[Federal Register Volume 64, Number 241 (Thursday, December 16, 1999)]
[Proposed Rules]
[Pages 70514-70531]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-31721]



[[Page 70514]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[IN90-1; FRL-6503-2]


Approval and Promulgation of Implementation Plans; Indiana; Ozone

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
conditionally approve the 1-hour ozone attainment demonstration State 
Implementation Plan (SIP or plan) for the Chicago-Gary-Lake County 
severe ozone nonattainment area submitted by the Indiana Department of 
Environmental Management (IDEM) on April 30, 1998. This proposed 
conditional approval is based on the submitted modeling analysis and on 
the State's commitments to adopt and submit a final ozone attainment 
demonstration SIP and a post-1999 Rate of Progress (ROP) plan, 
including the necessary State air pollution control regulations to 
complete the attainment demonstration and ROP plans, by December 31, 
2000. The EPA is also proposing, in the alternative, to disapprove this 
attainment demonstration plan if, by December 31, 1999, the State does 
not select a control strategy associated with its submitted modeling 
analysis and submits adequate motor vehicle emissions budgets for 
Volatile Organic Compounds (VOC) and Oxides of Nitrogen 
(NOX) for the ozone nonattainment area that comply with 
EPA's conformity regulations and that are derived from the selected 
emissions control strategy that supports attainment of the 1-hour ozone 
standard. In addition, the State must, by December 31, 1999, submit an 
enforceable commitment to conduct a mid-course review of the ozone 
attainment plan in 2003.

DATES: Written comments must be received on or before February 14, 
2000.

ADDRESSES: Written comments should be sent to: Jay Bortzer, Chief, 
Regulation Development Section, Air Programs Branch (AR-18J), U.S. 
Environmental Protection Agency, 77 West Jackson Boulevard, Chicago, 
Illinois 60604.
    Copies of the State submittal and EPA's technical support document 
are available for public inspection during normal business hours at the 
following address: United States Environmental Protection Agency, 
Region 5, Air and Radiation Division, 77 West Jackson Boulevard, 
Chicago, Illinois 60604. (Please telephone Mark Palermo at (312) 886-
6082 before visiting the Region 5 Office.)

FOR FURTHER INFORMATION CONTACT: Edward Doty, Regulation Development 
Section, Air Programs Branch (AR-18J), U.S. Environmental Protection 
Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, 
Telephone Number (312) 886-6057, E-Mail Address 
[email protected].

SUPPLEMENTARY INFORMATION: This section provides background information 
on attainment demonstration SIPs for the 1-hour ozone National Ambient 
Air Quality Standard (NAAQS or standard) and an analysis of Indiana's 
1-hour ozone attainment demonstration for the Chicago-Gary-Lake County 
ozone nonattainment area.

Table of Contents

I. Background Information
II. Technical Review of the Submittal
III. Proposed Action
IV. Administrative Requirements

I. Background Information

A. Basis for the State's Attainment Demonstration SIP

What Are the Relevant Clean Air Act Requirements?
    The Clean Air Act requires the EPA to establish national ambient 
air quality standards for certain widespread 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 1-hour 0.12 parts per million (ppm) ground-level 
ozone standard. 44 FR 8202 (Feb. 8, 1979). Ground-level ozone is not 
emitted directly by sources. Rather, emissions of NOX and 
VOC react in the presence of sunlight to form ground-level ozone. 
NOX and VOC are referred to as precursors of ozone.
    An area exceeds the 1-hour ozone standard each time an ambient air 
quality monitor records a 1-hour average ozone concentration above 
0.124 ppm on any day. An area violates the standard if, over a 
consecutive 3-year period, more than 3 daily exceedances are expected 
to occur at any monitor in the area or in its immediate downwind 
environs. The highest of the fourth-highest daily peak ozone 
concentrations over the 3 year period at any one monitoring site in the 
area is called the design value for the area. The Clean Air Act, as 
amended in 1990, required EPA to designate as nonattainment any area 
that was violating the 1-hour ozone standard, generally based on air 
quality monitoring data from the 3-year period from 1987 through 1989. 
Clean Air Act section 107(d)(4); 56 FR 56694 (Nov. 6, 1991). The Clean 
Air Act further classified these areas, based on the areas' design 
values, as marginal, moderate, serious, severe or extreme. Clean Air 
Act section 181(a). Marginal areas were suffering the least significant 
air quality problems while the areas classified as severe and extreme 
had the most significant air quality problems.
    The control requirements and date by which attainment needs to be 
achieved vary with an area's classification. Marginal areas are subject 
to the fewest mandated control requirements and have the earliest 
attainment date. Severe and extreme areas are subject to more stringent 
planning requirements but are provided more time to attain the 
standard. Serious areas are required to attain the 1-hour standard by 
November 15, 1999, and severe areas are required to attain by November 
15, 2005 or November 15, 2007, depending on the areas' ozone design 
values. The Chicago-Gary-Lake County ozone nonattainment area is 
classified as severe-17 and its attainment date is November 15, 2007. 
The Chicago-Gary-Lake County ozone nonattainment area is defined (40 
CFR 81.314 and 81.315) to contain Cook, DuPage, Grundy (Aux Sable and 
Goose Lake Townships only), Kane, Kendall (Oswego Township only), Lake, 
McHenry, and Will Counties in Illinois, and Lake and Porter Counties in 
Indiana. This proposed rulemaking focuses on the Indiana portion of 
this nonattainment area. A separate proposed rulemaking in today's 
Federal Register deals with the Illinois portion of this nonattainment 
area.
    Under section 182(c)(2) and (d) of the Clean Air Act, serious and 
severe areas were required to submit, by November 15, 1994, 
demonstrations of how they would attain the 1-hour standard and how 
they would achieve ROP reductions in VOC emissions of 9 percent for 
each 3-year period until the attainment. (In some cases, NOX 
emission reductions can be substituted for the required VOC emission 
reductions to achieve ROP.) Today, in this proposed rule, EPA is 
proposing action on the attainment demonstration SIP submitted by 
Indiana for the Chicago-Gary-Lake County ozone nonattainment area and 
its associated ozone modeling domain and on the State's commitment to 
complete the attainment demonstration SIP for this ozone nonattainment 
area by December 2000. EPA is also proposing action on the State's 
commitment to submit ROP target calculations and the adopted measures 
to achieve ROP by December 2000. In addition, elsewhere in this Federal 
Register, EPA is today

[[Page 70515]]

proposing to take action on ozone attainment demonstraion SIPs, and, in 
some cases ROP SIPs, for other serious or severe 1-hour ozone 
nonattainment areas. The additional ozone attainment demonstration and 
ROP SIPs addressed elsewhere in this Federal Register cover the ozone 
nonattainment areas of Greater Connecticut (CT), Springfield (Western 
Massachusetts) (MA), New-York-North New Jersey-Long Island (NY-NJ-CT), 
Baltimore (MD), Philadelphia-Wilmington-Trenton (PA-NJ-DE-MD), 
Metropolitan Washington D.C. (DC-MD-VA), Atlanta (GA), Milwaukee-Racine 
(WI), Chicago-Gary-Lake County (IL-IN) (Illinois portion of this area), 
and Houston-Galveston-Brazoria (TX).
    In general, an attainment demonstration SIP includes a modeling 
analysis component showing how the area will achieve the standard by 
its attainment date and the emission control measures necessary to 
achieve attainment. Another component of the attainment demonstration 
SIP is a motor vehicle emissions budget for transportation conformity 
purposes. Transportation conformity is a process for ensuring that 
States consider the effects of emissions associated with new or 
improved federally-funded roadways on attainment of the standard. As 
described in section 176(c)(2)(A) of the Clean Air Act, attainment 
demonstrations necessarily include the estimates of motor vehicle 
emissions that are consistent with attainment, which then act as a 
budget or ceiling for the purposes of determining whether 
transportation plans and projects conform to the attainment SIP.
What is the History and Time Frame for the State Attainment 
Demonstration SIP and How Is It Related to the NOX SIP Call?
    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 1994 time frame for submitting an 
attainment demonstration SIP because emissions of NOX and 
VOC in upwind States (and the ozone formed by these emissions) affected 
these nonattainment areas and the full impact of this effect had not 
yet been determined. This phenomenon is called ozone transport.
    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.1 Recognizing the problems created by ozone 
transport, the March 2, 1995 memorandum called for a collaborative 
process among the States in 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) 
2 and provided for the States to submit the attainment 
demonstration SIPs based on the expected time frames for OTAG to 
complete its evaluation of ozone transport.
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    \1\ 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.gov/ttn/oarpg/t1pgm.html.
    \2\ Letter from Mary A. Gade, Director, State of Illinois 
Environmental Protection Agency to Environmental Council of States 
(ECOS) Members, dated April 13, 1995.
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    In June 1997, OTAG concluded and provided EPA with recommendations 
regarding ozone transport. The OTAG generally concluded that transport 
of ozone and the precursor NOX is significant and should be 
reduced regionally to enable States in the eastern half of the country 
to attain the ozone NAAQS.
    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: (1) 
Evidence that the applicable control measures in subpart 2 of part D of 
title I of the Clean Air Act were adopted and implemented or were on an 
expeditious course to being adopted and implemented; (2) a list of 
measures needed to meet the remaining ROP emissions reduction 
requirement and to reach attainment; (3) for severe areas only, a 
commitment to adopt and submit the control measures necessary for 
attainment and the ROP plans through the attainment year by the end of 
2000 3; (4) a commitment to implement the SIP control 
programs in a timely manner and to meet ROP emissions reductions and 
attainment; and (5) evidence of a public hearing on the State 
submittal.4 This submission is sometimes referred to as the 
Phase II submission. Motor vehicle emission budgets can be established 
based on a commitment to adopt the measures needed for attainment and 
identification of the measures needed. Thus, State submissions due in 
April 1998 under the Wilson policy should have included a motor vehicle 
emissions budget.
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    \3\ 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. (For example, this memorandum was not intended to 
allow States to delay submission of measures required under the 
Clean Air Act, such as inspection and maintenance (I/M) programs or 
reasonable available control technology (RACT) regulations, required 
at an earlier time.) Thus, this commitment applies to any control 
measures or emission reductions on which the State relied for 
purposes of the modeled attainment demonstration. To the extent 
Indiana has relied on a commitment to submit these measures by 
December 2000, EPA is proposing a conditional approval of the 
attainment demonstration. Some States with severe nonattainment 
areas submitted the actual adopted control measures and are not 
relying on a commitment.
    The EPA recognizes that motor vehicle emission budgets can be 
established from the items listed in the Wilson memorandum.
    \4\ Memorandum, ``Guidance for Implementing the 1-Hour Ozone and 
Pre-Existing PM 10 NAAQS,'' issued December 29, 1997. A copy of this 
memorandum may be found on EPA's web site at http://www.epa.gov/ttn/
oarpg/t1pgm.html.
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    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) were insufficient to 
provide for attainment and maintenance of the 1-hour standard because 
they did not regulate NOX emissions that significantly 
contribute to ozone transport. 62 FR 60318 (Nov. 7, 1997). The EPA 
finalized that rule in September 1998, calling on the 23 jurisdictions 
to revise their SIPs to require NOX emissions reductions 
within each State to a level consistent with a NOX emissions 
budget identified in the final rule. 63 FR 57356 (Oct. 27, 1998). This 
final rule is commonly referred to as the NOX SIP call.
What Is the Time Frame for Taking Action on the Attainment 
Demonstration SIPs for the Serious and Severe Nonattainment Areas?
    The States generally submitted the SIPs between April and October 
1998; some States are still submitting additional revisions. Under the 
Clean Air Act, EPA is required to approve or disapprove a State's 
submission no later than 18 months following submission. (The statute 
provides up to 6 months for a completeness determination and an 
additional 12 months for approval or disapproval.) The EPA believes 
that it is important to keep the process moving forward in evaluating 
these plans and, as appropriate, approving them. Thus, in today's 
Federal Register, EPA is proposing to take action on the serious and 
severe 1-hour ozone attainment demonstration SIPs and intends to take

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final action on these submissions over the next 6-12 months. The reader 
is referred to individual dates in this document for specific 
information on actions leading to EPA's final rulemaking on these 
plans.
What Are the Options for Action on the State Attainment Demonstration 
SIPs?
    Depending on the circumstances unique to each of the SIP 
submissions on which EPA is proposing action today, EPA is proposing 
one or more of these types of approval or disapproval in the 
alternative. In addition, these proposals may inentify additional 
actions that will be necessary from the State.
    The Clean Air Act provides for EPA to approve, disapprove, 
partially approve or conditionally approve a State's plan submission. 
The EPA must fully approve the submission if it meets the attainment 
demonstration requirement of the Clean Air Act. If the 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, or may conditionally 
approve based on a State's commitment to correct the deficiency by a 
date certain, which can be no later than one year from the date of 
EPA's final conditional approval.
    The EPA may partially approve a submission if separable parts of 
the submission, standing alone, are consistent with the Clean Air Act. 
For example, if a State submits a modeled attainment demonstration, 
including control measures, but the modeling does not demonstrate 
attainment, EPA could approve the control measures and disapprove the 
modeling for failing to demonstrate attainment.
    The EPA may issue a conditional approval based on a State's 
commitment to expeditiously correct a deficiency by a date certain that 
can be no later than one year following EPA's final conditional 
approval. Such commitments do not need to be independently enforceable 
because, if the State does not fulfill its commitment, the conditional 
approval is converted to a disapproval after the deadline for the 
correction of the deficiency. For example, if a State commits to submit 
additional control measures and fails to submit them or EPA determines 
the State's submission of the control measures is incomplete, the EPA 
will notify the State by letter that the conditional approval has been 
converted to a disapproval. If the State submits control measures that 
EPA determines are complete or that are deemed complete, EPA will 
determine through rulemaking whether the State's attainment 
demonstration is fully approvable or whether the conditional approval 
of the attainment demonstration should be converted to a disapproval.
    Finally, EPA has recognized 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. Unlike the commitment 
for 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 approval action. 
Thus, EPA may accept such an enforceable commitment where it is 
infeasible for the State to accomplish the necessary action in the 
short term.

B. Components of a Modeled Attainment Demonstration

    The EPA provides that States may rely on a modeled attainment 
demonstration supplemented with additional evidence to demonstrate 
attainment.5 In order to have a complete modeling 
demonstration submission, States should have submitted the required 
modeling analysis and identified any additional evidence that EPA 
should consider in evaluating whether the area will attain the 
standard.
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    \5\ The EPA issued guidance on the air quality modeling that is 
used to demonstrate attainment with the 1-hour ozone NAAQS. See U.S. 
EPA, (1991), Guideline for Regulatory Application of the Urban 
Airshed Model, EPA-450/4-91-013, (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, EPA-454/B-95-
007, (June 1996). A copy may be found on EPA's web site at http://
www.epa.gov/ttn/scram/ (file name: ``O3TEST'').
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What Are the Modeling Requirements for the Atteinment Demonstration?
    For purposes of demonstrating attainment, the Clean Air Act 
requires serious and severe areas to use photochemical grid modeling or 
an analytical method EPA determines to be as effective. The 
photochemical grid model is set up using meteorological conditions 
conducive to the formation of ozone. Emissions for a base year are used 
to evaluate the model's ability to reproduce actual monitored air 
quality values. Following validation of the modeling system for a base 
year, emissions are projected to an attainment year to predict air 
quality changes in the attainment year due to the emission changes, 
which include growth up to and controls implemented by the attainment 
year. A modeling domain is chosen that encompasses the nonattainment 
area. Attainment is demonstrated when all predicted concentrations 
inside the modeling domain are at or below the NAAQS or at an 
acceptable upper limit above the NAAQS permitted under certain 
conditions by EPA's guidance. When the predicted concentrations are 
above the NAAQS, an optional weight of evidence determination which 
incorporates, but is not limited to, other analyses, such as air 
quality and emissions trends, may be used to address uncertainty 
inherent in the application of photochemical grid models.
    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 air pollution days, i.e., days in the past with high 
ozone concentrations exceeding the 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 domain should be larger 
than the designated nonattainment area to reduce uncertainty in the 
boundary conditions and should include any large upwind sources just 
outside the nonattainment area. In general, the domain is considered 
the local area where control measures are most beneficial to bring the 
area into attainment. Fourth, the State needs to determine the grid 
resolution. The horizontal and vertical resolutions in the model affect 
the dispersion and transport of emission plumes. Artificially large 
grid cells (too few vertical layers and horizontal grids) may dilute 
concentrations and may not properly consider impacts of complex 
terrain, complex meteorology, and land/water interfaces. Fifth, the 
State needs to generate meteorological data and emissions that describe 
atmospheric conditions and emissions inputs reflective of the selected 
high ozone days. Finally, the State needs to verify that the modeling 
system is properly

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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 support an 
attainment demonstration.
    The modeled attainment test compares model-predicted 1-hour daily 
maximum concentrations in all grid cells for the attainment year to the 
level of the NAAQS. A predicted peak ozone concentration above 0.124 
ppm indicates that the area is expected to exceed the standard in the 
attainment year. This type of test is often referred to as an 
exceedance test. The EPA's guidance recommends that States use either 
of two modeled attainment or exceedance tests for the 1-hour ozone 
NAAQS: A deterministic test or a statistical test.
    The deterministic test requires the State to compare predicted 1-
hour daily maximum ozone concentrations for each modeled day 
6 to the attainment level of 0.124 ppm. If none of the 
predictions exceed 0.124 ppm, the test is passed.
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    \6\ The initial, ``ramp-up'' days for each episode are excluded 
from this determination.
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    The statistical test takes into account the fact that the form of 
the 1-hour ozone standard allows exceedances. If, over a 3-year period, 
the area has an average of 1 or fewer exceedances per year at any 
monitoring site, the area is not violating the standard. Thus, if the 
State models a very extreme day (considering meteorological conditions 
that are very conducive to high ozone levels and that should lead to 
fewer than 1 exceedance per year at any location in the nonattainment 
area and modeling domain over a 3 year period), the statistical test 
provides that a prediction above 0.124 ppm up to a certain upper limit 
may be consistent with attainment of the standard. (The form of the 1-
hour standard allows for up to 3 days with peak 1-hour ozone 
concentrations above the standard over a 3-year period at any 
monitoring site before an area is considered to be in violation of the 
NAAQS.)
    The acceptable upper limit above 0.124 ppm is determined by 
examining the size of exceedances at monitoring sites which meet the 1-
hour NAAQS. For example, a monitoring site for which the four highest 
1-hour average concentrations over a 3-year 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 severity of the modeled day. The upper limit generally 
represents the maximum ozone concentration observed at a location on a 
single day and it would be the only reading above the standard that 
would be expected to occur no more than an average of once a year over 
a 3-year 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 NAAQS. Thus, these upper limits 
are rarely substantially higher than the attainment level of 0.124 ppm.
What Are the Additional Analyses That May Be Considered When the 
Modeling Fails To Show Attainment?
    When the modeling does not conclusively demonstrate attainment, 
additional analyses may be presented to help determine whether the area 
will attain the standard. As with other predictive tools, there are 
inherent uncertainties associated with modeling and its results. For 
example, there are uncertainties in some of the 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. The 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 
called a weight-of-evidence (WOE) determination.
    Under a WOE determination, the 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 exceedances and predicted 
changes in the design value; actual observed air quality trends; 
estimated emissions trends; analyses of air quality monitored data; the 
responsiveness of the model predictions to further controls; and, 
whether there are additional control measures that are or will be 
approved into the SIP but were not included in the modeling analysis. 
This list is not an exhaustive list of factors that may be considered 
and these factors could vary from case to case. The EPA's guidance 
contains no limit on how close a modeled attainment test must be to 
passing to conclude that other evidence besides an attainment test is 
sufficiently compelling to suggest attainment. However, the further a 
modeled attainment test is from being passed, the more compelling the 
WOE needs to be.
    The EPA's 1996 modeling guidance also recognizes a need to perform 
a mid-course review as a means for addressing uncertainty in the 
modeling results. 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 discussed below.

C. Framework for Proposing Action on the Attainment Demonstration SIPs

Besides the Modeled Attainment Demonstration, What Other Issues Must be 
Addressed in the Attainment Demonstration SIPs?
    In addition to the modeling analysis and WOE support demonstrating 
attainment, the EPA has identified the following key elements which 
must be present in order for EPA to approve the 1-hour attainment 
demonstration SIPs. These elements are listed below and then described 
in detail.
    Clean Air Act measures, and other measures relied on in the modeled 
attainment demonstration SIP. This includes adopted and submitted rules 
for all previously required Clean Air Act mandated measures for the 
specific area classification. This also includes measures that may not 
be required for the area classification but that the State relied on in 
the SIP submission for attainment and ROP plans on which EPA is 
proposing to take action today.
NOX Reductions Affecting Boundary Conditions.
    Motor vehicle emissions budget. This must be a motor vehicle 
emissions budget which can be determined by EPA to be adequate for 
conformity purposes.
    Mid-course review. An enforceable commitment to conduct a mid-
course review and evaluation based on air quality and emission trends 
must be included in the attainment demonstration SIP before it can be 
approved by the EPA. The mid-course review would show whether the 
adopted control measures are sufficient to reach attainment by the 
area's attainment date, or that additional control measures are 
necessary.

[[Page 70518]]

1. Clean Air Act Measures and Measures Relied on in the Modeled 
Attainment Demonstration SIP
    The States should have adopted the control measures already 
required under the Clean Air Act for the area classification. Since 
these 10 serious and severe areas need to achieve substantial 
reductions from their 1990 emissions levels in order to attain, EPA 
anticipates that these areas need all of the measures required under 
the Clean Air Act to attain the 1-hour ozone NAAQS.
    In addition, the States may have included control measures in its 
attainment strategy that are in addition to measures required in the 
Clean Air Act. (For serious areas, these should have already been 
identified and adopted, whereas severe areas have until December 2000 
to submit measures to achieve ROP through the attainment year and to 
attain.) For purposes of fully approving the State's SIP, the State 
will need to adopt and submit all VOC and NOX controls 
within the local modeling domain that were relied on for purposes of 
the modeled attainment demonstration.
    The following table presents a summary of the Clean Air Act 
requirements that need to be met for each severe nonattainment area for 
the 1-hour ozone NAAQS. These requirements are specified in section 182 
of the Clean Air Act. Information on more measures that States may have 
adopted or relied on in their current SIP submissions is not shown in 
the table.

                    CAA Requirements for Severe Areas
 
 
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--NSR for VOC and NOX, including an offset ratio of 1.3:1 and a major
 VOC and NOX source cutoff of 25 tons per year (tpy)
--Reasonable Available Control Technology (RACT) for VOC and NOx
--Enhanced Inspection and Maintenance       (I/M) program
--15% VOC plans for ROP through 1996
--Emissions inventory
--Emission statements
--Attainment demonstration
--9% ROP plan through 1999
--Clean fuels program
--Enhanced monitoring (PAMS)
--Stage II vapor recovery
--Reformulated gasoline
--9% ROP plan through attainment year (post-1999)
--Measures to offset Vehicle Miles Travelled (VMT) growth
--Requirements for fees for major sources for failure to attain
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    2. NOX Reductions Consistent With the Modeling 
Demonstration
    The EPA completed final rulemaking on the NOX SIP call 
on October 27, 1998, which required States to address transport of 
NOX and ozone to other States. To address transport, the 
NOX SIP call established emissions budgets for 
NOX that 22 jurisdictions were required to meet through 
enforceable SIP measures adopted and submitted by September 30, 1999. 
The NOX SIP call is intended to reduce emissions in upwind 
States that significantly contribute to nonattainment problems. The EPA 
did not identify specific sources that the States must regulate nor did 
EPA limit the States' choices regarding where to achieve the emission 
reductions. Subsequently, a three-judge panel of the Court of Appeals 
for the District of Columbia Circuit issued an order staying the SIP 
submission requirement portion of the NOX SIP call rule 
requiring States to submit rules by September 30, 1999.
    The NOX SIP call rule establishes budgets for the States 
in which 9 of the nonattainment areas for which EPA is proposing action 
today are located. The 9 areas are: Greater Connecticut, Springfield, 
MA, New York/North New Jersey/Long Island (NY-NJ-CT), Baltimore, MD, 
Philadelphia/Wilmington/Trenton (PA-NJ-DE-MD), Metropolitan Washington, 
DC (DC-MD-VA), Atlanta, GA, Milwaukee-Racine WI, and Chicago-Gary-Lake 
County (IL-IN).
    Emission reductions that will be achieved through EPA's 
NOX SIP call will reduce the levels of ozone and ozone 
precursors entering nonattainment areas at their boundaries. For 
purposes of developing attainment demonstrations, States define local 
modeling domains that include both the nonattainment area and nearby 
surrounding areas. The ozone levels at the boundary of the local 
modeling domain are reflected in modeled attainment demonstrations and 
are referred to as boundary conditions. With the exception of Houston, 
the 1-hour attainment demonstrations on which EPA is proposing action 
have relied, in part, on the NOX SIP call reductions for 
purposes of determining the boundary conditions of the modeling domain. 
Emission reductions assumed in the attainment demonstrations are 
modeled to occur both within the State and in upwind States. Thus, 
intrastate reductions as well as reductions in other States impact the 
boundary conditions. Although the court has indefinitely stayed the SIP 
submission deadline, the NOX SIP Call rule remains in 
effect. Therefore, EPA believes it is appropriate to allow States to 
continue to assume the reductions from the NOX SIP call in 
areas outside the local 1-hour modeling domains. If States assume 
control levels and emission reductions other than those of the 
NOX SIP call within their States but outside of the modeling 
domains, the States must also adopt control measures to achieve those 
reductions in order to have an approvable plan.
    Accordingly, States in which the nonattainment areas are located 
will not be required to adopt measures outside the modeling domain to 
achieve the NOX SIP call budgets prior to the time that all 
States are required to comply with the NOX SIP call. If the 
reductions from the NOX SIP call do not occur as planned, 
States will need to revise their SIPs to add additional local measures 
or obtain interstate reductions, or both, in order to provide 
sufficient reductions needed for attainment.
    As provided in section 1 above, any controls assumed by State 
inside the local modeling domain 7 must be adopted as part 
of the State's 1-hour attainment demonstration SIP. It is only for 
NOX emission reductions occurring outside of the local 
modeling domain that States may assume implementation of the 
NOX SIP call measures and the resulting boundary conditions 
without actually being required at this time to adopt regulations to 
implement the NOX emission reductions required by the 
NOX SIP call.
---------------------------------------------------------------------------

    \7\ For the purposes of this notice, ``local modeling domain'' 
is typically an urban scale domain with horizontal dimensions less 
than about 300 km on a side, horizontal grid resolution less than or 
equal to 5 x 5 km or finer. The domain is large enough to ensure 
that emissions occurring at 8 am in the domain's center are still 
within the domain at 8 pm the same day. If recirculation of the 
nonattainment area's previous day's emissions is believed to 
contribute to an observed problem, the domain is large enough to 
characterize this.
---------------------------------------------------------------------------

3. Motor Vehicle Emissions Budget
    The EPA believes that an attainment demonstration SIP must 
necessarily estimate the motor vehicle emissions that will be produced 
in the attainment year and must demonstrate that this emissions level, 
when considered with emissions from all other sources, is consistent 
with attainment. The estimate of motor vehicle emissions is used to 
determine the conformity of transportation plans and programs to the 
SIP, as described by Clean Air Act section 176(c)(2)(A). For 
transportation conformity purposes, the estimate of motor vehicle 
emissions is known as the motor vehicle emissions budget. The EPA 
believes that an appropriately identified motor vehicle emissions 
budget is a necessary part of an attainment demonstration SIP. A SIP 
cannot effectively demonstrate

[[Page 70519]]

attainment unless it identifies the level of motor vehicle emissions 
that can be produced while still demonstrating attainment.
    The EPA has determined that, except for the Western MA 
(Springfield) attainment demonstration SIP, the motor vehicle emission 
budgets for the 9 other nonattainment areas covered in today's 
proposals are inadequate or missing from the attainment demonstrations. 
Therefore, EPA is proposing to disapprove the attainment demonstration 
SIPs for those 9 areas if the States do not submit motor vehicle 
emissions budgets that EPA can find adequate by May 31, 
2000.8 In order for EPA to complete the adequacy process by 
the end of May, States should submit an emissions budget no later than 
December 31, 1999.9 If an area does not have a motor vehicle 
emissions budget that EPA can determine adequate for conformity 
purposes by May 31, 2000, EPA plans to take final action at that time 
disapproving in full or in part the area's attainment demonstration. 
The emissions budget should reflect all of the motor vehicle control 
measures contained in the attainment demonstration, i.e., measures 
already adopted for the nonattainment area as well as those yet to be 
adopted.
---------------------------------------------------------------------------

    \8\ For severe areas, EPA will determine the adequacy of the 
emissions budgets associated with the post-1999 ROP plans once the 
States submit the target calculations, which are due no later than 
December 2000.
    \9\ A final budget is preferred; but, if the State public 
process is not yet complete, then a draft budget may be submitted. 
The adequacy process generally takes at least 90 days. Therefore, in 
order for EPA to complete the adequacy process no later than the end 
of May, EPA must have by February 15, 2000, the final budget or a 
draft that is substantially similar to what the final budget will 
be. The State must submit the final budget by April 15, 2000.
---------------------------------------------------------------------------

4. Mid-Course Review
    A mid-course review (MCR) is a reassessment of modeling analyses 
and more recent monitoring and emissions data to determine if a 
prescribed control strategy is resulting in emission reductions and air 
quality improvements needed to attain the ambient air quality standard 
for ozone as expeditiously as practicable but no later than the 
statutory attainment dates.
    The EPA believes that a commitment to perform a MCR is a critical 
element of the WOE determination for the attainment demonstration on 
which EPA is proposing to take action today. In order to approve the 
Indiana attainment demonstration SIP for the Chicago-Gary-Lake County 
area, EPA believes that Indiana must submit an enforceable commitment 
to perform a MCR as described here.10
---------------------------------------------------------------------------

    \10\ For purposes of conformity, the State needs a commitment 
that has been subject to a public hearing. If the State has 
submitted a commitment that has been subject to public hearing and 
that provides for the adoption of all measures necessary for 
attainment, the State should submit a letter prior to December 31, 
1999, amending the commitment to include the MCR.
---------------------------------------------------------------------------

    As part of the commitment, the State should commit to work with EPA 
in a public consultative process to develop a methodology for 
performing the MCR and developing the criteria by which adequate 
progress would be judged.
    For severe areas, such as the Chicago-Gary-Lake County ozone 
nonattainment area, the States must submit an enforceable commitment to 
perform the MCR immediately following the 2003 ozone season and to 
submit the results to EPA by December 31, 2003. EPA believes that an 
analysis in 2003 would be most robust since some or all of the regional 
NOX emission reductions should be achieved by that date. EPA 
would then review the results and determine whether any States need to 
adopt and submit additional control measures for purposes of 
attainment. The EPA is not requesting that States commit now to adopt 
new control measures as a result of this process. It would be 
impracticable for the States to make a commitment 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 
controls needed to ensure that an area attains the standard. Therefore, 
if EPA determines that additional control measures are needed for 
attainment, EPA would determine whether additional emission reductions 
are needed in the States in which the nonattainment areas are located 
or in upwind States, or in both. The EPA would require the affected 
State or States to adopt and submit new measures within a period 
specified at that time. The EPA anticipates that these findings would 
be made as calls for SIP revisions under section 110(k)(5) and, 
therefore, the period for submission of the measures would be no longer 
than 18 months after the EPA finding. A draft guidance document 
regarding the MCR process is located in the docket for this proposal 
and may also be found on EPA's web site at http://www.epa.gov/ttn/
scram/.

D. Additional Background Considerations for This Proposed Rulemaking

What Information Does the EPA Expect To Receive From the States To 
Allow an Approval of the 1-hour Ozone Attainment Demonstration SIPs?
    The following table shows a summary of information on what EPA 
expects from Indiana to allow EPA to approve the severe area 1-hour 
ozone attainment demonstration SIP for the Chicago-Gary-Lake County 
nonattainment area.

  Summary Schedule of Future State Actions--Severe Nonattainment Areas
     That Will Submit All Measures Needed for Attainment by 12/31/00
------------------------------------------------------------------------
   Required no later than:                       Action
------------------------------------------------------------------------
12/31/99.....................  State submits the following to EPA:
                                 --Motor vehicle emissions budget.\1\
                                 --Enforceable commitment to perform a
                                mid-course review.
4/15/00......................  State submits--
                                 --The final motor vehicle emissions
                                budget (only if draft submitted
                                earlier).\2\
                                 --Enforceable commitment (only if draft
                                submitted earlier) to perform a mid-
                                course review (only if draft submitted
                                earlier).
12/31/00.....................  --State submits a revised/final modeling
                                analysis.
                               --State submits adopted rules that
                                reflect measures relied on in modeled
                                attainment demonstration and that
                                support ROP requirements.
                               --State revises & submits SIP & motor
                                vehicle emissions budget if adopted
                                measures are for motor vehicle category.

[[Page 70520]]

 
12/31/03.....................  State submits to EPA results of mid-
                                course review.
------------------------------------------------------------------------
\1\ Final budget preferable; however, if public process is not yet
  complete, then a draft budget may be submitted at this time. Note that
  the budget can reflect estimated Tier 2 emission reductions--see
  memorandum from Lydia Wegman and Merrylin Zaw-Mon, ``1-Hour Ozone
  Attainment Demonstrations and Tier 2/Sulfur Rulemaking.''
\2\ If a final budget is significantly different from the draft
  submitted earlier, the final budget must be submitted by 2/15/00 to
  accommodate the 90 day processing period prior to the 5/31/00 date by
  which EPA must find the motor vehicle emissions budget adequate.

What Are the Relevant Policy and Guidance Documents?
    This proposal has cited several policy and guidance memoranda. The 
EPA has also developed several technical documents related to the 
rulemaking action in this proposal. Some of the documents have been 
referenced above. The documents and their location on EPA's web site 
are listed below; these documents will also be placed in the docket for 
this proposal action.
Recent Documents
    1. ``Guidance for Improving Weight of Evidence Through 
Identification of Additional Emission Reductions, Not Modeled.'' U.S. 
Environmental Protection Agency, Office of Air Quality Planning and 
Standards, Emissions, Monitoring, and Analysis Division, Air Quality 
Modeling Group, Research Triangle Park, NC 27711. November 1999. Web 
site: http://www.epa.gov/ttn/scram/.
    2. ``Serious and Severe Ozone Nonattainment Areas: Information on 
Emissions, Control Measures Adopted or Planned and Other Available 
Control Measures.'' Draft Report. November 3, 1999. Ozone Policy and 
Strategies Group. U.S. EPA, RTP, NC.
    3. Memorandum, ``Guidance on Motor Vehicle Emissions Budgets in 1-
hour Attainment Demonstrations,'' from Merrylin Zaw-Mon, Office of 
Mobile Sources to Air Division Directors, Regions I-VI, November 3, 
1999. Web site: http://www.epa.gov/oms/transp/traqconf.htm.
    4. Memorandum, ``1-Hour Ozone Attainment Demonstrations and Tier 2/
Sulfur/Sulfur Rulemaking,'' from Lydia Wegman and Merrylin Zaw-Mon to 
the Air Division Directors, Regions I-VI, November 8, 1999. Web site: 
http://www.epa.gov/oms/transp/traqconf.htm.
    5. Draft Memorandum, ``1-Hour Ozone NAAQS--Mid-Course Review 
Guidance.'' From John Seitz, Director, Office of Air Quality Planning 
and Standards. Web site: http://www.epa.gov/ttn/scram/.
Previous Documents
    1. U.S. EPA, (1991), Guideline for Regulatory Application of the 
Urban Airshed Model, EPA-450/4-91-013, (July 1991). Web site: http://
www.epa.gov/ttn/scram/ (file name: ``UAMREG'').
    2. U.S. EPA, (1996), Guidance on Use of Modeled Results to 
Demonstrate Attainment of the Ozone NAAQS, EPA-454/B-95-007, (June 
1996). Web site: http://www.epa.gov/ttn/scram/ (file name: ``O3TEST'').
    3. Memorandum, ``Ozone Attainment Demonstrations,'' from Mary D. 
Nichols, issued March 2, 1995. Web site: http://www.epa.gov/ttn/oarpg/
t1pgm.html.
    4. Memorandum, ``Extension of Attainment Dates for Downwind 
Transport Areas,'' issued July 16, 1998. Web site: http://www.epa.gov/
ttn/oarpg/t1pgm.html.
    5. December 29, 1997 Memorandum from Richard Wilson, Acting 
Assistant Administrator for Air and Radiation ``Guidance for 
Implementing the 1-Hour Ozone and Pre-Existing PM10 NAAQS.'' 
Web site: http://www.epa.gov/ttn/oarpg/t1pgm.html.

II. Technical Review of the Submittal

A. Summary of State Submittals

1. General Information
When Was the Attainment Demonstration Addressed in Public Hearings, and 
When was the Attainment Demnstration Submitted by the State of Indiana?
    The State held a public hearing on the ozone attainment 
demonstration on April 6, 1998 and submitted to it EPA on April 30, 
1998.
What Are the Basic Components of the Submittal?
    Since Indiana, along with Illinois, Michigan, and Wisconsin, 
participated in the Lake Michigan Ozone Study and the Lake Michigan 
Ozone Control Program, and since these ozone modeling studies form the 
technical basis for the ozone attainment demonstration, Illinois, 
Indiana, and Wisconin centered their ozone attainment demonstrations 
around a single technical support document (April 1998) produced by the 
four States in the Lake Michigan Air Directors Consortium (LADCO). This 
technical support document is entitled ``Modeling Analysis for 1-Hour 
Ozone NAAQS in the Lake Michigan Area.'' Each State has also included a 
state-specific cover letter and state-specific synopsis of the ozone 
attainment demonstration. It should be noted that the specifics of the 
emission control strategies considered varied by State. The specific 
emission categories or emission controls considered by Indiana are 
summarized below.
2. Modeling Procedures and Basic Input Data
What Modeling Approach Was Used in the Analyses?
    All three States, as members of LADCO and as participants in the 
Lake Michigan Ozone Study and Lake Michigan Ozone Control Program, used 
the same ozone modeling approach. The modeling approach is documented 
in an April 1998 technical support document, entitled ``Modeling 
Analysis For 1-Hour Ozone NAAQS In The Lake Michigan Area.'' Since the 
April 1998 technical support document failed to document all of the 
modeling approaches and bases for the development and selection of 
model input data, this review also relies on an older, December 1995, 
technical support document submitted by the LADCO States, which does a 
more thorough job of documenting the system and input data.
    The heart of the modeling system and approach is the Urban Airshed 
Model--Version V (UAM-V) developed originally for application in the 
Lake Michigan area. This photochemical model was used to model ozone 
and ozone precursors in a multiple, nested grid system. In the 
horizontal dimension, three nested grids were used. Grid A, the largest 
of the three grids, is a 35 cell by 50 cell grid (560 kilometers east-
west by 800 kilometers north-south) generally centered on the lower 
two-thirds of Lake Michigan with a horizontal resolution of 16 
kilometers per cell. Grid B is a 34 cell by 60 cell

[[Page 70521]]

grid (272 kilometers east-west by 480 kilometers north-south) centered 
on the lower three-quarters of Lake Michigan with a horizontal 
resolution of 8 kilometers per cell. Grid B covers all of the 1-hour 
ozone nonattainment areas of interest in the analysis. Grid C is a 20 
cell by 80 cell grid (80 kilometers east-west by 320 kilometers north-
south) approximately centered on the western shoreline of lower Lake 
Michigan with a horizontal resolution of 4 kilometers per cell. The 
model covered 8 vertical layers over the entire horizontal modeling 
domain. Mixing heights used in the modeling system were determined from 
regional upper-air monitoring station data.
    Besides being able to model ozone and other pollutants in nested 
horizontal grids, UAM-V can also model individual elevated source 
plumes within the modeling grid (plume-in-grid or PiG). Gaussian 
dispersion models are used to grow plumes until the plumes essentially 
filled grid cells. At these points, the numerical dispersion and 
advection components of UAM take over to address further downwind 
dispersion and advection.
    The UAM-V modeling system is also used to assess the impacts of 
clouds on certain high ozone episode days. Observed cloud data are used 
to modify chemical photolysis rates and other meteorological input 
data.
    The following input data systems and analyses were also used as 
part of the combined modeling system for the Lake Michigan area:
    a. Emissions. UAM-V requires the input of gridded, hourly estimates 
of CO, NOX, and speciated VOC emissions (speciated based on 
carbon bond types). The States provided emission inventories, which 
were processed through the Emissions Modeling System--1995 version 
(EMS-95) to prepare UAM-V input data files. Emission data files were 
generated for Grid A and Grid B.
    For Grid B, the States supplied point source (individually 
identified stationary sources) and area source (sources too small and 
numerous to be identified and recorded as individual sources) emissions 
for a typical summer weekday. These emissions were based on the States' 
1990 base year emissions inventories for the ozone nonattainment areas 
and were adjusted to 1991 levels to be compatible with the high ozone 
periods modeled. The base emissions were adjusted for some source 
categories to reflect typical ``hot summer days.'' Day-specific 
emissions data were supplied by over 200 facilities in the modeling 
domain. Mobile source emissions were calculated by EMS-95 using 
MOBILE5a (a mobile source emissions model supplied by the EPA) emission 
factors (using day-specific temperatures) and local vehicle-miles-
traveled data generally supplied by local metropolitan planning 
agencies and based on transportation models. Finally, the biogenic 
emission rates used in Grid B were calculated based on BIOME, which is 
the biogenics emissions model contained within EMS-95.
    For Grid A, point and area anthropogenic emissions rates were 
derived from EPA's 1990 Interim Regional Inventory, except for 
Wisconsin, which supplied state-specific data. Mobile source emissions 
were based on MOBILE5a emission factors (derived for a representative 
hot summer day) and vehicle miles traveled data derived using the 1990 
Highway Performance Monitoring System. Biogenic emission rates were 
calculated using the Biogenics Emissions Inventory System (BEIS) 
assuming temperatures for a representative, hot summer day. This 
version of BEIS includes soil NOX emissions and land use 
data from the United States Geological Survey.
    Grid B emissions data superceded Grid A data within Grid B. Grid C 
emissions data were not specifically derived--Grid B emissions data 
were used within Grid C.
    All emission estimates were speciated by compound or carbon bond 
type and spatially, and temporally resolved into UAM-V input data files 
by the use of EMS-95.
    b. Meteorology. Meteorological input data by grid cell and hour 
were generated by use of a prognostic meteorological model (model 
output data derived from equations which describe how meteorological 
variables, such as wind speed/direction, temperature, and water vapor 
change over time) known as CALRAMS. CALRAMS was run with varying 
horizontal resolution depending on location. Over Grids B and C, 
CALRAMS was run with 4 kilometer resolution. Over Grid A, a resolution 
of 16 kilometers was used. Over the remainder of the continental United 
States, a resolution of 80 kilometers was used. The model's vertical 
structure used 31 layers in Grid A and over the remainder of the 
continental United States outside of the UAM-V modeling domain and 26 
layers over Grids B and C.
    Four-dimensional data assimilation using observed meteorological 
data values was used to ensure that the model estimates did not deviate 
significantly from observed meteorological data. Preprocessor programs 
were used to map the model's output data into the UAM-V grid system and 
to derive other necessary model inputs.
    Some adjustments were made to CALRAMS results where the model 
produced near-calm wind speeds and where observed wind speeds were 
significantly higher than modeled wind speeds during one modeled ozone 
episode.
    c. Chemistry. Atmospheric chemistry within the modeling grid system 
and UAM-V was simulated using the Carbon Bond-Version IV model 
developed by the Environmental Protection Agency and used in Version IV 
of UAM.
    d. Boundary and Initial Conditions. Initial sensitivity analyses of 
the modeling system's response to modeling domain boundary conditions 
(incoming ozone and ozone precursor levels at the outer edges of the 
modeling domain) showed that the system was very sensitive to these 
boundary conditions. LADCO used all available upwind data, and 
especially those collected during the 1991 intensive field study, to 
derive boundary conditions. In addition, the contractor, SAI, 
Incorporated, used output data from the use of the Regional Oxidant 
Model (ROM) to derive initial concentrations in the modeling domain for 
the first day of each modeled ozone episode. Data from this first day, 
along with other model input data, were used to model ozone and 
precursor concentrations for the next 1 to 2 days, to be used as inputs 
into the main part of the modeled ozone episode. The first 1 to 2 days 
modeled were treated as ``ramp-up days'' for the main part of each 
modeled ozone episode. This process produced more stable input data for 
the modeling of high ozone days.
What High Ozone Periods Were Modeled?
    Four high ozone episodes in 1991 were considered. These episodes 
were:

June 18-21, 1991;
June 24-28, 1991;
July 15-19, 1991; and
August 22-26, 1991.

    The 1991 ozone episodes were selected as the focus of the modeling 
analyses because the summer of 1991 was a relatively conducive period 
for ozone formation, and, most importantly, because LADCO conducted an 
intensive field study during that summer to collect data needed to 
support the modeling study.

[[Page 70522]]

What Procedures and Sources of Projection Data Were Used To Project the 
Emissions to Future Years?
    The future year emission inventories used in the Lake Michigan 
Ozone Control Program and ozone attainment demonstration were derived 
from the Lake Michigan Ozone Study base year regional inventory 
(discussed above). Three adjustments were made to the base year 
emissions inventory to generate the future year emission inventories. 
First, a baseline inventory was prepared by replacing the day-specific 
emissions with typical hot summer day emissions for point sources. 
Emissions for other source categories were simply carried over to the 
baseline inventory. Second, the baseline emissions inventory was 
projected to 2007 (the attainment year for severe ozone nonattainment 
areas) by applying scalar growth factors. Finally, the projected 
baseline emission inventories were reduced to reflect the 
implementation of various emission control measures expected or 
required to occur by those years.
    The growth factors used in the projection of emissions for each 
source sector are as follows:
    a. Point Sources. i. For electric utilities--company-specific data 
were provided by each State;
    ii. For certain individual point sources--a growth factor of ``0'' 
was used to reflect the shutdown of these sources;
    iii. For all remaining point source emission categories--growth 
factors based on the EPA Economic Growth Analysis System (EGAS) were 
used;
    b. Area Sources. i. For baseline emission estimates based on 
population--projected populations were used to recalculate emissions;
    ii. For gasoline marketing source categories--projected emissions 
were based on projected gasoline sales;
    iii. For other area source emission categories--projections were 
based on EGAS estimates (some EGAS estimates were judged to be 
inappropriate and alternative surrogates were used to estimate future 
emissions);
    c. Mobile Sources. Vehicle miles traveled projections were based on 
transportation modeling for northeast Illinois, northwest Indiana, and 
southeast Wisconsin, and on State-supplied growth factors for the rest 
of the ozone modeling domain; and
    d. Biogenic Sources. No growth was assumed.
    To account for emission changes resulting from various emission 
controls (these emission controls also affect projected emissions), the 
States tested several emission control strategies. Emission reduction 
scalars were developed to reflect the expected or required emission 
reduction levels, rule penetration (accounting for the percentage of 
source category emissions affected by the emission reduction 
requirements), and rule effectiveness (some source control rules do not 
fully achieve the emission reductions expected due to control device 
failure, human error, or other factors). The base component of these 
control strategies were the emission reductions resulting from the 
controls mandated by the Clean Air Act and expected to be in place by 
2007. These emission controls are further discussed below.
How Were the Emissions, Air Quality, and Meteorological Input Data 
Quality Assured?
    Emissions. The Lake Michigan States' quality assurance of the 
emissions data focused on the comprehensiveness and reasonableness of 
the emissions data rather than on precision and accuracy of the data. 
During the initial development of the regional emissions inventory, 
internal quality control activities included the preparation and 
implementation of quality assurance plans for the derivation of 
emission estimates by each State and for the development and 
application of the EMS-95 emissions software. External quality 
assurance activities included: (1) Audits of the point and area source 
data inputs; (2) review of the EMS-95 output; and (3) independent 
testing of the EMS-95 model source code. The State emission estimates 
were compared against each other to assess their completeness, 
consistency, and reasonableness.
    Several approaches were used to compare the emission estimates 
against ambient measurements. These included: (1) Comparisons of 
ambient to emissions-based ratios of non-methane organic compounds to 
oxides of nitrogen; (2) comparisons of ambient to emissions-based 
ratios of carbon monoxide to oxides of nitrogen; (3) receptor modeling 
(determining individual source shares of monitored pollutant 
concentrations based on source-specific emission profiles and temporal 
and spatial statistical analyses of monitored pollutant species); and 
(4) comparisons of ambient to model-based ratios of non-methane organic 
compounds to oxides of nitrogen. The comparison of the measurement-
based pollutant ratios with the emissions inventory-based pollutant 
ratios showed good agreement between the emissions inventory and the 
ambient data. The receptor modeling results also generally supported 
the validity of the emissions inventory.
    Air Quality and Meteorological Data. Validation of the 1991 Lake 
Michigan Ozone Study field data (the data used as input to the 
meteorological and photochemical dispersion models and used to validate 
the models' outputs) was performed by the Lake Michigan Ozone Study 
Data Management and Data Analysis Contractors. The data were validated 
using a number of statistical analyses. Three levels of validation were 
used, depending on the intended use of the data. The three levels of 
data validation were:
    a. Level 1. This validation was performed by the group collecting 
the data. This group: flagged suspect data values; verified the data 
contained in computer data files against input data sheets; eliminated 
invalid measurements; replaced suspect data with data from back-up data 
acquisition systems; and adjusted measurement values to eliminate 
quantifiable calibration and interference biases;
    b. Level 2. This validation was performed on data assembled in a 
master data base. The level of data validation involved various 
consistency checks between data values within the data base, including: 
comparison of data from closely located sites collected at 
approximately the same time; comparison of data from co-located 
sampling systems; comparisons based on physical relationships; and 
special statistical analyses of the VOC and carbonyl data; and
    c. Level 3. This validation was performed by the Lake Michigan 
Ozone Study Data Analysis Contractor and was performed as part of the 
data interpretation process. This validation included identification of 
unusual data values (e.g. extreme values, values which fail to track 
the values of other associated data in a time series, or those values 
which did not appear to fit the general and spatial or temporal overall 
pattern).
    As a result of the data validation, several changes were made to 
the meteorological and air quality input data. Volume III (December 
1995) of the Lake Michigan Ozone Study/Lake Michigan Ozone Control 
Program Project Report documents all of the data changes resulting from 
the data validation efforts.

3. Modeling Results

How Did the States Validate the Photochemical Modeling Results?
    A protocol document outlining the operational and scientific 
evaluation of the modeling system was prepared by

[[Page 70523]]

LADCO, and was approved by the Environmental Protection Agency on March 
6, 1992. The evaluation of the photochemical model consisted of seven 
steps:
    a. Evaluation of the scientific formulation of the model by the 
Photochemical Modeling Contractor;
    b. Assessment of the fidelity of the computer codes to scientific-
formulation, governing equations, and numerical solution procedures 
performed by an independent contractor (independent of the 
Photochemical Modeling Contractor);
    c. Evaluation of the predictive performance of the individual 
modeling process modules and preprocessor modules to identify possible 
flaws or systematic biases;
    d. Evaluation of the full model's predictive performance against 
statistical performance tests and performance criteria specified by the 
EPA (see discussion of the model's performance for specific days 
modeled below);
    e. Performance of sensitivity tests to assure conformance of the 
model with known or expected model behavior;
    f. Performance of comparative modeling analyses, comparing the 
results from the use of UAM-V with similar results from the use of UAM-
IV (the photochemical model generally recommended by the Environmental 
Protection Agency); and
    g. Implementation of quality control and quality assurance 
activities, including: (i) Benchmark modeling; (ii) pre-established 
file structuring; (iii) duplicative modeling; (iv) modeling procedure 
and results documentation; and (v) external review of modeling results.
    Numerous modeling runs and overall system evaluations were 
conducted to carry out these validation procedures.
What Were the Results of the Model Performance Evaluations for the 
Modeling System Used in the Attainment Demonstration?
    The following highlights the results of the operational and 
scientific evaluation of the modeling system. These results are 
discussed in detail in many documents generated by LADCO and supplied 
to the Environmental Protection Agency:
    a. Many modeling runs and evaluations of output data were made to 
derive statistical results indicative of the modeling system's overall 
performance. Statistical data, such as: observed peak ozone 
concentrations versus peak predicted concentrations; unpaired peak 
concentration accuracy; bias in peak concentrations and overall system 
bias; and gross system error, were compared to acceptable system 
criteria specified by the EPA (Guideline for Regulatory Application of 
the Airshed Model, EPA-450/4-91-013, July 1991). The statistical 
accuracy results for the modeling system comply with the EPA 
performance criteria;
    b. The spatial and temporal representation of the surface ozone 
concentrations are reasonable both region-wide and in the areas of high 
concentrations. Broad areas of high ozone concentrations were 
reproduced successfully and magnitude and times of peak ozone 
concentrations reasonably matched those observed;
    c. Model performance across the full modeling domain was consistent 
with model performance in individual subregions. This further supports 
the credibility of the modeling system;
    d. Predicted aloft downwind ozone concentrations compare favorably 
with airborne/aircraft monitored ozone concentrations. This supports 
the three-dimensional validity of the modeling system; and
    e. Model performance for ozone precursors, especially for 
NOX, was very good. This further supports the validity of 
the use of the model to evaluate the impacts on ozone due to changes in 
precursor emissions and the testing of the emission control strategy 
scenarios.
    Based on the model performance evaluation results, the EPA approved 
the validity of the modeling system and its use for control strategy 
evaluations on December 15, 1994 (letter from John Seitz, Director of 
the Office of Air Quality Planning and Standards to Lake Michigan Air 
Directors Consortium).
What Were the Ozone Modeling Results for the Base Period and for the 
Future Attainment Period?
    Many modeling runs were conducted, producing millions of model 
output data. What is summarized in Tables 1 and 2 are the observed and 
modeled peak ozone concentrations for the selected ozone episode days 
for two considered emission control strategies. Please note that the 
ozone control strategy covered by each table is further discussed 
below.
    The ozone modeling system was run to simulate ozone concentrations 
on selected high ozone days for the base year and future year (2007). 
The future year simulations covered five boundary condition scenarios, 
corresponding to base year boundary conditions, and to the reduction of 
peak boundary ozone levels to 85, 80, 70, and 60 parts per billion 
(ppb), 1-hour average. The future year simulations also covered two 
emission control strategy sets, Strategy 2 and Strategy 4.
    The resulting domain-wide modeled peak ozone concentrations for 
Strategy 2 are given in Table 1. Similarly, the resulting domain-wide 
modeled peak ozone concentrations for Strategy 4 are given in Table 2.

                                     Table 1.--Lake Michigan Ozone Control Program Strategy 2 Ozone Modeling Results
                                                      [Domain-wide Peak Ozone Concentrations, ppb]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        2007  85     2007  80     2007  70     2007  60
                          1991  Date                            1991  OBS    1991  MOD   2007  BY BC      ppb          ppb          ppb          ppb
--------------------------------------------------------------------------------------------------------------------------------------------------------
June 26......................................................          175          165          141          134          133          128          122
June 27......................................................          118          152          130          123          122          119          114
June 28......................................................          138          142          123          118          118          116          109
June 20......................................................          152          137          123          121          121          120          120
June 21......................................................          134          126           --           --           --           --          114
July 17......................................................          145          148          133          126          124          120          113
July 18......................................................          170          162          146          135          135          128          119
July 19......................................................          170          161          145          137          137          129          119
Aug 25.......................................................          148          128          126          121          120          116          109
Aug 26.......................................................          189          158          142          135          131          124          115
--------------------------------------------------------------------------------------------------------------------------------------------------------
OBS = Observed Peak Ozone Concentration.
MOD = Modeled Base Year Peak Ozone Concentration.
BY BC = Base Year Boundary Conditions.
85 ppb, 80 ppb, 70 ppb, 60 ppb = Future Year Peak Ozone Boundary Concentrations.


[[Page 70524]]


                                     Table 2.--Lake Michigan Ozone Control Program Strategy 4 Ozone Modeling Results
                                                      [Domain-wide Peak Ozone Concentrations, ppb]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        2007  85     2007  80     2007  70     2007  60
                          1991  Date                            1991  OBS    1991  MOD   2007  BY BC      ppb          ppb          ppb          ppb
--------------------------------------------------------------------------------------------------------------------------------------------------------
June 26......................................................          175          165          137          130          129          124          117
June 27......................................................          118          152          125          117          117          114          109
June 28......................................................          138          142          119          114          114          112          104
June 20......................................................          152          137          117          117          117          117          116
June 21......................................................          134          126          121          118          117          115          110
July 17......................................................          145          148          132          123          121          116          110
July 18......................................................          170          162          141          131          129          123          115
July 19......................................................          170          161          140          131          129          123          114
Aug 25.......................................................          148          128          125          120          119          115          108
Aug 26.......................................................          189          158          139          133          129          122          113
--------------------------------------------------------------------------------------------------------------------------------------------------------
OBS = Observed Peak Ozone Concentration.
MOD = Modeled Base Year Peak Ozone Concentration.
BY BC = Base Year Boundary Conditions.
85 ppb, 80 ppb, 70 ppb, 60 ppb = Future Year Peak Ozone Boundary Concentrations.

Do the Modeling Results Demonstrate Attainment of the Ozone Standard?
    The modeling of the Strategy 2 and Strategy 4 impacts by themselves 
(the 2007 BY BC columns in Tables 1 and 2) does not demonstrate 
attainment. The modeling supports the need for significant reductions 
in background ozone and ozone precursor concentrations. In addition, 
the model indicates the potential for ozone exceedances or ozone 
standard violations under the scenarios of smaller reductions in 
background ozone levels. Nonetheless, when considered along with a WOE 
determination, as discussed below, the EPA believes that the modeling 
results do support a conclusion that local VOC emission reductions 
combined with possible transported ozone reductions can lead to 
attainment of the 1-hour ozone standard in the Chicago-Gary-Lake County 
ozone nonattainment area and its downwind environs.
Does the Attainment Demonstration Depend on Future Reductions of 
Regional Emissions?
    As noted in the tables summarizing the peak modeled ozone 
concentrations above and in the discussion elsewhere in this proposed 
rulemaking, the States considered emission control strategies which by 
themselves would not achieve attainment of the 1-hour ozone standard. 
The States, however, also show that, with a significant reduction in 
background ozone concentrations expected to result from the 
implementation of regional NOX emission controls under the 
NOX state implementation plan call, attainment of the 
standard can be achieved using the control strategies considered. 
Strategy 2 can lead to attainment of the ozone standard with a future 
reduction in peak ozone background concentrations down to 70 ppb. 
Strategy 4 can lead to attainment if peak background ozone 
concentrations are reduced to 80 ppb. LADCO documents that these future 
ozone background concentration levels may be obtained through the 
implementation of the NOX SIP call.
    It should be noted that LADCO not only considered lowered 
background ozone concentrations resulting from regional upwind emission 
controls, they also considered reductions in background ozone precursor 
concentrations. The States used various analyses to estimate the 
reductions in background ozone precursor concentrations associated with 
the assumed reductions in background ozone concentrations. This was 
primarily accomplished by considering available modeling data from 
OTAG.
    The following two step process was used to determine which of the 
tested boundary conditions correspond best to the boundary conditions 
that would be expected under the EPA NOX SIP call:
    a. The NOX emissions of the OTAG modeling domain were 
compared to the regional NOX emissions expected under the 
NOX SIP call. Several emission control strategies considered 
in the OTAG process were assessed. It is noted that the attainment 
demonstration's NOX emissions fall between OTAG emission 
control strategy runs C and H; and
    b. The boundary ozone concentration changes resulting from the 
selected OTAG strategy runs were then compared to the ozone boundary 
changes considered in the Lake Michigan Ozone Control Program modeling 
runs. The reduction of peak background ozone levels down to 70 ppb in 
the Lake Michigan Ozone Control Program was found to correspond best 
with the expected ozone changes considered under the selected OTAG 
emission control strategy runs C through H.
    Based on this approach, it is assumed that the NOX SIP 
call would reduce peak background ozone levels to 70 ppb.

4. Application of Attainment Test and the Attainment Demonstration

What Approach Was Used To Demonstrate Attainment of the Ozone Standard?
    To assess attainment of the 1-hour ozone standard, LADCO applied 2 
approaches to review the results of emission control strategy modeling, 
supplementing them with modeling results from the OTAG process. First, 
the States considered the modeling results through the use of a 
deterministic approach, and second, the States considered a statistical 
approach.
    a. Deterministic Approach. The deterministic approach to ozone 
attainment demonstrations, as defined in the Guidance on the Use of 
Modeled Results to Demonstrate Attainment of the Ozone NAAQS (June 
1996), requires the daily peak 1-hour ozone concentrations modeled for 
every grid cell (in the surface level) to be at or below the ozone 
standard for all days modeled. If there are modeled ozone standard 
exceedances in only a few grid cells on a limited number of days, this 
approach can still be used to demonstrate attainment of the ozone 
standard through the use of weight of evidence determinations.
    The States note that the deterministic test is passed for:
    i. Strategy 2 with future (2007) ozone boundary concentrations 
capped at 60 ppb; or
    ii. Strategy 4 with future ozone boundary concentrations capped at 
70 ppb.
    Note that Strategy 2 with a future ozone boundary concentration of 
70 ppb

[[Page 70525]]

or Strategy 4 with a future ozone boundary concentration of 80 ppb 
produces peak ozone concentrations that may demonstrate attainment 
given the supporting weight of evidence analysis. The modeling results 
for other Strategy 2 and Strategy 4 scenarios with higher ozone 
boundary concentrations, however, do not appear to be close enough to 
the standard to warrant the consideration of weight of evidence.
    b. Statistical Approach. The States note that the statistical 
approach permits occasional ozone standard exceedances and reflects an 
approach comparable to the form of the 1-hour ozone standard. 
Therefore, the States have also given this approach some attention.
    Under the statistical approach, there are three benchmarks related 
to the frequency and magnitude of allowed exceedances and the minimum 
level of air quality improvement after emission controls are applied. 
All three benchmarks must be passed in the statistical approach, or if 
one or more of the benchmarks are failed, the attainment demonstration 
must be supported by a weight of evidence analysis.
i. Limits on the Number of Modeled Exceedance Days
    This benchmark is passed when the number of modeled exceedances 
days in each subregion is less than or equal to 3 or N-1 (N is the 
number of severe days), whichever is less. To determine the number of 
severe days, the States concluded that a day is severe if there are at 
least two nonattainment areas within the modeling domain with observed 
1-hour peak ozone concentrations greater than the corresponding ozone 
design value (generally the fourth highest daily peak 1-hour ozone 
concentration at a monitor during a three year period) during the 1990 
through 1992 period. The States conclude that only two modeled days, 
June 26 and August 26, 1991, are severe ozone days. Therefore, N is 2.
    Based on a review of the modeled daily peak ozone concentrations, 
the States conclude that Strategy 2 with a maximum background ozone 
concentration of 60 ppb and Strategy 4 with a maximum background ozone 
concentration of 70 ppb would clearly pass this benchmark test. They 
also conclude that Strategy 2 with a future maximum background ozone 
concentration of 70 ppb and Strategy 4 with a maximum background ozone 
concentration of 80 ppb would also pass the benchmark based on an 
additional WOE analysis. The WOE analysis is based on the following 
evidence:
A. Factors Providing Confidence in Modeled Results
    Evaluation of the modeling system's performance shows that:
     Statistical measures for ozone comply with EPA's model 
performance criteria;
     Spatial and temporal patterns of monitored surface ozone 
concentrations are reproduced well by the modeling system on most days;
     Model performance for ozone across the full domain is 
consistent with the model performance in individual subregions;
     Aloft ozone predictions compare favorably with aircraft 
ozone data; and
     Model performance for ozone precursors, especially 
NOX, is very good.
    Confidence in underlying data bases is high. A comprehensive field 
program was conducted during the summer of 1991. This field program was 
used to collect a large quantity of air quality and meteorological data 
to support the photochemical grid modeling.
    The modeling results obtained by the LADCO States were corroborated 
with the results from other modeling studies. As part of the 
Cooperative Regional Model Evaluation (CReME), the photochemical models 
UAM-IV, UAM-V, and SAQM were applied in the Lake Michigan region. The 
supplemental analyses show that UAM-V produces results directionally 
consistent with those produced by UAM-IV and SAQM. All three models 
concurred in showing that VOC emission reductions are generally locally 
beneficial and that local NOX emission controls are not 
beneficial in certain locations, generally within 100 to 200 kilometers 
downwind of Chicago.
B. Severity of Modeled Episodes
    Three of the four ozone episodes modeled reflect meteorological 
conditions which typically favor high ozone in the Lake Michigan area 
(when the Lake Michigan area is on the ``back-side'' of a high pressure 
system with warm temperatures, high humidity, and south-southwesterly 
winds). The fourth episode is representative of warm temperatures with 
easterly winds, conditions which generally produce lower peak ozone 
concentrations and fewer ozone standard exceedances on a per year 
basis.
    The magnitudes of the observed peak ozone concentrations at one or 
more locations within the modeling domain for the selected ozone 
episodes exceed the corresponding ozone design values for many 
locations within the region. This implies that the modeled ozone 
episodes are conservative and that attaining the ozone standard for 
these episodes should lead to attainment of the ozone standard in non-
modeled episodes and during most future ozone conducive periods.
C. Trends Analyses
    Several trends analyses have been considered. First, 10-year trends 
established by the EPA based on second high daily maximum 1-hour ozone 
concentrations for each year show no significant changes in Chicago, 
Grand Rapids, Gary, and Kenosha; and a downward trend in Racine and 
Milwaukee. Second, 17-year trends based on the number of ozone 
exceedance days normalized based on the annual number of hot days show 
that the number of exceedance days is significantly decreasing relative 
to the number of hot days each year. Third, 15-year trends show 
downward trends in ozone at monitoring sites.
    Examination of limited morning total non-methane hydrocarbon 
concentration levels in Chicago and Milwaukee over the past 10 years 
show a significant downward trend. This downward trend is consistent 
with the calculated downward trend in VOC emissions.
    The LADCO States conclude that the weight of evidence demonstration 
provides additional information which verifies the directionality of 
the modeling and demonstrates the potential stringency of the modeling 
results. The States conclude this information is sufficient to support 
minor exceptions to the benchmark, supporting a demonstration of 
attainment at the higher background ozone concentrations.
ii. Limits on the Values of Allowed Exceedances
    Under this benchmark, the maximum modeled ozone concentration on 
severe days shall not exceed 130 ppb. The States, based on the modeled 
peak ozone concentrations, conclude this benchmark is passed for 
Strategy 2 with a maximum background ozone concentration of 70 ppb and 
for Strategy 4 with a maximum background ozone concentration of 80 ppb.
iii. Required Minimum Level of Air Quality Improvement
    Under this benchmark, the number of grid cells with modeled peak 
ozone concentrations greater than 124 ppb must be reduced by at least 
80 percent on each day with allowed modeled ozone standard exceedances. 
The States, based on the modeled peak ozone concentrations, conclude 
that this

[[Page 70526]]

benchmark is passed for Strategy 2 with a maximum background ozone 
concentration of 80 ppb and for Strategy 4 with a maximum background 
ozone concentration of 80 ppb.
    From the above, it can be seen that benchmark i. is the most 
stringent of benchmarks in this case. Based on the statistical 
approach, coupled with a WOE analysis, the States conclude that 
Strategy 2 with a maximum background ozone concentration of 70 ppb or 
Strategy 4 with a maximum background ozone concentration of 80 ppb is 
sufficient to attain the 1-hour ozone standard by 2007.
    The States further conclude, based on both attainment demonstration 
approaches, that either Strategy 2 or Strategy 4 coupled with future 
year boundary conditions generally consistent with the impacts of the 
NOX SIP call is sufficient to attain the 1-hour ozone 
standard. The States, however, note that reliance on the impacts of the 
NOX SIP call cannot be construed as concurrence on the part 
of the States with the substance of the NOX SIP call itself. 
Indiana has not committed to comply with the requirements of the 
NOX SIP call.
5. Emission Control Strategies
What Emission Control Strategies Were Considered in the Attainment 
Demonstrations?
    LADCO selected two emission control strategies considered during 
the Lake Michigan Ozone Control Program for further attainment 
demonstration modeling (numerous emission control measures were 
initially examined). The two strategies selected are referred to as 
Strategy 2 and Strategy 4. These emission control strategies would 
apply to the ozone nonattainment areas only and are summarized as the 
following:
    a. Strategy 2. Strategy 2 includes all national emission control 
measures (federal controls) mandated by the 1990 Clean Air Act, as 
amended in 1990, to be in place by 2007 and the State emission controls 
mandated to be in place by 1996, including the emission controls needed 
to comply with the requirements for 15 percent ROP plans. Additional 
ROP plans and State emission controls for the post-1996 period were not 
considered, and additional NOX emission controls, such as 
NOX Reasonably Available Control Technology (RACT), were not 
considered due to the existence of an approved NOX emission 
control waiver under section 182(f) of the Clean Air Act. Existing 
NOX emission reduction requirements, such as the acid rain 
control requirements under Title IV of the Clean Air Act, were 
considered.
    b. Strategy 4. Strategy 4 includes all Strategy 2 measures and also 
includes some additional point, area, and mobile source control 
measures in the severe ozone nonattainment areas. The additional 
controls are measures that the State could consider. The State, 
however, has not evaluated the technical feasibility or cost-
effectiveness of these measures. The measures have only been considered 
regarding their potential to reduce VOC and NOX emissions by 
2007. For the additional measures considered, please see Table 4.
    Table 3 lists the VOC and NOX emission reductions 
expected in Grid B and in the severe ozone nonattainment areas. 
Emissions control strategy components for Indiana considered in the 
attainment strategy modeling are listed in Table 4. The following 
acronyms are used:

RACT--Reasonably Available Control Technology
NESHAP--National Emission Standard for Hazardous Air Pollutants
MACT--Maximum Available Control Technology
I/M--Vehicle Inspection and Maintenance.

      Table 3.--Emission Control Levels From Strategies 2 and 4 Grid B and Severe Ozone Nonattainment Areas
                                      [Lake Michigan Ozone Modeling Domain]
----------------------------------------------------------------------------------------------------------------
                                                                VOC                             VOC
                                                 ---------------------------------------------------------------
                                                                                                      Severe
                                                      Grid B                                       nonattainment
                    Strategy                          percent                                          area
                                                     emission           NOX             NOX         percentage
                                                      change                                         emissions
                                                                                                      change
----------------------------------------------------------------------------------------------------------------
2...............................................             -27             -13             -37             -11
4...............................................             -40             -19             -53             -18
----------------------------------------------------------------------------------------------------------------


             Table 4.--Emission Control Measures for Indiana
 
 
-------------------------------------------------------------------------
            STRATEGY 2--2007 MANDATORY CLEAN AIR ACT MEASURES
------------------------------------------------------------------------
 
POINT SOURCE VOC CONTROLS
    Batch Processes RACT
    Industrial Wastewater RACT
    Marine Vessel Volatile Organic Liquid Loading Controls
    Metal Coil Coating Controls Tightening
    Paper Coating Controls Tightening
    Synthetic Organic Chemical Manufacturing Industry Reactor Processes
    Wood Parts Coating
    Coke Oven NESHAP
    Large Gasoline Storage
    Metal Can Coating Controls Tightening
    Offset Lithography
    Plastic Parts Coating Controls Tightening
    Volatile Organic Liquid Storage RACT
    Plant Shutdowns (Inland Steel Coke Batteries, Gary Incinerator, and
     Some Processes at Keil Chemical)
POINT SOURCE NOX CONTROLS
    Phase I Acid Rain NOX Limits
AREA SOURCE VOC CONTROLS

[[Page 70527]]

 
    Automobile Refinishing
    Architectural and Industrial Maintenance Coatings
    Marine Vessel Volatile Organic Loading
    Municipal Waste Landfills
    Open Burning Ban
    Gasoline Tank Truck Leak Reductions (due to use of reformulated
     gasoline)
    Stage I Refueling Reductions (due to use of reformulated gasoline)
    Stage II Refueling Vapor Recovery
    Underground Storage Tank Breathing Losses and Leaks (due to use of
     reformulated gasoline and improved valves)
    Commercial/Consumer Solvent Reformulation or Elimination
    Off-Road Engine Standards
    On-Board Vehicle Controls
MOBILE SOURCE CONTROLS
    Tier I Light-Duty Vehicle Standards
    Reformulated Gasoline--Phase II (Class C)
    Enhanced I/M (no NOX cut-points)
    Clean Fuel Fleets
    Current Transportation Improvement Program/Build Scenario
    Northwest Indiana Regional Transportation Plan, including the
     following elements:
        * Programs For Improved Public Transit
        * Employer-Based Transportation Management Plans
        * Traffic Flow Improvement Programs
        * Fringe and Transportation Corridor Parking Facilities Serving
         Multiple Occupancy Vehicle Programs
        * Programs for Secure Bicycle Storage Facilities and Other
         Bicycle Programs, including Bicycle Lanes
------------------------------------------------------------------------
 
                STRATEGY 4--2007 MANDATORY MEASURES PLUS
------------------------------------------------------------------------
 
All Strategy 2 measures plus:
POINT SOURCE VOC CONTROLS
    Improved Rule Effectiveness
    Phased Emission Reduction Program
AREA SOURCE VOC CONTROLS
    Agricultural Pesticides Application Controls
    Degreasing Controls
    Graphic Arts
    Improved Rule Effectiveness
    Petroleum Dry Cleaning Regulations
    Small Engine Buy-Back Program
POINT SOURCE NOX CONTROLS
    Phase II Acid Rain NOX Limits
MOBILE SOURCE CONTROLS
    California Low Emission Vehicle Controls
    Specific Vehicle I/M (no NOX cut-points)
    Reformulated Gasoline--Phase II (Class B)
------------------------------------------------------------------------

Has the State Adopted a Selected Emission Control Strategy?
    The State has not selected either emissions control strategy as the 
official, adopted emissions control strategy of the Phase II ozone 
attainment demonstration. The State, however, has adopted and developed 
regulations for many of the emission control measures contained in the 
two emission control strategies, and particularly for the controls 
contained in Strategy 2. Some of the emission control measures in 
Strategy 4, however, have not been adopted. For example, Indiana has 
not adopted major agricultural pesticide application restrictions and 
California low emission vehicle standards.
6. Transportation Conformity
Did the State Address Transportation Conformity in the Submittals?
    Indiana has not specifically addressed transportation conformity or 
associated mobile source emission budgets in the attainment 
demonstration and no such mobile source emission budget has been 
adopted as part of the Phase II submittal.
7. State Commitments
Are There any State Commitments for Further Analyses and Air Quality 
Plans Addressing a Final Ozone Attainment Demonstration for the 1-hour 
Ozone Standard?
    Indiana believes that, with the level of NOX emission 
reductions consistent with the NOX SIP call (Indiana itself 
is not committing at this time to develop a NOX SIP and 
implement NOX emission controls consistent with the 
NOX SIP call) and considering the VOC emission reductions 
from the 15 percent (1996) and 9 percent (post-1996) ROP plans, little 
or no additional VOC emission reductions are necessary to provide for 
attainment of the 1-hour ozone standard. Indiana has committed to 
submitting a final plan, including additional modeling and adopted 
emission control regulations, to achieve attainment of the 1-hour 
standard and to meet post-1999 ROP requirements, no later than the end 
of 2000. After the impact of the selected regional NOX 
controls is assessed, Indiana will reconsider the need for further VOC 
emission controls. If additional VOC control measures are needed, 
Indiana will revise the SIP to include the necessary regulations. 
Indiana commits to implement the emission control programs on a 
schedule necessary to meet ROP requirements.

[[Page 70528]]

B. Environmental Protection Agency Review of the Submittals

1. Adequacy of the State's Demonstration of Attainment
Did the State Adequately Document the Techniques and Data Used to 
Derive the Modeling Input Data and Modeling Results of the Analyses?
    The Phase I submittals from the States thoroughly documented the 
techniques and data used to derive the modeling input data. The April 
1998 submittal adequately summarized the modeling outputs and the 
conclusions drawn from these model outputs.
Did the Modeling Procedures and Input Data Used Comply With the Clean 
Air Act and EPA Requirements?
    Yes.
Did the States Adequately Demonstrate Attainment of the Ozone Standard?
    Indiana, in accordance with EPA's December 1997 guidance, has 
demonstrated that attainment of the standard is achievable provided 
sufficient reductions in background ozone concentrations (and 
background ozone precursor concentrations) occur as a result of the 
implementation of regional NOX emission controls under the 
NOX State implementation plan call. Indiana, however, has 
not selected a specific emission control strategy that would achieve 
attainment of the 1-hour ozone standard. This will not be done until 
the LADCO States submit a final attainment demonstration in December 
2000. By then the States plan to complete an assessment of the ozone 
impacts of regional NOX controls and to adopt additional VOC 
and NOX emission control measures needed to attain the 1-
hour standard.
Does the Weight of Evidence Test Support the States' Conclusions 
Regarding the Attainment Demonstration?
    The documented WOE analyses support the conclusions of the 
deterministic test and the statistical test. Both the deterministic 
test and the statistical test lead to similar conclusions regarding the 
ozone 1-hour standard attainment demonstration. Both the deterministic 
and the statistical tests, as supplemented by a WOE analysis, show that 
attainment can be achieved with local emission controls already 
implemented couple with significant reductions in transported ozone and 
ozone precursors.
2. Adequacy of the Emissions Control Strategy
Has an Adopted Emissions Control Strategy Been Adequately Documented?
    No. The State has not adopted a final emissions control strategy 
for attainment of the 1-hour ozone standard. The State, however, has 
demonstrated that significant reductions in transported ozone and 
NOX will be necessary to attain the 1-hour standard. These 
reductions are expected to occur as a result of the implementation of 
regional NOX emission reductions. All three of the LADCO 
States, including Indiana, are expected to implement alternative 
regional NOX controls within their States.
Is the Emission Control Strategy Acceptable?
    No. The State must select an emissions control strategy that is 
consistent with attainment in order to establish a motor vehicle 
emissions budget. The State must do so in sufficient time for EPA to 
find the motor vehicle emissions budget adequate by May 31, 2000. The 
State has committed to adopt and submit a final emissions control 
strategy associated with a revised modeling analysis by December 2000.
3. State Commitments
Are the State Commitments for Future Analyses and Finalization of the 
Attainment Demonstration Acceptable?
    Yes. Indiana's commitments to complete the attainment demonstration 
and to adopt and submit the post-1999 ROP plan (the post-1996 ROP plan, 
covering the period of 1997 through 1999, is currently under review by 
the EPA) by December 2000 are adequate.
4. Relationship to Other Requirements
Will the Future Analyses Adequately Address the Impacts of the EPA 
NOX State Implementation Plan Call?
    Yes. The LADCO States have made it very clear that the 1-hour ozone 
standard will be difficult to attain without the regional 
NOX emission reductions and that the final demonstration of 
attainment will incorporate the States' best estimates of the impacts 
of the NOX SIP call or of alternative regional 
NOX emission controls.
Has the State Specified and Adopted an Acceptable Transportation 
Conformity Mobile Source Emission Budget?
    No. The State has not selected a specific emission control 
strategy. The State must select a control strategy that is consistent 
with attainment of the NAAQS. The will need to establish a motor 
vehicle emissions budget based on the selected strategy and will need 
to submit the budget in time for EPA to find the budget adequate by May 
31, 2000.

C. Summary

Overall, Is Indiana's Ozone Attainment Demonstration Acceptable?
    Indiana's commitment to complete the control strategy adoption 
process is adequate to warrant a conditional approval of the attainment 
demonstration plan. Indiana has accomplished as much as can be expected 
at this time and has generally met the requirements of the EPA December 
1997 ozone attainment demonstration guidance, with the exception of 
adopting a final emission control strategy and associated emission 
control regulations.
What Portions of the Attainment Demonstration Need Additional Work and 
Consideration in the Final Attainment Demonstration?
    The following items need further consideration in the final ozone 
attainment demonstration:
    1. A final modeled demonstration of attainment that considers the 
impacts of the regional NOX emission reductions, local 
control measures, and NOX emissions control waiver (if 
maintained);
    2. Adoption and submission of CAA measures, including VOC and 
NOX (within the modeling domain) measures relied on in the 
final modeled attainment demonstration;
    3. Motor vehicle emissions budget, including both VOC and 
NOX emissions.
    The EPA has found that the motor vehicle emissions budget in the 
attainment demonstration submitted for the Chicago-Gary-Lake County 
ozone nonattainment area is inadequate for conformity purposes. The EPA 
is proposing to conditionally approve the attainment demonstration SIP 
if the State corrects the deficiencies that cause the motor vehicle 
emissions budget to be inadequate and, alternatively, to disapprove it 
if Indiana does not correct the deficiencies.

III. Proposed Action

    The Environmental Protection Agency proposes to issue a conditional 
approval of the ozone attainment demonstration. The State already 
committed to do the following in the April 1998 ozone attainment 
demonstration: (1) perform and submit a final modeled ozone

[[Page 70529]]

attainment demonstration by December 2000; (2) adopt and submit a 
specific emissions control strategy, including adopted control 
measures, adequate to attain the 1-hour ozone NAAQS in the ozone 
nonattainment area and throughout the ozone modeling domain by December 
2000; (3) adopt and submit control measures necessary to meet ROP from 
1999 until the attainment year and the associated target calculations. 
For EPA to issue a final conditional approval the State will need to 
take the following steps in sufficient time for EPA to determine by May 
31, 2000 that the state has an adequate motor vehicle emissions budget 
and an adequate commitment for a mid-course review: (1) Select a 
control strategy consistent with its current modeling analysis; (2) 
adopt and submit an adequate motor vehicle emissions budget consistent 
with the selected strategy; and (3) commit to perform a mid-course 
review in 2003.
    Because many States may shortly be submitting revised 
demonstrations with revised motor vehicle emission budgets, EPA is 
providing a 60 day comment period on this proposed rule. If Indiana 
submits a revised attainment demonstration during the 60 day comment 
period, EPA will place the revisions in the docket for this rulemaking 
and will post a notice on EPA's website at www.epa.gov/oms/traq. By 
posting notice on the website, EPA will also initiate the adequacy 
process.
    If the State does not take one or more of the actions listed above 
in time for EPA to make the May 31, 2000 determinations, EPA will 
disapprove Indiana's attainment demonstration submission for the 
Chicago-Gary-Lake County nonattainment area.
    If EPA issues a final conditional approval of the State's 
submission, the conditional approval will convert to a disapproval if 
the State does not adopt and submit a complete SIP submission with the 
following elements by December 31, 2000: (1) A final revised modeling 
analysis that fully assesses the impacts of regional NOX 
reductions, models a specific local emissions reduction strategy, and 
reconsiders the effectiveness of the NOX waiver; (2) control 
measures necessary to meet the ROP requirement from 1999 until the 
attainment year, including target calculations; and (3) VOC and 
regional (within the modeling domain) NOX emission control 
measures sufficient to support the final ozone attainment 
demonstration.
    If the State makes a complete submission with all of the above 
elements by December 31, 2000, EPA will propose action on the new 
submissions for the purpose of determining whether to issue a final 
full approval of the attainment demonstration.

What Are the Consequences of State Failure?

    This section explains the CAA consequences of State failure to meet 
the time frames and terms described generally in this notice. The CAA 
provides for the imposition of sanctions and the promulgation of a 
federal implementation plan if States fail to submit a required plan, 
submit a plan that is determined to be incomplete or if EPA disapproves 
a plan submitted by the State (We are using the phrase ``failure to 
submit'' to cover both the situation where a State makes no submission 
and the situation where the State makes a submission that we find is 
incomplete in accordance with section 110(k)(1)(B) and 40 CFR part 51, 
appendix V.) For purposes of sanctions, there are no sanctions clocks 
in place based on a failure to submit. Thus, the description of the 
timing of sanctions, below, is linked to a potential disapproval of the 
State's submission.

What Are the CAA's Provisions for Sanctions?

    If EPA disapproves a required SIP, such as the attainment 
demonstration SIPs, section 179(a) provides for the imposition of two 
sanctions. The first sanction would apply 18 months after EPA 
disapproves the SIP if the State fails to make the required submittal 
which EPA proposes to fully or conditionally approve within that time. 
Under EPA's sanctions regulations, 40 CFR 52.31, the first sanction 
would be 2:1 offsets for sources subject to the new source review 
requirements under section 173 of the CAA. If the State has still 
failed to submit a SIP for which EPA proposes full or conditional 
approval 6 months after the first sanction is imposed, the second 
sanction will apply. The second sanction is a limitation on the receipt 
of Federal highway funds. EPA also has authority under section 110(m) 
to a broader area, but is not proposing to take such action today.

What Are the CAA's FIP Provisions if a State Fails to Submit a Plan?

    In addition to sanctions, if EPA finds that a State failed to 
submit the required SIP revision or disapproves the required SIP 
revision EPA must promulgate a FIP no later than 2 years from the date 
of the finding if the deficiency has not been corrected. The attainment 
demonstration SIPs on which EPA is taking action today were originally 
due in November 1994. However, through a series of policy memoranda, 
EPA recognized that States had not submitted attainment demonstrations 
and were constrained to do so until ozone transport had been further 
analyzed. As provided in the Background, above, EPA provided for States 
to submit the attainment demonstration SIPs in two phases. In June 
1996, EPA made findings that ten States and the District of Columbia 
had failed to submit the phase I SIPs for nine nonattainment areas. 61 
FR 36292 (July 10, 1996). In addition on May 19, 1997, EPA made a 
similar finding for Pennsylvania for the Philadelphia area. 62 FR 
27201.
    In July 1998, several environmental groups filed a notice of 
citizen suit, alleging that EPA had outstanding sanctions and FIP 
obligations for the serious and severe nonattainment areas on which EPA 
is proposing action today. These groups filed a lawsuit in the Federal 
District Court for the District of Columbia on November 8, 1999.

IV. Administrative Requirements

A. Executive Orders 12866

    The Office of Management and Budget (OMB) has exempted this 
regulatory action from review under Executive Orders 12866, entitled 
``Regulatory Planning and Review.''

B. Executive Order 13045

    Executive Order 13045, entitled ``Protection of Children from 
Environmental Health Risks and Safety Risks'' (62 FR 19885, April 23, 
1997), applies to any rule that the EPA determines (1) is 
``economically significant,'' as defined under Executive Order 12866, 
and (2) the environmental health or safety risk addressed by the rule 
has a disproportionate effect on children. If the regulatory action 
meets both criteria, the Agency must evaluate the environmental health 
or safety effects of the planned rule on children and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    This final rule is not subject to Executive Orders 13045 because it 
does not involve decisions intended to mitigate environmental health 
and safety risks.

C. Executive Order 13084

    Under Executive Orders 13084, EPA may not issue a regulation that 
is not required by statute, that significantly affects or uniquely 
affects the communities of Indian tribal

[[Page 70530]]

governments, and that imposes substantial direct compliance costs on 
those communities, unless the Federal government provides the funds 
necessary to pay the direct compliance costs incurred by the tribal 
governments. If the mandate is unfunded, EPA must provide to the Office 
of Management and Budget, in a separately identified section of the 
preamble to the rule, a description of the extent of EPA's prior 
consultation with representatives of affected tribal governments, a 
summary of the nature of their concerns, and a statement supporting the 
need to issue the regulation. In addition, Executive Order 13084 
requires EPA to develop an effective process permitting elected and 
other representatives of Indian tribal governments ``to provide 
meaningful and timely input in the development of regulatory policies 
on matters that significantly or uniquely affect their communities.'' 
Today's rule does not significantly or uniquely affect the communities 
of Indian tribal governments. This action does not involve or impose 
any requirements that affect Indian Tribes. Accordingly, the 
requirements of section 3(b) of Executive Orders 13084 do not apply to 
this rule.

D. Executive Order 13132

    Executive Order 13132, Federalism (64 FR 43255, August 10, 1999), 
revokes and replaces Executive Orders 12612 (Federalism) and 12875 
(Enhancing the Intergovernmental Partnership). Executive Order 13132 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by State and local officials in the development of 
regulatory policies that have federalism implications.'' ``Policies 
that have federalism implications'' is defined in the Executive Order 
to include regulations that have ``substantial direct effects on the 
States, on the relationship between the national government and the 
States, or on the distribution of power and responsibilities among the 
various levels of government.'' Under Executive Order 13132, EPA may 
not issue a regulation that has federalism implications, that imposes 
substantial direct compliance costs, and that is not required by 
statute, unless the Federal government provides the funds necessary to 
pay the direct compliance costs incurred by State and local 
governments, or EPA consults with State and local officials early in 
the process of developing the proposed regulation. EPA also may not 
issue a regulation that has federalism implications and that preempts 
State law unless the Agency consults with State and local officials 
early in the process of developing the proposed regulation.
    This rule will not have substantial direct effects on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government, as specified in Executive Order 13132 (64 FR 
43255, August 10, 1999), because it merely approves a State rule 
implementing a federal standard, and does not alter the relationship or 
the distribution of power and responsibilities established in the Clean 
Air Act. Thus, the requirements of section 6 of the Executive Order do 
not apply to this rule.

E. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to conduct a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements unless the agency certifies 
that the rule will not have a significant economic impact on a 
substantial number of small entities. Small entities include small 
businesses, small not-for-profit enterprises, and small governmental 
jurisdictions. This proposed rule will not have a significant impact on 
a substantial number of small entities because SIP approvals under 
section 110 and subchapter I, part D of the Clean Air Act do not create 
any new requirements but simply approve requirements that the State is 
already imposing. Therefore, because the Federal SIP approval does not 
create any new requirements, I certify that this action will not have a 
significant economic impact on a substantial number of small entities. 
Moreover, due to the nature of the Federal-State relationship under the 
Clean Air Act, preparation of a flexibility analysis would constitute 
Federal inquiry into the economic reasonableness of state action. The 
Clean Air Act forbids EPA to base its actions concerning SIPs on such 
grounds. Union Electric Co. v. U.S. EPA, 427 U.S. 246, 255-66 (1976); 
42 U.S.C. 7410(a)(2).
    If the conditional approval is converted to a disapproval under 
section 110(k), based on the State's failure to meet the commitment, it 
will not affect any existing State requirements applicable to small 
entities. Federal disapproval of the State submittal does not affect 
State-enforceability. Moreover, EPA's disapproval of the submittal does 
not impose any new requirements. Therefore, I certify that such a 
disapproval action will not have a significant economic impact on a 
substantial number of small entities because it would not remove 
existing requirements nor would it substitute a new Federal 
requirement.
    The EPA's alternative proposed disapproval of the State request 
under section 110 and subchapter I, part D of the Act would not affect 
any existing requirements applicable to small entities. Any pre-
existing Federal requirements would remain in place after this 
disapproval. Federal disapproval of the State submittal does not affect 
State-enforceability. Moreover EPA's disapproval of the submittal would 
not impose any new Federal requirements. Therefore, I certify that the 
proposed disapproval would not have a significant impact on a 
substantial number of small entities.

F. Unfunded Mandates

    Under section 202 of the Unfunded Mandates Reform Act of 1995 
(``Unfunded Mandates Act''), signed into law on March 22, 1995, EPA 
must prepare a budgetary impact statement to accompany any proposed or 
final rule that includes a Federal mandate that may result in estimated 
annual costs to State, local, or tribal governments in the aggregate; 
or to private sector, of $100 million or more. Under section 205, EPA 
must select the most cost-effective and least burdensome alternative 
that achieves the objectives of the rule and is consistent with 
statutory requirements. Section 203 requires EPA to establish a plan 
for informing and advising any small governments that may be 
significantly or uniquely impacted by the rule.
    EPA has determined that the proposed conditional approval action 
does not include a Federal mandate that may result in estimated annual 
costs of $100 million or more to either State, local, or tribal 
governments in the aggregate, or to the private sector. This Federal 
action approves pre-existing requirements under State or local law, and 
imposes no new requirements. Accordingly, no additional costs to State, 
local, or tribal governments, or to the private sector, result from 
this action.
    Sections 202 and 205 do not apply to the proposed disapproval 
because the proposed disapproval of the SIP submittal would not, in and 
of itself, constitute a Federal mandate because it would not impose an 
enforceable duty on any entity. In addition, the Act does not permit 
EPA to consider the types of analyses described in section 202 in 
determining whether a SIP submittal meets the CAA. Finally, section 203 
does not apply to the proposed

[[Page 70531]]

disapproval because it would affect only the State of Indiana, which is 
not a small government.

G. National Technology Transfer and Advancement Act

    Section 12 of the National Technology Transfer and Advancement Act 
(NTTAA) of 1995 requires Federal agencies to evaluate existing 
technical standards when developing new regulations. To comply with 
NTTAA, the EPA must consider and use ``voluntary consensus standards'' 
(VCS) if available and applicable when developing programs and policies 
unless doing so would be inconsistent with applicable law or otherwise 
impractical.
    EPA believes that VCS are inapplicable to this action. Today's 
action does not require the public to perform activities conducive to 
the use of VCS.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Hydrocarbons, 
Nitrogen dioxide, Ozone.

    Authority: 42 U.S.C. 7401 et seq.
    Dated: November 30, 1999.
Francis X. Lyons,
Regional Administrator, Region 5.
[FR Doc. 99-31721 Filed 12-15-99; 8:45 am]
BILLING CODE 6560-50-P