Document ID: EPA-R04-OAR-2013-0562-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: North Carolina; Non-interference Demonstration for Removal of Federal Low-Reid Vapor Pressure Requirement for the Greensboro/Winston-Salem/High Point Area
Posted Date: 2013-11-26T05:00Z

[Federal Register Volume 78, Number 228 (Tuesday, November 26, 2013)]
[Proposed Rules]
[Pages 70516-70525]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-28371]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R04-OAR-2013-0562; FRL-9903-16-Region 4]

Approval and Promulgation of Implementation Plans; North 
Carolina: Non-Interference Demonstration for Removal of Federal Low-
Reid Vapor Pressure Requirement for the Greensboro/Winston-Salem/High 
Point Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to approve the State of North Carolina's 
April 12, 2013, State Implementation Plan (SIP) revision associated 
with the currently approved maintenance plan addressing the 1997 8-hour 
national ambient air quality standards (NAAQS) for the Greensboro/
Winston-Salem/High Point (Triad) Area. Specifically, North Carolina's 
revision, including updated modeling, shows that the Triad Area would 
continue to maintain the 1997 8-hour ozone standard if the currently 
applicable Federal Reid Vapor Pressure (RVP) standard for gasoline of 
7.8 pounds per square inch (psi) were modified to 9.0 psi for four 
portions (Davidson, Forsyth, Guilford and Davie Counties) of the 
``Triad Area'' during the high-ozone season. The State has included a 
technical demonstration with the revision to demonstrate that a

[[Page 70517]]

less-stringent RVP standard of 9.0 psi in these portions of this area 
would not interfere with continued maintenance of the 1997 8-hour Ozone 
NAAQS or any other applicable standard. Approval of this SIP revision 
is a prerequisite for EPA's consideration of an amendment to the 
regulations to remove the aforementioned portions of the Triad Area 
from the list of areas that are currently subject to the Federal 7.8 
psi RVP requirements. In addition, the revised on-road mobile and non-
road mobile source emissions modeling associated with the requested 
modification to the RVP standard results in the use of the updated 
Motor Vehicle Emissions Simulator (MOVES) and NONROAD2008 models which 
are the most current versions of modeling systems available for these 
sources. EPA has preliminarily determined that North Carolina's April 
12, 2013, SIP revision with respect to the revisions to the modeling 
and associated technical demonstration associated with the State's 
request for the removal of the Federal RVP requirements, and with 
respect to the updated on-road mobile, non-road mobile and area source 
emissions, is consistent with the applicable provisions of the Clean 
Air Act (CAA or Act). Should EPA decide to remove the subject portions 
of the Triad Area from those areas subject to the 7.8 psi Federal RVP 
requirements, such action will occur in a subsequent rulemaking.

DATES: Written comments must be received on or before December 26, 
2013.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-
R04-OAR-2013-0562 by one of the following methods:
    1. www.regulations.gov: Follow the on-line instructions for 
submitting comments.
    2. Email: R4-RDS@epa.gov.
    3. Fax: (404) 562-9019.
    4. Mail: EPA-R04-OAR-2013-0562, Regulatory Development Section, Air 
Planning Branch, Air, Pesticides and Toxics Management Division, U.S. 
Environmental Protection Agency, Region 4, 61 Forsyth Street SW., 
Atlanta, Georgia 30303-8960.
    5. Hand Delivery or Courier: Ms. Lynorae Benjamin, Chief, 
Regulatory Development Section, Air Planning Branch, Air, Pesticides 
and Toxics Management Division, U.S. Environmental Protection Agency, 
Region 4, 61 Forsyth Street SW., Atlanta, Georgia 30303-8960. Such 
deliveries are only accepted during the Regional Office's normal hours 
of operation. The Regional Office's official hours of business are 
Monday through Friday, 8:30 a.m. to 4:30 p.m., excluding Federal 
holidays.
    Instructions: Direct your comments to Docket ID No. EPA-R04-OAR-
2013-0562. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit through www.regulations.gov or 
email, information that you consider to be CBI or otherwise protected. 
The www.regulations.gov Web site is an ``anonymous access'' system, 
which means EPA will not know your identity or contact information 
unless you provide it in the body of your comment. If you send an email 
comment directly to EPA without going through www.regulations.gov, your 
email address will be automatically captured and included as part of 
the comment that is placed in the public docket and made available on 
the Internet. If you submit an electronic comment, EPA recommends that 
you include your name and other contact information in the body of your 
comment and with any disk or CD-ROM you submit. If EPA cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment. Electronic 
files should avoid the use of special characters, any form of 
encryption, and be free of any defects or viruses. For additional 
information about EPA's public docket visit the EPA Docket Center 
homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket: All documents in the electronic docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, i.e., 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 www.regulations.gov or 
in hard copy at the Regulatory Development Section, Air Planning 
Branch, Air, Pesticides and Toxics Management Division, U.S. 
Environmental Protection Agency, Region 4, 61 Forsyth Street SW., 
Atlanta, Georgia 30303-8960. EPA requests that if at all possible, you 
contact the person listed in the FOR FURTHER INFORMATION CONTACT 
section to schedule your inspection. The Regional Office's official 
hours of business are Monday through Friday, 8:30 a.m. to 4:30 p.m., 
excluding federal holidays.

FOR FURTHER INFORMATION CONTACT: Sean Lakeman of the Regulatory 
Development Section, in the Air Planning Branch, Air, Pesticides and 
Toxics Management Division, U.S. Environmental Protection Agency, 
Region 4, 61 Forsyth Street SW., Atlanta, Georgia 30303-8960. Mr. 
Lakeman may be reached by phone at (404) 562-9043, or via electronic 
mail at lakeman.sean@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. What is being proposed?
II. What is the background of the Triad Area?
III. What is the history of the gasoline volatility requirement?
IV. What are the section 110(l) requirements?
V. What is EPA's analysis of North Carolina's submittal?
VI. Proposed Action
VII. Statutory and Executive Order Reviews

I. What is being proposed?

    The Triad Area in North Carolina is currently designated attainment 
for the 1997 8-hour ozone NAAQS. The Area was redesignated from 
nonattainment of the 1997 8-hour ozone NAAQS on April 2, 2008. See 73 
FR 17897. This rulemaking proposes to approve a revision to the Section 
110(a)(1) Maintenance Plan for 1997 8-hour ozone standard for the Triad 
Area submitted by the North Carolina Department of Environment and 
Natural Resources (NC DENR). Specifically, EPA is proposing to approve 
revisions to the maintenance plan, including updated modeling, that 
show the Triad Area can continue to maintain the 1997 ozone standard 
without reliance on emissions reductions based upon the use of gasoline 
with an RVP of 7.8 psi in any of the Triad Area counties during the 
high ozone season--June 1 through September 15.\1\ EPA is also 
proposing to conclude that the new modeling demonstrates that the area 
would continue to attain the 1997 8-hour ozone standard with the use of 
gasoline with

[[Page 70518]]

an RVP of 9.0 psi throughout the Triad Area during the high ozone 
season. Consistent with section 110(l) of the Act, EPA also proposes to 
conclude that the use of gasoline with an RVP of 9.0 psi throughout the 
Triad Area during the high ozone season would not interfere with other 
applicable requirements.
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    \1\ As discussed further below, a separate rulemaking is 
required for relaxation of the current requirement to use gasoline 
with an RVP of 7.8 psi in the Area. This action proposes EPA's 
evaluation of the approvability of Florida's revision to the 
maintenance plan pursuant to section 110(l). The decision regarding 
removal of Federal RVP requirements pursuant to section 211(h) in 
the Area includes other considerations evaluated at the discretion 
of the Administrator. As such, the determination regarding whether 
to remove the Area from those areas subject to the section 211(h) 
requirements is made through a separate rule making action.
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    The new modeling conducted by North Carolina to account for the 
proposed relaxation of the applicable RVP standard in portions of the 
Triad Area also results in changes to the on-road mobile, non-road 
mobile and area source emissions associated with the maintenance 
plan.\2\ As such, the North Carolina revision updates the on-road 
mobile, non-road mobile and area source emissions for the Triad Area. 
EPA is also proposing approval of this revision.
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    \2\ In addition to a less stringent RVP standard, the new 
modeling also utilizes updated models for on-road and off-road 
mobile emission sources.
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    This preamble is hereafter organized into five parts. Section II 
provides the background of the Triad Area designation status with 
respect to the various Ozone NAAQS. Section III describes the 
applicable history of federal gasoline regulation. Section IV provides 
the Agency's policy regarding relaxation of the volatility standards. 
Section V provides EPA's analysis of the information submitted by North 
Carolina to support a relaxation of the more stringent volatility 
standard in the Triad Area and revisions to the on-road mobile, nonroad 
mobile and area source emissions associated with Maintenance Plan for 
the Triad Area and provides EPA's analysis regarding the proposed 
revision.

II. What is the background of the Triad Area?

    On November 6, 1991 (56 FR 56694), EPA designated the Counties of 
Davidson, Forsyth and Guilford in their entirety and the portion of 
Davie County bounded by the Yadkin River, Dutchmans Creek, North 
Carolina Highway 801, Fulton Creek and back to Yadkin River in the 
Triad Area as Moderate nonattainment for the 1-hour ozone NAAQS. Among 
the requirements applicable to nonattainment areas for the 1-hour ozone 
NAAQS was the requirement to meet certain volatility standards (known 
as Reid Vapor Pressure or RVP) for gasoline sold commercially. See 55 
FR 23658 (June 11, 1990). As discussed in greater detail below, as part 
of the RVP requirements associated with the nonattainment designation, 
gasoline sold in the Triad 1-hour nonattainment area could not exceed 
7.8 psi RVP during the high-ozone season months.
    Following implementation of the 7.8 psi RVP requirement in the 
Triad Area, on September 9, 1993, the Triad Area was redesignated to 
attainment for the 1-hour ozone NAAQS, based on 1989-1992 ambient air 
quality monitoring data. See 58 FR 47391. North Carolina's November 13, 
1992, 1-hour ozone redesignation request did not include a request for 
the removal of the 7.8 psi RVP standard. The requirements remained in 
place for the Area when it was designated nonattainment for the 1997 8-
hour ozone NAAQS that was promulgated on July 18, 1997, and later 
designated attainment for the 2008 8-hour ozone NAAQS that was 
promulgated March 12, 2008. See 77 FR 30088, May 21, 2012.
    On April 30, 2004, EPA designated and classified areas for the 1997 
8-hour ozone NAAQS (69 FR 23857) unclassifiable/attainment or 
nonattainment for the new 8-hour ozone NAAQS. The Triad Area was 
designated as nonattainment with a deferred effective date as part of 
the Early Action Compact (EAC) \3\ program. (For more information on 
the EAC program, see, http://www.epa.gov/airquality/eac/fs20080331_eac.html.) The Greensboro-Winston Salem-High Point nonattainment-
deferred EAC Area for the 1997 8-hour ozone NAAQS expanded the Triad 
Area to include the entire county of Davie, and Alamance, Caswell, 
Randolph, and Rockingham Counties in their entirety. The Greensboro-
Winston Salem-High Point EAC Area attained the 1997 8-hour ozone NAAQS 
with a design value of 0.083 parts per million (ppm) using three years 
of quality assured data for the years of 2005-2007. On February 6, 
2008, EPA proposed that 13 nonattainment areas with deferred effective 
dates, including the Greensboro-Winston Salem-High Point Area, be 
designated attainment for the 1997 8-hour ozone NAAQS. See 73 FR 6863. 
These areas met all of the milestones of the EAC program and 
demonstrated that they were in attainment of the 1997 8-hour ozone 
NAAQS as of December 31, 2007. This rulemaking was finalized on April 
2, 2008. See 73 FR 17897. Effective April 15, 2008, the Greensboro-
Winston Salem-High Point EAC Area was designated as attainment for the 
1997 8-hour ozone NAAQS. However, these attainment areas consequently 
were required to submit a 10-year maintenance plan under section 
110(a)(1) of the CAA. As required, these plans provide for continued 
attainment and maintenance of the 1997 8-hour ozone NAAQS for at least 
10 years from the effective date of these areas' designation as 
attainment for the 1997 8-hour ozone NAAQS. These plans also include 
components illustrating how each area will continue to attain the 1997 
8-hour ozone NAAQS and provided contingency measures.
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    \3\ An EAC is an agreement between a State, local governments 
and EPA to implement measures not necessarily required by the Act in 
order to achieve cleaner air as soon as possible. The program was 
designed for areas that approach or monitor exceedances of the 8-
hour ozone standard, but are in attainment for the 1-hour ozone 
NAAQS.
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III. What is the history of the gasoline volatility requirement?

    On August 19, 1987 (52 FR 31274), EPA determined that gasoline 
nationwide had become increasingly volatile, causing an increase in 
evaporative emissions from gasoline-powered vehicles and equipment. 
Evaporative emissions from gasoline, referred to as volatile organic 
compounds (VOC), are precursors to the formation of tropospheric ozone 
and contribute to the nation's ground-level ozone problem. Exposure to 
ground-level ozone can reduce lung function (thereby aggravating asthma 
or other respiratory conditions), increase susceptibility to 
respiratory infection, and may contribute to premature death in people 
with heart and lung disease.
    The most common measure of fuel volatility that is useful in 
evaluating gasoline evaporative emissions is RVP. Under section 211(c) 
of CAA, EPA promulgated regulations on March 22, 1989 (54 FR 11868), 
that set maximum limits for the RVP of gasoline sold during the high 
ozone season. These regulations constituted Phase I of a two-phase 
nationwide program, which was designed to reduce the volatility of 
commercial gasoline during the summer ozone control season. On June 11, 
1990 (55 FR 23658), EPA promulgated more stringent volatility controls 
as Phase II of the volatility control program. These requirements 
established maximum RVP standards of 9.0 psi or 7.8 psi (depending on 
the State, the month, and the area's initial ozone attainment 
designation with respect to the 1-hour ozone NAAQS during the high 
ozone season).
    The 1990 CAA Amendments established a new section, 211(h), to 
address fuel volatility. Section 211(h) requires EPA to promulgate 
regulations making it unlawful to sell, offer for sale, dispense, 
supply, offer for supply, transport, or introduce into commerce 
gasoline with an RVP level in excess of 9.0 psi during the high ozone 
season. Section 211(h) prohibits EPA from

[[Page 70519]]

establishing a volatility standard more stringent than 9.0 psi in an 
attainment area, except that EPA may impose a lower (more stringent) 
standard in any former ozone nonattainment area redesignated to 
attainment.
    On December 12, 1991 (56 FR 64704), EPA modified the Phase II 
volatility regulations to be consistent with section 211(h) of the CAA. 
The modified regulations prohibited the sale of gasoline with an RVP 
above 9.0 psi in all areas designated attainment for ozone, beginning 
in 1992. For areas designated as nonattainment, the regulations 
retained the original Phase II standards published on June 11, 1990 (55 
FR 23658).
    As stated in the preamble to the Phase II volatility controls and 
reiterated in the proposed change to the volatility standards published 
in 1991, EPA will rely on states to initiate changes to EPA's 
volatility program that they believe will enhance local air quality 
and/or increase the economic efficiency of the program within the 
statutory limits.\4\ In those rulemakings, EPA explained that the 
governor of a state may petition EPA to set a volatility standard less 
stringent than 7.8 psi for some month or months in a nonattainment 
area. The petition must demonstrate such a change is appropriate 
because of a particular local economic impact and that sufficient 
alternative programs are available to achieve attainment and 
maintenance of the 1-hour ozone NAAQS. A current listing of the RVP 
requirements for states can be found on EPA's Web site at: http://www.epa.gov/otaq/fuels/gasolinefuels/volatility/standards.htm.
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    \4\ See 55 FR 23658 (June 11, 1990), 56 FR 24242 (May 29, 1991) 
and 56 FR 64704 (Dec. 12, 1991).
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    As explained in the December 12, 1991 (56 FR 64704), Phase II 
rulemaking, EPA believes that relaxation of an applicable RVP standard 
is best accomplished in conjunction with the redesignation process. In 
order for an ozone nonattainment area to be redesignated as an 
attainment area, section 107(d)(3) of the Act requires the state to 
make a showing, pursuant to section 175A of the Act, that the area is 
capable of maintaining attainment for the ozone NAAQS for ten years 
after redesignation. Depending on the area's circumstances, this 
maintenance plan will either demonstrate that the area is capable of 
maintaining attainment for ten years without the more stringent 
volatility standard or that the more stringent volatility standard may 
be necessary for the area to maintain its attainment with the ozone 
NAAQS. Therefore, in the context of a request for redesignation, EPA 
will not relax the volatility standard unless the state requests a 
relaxation and the maintenance plan demonstrates, to the satisfaction 
of EPA, that the area will maintain attainment for ten years without 
the need for the more stringent volatility standard. As noted above, 
however, North Carolina did not request relaxation of the applicable 
7.8 psi RVP standard when the Triad Area was redesignated to attainment 
for the either the 1-hour or the 1997 8-hour ozone NAAQS. Rather, North 
Carolina is now seeking to relax the 7.8 psi RVP standard after the 
Triad Area has been redesignated to attainment for the 1997 8-hour 
ozone NAAQS. Accordingly, the original modeling and maintenance 
demonstration supporting the 1997 8-hour ozone maintenance plan must be 
revised to reflect continued attainment under the relaxed 9.0 psi RVP 
standard that the State has requested.

IV. What are the section 110(l) requirements?

    Section 110(l) requires that a revision to the SIP not interfere 
with any applicable requirement concerning attainment and reasonable 
further progress (RFP) (as defined in section 171), or any other 
applicable requirement of the Act. EPA's criterion for determining the 
approvability of North Carolina's April 12, 2013, SIP revision is 
whether this requested action complies with section 110(l) of the CAA. 
Because the modeling associated with the current maintenance plan for 
North Carolina is premised in part upon the 7.8 psi RVP requirements, a 
request to revise the maintenance plan modeling to no longer rely on 
the 7.8 psi RVP requirement is subject to the requirements of CAA 
section 110(l). Therefore, the State must demonstrate that this 
revision will not interfere with the attainment or maintenance of any 
of the NAAQS or any other applicable requirement of the CAA.
    This section 110(l) non-interference demonstration is a case-by-
case determination based upon the circumstances of each SIP revision. 
EPA interprets 110(l) as applying to all NAAQS that are in effect, 
including those that have been promulgated but for which the EPA has 
not yet made designations. The specific elements of the 110(l) analysis 
contained in the SIP revision depend on the circumstances and emissions 
analyses associated with that revision. EPA's analysis of North 
Carolina's April 12, 2013, SIP revision, including review of section 
110(l) requirements is provided below.
    Finally, EPA notes that this rulemaking is only proposing to 
approve the State's revision to its existing maintenance plan for the 
Triad Area showing that the area can continue to maintain the standard 
without relying upon gasoline with an RVP of 7.8 psi being sold in the 
Triad Area during the high ozone season. Consistent with CAA section 
211(h) and the Phase II volatility regulations a separate rulemaking is 
required for relaxation of the current requirement to use gasoline with 
an RVP of 7.8 psi in the Triad Area.

V. What is EPA's analysis of North Carolina's submittal?

a. Overall Preliminary Conclusions for Non-Interference Analyses for 
North Carolina's Request for Removal of the Federal RVP Requirement

    On April 12, 2013, NC DENR submitted a revision to the maintenance 
plan for the Triad 1-hour ozone maintenance area. The revision updates 
the on-road mobile, non-road mobile, and area source emissions that 
would result from modifying the RVP summertime gasoline requirement 
from 7.8 psi to 9.0 psi for the Triad Area. North Carolina's April 12, 
2013, SIP revision also includes an evaluation of the impact that the 
removal of the 7.8 psi RVP requirement would have on maintenance of the 
1997 and 2008 ozone standards and on other applicable NAAQS. For the 
purposes of this change, EPA is making the preliminary determination 
that the applicable NAAQS \5\ of interest for the non-interference 
demonstration required by section 110(l) of the CAA are the carbon 
monoxide (CO), ozone, particulate matter (PM) and nitrogen dioxide 
(NO2) standards.
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    \5\ The six NAAQS for which EPA establishes health and welfare 
based standards are carbon monoxide, lead, NO2, ozone, 
PM, and SO2.
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    VOC and NOX emissions are precursors for ozone and PM, 
and NO2 is a component of NOX. In addition, EPA 
also believes that, in this instance, it is appropriate to also 
evaluate non-interference with respect to the CO NAAQS. Typically, EPA 
would not expect the CO NAAQS to be affected by a revision to RVP 
requirements because VOC and NOX are not precursors to CO. 
The revised modeling submitted by North Carolina, however, demonstrates 
a slight increase in CO emissions, and as such, EPA believes a non-
interference review for CO is also appropriate in this case.
    There are no emissions reductions attributable to the emissions of 
lead and sulfur dioxide (SO2) from RVP requirements. As a 
result, there is no

[[Page 70520]]

information indicating the proposed revision would have any impact on 
those NAAQS. Additionally, the Triad Area is currently designated 
attainment for the lead NAAQS, and is continuing to attain the 
standard. As for the SO2 NAAQS, the Triad Area is not 
designated nonattainment and there is no available monitoring data 
indicating an exceedance of the NAAQS. Therefore, the analysis below 
focuses on the impact of North Carolina's requested RVP change to the 
ozone, particulate matter, NO2 and CO NAAQS.
    In North Carolina's April 12, 2013, SIP revision, the State 
provided a technical demonstration to support the request to modify the 
RVP summertime gasoline requirement from 7.8 psi to 9.0 psi for the 
Triad Area. NC DENR provided information regarding the emissions trends 
from the maintenance plans for the ozone NAAQS and conducted a 
photochemical modeling exercise to show that modifying the RVP 
summertime gasoline requirement from 7.8 psi to 9.0 psi would have no 
impact on the ozone and PM2.5 NAAQS.\6\
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    \6\ In addition there was not a significant increase in CO and 
NO2 emissions. See the non-interference discussions below 
for more details.
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    In the April 12, 2013, SIP revision, NC DENR provided an updated 
analysis utilizing EPA's MOVES emission modeling system to estimate 
emissions for mobile sources. These mobile source emissions are used as 
part of the evaluation of the potential impacts to the ozone NAAQS that 
might result exclusively from changing the high ozone season RVP 
requirements from 7.8 psi to 9.0 psi. The MOVES data resulted in minor 
increases to the on-road mobile and area source emissions. The State 
then used the MOVES-generated revised mobile source emissions in the 
Triad Area that resulted from the RVP program change in photochemical 
grid modeling to simulate the impact on ozone formation. In addition to 
modeling the small RVP changes over the Triad Area, NC DENR also 
modeled the shutdown of three coal-fired electric generating units 
(EGUs) (Buck, Dan River, and Riverbend), that were located in counties 
adjacent to the Triad Area. Combined-cycle natural gas units have been 
built at two of these facilities (Buck and Dan River) replacing the now 
decommissioned coal-fired units. The federally-enforceable emission 
limits associated with these new combined-cycle units were included 
with the modeling conducted by NC DENR. The modeling shows that 
relaxation of the RVP standard to 9.0 psi would not interfere with 
continued maintenance of the ozone NAAQS in the Triad Area.

b. Non-Interference Analysis for the Ozone NAAQS

    As previously discussed, effective November 6, 1991, the Triad Area 
(which consisted of Davidson, Forsyth and Guilford Counties in their 
entirety and a portion of Davie County) was designated as nonattainment 
for the 1-hour ozone NAAQS. As a 1-hour ozone nonattainment area, 
Davidson, Davie, Forsyth and Guilford Counties were subject to the 
federal RVP requirements for high ozone season gasoline to aid the Area 
with compliance with the ozone NAAQS. On November 13, 1992, NC DENR 
submitted a redesignation request and maintenance plan for the 1-hour 
ozone NAAQS.
    On February 6, 2008, EPA proposed that 13 nonattainment areas with 
deferred effective dates, including the Greensboro-Winston Salem-High 
Point Area, be designated attainment for the 1997 8-hour ozone NAAQS. 
See 73 FR 6863. These areas met all of the milestones of the EAC 
program and demonstrated that they were in attainment of the 1997 8-
hour ozone NAAQS as of December 31, 2007. Effective April 15, 2008, the 
Greensboro-Winston Salem-High Point EAC Area was designated as 
attainment for the 1997 8-hour ozone NAAQS with a design value of 0.083 
ppm using three years of quality assured data for the years of 2005-
2007.
    Throughout this history, there is an overall downward trend in 
ozone concentration in the Triad Area that can be attributed to Federal 
and State programs that have led to significant emissions reductions. 
The Triad Area is continuing to meet the 1-hour and 1997 8-hour ozone 
NAAQS.\7\ With respect to the 2008 ozone NAAQS, based on the 2010-2012 
design values of 0.078 ppm and 0.076 ppm, Triad Area monitors in 
Forsyth and Guilford Counties, respectively, are violating the 2008 
ozone NAAQS. However, the preliminary 2011-2013 design values for 
Forsyth and Guilford Counties are 0.073 ppm and 0.072 ppm, 
respectively.
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    \7\ The air quality design value for the 8-hour ozone NAAQS is 
the 3-year average of the annual 4th highest daily maximum 8-hour 
ozone concentration. The level of the 2008 8-hour ozone NAAQS is 
0.075 ppm. The 2008 8-hour ozone NAAQS is not met when the design 
value is greater than 0.075 ppm.
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    The 2008 ozone NAAQS is met when the annual fourth-highest daily 
maximum 8-hour average concentration, averaged over 3 years is 0.075 
ppm or less. Currently (as shown in Table 1), all ozone monitors in the 
Triad Area are attaining the 1997 8-hour ozone NAAQS, and all but three 
ozone monitors (two located in Forsyth County and one located in 
Guilford County) are attaining the 2008 8-hour ozone NAAQS.

                                                            Table 1--Triad Area Design Value
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           2005-2007 DV    2006-2008 DV    2007-2009 DV    2008-2010 DV    2009-2011 DV    2010-2012 DV
                         County                                (ppm)           (ppm)           (ppm)           (ppm)           (ppm)           (ppm)
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Caswell.................................................           0.077           0.079           0.076           0.073           0.070           0.073
Davie...................................................           0.083           0.082           0.078           (\8\)  ..............           0.073
Forsyth.................................................           0.081           0.081           0.077           0.076           0.075           0.078
Guilford................................................           0.082           0.082           0.079           0.076           0.074           0.076
Rockingham..............................................           0.078           0.080           0.078           0.075           0.071           0.073
--------------------------------------------------------------------------------------------------------------------------------------------------------
------- indicates no data available.

     
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    \8\ The Davie County monitor was moved to a new location and 
began monitoring at the new location in 2008. There was not enough 
data at this location to calculate a 3 year averaged design value 
until 2012.
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    On October 22, 2013, NC DENR submitted a letter to EPA describing 
its intention to early certify ozone monitoring data for the Triad Area 
based on 2011-2013 data. Once certified, this data is expected to 
demonstrate that all monitors in the Triad Area are attaining the 2008 
8-hour ozone NAAQS based on 2011-2013 data. EPA is proposing this 
action contingent on the 2011-2013 monitoring data, showing continued 
attainment of the 2008 ozone NAAQS, being quality assured and certified 
prior

[[Page 70521]]

to the Agency taking final action on this proposed rule.
    The primary precursors for ozone are VOC and NOX 
emissions. Relaxation of the RVP standard from 7.8 to 9.0 psi results 
in a slight increase in emissions of 0.16 tons per day (tpd) (a 0.28 
percent increase) in NOX, and 1.43 tpd (a 1.34 percent 
increase) in VOC for Davidson, Forsyth, Guilford and Davie Counties. 
While modeling showed a slight increase in NOX and VOC 
emissions resulting from the use of 9.0 psi RVP gasoline as opposed to 
7.8 psi RVP gasoline, the most appropriate analysis for purposes of 
evaluating non-interference is whether the increase in emissions would 
interfere with air quality for the Triad Area. For this demonstration, 
NC DENR chose to use photochemical modeling which is described below.
    In addition to analyzing the photochemical modeling provided by 
North Carolina, EPA also notes that the Triad Area is located within a 
NOX-limited region.\9\ A NOX-limited region is 
one in which the concentration of ozone is limited by the amount of 
NOX emissions. As discussed above, NOX and VOC 
are precursors to the formation of ozone in the atmosphere. In a 
NOX-limited area, high prevailing concentrations of VOC from 
naturally-occurring sources are present in the atmosphere to contribute 
to ozone formation. Consequently, reduction of manmade, or 
anthropogenic, sources of VOC emissions generally do not result in 
reduced ozone formation. Instead, reductions of NOX 
emissions provide a more effective ozone reduction strategy because 
reduced emissions of manmade NOX emissions limit the amount 
of NOX available in the atmosphere for ozone formation. 
These circumstances help support the reasonableness of the modeling 
showing that the small increase in VOC and even smaller increase in 
NOX from the relaxation of the RVP standard would not 
interfere with continued maintenance of the ozone NAAQS in the Triad 
Area.
---------------------------------------------------------------------------

    \9\ See, e.g., The State of the Southern Oxidants Study (SOS) 
Policy Relevant Findings in Ozone and PM2.5 Pollution 
Research 1995-2003 (June 30, 2004), http://www.ncsu.edu/sos/pubs/sos3/State_of_SOS_3.pdf.
---------------------------------------------------------------------------

    NC DENR utilized EPA's Mercury and Air Toxics (MATS) modeling 
platform to model changes in ozone and particle matter pollution. The 
modeling years used in the modeling included the 2005 base year and the 
2016 future year. The future year 2016 was chosen because it is the 
latest MATS model data available. The USEPA MATS modeling platform was 
chosen because it is fairly recent, has undergone full model 
performance, and uses the MOVES mobile model to generate on-road mobile 
emissions. The USEPA MATS modeling used a national 36 kilometer (km) 
domain and an eastern US 12 km domain. The NC DENR modeling was 
performed using the 12 km modeling domain. The EPA is currently using 
12 km modeling to address the impacts of the proposed Tier 3 Motor 
Vehicle and Emissions Standards. Given that the EPA is using the 12 km 
modeling for Tier 3, NC DENR used the 12 km modeling to estimate the 
impacts of the change in summertime RVP to 9.0 psi.
    The USEPA MATS modeling conducted by NC DENR demonstrates that the 
relaxation of the RVP 7.8 standard to 9.0 psi in the Triad 1-hour ozone 
maintenance area is not necessary to maintain the either the 1997 or 
2008 ozone NAAQS. Both the 2005 base year and the 2016 future year were 
used in the modeling. In the modeling NC DENR applied several 
conservative estimates to determine the maximum impact of RVP 
relaxation. These included:
    (1) Selecting the most populous county to represent on-road mobile 
emissions for the other counties. Guilford County was selected to 
represent the ``highest'' level of emissions increase expected because 
it has the greatest population of vehicles and vehicle miles traveled 
(VMT) within the Triad maintenance area.
    (2) Applying the maximum emissions increase for a given hour to the 
entire summertime period. Typically, the next step is to run SMOKE \10\ 
to temporally and spatially allocate the MOVES output. However, NC DENR 
was unable to run the version of SMOKE used in the MATS modeling. As an 
alternative, for each pollutant, the average and maximum increase at 
any hour was calculated (see Table 2.3-8 of the NC submittal). In order 
to generate very conservative estimates of the impacts of the RVP 
relaxation, the maximum percent increase was applied to the mobile 
emissions for all hours of the June 1 to September 15 high-ozone season 
RVP period for both the 2005 and 2016 emissions in Guilford, Forsyth, 
Davie, and Davidson Counties where the RVP relaxation is proposed.
---------------------------------------------------------------------------

    \10\ SMOKE, or ``Sparse Matrix Operator Kernel Emissions'' is an 
emissions processing system designed to create gridded, speciated, 
hourly emissions for input into a variety of air quality models. 
SMOKE supports area, biogenic, mobile (both onroad and nonroad), and 
point source emissions processing for criteria, particulate, and 
toxic pollutants and is integrated with the on-road emissions model 
MOBILE6 and MOVES.
---------------------------------------------------------------------------

    (3) Using the highest emissions increase for a given pollutant to 
represent VOC emissions.
    (4) The liberal application of grid masking (i.e., the array of 
grid cells where the RVP emissions changes were applied). A grid cell 
was included in the grid cell mask if as little as 20 percent of the 
cell area includes one or more of the counties where the RVP relaxation 
is proposed. The grid cell mask includes 42 grid cells with an area of 
6,048 km\2\. A typical application of the mask would include 32 grid 
cells with an area of 4,608 km\2\. By comparison, the total area of the 
four counties is 4,935 km\2\. The 20 percent threshold grid cell mask 
used in the modeling will adjust the mobile emissions in a larger area 
than the actual area of the four counties and will lead to conservative 
modeling results.
    NC DENR used the Community Multiscale Air Quality Modeling System 
(CMAQ, v.4.71) to perform the air quality runs. A total of six runs 
were made from March 20, 2005 to September 30, 2005. A total of three 
runs were made using the 2005 emissions. The first run used the default 
2005 MATS emissions (BASE05). The second run adjusted the mobile 
emissions due to the change in RVP from 7.8 psi to 9.0 psi during the 
June 1 to September 15 RVP period (RVP05). The third run for 2005 
included the RVP adjustments and added expected NOX changes 
at the Buck, Dan River, Riverbend power plants. The 2016 model runs 
were run in a similar fashion as the 2005 runs. The first run used the 
default 2016 MATS emissions (BASE16). The second run adjusted the 
mobile emissions due to the change in RVP from 7.8 to 9.0 psi during 
the June 1 to September 15 RVP period (RVP16) and the third included 
the RVP adjustments and added expected NOX changes at the 
Buck, Dan River, Riverbend power plants.
    In this application, The Model Attainment Test Software was used to 
compute relative reduction factors (RRFs) for each of the sensitivity 
runs at the area monitors. The 2005 sensitivity runs were compared to 
the Base05 run, and the 2016 sensitivity runs were compared to the 
Base16 run. RRF values of 1.0005 or less would indicate less than a 
0.05 ppb rise within the base year or future year modeling. The change 
in ozone for monitors in and near the Triad Area generated by the 
change in RVP in the 2005 base year is shown in Table 2. The other runs 
had similar results. There is no appreciable change in ozone 
concentrations due to the increase in gasoline RVP.
    See North Carolina's April 12, 2013, submittal for more information 
on the modeling demonstration.

[[Page 70522]]

  Table 2--Change in Ozone Concentrations and RRFs in the 2005 Base Year Modeling With Summertime RVP Change to
                                                     9.0 psi
----------------------------------------------------------------------------------------------------------------
                                                   County Base05
                                                   ozone design     RVP05 Ozone                     Change from
                     County                          value \1\     design value         RRF          Base05 to
                                                       (ppb)         \2\ (ppb)                     RVP05  (ppb)
----------------------------------------------------------------------------------------------------------------
Caswell.........................................            76.3            76.3          1.0002             0.0
Davie...........................................            81.3            81.3          1.0002             0.0
Forsyth.........................................            78.0            78.0          1.0004             0.0
Forsyth.........................................            73.0            73.0          1.0003             0.0
Forsyth.........................................            76.0            76.0          1.0004             0.0
Forsyth.........................................            80.0            80.0          1.0004             0.0
Guilford........................................            77.0            77.0          1.0005             0.0
Guilford........................................            82.0            82.0          1.0005             0.0
Rockingham......................................            77.0            77.0          1.0003             0.0
----------------------------------------------------------------------------------------------------------------
\1\ Default 2005 MATS concentrations.
\2\ 2005 concentrations with summertime RVP changed to 9.0 psi.

It should also be noted that in its submission, North Carolina provided 
a demonstration that there is no appreciable change in future ozone 
design value concentrations at any of the area monitors when comparing 
changes in ozone concentration and RRFs in a future year scenario for 
2016 that modeled summertime RVP at 9.0 psi. North Carolina's model 
runs were done solely for the purpose of determining potential and 
relative impact for changes in ozone concentration due to a change of 
RVP to 9.0 psi. More information on the MATS modeling can be found at 
http://www.epa.gov/mats/actions.html. Additional details on NC DENR's 
updates to the EPA MATS modeling platform to incorporate emissions in 
North Carolina are included in the State's April 12, 2013, SIP 
revision.

    To provide a full evaluation, the State also compared total man-
made (anthropogenic) emissions of VOC and NOX for the years 
2007 (base year), 2011, and 2018 using a RVP of 7.8 psi for Davidson, 
Forsyth, Guilford and Davie Counties (the remaining Counties are 
currently using a RVP of 9.0 psi) to emissions generated for the year 
2018, using a RVP of 9.0 psi.
    There are four different man-made emission inventory source 
classifications: (1) Point, (2) area, (3) on-road mobile and (4) non-
road mobile.
    (1) Point sources are those stationary sources that emit more than 
10 tons per year of VOC or 100 tons per year of NOZX from a 
single facility. The source emissions are tabulated from data collected 
by direct on-site measurements of emissions or mass balance 
calculations utilizing emission factors from EPA's AP-42, Compilation 
of Air Pollutant Emission Factors. For the projected year's inventory, 
point sources are adjusted by growth factors based on Standard 
Industrial Classification codes. The growth factors are generated using 
the EPA's Economic Growth Analysis System version 5.0 (E-GAS 5.0) 
program.
    (2) Area sources are those stationary sources whose emissions are 
relatively small but due to the large number of these sources, the 
collective emissions could be significant (i.e., dry cleaners, service 
stations, etc.). For area sources, emissions are estimated by 
multiplying an emission factor by some known indicator of collective 
activity such as production, number of employees, or population. These 
types of emissions are estimated on the county level. For the projected 
year's inventory, area source emissions are changed by population 
growth, projected production growth, or when applicable, by E-GAS 5.0 
growth factors.
    (3) On-road mobile sources are those vehicles that travel on the 
roadways. For on-road mobile sources, the MOVES model data represent 
the new motor vehicle emission budgets for the Triad Area. The MOVES 
model uses the road class VMT and other operating conditions as input 
parameters to generate an output file that contains estimated 
emissions. For the projected years inventories, the on-road mobile 
sources emissions are calculated by running the MOVES mobile model for 
the future year with the projected VMT to generate emissions that take 
into consideration expected Federal tailpipe standards, fleet turnover 
and new fuel standards.
    (4) Non-road mobile sources are equipment that can move but do not 
use the roadways (i.e., lawn mowers, construction equipment, railroad 
locomotives, aircraft). With the exception of the railroad locomotives 
and aircraft engines, the emissions from this category are calculated 
using the EPA's NONROAD2008a non-road mobile model. The railroad 
locomotive and aircraft engine emissions are estimated by taking an 
activity and multiply by an emission factor. All emissions are also 
estimated at the county level. Total off-road mobile source emissions 
represent the sum of emissions generated by the NONROAD 2008a model and 
emissions calculated for aircraft and railroad locomotives.
    Despite the small increases in emissions projected for the less-
stringent RVP standard of 9.0 psi, the Triad Area continues to 
demonstrate a downward trend in NOX and VOC emissions 
through 2018. Tables 3 and 4 below provide the emissions inventory 
estimates for all source categories for the 1-hour ozone maintenance 
area.

                Table 3--Anthropogenic VOC Emissions (tpd) for the Triad 1-Hour Maintenance Area
----------------------------------------------------------------------------------------------------------------
                                                                Based on RVP of 7.8                Based on RVP
                                                 ------------------------------------------------     of 9.0
                     County                                                                      ---------------
                                                       2007            2011            2018            2018
----------------------------------------------------------------------------------------------------------------
Davidson........................................           19.31           17.60           14.29           14.50
Davie *.........................................            8.04            7.79            8.43            8.43
Forsyth.........................................           36.62           32.63           32.69           33.18

[[Page 70523]]

 
Guilford........................................           58.31           53.71           51.10           51.83
                                                 ---------------------------------------------------------------
    Total.......................................          122.28          111.73          106.51          107.94
----------------------------------------------------------------------------------------------------------------
* Emissions are for the entire County.

                Table 4--Anthropogenic NOX Emissions (tpd) for the Triad 1-Hour Maintenance Area
----------------------------------------------------------------------------------------------------------------
                                                                Based on RVP of 7.8                Based on RVP
                                                 ------------------------------------------------     of 9.0
                     County                                                                      ---------------
                                                       2007            2011            2018            2018
----------------------------------------------------------------------------------------------------------------
Davidson........................................           21.99           17.94            9.88            9.91
Davie *.........................................            6.08            4.41            2.75            2.75
Forsyth.........................................           35.88           24.47           16.50           16.54
Guilford........................................           57.68           44.76           28.00           28.09
                                                 ---------------------------------------------------------------
    Total.......................................          121.63           91.58           57.13           57.29
----------------------------------------------------------------------------------------------------------------
* Emissions are for the entire County.

    As Tables 3 and 4 indicate, NOX and VOC emissions in the 
Triad 1-hour ozone maintenance area will continue to decrease, even 
with the increase in high ozone season fuel RVP to 9.0 psi. The slight 
increase in emissions resulting from the control program change is 
being mitigated area-wide by a steady decrease in tailpipe emissions, 
which is the result of a cleaner new vehicle fleet replacing the older 
fleet and other Federal and State emissions reduction programs.
    In light of the current designations, monitoring and emissions 
data, and the submitted modeling, including the fact that the 
NOX emissions inventories are projected to continue to 
significantly decrease, EPA has preliminarily determined that the 
slight increase in NOX and VOC emissions associated with the 
request RVP change will not interfere with the Area's ability to 
maintain the 1997 and 2008 8-hour ozone NAAQS. More details on the 
individual non-interference analyses for the PM2.5, 
NO2 and CO NAAQS are provided below.

c. Non-Interference Analysis for the PM NAAQS

    The precursors for PM2.5 are NOX, 
SO2, VOC and ammonia. For the Triad Area, on-road mobile, 
non-road mobile and area sources are not considered to be large 
contributors to directly emitted PM2.5 or indirectly formed 
fine particulate matter less than 2.5 micrometers (PM2.5) 
concentrations. As mentioned earlier in this rulemaking, the RVP 
requirements result in emissions benefits for VOC and NOX, 
and as such EPA focused on these precursors for the analysis of the 
potential impact of North Carolina's SIP change. However, as described 
in North Carolina's April 12, 2013, submission, directly emitted 
PM2.5 is a very small component of the overall 
PM2.5 ambient concentrations. Instead the primary species 
impacting PM2.5 concentrations are the secondarily formed 
sulfates and organic carbons. Sulfates are formed through the chemical 
reaction of SO2 and ammonia and the majority of the organic 
carbons come from natural sources like trees. See ``Redesignation 
Demonstration and Maintenance Plan for the Hickory (Catawba County) and 
Greensboro/Winston-Salem/High Point (Davidson and Guilford Counties) 
Fine Particulate Matter Nonattainment Areas,'' submitted to EPA on 
December 18, 2009, Figure 4-2, p. 4-4, which can be accessed at 
www.regulations.gov using docket ID No. EPA-R04-OAR-2009-1010. A 2009 
analysis of SO2 emissions, which is a primary contributor to 
the formation of PM2.5 within North Carolina, found about 
3.3 percent of total SO2 emissions came from on-road, non-
road and area sources combined, while the remaining 96.7 percent came 
from point sources.
    On July 18, 1997 (62 FR 36852), EPA established an annual 
PM2.5 NAAQS at 15.0 micrograms per cubic meter ([mu]g/m\3\) 
based on a 3-year average of annual mean PM2.5 
concentrations. At that time, EPA also established a 24-hour NAAQS of 
65 [mu]g/m\3\. See 40 CFR 50.7. On October 17, 2006 (71 FR 61144), EPA 
retained the 1997 annual PM2.5 NAAQS at 15.0 [mu]g/m\3\ 
based on a 3-year average of annual mean PM2.5 
concentrations, and promulgated a new 24-hour NAAQS of 35 [mu]g/m\3\ 
based on a 3-year average of the 98th percentile of 24-hour 
concentrations. On January 15, 2013 (78 FR 3086), EPA established an 
annual primary PM2.5 NAAQS at 12.0 [mu]g/m\3\ based on a 3-
year average of annual mean PM2.5 concentrations. At that 
time, EPA retained the 2006 24-hour NAAQS at 35 [mu]g/m\3\ based on a 
3-year average of the 98th percentile of 24-hour concentrations.
    On January 5, 2005 (70 FR 944), Davidson and Guilford Counties in 
the Triad Area were designated nonattainment for the 1997 annual 
PM2.5 standard and all other Counties were designated 
Unclassifiable/Attainment. On November 13, 2009 (74 FR 58688), all 
counties in the Triad Area were designated unclassifiable/attainment 
for the 2006 24-hour PM2.5 standard. On November 18, 2011, 
EPA redesignated Davidson and Guilford Counties to attainment for the 
1997 annual PM2.5 standard based on the measured air quality 
data and the 10-year maintenance plan submitted. See 76 FR 71455.
    As Table 5 indicates the PM2.5 annual and 24-hour design 
values demonstrate attainment of the respective NAAQS and have been 
decreasing.

[[Page 70524]]

                                          Table 5--PM2.5 Design Values
----------------------------------------------------------------------------------------------------------------
                              Year                                   2008-2010       2009-2011       2010-2012
----------------------------------------------------------------------------------------------------------------
                                               Annual Design Value
----------------------------------------------------------------------------------------------------------------
Caswell.........................................................             9.9             8.9             8.9
Davidson........................................................            12.1            11.1            11.1
Forsyth.........................................................            10.9            10.0             9.7
Guilford........................................................            10.8             9.8             9.4
----------------------------------------------------------------------------------------------------------------
                                              24-hour Design Value
----------------------------------------------------------------------------------------------------------------
Caswell.........................................................              19              18              18
Davidson........................................................              23              21              21
Forsyth.........................................................              23              21              20
Guilford........................................................              22              21              21
----------------------------------------------------------------------------------------------------------------
EPA Annual PM2.5 NAAQS: 15 [mu]g/m\3\.
EPA 24-hour PM2.5 NAAQS: 35 [mu]g/m\3\.

    In light of the slight increase in VOC and NOX emissions 
from the relaxation of the RVP controls in Davidson, Davie, Forsyth and 
Guilford Counties, EPA has preliminarily determined that a change to 
the Federal RVP requirement for Davidson, Davie, Forsyth and Guilford 
Counties would not interfere with the Triad Area maintaining the 1997 
PM2.5 annual or the 2006 24-hour PM2.5 standards. 
The photochemical modeling analysis discussed above was also used to 
calculate the changes in PM2.5 due to the RVP Program 
change. The analysis showed no change in particle pollution at any of 
the monitors.

d. Non-Interference Analysis for the 2010 NO2 NAAQS

    On February 17, 2012 (77 FR 9532), EPA finalized designations for 
2010 NO2 NAAQS. Counties in North Carolina, including those 
in the Triad Area, were designated unclassifiable/attainment for the 
2010 NO2 NAAQS. Based on North Carolina's April 12, 2013, 
SIP revision, the potential increase in the NOX emissions 
associated with the requested less-stringent RVP standard is 
approximately a quarter of a ton per day between June 1st and September 
15th. It is reasonable to believe that North Carolina's requested 
change for its high ozone season RVP requirement would not cause the 
Area to be out of compliance with the 2010 NO2 NAAQS because 
the slight projected NOX emissions increase would be 
mitigated by a steady decrease in tailpipe emissions, which is the 
result of cleaner new vehicle fleet replacing the older fleet. In light 
of the current designation, monitoring and emissions trend data and the 
submitted modeling, including the fact that NOX emissions 
inventories are projected to continue to significantly decrease,\11\ 
EPA has preliminarily determined that a change to the Federal RVP 
requirements for the Triad Area would not interfere with the continued 
decline in NOX emissions, nor with attainment or maintenance 
of the 2010 NO2 NAAQS.
---------------------------------------------------------------------------

    \11\ See table 5, above.
---------------------------------------------------------------------------

e. Non-Interference Analysis for the CO NAAQS

    Forsyth County in the Triad Area was previously designated 
nonattainment for the 8-hour CO NAAQS. See 56 FR 56694, November 6, 
1991. Subsequently, Forsyth County attained the 8-hour CO NAAQS and was 
redesignated from nonattainment to attainment on September 21, 1994, 
based on the measured air quality data and the 10-year maintenance plan 
submitted. See 59 FR 48399. The 8-hour CO NAAQS is 9 ppm and the 1-hour 
CO NAAQS is 35 ppm. As provided in Table 6 below, monitoring data from 
2008-2011 shows Forsyth County is well below the 8-hour and 1-hour CO 
NAAQS.

                      Table 6--Ambient Air Quality CO 8-Hour and 1-Hour Design Values (ppm)
----------------------------------------------------------------------------------------------------------------
             County                 Monitor ID         2009            2010            2011            2012
----------------------------------------------------------------------------------------------------------------
                                                   8-hr NAAQS
----------------------------------------------------------------------------------------------------------------
Forsyth.........................       370670023             1.7             1.9             2.1             1.2
----------------------------------------------------------------------------------------------------------------
                                                   1-hr NAAQS
----------------------------------------------------------------------------------------------------------------
Forsyth.........................       370670023             2.3             2.7             2.6             1.8
----------------------------------------------------------------------------------------------------------------

    It is estimated that Triad Area on-road CO emissions will increase 
approximately 5 tons per day in 2016 if the applicable RVP requirement 
is relaxed to 9.0 psi in the Triad Area. This increase equates to a 
less than a 1.0 percent increase in the total inventory of all 
anthropogenic sources for the Triad Area. In light of the slight 
increase in CO emissions EPA has preliminarily determined that a change 
to the Federal RVP requirement for Greensboro/Winston-Salem/High Point 
would not interfere with the Winston-Salem/Forsyth County Area 
maintaining the CO NAAQS.

VI. Proposed Action

    EPA is proposing to approve the State of North Carolina's April 12, 
2013, revision to its 110(a)(1) Maintenance Plan for the Triad 1997 8-
hour Ozone Maintenance Area. Specifically, EPA is proposing to approve 
the State's showing that the Triad Area can continue to maintain the 
1997 ozone

[[Page 70525]]

standard without emissions reductions associated with the use of 
gasoline with an RVP of 7.8 psi in the four Triad Area counties during 
the high ozone season--June 1 through September 15.
    In addition, due to the updated modeling reflecting a change in the 
applicable RVP standard, the North Carolina revision also includes an 
updated on-road mobile, non-road mobile and area source emissions for 
the Triad Area. EPA is also proposing approval of this revision.
    EPA has preliminarily determined that North Carolina's April 12, 
2013, SIP revision, including the technical demonstration associated 
with the State's request for the removal of the Federal RVP 
requirements, and the updated on-road mobile, non-road mobile and area 
source emissions are consistent with the applicable provisions of the 
CAA. Should EPA decide to remove subject portions of the Triad Area 
from those areas subject to the 7.8 psi Federal RVP requirements, such 
action will occur in a separate, subsequent rulemaking.

VII. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submittal that complies with the provisions of the Act and applicable 
federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve state choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
proposed action merely approves state law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Order 
12866 (58 FR 51735, October 4, 1993);
     does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, October 7, 1999);
     is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA; and
     does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this proposed rule does not have tribal implications 
as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), 
because the SIP is not approved to apply in Indian country located in 
the state, and EPA notes that it will not impose substantial direct 
costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Intergovernmental 
relations, Lead, Reporting and recordkeeping requirements.

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

    Dated: November 12, 2013.
Beverly H. Banister,
Acting Regional Administrator, Region 4.
[FR Doc. 2013-28371 Filed 11-25-13; 8:45 am]
BILLING CODE 6560-50-P