[Federal Register Volume 70, Number 97 (Friday, May 20, 2005)]
[Proposed Rules]
[Pages 29243-29252]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-10149]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[R10-OAR-2005-ID-0001; FRL-7915-7]


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

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: [email protected].
    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.

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: [email protected].

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

[[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 ([mu]g/
m3), with no more than one expected exceedance per year over 
a three year period. The annual primary PM-10 standard is 50 [mu]g/
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

[[Page 29245]]

meet 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

[[Page 29246]]

in 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 [mu]g/
m3 in 2000, then a decrease to 103 [mu]g/m3 by 
2005 followed by a gradual increase up to 111 [mu]g/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

[[Page 29247]]

was 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

[[Page 29248]]

showing 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 [mu]g/m\3\ in the late 1980's 
to 27 [mu]g/m\3\ in 2001. Air quality has shown continued improvement 
at the other monitoring sites decreasing from approximately 30 [mu]g/
m\3\ in the late 1980's to 20 [mu]g/m\3\ in the last few years.
    Average 24 hour PM-10 concentrations have shown similar dramatic 
reductions. Peak PM-10 levels reached 259 [mu]g/m\3\ at the sewage 
treatment plant (STP) site and 232 [mu]g/m\3\ at the Idaho State 
University (ISU) site in the early 1990's. Peak concentrations are 74 
[mu]g/m\3\ in 2001 at the STP site and 74 [mu]g/m\3\ in 1999 at the ISU 
site. The G&G site reported a peak concentration of 204 [mu]g/m\3\ in 
1993 and 79 [mu]g/m\3\ 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

[[Page 29249]]

meteorological 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 [mu]g/m\3\, 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 [mu]g/m\3\ 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 [mu]g/m\3\ occurs in the base 
year, drops to 106 [mu]g/m\3\ in 2005 and gradually increases to 111 
[mu]g/m\3\ in 2020. Annual PM-10 levels remain essentially constant at 
approximately 26 [mu]g/m\3\ in the base year and 27 [mu]g/m\3\ 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

[[Page 29250]]

provisions 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 [mu]g/
m\3\ 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
------------------------------------------------------------------------
                                         PM-10  (t/  NOX  (t/   VOC  (t/
                  Year                      yr)        yr)        yr)
------------------------------------------------------------------------
2005...................................        897      1,575        983
2010...................................      1,120      1,085        716
2020...................................      1,364        514        585
------------------------------------------------------------------------

    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

[[Page 29251]]

applicable 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

[[Page 29252]]

172(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.).

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Particulate matter, Reporting 
and recordkeeping requirements.

40 CFR Part 81

    Environmental protection, Air pollution control, National parks, 
Wilderness areas.

    Dated: May 10, 2005.
Julie M. Hagensen,
Acting Regional Administrator, Region 10.
[FR Doc. 05-10149 Filed 5-19-05; 8:45 am]
BILLING CODE 6560-50-P