/commercial construction, on-road and non-road mobile

We have reviewed the emissions inventory and have found the methods used to develop it are consistent with EPA guidelines. In addition, the assumptions and calculations were checked and found to be thorough and comprehensive.

In summary, the State has adequately developed an emissions inventory for 2000 that identifies the levels of emissions of PM-10 in the nonattainment area as sufficient to attain the NAAQS. Thus, we conclude the inventory meets the inventory requirements for a nonattainment area plan.

6. Enforceable Emission Limitations and Other Control Measures

Section 110(a)(2)(A) requires the plan to include enforceable emission limitations and other control measures as may be necessary or appropriate to meet the applicable requirements of this Act. As discussed above, the area is using agricultural best management practices, motor vehicle fuel emissions standards, residential wood combustion ordinances, road sanding agreements, and an operating permit for J.R. Simplot to meet RACT/RACM requirements. Agricultural best management practices and motor vehicle fuel emissions standards are called for through Federal legislation or regulations. The wood stove curtailment programs is implemented through enforceable city ordinances in coordination with IDEQ. The stationary source emission limits are included in permits issued under a Federally-approved and enforceable operating permit program. Although the winter road sanding and de-icing agreements with county and municipal governments are not enforceable, they have been consistently followed in the 10 years since the agreements were first made in 1993 because of economic advantages. In light of the regulations, ordinances, and agreements and other things in place to ensure these control measures are implemented, we conclude that the requirements of section 110(a)(2)(A) have been met.

7. Additional Requirements for Nonattainment Area Plans

In addition to the core requirements of section 189(a)(1) discussed above, other provisions of the Act in section 172(c) and 110(a) need to be met in order to approve the nonattainment area plan. The additional requirements and how the Portneuf Valley nonattainment area plan meets these requirements is discussed in the TSD accompanying this document.

B. What Do We Conclude About the Nonattainment Area Plan?

Based on our review of the Portneuf Valley nonattainment area plan submitted by the State on June 30, 2004, we conclude that the requirements for an approvable nonattainment area plan under the Act have been met. Therefore, we are proposing approval of the nonattainment area plan submitted for the Portneuf Valley PM-10 nonattainment area.

III. Review of Maintenance Plan

A. What Criteria Did EPA Use To Review the Maintenance Plan?

Section 107(d)(3)(E) of the Act stipulates that for an area to be redesignated to attainment, EPA must fully approve a maintenance plan which meets the requirements of section 175A. Section 175A defines the general framework of a maintenance plan, which must provide for maintenance, i.e., continued attainment, of the relevant NAAQS in the area for at least ten years after redesignation. The following is a list of core provisions required in an approvable maintenance plan.

1. The State must develop an attainment emissions inventory to identify the level of emissions in the area which is sufficient to attain the NAAQS.

2. The State must demonstrate maintenance of the NAAQS.

3. The State must verify continued attainment through operation of an appropriate air quality monitoring network.

4. The maintenance plan must include contingency provisions to promptly correct any violation of the NAAQS that occurs after redesignation of the area.

As explained below, Idaho has complied with each of these requirements in the PM-10 maintenance plan for the Portneuf Valley nonattainment area.

1. Attainment Emissions Inventory

The State should develop an attainment emissions inventory to identify the level of emissions in the area which is sufficient to attain the NAAQS. Where the State has made an adequate demonstration that air quality has improved as a result of the control measures in the SIP, the attainment inventory will generally be an inventory of actual emissions at the time the area attained the standards. This inventory should be consistent with EPA's most recent guidance on emissions inventories for nonattainment areas available at the time and should include the emissions during the time period associated with the monitoring data showing attainment.

The emissions inventory submitted for the Portneuf Valley nonattainment area plan also meets the attainment inventory requirements for a maintenance plan. See our evaluation of the emissions inventory for the nonattainment area plan in section II. The emissions inventory is for the year 2000, a time period associated with the monitoring data showing attainment. (Attainment is associated with all three periods: 1998-2000, 1999-2001, and 2000-2002). We have reviewed this inventory and found the methodology used to develop it is consistent with EPA guidelines. In addition, the assumptions and calculations were checked and found to be thorough and comprehensive.

In summary, the State has adequately developed an attainment emissions inventory for 2000 that identifies the levels of emissions of PM-10 in the nonattainment area as sufficient to attain the NAAQS. Thus, we conclude the State has met the attainment emissions inventory requirements for the Portneuf Valley PM-10 maintenance plan.

2. Maintenance Demonstration

A State may generally demonstrate maintenance of the NAAQS by either Start Printed Page 29248showing that future emissions of a pollutant or its precursors will not exceed the level of the attainment inventory, or by modeling to show that the future mix of sources or its precursors will not exceed the level of the attainment inventory, or by modeling to show that the future mix of sources and emission rates will not cause a violation of the NAAQS. Under the Act, many areas were required to submit modeled attainment demonstrations to show that the proposed reduction in emissions will be sufficient to attain the applicable NAAQS. For these areas, the maintenance demonstration should be based upon the same level of modeling. In areas where no such modeling was required, the state should be able to rely on the attainment inventory approach. In both instances, the demonstration should be for a period of 10 years following the redesignation.

Idaho uses several analytical tools to demonstrate maintenance for the Portneuf Valley PM-10 nonattainment area. These tools include dispersion modeling, trend analysis, chemical mass balance source apportionment and linear speciated roll forward modeling. Several tools are used because no single analytical approach was determined to be appropriate for this area. As discussed earlier, the air quality problem and atmospheric processes in the Portneuf Valley area are complex. The highest PM-10 levels in the area occur in the winter, when cold temperatures, high relative humidity, and fog are conducive to the formation of secondary aerosols. The sources contributing to the PM-10 levels are primary PM-10 and precursor emissions. Sources of primary PM-10 are J.R. Simplot, re-entrained dust from paved roads, agricultural activity, residential/commercial construction, non-agricultural windblown dust, and to a lesser extent, residential combustion and motor vehicles. Precursor emissions are from primarily stationary sources and to a limited extent, motor vehicles (cars, trucks, and locomotives). The topography of the Portneuf Valley area greatly influences migratory weather disturbances, making prediction of wind flow patterns difficult. Periodically, stagnate air conditions are established for a period of several days, which lead to build-up in PM-10 emissions and elevated PM-10 concentrations. Pollutant dispersion during stagnation conditions are difficult to model.

In light of the complexity of the area, the State's reliance on multiple analytical techniques—dispersion modeling, trend analysis, chemical mass balance source apportionment and linear speciated roll forward modeling—is appropriate. When viewed together, the combined results provide an adequate showing that the area will maintain the NAAQS in the future. Our evaluation of each analytical tool and overall conclusion is summarized below.

Dispersion Modeling

Dispersion modeling in the Portneuf Valley area is a challenge due to the complex terrain, meteorology, and the large number and variety of sources emitting primary particulate and precursor emissions. In selecting a model, the State appropriately considered, among other things, whether the model could simulate ambient levels of PM-10 from emissions of primary particulate, atmospheric chemical reactions that form secondary aerosols, complex wind regimes and local scale dispersion and transport. Because of its known capabilities in addressing these and other relevant factors, CALPUFF, an EPA-preferred model listed in appendix W of 40 CFR part 51, was selected.

To assess performance of the model, the State ran CALPUFF to estimate PM-10 levels during worst case meteorological episodes in 1995 and 1999 and compared the predictions to actual measurements. Model performance was mixed. On one hand, estimated PM-10 levels were reasonable given the uncertainties in the meteorological data, the emissions estimates, source characterization and the model's characterization of atmospheric phenomena. On the other hand, certain estimates raised questions and indicated a need for alternative analytical techniques to determine whether maintenance for the area was demonstrated. PM-10 levels were overestimated in the early morning and at night when the inversion was established. In addition, the highest predicted values occurred on days different from the days they were observed. Lastly, questionable levels above the NAAQS in two small areas could not be verified by monitoring data. There was extensive refinement of model inputs to reduce discrepancies but discrepancies still remained.

Because the dispersion model overall provided invaluable information in assessing air quality in the area (i.e., by providing better understanding of sources, transport and fate of PM-10 and hot spot locations), the State still used the model to predict PM-10 concentrations for future years. In these runs, the model showed maintenance of the NAAQS in all areas except the same two questionable areas identified during the performance evaluation. Therefore, alternative analytic tools were used to more fully understand the modeling results and to demonstrate maintenance for the entire nonattainment area.

Ambient Air Quality Data

PM-10 levels have been monitored at several sites across the Portneuf Valley nonattainment area since the mid-1980s. Data from these sites show that the last violation of the 24 hour PM-10 standard was reported in 1995.

Annual PM-10 trends at all sites in the nonattainment area show a continuous improvement in PM-10 air quality since monitoring was initiated. There has been a dramatic decrease in PM-10 levels near the industrial complex of Astaris (FMC) and J.R. Simplot with the addition of controls and the shutdown of the Astaris (FMC) manufacturing operations. Annual average PM-10 concentrations at a site near the industrial complex have dropped from 54 μg/m3 in the late 1980's to 27 μg/m3 in 2001. Air quality has shown continued improvement at the other monitoring sites decreasing from approximately 30 μg/m3 in the late 1980's to 20 μg/m3 in the last few years.

Average 24 hour PM-10 concentrations have shown similar dramatic reductions. Peak PM-10 levels reached 259 μg/m3 at the sewage treatment plant (STP) site and 232 μg/m3 at the Idaho State University (ISU) site in the early 1990's. Peak concentrations are 74 μg/m3 in 2001 at the STP site and 74 μg/m3 in 1999 at the ISU site. The G&G site reported a peak concentration of 204 μg/m3 in 1993 and 79 μg/m3 in 2002.

Ambient data confirms that the control strategies that have been implemented in the Portneuf Valley nonattainment area are effective in reducing PM-10 levels. It is anticipated that additional emissions reductions from State and Federal motor vehicle control programs will continue to result in declining PM-10 levels in the valley. In light of ambient air quality improvement, we conclude that the ambient air quality data supports a demonstration of maintenance.

Meteorological Data

Meteorology analysis shows that improvement in ambient air quality is not due to favorable meteorology. The state analyzed days with meteorology characterized as having poor dispersion conditions. These conditions are characterized by a cold high pressure system with low pressure gradients, low wind speeds, shallow inversions, and little or no precipitation. Although Start Printed Page 29249meteorological data show no discernible annual trend since 1984, the greatest number of days that met poor dispersion conditions criteria occurred in 2001 and 2002. Since there were no exceedances of the NAAQS in 2001 and 2002, this indicates that meteorology has not been a factor in air quality improvement. In light of no discernible trend in meteorology while air quality has improved, we conclude meteorology data provides further support of a demonstration of maintenance for the area.

Emissions Data

An inventory of actual annual emissions was prepared for the base year of 2000 and projected for future years 2010, 2015, and 2020. Calendar year 2000 represents the base year, 2010 represents an intermediary year, 2015 represents the required ten year maintenance year, and 2020 represents the last year of the area's 20 year transportation plan for use in long-term planning.

Historically the highest levels of PM-10 in the Portneuf Valley nonattainment area occur in winter, and are dominated by secondary ammonium sulfate and ammonium nitrate. Therefore, an episodic inventory was prepared for winter conditions. Idaho DEQ selected December 20 through December 26, 1999, which corresponds to an actual air stagnation episode during which three exceedences of the standard were recorded. The 1999 episodic emissions inventory was projected out to future year week-long episodic inventories for 2010, 2015, and 2020. In addition, for each episodic inventory, weekday and weekend day inventories were prepared to account for different levels of activity depending on the day of the week.

When compared to the 2000 base and 1999 episodic inventories, the State predicts the emissions of primary particulate and precursor pollutants will drop in future years 2010, 2015, and 2020. This decrease in emissions is due in large part to the permanent closure of the Astaris (FMC) manufacturing operations that occurred in 2001. In light of this projected decline in overall emissions and our expectation that the Federal non-road motor vehicle rule and requirements limiting the sulfur content in diesel fuel not accounted for by the State will result in further reductions, we conclude that the expected decrease in emissions supports a demonstration of maintenance out to 2015.

Chemical Mass Balance (CMB) Source Apportionment

CMB analysis is a method used to apportion the contribution of different sources to measured PM-10 levels. CMB analysis of PM-10 filters shows that in the base year, over 50% of the PM-10 mass during high episode days in Portneuf Valley was ammonium sulfate. The SO2 emissions, precursors to ammonium sulfate, have since been reduced by more than half with the closure of the FMC manufacturing operations. In addition, Federal rules regulating sulfur content in diesel fuel will dramatically reduce future SO2 emissions from mobile sources.

Future PM-10 concentrations can be estimated using the highest measured PM-10 concentration since 1989 of 177 μg/m3, applying the fraction apportioned to industry and non-industry, and adjusting for emissions reduction or growth. By 2015, industry emissions will decrease by an estimated 60% (compared with base year levels). Emissions from all other sources are anticipated to increase 18%. Predictions using CMB show the projected maximum PM-10 level will be 133 μg/m3 in the year 2020. This level is below the 24-hour PM-10 NAAQS, demonstrating maintenance for the area.

CMB analysis was also used to better understand the discrepancies identified during evaluation of the dispersion model. The source contributions predicted by CMB analysis were compared to the source contributions predicted by the dispersion model. The results suggest that the levels predicted above the NAAQS are due to over-estimation of the contribution of vehicle suspended dust. This over-estimation of motor vehicle emissions may be due to under-prediction of wind speeds in meteorological simulations, thus artificially enhancing the influence of the urban (mobile) sources. It is also plausible that over-predicted concentrations are due to inadequate characterization of coarse particulate matter removal mechanisms which may over-estimate the impact of re-entrained road dust.

Linear Speciated Rollback Modeling

Linear speciated rollback modeling is a simple, spatially averaged mathematical model that assumes a linear relationship between ambient constituents of PM-10 and the area wide emissions of the corresponding constituents. The model dis-aggregates the major airborne particulate components into chemically distinct groups that are emitted by different source types. The model assumes that ambient PM-10 levels are directly proportional to emissions.

Anticipated emissions reductions of primary PM-10, SO2 and NOX result in predicted PM-10 levels below the level of both the annual and 24 hour standards for all future years out to 2020. The maximum 24 hour PM-10 level of 146 μg/m3 occurs in the base year, drops to 106 μg/m3 in 2005 and gradually increases to 111 μg/m3 in 2020. Annual PM-10 levels remain essentially constant at approximately 26 μg/m3 in the base year and 27 μg/m3 in 2020. Because these projected levels are below the PM-10 NAAQS, these results demonstrate maintenance of the area.

In conclusion, dispersion modeling shows that overall the area will meet the PM-10 NAAQS at least 10 years into the future, but that further evaluation is warranted in light of questionable levels predicted in two areas. This further evaluation using trend analysis, chemical mass balance, and linear speciated rollback modeling demonstrates maintenance throughout the nonattainment area. In light of the dispersion modeling results and plausible reasons for the higher levels in two areas, the difficulty of modeling due to the complex conditions of the area, the results from other analytic tools demonstrating maintenance, the anticipated reductions from Federal rules not relied on by the plan, and contingency measures, as discussed below, to be implemented in the event PM-10 levels increase, EPA concludes that the demonstration by the State shows that the Portneuf Valley nonattainment area will maintain the PM-10 NAAQS at least through the maintenance year of 2015.

3. State Monitoring of Air Quality To Verify Continued Attainment

Once an area has been redesignated, the State must continue to operate an appropriate air quality monitoring network in accordance with 40 CFR part 58 to verify the attainment status of the area. The maintenance plan should contain provisions for continued operation of air quality monitors that will provide such verification. In its submittal, the State commits to continue to operate and maintain the network of PM-10 monitoring stations necessary to verify ongoing compliance with the PM-10 NAAQS in the Portneuf Valley nonattainment area.

4. Contingency Measures

Section 175A(d) of the Act requires that a maintenance plan include contingency provisions, as necessary, to correct promptly any violation of the NAAQS that occurs after redesignation. These contingency provisions are distinguished from those generally required for nonattainment areas under section 172(c)(9), which are discussed above. At a minimum, the contingency Start Printed Page 29250provisions must include a commitment that the State will implement all measures contained in the nonattainment area plan prior to redesignation.

The maintenance plan contains three contingency provisions. The first would revise the permit to operate a boiler at the Idaho State University to require a switch of fuel from coal to natural gas during a burn ban. This measure will reduce SO2 emissions and thus reduce ammonium sulfate levels during periods of high PM-10.

The second provision addresses wood smoke emissions. Wood smoke from residential wood stoves has historically been a significant contributor to wintertime PM-10 levels in the Portneuf Valley non-attainment area. The State commits to work with the Cities of Pocatello and Chubbuck to lower the trigger point for implementing a residential wood combustion curtailment program. The current level is 100 μg/m3 PM-10.

Lastly, the State commits to conducting additional analyses of the causes of future reported violations of the standard. Based on the results of that analysis the State will consider the following control measures to resolve the problem:

  • Cover all truck loads that have potential to emit PM-10.
  • Prevent track-out onto paved roads.
  • More restrictions on outdoor burning.
  • Institute a vehicle inspection and maintenance program.
  • Expand the residential wood combustion curtailment programs to include “clean burn” wood stoves.
  • Prohibit construction of unpaved private roads, driveways, or parking lots.
  • Implement transportation control measures.
  • Implement dust control and prevention programs including paving dirt roads and alley ways.

Since the maintenance plan is to cover the 10 year period after Federal approval, it is difficult to completely predict how emissions characteristics will change. This change in the character of the potential PM-10 problem is especially significant toward the “out-years” when the ability to predict the future is difficult. The approach used in the maintenance plan is appropriate since the contingency measures address sources expected to cause problems in the near term and include a commitment to evaluate conditions in the long term.

In light of the control measures relied on by the nonattainment area plan, the identification of additional contingency measures above, and the permanent reductions resulting from the closure of the Astaris (FMC) manufacturing operations, we believe the contingency measure requirements in the Portneuf Valley maintenance plan meet the requirements of Section 175A(d) of the Act.

5. Transportation Conformity

Under section 176(c) of the Act, transportation plans, programs, and projects in nonattainment or maintenance areas, that are developed, funded or approved under title 23 U.S.C. or the Federal Transit Laws, must conform to the applicable SIPs. In short, a transportation plan is deemed to conform to the applicable SIP if the emissions resulting from implementation of that transportation plan are less than, or equal to the motor vehicle emission budget established in the SIP.

In this maintenance plan, procedures for estimating motor vehicle emissions are well documented. Furthermore, the maintenance demonstration modeling results indicated that the estimated motor vehicle emissions for base and future years will not cause or contribute to an exceedance of the NAAQS. Accordingly, we propose to approve the following motor vehicle emissions budgets (MVEB) for PM-10 and its precursors for use in conformity determinations for PM-10 on future Transportation Improvement Programs and Regional Transportation Plans. These mobile source emissions represent a combination of vehicle exhaust, tire wear, brake wear, and road dust.

Portneuf Valley, Idaho PM-10 Motor Vehicle Emissions Budget

YearPM-10 (t/yr)NOX (t/yr)VOC (t/yr)
20058971,575983
20101,1201,085716
20201,364514585

The MVEB was found to be adequate for conformity purposes on August 31, 2004. (69 FR 56052, September 17, 2004.) The Plan provides for reductions in residential wood combustion, road sanding, and industrial emissions. Control measures required by the maintenance plan do not directly include transportation measures as they are not required for the maintenance demonstration.

6. Additional Requirements for Maintenance Plans

In addition to the core requirements of section 175(A) discussed above, other provisions of the Act need to be met in order to approve the maintenance plan. The additional requirements and how the Portneuf Valley maintenance plan meets these requirements is discussed in the TSD accompanying this notice.

B. What Do We Conclude About the Maintenance Plan?

Based on our review of the Portneuf Valley PM-10 maintenance plan submitted by the State on June 30, 2004, we conclude that the requirements for an approvable maintenance plan under the Act have been met. Therefore, we are proposing approval of the maintenance plan submitted for the Portneuf Valley PM-10 nonattainment area.

IV. Review of Redesignation Request

A. What Criteria Did EPA Use To Review the Request for Redesignation?

The criteria used to review the maintenance plan and redesignation request are derived from the Act, the General Preamble, and a policy and guidance memorandum from John Calcagni, September 4, 1992, Procedures for Processing Requests to Redesignate Areas to Attainment. Section 107(d)(3)(E) of the Act states that the EPA can be redesignate an area to attainment if the following conditions are met:

1. The Administrator has determined the area has attained the NAAQS.

2. The Administrator has fully approved the applicable implementation plan under section 110(k).

3. The Administrator has determined that the improvement in air quality is due to permanent and enforceable reductions in emissions.

4. The State has met all applicable requirements for the area under section 110 and Part D.

5. The Administrator has fully approved a maintenance plan, including a contingency plan, for the area under section 175A.

1. Attainment Determination

As discussed earlier, an area has attained the 24-hour PM-10 NAAQS when the average number of expected exceedances per year is less than or equal to one, when averaged over a three year period. To make this determination, three consecutive years of complete ambient air quality data must be collected in accordance with Federal requirements (40 CFR part 58, including appendices). On July 5, 2002, EPA published a finding that the Portneuf Valley PM-10 nonattainment area attained the PM-10 NAAQS by the Start Printed Page 29251applicable attainment date. Subsequent air monitoring data shows that the area has continued to meet both NAAQS for every three year period since the attainment date.

2. Fully Approved Nonattainment Area Plan

States containing initial moderate PM-10 nonattainment areas were required to submit a SIP revision which implements reasonably available control measures (RACM) and demonstrates attainment of the PM-10 NAAQS by the attainment date. The SIP for the area must be fully approved under section 110(k) of the Act, and must satisfy all requirements that apply to the area. In this notice we are proposing to fully approve the nonattainment area plan submitted by the State for the Portneuf Valley PM-10 nonattainment area.

3. Permanent and Enforceable Improvements in Air Quality

The State must be able to reasonably attribute the improvement in air quality to permanent and enforceable reduction in emissions. The State provides a historical analysis of meteorology in the Pocatello area to show that trends in improving air quality are not the result of meteorological conditions. As discussed above, there has been no discernible trend in meteorology while air quality has continued to improve. Therefore we conclude that the improvements in air quality are the result of emissions reductions from the shut down of the Astaris (FMC) manufacturing operations, controls related to road sanding, and the area's wood stove program and not from a change in meteorological conditions.

Based on the State's analysis, and our earlier conclusion that the control measures in place in the nonattainment area are permanent and enforceable, we believe that Idaho has demonstrated air quality improvements are the result of permanent enforceable emissions reductions.

4. Other Planning Requirements

The September 1992 Calcagni memorandum directs states to meet all of the applicable section 110 and Part D planning requirements for redesignation purposes. Thus, EPA interprets the Act to require state adoption and EPA approval of the applicable programs under section 110 and Part D that were due prior to the submission of a redesignation request, before EPA may approve a redesignation request. How the State has met these requirements is discussed below.

5. Section 110 Requirements

Section 110(a)(2) of the Act contains general requirements for implementation plans. These requirements include, but are not limited to, submission of a SIP that has been adopted by the State after reasonable notice and public hearing; provisions for establishment and operation of appropriate apparatus, methods, systems and procedures necessary to monitor ambient air quality; implementation of a permit program; provisions for Part C—Prevention of Significant Deterioration (PSD) and Part D—New Source Review (NSR) permit programs; criteria for stationary source emissions control measures, monitoring and reporting, provisions for modeling; and provisions for public and local agency participation. See the General Preamble for further explanation of these requirements. 57 FR 13498 (April 16, 1992).

For purposes of redesignation, review of the Idaho SIP shows that the State has satisfied all requirements under the Act. Further, in 40 CFR 52.673, EPA has approved Idaho's SIP for the attainment and maintenance of the national standards under Section 110.

6. Part D Requirements

Part D consists of general requirements applicable to all areas which are designated nonattainment based on a violation of the NAAQS. The general requirements are followed by a series of subparts specific to each pollutant. All PM-10 nonattainment areas must meet the applicable general provisions of subpart 1 and the specific PM-10 provisions in subpart 4, “Additional Provisions for Particulate Matter Nonattainment Areas.” The following paragraphs discuss these requirements as they apply to the Portneuf Valley nonattainment area.

7. Section 172(c) Plan Provisions Requirements

Subpart 1, section 172(c) contains general requirements for nonattainment area plans. A thorough discussion of these requirements may be found in the General Preamble. 57 FR 13538 (April 16, 1992). The requirements for reasonable further progress, identification of certain emissions increases, and other measures needed for attainment are satisfied in our proposed approval in this notice of the nonattainment area plan for the Portneuf Valley PM-10 nonattainment area. The requirement for an emissions inventory is satisfied by the completion of inventories for the nonattainment area plan and maintenance plan. The requirements of the Part D New Source Review (NSR) program will be replaced by the Part C Prevention of Significant Deterioration (PSD) program for PM-10 upon the effective date of this redesignation action. The Federally-approved PSD regulations for Idaho can be found at IDAPA 16.01.012,07, as incorporated by reference by EPA on July 28, 1982 (47 FR 32531), and most recently amended on January 16, 2003 (68 FR 2217).

8. Subpart 4 Requirements

Part D, subpart 4, section 189(a), (c) and (e) requirements apply to any moderate nonattainment area before the area can be redesignated to attainment. The requirements which were applicable prior to the submission of the request to redesignate the area must be fully approved into the SIP before redesignating the area to attainment. These requirements are discussed below:

(a) Provisions to assure that RACM was implemented by December 10, 1993;

(b) Either a demonstration that the plan provided for attainment as expeditiously as practicable but not later than December 31, 1994, or a demonstration that attainment by that date was impracticable;

(c) Quantitative milestones which were achieved every 3 years and which demonstrate reasonable further progress (RFP) toward attainment by December 31, 1994; and

(d) Provisions to assure that the control requirements applicable to major stationary sources of PM-10 also apply to major stationary sources of PM-10 precursors, except where the Administrator determined that such sources do not contribute significantly to PM-10 levels which exceed the NAAQS in the area.

In this document EPA is proposing to approve the nonattainment area plan for the Portneuf Valley PM-10 nonattainment area containing the elements meeting requirements (a) through (d) above.

States with PM-10 nonattainment areas were required to submit a permit program for the construction and operation of new and modified major stationary sources of PM-10 by June 30, 1992. States also were to submit contingency measures by November 15, 1993, which become effective without further action by the State or EPA, upon a determination by EPA that the area has failed to achieve RFP or to attain the PM-10 NAAQS by the applicable statutory deadline. See sections Start Printed Page 29252172(c)(9) and 189(a) and 57 FR 13543-13544.

Idaho has presented an adequate demonstration that it has met the requirements applicable to the area under section 110 and Part D. The Part D NSR rules for PM-10 nonattainment areas in Idaho were approved by EPA on July 23, 1993 (58 FR 39445) and amended provisions were approved by EPA on January 16, 2003 (68 FR 2217). The Clean Air Act requires that contingency measures take effect if the area fails to meet reasonable further progress requirements or fails to attain the NAAQS by the applicable attainment date. The Portneuf Valley PM-10 nonattainment area attained the NAAQS for PM-10 by the applicable attainment date of December 31, 1996. Therefore, contingency measures no longer are required under section 172(c)(9) of the Act. Contingency measures are also required for maintenance plans under section 175A(d). Idaho has provided contingency measures in the maintenance plan for the Portneuf Valley PM-10 nonattainment area. The contingency measures in the maintenance plan are discussed in section III above.

B. What Do We Conclude About the Request for Redesignation?

Based on our review of the nonattainment area plan, the maintenance plan, and the request for redesignation request submitted for the Portneuf Valley PM-10 nonattainment area on June 30, 2004, we conclude that all the requirements for redesignation in section 107(d)(3)(E) have been met. Therefore, we are proposing to redesignate the Portneuf Valley PM-10 nonattainment area to attainment.

V. 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 (Public Law 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 substantial direct effects 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 is not economically significant.

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.).

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List of Subjects

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Dated: May 10, 2005.

Julie M. Hagensen,

Acting Regional Administrator, Region 10.

End Signature End Supplemental Information

[FR Doc. 05-10149 Filed 5-19-05; 8:45 am]

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