Technology Transfer Network / NAAQS
Ozone Implementation

Approval and Promulgation of Air Quality
Implementation Plans; Maryland;
One-Hour Ozone Attainment Demonstration
for the Baltimore Ozone Nonattainment Area

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

Federal Register Document

[Federal Register: December 16, 1999 (Volume 64, Number 241)]

[Proposed Rules]

[Page 70397-70412]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr16de99-27]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[MD 074-3046; FRL-6502-4]

Approval and Promulgation of Air Quality Implementation Plans;

Maryland; One-Hour Ozone Attainment Demonstration for the Baltimore

Ozone Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing to approve the State Implementation Plan

(SIP) consisting of the 1-hour ozone attainment demonstration for the

Baltimore severe nonattainment area submitted by the Maryland

Department of the Environment (MDE) on April 29, 1998 and August 18,

1998. We are also proposing, in the alternative, to disapprove this

demonstration if Maryland does not submit an adequate motor vehicle

emissions budget consistent with attainment and adopt and submit rules

for the regional NO_X reductions consistent with the modeling

demonstration. For purposes of an adequate motor vehicle emissions

budget, the State will need to reaffirm that its previously submitted

enforceable commitment to adopt the measures needed for attainment

would apply to the additional measures to reduce emissions to support

the attainment test. The reaffirmation must also include the State's

commitment to the performance of a mid-course review and to revisions

to the SIP and motor vehicle emissions budget after MOBILE6 (the most

recent model for estimating mobile source emissions) is released.

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

2000.

ADDRESSES: Written comments may be mailed to David L. Arnold, Chief,

Ozone & Mobile Sources Branch, Mailcode 3AP21, U.S. Environmental

Protection Agency, Region III, 1650 Arch Street, Philadelphia,

Pennsylvania 19103. Copies of the documents relevant to this action are

available for public inspection during normal business hours at the Air

Protection Division, U.S. Environmental Protection Agency, Region III,

1650 Arch Street, Philadelphia, Pennsylvania 19103; and the Maryland

Department of the Environment, 2500 Broening Highway, Baltimore,

Maryland, 21224.

FOR FURTHER INFORMATION CONTACT: Cristina Fernandez, (215) 814-2178. Or

by e-mail at fernandez.cristina@epa.gov.

SUPPLEMENTARY INFORMATION: This document provides background

information on attainment demonstration SIPs for the 1-hour ozone

national ambient air quality standard (NAAQS) and an analysis of the 1-

hour ozone attainment demonstration SIP submitted by MDE for the

Baltimore area. This document addresses the following questions:

What is the Basis for the Attainment Demonstration SIP?

What are the Components of a Modeled Attainment Demonstration?

What is the Frame Work for Proposing Action on the Attainment

Demonstration SIPs?

What Does EPA Expect to Happen with Respect to Attainment

Demonstrations for the Severe 1-Hour Ozone Nonattainment Areas?

What are the Relevant Policy and Guidance Documents?

How Does Maryland's Submittal Satisfy the Frame Work?

[[Page 70398]]

I. Background

A. What is the Basis for the Attainment Demonstration SIP?

1. CAA Requirements

The Clean Air Act (CAA) requires EPA to establish national ambient

air quality standards (NAAQS or standards) for certain widespread

pollutants that cause or contribute to air pollution that is reasonably

anticipated to endanger public health or welfare. CAA 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 nitrogen

oxides (NO_X) and volatile organic compounds (VOCs) react in

the presence of sunlight to form ground-level ozone. NO_X 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. An area is violating the standard if, over a consecutive

three-year period, more than three exceedances are expected to occur at

any one monitor. The CAA, 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 three-year

period from 1987-1989. CAA section 107(d)(4); 56 FR 56694 (Nov. 6,

1991). The CAA further classified these areas, based on the area's

design value, as marginal, moderate, serious, severe or extreme. CAA

section 181(a). Marginal areas were suffering the least significant air

pollution problems while the areas classified as severe and extreme had

the most significant air pollution problems.

The control requirements and dates by which attainment needs to be

achieved vary with the 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. The Baltimore nonattainment

area is classified as severe and its attainment date is November 15,

2005.

Under section 182(c)(2) and (d) of the CAA, 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

reductions in VOC emissions of 9 percent for each three-year period

until the attainment year (rate-of-progress or ROP). In some cases,

NO_X emission reductions can be substituted for the required

VOC emission reductions. Today, in this proposed rule, EPA is proposing

action on the attainment demonstration SIP submitted by Jane T.

Nishida, Secretary of the Maryland Department of the Environment for

the Baltimore area. EPA will take action on the Maryland's ROP plan in

a separate rulemaking action. In addition, elsewhere in this Federal

or severe 1-hour ozone attainment demonstration and, in some cases, ROP

SIPs. The additional nine areas are Greater Connecticut (CT),

Springfield (Western Massachusetts) (MA), New York-North New Jersey-

Long Island (NY-NJ-CT), 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), 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 control measures necessary to achieve those

reductions. 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), 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.

2. History and Time Frame for the State's Attainment Demonstration SIP

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 NO_X and

VOCs 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.

\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 NO_X 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 CAA 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 target calculations for post-1999 ROP

and the control measures necessary for attainment and ROP plans through

the attainment year by the end of 2000 ³;

[[Page 70399]]

(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 2 submission. Motor

vehicle emissions 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 CAA,

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 the State has relied

on a commitment to submit these measures by December 2000, EPA is

proposing an approval of the area's attainment demonstration. Some

severe areas submitted the actual adopted control measures and are

not relying on a commitment.

\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 https://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 NO_X 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 NO_X emissions

reductions within the State to a level consistent with a NO_X

emissions budget identified in the final rule. 63 FR 57356 (Oct. 27,

1998). This final rule is commonly referred to as the NO_X

SIP Call.

3. Time Frame for Taking Action on Attainment Demonstration SIPs for 10

Serious and Severe Areas

The States generally submitted the SIPs between April and October

of 1998; some States are still submitting additional revisions as

described below. Under the CAA, 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 10 serious and severe 1-hour ozone attainment demonstration SIPs

(located in 13 States and the District of Columbia) and intends to take

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.

4. Options for Action on a State's Attainment Demonstration SIP

Depending upon the circumstances unique to each of the 10 area 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 identify additional

action that will be necessary from the State.

The CAA provides for EPA to approve, disapprove, partially approve

or conditionally approve a State's plan submission. CAA 110(k). The EPA

must fully approve the submission if it meets the attainment

demonstration requirement of the CAA. 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

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 CAA. 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 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. 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. What Are the 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 https://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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1. Modeling Requirements

For purposes of demonstrating attainment, the CAA 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 and to predict

air quality changes

[[Page 70400]]

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 bad

air quality, 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 domain

size. The domain should be larger than the designated nonattainment

area to reduce uncertainty in the boundary conditions and should

include 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 that describe atmospheric conditions and emissions

inputs. Finally, the State needs to verify that the model is properly

simulating the chemistry and atmospheric conditions through diagnostic

analyses and model performance tests. 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 concentration above 0.124 ppm ozone

indicates that the area is expected to exceed the standard in the

attainment year and a prediction at or below 0.124 ppm indicates that

the area is expected to attain the standard. 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 three-year

period, the area has an average of one or fewer exceedances per year,

the area is not violating the standard. Thus, if the State models a

very extreme day, 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

three readings above the standard over a three-year period before an

area is considered to be in violation.)

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 three-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 the 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 three-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.

2. Additional Analyses Where 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 exclusive 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

[[Page 70401]]

projections, EPA believes a viable attainment demonstration that relies

on WOE 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 in Section C.6.

C. What is the Frame Work for Proposing Action on 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 or conditionally approve

the 1-hour attainment demonstration SIPs. These elements are listed

below and then described in detail.

CAA measures and measures relied on in the modeled attainment

demonstration SIP. This includes adopted and submitted rules for all

previously required CAA 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.

NO_X reductions affecting boundary conditions.

Motor vehicle emissions budget. A motor vehicle emissions budget

which can be determined by EPA to be adequate for conformity purposes.

Tier 2/Sulfur program benefits where needed to demonstrate

attainment. Inclusion of reductions expected from EPA's Tier 2 tailpipe

and low sulfur-in-fuel standards in the attainment demonstration and

the motor vehicle emissions budget.

In certain areas, additional measures to further reduce emissions

to support the attainment test. Additional measures, may be measures

adopted regionally such as in the Ozone Transport Region (OTR), or

locally (intrastate) in individual States.

Mid-course review. An enforceable commitment to conduct a mid-

course review and evaluation based on air quality and emission trends.

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.

1. CAA Measures and Measures Relied on in the Modeled Attainment

Demonstration SIP

The States should have adopted the control measures already

required under the CAA 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 CAA 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

CAA. (For serious areas, these should have already been identified and

adopted, whereas severe areas have until December 2000 to submit

measures necessary 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 two tables present a summary of the CAA requirements

that need to be met for each serious and severe nonattainment area for

the 1-hour ozone NAAQS. These requirements are specified in section 182

of the CAA. Information on more measures that States may have adopted

or relied on in their current SIP submissions is not shown in the

tables. EPA will need to take final action approving all measures

relied on for attainment, including the required ROP control measures

and target calculations, before EPA can issue a final full approval of

the attainment demonstration as meeting CAA section 182(c)(2) (for

serious) or (d) (for severe).

Table 1--CAA Requirements for Serious Areas

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--NSR for VOC and NO_X ¹, including an offset ratio of 1.2:1 and a major

VOC and NO_X source cutoff of 50 tons per year (tpy).

--Reasonable Available Control Technology (RACT) for VOC and NO_X ¹.

--Enhanced Inspection and Maintenance (I/M) program.

--15% volatile organic compound (VOC) plans.

--Emissions inventory.

--Emission statements.

--Attainment demonstration.

--9 percent ROP plan through 1999.

--Clean fuels program or substitute.

--Enhanced monitoring Photochemical Assessment Monitoring Stations

(PAMS).

--Stage II vapor recovery.

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\1\Unless the area has in effect a NO_X waiver under section 182(f).

Baltimore area is not such an area.

Table 2--CAA Requirements for Severe Areas

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--All of the nonattainment area requirements for serious areas.

--NSR, including an offset ratio of 1.3:1 and a major VOC and NO_X source

cutoff of 25 tons per year (tpy).

--Reformulated gasoline.

--9 percent ROP plan through attainment year.

--Requirement for fees for major sources for failure to attain (SIP due

12/31/00).

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2. NO_X Reductions Affecting Boundary Conditions

The EPA completed final rulemaking on the NO_X SIP call

on October 27, 1998, which required States to address transport of

NO_X and ozone to other States. To address transport, the

NO_X SIP call established emissions budgets for

NO_X that 23 jurisdictions were required to show they would

meet through enforceable SIP measures adopted and submitted by

September 30, 1999. The NO_X 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 portion of the NNO_X SIP

call rule requiring States to submit rules by September 30, 1999.

The NO_X 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,

D.C. (DC-MD-VA), Atlanta GA, Milwaukee-Racine WI, and Chicago-Gary-Lake

County (IL-IN).

Emission reductions that will be achieved through EPA's

NO_X 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 NO_X SIP Call reductions for

purposes of determining the boundary conditions of the modeling domain.

Emission reductions assumed in the attainment demonstrations are

modeled

[[Page 70402]]

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 NO_X SIP Call rule remains in

effect. Therefore, EPA believes it is appropriate to allow States to

continue to assume the reductions from the NO_X SIP call in

areas outside the local 1-hour modeling domains. If States assume

control levels and emission reductions other than those of the

NO_X SIP call within their State but outside of the modeling

domain, 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 NO_X SIP call budgets prior to the time that all

States are required to comply with the NO_X SIP call. If the

reductions from the NNO_X 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 the State

inside the local modeling domain ⁷ for purposes of the

modeled attainment demonstration must be adopted and submitted as part

of the State's 1-hour attainment demonstration SIP. It is only for

reductions occurring outside the local modeling domain that States may

assume implementation of NO_X SIP call measures and the

resulting boundary conditions.

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\7\ For the purposes of this document, ``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.

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3. Motor Vehicle Emissions Budget

The EPA believes that attainment demonstration SIPs must

necessarily estimate the motor vehicle emissions that will be produced

in the attainment year and 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 CAA 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

appropriately identified motor vehicle emissions budgets are a

necessary part of an attainment demonstration SIP. A SIP cannot

effectively demonstrate 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

all areas in today's proposals are inadequate or missing from the

attainment demonstration. Therefore, EPA is proposing to disapprove the

attainment demonstration SIPs for those nine 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 a 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 the area's attainment demonstration. The emissions

budget should reflect all 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.

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\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

hearing process is not yet complete, then the draft budget for

public hearing 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.

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4. Tier 2/Sulfur Program Benefits

On May 13, 1999, EPA published a Notice of Proposed Rulemaking

(NPRM) proposing a major, comprehensive program designed to

significantly reduce emissions from passenger cars and light trucks

(including sport-utility vehicles, minivans, and pickup trucks) and to

reduce sulfur in gasoline. Under the proposed program, automakers would

produce vehicles designed to have very low emissions when operated on

low-sulfur gasoline, and oil refiners would provide that cleaner

gasoline nationwide. The EPA subsequently issued two supplemental

notices. 64 FR 35112 (June 30, 1999); 64 FR 57827 (October 27, 1999).

These two supplemental notices provide 1-hour ozone modeling and

monitoring information that support EPA's belief that the Tier 2/Sulfur

program is necessary to help areas attain the 1-hour NAAQS. Under the

proposed rule, NOx and VOC emission reductions (as well as other

reductions not directly relevant for attainment of the 1-hour ozone

standard) would occur beginning in the 2004 ozone season although

incentives for early compliance by vehicle manufacturers and refiners

will likely result in some reductions prior to 2004. Nationwide, the

Tier 2/Sulfur program is projected to result in reductions of

approximately 800,000 tons of NOx per year by 2007 and 1,200,000 tons

by 2010.

In the October 27, 1999 supplemental notice, EPA reported in Table

1 that EPA's regional ozone modeling indicated that 17 metropolitan

areas for which the 1-hour standard applies need the Tier 2/Sulfur

program reductions to help attain the 1-hour ozone standard. The

Baltimore area whose attainment demonstration EPA is proposing to

approve today is included on that list.

The EPA issued a memorandum that provides estimates of the

emissions reductions associated with the Tier

2/Sulfur program proposal.¹⁰ The memorandum provides the

tonnage benefits for the Tier 2/Sulfur program in 2007 on a county-by-

county basis for all counties within the 10 serious and severe

nonattainment areas for which EPA is proposing to take action today and

the 2005 tonnage benefits for the Tier 2/Sulfur program for each county

for three areas.

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\10\ Memorandum, ``1-Hour Ozone Attainment Demonstrations and

Tier 2/Sulfur Rulemaking'' from Lydia Wegman, Office of Air Quality

Planning and Standards and Merrylin Zaw-Mon, Office of Mobile

Sources to the Air Division Directors, Regions I-VI, issued November

8, 1999. A copy of this memorandum may be found on EPA's web site at

https://www.epa.gov/oms/transp/traqconf.htm.

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The EPA also issued a memorandum which explains the connection

between the Tier 2/Sulfur program, motor vehicle emissions budgets for

conformity determinations, and timing for SIP revisions to account for

the Tier 2/Sulfur program benefit.¹¹ This memorandum

explains that conformity analyses in serious and severe ozone

nonattainment areas can begin including Tier 2/Sulfur program

[[Page 70403]]

benefits once EPA's Tier 2 rule is promulgated, provided that the

attainment demonstration SIPs and associated motor vehicle emissions

budgets include the Tier 2 benefits. For areas that require all or some

portion of the Tier 2 benefits to demonstrate attainment but have not

yet included the benefits in the motor vehicle emissions budgets, EPA's

adequacy finding will include a condition that conformity

determinations may not take credit for Tier 2 until the SIP budgets are

revised to reflect Tier 2 benefits. See EPA's memorandum for more

information.

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\11\ Memorandum, ``Guidance on Motor Vehicle Emissions Budgets

in One-Hour Ozone Attainment Demonstrations'', from Merrylin Zaw-

Mon, Office of Mobile Sources, to Air Division Directors, Regions I-

VI, issued November 3, 1999. A copy of this memorandum may be found

on EPA's web site at https://www.epa.gov/oms/transp/traqconf.htm.

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For the New York-North New Jersey-Long Island, Philadelphia-

Wilmington-Trenton, Baltimore, Atlanta, and Houston nonattainment

areas, the EPA is proposing to determine that additional emission

reductions beyond those provided by the SIP submission are necessary

for attainment. With the exception of the Atlanta nonattainment area, a

portion of that reduction will be achieved by EPA's Tier 2/Sulfur

program, which EPA expects to finalize shortly. States that need to

rely in whole or in part on the Tier 2 benefits to help demonstrate

attainment will need to adjust the demonstration for their SIP

submission, emission inventories and motor vehicle emissions budgets to

include the Tier 2/Sulfur program reductions in order for EPA to

approve the SIP submittal. The submittal requirement including the

analysis to make that submission is described in the two memoranda

cited. States may use the tonnage benefits and guidance in these

memoranda to make these adjustments to the SIP submission and motor

vehicle emission budgets. The EPA encourages States to submit these SIP

revisions by December 31, 1999 to allow EPA to include them in the

motor vehicle emissions budget adequacy determinations which need to be

completed by May 31, 2000. Alternatively, these revisions should be

submitted by July 2000 for serious nonattainment areas, as EPA

anticipates completing rulemaking on these SIPs in the fall of 2000.

For severe nonattainment areas, these revisions should be submitted by

December 31, 2000.

A number of areas for which the EPA is not proposing to determine

that additional emission reduction beyond those provided by the SIP

submission are necessary for attainment will be taking a partial credit

for Tier 2 when they use credit from national low emissions vehicles

(NLEV) in their attainment demonstration. These nonattainment areas are

the Milwaukee-Racine, Chicago-Gary-Lake County and Metropolitan

Washington, D.C. areas. By regulation, the NLEV standards do not extend

beyond the 2003 model year unless EPA promulgates Tier 2 vehicle

standards at least as stringent as the NLEV standards. See 40 CFR

86.1701-99(c). Thus, the emission reductions relied upon from 2004 and

later model year NLEV vehicles will actually be due to the promulgation

of the Tier 2 standards, either through the extension of the NLEV

program or a portion of the reduction from vehicles meeting the Tier 2

standards.

Like all the other SIPs that rely on Tier 2 reductions in order to

demonstrate attainment, the attainment demonstrations for the

Milwaukee-Racine, Chicago-Gary-Lake County and Metropolitan Washington,

D.C. areas must be revised to estimate the effects of Tier 2 according

to our policy before EPA can take final action approving such

attainment demonstrations. Until the SIPs are revised to include full

Tier 2 credit, EPA can determine by May 31, 2000 that a motor vehicle

emissions budget is adequate if the budget would be otherwise adequate.

No conditions need be placed on such adequacy determinations since the

budgets in such SIPs already include reductions equivalent to the

amount of emission reductions the areas will be relying on from Tier 2

by virtue of the NLEV reductions included in the budgets.

Revisions to the motor vehicle emissions budget and the attainment

demonstration when EPA issues the MOBILE6 model. Within one year of

when EPA issues the MOBILE6 model for estimating mobile source

emissions which takes into account the emissions benefit of EPA's Tier

2/Sulfur program, States will need to revise their motor vehicle

emissions budgets in their attainment demonstration SIPs if the Tier 2/

Sulfur program is necessary for attainment. In addition, the budgets

will need to be revised using MOBILE6 in those areas that do not need

the Tier 2/Sulfur program for attainment but decide to include its

benefits in the motor vehicle emissions budget anyway. The EPA will

work with States on a case-by-case basis if the new emission estimates

raise issues about the sufficiency of the attainment demonstration.

States described in the paragraph above will need to submit a

commitment in the near term to revise their motor vehicle emissions

budget within one year after EPA's release of MOBILE6. This commitment

should be submitted to EPA along with the other commitments discussed

elsewhere in this document, or alternatively, as part of the SIP

revision that modifies the motor vehicle emission inventories and

budgets to include the Tier 2/Sulfur program benefits needed in order

for EPA to approve the SIP submittal.¹²

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\12\ For purposes of conformity, the State needs a commitment

that has been subject to 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 revision of the budget after

the release of MOBILE6.

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5. Additional Measures to Further Reduce Emissions

The EPA is proposing to find that the attainment demonstrations for

New York-North New Jersey-Long Island, Atlanta; Houston; Baltimore, and

Philadelphia-Wilmington-Trenton even considering the Tier 2/Sulfur

program reductions and the WOE, will not achieve attainment without the

application of additional emission control measures to achieve

additional emission reductions. Thus, for each of these areas, EPA has

identified specific percentages of NO_X and/or VOC emissions

which must be reduced through additional control measures in order to

demonstrate attainment and to enable EPA to approve the demonstration.

The need for additional emission reductions is generally based on a

lack of sufficient compelling evidence that the demonstration shows

attainment at the current level of adopted or planned emission

controls. This is discussed in detail below for the Baltimore area. The

method used by EPA to calculate the amount of additional reductions is

described in a technical support document located in the record for

this proposed rule. Briefly, the method makes use of the relationship

between ozone and its precursors (VOC and NO_X) to identify

additional reductions that, at a minimum, would bring the model

predicted future ozone concentration to a level at or below the

standard. The relationship is derived by comparing changes in either

(1) the model predicted ozone to changes in modeled emissions or (2) in

observed air quality to changes in actual emissions.

The EPA is not requesting that States perform new photochemical

grid modeling to assess the full air quality impact of the additional

measures that would be adopted. Rather, as described above, one of the

factors that EPA can consider as part of the WOE analysis of the

attainment demonstration is whether there will be additional emission

reductions anticipated that were not modeled. Therefore, EPA will

consider the reductions from these

[[Page 70404]]

additional measures as part of the WOE analysis if the State adopts the

measures or, as appropriate, submits an enforceable commitment to adopt

the measures.

As an initial matter, for areas that need additional measures, the

State must submit a commitment to adopt additional control measures to

meet the level of reductions that EPA has identified as necessary for

attainment. For purposes of conformity, if the State submitted a

commitment, which has been subject to public hearing, to adopt the

control measures necessary for attainment and ROP through the area's

attainment date in conformance with the December 1997 Wilson policy,

the State will not need an additional commitment at this time. However,

the state will need to amend its commitment by letter to provide two

things concerning the additional measures.

First, the State will need to identify a list of potential control

measures (from which a set of measures could be selected) that, when

implemented, would be expected to provide sufficient additional

emission reductions to meet the level of reductions that EPA has

identified as necessary for attainment. States need not commit to adopt

any specific measures on their list at this time, but if they do not do

so, they must identify sufficient additional emission reductions to

attain the standard with the submitted motor vehicle emissions budget.

These measures may not involve additional limits on highway

construction beyond those that could be imposed under the submitted

motor vehicle emissions budget. (See memorandum, ``Guidance on Motor

Vehicle Emissions Budgets in One-Hour Ozone Attainment

Demonstrations,'' from Merrylin Zaw-Mon, Office of Mobile Sources, to

Air Division Directors, Regions I-VI. ¹³) States may, of

course, select control measures that do impose limits on highway

construction, but if they do so, they must revise the budget to reflect

the effects of specific, identified measures that were either committed

to in the SIP or were actually adopted. Otherwise, EPA could not

conclude that the submitted motor vehicle emissions budget would be

providing for attainment, and EPA could not find it adequate for

conformity purposes.

---------------------------------------------------------------------------

\13\ Memorandum, ``Guidance on Motor Vehicle Emissions Budgets

in One-Hour Ozone Attainment Demonstrations'', from Merrylin Zaw-

Mon, Office of Mobile Sources, to Air Division Directors, Regions I-

VI, issued November 3, 1999. A copy of this memorandum may be found

on EPA's web site at https://www.epa.gov/oms/transp/traqconf.htm.

---------------------------------------------------------------------------

Second, the letter should provide that the State will recalculate

and submit a revised motor vehicle emissions budget that includes the

effects, if any, of the measure or measures that are ultimately adopted

when those measures are submitted as SIP revisions should any of the

measures pertain to motor vehicles.

For purposes of approving the SIP, the State will need an

enforceable commitment that identifies the date by which the additional

measures will be submitted, identifies the percentage reductions needed

of VOC and NO_X, and provides that the State will recalculate

and submit a revised motor vehicle emissions budget that includes the

effects, if any, of the measure or measures that are ultimately adopted

when these measures are submitted as SIP revisions should any of the

measures pertain to motor vehicles. To the extent the State's current

commitment does not include one of the above items or to the extent

that a State plans to revise one of the above items in an existing

commitment, the State will need a new public hearing.

For areas within the OTR, EPA believes it is appropriate to provide

a State that is relying on a regional solution to a Congressionally-

recognized regional air pollution problem with more time to adopt and

submit measures for additional reductions to EPA than for a State that

will rely on intrastate measures to achieve the reductions. Therefore,

the EPA believes that States in the OTR must be allowed sufficient time

for the OTR to analyze the appropriate measures as well as time for the

State to adopt the measures. For these States, EPA believes it is

appropriate for them to commit to work through the OTR to develop a

regional strategy regarding the measures necessary to meet the

additional reductions identified by EPA for these areas. However, as a

backstop, the State will need to commit to adopt intrastate measures

sufficient to achieve the additional reductions if the regional

measures are not identified by the OTR and adopted by the relevant

States. For purposes of conformity, if the State submitted a commitment

consistent with the December 1997 Wilson policy and which has been

subject to public hearing, the State may amend its current commitment

by letter to provide these assurances. However, before EPA can take

final rulemaking action to approve the attainment demonstration, the

State will need to meet the public hearing requirements for the

commitment and submit it to EPA as a SIP revision. The EPA will have to

propose and take final action on this SIP revision before EPA can fully

approve the State's attainment demonstration. The State will have to

submit the necessary measures themselves (and a revised motor vehicle

emissions budget that includes the effects, if any, of the measure or

measures that are ultimately adopted should any of the measures pertain

to motor vehicles) as a SIP revision no later than October 31, 2001.

Guidance on additional control measures. Much progress has been

made over the past 25 years to reduce VOC emissions and over the past 9

years to reduce NO_X emissions. Many large sources have been

controlled to some extent through RACT rules or other emission

standards or limitations, such as maximum achievable control technology

(MACT), new source performance standards (NSPS) and the emission

control requirements for NSR--lowest achievable emissions rate (LAER)

and best achievable control technology (BACT). However, there may be

controls available for sources that have not yet been regulated as well

as additional means for achieving reductions from sources that have

already been regulated. The EPA has prepared a report to assist States

in identifying additional measures. This report is called ``Serious and

Severe Ozone Nonattainment Areas: Information on Emissions, Control

Measures Adopted or Planned and Other Available Control Measures.'' The

purpose of this report is to provide information to State and local

agencies to assist them in identifying additional control measures that

can be adopted into their SIPs to support the attainment demonstrations

for the serious and severe nonattainment areas under consideration.

This report has been added to the record for this proposal.

In summary, the report provides information in four areas. First,

the report contains detailed information on emissions for ozone

precursor emissions of NO_X and VOCs. This inventory data

gives an indication of where the major emissions are coming from in a

particular geographic area and may indicate where it will be profitable

to look for further reductions. Second, the report contains information

on control measures for emission sources of NNO_X and VOC

(including stationary, area and mobile source measures) for which

controls may not have been adopted by many jurisdictions. This would

include many measures listed among the control measures EPA considered

when developing the Regulatory Impact Analysis (RIA) for promulgation

of the 8-hour ozone NAAQS. Third, the report includes information on

standards EPA has issued for the NSPS and MACT programs as well as

information on

[[Page 70405]]

alternative control techniques (ACT) documents. This may be useful to

States who may already specify emission limits on existing source

categories to which NSPS and MACT for new sources apply, but the

current RACT level of control for these existing sources may not match

the level specified in the NSPS or MACT standards for new sources or

sources which emit hazardous air pollutants. Finally, the report

includes information on the control measures not already covered

elsewhere that States have adopted, or have proposed to adopt at the

date of the report, into their SIPs. Comparison of information on

measures already adopted into others' SIPs may help inform States about

reductions that may be available from their sources whose emissions are

currently not regulated.

Another source of information is the BACT and LAER determinations

that States have made for individual new sources. Information on BACT/

LAER determinations is available through EPA's RACT/BACT/LAER

Clearinghouse (RBLC) which may be accessed on EPA's web site on the

Internet at the following address: www.epa.gov/ttn/catc/.

The ACT documents for VOC and NO_X are valuable because

EPA has not issued control technique guidelines (CTGs) that specify the

level of RACT for several categories of sources. For some of these

source categories, EPA has prepared ACT documents which describe

various control technologies and associated costs for reducing

emissions. While States were required to adopt RACT for major sources

within these source categories, the ACT documents may identify an

additional level of control for regulated sources or may provide

control options for non-major sources within these source categories.

States are free to evaluate the various options given and use the

results to assist in formulating their own regulations.

The EPA report lists the various sources EPA used to develop the

lists of additional measures. These sources include an EPA draft

control measure data base, State and Territorial Air Pollution

Administrators and the Association of Local Air Pollution Control

Official's (STAPPA/ALAPCO's) books ``Controlling Nitrogen Oxides under

the Clean Air Act: A Menu of Options'', and ``Meeting the 15-Percent

Rate-of-Progress Requirement Under the Clean Air Act: A Menu of

Options'', California's ozone SIP for the South Coast and various ACT

documents.

There is one control approach which bears special mention because

it is broader in application than any one specific control measure.

That is the approach of ``cap and trade.'' In this approach, a cap is

placed on emissions, and existing sources are given emission

allotments. Under a declining cap, emissions would be decreased each

year. Sources may over-control and sell part of their allotments to

other sources which under-control. Overall, the percentage decrease in

emissions is maintained, but the reductions are made where they are

most economical. A cap and trade program has been in operation in the

South Coast Air Quality Management District in California since about

1992.

The State of Illinois has adopted a declining cap and trade

program. The Illinois program will set a cap on future emissions of

major sources in the Chicago area that in most cases is 12 percent

lower than baseline emissions. Illinois will issue a number of emission

allotments corresponding to the cap level and will require each source

to have VOC emissions at or below the level for which it holds emission

allotments. Trading of emission allotments will be allowed, so that

sources that reduce VOC emissions more than 12 percent may sell

emission allotments, and sources that reduce VOC emission less than 12

percent must buy emission allotments. The proposed reductions are

planned to begin in the next ozone season, May 2000.

In addition, EPA's draft economic incentives program guidance (EIP)

was proposed in September 1999. This encourages cost-effective and

innovative approaches to achieving air pollution goals through

emissions trading. Such an approach has been demonstrated to be

successful and cost-effective in reducing air pollution in EPA's acid

rain emissions trading program. These and other similar programs should

allow cost-effective implementation of additional control measures.

Finally, a reduction in VOC and NOx emissions can be achieved

through a wide range of control measures. These measures range from

technology based actions such as retrofitting diesel trucks and buses,

and controlling ground service equipment at airports to activity based

controls such as increased use of transit by utilizing existing Federal

tax incentives, market and pricing based programs, and ozone action

days. States can also achieve emission reductions by implementing

programs involving cleaner burning fuels. The State of Texas is also

considering a rule to change the times during the day in which

construction can occur to reduce ozone precursor emissions during

periods when ozone formation is occurring. There are a wide range of

new and innovative programs beyond the few examples listed here. These

measures, if taken together, can provide significant emission

reductions for attainment purposes. In addition, a variety of mobile

source measures could be considered as part of the commitment to meet

the need for additional emission reduction measures.

6. Mid-Course Review

A mid-course review (MCR) is a reassessment of modeling analyses

and more recent monitored 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

dates.

The EPA believes that a commitment to perform a MCR is a critical

element of the WOE analysis for the attainment demonstration on which

EPA is proposing to take action today. In order to approve the

attainment demonstration SIP for the Baltimore area, EPA believes that

the State(s) must submit an enforceable commitment to perform a MCR as

described here.¹⁴

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\14\ For purposes of conformity, the State needs a commitment

that has been subject to 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.

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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, the States must have an enforceable commitment to

perform the MCR, preferably following the 2003 ozone season, and to

submit the results to EPA by the end of the review year (e.g. 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 an area attains the standard.

Therefore,

[[Page 70406]]

if EPA determines additional control measures are needed for

attainment, EPA would determine whether additional emission reductions

as necessary from States in which the nonattainment area is located or

upwind States, or both. The EPA would require the affected State or

States to adopt and submit the new measures within a period specified

at the 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 https://www.epa.gov/ttn/scram/.

D. In Summary, What Does EPA Expect to Happen with Respect to

Attainment Demonstrations for the Baltimore 1-Hour Ozone

Nonattainment Area?

The following table shows a summary of information on what EPA

expects from the State of Maryland to allow EPA to approve the 1-hour

ozone attainment demonstration SIP for the Baltimore area.

Table 3.--Summary Schedule of Future Actions Related To Attainment Demonstration for the Baltimore Severe

Nonattainment Area in Maryland and Which is Located in the OTR

----------------------------------------------------------------------------------------------------------------

Req'd no later than: Action

----------------------------------------------------------------------------------------------------------------

12/31/99......................................................... State submits the following to EPA:

--Motor vehicle emissions budget \1\

--Commitments \2\ or reaffirmation of

previous enforceable commitment to do the

following:

--Submit by 10/31/01 measures for additional

emission reductions as required in the

attainment demonstration test; for

additional emission reduction measures

developed through the regional process, the

State must also submit a commitment for the

additional measures and a backstop

commitment to adopt and submit by 10/31/01

intrastate measures for the emission

reductions in the event the OTR process does

not recommend measures that produce emission

reductions.

--Submit revised SIP & motor vehicle

emissions budget by 10/31/01 if additional

measures (due by 10/31/01) affect the motor

vehicle emissions inventory

--Revise SIP & motor vehicle emissions budget

1 year after MOBILE6 issued.\3\

--Perform a mid-course review.

--A list of potential control measures that

could provide additional emission reductions

needed to attain the standard \4\

4/15/00 State submits in final any submissions made in draft by

12/31/99.

Before EPA final rulemaking...................................... State submits enforceable commitments for any

above-mentioned commitments that may not yet

have been subjected to public hearing.

12/31/00......................................................... --State submits adopted modeled measures

relied on in attainment demonstration or

relied on for ROP through the attainment

year.

--State revises & submits SIP & motor vehicle

emissions budget to account for Tier 2

reductions as needed.\5\

10/31/01......................................................... --OTR States submit additional measures

developed through the regional process.

--State revises SIP & motor vehicle emissions

budget if the additional measures are for

motor vehicle category.

Within 1 yr after release of MOBILE6 model....................... State submits revised SIP & motor vehicle

emissions budget based on MOBILE6.

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 (the one

undergoing public process) may be submitted at this time with a final budget by 4/15/00. However, 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. 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\ As provided in the preamble text, the State may clarify by letter an existing commitment, which has been

subject to public hearing, to submit the control measures needed for attainment. If the State has not yet

submitted such a commitment, the State should adopt a commitment after public hearing. If the public hearing

process is not yet complete, then draft commitments may be submitted at this time. The final commitment should

be submitted no later than 4/15/00.

\3\ The revision for MOBILE6 is only required for SIPs that include the effects of Tier 2. The commitment to

revise the SIP after MOBILE6 may be submitted at the same time that the state submits the budget that includes

the effects of Tier 2 (no later than 12/31/00).

\4\ The State is not required to commit to adopt any specific measures. However, if the State does not do so,

the list cannot include any measures that place limits on highway construction.

\5\ If the state submits such a revision, it must be accompanied by a commitment to revise the SIP and motor

vehicle emissions budget 1 year after MOBILE6 is issued (if the commitment has not already been submitted).

E. What are the Relevant Policy and Guidance Documents?

This proposal cited several policy and guidance memoranda. The EPA

has also developed several technical documents related to the

rulemaking action in this proposal. Some of these documents have been

referenced above. These 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.

Approval and Promulgation of Air Quality Implementation Plans; Maryland; One-Hour Ozone Attainment Demonstration for the Baltimore Ozone Nonattainment Area

Federal Register Document

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Approval and Promulgation of Air Quality
Implementation Plans; Maryland;
One-Hour Ozone Attainment Demonstration
for the Baltimore Ozone Nonattainment Area