[Federal Register Volume 60, Number 128 (Wednesday, July 5, 1995)]
[Rules and Regulations]
[Pages 34859-34867]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-16358]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 52 and 81
[NC-061-1-7010; FRL-5226-3]
Approval and Promulgation of Implementation Plans and Designation
of Areas for Air Quality Planning Purposes; State of North Carolina
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: EPA is approving a maintenance plan and a request to
redesignate the Charlotte-Gastonia area from nonattainment to
attainment for ozone (O3) submitted on November 12, 1993, by the
State of North Carolina through the North Carolina Department of
Environment, Health, and Natural Resources. Subsequently on December
16, 1994, January 6, 1995, and May 23, 1995, the State submitted
supplementary information which included refined modeling and revisions
to the maintenance plan. The Charlotte-Gastonia O3 nonattainment
area includes Mecklenburg and Gaston Counties. EPA is also approving
the State of North Carolina's 1990 baseline emissions inventory because
it meets EPA's requirements regarding the approval of baseline emission
inventories.
EFFECTIVE DATE: July 5, 1995.
ADDRESSES: Copies of the documents relative to this action are
available for public inspection during normal business hours at the
following locations. The interested persons wanting to examine these
documents should make an appointment with the appropriate office at
least 24 hours before the visiting day.
Air and Radiation Docket and Information Center (Air Docket 6102), U.S.
Environmental Protection Agency, 401 M Street, SW, Washington, DC
20460.
Environmental Protection Agency, Region 4 Air Programs Branch, 345
Courtland Street, NE, Atlanta, Georgia 30365.
State of North Carolina, Air Quality Section, Division of Environmental
Management, North Carolina Department of Environment, Health, and
Natural Resources, Raleigh, North Carolina 27626.
Environmental Management Division, Mecklenburg County Department of
Environmental Protection, 700 N. Tryon Street, Charlotte, North
Carolina 28202-2236.
FOR FURTHER INFORMATION CONTACT: Kay Prince, Regulatory Planning and
Development Section, Air Programs Branch, Air, Pesticides & Toxics
Management Division, Region 4 Environmental Protection Agency, 345
Courtland Street, NE, Atlanta, Georgia 30365. The telephone number is
404/347-3555 extension 4221. Reference file NC-061-1-6815.
SUPPLEMENTARY INFORMATION: On November 15, 1990, the Clean Air Act
Amendments of 1990 were enacted. (Pub. L. 101-549, 104 Stat. 2399,
codified at 42 U.S.C. 7401-7671q). Under section 107(d)(1)(C), EPA
designated Mecklenburg County of the Charlotte-Gastonia area as
nonattainment by operation of law with respect to O3 because the
area was designated nonattainment immediately before November 15, 1990.
The nonattainment area was expanded to include Gaston County per
section 107(d)(1)(A)(i) (See 56 FR 56694 (Nov. 6, 1991) and 57 FR 56762
(Nov. 30, 1992), codified at 40 CFR 81.318.) The area was classified as
moderate.
The moderate nonattainment area had ambient monitoring data that
showed no violations of the O3 NAAQS, during the period from 1990
through 1993. Therefore, on November 12, 1993, the State of North
Carolina submitted an O3 maintenance plan and requested
redesignation of the area to attainment with respect to the O3
NAAQS. The O3 NAAQS continues to be maintained in the Charlotte-
Gastonia area. On January 24, 1994, Region 4 determined that the
information received from the State constituted a complete
redesignation request under the general completeness criteria of 40 CFR
51, appendix V, sections 2.1 and 2.2. Subsequently, on December 16,
1994, and January 6, 1995, the State submitted additional information
that refined the modeling and clarified the future measures needed to
ensure maintenance of the O3 NAAQS. The State requested the
January 6, 1995, information be parallel processed by EPA. The State
held a public hearing on April 19, 1995, and made a final submittal to
EPA on May 23, 1995.
The North Carolina redesignation request for the Charlotte-Gastonia
moderate O3 nonattainment area meets the five requirements of
section 107(d)(3)(E) for redesignation to attainment. The following is
a brief description of how the State of North Carolina has fulfilled
each of these requirements. Because the maintenance plan is a critical
element of the redesignation request, EPA will discuss its evaluation
of the maintenance plan under its analysis of the redesignation
request.
1. The Area Must Have Attained the O3 NAAQS
The State of North Carolina's request is based on an analysis of
quality assured ambient air quality monitoring data, which is relevant
to the maintenance plan and to the redesignation request. Most recent
ambient air quality monitoring data for calendar year 1990 through
calendar year 1994 demonstrates attainment of the standard. The State
of North Carolina has committed to continue monitoring the moderate
nonattainment area in accordance with 40 CFR 58. Therefore, the State
has met this requirement. For detailed information refer to the
proposed document published April 17, 1995 (60 FR 19197).
[[Page 34860]]
2. The Area Has Met All Applicable Requirements Under Section 110
and Part D of the CAA
EPA reviewed the North Carolina SIP and ensures that it contains
all measures due under the amended CAA prior to or at the time the
State of North Carolina submitted its redesignation request. For
detailed information regarding applicable requirements other than
section 182(f), refer to the proposed document.
A. Section 182(a)(1)--Emissions Inventory
North Carolina has met this requirement. This document gives final
approval of the 1990 base line emissions inventory. For detailed
information regarding how this requirement was met, refer to the
proposal document.
B. Section 182(a)(2), 182(b)(2)--Reasonably Available Control
Technology (RACT)
As stated in the proposal document, North Carolina had met all RACT
requirements except those in 182(b)(2), RACT Catch-ups. On January 7,
1994, the State submitted revisions to the SIP that addressed the RACT
Catch-ups. The document approving those revisions was published on
January 26, 1995 (see 60 FR 5138), and became effective on March 27,
1995. Therefore this requirement has been met. For detailed information
regarding this requirement, refer to the proposal document.
C. Section 182(a)(3)--Emissions Statements
In the proposal document, EPA stated that the North Carolina
Emissions Statement regulation must be approved prior to or at the time
of redesignation. On December 17, 1993, North Carolina submitted a
revision to the SIP that met the requirements for an emission statement
regulation. The document approving this revision was published on May
5, 1995 (see 60 FR 22284). No adverse comments were received,
therefore, the effective date of the federal approval is July 5, 1995.
Therefore this requirement has been met. For detailed information
regarding this requirement, refer to the proposal document.
D. Section 182(b)(1)--15% Progress Plans
With the approval of this redesignation request, the requirement to
submit a 15% plan is obviated because the redesignation request
predated the requirement for a 15% plan. Additionally, on May 10, 1995,
EPA, in a memorandum from John S. Seitz, Director, Office of Air
Quality Planning and Standards, issued a new policy regarding planning
requirements of the CAA. Areas that have quality assured air monitoring
data showing attainment with the ozone standard for the most recent
three years are deemed to have attained the standard and such are not
subject to certain requirements of subpart 2 of Part D of title I of
the CAA. Specifically, a moderate area such as Charlotte-Gastonia would
no longer be required to submit a 15% plan or an attainment
demonstration. EPA has published a document making such finding with
respect to the Charlotte-Gastonia area. See the proposal document for
more detailed information.
E. Section 182(b)(3)--Stage II
On January 24, 1994, EPA promulgated the onboard vapor recovery
rule (OBVR), and, section 202(a)(b) of the CAA provides that once the
rule is promulgated, moderate areas are no longer required to implement
Stage II. Thus, the Stage II vapor recovery requirement of section
182(b)(3) is no longer an applicable requirement. See the proposal
document for more detailed information.
F. Section 182(b)(4)--Motor Vehicle Inspection and Maintenance (I/M)
In the proposal document, EPA stated that the North Carolina I/M
regulation must be approved prior to or at the time of redesignation.
On July 19, 1993, North Carolina submitted a revision to the SIP that
met the requirements for an I/M regulation. The document approving this
revision was published on June 2, 1995 (see 60 FR 28720), and the
revision is federally approved. For detailed information regarding this
requirement, refer to the proposal document.
G. Section 182(b)(5)--New Source Review (NSR)
North Carolina has a fully-approved NSR program for moderate
O3 nonattainment areas. For detailed information regarding this
requirement, refer to the proposal document.
H. Section 182(f)--Oxides of Nitrogen (NOX) Requirements
This redesignation request predated the November 15, 1993,
requirement for the submittal of NOX RACT rules. Therefore,
NOX RACT is not an applicable requirement for purposes of this
redesignation request. However, the State has submitted revisions that
would require NOX RACT should the area violate the O3 NAAQS.
This submittal pre-adopts NOX RACT rules as a contingency measure.
Since contingency measures for maintenance are not required to be pre-
adopted, approval of this submittal is not a requirement for
redesignation. Action on that submittal will be taken in another
document since it is not an applicable requirement for purposes of this
redesignation request. For more detailed information regarding this
requirement, refer to the proposal document.
3. The Area Has a Fully Approved SIP Under Section 110(k) of the
CAA
Based on the approval of provisions under the pre-amended CAA and
EPA's prior approval of SIP revisions under the amended CAA, EPA has
determined that the Charlotte-Gastonia area has a fully approved
O3 SIP under section 110(k).
4. The Air Quality Improvement Must Be Permanent and Enforceable
Several control measures have come into place since the Charlotte-
Gastonia nonattainment area violated the O3 NAAQS. Of these
control measures, the reduction of fuel volatility from 10.6 psi in
1987 to less than 9.0 psi in 1990, and finally to less than 7.8 psi
beginning with the summer of 1992, as measured by the Reid Vapor
Pressure (RVP), and fleet turnover due to the Federal Motor Vehicle
Control Program (FMVCP) produced the most significant decreases in VOC
emissions. The reduction in VOC emissions due to the mobile source
regulations from 1987 to 1990 is 26.01 tons per day (29.63%). The VOC
emissions in the base year are not artificially low due to a depressed
economy.
5. The Area Must Have a Fully Approved Maintenance Plan Pursuant to
Section 175A of the CAA
Section 175A of the CAA sets forth the elements of a maintenance
plan for areas seeking redesignation from nonattainment to attainment.
The plan must demonstrate continued attainment of the applicable NAAQS
for at least ten years after the Administrator approves a redesignation
to attainment. Eight years after the redesignation, the state must
submit a revised maintenance plan which demonstrates attainment for the
ten years following the initial ten-year period. To provide for the
possibility of future NAAQS violations, the maintenance plan must
contain contingency measures, with a schedule for implementation,
adequate to assure prompt correction of any air quality problems.
EPA is approving the State of North Carolina's maintenance plan for
the Charlotte-Gastonia nonattainment area
[[Page 34861]]
because EPA finds that the State's submittal meets the requirements of
section 175A.
A. Emissions Inventory
a. Base Year Inventory
On November 13, 1992, the State of North Carolina submitted
comprehensive inventories of VOC, NOX, and carbon monoxide (CO)
emissions from the Charlotte-Gastonia nonattainment area. The inventory
included biogenic, area, stationary, and mobile sources for 1990.
The State of North Carolina submittal contains the detailed
inventory data and summaries by county and source category. Finally,
this inventory was prepared in accordance with EPA guidance. This
action approves the final base year inventory for the Charlotte-
Gastonia area. A summary of the base year inventory is included in the
table below.
1990 Charlotte/Gastonia Typical Summer Day Emissions Tons per Day (TPD)
------------------------------------------------------------------------
Category NOX VOC CO
------------------------------------------------------------------------
Point........................................ 31.25 33.99 35.27
Area......................................... 4.92 67.59 25.00
Non-road..................................... 15.52 19.38 138.45
Biogenic..................................... 2.78 54.41 0
Mobile....................................... 61.64 50.81 371.26
--------------------------
Total...................................... 116.11 226.18 569.98
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b. Emission Budget for Conformity
EPA's transportation conformity regulation requires that states
adopt an emissions budget for conformity for ozone precursors in
maintenance areas. Therefore, the State of North Carolina has adopted
the following emissions budget:
Conformity Emissions Budget
------------------------------------------------------------------------
1999 NOX 1999 VOC 2005 NOX 2005 VOC
Source cat. and county (TPD) (TPD) (TPD) (TPD)
------------------------------------------------------------------------
Mobile:
Mecklenburg............. 33.5 25.5 33.0 25.9
Gaston.................. 9.3 6.3 8.7 5.7
Point:
Mecklenburg............. 2.6 23.0 2.8 24.3
Gaston.................. 79.5 7.3 79.7 7.5
Area:
Mecklenburg............. 3.7 23.0 3.9 33.3
Gaston.................. 1.3 16.7 1.4 16.5
Non-road:
Mecklenburg............. 18.6 20.2 17.8 22.5
Gaston.................. 4.8 5.6 4.1 5.8
------------------------------------------------------------------------
EPA will be taking separate rulemaking action on conformity
emission budgets.
B. Demonstration of Maintenance--Urban Airshed Modeling
a. Control Strategy
The plan must demonstrate maintenance for at least 10 years. The
North Carolina plan demonstrates maintenance out to the year 2005
through the use of the Urban Airshed Model (UAM). On December 16, 1994
and January 6, 1995, the State submitted a revision to the original
maintenance plan submitted to EPA on November 12, 1993, requesting that
EPA parallel process the revisions. These submittals which included
revisions to the modeling pursuant to EPA comment and additional
corrections to the modeling were presented at the public hearing held
in Charlotte on April 19, 1995. The modeling analysis included base and
future case modeling completed according to guidelines presented in the
EPA document ``Guideline for Regulatory Application of the Urban
Airshed Model.'' The future case modeling includes the interim year
1999 and the 10 year maintenance year of 2005. This modeling analysis
did not assume any benefit from the NSR program.
Modeling for all three episodes predicted a small number of grid
cells (< 1="" %)="" above="" .124="" parts="" per="" million="" (ppm)="" for="" both="" 1999="" and="" 2005,="" with="" the="" maximum="" level="" predicted="" of="" .129="" ppm.="" the="" analysis="" of="" control="" options="" showed="" that="">X controls would be more effective
in the maintenance of the standard in the Charlotte/Gastonia area, and,
hence, the State originally selected a strategy that consisted
primarily of additional controls of NOX emissions. The selected
control strategy included the following measures:
Reformulated Gasoline to meet the Federal Phase I and
Phase II standards to begin in 1999 in Mecklenburg, Gaston, Union,
Cabarrus, Lincoln, Rowan, and Iredell Counties;
Clean Fuel Fleet Program, including the schedule for
implementation as specified in the CAA for areas classified serious and
above, in the same seven counties previously listed;
Burning bans in the seven counties for the months of June,
July, and August;
Control of NOX for the Transcontinental Natural Gas
Pumping Station in Iredell County for the months of June, July, and
August; and
Additional 10 percent control beyond the control being
applied to meet title IV NOX requirements on Duke Power's Allen
and Riverbend facilities in Gaston County for the months of June, July,
and August.
The State also took comment at the public hearing on the
feasibility of substituting an enhanced I/M program for the
reformulated gasoline measure. The modeling results indicate that such
substitution would show maintenance of the standard. After
consideration of the comments at the public hearing, the North Carolina
Environmental Management Commission adopted the maintenance plan
without additional controls on May 11, 1995.
2. Request for Comments
As requested by the State, EPA is parallel processing the request
and therefore published a document on April 17, 1995, proposing
approval of the maintenance plan and redesignation request and
soliciting comment on the following control scenarios:
[[Page 34862]]
a. Adoption and implementation in 1999 of the five measures as
detailed above;
b. Adoption and implementation in 1999 of the five measures as
detailed above with enhanced I/M substituted for the reformulated
gasoline program;
c. Adoption and implementation in 1999 of the aforementioned
controls on the Transcontinental Natural Gas Pumping Station in Iredell
County and the additional 10 percent control beyond the title IV
requirements on Duke Power's Allen and Riverbend facilities in Gaston
County; or
d. Approval of the request as demonstrating maintenance with no
additional VOC or NOX controls.
EPA received a number of comments on the proposal and the control
scenarios. Those comments and the response thereto are summarized
below.
Comment #1--Rather than controlling emissions, the plan allows an
increase in NOX emissions of 25 tons per day by 1999 in the
nonattainment area and additional increases throughout the modeling
domain.
Response--Section 175A of the CAA requires that a plan showing
maintenance of the applicable NAAQS for 10 years after redesignation be
incorporated as revision to the SIP. In a September 4, 1992, memorandum
from John Calcagni, Director, Air Quality Management Division, EPA
issued guidance on the requirements for redesignation of areas from
nonattainment to attainment. That guidance contains two primary methods
a state may use to demonstrate maintenance of the O3 NAAQS for an
area. The first method is an emissions inventory demonstration which
includes emission projections showing no increases in emissions of
O3 precursors, i.e., NOX and VOC, in the designated
nonattainment area throughout the 10 year maintenance period. This
method would not allow the projected increase in emissions of NOX
in the nonattainment counties. The second method is a modeling
demonstration showing that the projected levels of emissions of O3
precursors would not cause a violation of the NAAQS. The guidance
further stipulates that the level of modeling required must be at least
that required by the CAA for an attainment demonstration for the area.
Since the Charlotte-Gastonia area is a moderate intra-state area, the
level of modeling required would have been EKMA or its equivalent.
However, the State of North Carolina chose to use the UAM model which
is required for inter-state moderate areas as well as serious and above
areas.
For the reasons explained in the proposal and in the responses to
comments on the modeling provided below, EPA believes that the modeling
demonstration, which evaluated a strategy with a combination of
decreases in VOC emissions and increases in NOX emissions,
submitted by the State of North Carolina adequately demonstrated
maintenance of the NAAQS notwithstanding the projected increase in
NOX emissions. Therefore, EPA believes that the increases in
NOX emissions are permissible.
Comment #2--Concern was expressed regarding the emission increases
projected for Duke Power sources located in the area. It was suggested
that for equity, Duke Power should be required or provided incentives
to install additional emission controls.
Response--The Duke Power plants in question are subject to EPA's
acid rain provisions and reductions in NOX emissions will be
obtained from this program. Neither the CAA nor the EPA require a
specific set of measures to ensure maintenance of the O3 NAAQS,
but rather the state determines for each area what additional
reductions, if any, are necessary. The EPA then determines the adequacy
of the plan. EPA has determined, as explained elsewhere, in this
document and the proposal, that the existing control system is adequate
to ensure maintenance of the NAAQS for ten years.
Comment #3--North Carolina has consistently stated that additional
controls are necessary to maintain the standard and that controls on
sources of NOX emissions are the most effective.
Response--The State's assertion that additional NOX controls
would be necessary to maintain the NAAQS after 1999 was based on the
UAM modeling and the view that every grid cell must be below the
standard in order to demonstrate maintenance. However, EPA has
determined, as discussed in the proposal and elsewhere in this
document, that the State's modeling demonstration adequately
demonstrates maintenance of the NAAQS without additional control
measures.
Comment #4--Monitored daily maximum ozone concentrations over the
last five years indicate that the nonattainment area has been on the
verge of violating the O3 NAAQS. Furthermore, the modeling
predicts future exceedances of the NAAQS for all three episodes.
Response--Although two monitors in the ozone nonattainment area and
one monitor in an adjacent county recorded two exceedances of the
O3 NAAQS in 1993, there have been no violations of the NAAQS in
the last five years. Furthermore, there were no exceedances recorded at
any monitor in the area in 1992 or 1994. An area is allowed one
exceedance of the NAAQS per year with a three year average used to
determine attainment/nonattainment status. Therefore, since the
expected exceedance rate for the area is 0.67 which is less than 1.1
and since all monitors are currently monitoring attainment of the
NAAQS, EPA believes that the monitoring data is sufficient to support
redesignation of the area to attainment. EPA's Response to the comments
regarding the modeling is contained in EPA's Response to Comment #5.
Comment #5--One Commenter provided detailed Comments individually
on each of the six items listed in the proposal as support for EPA's
determination that the modeling demonstration is sufficiently
conservative for EPA to conclude that the NAAQS can be maintained
without additional emission controls. In the proposal, EPA explained
that while its modeling guidance generally requires that modeling
results show attainment of the standard in all grid cells, it does
allow alternative methods for demonstrating attainment on a case-by-
case basis. EPA went on to explain its belief that North Carolina's
modeling for the Charlotte-Gastonia area was sufficiently conservative
to provide an adequate demonstration of maintenance without the
adoption of additional controls notwithstanding the model's prediction
of slight exceedances of the standard in a few grid cells. That belief
was based on the combination of the following six factors:
(1) North Carolina has five years of air quality data showing
attainment of the standard.
(2) The maintenance plan contains pre-adopted measures and a
violation would trigger reduction in emissions by the following O3
season.
(3) The O3 standard is a statistically based NAAQS that allows
one exceedance per year.
(4) North Carolina has done extensive modeling to gain an
understanding of the creation of O3 in the Charlotte area and has
generally made conservative assumptions in selecting modeling inputs.
(5) The uncertainties in the biogenic emission inventory and other
modeling inputs are well within the range of the 2-3 ppb needed to
reach the .124 ppm in all grid cells.
(6) The modeling did not account for lower VOC, NOX and
O3 boundary conditions expected when SIP attainment and title IV
(acid rain program) control programs have been
[[Page 34863]]
implemented in many areas throughout the United States.
This commenter took issue with each of the six factors that EPA
referenced in the proposal.
Response--Before responding to the comments on each of the six
factors individually, EPA notes that, as indicated in the proposal, it
was the combination of factors--not necessarily any particular factor
standing alone--that supports EPA's determination that the modeling
provides an adequate demonstration that the ozone NAAQS will be
maintained in the absence of the adoption of additional control
measures. Furthermore, as explained below, the Comments made with
respect to each of the factors individually fail to undermine the
validity of EPA's conclusion that the modeling provides an adequate
demonstration of maintenance. Although the commenter made relevant
points, EPA believes that when considered together, on balance the
factors support the conclusion that North Carolina has adequately
demonstrated that the Charlotte-Gastonia area will maintain the
standard.
(1) North Carolina has five years of air quality data showing
attainment of the standard.
With three years of air quality showing attainment an area can
request redesignation. North Carolina's request is strengthened by the
fact that it has five years of air quality data showing no violations
of the O3 NAAQS.
Based upon a trend analysis performed by EPA, meteorologically
adjusted O3 trends in Charlotte (and surrounding areas) have shown
a modest but consistent improvement of approximately 1 percent per year
between 1983 and 1993. However, the most recent five years analyzed
(1988-1993) have shown an accelerated rate of improvement of
approximately 2 to 3 percent per year (10 percent over the five year
period) suggesting that recent ozone air quality is improving when
meteorological conditions are eliminated.
Moreover, EPA has conducted an analysis of the O3 potential in
the major urban areas, including Charlotte, using available
meteorological data collected over the past 41 years. The study
(currently undergoing review for publication in Atmospheric
Environment), indicates that meteorological conditions favoring high
O3 ranked the summer of 1993 as the 2nd most severe O3 year
in the past 41 years. The two years, 1988 and 1987 were ranked 7th and
4th, respectively. The meteorology for all three years was very
conducive to producing high O3 concentrations. Since North
Carolina did not have a violation in 1993 under meteorological
conditions of comparable severity to the 1988 and 1987 modeling
analyses, this supports the redesignation demonstration.
Although NOX emissions are projected to increase over the
maintenance period, i.e. from the 1990 base line inventory, the State
of North Carolina's experience in other similar areas (Raleigh/Durham
and Greensboro/Winston-Salem) suggests that total NOX emissions in
1999 will be less than 1993. Specifically, the projected emissions from
the three area power plants in 1999 that are the area's primary
NOX sources are less than the actual emissions from those plants
in 1993. Since the area was able to maintain the standard despite the
higher NOX emissions and adverse meteorological conditions in
1993, it would be expected that the projected decrease in power plant
emissions would support the ability for the area to continue to
maintain the O3 NAAQS.
(2) The maintenance plan contains pre-adopted measures and a
violation would trigger reduction in emissions by the following ozone
season. While it is true that the presence of pre-adopted measures in
the maintenance plan triggered by a violation does not make the
modeling analysis conservative, it does add strength to the package as
a whole and will allow the State to implement new controls to quickly
address any future nonattainment problem. The State has done
preliminary modeling analysis on both the pre-adopted and the other
contingency measures listed in the plan which will assist the State in
timely implementation of the most effective measures.
Additionally, the contingency plan contains a secondary trigger
which is an exceedance of the ozone standard that would indicate a
violation could be imminent. This trigger will be activated within 30
days of the State finding the exceedance. Once the secondary trigger is
activated, the State Air Quality Section will commence analysis,
including updated modeling as necessary, to determine what control
measures will be required to keep the area in attainment, with the
regulatory adoption process for any necessary measures beginning by May
1 of the following year. As the contingency measures based on the
secondary trigger should help the area stay in attainment, those
measures should also help the area maintain the standard and do provide
an additional level of assurance that the area will maintain the
standard.
(3) The O3 standard is a statistically based NAAQS that allows
one exceedance per year.
Developing an attainment test using gridded concentrations for a
few selected days to match a NAAQS determination which uses sparsely
located monitors for a complete hourly O3 season is not simple.
Recognizing the severity of O3 forming potential for selected
episodes, as well as the NAAQS allowing one exceedance at each monitor
location over a three year period, led EPA to consider how stringent
the model test of requiring every grid cell modeled across the domain
to be below 124 ppb for all hours might be. Again, based on the
severity of the years modeled, EPA believes the modeling demonstration
indicates that a few grid cells would exceed 124 ppb by a slight amount
(less than 1% with a maximum value of 129 ppb) is within a margin of
safety that the NAAQS will be maintained provided the contingency
measures in the plan are identified and implemented, if the need is
indicated by monitored data. As indicated previously, the State's plan
contains a secondary trigger for contingency measures based on an
exceedance of the O3 NAAQS that would indicate a violation is
imminent.
(4) North Carolina has done extensive modeling to gain an
understanding of the creation of O3 in the Charlotte area and has
generally made conservative assumptions in selecting modeling inputs.
EPA recognizes and allows for uncertainty in model estimates as
part of the model performance evaluation conducted prior to use in
strategy development. EPA guidance includes recommended ranges for
statistical performance measures. For the North Carolina application,
although model estimates were sometimes below the observed highest
concentrations (base case), overall the performance results suggest
that UAM is unbiased and is therefore expected to produce unbiased
estimates of future air quality assuming unbiased (non-conservative)
estimates of future emissions and boundary conditions are used.
In fact, North Carolina was conservative in its choice of model,
years to simulate, boundary conditions and emissions growth factors.
Although, North Carolina was not required to do so, it chose to use UAM
so as to better understand and quantify the effect of ozone precursors
in the area and thus identify the most cost effective strategy for
maintaining the NAAQS. EPA believes North Carolina did select years
that are conducive to high levels of O3 (also see discussion
above) and chose
[[Page 34864]]
episodes for which some of the highest O3 levels were observed in
the area. North Carolina used boundary concentrations along the North
Carolina domain that were only reduced by 5 percent (O3, NOX,
and VOC) so that the maximum level of ozone was 120 ppb for the July
1988 northerly transport episode. It is quite likely that the combined
effect of VOC/NOX controls throughout the eastern U.S. will result
in O3 boundary levels that are below those used in this modeling
exercise. Finally, North Carolina used the 1990 BEA growth factors to
project emissions. These factors were derived before the CAA mandated
controls were implemented and do not take into consideration changes in
business behavior that has occurred as companies have applied
expenditures towards control measures rather than expansion. Also, the
6 year window, 1988-93, used to estimate VMT growth includes very high
growth years and the area is not expected to continue to grow at that
rate. If the State had elected to use lower boundary conditions and
lower growth rates, as allowed by EPA guidelines, it is likely that the
modeling would have predicted ozone levels of 124 ppb or below in all
grid cells.
(5) The uncertainties in the biogenic emissions inventory and other
modeling inputs are well within the range of the 2-5 ppb needed to
reach 124 ppb in all grid cells.
(The sentence above, as included in the proposal document,
contained a typographical error, as it read ``* * * the range of the 2-
3 ppb * * *.'')
As discussed in the response to item (4) above, North Carolina made
very conservative assumptions on model inputs for the NC application
which are within the 2-5 ppb reductions needed to reach 124 ppb. Based
on EPA guidance, North Carolina used the most current and only
regulatory version of the biogenic model available to states at the
time of its modeling analyses. The new version of the biogenic model,
BEIS2, is just now being released for use by states. The impact of the
new model on O3 predictions is still being evaluated. The State of
North Carolina has a commitment to perform modeling analyses in the
future and will use the most current methodologies for all modeling
inputs including BEIS as well as the most current model.
(6) The modeling did not account for lower VOC, NOX and
O3 boundary conditions expected when SIP attainment control
programs have been implemented in many areas through the United States.
Contrary to the assertions of the commenter, boundary conditions
are relevant to modeling episodes for Charlotte. North Carolina modeled
two transport episodes and one stagnation episode. As indicated above,
conservative assumptions on boundary conditions were made for the July
1988 transport episode. The boundary conditions for the other two
episodes, including the stagnation episode, were not reduced. As states
and the Environmental Council of States (ECOS) embark on the Phase II
modeling efforts, North Carolina is within the regional domain being
evaluated. If regional or more local controls appear warranted based on
new analysis, North Carolina will be notified and EPA is confident that
the State will work with EPA (using better information as it becomes
available) to make any adjustment needed to maintain the NAAQS in the
Charlotte area.
Comment #6--The maintenance plan was developed without regard for
the potential effects on the Southern Appalachian Mountains despite
North Carolina's commitment to the Southern Appalachian Mountain
Initiative (SAMI).
Response--The Charlotte-Gastonia modeling analysis was not
specifically designed to evaluate the effects of the plan on the
Southern Appalachian Mountains. Only the O3 inputs in the
Charlotte-Gastonia airshed were required for analysis of the
redesignation of the Charlotte-Gastonia area. The meteorological
episodes modeled for the redesignation request, while significant for
O3 formation in the Charlotte-Gastonia area, do not include a
situation where emissions from the Charlotte-Gastonia area are
transported into the mountain region, which is currently in attainment
and is not adjacent to the Charlotte-Gastonia area. Additionally,
approval of this maintenance plan and redesignation request does not
preclude additional controls being required on the sources in the
Charlotte-Gastonia area as a result of future analysis indicating that
such controls are necessary to protect air quality in the mountain
region. In the event such controls are found to be necessary, EPA has
the authority under section 110(b)(2) to require the adoption of
control measures if the State fails to do so.
Comment #7--There were several comments regarding the proposal by
the State to require Phase II reformulated gasoline (RFG) in a seven
county area beginning in 1999. The commenters noted that since the CAA
requires Phase II RFG in some areas beginning in 2000, that the fuel
may not be available in 1999. Furthermore, several commenters indicated
their belief that an enhanced I/M program would be of greater benefit
at a lower cost in controlling ozone.
Response--As the maintenance plan approved by EPA in this final
action does not include either Phase II RFG or enhanced I/M as a
measure for maintenance of the NAAQS, issues regarding the use of Phase
II RFG or enhanced I/M as maintenance measures are no longer pertinent.
Comment #8--It was commented that the contingency plan should not
include a list of specific options in the maintenance plan and that
contingency measures should not be pre-adopted.
Response--While the commenter is correct that contingency measures
do not have to be pre-adopted, a state may chose whether or not to pre-
adopt any or all of the listed contingency measures. However, EPA
policy does require that the maintenance plan include a list of
possible contingency measures and a schedule for implementing those
measures that are determined to be necessary to ensure continued
maintenance of the NAAQS. EPA's policy is based on section 175A, which
requires that maintenance plans ``contain such contingency provisions
as the Administrator deems necessary to assure that the state will
promptly correct any violation of the standard which occurs after''
redesignation. In any event, the State did not include additional pre-
adopted measures in the final submittal.
Comment #9--The secondary trigger should be eliminated because it
is vague and would raise questions about federal enforceability.
Additionally, one commenter believes interpretation that an exceedance
of the NAAQS should cause a contingency measure to be adopted is too
stringent.
Response--While EPA policy and section 175A require only that a
maintenance plan contain contingency measures triggered by a violation
of a NAAQS, EPA has encouraged states to select triggers based on
events short of a violation in order to prevent violations from
occurring so that the area continues to maintain the NAAQS or to bring
the area back into attainment more quickly should a violation occur
after the trigger event has occurred. For example, the September 4,
1992, memorandum from John Calcagni suggests that states use indicators
such as monitoring, modeling and inventory levels to identify when
early action may prevent a violation.
The secondary trigger in the Charlotte-Gastonia maintenance plan is
used as an alert for the State that action may be needed to ensure
continued maintenance of the NAAQS. The resulting analysis may or may
not
[[Page 34865]]
indicate additional controls are needed. This mechanism is perfectly
consistent with the purpose of a maintenance plan which is to ensure
continued maintenance of the NAAQS. EPA believes that the use of the
secondary trigger will help North Carolina not only to bring the area
back into attainment quickly but to also prevent violations from
occurring.
EPA does not believe the use of an exceedance of the NAAQS as an
indicator which may lead to additional controls causes an enforcement
problem. Under 40 CFR 51.110, states are required to develop control
strategies for the attainment and maintenance of NAAQS. These
strategies must provide for both the attainment of the standards in
nonattainment areas and the maintenance of those standards in
attainment areas. Since NOX and VOC are defined as precursors to
O3, a criteria pollutant for which there is a NAAQS, emission
reductions of NOX and/or VOC are federally enforceable in
attainment areas provided they are part of the federally-approved SIP.
As the CAA requires SIPs for areas redesignated to attainment to
include measures necessary to maintain the NAAQS, emission reductions
required for maintenance of the standard in the future would be
federally enforceable.
Comment #10--If contingency measures are triggered in the near-term
(i.e., before 2003), additional modeling should not be required unless
there has been a significant change in the model inputs and
assumptions.
Response--North Carolina's contingency plan states that additional
analysis will be done if necessary. Therefore, such analysis is not
required, but is within the State's discretion to do if there have been
significant changes in model inputs and assumptions or control
technology to warrant a new analysis. EPA believes the contingency plan
is approvable as written as it provides adequate assurance that
violations will be corrected promptly in accordance with section 175A.
Comment #11--The contingency options from which the State could
choose should continue to include RFG or enhanced I/M, clean fuel fleet
provisions, open burning restrictions, summer NOX controls from
Transcontinental Gas Pipe Line Corporation and 10% beyond title IV from
Duke Power's Riverbend and Allen plants during the summer. In addition,
NOX and possibly VOC RACT should be available as contingency
measures.
Response--The final submittal from the State includes in their list
of possible contingency measures additional NOX and VOC RACT or
greater controls on sources, particularly Duke Power and
Transcontinental Gas Pipe Line Corporation, Stage II vapor control,
RFG, enhancements to the I/M program, clean fuel fleets and any other
measures that may be appropriate and feasible. The State also indicated
it intends to develop an economic incentive program that would provide
incentives to sources that purchase clean alternative vehicles.
Although the State could not adopt RFG rules without receiving a
section 211(c)(1) waiver of preemption from EPA, EPA believes that
North Carolina has identified an adequate and appropriate list of
contingency measures in light of the numerous measures it has listed.
Comment #12--The time schedule provisions of section 181(b) of the
CAA are equally applicable to stationary and mobile sources. If
contingency measures are needed in the future, the time schedules of
the CAA should not be preferentially offered to mobile sources unless
stationary sources have the same option.
Response--Stationary source controls can often be implemented on a
faster time frame than mobile source controls. It is generally clear
what sources are subject to such rules and what is required for a
source to comply. Mobile source measures are more difficult to develop
and implement as there is a greater need for public education on mobile
related programs. They also often take more time to implement. One of
the primary considerations for choosing a contingency measure to
implement is the time needed to develop, adopt and implement the
measures necessary to prevent or correct a NAAQS violation. If the
analysis shows that stationary sources play an important role in such a
strategy, then implementation should be achieved as soon as possible.
Comment #13--The contingency plan should provide the State with the
flexibility to implement all, or any subset, of the above contingency
measures as a first round of controls, if needed. However, once one of
the contingency measures has been chosen and activated from the above
list, no additional controls would be imposed on that category of
sources until the other first round contingency control options have
been activated. If a second round is required, than modeling should be
used to develop a new balanced and cost-effective strategy.
Response--The primary purpose of the contingency plan is to bring
an area back into attainment should the area violate the NAAQS after
redesignation. The choice of which measures to implement lies with the
state so long as the measures from which the state is choosing are
effective. The North Carolina contingency plan provides the State with
adequate flexibility to enact the measures which will be most effective
in returning the area to attainment.
C. Verification of Continued Attainment
Continued attainment of the O3 NAAQS in the nonattainment area
depends, in part, on the State of North Carolina's efforts toward
tracking indicators of continued attainment during the maintenance
period. The primary trigger of the contingency plan will be a violation
of the ambient air quality standard for ozone. The trigger date will be
the date that the State certifies to EPA that the data is quality
assured, which will occur no later than 30 days after the recorded
violation. The secondary trigger of the contingency plan will be an
exceedance of the ozone standard that would indicate a violation could
be imminent. This trigger will be activated within 30 days of the State
finding the exceedance.
Once either the primary or the secondary trigger is activated, the
State Air Quality Section will commence analysis, including updated
modeling as necessary, to determine what control measures will be
required to bring the area back into attainment. By May 1 of the year
following the ozone season in which the primary trigger has been
activated, the State will complete the analysis and adopt stationary
control measures indicated by the analysis, using the emergency rule
process as necessary. The time frame for adopting measures other than
for stationary sources will be based on the time frames in section
181(b) of the CAA. Where only the secondary trigger has been activated,
the State will complete the analysis and begin the regulatory adoption
process for any measures that are needed by May 1 of the following
year.
D. Contingency Plan
The level of VOC and NOX emissions in the nonattainment area
will largely determine its ability to stay in compliance with the
O3 NAAQS in the future. Despite the State's best efforts to
demonstrate continued compliance with the NAAQS, the ambient air
pollutant concentrations may exceed or violate the NAAQS. Therefore,
the State of North Carolina has provided contingency measures with a
schedule for implementation in the event of a future O3 air
quality problem. The actual measures will be determined from the
analysis process described in
[[Page 34866]]
the Verification of Continued Attainment portion of this document. The
measures analyzed will include RACT or greater level control for
NOX and VOC sources, particularly Duke Power and Transcontinental
Gas Pipe Line Corporation, Stage II vapor control for gasoline
dispensing facilities, RFG, enhancements to the I/M program, clean fuel
fleet program, transportation control measures, and any other
appropriate and feasible measures. EPA finds that the contingency plan
provided in the State of North Carolina's submittal meets the
requirements of section 175A(d) of the CAA.
E. Subsequent Maintenance Plan Revisions
In accordance with section 175A(b) of the CAA, the State of North
Carolina has agreed to submit a revised maintenance SIP eight years
after the nonattainment area is redesignated to attainment. Such
revised SIP will provide for maintenance for an additional ten years.
Additionally, the State has indicated that should analysis of the
current pre-adopted RACT contingency measures demonstrate that they
will not be the most effective in bringing the area back into
attainment, they may revise these pre-adopted measures in the future.
Furthermore, based on updated analysis, the State has indicated they
may periodically revise the contingency plan. All such revisions will
be subject to full public participation in the regulatory adoption
process.
Final Action
EPA approves the State of North Carolina's request to redesignate
to attainment the Charlotte-Gastonia O3 nonattainment area and
maintenance plan. As discussed above, the emission statement, RACT
catch-ups, and I/M requirements have been approved. EPA also approves
the 1990 baseyear inventory for the Charlotte-Gastonia nonattainment
area.
EPA finds that there is good cause for this redesignation to become
effective immediately upon publication because a delayed effective date
is unnecessary due to the nature of a redesignation to attainment,
which exempts the area from certain Clean Air Act requirements that
would otherwise apply to it. The immediate effective date for this
redesignation is authorized under both 5 U.S.C. section 553(d)(1),
which provides that rulemaking actions may become effective less than
30 days after publication if the rule ``grants or recognizes an
exemption or relieves a restriction'' and section (d)(3), which allows
an effective date less than 30 days after publication ``as otherwise
provided by the agency for good cause found and published with the
rule.''
Under section 307(b)(1) of the Act, 42 U.S.C. 7607(b)(1), petitions
for judicial review of this action must be filed in the United States
Court of Appeals for the appropriate circuit by September 5, 1995.
Filing a petition for reconsideration by the Administrator of this
final rule does not affect the finality of this rule for purposes of
judicial review nor does it extend the time within which a petition for
judicial review may be filed, and shall not postpone the effectiveness
of such rule or action. This action may not be challenged later in
proceedings to enforce its requirements. (See section 307(b)(2) of the
Act, 42 U.S.C. 7607(b)(2).)
The OMB has exempted these actions from review under Executive
Order 12866.
Nothing in this action shall be construed as permitting or allowing
or establishing a precedent for any future request for a revision to
any state implementation plan. Each request for revision to the state
implementation plan shall be considered separately in light of specific
technical, economic, and environmental factors and in relation to
relevant statutory and regulatory requirements.
Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA
must prepare a regulatory flexibility analysis assessing the impact of
any proposed or final rule on small entities. 5 U.S.C. 603 and 604.
Alternatively, EPA may certify that the rule will not have a
significant impact on a substantial number of small entities. Small
entities include small businesses, small not-for-profit enterprises,
and government entities with jurisdiction over populations of less than
50,000.
Redesignation of an area to attainment under section 107(d)(3)(E)
of the CAA does not impose any new requirements on small entities.
Redesignation is an action that affects the status of a geographical
area and does not impose any regulatory requirements on sources. The
Administrator certifies that the approval of the redesignation request
will not affect a substantial number of small entities.
Unfunded Mandates
Under Sections 202, 203, and 205 of the Unfunded Mandates Reform
Act of 1995 (``Unfunded Mandates Act''), signed into law on March 22,
1995, EPA must undertake various actions in association with proposed
or final rules that include a Federal mandate that may result in
estimated costs of $100 million or more to the private sector, or to
State, local, or tribal governments in the aggregate.
Through submission of this state implementation plan or plan
revision, the State and any affected local or tribal governments have
elected to adopt the program provided for under section 175(A) and
section 187(a)(1) of the Clean Air Act. These rules may bind State,
local and tribal governments to perform certain actions and also
require the private sector to perform certain duties. To the extent
that the rules being approved by this action will impose no new
requirements; such sources are already subject to these regulations
under State law. Accordingly, no additional costs to State, local, or
tribal governments, or to the private sector, result from this action.
EPA has also determined that this final action does not include a
mandate that may result in estimated costs of $100 million or more to
State, local, or tribal governments in the aggregate or to the private
sector.
List of Subjects
40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide,
Hydrocarbons, Incorporation by reference, Intergovernmental relations,
Nitrogen dioxide, Ozone, Reporting and recordkeeping requirements.
40 CFR Part 81
Air pollution control, National parks, Wilderness areas.
Dated: June 19, 1995.
Patrick M. Tobin,
Acting Regional Administrator.
Chapter I, title 40, Code of Federal Regulations, is amended as
follows:
PART 52--[AMENDED]
1. The authority citation for part 52 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.
Subpart II--North Carolina
2. Section 52.1770 is amended by adding paragraph (c)(83) to read
as follows:
Sec. 52.1770 Identification of plan.
* * * * *
(c) * * *
(83) The maintenance plan and redesignation request for the
Charlotte-Gastonia area which include Mecklenburg and Gaston Counties
submitted by the State of North Carolina on November 12, 1993.
(i) Incorporation by reference.
(A) The following subsections of Section 3.0, entitled Maintenance
Plan,
[[Page 34867]]
in the Supplement To The Redesignation Demonstration and Maintenance
Plan for the Charlotte/Gaston Ozone Nonattainment Area adopted by the
North Carolina Environmental Management Commission on May 11, 1995: 3.1
Concept of North Carolina's Maintenance Plan; 3.2 Foundation Control
Program; Table 3.2 of Subsection 3.3; and 3.4 Contingency Plan.
(ii) Other material. None.
PART 81--[AMENDED]
1. The authority citation for part 81 continues to read as follows:
Authority: 42.U.S.C. 7401-7671q.
2. In Sec. 81.334, the ozone table is amended by removing the
Charlotte-Gastonia area and its entries in the first alphabetical list
and by adding in alphabetical order entries for ``Gaston County'' and
``Mecklenburg County'' to the second listing of counties to read as
follows:
Sec. 81.334 North Carolina.
* * * * *
North Carolina--Ozone
----------------------------------------------------------------------------------------------------------------
Designation Classification
-------------------------------------------------------------------------------
Date\1\ Type Date\1\ Type
----------------------------------------------------------------------------------------------------------------
Rest of State................... ........................... Unclassifiable/Attainment.. ......... .........
* * * * * *
*
Gaston County................... July 5, 1995...............
* * * * * *
*
Mecklenburg County.............. July 5, 1995...............
* * * * * *
*
----------------------------------------------------------------------------------------------------------------
\1\This date is November 15, 1990, unless otherwise noted.
* * * * *
[FR Doc. 95-16358 Filed 7-3-95; 8:45 am]
BILLING CODE 6560-50-P
