Proposed Rule2026-09146
Air Plan Approval; NC; Removal of the State's Vehicle Inspection and Maintenance Program
Primary source
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Published
May 8, 2026
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to approve a State Implementation Plan (SIP) revision submitted by the State of North Carolina, through the North Carolina Division of Air Quality (NCDAQ), on October 1, 2024. The revision seeks to remove North Carolina's vehicle inspection and maintenance (I/M) program from North Carolina's SIP which covers 19 counties. EPA is proposing to approve this change as it will not interfere with any applicable requirement concerning attainment and reasonable further progress or any other applicable requirement of the Clean Air Act (CAA or Act).
Full Text
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<title>Federal Register, Volume 91 Issue 89 (Friday, May 8, 2026)</title>
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[Federal Register Volume 91, Number 89 (Friday, May 8, 2026)]
[Proposed Rules]
[Pages 25257-25266]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-09146]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R04-OAR-2025-0305; FRL-13350-01-R4]
Air Plan Approval; NC; Removal of the State's Vehicle Inspection
and Maintenance Program
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve a State Implementation Plan (SIP) revision submitted by the
State of North Carolina, through the North Carolina Division of Air
Quality (NCDAQ), on October 1, 2024. The revision seeks to remove North
Carolina's vehicle inspection and maintenance (I/M) program from North
Carolina's SIP which covers 19 counties. EPA is proposing to approve
this change as it will not interfere with any applicable requirement
concerning attainment and reasonable further progress or any other
applicable requirement of the Clean Air Act (CAA or Act).
DATES: Comments must be received on or before June 8, 2026.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2025-0305 at <a href="http://regulations.gov">regulations.gov</a>. Follow the online instructions for
submitting comments. Once submitted, comments cannot be edited or
removed from Regulations.gov. EPA may publish any comment received to
its public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
FOR FURTHER INFORMATION CONTACT: Weston Freund, Air Regulatory
Management Section, Air Planning and Implementation Branch, Air and
Radiation Division, U.S. Environmental Protection Agency, Region 4, 61
Forsyth Street SW, Atlanta, Georgia 30303-8960. The telephone number is
(404) 562-8773. Mr. Freund can also be reached via electronic mail at
<a href="/cdn-cgi/l/email-protection#88eefaedfde6eca6ffedfbfce7e6c8edf8e9a6efe7fe"><span class="__cf_email__" data-cfemail="f4928691819a90da839187809b9ab4918495da939b82">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
I. What is being proposed?
North Carolina submitted a SIP revision on October 1, 2024, seeking
to remove its SIP-approved I/M program, which covers the following
counties: Alamance, Buncombe, Cabarrus, Cumberland, Davidson, Durham,
Forsyth, Franklin, Gaston, Guilford, Iredell, Johnston, Lincoln,
Mecklenburg, New Hanover, Randolph, Rowan, Union, and Wake. The SIP-
approved I/M program consists of the following rules under 15A NCAC
02D, Section .1000 Motor Vehicle Emission Control Standards: Rule
.1001, Purpose; Rule .1002, Applicability; Rule .1003, Definitions; and
Rule .1005, On-Board Diagnostic Standards. NCDAQ submitted this SIP
revision in response to North Carolina Session Law (S.L.) 2023-134
(House Bill 259), which amended North Carolina General Statute (NCGS)
section 143-215.107A(c).\1\
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\1\ Section 12.7(b) of S.L. 2023-134 amended NCGS section 143-
215.107A(c) to remove 18 of the 19 counties from North Carolina's I/
M program, and Section 12.7(a) amended NCGS section 20-183.2(b) to
change the vehicle model year coverage for Mecklenburg County which
is the only county that would be retained in the state-level
program. Section 12.7(d) of S.L. 2023-134 requires that Sections
12.7(a) and (b) become effective on the first day of a month that is
60 days after the Secretary of the Division of Environmental Quality
certifies to the Revisor of Statutes that EPA has approved an
amendment to the North Carolina SIP submitted as required by Section
12.7(c) (i.e., the October 1, 2024 SIP revision) and applies to
motor vehicles inspected, or due to be inspected, on or after that
date.
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Sections 182(b)(4) and 187(a)(4) of the CAA require the
implementation of an I/M program in certain areas classified as
Moderate nonattainment or higher for the ozone or carbon monoxide (CO)
National Ambient Air Quality Standards (NAAQS). In addition to the
counties that were required to implement I/M in North Carolina by the
CAA, North Carolina opted to expand the I/M program to comply with a
rule entitled ``Finding of Significant Contribution and Rulemaking for
Certain States in the Ozone Transport Assessment Group Region for
Purposes of Reducing Regional Transport of Ozone'' (also referred to as
the NO<INF>X</INF> SIP Call).\2\ The I/M program was expanded in 2002
to include 39 total counties, including those covered in this proposed
action, to provide North Carolina with emissions credits to meet its
NO<INF>X</INF> SIP Call obligations. See 67 FR 66056 (October 30,
2002). The NO<INF>X</INF> SIP Call, issued by EPA in 1998, required
some states, including North Carolina, to meet statewide NO<INF>X</INF>
emission requirements during the ozone season (May 1 through September
30 control period) to reduce the amount of ground level ozone that is
transported across the eastern United States. See 84 FR 8422 (March 8,
2019). All counties in North Carolina are currently designated as
attainment for all NAAQS.
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\2\ See 63 FR 57356 (October 27, 1998).
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As a part of the State's October 1, 2024, submittal, North Carolina
included a CAA section 110(l) non-interference demonstration. Under
section 110(l) of the CAA, EPA cannot approve a SIP revision if it
would interfere with any applicable requirement concerning attainment
and reasonable further progress (as defined by section 171 of the CAA),
or any other applicable requirement of the CAA. Section III, below,
provides EPA's analysis of the non-interference demonstration.
EPA is proposing to find that removal of North Carolina's I/M
program from the SIP for the remaining 19 counties would not interfere
with North Carolina's obligations under the NO<INF>X</INF> SIP Call.
This proposed finding is based on several federal rules and SIP-
approved State provisions promulgated and implemented after EPA's 2002
approval of North Carolina's NO<INF>X</INF> SIP Call submission. These
federal rules and SIP provisions have created significant
NO<INF>X</INF> emission reductions in North Carolina such that the
credits gained by the 19 counties' participation in the I/M program are
no longer needed for North Carolina to meet its NO<INF>X</INF> SIP Call
Statewide NO<INF>X</INF> emissions budget. North Carolina has provided
an analysis which supports this proposed finding and is discussed in
Sections II.B and III.A of this notice of proposed rulemaking (NPRM).
North Carolina's SIP revision also evaluates the impact that the
removal of the I/M program would have on the
[[Page 25258]]
State's ability to attain and maintain the NAAQS. The SIP revision
contains a technical demonstration with revised emissions calculations
showing that removing the I/M program from the SIP would not interfere
with attainment or maintenance of any NAAQS or any other applicable
requirement of the CAA. As discussed more fully in Section III of this
NPRM, EPA is proposing to find that North Carolina's emissions
calculations demonstrate that removing the I/M program from the SIP
would not interfere with the State's ability to attain or maintain any
NAAQS.
II. Background
A. History of North Carolina's I/M Program
North Carolina's I/M program began in 1982 in Mecklenburg County
utilizing a ``tailpipe'' emissions test. In 1984, Wake County was first
added to the program for CO NAAQS violations. From 1986 through 1991
the program expanded to include Cabarrus, Davidson, Durham, Forsyth,
Gaston, Guilford, and Union Counties, to address violations of the
ozone and/or CO NAAQS. The I/M program was also implemented in Orange
County although it was not designated as nonattainment for the ozone or
CO NAAQS.
In 1999, the North Carolina General Assembly passed legislation
(Session law 1999-328) to expand the coverage area for the I/M program
to gain additional emission reduction credits for its NO<INF>X</INF>
SIP call obligations as well as to achieve the 1997 8-hour ozone NAAQS
in the State. This legislation expanded the I/M program to add 38
counties between July 1, 2003, and July 1, 2006, for a total of 48
counties.\3\ The I/M program in the expanded coverage area used on-
board diagnostic (OBD) system checks rather than tailpipe testing.
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\3\ The 38 counties added during this time period were Alamance,
Buncombe, Brunswick, Burke, Caldwell, Carteret, Catawba, Chatham,
Cleveland, Craven, Cumberland, Edgecombe, Franklin, Granville,
Harnett, Haywood, Henderson, Iredell, Lee, Lenoir, Lincoln,
Johnston, Moore, Nash, New Hanover, Onslow, Pitt, Randolph,
Robertson, Rockingham, Rowan, Rutherford, Stanly, Stokes, Surry,
Wayne, Wilkes, and Wilson.
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On August 7, 2002, North Carolina submitted a SIP revision to amend
the I/M regulations included in the SIP at that time to, among other
things, expand the counties subject to the I/M program as discussed
above, and to require OBD testing in the subject counties for all light
duty gasoline vehicles with a model year (MY) of 1996 and newer.
Additionally, the SIP revision proposed to terminate the tailpipe
testing program on January 1, 2006, for the nine counties subject to
continued tailpipe testing with a MY 1995 and older vehicles. EPA
approved this SIP revision on October 30, 2002. See 67 FR 66056.
On January 31, 2008, May 24, 2010, October 11, 2013, and February
11, 2014, North Carolina submitted SIP revisions to change the I/M
program to exempt the three newest MY vehicles with less than 70,000
miles among other changes. EPA approved these SIP revisions on February
5, 2015. See 80 FR 6455.
On November 17, 2017, North Carolina submitted a SIP revision to
remove 26 counties from the I/M program. EPA approved this SIP revision
on September 25, 2018. See 83 FR 48383.
On July 25, 2018, North Carolina submitted a SIP revision to revise
the MY coverage for the then remaining 22 counties subject to the I/M
program. EPA approved this SIP revision on September 11, 2019. See 84
FR 47889.
On December 14, 2020, North Carolina submitted a SIP revision to
remove three additional counties from the I/M program (Lee, Onslow, and
Rockingham Counties). EPA approved this SIP revision on August 11,
2022. See 87 FR 49524.
The remaining 19 counties in North Carolina's SIP-approved I/M
program are Alamance, Buncombe, Cabarrus, Cumberland, Davidson, Durham,
Franklin, Forsyth, Gaston, Guilford, Johnston, Iredell, Lincoln,
Mecklenburg, New Hanover, Randolph, Rowan, Union, and Wake.
B. NO<INF>X</INF> SIP Call
On August 7, 2002, North Carolina submitted a SIP revision to EPA
as a component of its response to the NO<INF>X</INF> SIP Call
requirements. The NO<INF>X</INF> SIP Call required some states to meet
statewide NO<INF>X</INF> emission requirements during the ozone season
to reduce the amount of ground level ozone transported across the
eastern United States. See 84 FR 8422 (March 8, 2019). As noted above,
North Carolina's SIP revision expanded the I/M program from 10 counties
to 48, pursuant to North Carolina Session Law 1999-328, Section 3.1(d),
and incorporated the OBD test procedure.
The addition of 38 counties to the I/M program pursuant to Section
3.1(d) of the 1999 Session Law and the new OBD testing procedure were
included in the SIP to support the establishment of emission credits
for North Carolina's NO<INF>X</INF> budget and trading program. See 67
FR 66056 (October 30, 2002). EPA approved the I/M rule revision and
North Carolina's use of the I/M program credits for the NO<INF>X</INF>
SIP Call budget and trading program. See 67 FR 66056 (October 30,
2002).
After the NO<INF>X</INF> SIP Call, several federal rules, as well
as North Carolina SIP provisions, have created significant
NO<INF>X</INF> emission reductions in North Carolina, including ozone
season reductions. Consequently, the State asserts that any emissions
reduction credits derived from the 19 counties' participation in the
expanded I/M program are no longer needed for North Carolina to meet
its Statewide NO<INF>X</INF> emissions budget obligations under the
NO<INF>X</INF> SIP Call.
Other large reductions in NO<INF>X</INF> emissions over time have
occurred from federal rules such as the Tier 2 vehicle and fuel
standards; \4\ nonroad spark ignition engines and recreational engine
standards; heavy-duty gasoline and diesel highway vehicle standards;
\5\ and large nonroad diesel engine standards.\6\ These mobile source
measures, coupled with fleet turnover (i.e., the replacement over time
of older vehicles that predate the standards with newer vehicles that
meet the standards), have resulted in, and continue to result in, large
reductions in NO<INF>X</INF> emissions over time.
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\4\ The Tier 2 standards, begun in 2004, continue to
significantly reduce NO<INF>X</INF> emissions, and EPA expects that
these standards will reduce NO<INF>X</INF> emissions from vehicles
by approximately 74 percent by 2030 (or nearly 3 million tons
annually by 2030). See 80 FR 44873 (July 28, 2015) (citing EPA,
Regulatory Announcement, EPA 420-F-99-051 (December 1999).
\5\ Also begun in 2004, implementation of this rule is expected
to achieve a 95 percent reduction in NO<INF>X</INF> emissions from
diesel trucks and buses by 2030. See 80 FR 44873 (July 28, 2015).
\6\ EPA estimated that compliance with this rule will cut
NO<INF>X</INF> emissions from non-road diesel engines by up to 90
percent nationwide. See 80 FR 44873 (July 28, 2015).
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In 2002, North Carolina also enacted and subsequently implemented
its Clean Smokestacks Act (CSA), which created system-wide annual
emissions caps on actual emissions of NO<INF>X</INF> and sulfur dioxide
(SO<INF>2</INF>) from coal-fired power plants within the State, the
first of which became effective in 2007. The CSA required certain coal-
fired power plants in North Carolina to significantly reduce annual
NO<INF>X</INF> emissions by 189,000 tons (or 77 percent) by 2009 (using
a 1998 baseline year). This represented about a one-third reduction of
the NO<INF>X</INF> emissions from all sources in North Carolina. See 76
FR 36468 (June 11, 2011). The CSA's requirement to meet annual
emissions caps and disallow the purchase of NO<INF>X</INF> credits to
meet the caps led to a reduction of NO<INF>X</INF> emissions beyond the
requirements of the NO<INF>X</INF> SIP Call even though the CSA did not
limit emissions only during the ozone season. EPA approved the CSA
emissions caps into North Carolina's SIP
[[Page 25259]]
on September 26, 2011. See 76 FR 59250.
North Carolina also has other SIP-approved provisions that have
helped significantly reduce NO<INF>X</INF> emissions in North Carolina.
Most of these rules are contained in 15A North Carolina Administrative
Code (NCAC) Subchapter 02D, Section .1400, Nitrogen Oxides. These rules
contain NO<INF>X</INF> SIP Call requirements and work in conjunction
with the CSA to reduce NO<INF>X</INF> emissions in the State. Together,
implementation of the federal rules discussed above and SIP-approved
State provisions have created significant NO<INF>X</INF> emissions
reductions since North Carolina's NO<INF>X</INF> SIP Call emissions
budget was approved into the SIP in 2002. These federal rules and SIP-
approved State provisions have significantly reduced ozone season
NO<INF>X</INF> emissions, from Electric Generating Units (EGUs) in
particular, resulting in overall emissions levels well below the
original NO<INF>X</INF> SIP Call budget. North Carolina asserts in its
October 1, 2024, SIP revision that the State can adequately implement
the NO<INF>X</INF> SIP Call with the modeled increases in
NO<INF>X</INF> emissions resulting from removal of the I/M program and
that the resulting NO<INF>X</INF> emissions do not approach the
applicable NO<INF>X</INF> budget in the State. See Section III.A of
this NPRM for additional discussion.
C. I/M in the North Carolina Portion of the Charlotte-Rock Hill, NC-SC
2008 Maintenance Area
The North Carolina portion of the Charlotte-Rock Hill, NC-SC Area
(bi-state Charlotte Area) for the 2008 Ozone NAAQS contains Cabarrus,
Gaston, Iredell, Lincoln, Mecklenburg, Rowan, and Union Counties. The
I/M program is currently identified as a permanent and enforceable
measure in the maintenance plan for the North Carolina portion of the
Charlotte-Rock Hill, NC-SC Area for the 2008 8-hour ozone NAAQS. On
February 28, 2025, North Carolina submitted a separate SIP revision
containing the second 10-year maintenance plan to maintain the 2008 8-
hour ozone NAAQS in the bi-state Charlotte Area. In that submittal,
North Carolina seeks to move the vehicle I/M program to the contingency
measures section.\7\ EPA intends to finalize action on the second 10-
year maintenance plan for the North Carolina portion of the 2008 8-Hour
ozone maintenance area when it finalizes action on the I/M SIP
revision.
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\7\ CAA section 175A(d) requires that a maintenance plan include
such contingency measures, as necessary, to promptly correct any
violation of the NAAQS that occurs after redesignation of an area,
including the implementation of all measures with respect to control
of the air pollutant concerned that were contained in the SIP prior
to redesignation.
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III. EPA's Analysis of North Carolina's Submittal
A. North Carolina's NO<INF>X</INF> SIP Call Non-Interference Analysis
North Carolina's October 1, 2024, SIP revision includes a non-
interference demonstration to support the removal of the I/M program,
as required by section 110(l) of the CAA. EPA evaluates section 110(l)
non-interference demonstrations on a case-by-case basis considering the
circumstances of each SIP revision. Removal of the I/M program would
remove reliance on the I/M reduction credits gained from the 19
counties' participation in the I/M program in meeting the State's
NO<INF>X</INF> emissions budget. North Carolina has demonstrated that
it no longer needs these reduction credits to meet its obligation under
the NO<INF>X</INF> SIP Call.
As noted above, the federal and SIP-approved provisions that have
been implemented since the I/M program was initially added to the SIP
have resulted in adequate emission reductions such that the State
remains far below the NO<INF>X</INF> SIP Call budget. Specifically,
Table 1 compares the EGU NO<INF>X</INF> SIP Call budget to actual
emissions in 2007, 2021, 2022, and 2023.
Table 1--Comparison of Ozone Season NOX SIP Call Budget to Actual Emissions for EGUs
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2007 2021 2022 2023
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NOX SIP Call Budget (tons) *.................... 31,451 31,451 31,451 31,451
Actual Emissions (tons)......................... 24,177 12,291 11,525 11,957
Below Budget (tons)............................. 7,274 19,160 19,926 19,494
Below Budget (percent).......................... 23% 61% 63% 62%
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* From EPA's notice of proposed rulemaking for North Carolina's NOX SIP Call submission. See 67 FR 42519 (June
24, 2002).
Further, the State provided mobile source modeling results showing
that NO<INF>X</INF> emissions will remain below the NO<INF>X</INF> SIP
Call budgets after removal of the I/M program from the remaining 19
counties. Specifically, NCDAQ utilized EPA's MOVES4.0.1 to model mobile
source emissions increases. Table 2 shows the impact of the estimated
ozone season NO<INF>X</INF> emissions changes due to removal of the I/M
program. EGU emissions in 2023 were 11,957 tons, which is 19,494 tons
below the NO<INF>X</INF> SIP Call budget for EGUs. The proposed removal
of the I/M program would increase NO<INF>X</INF> mobile emissions by
1,190 tons across all 48 counties, collectively. NCDAQ estimates an
increase of 240 tons of NO<INF>X</INF> in removing I/M from the 19
counties covered by the SIP-approved I/M program. As noted above, EPA
previously approved removal of the other counties from the SIP-approved
program and revised MY coverage for certain counties. Including the
2023 NO<INF>X</INF> EGU emissions of 11,957 tons, the removal of the
remaining 19 counties in the I/M program would increase NO<INF>X</INF>
emissions by 240 tons per ozone season. This would still leave a margin
of 18,304 tons of NO<INF>X</INF> between the projected emissions and
the NO<INF>X</INF> budget.
Table 2--Impact of NOX Emissions Increases Due to Removal of the I/M
Program on NOX SIP Call I/M Credits
------------------------------------------------------------------------
I/M emissions increases from I/M program
removal Impact in tons/ozone season
------------------------------------------------------------------------
Removal of 26 counties from program 611
(previous action)......................
Revised MY coverage for 22 counties 311
(previous action)......................
Removal of three counties (previous 28
action)................................
[[Page 25260]]
Removal of 19 counties (this proposed 240
action) *..............................
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Total NOX Emission Increase......... 1,190
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* This NPRM only proposes to remove the I/M program from the remaining
19 counties.
Therefore, EPA is proposing to find that removing the I/M program
from the SIP would not interfere with the State's obligations under the
NO<INF>X</INF> SIP Call to meet its Statewide NO<INF>X</INF> emissions
budget. After the NO<INF>X</INF> SIP Call, the promulgation and
implementation of several federal rules and SIP-approved State
provisions, particularly those impacting EGUs, have created significant
NO<INF>X</INF> emissions reductions in the State that are more than
sufficient to meet its Statewide NO<INF>X</INF> emissions budget even
with the projected increase in NO<INF>X</INF> emissions from the
removal of the I/M program from the SIP.
B. North Carolina's NAAQS Non-Interference Analysis
North Carolina's non-interference demonstration includes an
analysis of how the removal of the I/M program will affect each
relevant NAAQS. The degree of analysis focused on any particular NAAQS
in a non-interference demonstration varies depending on the nature of
the emissions associated with the proposed SIP revision.
There are six NAAQS established to protect human health and the
environment. These NAAQS are CO, lead (Pb), nitrogen dioxide
(NO<INF>2</INF>), ozone, particulate matter (PM)--including
PM<INF>2.5</INF> (fine PM) and PM<INF>10</INF> (coarse PM), and
SO<INF>2</INF>. This demonstration addresses all NAAQS with a focus on
ozone (through its precursors NO<INF>X</INF> and volatile organic
compounds (VOCs)) and CO, the criteria pollutants targeted by I/M
programs. The demonstration also focuses on PM<INF>2.5</INF> as VOCs
and NO<INF>X</INF> emissions are precursors that react in the
atmosphere to form secondary fine PM. I/M programs are not designed to
address Pb and SO<INF>2</INF> \8\ emissions, and NO<INF>2</INF> is
captured generally through the same measures that target NO<INF>X</INF>
impacts. Therefore, this section focuses on NO<INF>2</INF>, ozone, CO,
and PM<INF>2.5</INF>. As previously mentioned, North Carolina is
designated as attainment for all NAAQS.
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\8\ The current design values in the counties affected by this
proposed action are attainment for the Pb and SO<INF>2</INF> NAAQS.
No reductions or emissions benefits are expected for the I/M program
for Pb or SO<INF>2</INF> as I/M programs are not designed to reduce
Pb or SO<INF>2</INF>. Emissions of both Pb and SO<INF>2</INF> are
addressed primarily through fuel standards for Pb and sulfur, which
have been greatly reduced over time in gasoline that powers on-road
motor vehicles.
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EPA reviews the ozone monitoring network annually that North
Carolina, Mecklenburg County Air Quality (MCAQ), Forsyth County Office
of Environmental Assistance and Protection (FCEAP), and Asheville-
Buncombe Air Quality Agency (ABAQA) operate and maintain in accordance
with 40 CFR part 58. North Carolina and the local agencies submit an
annual ambient air monitoring network plan as required by 40 CFR 58.10.
EPA reviews the network plan to ensure that it meets the air monitoring
network design requirements in 40 CFR part 58 and approves the plan if
it meets the minimum requirements. The network plan includes the ozone
monitoring network and the monitoring networks for PM, including
PM<INF>10</INF> and PM<INF>2.5</INF>, NO<INF>2</INF>, SO<INF>2</INF>,
CO, and Pb. The annual network plans developed by NCDAQ, MCAQ, FCEAP,
and ABAQA are posted for public inspection and comment for at least 30
days prior to submission to EPA, as required by 40 CFR 58.10(a)(1).
North Carolina submits a combined network plan for the State and the
local agencies. On October 29, 2025, EPA submitted a letter to North
Carolina stating that the air monitoring network plan meets the
requirements of 40 CFR part 58.\9\
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\9\ EPA also noted that the 2025 annual network plan needs an
addendum to provide additional information for two proposed ozone
sites and possibly for a proposed PM<INF>2.5</INF> site. EPA is
working with the State on this effort. The letter approving the
network plan is in the docket for this proposed rulemaking.
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i. Non-Interference Analysis for the Ozone NAAQS
EPA promulgated a revised 8-hour primary and secondary ozone
standard of 0.080 parts per million (ppm) on July 18, 1997.
Subsequently, on March 12, 2008, EPA published a final rule revising
both the primary and secondary NAAQS for ozone to a level of 0.075 ppm.
See 73 FR 16435 (March 27, 2008). On October 26, 2015, EPA published a
final rule lowering the level of the 8-hour primary and secondary ozone
NAAQS to 0.070 ppm. See 80 FR 65292. The 2015 ozone NAAQS retains the
same general form and averaging time as the 1997 ozone NAAQS and 2008
ozone NAAQS but is set at a lower level.
Under EPA's regulations at 40 CFR 50.19 and 40 CFR part 50,
Appendix U, the 2015 8-hour ozone NAAQS is attained when the 3-year
average of the annual fourth highest daily maximum 8-hour average
ambient ozone concentration is less than or equal to 0.070 ppm. In
2017, the entirety of North Carolina (including all the 19 counties
covered by this proposed rule) was designated attainment/unclassifiable
for the 2015 ozone NAAQS. See 82 FR 54232 (November 16, 2017).
Table 3 below shows the 2014-2016 through 2023-2025 ozone design
values for all ozone monitors in the 19 counties covered by this
proposed rule, demonstrating that these counties have maintained
compliance with all of the 8-hour ozone NAAQS mentioned above during
this time period.
Table 3--Ozone Design Values (DVs), ppm
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2014- 2015- 2016- 2017- 2018- 2019- 2020- 2021- 2022- 2023- 2025
Site name (county) AQS ID 2016 2017 2018 2019 2020 2021 2022 2023 2024 **
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bent Creek (Buncombe)...................... 37-021-0030 0.063 0.062 0.061 0.061 0.059 0.058 0.058 0.061 0.060 0.060
Wade (Cumberland).......................... 37-051-0008 0.061 0.062 0.063 0.062 0.060 0.059 * ND * ND * ND * ND
Honeycutt School (Cumberland).............. 37-051-0010 0.064 0.063 0.063 0.062 0.059 0.060 0.063 0.067 0.065 0.061
Wade School (Cumberland)................... 37-051-0011 * ND * ND * ND * ND * ND * ND * ND * ND 0.064 0.062
Durham Armory (Durham)..................... 37-063-0015 0.062 0.061 0.062 0.061 0.059 0.058 0.058 0.062 0.063 0.062
Hattie Avenue (Forsyth).................... 37-067-0022 0.067 0.067 0.066 0.065 0.064 0.064 0.063 0.065 0.065 0.066
[[Page 25261]]
Clemmons Middle (Forsyth).................. 37-067-0030 0.068 0.067 0.067 0.064 0.061 0.059 0.059 0.064 0.065 0.066
Union Cross (Forsyth)...................... 37-067-1008 0.067 0.066 0.066 0.064 0.061 0.060 0.059 0.061 0.062 0.064
Mendenhall School (Guilford)............... 37-081-0013 0.065 0.065 0.066 0.065 0.062 0.062 0.062 0.065 0.065 0.065
West Johnston (Johnston)................... 37-101-0002 0.065 0.063 0.063 0.061 0.059 0.060 0.061 0.064 0.063 0.062
Crouse (Lincoln)........................... 37-109-0004 0.067 0.067 0.065 0.064 0.060 0.061 0.061 0.065 0.064 0.063
Garinger High School (Mecklenburg)......... 37-119-0041 0.069 0.069 0.068 0.070 0.067 0.066 0.064 0.069 0.069 *** 0.068
University Meadows (Mecklenburg)........... 37-119-0046 0.070 0.070 0.070 0.069 0.067 0.066 0.064 0.068 0.069 \3\ 0.068
Castle Hayne (New Hanover)................. 37-129-0002 0.060 0.058 0.059 0.059 0.058 0.058 0.058 0.062 0.061 0.060
Rockwell (Rowan)........................... 37-159-0021 0.065 0.064 0.062 0.062 0.061 0.062 0.061 0.065 0.065 0.063
Monroe School (Union)...................... 37-179-0003 0.068 0.067 0.068 0.068 0.063 0.062 0.061 0.067 0.066 0.064
Millbrook School (Wake).................... 37-183-0014 0.065 0.066 0.066 0.064 0.060 0.060 0.060 0.063 0.064 0.061
--------------------------------------------------------------------------------------------------------------------------------------------------------
* No data. Indicates that a monitor does not have a valid design value for the three-year period because the monitor was not in operation or because the
monitoring data is incomplete.
** The 2023-2025 ozone design values are currently preliminary. The 2025 air monitoring data will be certified by May 1, 2026.
*** The critical 2026 4th maximum daily maximum 8-hour ozone concentrations that would result in a violating 2024-2026 design value for the 2015 8-hour
ozone NAAQS at the Garinger High School and University Meadows monitors are 0.082 ppm and 0.079 ppm, respectively. If the area would not violate the
2015 8-hour ozone NAAQS, it would also not violate the 1997 or the 2008 8-hour ozone NAAQS.
The Charlotte-Rock Hill, NC-SC Areas were designated nonattainment
for both the 1997 and 2008 8-hour ozone NAAQS. See 69 FR 23858 and 77
FR 30088. The North Carolina portion of the 1997 Charlotte Area was
redesignated to attainment and had its first 10-year maintenance plan
approved for the 1997 8-hour ozone NAAQS in a December 2, 2013, final
rule. See 78 FR 72036. The North Carolina portion of this area had its
second 10-year maintenance plan approved on January 13, 2023, and the
maintenance period ends in 2034. See 88 FR 2245. The design values used
to assess compliance with the 8-hour ozone NAAQS are calculated
according to the applicable procedures in 40 CFR part 50. Table 4 below
shows the ozone design values for the 1997 8-hour ozone Charlotte Area,
which encompasses the 2008 8-hour ozone Charlotte Area.
Table 4--DVs for the Entirety of the Counties in the 8-hour Ozone Charlotte Area, ppm
--------------------------------------------------------------------------------------------------------------------------------------------------------
2014- 2015- 2016- 2017- 2018- 2019- 2020- 2021- 2022- 2023- 2025
Site name (county) AQS ID 2016 2017 2018 2019 2020 2021 2022 2023 2024 **
--------------------------------------------------------------------------------------------------------------------------------------------------------
Crouse (Lincoln)........................... 37-109-0004 0.067 0.067 0.065 0.064 0.060 0.061 0.061 0.065 0.064 0.063
Garinger High School (Mecklenburg)......... 37-119-0041 0.069 0.069 0.068 0.070 0.067 0.066 0.064 0.069 0.069 *** 0.068
University Meadows (Mecklenburg)........... 37-119-0046 0.070 0.070 0.070 0.069 0.067 0.066 0.064 0.068 0.069 *** 0.068
Rockwell (Rowan)........................... 37-159-0021 0.065 0.064 0.062 0.062 0.061 0.062 0.061 0.065 0.065 0.063
Monroe School (Union)...................... 37-179-0003 0.068 0.067 0.068 * ND 0.063 0.062 0.061 0.067 0.066 0.064
Catawba Longhouse (York, SC)............... 45-091-8801 * ND * ND 0.063 0.064 0.062 0.062 0.060 0.064 0.065 * ND
--------------------------------------------------------------------------------------------------------------------------------------------------------
* No data. Indicates that a monitor does not have a valid design value for the three-year period because the monitor was not in operation or because the
monitoring data is incomplete.
** The 2023-2025 ozone design values are currently preliminary. They are expected to be validated by May 1, 2026.
*** The critical 2026 4th maximum daily maximum 8-hour ozone concentrations that would result in a violating 2024-2026 design value for the 2015 8-hour
ozone NAAQS at the Garinger High School and University Meadows monitors are 0.082 and 0.079, respectively.
The North Carolina portion of the 2008 8-hour ozone NAAQS Charlotte
Area was redesignated to attainment and had its first 10-year
maintenance plan approved for the 2008 8-hour ozone NAAQS in a July 28,
2015, final rule. See 80 FR 44873. North Carolina submitted its second
10-year maintenance plan for its portion of this area on February 28,
2025. As mentioned above, EPA intends to finalize action on the second
10-year maintenance plan for the North Carolina portion of this area
when it finalizes action on the I/M SIP revision. Design values used to
assess compliance with the 2008 8-hour ozone NAAQS are calculated
according to the applicable procedures in 40 CFR part 50. See Table 4
above.
In 2017, the entire state of North Carolina was designated as
``Attainment/Unclassifiable'' for the 2015 ozone NAAQS based on the
ozone season design values from 2014-2016. See 82 FR 54232. The
Garinger High School and University Meadows monitors are at 0.069 ppm
for the most recent certified design value (2022-2024) and 0.068 ppm
for the preliminary design values for 2023-2025. The 2026 critical 4th
maximum daily maximum 8-hour ozone concentration for the Charlotte-
Concord-Gastonia, NC-SC Metropolitan Statistical Area (i.e., Charlotte
MSA) is 0.079 ppm, based on the 2024 and 2025 monitored 4th maximum 8-
hour values of 0.068 ppm and 0.063 ppm, respectively. Even with the
emission increases projected from the removal of I/M, EPA believes that
it is unlikely that the Charlotte MSA's 4th maximum 8-hour value will
exceed 0.079 ppm in 2026 given the emissions analysis below, the fact
that the Charlotte MSA monitors have not recorded a 4th maximum above
0.079 ppm in the past 13 years (i.e., since 206), and the improvement
in ozone air quality across the Southeast during this time period. As a
result, EPA is proposing to determine that North Carolina has
demonstrated that the removal of the I/M program will not interfere
with attainment of the 2015 ozone NAAQS.
In North Carolina's submittal, the State showed that NO<INF>X</INF>
and VOC emissions would decrease over time in comparison to the 2014
base year emissions.\10\ The 2014 base year is an appropriate year for
comparison because it is one of the three years (i.e., 2014, 2015, and
2016) that was used to base the attainment/unclassifiable designations
in North Carolina for the 2015 8-hour ozone NAAQS. As older vehicles
are replaced with newer vehicles that emit less pollutants, NCDAQ
estimated a decline of 53 percent in NO<INF>X</INF> emissions in the
Charlotte Area counties from 2025 to
[[Page 25262]]
2035. Table 5 below shows the projected increase in NO<INF>X</INF> and
VOC emissions in 2025 associated with the removal of the I/M program
and compares 2014 base year emissions for the counties in the Charlotte
MSA.
---------------------------------------------------------------------------
\10\ See Figures 1 and 2 in the Public Notice Report (i.e.,
Appendix E of North Carolina's submission) as well as Table 20 in
North Carolina's submittal.
Table 5--County Level Anthropogenic Emissions for Charlotte MSA
[Tons per day (tpd)]
----------------------------------------------------------------------------------------------------------------
2014 Emissions Projected 2025 emissions Projected 2025 emissions
--------------------------- with I/M without I/M
Sector ----------------------------------------------------
NOX VOC NOX VOC NOX VOC
----------------------------------------------------------------------------------------------------------------
Onroad.......................... 60.15 34.32 31.62 22.60 32.25 23.56
Nonroad......................... 26.26 18.89 13.26 17.11 13.26 17.11
Point........................... 32.37 12.03 16.96 17.63 16.96 17.63
Nonpoint........................ 11.40 47.88 3.00 56.85 3.00 56.85
-------------------------------------------------------------------------------
Total....................... 130.18 113.12 64.84 114.19 65.47 115.14
----------------------------------------------------------------------------------------------------------------
% Reduction from 2014 Emissions. ........... ............ 50.19% -0.95% 49.71% -1.76%
----------------------------------------------------------------------------------------------------------------
Tables 6 and 7 below show the NO<INF>X</INF> and VOC emissions
changes from the proposed removal of the I/M program in the 19 counties
covered by the SIP-approved I/M program. This change in I/M
implementation was modeled with EPA's MOVES4.0.1 mobile emissions
model. The only changes to emissions occurred in the onroad sector.
These tables consider anthropogenic emissions only, meaning biogenic
emissions are excluded from the analysis.
Tables 5 and 6 show that the NO<INF>X</INF> emissions increase
across the Charlotte MSA would be 0.62 tpd, representing a 1.0 percent
increase in 2025 total area emissions. EPA is proposing that it is not
reasonable to conclude that an increase of 0.62 tpd would cause the
Charlotte Area MSA, whose critical value in 2026 is 0.079 ppm, to
violate the 2015 8-hour ozone NAAQS--the most stringent 8-hour ozone
NAAQS.
Table 6--Total County-Level Anthropogenic NOX Emissions for 2025 in the 19 Covered Counties
[tpd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Onroad Totals
------------------------------- Nonpoint ----------------------------------------
County With I/ Without Emissions Nonroad Point (area) With I/ Without Emissions Percent
M I/M change M I/M change change
--------------------------------------------------------------------------------------------------------------------------------------------------------
Charlotte-Gastonia-Salisbury Maintenance Area Counties for the 1997 and 2008 8-hour Ozone NAAQS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cabarrus.......................................... 3.09 3.15 0.06 1.19 1.64 0.24 6.16 6.22 0.06 1.0
Gaston............................................ 3.56 3.62 0.06 1.13 0.60 0.32 5.62 5.68 0.06 1.1
Iredell........................................... 3.98 4.04 0.06 0.97 2.06 0.29 7.30 7.36 0.06 0.8
Lincoln........................................... 1.60 1.63 0.03 0.37 0.79 0.11 2.87 2.90 0.03 1.0
Mecklenburg....................................... 13.44 13.75 0.31 6.49 7.70 1.51 29.14 29.45 0.31 1.1
Rowan............................................. 2.92 2.96 0.04 1.28 3.43 0.22 7.85 7.89 0.04 0.5
Union............................................. 3.03 3.09 0.06 1.82 0.73 0.31 5.90 5.96 0.06 1.0
-----------------------------------------------------------------------------------------------------
Subtotals..................................... 31.62 32.25 0.63 13.26 16.96 3.00 64.84 65.46 0.62 1.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Triangle 1997 Ozone NAAQS Maintenance Area Counties (Raleigh/Durham/Chapel Hill)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Durham............................................ 3.92 4.01 0.09 1.70 1.20 0.51 7.33 7.42 0.09 1.2
Franklin.......................................... 0.98 1.00 0.02 0.27 0.57 0.08 1.89 1.91 0.02 1.1
Johnston.......................................... 4.07 4.14 0.07 1.47 0.67 0.24 6.45 6.52 0.07 1.1
Wake.............................................. 11.01 11.29 0.28 4.80 3.29 1.21 20.31 20.59 0.28 1.4
-----------------------------------------------------------------------------------------------------
Subtotals..................................... 19.98 20.43 0.45 8.24 5.73 2.04 35.67 36.12 0.45 1.3
--------------------------------------------------------------------------------------------------------------------------------------------------------
Triad 1997 Ozone NAAQS Attainment Area Counties (Greensboro/Winston-Salem/High Point)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Davidson.......................................... 2.85 2.90 0.05 1.55 2.56 0.24 7.20 7.25 0.05 0.7
Forsyth........................................... 5.19 5.30 0.11 1.50 1.77 0.52 8.98 9.09 0.11 1.2
Guilford.......................................... 6.87 7.01 0.14 3.95 1.96 0.86 13.64 13.78 0.14 1.0
-----------------------------------------------------------------------------------------------------
Subtotals..................................... 14.91 15.21 0.30 7.00 6.29 1.61 29.81 30.11 0.30 1.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Other Counties (Not Subject to an Ozone Maintenance Plan)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Alamance.......................................... 2.57 2.62 0.04 0.95 0.48 0.25 4.25 4.30 0.05 1.2
Buncombe.......................................... 3.83 3.90 0.07 1.31 0.72 0.45 6.31 6.38 0.07 1.1
Cumberland........................................ 3.81 3.88 0.07 1.58 3.36 0.29 9.03 9.10 0.07 0.8
New Hanover....................................... 1.84 1.89 0.05 2.13 1.96 0.28 6.20 6.25 0.05 0.8
Randolph.......................................... 2.88 2.92 0.04 0.78 0.26 0.24 4.16 4.20 0.04 0.9
-----------------------------------------------------------------------------------------------------
Subtotals..................................... 14.93 15.21 0.28 6.74 6.77 1.51 29.96 30.24 0.28 0.9
-----------------------------------------------------------------------------------------------------
Totals.................................... 81.44 83.09 1.66 35.24 35.75 8.16 160.59 162.25 1.66 1.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 25263]]
Tables 5 and 7 show the VOC emissions increase across the Charlotte
Area MSA would be 0.95 tpd, representing a 0.83 percent increase in
total area emissions.\11\ EPA is proposing that it is not reasonable to
conclude that an increase of 0.95 tpd would cause the Charlotte Area
MSA, whose critical value in 2026 is 0.079 ppm, to violate the 2015 8-
hour ozone NAAQS--the most stringent of the 8-hour ozone NAAQS. As
mentioned above, even with the emission increases projected from the
removal of I/M, EPA believes that it is unlikely that the Charlotte
MSA's 4th maximum 8-hour value will exceed 0.079 ppm in 2026 given the
emissions analysis below, the fact that the Charlotte MSA monitors have
not recorded a 4th maximum above 0.079 ppm in the past 13 years (i.e.,
since 2012), and the improvement in ozone air quality across the
Southeast during this time period.
---------------------------------------------------------------------------
\11\ North Carolina rounds to two decimal places for emissions
totals and one decimal place for the summary percentages in its
submittal, as reproduced in Tables 4 and 5.
Table 7--Total County-Level Anthropogenic VOC Emissions for 2025
[tpd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Onroad Totals
------------------------------- Nonpoint ----------------------------------------
County With I/ Without Emissions Nonroad Point (area) With I/ Without Emissions Percent
M I/M change M I/M change change
--------------------------------------------------------------------------------------------------------------------------------------------------------
Charlotte-Gastonia-Salisbury Maintenance Area Counties for the 1997 and 2008 8-hour Ozone NAAQS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cabarrus.......................................... 2.34 2.43 0.10 1.19 1.17 4.84 9.55 9.64 0.09 0.9
Gaston............................................ 2.55 2.65 0.09 1.13 1.51 5.52 10.72 10.82 0.10 0.9
Iredell........................................... 2.70 2.79 0.09 0.84 1.54 4.94 10.03 10.12 0.09 0.9
Lincoln........................................... 1.26 1.30 0.04 0.46 2.69 2.15 6.56 6.60 0.04 0.6
Mecklenburg....................................... 9.09 9.55 0.46 10.56 3.07 28.43 51.14 51.60 0.46 0.9
Rowan............................................. 2.21 2.28 0.07 0.80 5.46 4.06 12.52 12.59 0.07 0.6
Union............................................. 2.45 2.55 0.11 2.12 2.19 6.91 13.68 13.78 0.10 0.7
-----------------------------------------------------------------------------------------------------
Subtotals..................................... 22.60 23.56 0.96 17.11 17.63 56.85 114.19 115.14 0.95 0.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
Triangle 1997 Ozone NAAQS Maintenance Area Counties (Raleigh/Durham/Chapel Hill)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Durham............................................ 2.83 2.96 0.13 1.82 0.64 6.83 12.12 12.25 0.13 1.1
Franklin.......................................... 0.83 0.86 0.03 0.36 5.36 1.71 8.26 8.29 0.03 0.4
Johnston.......................................... 2.59 2.70 0.11 1.06 2.24 6.38 12.28 12.39 0.11 0.9
Wake.............................................. 8.77 9.24 0.48 7.99 2.63 24.47 43.86 44.33 0.47 1.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Subtotals..................................... 15.03 15.77 0.75 11.23 10.88 39.38 76.51 77.25 0.74 1.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Triad 1997 Ozone NAAQS Attainment Area Counties (Greensboro/Winston-Salem/High Point)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Davidson.......................................... 2.31 2.39 0.08 0.89 2.09 3.48 8.77 8.85 0.08 0.9
Forsyth........................................... 4.00 4.16 0.16 2.05 3.63 7.22 16.91 17.07 0.16 0.9
Guilford.......................................... 5.02 5.24 0.21 4.54 8.66 11.42 29.64 29.86 0.22 0.7
-----------------------------------------------------------------------------------------------------
Subtotals..................................... 11.33 11.78 0.45 7.48 14.38 22.12 55.31 55.77 0.46 0.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
Other Counties (Not Subject to an Ozone Maintenance Plan)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Alamance.......................................... 1.99 2.06 0.07 1.50 2.11 4.54 10.13 10.20 0.07 0.7
Buncombe.......................................... 2.83 2.94 0.11 1.86 2.87 6.39 13.95 14.06 0.11 0.8
Cumberland........................................ 2.74 2.86 0.12 1.83 6.60 7.13 18.30 18.42 0.12 0.7
New Hanover....................................... 1.79 1.88 0.09 1.97 2.53 4.82 11.11 11.20 0.09 0.8
Randolph.......................................... 2.06 2.13 0.06 0.90 2.54 5.36 10.87 10.94 0.07 0.6
-----------------------------------------------------------------------------------------------------
Subtotals..................................... 11.42 11.87 0.46 8.05 16.64 28.25 64.35 64.81 0.46 0.7
-----------------------------------------------------------------------------------------------------
Totals.................................... 60.37 62.99 2.61 43.87 59.53 146.61 310.36 312.97 2.61 0.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
Regarding maintenance of the 2008 8-hour ozone Charlotte Area,
Table 8 \12\ shows that the 2025 projected emissions without I/M are 54
percent below 2014 baseline NO<INF>X</INF> emissions and 7.8 percent
below 2014 baseline VOC emissions. Thus, the Charlotte Area is
projected to maintain the NAAQS even with removal of the I/M program.
As mentioned above, EPA intends to finalize action on the second 10-
year maintenance plan for the North Carolina portion of this area when
it finalizes action on the I/M SIP revision.
---------------------------------------------------------------------------
\12\ The emissions reflect activity that occurs in the portion
of each of the six counties included in the 2008 8-hour ozone
maintenance area plus all of Mecklenburg County. Therefore, for the
six partial counties, the increase in emissions attributable to the
maintenance area is lower than the increases presented in Table 5,
which reflects the values for the 1997 8-hour ozone maintenance area
and includes the entirety of the six counties in the 2008 8-hour
ozone maintenance area in addition to all of Mecklenburg County.
[[Page 25264]]
Table 8--Demonstration of Maintenance for NOX and VOC Anthropogenic Emissions for the 2008 Ozone Charlotte Area
With I/M Removal
----------------------------------------------------------------------------------------------------------------
Maintenance plan 2014
Pollutant attainment year 2025 Projected emissions % Below 2014
emissions (tons/day) * without I/M (tons/day) emissions)
----------------------------------------------------------------------------------------------------------------
NOX...................................... 130.18 59.27 -54
VOC...................................... 113.12 104.32 -7.8
----------------------------------------------------------------------------------------------------------------
* For more information on the 2014 attainment year inventory and initial projected 2026 maintenance year
inventory, see the May 21, 2015, NPRM (80 FR 29250), as approved in the July 28, 2015, NFRM (80 FR 44873).
As mentioned above, the entire state of North Carolina was
designated as attainment/unclassifiable for the 2015 8-hour ozone
NAAQS, so there is no analogous table to Table 8 for the 2015 8-hour
ozone NAAQS; however, EPA believes it is reasonable to conclude that a
54 percent reduction in NO<INF>X</INF> emissions and a 7.8 percent
reduction in VOC emissions from the 2014 baseline emissions is still
consistent with attainment of the 2015 8-hour ozone NAAQS. 2014 was one
of the three years used to calculate the design value that supported
the attainment/unclassifiable designation for the 2015 8-hour ozone
NAAQS in North Carolina.
ii. Non-Interference Analysis for the Fine Particulate Matter
(PM<INF>2.5</INF>) NAAQS
Over the years, EPA has reviewed and revised the PM<INF>2.5</INF>
NAAQS several times. On July 18, 1997, EPA established an annual
PM<INF>2.5</INF> NAAQS of 15.0 micrograms per cubic meter ([mu]g/m\3\),
based on a 3-year average of annual mean PM<INF>2.5</INF>
concentrations, and a 24-hour PM<INF>2.5</INF> NAAQS of 65 [mu]g/m\3\,
based on a 3-year average of the 98th percentile of 24-hour
concentrations. See 62 FR 36852. On September 21, 2006, EPA retained
the 1997 annual PM<INF>2.5</INF> NAAQS of 15.0 [mu]g/m\3\ but revised
the 24-hour PM<INF>2.5</INF> NAAQS to 35 [mu]g/m\3\, based again on a
3-year average of the 98th percentile of 24-hour concentrations. See 71
FR 61144. On December 14, 2012, EPA retained the 2006 24-hour
PM<INF>2.5</INF> NAAQS of 35 [mu]g/m\3\ but revised the annual primary
PM<INF>2.5</INF> NAAQS to 12.0 [mu]g/m\3\, based again on a 3-year
average of annual mean PM<INF>2.5</INF> concentrations. See 78 FR 3086.
On March 6, 2024, EPA revised the annual primary PM<INF>2.5</INF> NAAQS
to 9.0 [mu]g/m\3\, based again on a 3-year average of annual mean
PM<INF>2.5</INF> concentrations. See 89 FR 16202.
EPA promulgated designations for the 1997 Annual PM<INF>2.5</INF>
NAAQS on January 5, 2005. See 70 FR 944. The Greensboro-Winston Salem-
High Point, NC Area, which contains Davidson and Guilford County, and
the Hickory-Morganton-Lenoir, NC Area, which contains Catawba County,
were designated as nonattainment on that date. On November 18, 2011,
EPA redesignated the Greensboro-Winston Salem-High Point, NC Area and
the Hickory-Morganton-Lenoir Area to attainment. See 76 FR 71455 and 76
FR 71452. On November 13, 2009, and on January 15, 2015, EPA published
notices determining that the entire state of North Carolina was
unclassifiable/attainment for the 2006 24-hour PM<INF>2.5</INF> NAAQS
and the 2012 annual PM<INF>2.5</INF> NAAQS, respectively. See 74 FR
58688 and 80 FR 2206, respectively.
As stated earlier, in 2024 the annual primary PM<INF>2.5</INF>
NAAQS was revised to 9.0 [mu]g/m\3\, based again on a 3-year average of
annual mean PM<INF>2.5</INF> concentrations. Currently, all monitors in
North Carolina are attaining the 2024 annual PM<INF>2.5</INF>
NAAQS.<SUP>13 14</SUP>
---------------------------------------------------------------------------
\13\ Air quality design values are available on the EPA website
at: <a href="https://www.epa.gov/air-trends/air-quality-design-values">https://www.epa.gov/air-trends/air-quality-design-values</a>.
\14\ On February 6, 2025, the State of North Carolina submitted
an exceptional events (EEs) demonstration for 13 days at the Remount
Road monitor (AQS ID 37-119-0045) in Mecklenburg County in the June-
July 2023 period to address impacts from the 2023 Canadian
wildfires. On September 2, 2025, EPA issued a letter concurring on
six of the 13 days and deferring action on the remaining seven days.
With the six excluded days, the Remount Road monitor showed an
attaining 2022-2024 design value for the 2024 annual
PM<INF>2.5</INF> NAAQS of 9.0 [micro]g/m\3\. A copy of the September
2, 2025, letter is included in the docket for this NPRM.
---------------------------------------------------------------------------
North Carolina's October 1, 2024, SIP revision concludes that the
removal of the I/M program would not interfere with attainment or
maintenance of the PM<INF>2.5</INF> NAAQS. As noted above in the
``Totals'' row from Tables 6 and 7, the modeled increase in precursor
emissions of NO<INF>X</INF> and VOCs is projected to be 1.66 tpd (1.0
percent) and 2.61 tpd (0.8 percent), respectively, across all 19
covered counties. For these reasons, EPA proposes to find that removal
of the I/M program would not interfere with maintenance of the
PM<INF>2.5</INF> NAAQS.
iii. Non-Interference Analysis for the 2010 NO<INF>2</INF> NAAQS
The 2010 NO<INF>2</INF> 1-hour standard is set at 100 ppb, based on
the 3-year average of the 98th percentile of the yearly distribution of
1-hour daily maximum concentrations. The 1971 annual NO<INF>2</INF>
standard of 53 ppb is based on the annual mean concentration. On
February 17, 2012, EPA designated all counties in North Carolina as
unclassifiable/attainment for the 2010 NO<INF>2</INF> NAAQS. See 77 FR
9532.
Based on the technical analysis in North Carolina's October 1,
2024, SIP revision, the projected increase in total anthropogenic
NO<INF>X</INF> emissions (of which NO<INF>2</INF> is a component)
associated with the removal of the I/M program ranges from a 0.02 tpd
increase in total NO<INF>X</INF> emissions (1.1 percent) for Franklin
County to a 0.31 tpd increase in total NO<INF>X</INF> emissions (1.1
percent) for Mecklenburg County in 2025. The DVs \15\ from all
NO<INF>2</INF> monitors in the State are attaining the 2010 1-hour
NO<INF>2</INF> standard and the 1971 annual NO<INF>2</INF> standard.
The highest-reading monitor in the State, the Equipment Drive monitor
in Mecklenburg County (AQS ID: 37-119-0050), has a DV of 13 ppb for the
annual NAAQS. The form of the annual NAAQS is a single year arithmetic
mean. The form of the 2010 1-hour NAAQS requires three complete years
of data. The Equipment Drive monitor does not yet have a complete
three-year DV for the 1-hour NAAQS because it began operation in
January 2024. The highest valid DV for the 1-hour NO<INF>2</INF> NAAQS
in the State is the Remount Road Monitor (37-119-0045) at 36 ppb.
---------------------------------------------------------------------------
\15\ Air quality design values are available on EPA's website
at: <a href="https://www.epa.gov/air-trends/air-quality-design-values">https://www.epa.gov/air-trends/air-quality-design-values</a>.
---------------------------------------------------------------------------
Given the margin between the NAAQS and the DVs for the annual and
1-hour NAAQS and the size of the projected increases in NO<INF>X</INF>
emissions due to the removal of I/M, EPA proposes to find that removal
of the I/M program would not interfere with maintenance of the
NO<INF>2</INF> NAAQS.
iv. Non-Interference Analysis for the CO NAAQS
EPA promulgated the CO NAAQS in 1971 and has retained the primary
standard since its last review of the standard in 2011. The primary
NAAQS for CO include: (1) an 8-hour standard
[[Page 25265]]
of 9.0 ppm, measured using the annual second highest 8-hour
concentration for two consecutive years as the design value; and (2) a
1-hour average of 35 ppm, using the second highest 1-hour average
within a given year. In 1995, Mecklenburg, Durham, and Wake County were
redesignated from nonattainment to unclassifiable/attainment, and
Forsyth County was redesignated to unclassifiable/attainment in 1994.
See 59 FR 48399 (September 21, 1994) and 60 FR 39258 (August 2, 1995).
North Carolina inventoried the emissions of CO from all
anthropogenic sources for 2025, with and without the I/M program from
the remaining 19 counties, showing an overall 6.4 percent projected
increase in CO emissions. See Table 9 below. The highest 2023-2024 CO
DVs \16\ in the Charlotte (Mecklenburg County) metropolitan area are
1.6 ppm for the 8-hour CO DV and 2.0 ppm for the 1-hour DV at the
Remount Road site (AQS ID: 37-119-0045). The highest 2022-2024 CO DVs
in the Raleigh (Wake County) metropolitan area are 1.3 ppm for the 8-
hour CO design value and 1.7 ppm for the 1-hour design value at the
Millbrook School site (AQS ID: 37-183-0014). Given the margin between
the NAAQS and the DVs for the 8-hour and 1-hour CO NAAQS and the size
of the CO increases, EPA proposes to find that removal of the I/M
program would not interfere with maintenance of the CO NAAQS.
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\16\ Air quality design values are available on EPA's website
at: <a href="https://www.epa.gov/air-trends/air-quality-design-values">https://www.epa.gov/air-trends/air-quality-design-values</a>.
Table 9--Total County-Level Anthropogenic CO Emissions for 2025 (tpd)
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Onroad Nonroad Point Nonpoint (area) Totals
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County Without Emissions With I/ Without With I/ Without With I/ Without Without Emissions Percent
With I/M I/M increase M I/M M I/M M I/M With I/M I/M increase increase
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Charlotte-Gastonia-Salisbury Maintenance Area Counties for the 1997 and 2008 8-hour Ozone NAAQS
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Cabarrus.................................................... 39.38 44.07 4.69 22.33 22.33 1.45 1.45 2.52 2.52 65.69 70.38 4.69 7.1
Gaston...................................................... 43.02 47.78 4.76 20.87 20.87 1.14 1.14 2.70 2.70 67.72 72.48 4.76 7.0
Iredell..................................................... 43.99 48.64 4.65 14.07 14.07 2.23 2.23 2.51 2.51 62.79 67.44 4.65 7.4
Lincoln..................................................... 18.32 20.15 1.83 7.60 7.60 2.10 2.10 1.27 1.27 29.29 31.12 1.83 6.2
Mecklenburg................................................. 194.21 220.33 26.12 200.48 200.48 22.16 22.16 7.55 7.55 424.40 450.52 26.12 6.2
Rowan....................................................... 35.52 39.05 3.53 12.24 12.24 3.61 3.61 1.79 1.79 53.17 56.70 3.53 6.6
Union....................................................... 39.01 43.61 4.60 39.19 39.19 4.46 4.46 3.03 3.03 85.69 90.29 4.60 5.4
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Subtotals............................................... 413.45 463.63 50.18 316.79 316.79 37.15 37.15 21.36 21.36 788.75 838.93 50.18 6.4
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Triangle 1997 Ozone NAAQS Maintenance Area Counties (Raleigh/Durham/Chapel Hill)
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Durham...................................................... 58.60 66.24 7.64 32.41 32.41 1.04 1.04 3.86 3.86 95.91 103.55 7.64 8.0
Franklin.................................................... 11.67 12.92 1.25 6.42 6.42 20.93 20.93 1.02 1.02 40.03 41.28 1.25 3.1
Johnston.................................................... 44.11 49.24 5.13 17.71 17.71 2.65 2.65 2.70 2.70 67.17 72.30 5.13 7.6
Wake........................................................ 164.05 186.03 21.98 149.29 149.29 7.89 7.89 8.03 8.03 329.26 351.24 21.98 6.7
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Subtotals............................................... 278.43 314.43 36.00 205.83 205.83 32.50 32.50 15.61 15.61 532.37 568.37 36.00 6.8
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Triad 1997 Ozone NAAQS Attainment Area Counties (Greensboro/Winston-Salem/High Point)
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Davidson.................................................... 33.13 36.37 3.25 15.49 15.49 1.20 1.20 2.21 2.21 52.03 55.27 3.24 6.2
Forsyth..................................................... 69.28 77.28 8.00 40.82 40.82 2.26 2.26 3.07 3.07 115.44 123.44 8.00 6.9
Guilford.................................................... 89.99 100.83 10.85 90.05 90.05 3.09 3.09 5.21 5.21 188.35 199.19 10.84 5.8
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Subtotals............................................... 192.39 214.49 22.10 146.37 146.37 6.55 6.55 10.49 10.49 355.81 377.89 22.08 6.2
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Other Counties (Not Subject to an Ozone Maintenance Plan)
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Alamance.................................................... 28.91 31.99 3.08 28.60 28.60 3.93 3.93 2.01 2.01 63.44 66.52 3.08 4.9
Buncombe.................................................... 42.99 47.66 4.66 26.69 26.69 1.48 1.48 4.37 4.37 75.52 80.19 4.67 6.2
Cumberland.................................................. 50.44 56.61 6.17 31.77 31.77 5.28 5.28 2.67 2.67 90.17 96.34 6.17 6.8
New Hanover................................................. 29.98 33.80 3.82 32.98 32.98 1.45 1.45 2.33 2.33 66.74 70.56 3.82 5.7
Randolph.................................................... 28.45 31.12 2.67 17.22 17.22 0.48 0.48 1.78 1.78 47.93 50.60 2.67 5.6
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Subtotals............................................... 180.77 201.18 20.40 137.26 137.26 12.63 12.63 13.15 13.15 343.81 364.22 20.41 5.9
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Totals.............................................. 1065.04 1193.71 128.68 806.25 806.25 88.84 88.84 60.61 60.61 2020.74 2149.41 128.67 6.4
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IV. Incorporation by Reference
In this document, EPA is proposing to include in a final EPA rule
amended regulatory text that includes incorporation by reference. EPA
is proposing to remove Rules 15A NCAC 02D.1001, Purpose; Rule .1002,
Applicability; Rule .1003, Definitions; and Rule .1005, On-Board
Diagnostic Standards from the North Carolina SIP, which were
incorporated by reference in accordance with the requirements of 1 CFR
part 51, as discussed in Sections I through III of this preamble. EPA
has made and will continue to make the SIP generally available at the
EPA Region 4 Office (please contact the person identified in the For
Further Information Contact section of this preamble for more
information).
V. Proposed Action
EPA is proposing to find that removal of the I/M program from the
North Carolina SIP would not interfere with any applicable requirement
concerning attainment and RFP or any other applicable requirement of
the CAA. Consequently, EPA is proposing to approve North Carolina's
October 1, 2024, SIP revision and remove the I/M program from North
Carolina's SIP.
[[Page 25266]]
VI. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA and applicable
Federal regulations. See 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:
<bullet> 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);
<bullet> Is not an Executive Order 14192 (90 FR 9065, February 6,
2025) regulatory action because this action is not significant under
Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> 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.);
<bullet> 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);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> 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.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian Tribe has
demonstrated that a Tribe has jurisdiction. In those areas of Indian
country, the rule does not have Tribal implications and will not impose
substantial direct costs on Tribal governments or preempt Tribal law as
specified by Executive Order 13175. See 65 FR 67249, November 9, 2000.
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Carbon Monoxide,
Incorporation by reference, Intergovernmental relations, Nitrogen
dioxide, Ozone, Particulate matter, Sulfur oxides, Volatile organic
compounds.
(Authority: 42 U.S.C. 7401 et seq.)
Dated: May 5, 2026.
Kristy Eubanks,
Deputy Regional Administrator performing the functions and duties of
the Regional Administrator, Region 4.
[FR Doc. 2026-09146 Filed 5-7-26; 8:45 am]
BILLING CODE 6560-50-P
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