Federal Register: August 3, 2001 (Volume 66, Number 150)
DOCID: FR Doc 01-19151
ENVIRONMENTAL PROTECTION AGENCY
CFR Citation: 40 CFR Part 52
IN ID: [IN136-1; FRL-7022-4]
NOTICE: Part II
DOCUMENT ACTION: Proposed rule.
Approval and Promulgation of Implementation Plans; Indiana; Ozone
DATES: Written comments must be received on or before September 4, 2001.
EPA proposes to approve the following as revisions to the
Indiana State Implementation Plan (SIP) for the ChicagoGaryLake
County ozone nonattainment area, i.e., for the Indiana portion of this
bistate ozone nonattainment area: An ozone attainment demonstration; a
post1999 ozone RateOfProgress (ROP) plan; a contingency measures
plan for both the ozone attainment demonstration and the post1999 ROP
plan; a commitment to conduct a midcourse review of the ozone
attainment demonstration; motor vehicle conformity emission budgets for Volatile Organic Compounds (VOC) and Oxides of Nitrogen (
See Alcohol, Tobacco and Firearms Bureau; See Customs Service; See Internal Revenue Service; Environmental Protection Agency,
Throughout this document whenever ``we,'' ``us,'' or ``our'' is used, we mean EPA. Whenever ``you'' or ``me'' is used, we mean you the reader of this proposed rule or the sources subject to the requirements of the State as discussed in the State's submittal or in this proposed rule.
This section provides additional information by addressing the following topics and questions:
I. What Action is EPA Proposing Today?
II. Background Information
A. What is a State Implementation Plan (SIP)?
B. What is the Federal Approval Process for a SIP?
C. What Does Federal Approval of a State Regulation Mean?
D. What are EPA's Options for Action on a State SIP Submittal?
E. What Ozone Nonattainment Area is Addressed by the State Submittal Reviewed in This Proposed Rule?
F. What Prior EPA Rulemakings Relate to or Led to the State Submittal Reviewed in This Proposed Rule?
G. What is the Time Frame for EPA to Take Action on the State Submittal?
H. What are the Basic Components of the State Submittal and What are the Subjects Covered in this Proposed Rule?
III. Ozone Attainment Demonstration and Emissions Control Strategy
A. Background Information and Requirements Placed on the Ozone Attainment Demonstration
1. What Clean Air Act requirements apply to the State's ozone attainment demonstration?
2. What is the history of the State's ozone attainment
demonstration and how is it related to EPA's NO
3. What are the modeling requirements for the ozone attainment demonstrations?
4. What additional analyses may be considered when the ozone modeling fails to show attainment of the ozone standard?
5. Besides the modeled attainment demonstration and adopted emission control strategy, what other elements must be addressed in an attainment demonstration SIP?
6. What are the relevant EPA policy and guidance documents?
B. Technical Review of the State's Submittal
1. When was the attainment demonstration addressed in public hearings, and when was the attainment demonstration submitted to the EPA?
2. What are the basic technical components of the submittal?
3. What modeling approach was used in the analyses to develop and validate the ozone modeling system?
4. How were the 1996 base year emissions developed?
5. What procedures and sources of projection data were used to project the emissions to the attainment year?
6. How were the 1996 and 2007 emission estimates quality assured?
7. What is the adopted emissions control strategy?
8. What were the ozone modeling results for the base period and for the future attainment period with the selected emissions control strategy?
9. Do the modeling results demonstrate attainment of the ozone standard?
10. Does the attainment demonstration depend on future reductions of regional emissions?
11. Has the State adopted all of the regulations/rules needed to support the ozone attainment strategy and demonstration?
C. EPA's Evaluation of the Ozone Attainment Demonstration Portion of the State's Submittal
1. Did the State adequately document the techniques and data used to derive the modeling input data and modeling results of the analyses?
2. Did the modeling procedures and input data used comply with the Clean Air Act requirements?
3. Did the State adequately demonstrate attainment of the ozone standard?
4. Has Indiana adequately documented the adopted emissions control strategy?
5. Is the emissions control strategy acceptable? IV. Post1999 RateofProgress (ROP) Plan
A. What is a Post1999 ROP Plan?
B. What is the ROP Contingency Measure Requirement?
C. What Indiana Counties are Covered by the Post1999 ROP Plan?
D. Who is Affected by the Indiana Post1999 ROP Plan?
E. What Criteria Must a Post1999 ROP Plan Meet to be Approved?
F. What Changes Did Indiana Make to the 1990 VOC Base Year Emissions Inventory In This Submission?
G. Why were the 1996 15 Percent ROP Target Level and the 1999 9 Percent ROP Target Level for Lake and Porter
Counties Recalculated, and Does Indiana Have to Revise The Prior ROP Plans?
H. How Were the 1996 and 1999 Target Emission Levels for Lake and Porter Counties Recalculated?
I. How Were the Post1999 Emission Targets and Emission Reduction Requirements Calculated?
J. What are the Criteria for Acceptable ROP Emission Control Strategies?
K. What are the Emission Control Measures In Indiana's Post1999 ROP Plan?
L. Are the Emission Control Measures and Calculated Emission Reductions Acceptable to the EPA?
M. Are the Planned Emissions Reductions Adequate to Meet the ROP Emission Reduction Requirements, Including ROP Contingency Measure Requirements?
N. How Does The ROP Plan Affect Outstanding Plan Requirements for Contingency Measures on the 15 Percent ROP Plan and the Post 1996 9 Percent ROP Plan?
V. Contingency Measures Plan
A. What are the Requirements for Contingency Measures Under Section 172(c)(9) and Section 182(c)(9) of the CAA?
B. How Do the Northwest Indiana Attainment Demonstration and ROP SIP Address the Contingency Measure Requirements?
C. Do the Northwest Indiana Attainment Demonstration and ROP Plans Meet the Contingency Measure Requirements?
VI. MidCourse Review Commitment
A. Did Indiana Submit a MidCourse Review Commitment? VII. NO
A. What is the History of the NO
B. What are the Conclusions of the State Regarding the Impact of
the Ozone Attainment Demonstration on the NO
C. What are the Conclusions That Can Be Drawn Regarding the
D. What are the EPA Conclusions Regarding the Existing
A. What Are the Requirements for Mobile Source Conformity Emissions Budgets?
B. How Were the Indiana Attainment Demonstration and ROP Emissions Budgets Developed?
C. Did Indiana Commit to Revise the Budgets When EPA Releases MOBILE6?
D. Are the Indiana Emissions Budgets Adequate for Conformity Purposes?
IX. Reasonably Available Control Measure (RACM) Analysis
A. What are the Requirements for RACM?
B. How Does This Submission Address the RACM Requirement?
C. Does the Northwest Indiana Attainment Demonstration Meet the RACM Requirement?
X. Administrative Requirements
I. What Action Is EPA Proposing Today?
Based on a review of all available information, Clean Air Act (CAA)
requirements, and relevant EPA guidance, we propose to approve: (1)
Indiana's 1hour ozone attainment demonstration for the ChicagoGary
Lake County ozone nonattainment area; (2) Indiana's post1999 ROP plan
(an ROP plan covering the time period of November 15, 1999 through
November 15, 2007) for the Indiana portion of the ChicagoGaryLake
County ozone nonattainment area (the Northwest Indiana area); (3)
Indiana's contingency measure plans for both the ozone attainment
demonstration and the post1999 ROP plan; (4) Indiana's commitment to
conduct a midcourse review of the ozone attainment demonstration; (5)
Indiana's ROP and attainment motor vehicle conformity emission budgets
for VOC and NO
We propose to modify an existing NO
\1\ It is not clear to what extent the NO
\2\ The additional NO
We propose to modify the existing NO
\3\ States with NO
Finally, we propose to incorporate into the SIP part of an agreed order between U.S. Steel and IDEM signed by IDEM on March 22, 1996. This part (section 3 of Exhibit E, ``Clean Water Coke Quench Project'') of the agreed order requires U.S. Steel to establish a coke plant process water treatment plant at its Gary Works, and results in VOC emissions reductions relied on in the post1999 ROP plan. We are not incorporating the remaining portions of the agreed order into the SIP because the State is not relying on these portions of the agreed order to meet the CAA requirements addressed in this proposed rule. II. Background Information
A. What Is a State Implementation Plan (SIP)?
Section 110 of the CAA requires states to develop air pollution control regulations (rules) and strategies to ensure that state air quality meets the National Ambient Air Quality Standards (NAAQS). Each state must submit the rules and emission control strategies to the EPA for approval and promulgation into a federally enforceable SIP.
Each federally approved SIP protects air quality primarily by addressing air pollution at its points of origin. The SIPs can be and generally are extensive, containing many state rules or other enforceable documents and supporting information, such as emission inventories, monitoring documentation, and modeled attainment demonstrations.
B. What Is the Federal Approval Process for a SIP?
In order for state rules and emission control strategies to be incorporated into the federally enforceable SIPs, states
must formally adopt the rules and emission control strategies consistent with state and federal requirements. This process generally includes public notice, public hearings, public comment periods, and formal adoption by stateauthorized rulemaking bodies.
Once a state rule or emissions control strategy is adopted, the state submits it to us for inclusion into the SIP. We must provide public notice and must seek additional public comment regarding our proposed action on the submission. If we receive adverse comments, we must address them prior to any final federal action (we generally address them in a final rulemaking action).
All state rules and supporting information approved by the EPA under section 110 of the CAA are incorporated into federally approved SIPs. Records of such SIP actions are maintained in the Code of Federal Regulations (CFR) at Title 40, part 52, titled ``Approval and Promulgation of Implementation Plans.'' The actual state rules which are approved are not reproduced in their entirety in the CFR, but are ``incorporated by reference,'' which means that EPA has approved given state rules with specific effective dates, has identified the rules in the CFR, and, thereby, has identified the full texts of the rules by reference.
C. What Does Federal Approval of a State Regulation Mean?
Enforcement of a state rule before and after it is incorporated
into a federally approved SIP is primarily a state responsibility.
After a rule is federally approved, however, section 113 of the CAA
authorizes EPA to conduct enforcement actions against violators.
Citizens are also offered legal recourse to address violations as described in section 304 of the CAA.
D. What Are EPA's Options for Action on a State SIP Submittal?
Depending on the circumstances unique to each of the SIP submissions, we may propose one or more of several types of approval, or disapproval in the alternative (or a combination if our rulemaking process involves separable portions of a SIP submission). In addition, these proposals may identify additional actions that may be necessary for a state to complete before EPA may fully approve the submissions.
The CAA provides for EPA to approve, disapprove, partially approve, or conditionally approve a state's submission. The EPA must fully approve a submission if it meets the requirements of the CAA.
If a submission is deficient in some way, EPA may disapprove the submission. In the alternative, if portions of the submission are approvable, EPA may partially approve and partially disapprove the submission, or may conditionally approve the submission based on a state's commitment to correct the deficiency by a date certain, not later than one year from the date of EPA's final conditional approval.
The EPA recognizes that, in some limited circumstances, it may be
appropriate to issue a full approval for a submission that consists, in
part, of an enforceable commitment by a state. Unlike the commitment
for a submission correction under a conditional approval, such an
enforceable commitment can be enforced in court by EPA or citizens. In
addition, this type of commitment may extend beyond one year following
EPA's final approval action. Thus, EPA may accept such an enforceable
commitment where it is infeasible for the state to accomplish the necessary action(s) in the short term.
E. What Ozone Nonattainment Area Is Addressed by the State Submittal Reviewed in This Proposed Rule?
The December 21, 2000 submittal of IDEM reviewed here primarily
deals with attainment of the 1hour ozone standard in the Northwest
Indiana area (the Indiana portion of the ChicagoGaryLake County ozone
nonattainment area). As noted above, this area includes Lake and Porter
Counties. We are separately rulemaking on the attainment plan for the
Illinois portion of the ChicagoGaryLake County ozone nonattainment area.
F. What Prior EPA Rulemakings Relate to or Led to the State Submittal Reviewed in This Proposed Rule?
On December 16, 1999 (64 FR 70514), the EPA proposed to
conditionally approve the 1hour ozone attainment demonstration for the
Northwest Indiana area submitted by IDEM on April 30, 1998. The April
30, 1998 attainment demonstration submittal was based on a range of
possible emission control measures reflecting various emission control
alternatives, and did not specify a single set of emission control
measures that the State had adopted as an emissions control strategy.
We based our December 16, 1999 proposed conditional approval on the
State's commitment to adopt and submit, by December 31, 2000, a final
ozone attainment demonstration SIP revision and a post1999 ROP plan,
including the necessary Stateadopted air pollution control rules
needed to support and complete the ozone attainment demonstration and
post1999 ROP plan. In the alternative, we proposed to disapprove the
attainment demonstration if, by December 31, 2000, the State did not
adopt an emissions control strategy supported by its modeled ozone
attainment demonstration, and did not submit adequate motor vehicle
emission budgets for VOC and NO
The December 16, 1999 proposed rulemaking noted that, if the EPA
issued a final conditional approval of the State's April 30, 1998
submission \4\, the conditional approval would revert to a disapproval
if the State did not adopt and submit a complete SIP submission with
the following elements by December 31, 2000: (1) A final adopted ozone
modeling analysis that fully assesses the impacts of regional
\4\ To date, the EPA has not issued a final rule conditionally approving the State's April 30, 1998 submittal. As noted in this proposed rule, the State has submitted a revised ozone attainment plan, negating the need for the EPA to complete the conditional approval of the April 30, 1998 submittal.
As noted below, the December 21, 2000 submittal, in part, addresses
a post1999 ROP plan for the Northwest Indiana area. The post1999 ROP
plan provides required emission reductions in addition to Indiana's 15 percent ROP plan (VOC emission reductions
occurring prior to November 15, 1996) and 9 percent post1996 ROP plan (VOC emission reductions occurring prior to November 15, 1999) for this ozone nonattainment area. On July 18, 1997 (62 FR 38457), we published a final rule approving Indiana's 15 percent ROP plan. On January 26, 2000 (65 FR 4126), we published a final rule approving Indiana's post 1996 ROP plan. These final rules addressed the emission control measures selected by the State to achieve required ROP emission reductions, and addressed the State's calculation of the 1996 and 1999 VOC emission targets for the Northwest Indiana area.
The December 21, 2000 submittal includes, as part of the ozone attainment demonstration, the modeled impacts of regional
Since EPA waived the NO
\6\ Statewide NO
G. What Is the Time Frame for EPA To Take Action on the State Submittal?
As noted above, the EPA is providing a 30day public comment period
for this proposed rule. This comment period is typical for such
proposed rules and is critical in this case given the relatively tight
time constraints under which the EPA is operating. More specifically,
to meet the schedule of an existing consent agreement between the EPA
and the Natural Resources Defense Council, the EPA must complete final
rulemaking approving the December 26, 2000 submittal by October 15,
2001 or must publish a proposed Federal Implementation Plan (FIP) for the Northwest Indiana area by that date.
H. What Are the Basic Components of the State Submittal and What Are the Subjects Covered in This Proposed Rule?
The December 21, 2000 Indiana submittal and this proposed rule
address the following topics: (1) An ozone attainment demonstration for
the ChicagoGaryLake County ozone nonattainment area and the Grid M
modeling domain; (2) the post1999 ROP plan for the Northwest Indiana
area; (3) contingency measures for the post1999 ROP plan and for the
ozone attainment demonstration; (4) ROP and attainment motor vehicle
transportation conformity emission budgets; and (5) Indiana's
commitments for a midcourse review of the ozone attainment
demonstration. This proposed rule also addresses: (1) The status of
rule adoption and implementation needed to support the ozone attainment
demonstration and post1999 ROP plan; (2) revisions to the existing
In this notice, we do not respond to the public comments submitted
on our December 16, 1999 proposed rule on Indiana's April 30, 1998
ozone attainment demonstration submittal. We will address those
comments along with comments addressing this proposed rule when we take
final action on Indiana's ozone attainment demonstration and other plan elements.
III. Ozone Attainment Demonstration and Emissions Control Strategy A. Background Information and Requirements Placed on the Ozone Attainment Demonstration
1. What Clean Air Act Requirements Apply to the State's Ozone Attainment Demonstration?
The CAA requires the EPA to establish National Ambient Air Quality Standards (NAAQS) for certain widespread air pollutants that cause or contribute to air pollution that is reasonably anticipated to endanger public health or welfare. Clean Air Act sections 108 and 109. In 1979, EPA promulgated the 1hour ozone standard at a level of 0.12 parts per million (ppm) (120 parts per billion [ppb]). 44 FR 8202 (February 8, 1979). An area exceeds the 1hour ozone standard each day in which an ambient air quality monitor records an 1hour average ozone concentration above 0.124 ppm. An area violates the ozone standard if, over a consecutive 3year period, more than 3 daily exceedances are recorded or are expected to occur at any monitor in the area or in its immediate downwind environs. The highest of the fourthhigh daily peak ozone concentrations over the 3year period at any monitoring site in the area is called the ozone design value for the area. The CAA required the EPA to designate as nonattainment any area that was violating the 1hour ozone standard, generally based on the air quality monitoring data for the 3 year period from 1987 through 1989. Clean Air Act section 107(d)(4); 56 FR 56694 (November 6, 1991). The CAA further classified these areas, based on the areas' ozone design values, as marginal, moderate, serious, severe, or extreme. Clean Air Act section 181(a). Marginal nonattainment areas were suffering the least significant air quality problems and extreme nonattainment areas had the most significant air quality problems.
The control requirements and date by which attainment of the 1hour
ozone standard needs to be achieved vary with an area's classification.
Marginal areas are subject to the fewest mandated control requirements
and have the earliest ozone attainment date. Moderate, serious, severe,
and extreme areas are subject to more stringent planning and control
requirements but are provided more time to attain the standard. Serious
nonattainment areas were required to attain the 1hour ozone standard
by November 15, 1999, and severe ozone nonattainment areas are [[Page 40806]]
required to attain the ozone standard by November 15, 2005 or November 15, 2007 depending on the areas' ozone design values. The ChicagoGary Lake County ozone nonattainment area is classified as ``severe17'' and its attainment date is November 15, 2007.
Under sections 182(c)(2) and 182(d) of the CAA, states with serious
or severe ozone nonattainment areas were required to submit, by
November 15, 1994, demonstrations of how the nonattainment areas would
attain the 1hour ozone standard and how they would achieve ROP
reductions in VOC emissions of 9 percent of the base year anthropogenic
emissions for each 3year period until the attainment date (following
an initial 15 percent reduction in the VOC emissions by November 15,
1996). In some cases, NO
Notwithstanding significant efforts by the states, in 1995 EPA
recognized that many states in the eastern half of the United States
could not meet the November 15, 1994 time frame for submitting
attainment demonstration SIP revisions because emissions of
On March 2, 1995, Mary D. Nichols, EPA's then Assistant
Administrator for Air and Radiation, issued a memorandum to EPA's
Regional Administrators acknowledging the efforts made by states but
noting the remaining difficulties in making attainment demonstration
SIP submittals.\7\ Recognizing the problems created by ozone transport,
the March 2, 1995 memorandum called for a collaborative process among
the states of the eastern half of the Country to evaluate and address
transport of ozone and its precursors. This memorandum led to the
formation of the Ozone Transport Assessment Group (OTAG) \8\ and
provided for the states to submit the attainment demonstration SIPs
based on the expected time frame for OTAG to complete its evaluation of
ozone transport and to take into consideration the OTAG ozone modeling results.
\7\ Memorandum, ``Ozone Attainment Demonstrations,'' issued March 2, 1995. A copy of the memorandum may be found on EPA's web site at http://www.epa.gove/ttn/oarpg/t1pgm.html. \8\ Letter from Mary A. Gade, Director, State of Illinois Environmental Protection Agency, to the members of the Environmental Council of States (ECOS), dated April 13, 1995.
In June 1997, OTAG completed its process. OTAG submitted to EPA the
results of its technical air quality modeling efforts, which quantified
the impact of the transport of ozone and its precursors. OTAG
recommended consideration of a range of regional, statewide NO
In recognition of the length of the OTAG process, in a December 29,
1997 memorandum, Richard Wilson, EPA's then Acting Assistant
Administrator for Air and Radiation, provided until April 1998 for
states to submit the following elements of their attainment
demonstration SIPs for serious and severe nonattainment areas: (a)
Evidence that the applicable emission control measures in subpart 2 of
part D of title I of the CAA were adopted and implemented or were on an
expeditious course to being adopted and implemented; (b) lists of
measures needed to meet the remaining ROP emissions reduction
requirements and to reach attainment; (c) for severe areas only, a
commitment to adopt and submit the emission control measures necessary
for attainment and the ROP plans through the attainment year by the end
of 2000 \9\; (d) commitments to implement the SIP control programs in a
timely manner to meet ROP emission reduction milestone targets and to
achieve attainment of the ozone standard; and (e) evidence of a public
hearing on each state's submittal.\10\ In addition, state submissions
due in April 1998, under the Wilson policy, should have also included motor vehicle emissions budgets.
\9\ In general, a commitment for severe areas to adopt by December 2000 the control measures necessary for attainment and ROP plans through the attainment year applies to any additional measures necessary for attainment that were not otherwise required to be submitted earlier. (This memorandum was not intended to allow states to delay submission of measures required under the Clean Air Act.) Thus, this commitment applies to any control measures or emission reductions on which any state relies for purposes of a modeled attainment demonstration.
\10\ Memorandum, ``Guidance for Implementing the 1Hour Ozone and PreExisting PM
Building upon the OTAG recommendations and technical analyses, in
November 1997, EPA proposed action addressing the ozone transport
problem. In its proposal, the EPA found that current SIPs in 22 states
and the District of Columbia (23 jurisdictions) did not meet the
requirements of section 110(a)(2)(D) of the CAA because they did not
adequately regulate statewide NO
EPA completed final rulemaking on the NO
On May 25, 1999, the U.S. Court of Appeals for the District of
Columbia issued an order staying the SIP submission requirement of the
The EPA provides that states may rely on a modeled attainment
demonstration supplemented with additional evidence to demonstrate
attainment of the ozone standard.\11\ In order to have complete ozone
modeling attainment demonstration submissions, states should have submitted the required
modeling analyses and identified any additional evidence that EPA should consider in evaluating whether areas will attain the ozone standard.
\11\ The EPA issued guidance on air quality modeling that is used to demonstrate attainment of the 1hour ozone NAAQS. See U.S. EPA (1991), Guideline for Regulatory Application of the Urban Airshed Model, EPA450/491013 (July 1991). A copy may be found on EPA's web site at http://www.epa.gov/ttn/scram/(file name: ``UAMREG''). See also U.S. EPA (1996), Guidance on Use of Modeled Results to Demonstrate Attainment of the Ozone NAAQS, EPA454/B95 007 (June 1996). A copy may be found on EPA's web site at http:// www.epa.gov/ttn/scram/(file name: ``O3TEST'').
For the purposes of demonstrating attainment of the ozone standard,
the CAA (section 182(c)(2)(A)) requires states with serious and severe
ozone nonattainment areas to use photochemical dispersion modeling or
an analysis method EPA determines to be as effective to assess the
adequacy of emission control strategies and to demonstrate attainment
of the ozone standard. The photochemical dispersion modeling system is
set up using observed meteorological conditions conducive to the
formation of ozone. The meteorological conditions are selected based on
historical data for high ozone periods in the nonattainment area or in
its associated modeling domain. Emissions for a base year and monitored
ozone and ozone precursor (generally VOC and NO
A modeling domain is chosen that encompasses the ozone nonattainment area and surrounding upwind and downwind areas. Attainment of the ozone standard is demonstrated when all predicted ozone concentrations in the attainment year in the modeling domain are at or below the ozone NAAQS or at an acceptable upper limit above the NAAQS permitted under certain conditions as explained in EPA's guidance. An optional WeightOfEvidence (WOE) determination may be used to address uncertainty inherent in the application of photochemical grid models. See the discussion of possible WOE determination tests and analyses below.
The EPA guidance identifies the features of a modeling analysis that are essential to obtain credible results. First, the State must develop and implement a modeling protocol. The modeling protocol describes the methods and procedures to be used in conducting the modeling analyses and provides for policy oversight and technical review by individuals responsible for developing or assessing the attainment demonstration (state and local agencies, EPA regional offices, the regulated community, and public interest groups). Second, for purposes of developing the information to put into the model, the state must select historical high ozone days (days with ozone concentrations exceeding the ozone standard) that are representative of the ozone pollution problem for the nonattainment area. Third, the state needs to identify the appropriate dimensions of the area to be modeled, i.e., the modeling domain size. The modeling domain should be larger than the designated ozone nonattainment area to reduce uncertainty in the nonattainment area boundary conditions and should include any large upwind sources just outside of the ozone nonattainment area. In general, the modeling domain is considered to be the area where control measures are most beneficial to bring the nonattainment area into attainment of the ozone NAAQS. Fourth, the state needs to determine the modeling grid resolution (the modeling domain is divided into a threedimensional grid). The horizontal and vertical resolutions in the modeling domain affect the modeled dispersion and transport of emission plumes. Artificially large grid cells (too few vertical layers and horizontal grids for a given modeled volume) may artificially dilute pollutant concentrations and may not properly consider impacts of complex terrain, meteorology, and land/ water interfaces. Fifth, the state needs to generate meteorological data and emissions that describe atmospheric conditions and inputs reflective of the selected high ozone days. Finally, the state needs to verify that the modeling system is properly simulating the chemistry and atmospheric conditions through diagnostic analyses and model performance tests (generally referred to as model validation). Once these steps are satisfactorily completed, the model is ready to be used to generate air quality estimates to evaluate emission control strategies and to support an ozone attainment demonstration.
The modeled attainment test compares modelpredicted 1hour daily maximum ozone concentrations in all grid cells for the attainment year (2007 for the ChicagoGaryLake County ozone nonattainment area) with all selected emission control measures (emissions control strategy) in place to the level of the ozone NAAQS. A predicted peak ozone concentration above 0.124 ppm (124 ppb) indicates that the area may exceed the ozone standard in the attainment year under the tested emissions control strategy and that the emissions control strategy may be inadequate to attain the ozone standard.
EPA's guidance recommends that states use either of two modeled
attainment or exceedance tests for the ozone attainment demonstration,
a deterministic test or a statistical test. The deterministic test
requires a state to compare predicted 1hour daily maximum ozone
concentrations for each modeling domain grid cell for each modeled day
\12\ to the ozone attainment level of 0.124 ppm. If none of the predictions exceed 0.124 ppm, the test is passed.
\12\ The initial, ``rampup'' day for each modeled high ozone episode is excluded from this determination.
The statistical test takes into account the fact that the 1hour ozone NAAQS allows exceedances. If, over a 3year period, an area has an average of 1 or fewer daily exceedances per year at any monitoring site, the area is not violating the ozone standard. Thus, if the state models an extreme day, considering meteorological conditions that are very conducive to high ozone levels, the statistical test provides that a prediction of an 1hour ozone concentration above 0.124 ppm up to a certain upper limit may be consistent with attainment of the standard.
The acceptable upper limit for modeled peak ozone concentrations in
the statistical test is determined by examining the levels of ozone
standard exceedances at monitoring sites which meet the 1hour ozone
NAAQS. For example, a monitoring site for which the four highest 1hour
average ozone concentrations over a 3year period are 0.136 ppm, 0.130
ppm, 0.128 ppm, and 0.122 ppm is attaining the standard. To identify an
acceptable upper limit, the statistical likelihood of observing ozone
air quality exceedances of the standard of various concentrations is
equated to the relative severity of the modeled day. The upper limit
generally represents the maximum ozone concentration observed at a
location on a single day, and would be the only ozone reading above the
standard that would be expected to occur no more than an average of
once a year over a 3year period. Therefore, if the maximum ozone
concentration predicted by the model is below the acceptable upper
limit, in this case 0.136 ppm, then EPA might conclude that the modeled
attainment test is passed. Generally, exceedances well above 0.124 ppm
are very unusual at monitoring sites meeting the ozone NAAQS. Thus,
these upper limits are rarely substantially higher than the attainment level of 0.124 ppm.
4. What Additional Analyses May Be Considered When the Ozone Modeling Fails To Show Attainment of the Ozone Standard?
When the ozone modeling does not conclusively demonstrate
attainment of the ozone standard through either a deterministic test or
a statistical test, additional analyses may be presented to help
determine whether the area nevertheless will attain the standard. As
with other predictive tools, there are inherent uncertainties in some
of the photochemical modeling inputs, such as the meteorological and
emissions data bases for individual days and in the methodology used to
assess the severity of an exceedance at individual sites. EPA's
guidance recognizes these limitations, and provides a means for
considering other evidence to help assess whether attainment of the
NAAQS is likely. The process by which this is done is the WOE determination.\13\
\13\ States may choose to submit WOE determinations even when the ozone modeling results pass either the deterministic test or the statistical test. This may be done to support the attainment demonstration, recognizing that the ozone modeling results possess a certain degree of uncertainty.
Under a WOE determination, a state can rely on and EPA will consider factors such as: Other modeled attainment tests, e.g., a rollback analysis; Other modeled outputs, e.g., changes in the predicted frequency and pervasiveness of ozone standard exceedances and predicted changes in an area's ozone design value; actual observed air quality trends; estimated emissions trends; analyses of air quality monitoring data; the responsiveness of the model predictions to further emission controls; and, whether there are additional emission control measures that are or will be approved into the SIP but that were not included in the ozone modeling analysis. This list is not an exhaustive list of factors that may be considered, and the factors considered could vary from case to case. EPA's guidance contains no limit on how close a modeled attainment test (a deterministic test or a statistical test) must be to passing to conclude that other evidence besides an attainment test is sufficiently compelling to suggest attainment. The further a modeled attainment test is from being passed, however, the more compelling the WOE determination needs to be.
EPA's 1996 modeling guidance also recognizes a need to perform a
midcourse review as a means for addressing uncertainty in the modeling
results, particularly if a WOE determination is needed to support an
ozone attainment demonstration. Because of the uncertainty in long term
projections, EPA believes a viable attainment demonstration that relies
on a WOE determination needs to contain provisions for periodic review
of monitoring, emissions, and modeling data to assess the extent to
which refinements to emission control measures are needed. The mid course review is further discussed below.
5. Besides the Modeled Attainment Demonstration and Adopted Emission Control Strategy, What Other Elements Must be Addressed in the Attainment Demonstration SIP?
In addition to the modeling analysis and WOE determination supporting the attainment demonstration, the EPA has identified the following key elements which must also be adopted by the state and approved by the EPA in order for EPA to approve the 1hour ozone attainment demonstration SIPs.
a. Clean Air Act measures, and other measures relied on in the modeled attainment demonstration. This includes adopted and submitted rules for all Clean Air Act required measures for the specific area classification. This also includes measures that may not be required given the area's ozone classification but that the state relied on in its attainment demonstration or in its ROP plan.
The state should have adopted the emission control measures required under the CAA for the area's ozone nonattainment
classification. In addition, states with severe ozone nonattainment areas had until December 2000 to adopt and submit additional emission control measures needed to achieve ROP through the attainment year and to attain the ozone standard. For purposes of fully approving a state's SIP, the state needs to adopt and submit rules for all VOC and NO
Table I presents a summary of the CAA requirements that need to be
met for each severe ozone nonattainment area. These requirements are
specified in section 182 of the CAA. Information on more measures that
states may have adopted or relied on in their current SIP submissions is not shown in the table.
\14\ The NO
\15\ The NO
\16\ To provide interim progress, EPA accepted 9 percent VOC/ NO
requirements through the submittal of a final ROP plan with adopted emission control regulations by December 2000. We review Indiana's post1999 ROP plan later in this proposed rule.
Table I.CAA Requirements for Severe Ozone Nonattainment Areas
As provided above, any emission controls assumed by a state within a local ozone modeling domain must be adopted by the state and approved by us to receive our final approval of the state's 1hour ozone attainment demonstration SIP.
c. Motor vehicle emissions budgets. The EPA believes that
attainment demonstration and ROP SIPs must necessarily estimate the
motor vehicle VOC and NO
d. Midcourse review. An enforceable commitment to conduct a mid course review (MCR) and evaluation of the attainment demonstration based on air quality and emissions trends at some time prior to the attainment year must be included in the attainment demonstration SIP before it can be approved by the EPA, particularly if the SIP depends on a WOE determination to demonstrate attainment of the ozone standard. States with severe and extreme ozone nonattainment areas should also provide for a MCR because of the uncertainty inherent in emission projections that extend 10 to 15 years into the future. (See EPA's ``Guidance on Use of Modeled Results to Demonstrate Attainment of the Ozone NAAQS,'' June 1996.) The MCR shows whether the adopted emission control measures and emissions control strategy (all measures combined into a single plan) are sufficient in timing and extent to reach attainment of the ozone standard by the area's attainment deadline, or whether additional emission control measures may be necessary.
A MCR is a reassessment of the modeling analyses and more recent monitoring and emissions data to determine if a prescribed emissions control strategy is resulting in emission reductions and air quality improvements needed to attain the ozone standard as expeditiously as practicable but no later than the statutory attainment date. The EPA believes that an enforceable commitment to perform a MCR is a critical element of a WOE determination.
For severe areas, such as the ChicagoGaryLake County ozone
nonattainment area, the state(s) must submit an enforceable commitment
(Indiana has submitted such a commitment as discussed below). The
commitment must provide the date by which the MCR will be completed.
The EPA believes that the MCR process should be done immediately
following the ozone season (April through October in Indiana) in which
the states have implemented the NO
Following submittal of MCR analysis results, we and the state would
review the results and determine whether the state needs to adopt and
submit additional emission control measures for purposes of attainment.
We are not requesting that states commit now to adopt new emission
control measures as a result of this process. It would be impractical
for the states to make a commitment for such control measures that is
specific enough to be considered enforceable. Moreover, the MCR could
indicate that upwind states may need to adopt some or all of the
additional emission controls needed to ensure that a downwind state/
area attains the ozone standard. We would determine whether additional
emission controls are needed in the state in which a nonattainment area
is located or in upwind states, or in both. We would require the
appropriate state(s) to adopt and submit new emission control measures
within a period specified at that time. We anticipate that these
findings would be made as SIP Calls under section 110(k)(5) of the CAA
and, therefore, the period for the submission of the measures would be
no longer than 18 months after we make a finding. A guidance document
regarding the MCR process is located on EPA's web site at http:// www.epa.gov/ttn/scram.
6. What Are the Relevant EPA Policy and Guidance Documents?
The relevant policy documents for ozone attainment demonstrations and their locations on EPA's web site are listed below:
a. U.S. EPA, Guideline for Regulatory Application of the Urban Airshed Model, EPA450/491013, (July 1991), Web site: http:// www.epa.gov/ttn/scram/ (file name: ``UAMREG'').
b. U.S. EPA, Guidance on Use of Modeled Results to Demonstrate Attainment of the Ozone NAAQS, EPA454/B95007, (June 1996), Web site: http://www.epa.gov/ttn/scram/ (file name: ``O3TEST'').
c. Memorandum, ``Ozone Attainment Demonstrations,'' from Mary D. Nichols, issued March 2, 1995, Web site:http://www.epa.gov/ttn/oarpg/ t1pgm.html.
d. Memorandum, ``Extension of Attainment Dates for Downwind Transport Areas,'' issued July 16, 1998,
Web site: http://www.epa.gov/ttn/oarpg/t1pgm.html.
e. Memorandum, ``Guidance for Implementing the 1Hour Ozone and
f. ``Guidance for Improving Weight of Evidence Through Identification of Additional Emission Reductions, Not Modeled,'' U.S. EPA, Office of Air Quality Planning and Standards, November 1999, Web site: http://www.epa.gov/ttn/scram/.
g. ``Serious and Severe Ozone Nonattainment Areas: Information on Emissions, Control Measures Adopted or Planned and Other Available Control Measures,'' Draft Report, U.S. EPA, Ozone Policy and Strategies Group, November 3, 1999.
h. Memorandum, ``Guidance on Motor Vehicle Emissions Budgets in 1 hour Attainment Demonstrations,'' from Merrylin ZawMon, Office of Mobile Sources, November 3, 1999, Web site: http://www.epa.gov/oms/ transp/traqconf.htm.
i. Memorandum, ``1Hour Ozone Attainment Demonstrations and Tier 2/ Sulfur Rulemaking,'' from Lydia Wegman and Merrylin ZawMon, Office of Air Quality Planning and Standards and Office of Mobile Sources, November 8, 1999, Web site: http://www.epa.gov/oms/transp/traqconf.htm.
j. Draft Memorandum, ``1Hour Ozone NAAQSMidCourse Review
Guidance,'' from John Seitz, Director, Office of Air Quality Planning
and Standards, Web sit: http://www.epa.gov/ttn/scram/. B. Technical Review of the State's Submittal
1. When Was the Attainment Demonstration Addressed in Public Hearings, and When Was the Attainment Demonstration Submitted to the EPA?
The State of Indiana held a public hearing on the ozone attainment
demonstration on November 15, 2000. IDEM submitted the attainment demonstration to EPA on December 21, 2000.
2. What Are the Basic Technical Components of the Submittal?
Since Indiana, along with Illinois, Michigan, and Wisconsin, jointly participates in the Lake Michigan Air Directors Consortium (LADCO) and since LADCO has conducted the ozone analyses used to develop the ozone attainment demonstration, technical support documents developed by LADCO form the main bases for Indiana's ozone attainment demonstration. Three documents from LADCO provide much of the technical support for the attainment demonstration. These documents are:
a. ``Midwest Subregional Modeling: 1Hour Attainment Demonstration for Lake Michigan AreaSummary,'' LADCO, September 18, 2000;
b. ``Technical Support DocumentMidwest Subregional Modeling: 1 Hour Attainment Demonstration for Lake Michigan Area,'' LADCO, September 18, 2000; and
c. ``Technical Support DocumentMidwest Subregional Modeling: Emissions Inventory,'' LADCO, September 27, 2000.
Indiana, like Illinois and Wisconsin, has included a statespecific cover letter and a statespecific synopsis of the ozone attainment demonstration. As part of their respective ozone attainment demonstrations, all three States included the LADCO documents listed above to support their adopted emission control strategies and ozone attainment demonstrations.
A number of other related submittal components are discussed in
later sections of this proposed rule. This section deals exclusively
with the technical aspects of Indiana's 1hour ozone attainment
demonstration, focusing on the ozone modeling results and supporting air quality and emissions analyses.
3. What Modeling Approach Was Used in the Analyses to Develop and Validate the Ozone Modeling System?
The LADCO States, as participants in the Lake Michigan Ozone Study (designed to establish the modeling system and its base input data and to validate the modeling system) and in the Lake Michigan Ozone Control Program (designed to select and test possible emission control strategies), used the same modeling approach to develop the basis for each State's ozone attainment demonstration, although each State selected a different emissions control strategy for their respective ozone attainment demonstration. The modeling approach is documented in LADCO's September 18, 2000 Technical Support Document (TSD) and is summarized in LADCO's September 18, 2000 modeling summary (see above).
The heart of the modeling system is the Urban Airshed ModelVersion V (UAMV) photochemical dispersion model developed originally for specific application in the Lake Michigan area. This is the same version of the model that was used during the OTAG analysis of ozone transport and ozone transport control measures.
For purposes of the local ozone attainment demonstration, UAMV was
implemented on a local modeling domain and grid configuration that was established based on consideration of areas of high ozone
concentrations (generally the ozone nonattainment areas) in the Lake Michigan States and of possible upwind source areas impacting these high concentration areas. The primary modeling domain is referred to as Grid M. This grid extends east to the most eastern portion of Michigan (and to central Ohio, eastern Kentucky, and eastern Tennessee); north to the northern end of Michigan's Lower Peninsula (and to the north of Green Bay, Wisconsin); west to include the eastern thirds of Iowa and Missouri; and south to the southern border of Tennessee. The horizontal grid is rectangular in shape (see Figure 1 of the September 18, 2000 TSD). The modeling has the following horizontal and vertical resolutions:
Approximately 12 kilometers x 12 kilometersall modeling runs.
Approximately 4 kilometers x 4 kilometersfor selected runs to give better resolution in the area along the western shore of Lake Michigan.
7 vertical layers with the following height ranges (above terrain) in meters: 050; 50100; 100250; 250500; 5001500; 15002500; and 25004000.
A subregional portion of the grid, centered (east to west) on the lower portion of Lake Michigan, was also considered to allow a more detailed analysis of the high ozone areas of Grid M. The use of Grid M and the subregional portion of Grid M allowed the consideration of both urban scale analyses and ozone transport. It should be noted that the modeling results from the modeling runs with the tighter 4 kilometer resolution were generally consistent with the results for the 12 kilometer resolution.
Four high ozone episodes in the Lake Michigan area were modeled. These episodes were: June 2228, 1991; July 1421, 1991; June 1325, 199
FOR FURTHER INFORMATION CONTACT
Edward Doty, Regulation Development Section, Air Programs Branch (AR18J), U.S. Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, Telephone Number: (312) 8866057, EMail Address: firstname.lastname@example.org.