2428 Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations

218.602, 218.611; Subpart AA: 218.620,

218.623 (repealed); Subpart CC; Subpart

DD; Subpart PP: 218.920, 218.926;

Subpart QQ: 218.940, 218.946; Subpart

RR: 218.960, 218.966; Subpart TT:

218.980, 218.986; Subpart UU: 218.991.

These sections were adopted on January

6, 1994, Amended at 18 Ill. Reg. 1945,

effective January 24, 1994.

* * * * *

3. Section 52.741 is amended by

revising paragraph (a)(2) to read as

follows:

§ 52.741 Control Strategy: Ozone control

measures for Cook, DuPage, Kane, Lake,

McHenry or Will County.

(a) * * *

(2) Applicability.

(i) Effective October 11, 1994, Illinois

Administrative Code Title 35:

Environmental Protection, Subtitle B:

Air pollution, Chapter I: Pollution

Control Board, Subchapter c: Emissions

Standards and Limitations for

Stationary Sources, Part 218: Organic

Material Emission Standards and

Limitations for the Chicago Area

replaces the requirements of 40 CFR

52.741 Control strategy: Ozone control

measures for Cook, DuPage, Kane, Lake,

McHenry and Will County as the

federally enforceable control measures

in these counties except as noted in

paragraphs (a)(2)(i) (A) through (C) of

this section.

(A) Until March 26, 1996, Illinois’

major non-CTG sources in the Chicago

area, subject to paragraph u, v, w, or x

because of the applicability criteria in

these paragraphs, continue to be subject

to paragraphs u, v, w, x, and in addition

they remain subject to the

recordkeeping requirements in

paragraph y and any related parts of

section 52.741 necessary to implement

these paragraphs, e.g., those paragraphs

containing test methods, definitions,

etc.

(B) In accordance with Section

218.101(b), all FIP requirements remain

in effect and are enforceable after

October 11, 1994, for the period prior to

October 11, 1994 (and the major nonCTG FIP requirements specified in

paragraph (a)(2)(i)(A) remain in effect

and are enforceable after March 26, 1996

for the period prior to March 26, 1996.

(C) Any source that received a stay, as

indicated in Section 218.103(a)(2),

remains subject to the stay if still in

effect, or (if the stay is no longer in

effect) the federally promulgated rule

applicable to such source.

(ii) Effective March 26, 1996, Illinois

Administrative Code Title 35:

Environmental Protection, Subtitle B:

Air pollution, Chapter I: Pollution

Control Board, Subchapter c: Emissions

Standards and Limitations for

Stationary Sources, Part 218: Organic

Material Emission Standards and

Limitations for the Chicago Area

replaces the requirements of 40 CFR

52.741 Control strategy: Ozone control

measures for Cook, DuPage, Kane, Lake,

McHenry and Will County as the

federally enforceable control measures

in these counties except as noted in

paragraphs (a)(2)(ii) (A) and (B) of this

section.

(A) In accordance with Section

218.101(b), all major non-CTG FIP

requirements specified in paragraph

(a)(2)(i)(A) remain in effect and are

enforceable after March 26, 1996 for the

period prior to March 26, 1996.

(B) Any source that received a stay, as

indicated in Section 218.103(a)(2),

remains subject to the stay if still in

effect, or (if the stay is no longer in

effect) the federally promulgated rule

applicable to such source.

* * * * *

[FR Doc. 96–1297 Filed 1–25–96; 8:45 am]

BILLING CODE 6560–50–P

40 CFR Part 52

[IL99–2–7003, IN46–2–7004, MI33–2–7005,

WI47–2–7006; FRL–5402–8]

Approval of a Section 182(f)

Exemption; Illinois, Indiana, Michigan,

and Wisconsin

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Final rule.

SUMMARY: As requested by the States of

Illinois, Indiana, Michigan, and

Wisconsin in a July 13, 1994 submittal

pursuant to section 182(f)(3) of the

Clean Air Act (CAA or the Act), the EPA

is granting exemptions from the

Reasonably Available Control

Technology (RACT) and New Source

Review (NSR) requirements for major

stationary sources of Oxides of Nitrogen

(NOX) and from vehicle Inspection/

Maintenance (I/M) and general

conformity requirements for NOX for

ozone nonattainment areas within the

Lake Michigan Ozone Study (LMOS)

modeling domain, which includes

portions of the States of Illinois,

Indiana, Michigan, and Wisconsin. The

EPA is also granting exemptions from

transportation conformity requirements

for NOX for ozone nonattainment areas

classified as marginal or transitional

within the LMOS modeling domain.

The EPA is approving the exemptions

based on a demonstration that

additional NOX reductions would not

contribute to attainment of the National

Ambient Air Quality Standard (NAAQS)

for ozone within the LMOS modeling

domain. The EPA is not taking final

action at this time on the granting of

exemptions from the transportation

conformity requirements of the CAA for

ozone nonattainment areas classified as

moderate or above in the LMOS

modeling domain. The continued

approval of these exemptions is

contingent on the results of the final

ozone attainment demonstrations and

plans. These plans are expected to be

submitted by mid-1997 and to

incorporate the results of the Ozone

Transport Assessment Group process.

The attainment plans will supersede the

initial modeling information which is

the basis for the waiver EPA is granting

in this document. To the extent the

attainment plans include NOX controls

on certain major stationary sources in

the LMOS ozone nonattainment areas,

EPA will remove the NOX waiver for

those sources. To the extent the final

plans achieve attainment of the ozone

standard without additional NOX

reductions from certain sources, the

NOX emissions control exemption

would continue for those sources. EPA’s

rulemaking action to reconsider the

initial NOX waiver may occur

simultaneously with rulemaking action

on the attainment plans.

DATES: This final rule will be effective

February 26, 1996.

ADDRESSES: Copies of the exemption

request, public comments and EPA’s

responses are available for inspection at

the following address: United States

Environmental Protection Agency,

Region 5, Air and Radiation Division, 77

West Jackson Boulevard, Chicago,

Illinois 60604.

FOR FURTHER INFORMATION CONTACT:

Edward Doty, Regulation Development

Section (AR–18J), Regulation

Development Branch, Air and Radiation

Division, United States Environmental

Protection Agency, Region 5, 77 West

Jackson Boulevard, Chicago, Illinois

60604, Telephone Number (312) 886–

6057.

SUPPLEMENTARY INFORMATION:

I. Background Information

On July 13, 1994, the States of Illinois,

Indiana, Michigan, and Wisconsin

submitted a petition to the EPA

requesting that the ozone nonattainment

areas within the LMOS modeling

domain be exempted from requirements

to implement NOX controls pursuant to

section 182(f) of the Act. The exemption

request is based on modeling

demonstrating that additional NOX

emission controls within the

nonattainment areas will not contribute
Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations 2429

to attainment of the ozone NAAQS

within the LMOS modeling domain.

On March 6, 1995, EPA published a

rulemaking proposing approval of the

NOX exemption petition and

specifically identifying the Counties or

areas covered by the exemption. During

the 30 day public comment period, EPA

received a number of comments

favoring or objecting to the proposed

approval. In addition to these

comments, the EPA also received

adverse comments objecting to any NOX

control waiver within the United States,

with the commenters requesting that

these comments be addressed in all EPA

rulemakings dealing with such emission

control waivers.

II. Public Comments

The following discussion summarizes

the comments received regarding the

States’ petition and/or EPA’s proposed

rulemaking and presents EPA’s

responses to these comments.

Comment: A number of comments

supporting the proposed rulemaking

were received from organizations

representing various industrial groups,

local planning organizations, and the

States themselves. One commenter, who

generally supported the proposed

rulemaking, noted that the EPA

proposed to reverse its decision on the

petition if subsequent modeling results

supported such a reversal. The

commenter raised a concern that the

EPA should only reverse its decision to

approve the petition if well documented

modeling results are available clearly

indicating the need for such a reversal.

Response: The favorable comments

support the logic used in the proposed

rulemaking.

With regard to the concern over the

quality of the modeling results needed

to reverse this decision, it should be

noted that such modeling results will be

well documented and are expected to be

based on validated modeling. The States

involved in the LMOS are conducting a

number of additional modeling analyses

(subsequent to the preparation of the

NOX waiver request) to assess the

impacts of emission controls on peak

ozone concentrations and on ozone

concentrations transported out of the

modeling domain (long range ozone

transport has become a significant issue

in the development of ozone

demonstrations of attainment in the

eastern United States). Additional

modeling analyses are required to

support the States’ demonstrations of

attainment, which have not been

completed. These modeling analyses are

well documented and are now based on

a modeling system which has been

accepted by the EPA as being validated

for the LMOS modeling domain. Any

conclusion showing the need for NOX

controls will be well supported by the

modeling.

It should be noted that the modeling

used to support the NOX waiver petition

was not based initially on validated

modeling. The modeling system and its

base year inputs were modified to a

validated form subsequent to the

submittal of the petition. Nonetheless,

the ‘‘signals’’ of the modeling results

regarding Volatile Organic Compound

(VOC) controls versus NOX controls

have not changed with the validation of

the modeling system. The modeling

results continue to show that NOX

emission controls in the ozone

nonattainment areas will not contribute

to reduction of peak ozone levels within

the LMOS modeling domain, and may

actually increase peak ozone levels near

the major urban areas.

Comment: A commenter, who

supports the proposed NOX exemption,

considers the exemption, through

section 182(f), to also increase the major

source threshold relating to federal

operating permit programs from 25 tons/

year (tpy) to 100 tpy (this comment is

assumed to apply to the ozone

nonattainment areas classified as

severe).

Response: The commenter is correct.

Based on guidance contained in 40 CFR

Part 70.2 (subparagraph (3)(1) under the

‘‘major source’’ definition), the major

source threshold for federal operating

programs would be revised to 100 tpy,

potential to emit, in the areas covered

by the NOX waiver. In addition, for new

source considerations, it should be

noted that the waived areas should be

considered to be covered by Prevention

of Significant Deterioration

requirements, with a control source size

threshold of 250 tpy, potential to emit,

for NOX rather than by nonattainment

area new source requirements.

Comment: A commenter notes that, in

addition to modeling data supporting

approval of the petition, monitoring

data were collected during the 1991

LMOS field study which also support

the approval of the NOX waiver. The

combination of modeling data and

monitoring data meet the requirements

for a section 182(f) exemption specified

in EPA’s guidance documents titled:

‘‘State Implementation Plan; Nitrogen

Oxides Implementation of Title I of the

Clean Air Act Amendments of 1990’’ (57

FR 55628, November 25, 1992); and the

‘‘Guideline for Determining

Applicability of Nitrogen Oxide

Requirement under Section 182(f)’’

(December 1993).

Response: Although the commenter

did not specifically reference the data

from which this conclusion was drawn,

EPA acknowledges that data, such as

concentrations of non-methane

hydrocarbons and NOX and derived/

monitored ozone production potentials

of air parcels, collected for the urban

source areas during the 1991 field study

support the approval of the NOX waiver.

It is noted, however, that the primary

basis for the approval of the N0x waiver

is the modeling results submitted in

support of the waiver. The 1991 field

data by themselves may not be an

adequate support for the waiver since

these data are limited in nature and do

not present a complete picture of the

impacts of NOX controls on LMOS

modeling domain peak ozone

concentrations.

Comment: Commenters argue that

NOX exemptions are provided for in two

separate parts of the Act, in sections

182(b)(1) and 182(f). Because the NOX

exemption tests in sections 182(b)(1)

and 182(f)(1) include language

indicating that action on such requests

should take place ‘‘when [EPA]

approves a plan or plan revision,’’ these

commenters conclude that all NOX

exemption determinations by the EPA,

including exemption actions taken

under the petition process established

by section 182(f)(3), must occur during

consideration of an approvable

attainment or maintenance plan, unless

the area has been redesignated as

attainment. The commenters also argue

that even if the petition procedures of

section 182(f)(3) may be used to relieve

areas of certain NOX requirements,

exemptions from the NOX conformity

requirements must follow the process

provided in section 182(b)(1), since this

is the only provision explicitly

referenced by section 176(c), the Act’s

conformity provisions.

Response: Section 182(f) contains

very few details regarding the

administrative procedures for acting on

NOX exemption requests. The absence

of specific guidelines by Congress leaves

the EPA with discretion to establish

reasonable procedures consistent with

the requirements of the Administrative

Procedure Act (APA).

The EPA disagrees with the

commenters regarding the process for

considering NOX exemption requests

under section 182(f), and instead

believes that sections 182(f)(1) and

182(f)(3) provide independent

procedures by which the EPA may act

on NOX exemption requests. The

language in section 182(f)(1), which

indicates that the EPA should act on

NOX exemptions in conjunction with

action on a plan or a plan revision, does

not appear in section 182(f)(3). While

section 182(f)(3) references section
2430 Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations

182(f)(1), the EPA believes that this

reference encompasses only the

substantive tests in paragraph (1) [and

by extension, paragraph (2)], not the

procedural requirement that the EPA act

on exemptions only when acting on

State Implementation Plans (SIPs).

Additionally, section 182(f)(3) provides

that ‘‘person[s]’’ [which section 302(e)

of the Act defines to include States] may

petition for NOX exemptions ‘‘at any

time,’’ and requires the EPA to make its

determination within six months of the

petition’s submission. These key

differences lead EPA to believe that

Congress intended the exemption

petition process of paragraph (3) to be

distinct and more expeditious than the

longer plan revision process intended

under paragraph (1).

With respect to major stationary

sources, section 182(f) requires States to

adopt NOX RACT and NSR rules, unless

exempted. These rules were generally

due to be submitted to the EPA by

November 15, 1992. Thus, in order to

avoid the CAA sanctions, areas seeking

a NOX exemption would have needed to

submit this exemption request for EPA

review and rulemaking action several

months before November 15, 1992. In

contrast, the CAA specifies that the

attainment demonstrations were not due

until November 1993 or 1994 (and EPA

may take 12 to 18 months to approve or

disapprove the demonstrations). For

marginal ozone nonattainment areas

(subject to NOX NSR), no attainment

demonstrations are called for in the

CAA. For areas seeking redesignation to

attainment of the ozone NAAQS, the

CAA does not specify a deadline for

submittal of maintenance

demonstrations (in reality, EPA would

generally consider redesignation

requests without accompanying

maintenance plans to be unacceptable).

Clearly, the CAA envisions the

submittal of and EPA action on NOX

exemption requests, in some cases, prior

to submittal of attainment or

maintenance demonstrations.

With respect to the comment that

section 182(b)(1) is the appropriate

authority for granting interim-period

transportation conformity NOX

exemptions, EPA agrees with the

commenters and has published an

interim final rule that changes the

transportation conformity rule’s

reference to section 182(b)(1) as the

correct authority under the Act for

waiving the NOX build/no-build and

less-than-1990 emissions tests for

certain areas. See 60 FR 44762 (A

related proposed rule, 60 FR 44790,

published on the same day, invited

public comment on how the Agency

plans to implement section 182(b)(1)

transportation conformity NOX

exemptions. That proposal has been

subsequently finalized. See 60 FR

57179). However, EPA also notes that

section 182(b)(1), by its terms, only

applies to moderate and above ozone

nonattainment areas. Consequently,

EPA believes that the interim-reductions

requirements of section 176(c)(3)(A)(iii),

and hence the authority provided in

section 182(b)(1) to grant relief from

those interim-reduction requirements,

apply only with respect to those areas

that are subject to section 182(b)(1). EPA

intends to continue to apply the

transportation conformity rule’s build/

no-build and less-than-1990 emissions

tests for purposes of implementing the

requirements of section 176(c)(1), and

EPA intends to continue to provide

relief from those requirements under

section 182(f). In addition, because

general federal actions are not subject to

section 176(c)(3)(A)(iii), which

explicitly references section 182(b)(1),

EPA will also continue to offer relief

under section 182(f)(3) from the

applicable NOX requirements of the

general conformity rule.

In order to demonstrate conformity,

transportation-related federal actions

that are taken in ozone nonattainment

areas not subject to section 182(b)(1)

and, hence, not subject to section

176(c)(3)(A)(iii) must still be consistent

with the criteria specified under section

176(c)(1). Specifically, these actions

must not, with respect to any standard,

cause or contribute to new violations,

increase the frequency or severity of

existing violations, or delay attainment.

In addition, such actions must comply

with the relevant requirements and

milestones contained in the applicable

state implementation plan, such as

reasonable further progress schedules,

assumptions specified in the attainment

or maintenance demonstrations,

numerical emission limits, or

prohibitions. EPA believes that the

build/no-build and less-than-1990

emissions tests provide an appropriate

basis for such areas to demonstrate

compliance with the above criteria.

As noted earlier, EPA intends to

continue to offer relief under section

182(f) from the interim NOX

requirements of the conformity rules

that would apply under section

176(c)(1) for the areas not subject to

section 182(b)(1) in the manner

described above. EPA believes this

approach is consistent both with the

way NOX requirements in ozone

nonattainment areas are treated under

the Act generally, and under section

182(f) in particular. The basic approach

of the Act is that NOX reductions should

apply when beneficial to an area’s

attainment goals, and should not apply

when unhelpful or counterproductive.

Section 182(f) reflects this approach but

also includes specific substantive tests

which provide a basis for EPA to

determine when NOX requirements

should not apply. There is no

substantive difference between the

technical analysis required to make an

assessment of NOX impacts on

attainment in a particular area whether

undertaken with respect to mobile

source or stationary source NOX

emissions. Moreover, where EPA has

determined that NOX reductions will

not benefit attainment or would be

counterproductive in an area, the EPA

believes it would be unreasonable to

insist on NOX reductions for purposes of

meeting reasonable further progress or

other milestone requirements. Thus,

even as to the conformity requirements

of section 176(c)(1), EPA believes it is

reasonable and appropriate, first, to

offer relief from the applicable NOX

requirements of the general and

transportation conformity rules in areas

where such reductions would not be

beneficial and, second, to rely in doing

so based on the exemption tests

provided in section 182(f).

For moderate and above ozone

nonattainment areas which are relying

on modeling data in petitioning for a

transportation conformity NOX

exemption, the proposed change affects

the process for applying for such

waivers. Unlike section 182(f)(3),

section 182(b)(1) requires that EPA

approve a NOX waiver (i.e., determine

that additional reductions of NOX

would not contribute to attainment) as

part of a SIP revision. Thus, under

section 182(b)(1), petitions for

transportation conformity NOX waivers

for areas subject to that section must be

submitted as formal SIP revisions by the

Governor (or designee) following a

public hearing. As explained

previously, EPA will continue to

process and approve, under section

182(f)(3), conformity NOX waivers for

areas not subject to section 182(b)(1)

without public hearings or submission

by the Governor. Finally, as noted

earlier, the NOX provisions of the

general conformity rule would not be

affected by this proposal. A NOX waiver

under section 182(f) removes the NOX

general conformity requirements

entirely and would continue to do so.

The Clean Air Act’s provision for

transportation conformity NOX waivers

stems from section 176(c)(3)(A)(iii),

which addresses only transportation

conformity, and not general conformity.

Therefore, the statutory authority for

general conformity NOX waivers is not
Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations 2431

required to be section 182(b) for any

areas and may continue to be section

182(f) for all areas.

It should be noted that EPA is taking

no final action on a NOX exemption for

transportation conformity for ozone

nonattainment areas classified as

moderate and above in the petition

covered by this rulemaking. The States

of Illinois, Indiana, Michigan, and

Wisconsin may seek a transportation

conformity NOX exemption for such

areas through formal SIP revisions

pursuant to section 182(b)(1) of the Act

(Illinois and Wisconsin have submitted

such SIP revisions, which are currently

being reviewed by the EPA).

Comment: Commenters argue that

waiver of NOX control requirements is

unlawful if such a waiver would impede

attainment and maintenance of the

ozone standard in downwind areas.

Response: As a result of these

comments, the EPA reevaluated its

position on this issue and has revised

the previously issued guidance. See

Memorandum, ‘‘Section 182(f) Nitrogen

Oxides (NOX) Exemptions—Revised

Process and Criteria’’ dated February 8,

1995, for John Seitz’s signature. As

described in this memorandum, EPA

intends to use its authority under

section 110(a)(2)(D) to require a State to

reduce NOX emissions from stationary

and/or mobile sources where there is

evidence, such as photochemical grid

modeling, showing that the NOX

emissions could contribute significantly

to nonattainment in, or interfere with

maintenance by, any other State or in

another nonattainment area within the

same State. This action would be

independent of any action taken by EPA

on a NOX exemption request under

section 182(f). That is, EPA action to

grant or deny a NOX exemption request

under section 182(f) for any area would

not shield that area from EPA action to

require NOX emission reductions, if

necessary, under section 110(a)(2)(D).

Significant new modeling analyses are

being conducted by the Lake Michigan

Air Directors Consortium (LADCO) (the

technical and functional directors of the

Lake Michigan Ozone Study and the

Lake Michigan Ozone Control Program,

including representatives of the four

LMOS States and the EPA), EPA and

other agencies as part of the Ozone

Transport Assessment Group (OTAG)

process. The OTAG process is a

consultative process among the eastern

States and EPA. The OTAG process,

which ends at the close of 1996,

assesses national and regional emission

control strategies using improved

modeling techniques. The goal of the

OTAG process is for EPA and the

affected States to reach consensus on

the additional regional and national

emission reductions that are needed for

attainment of the ozone standard. Based

on the results of the OTAG process,

States are expected to submit by mid1997 attainment plans which show

attainment of the ozone standard

through local, regional, and national

controls.

The OTAG plans to complete

additional modeling between now and

September 1996 using emissions data

and strategies currently being developed

among OTAG workgroups. These new

analyses will improve the information

available on NOX and VOC impacts on

ozone concentrations both in the LMOS

area and over the eastern half of the

United States. These analyses will for

example, provide more accurate

boundary conditions for the LMOS area

analyses; this provides greater accuracy

in both the attainment plan and in the

decision regarding NOX reductions

contribution to attainment.

In light of the modeling completed

thus far and considering the importance

of the OTAG process and attainment

plan modeling efforts, EPA is granting

this waiver on a contingent basis. As the

OTAG modeling results and control

recommendations are completed in

1996, this information will be

incorporated into the attainment plans

being developed by the LADCO States.

When these attainment plans are

submitted to EPA in mid-1997, these

new modeling analyses will be reviewed

to determine if the NOX waiver should

be continued, altered, or removed.

The attainment plans will supersede

the initial modelling results which are

the basis for the waiver which EPA is

granting in this rule. To the extent the

attainment plans include NOX controls

on certain major stationary sources in

the LMOS ozone nonattainment areas,

EPA will remove the NOX waiver for

those sources. To the extent the plans

achieve attainment without additional

NOX reductions from certain sources,

the NOX reductions would be

considered excess reductions and, thus,

the exemption would continue for those

sources. EPA’s rulemaking action to

reconsider the initial NOX waiver may

occur simultaneously with rulemaking

action on the attainment plans.

Comment: Comments were received

regarding the scope of exemption of

areas from the NOX requirements of the

conformity rules. The commenters argue

that such exemptions waive only the

requirements of section 182(b)(1) to

contribute to specific annual reductions;

not the requirement that conformity

SIPs contain information showing the

maximum amount of motor vehicle NOX

emissions allowed under the

transportation conformity rules and,

similarly, the maximum allowable

amounts of any such NOX emissions

under the general conformity rules. The

commenters admit that, in prior

guidance, EPA has acknowledged the

need to amend a drafting error in the

existing transportation conformity rules

to ensure consistency with motor

vehicle emissions budgets for NOX, but

want EPA, in actions on NOX

exemptions, to explicitly affirm this

obligation and to also avoid granting

waivers until a budget controlling future

NOX increases is in place.

Response: As explained previously,

EPA’s transportation conformity rule

originally provided for a NOX waiver if

an area received a section 182(f)

exemption. The EPA published

amendments to the transportation

conformity rule in a final rule on

November 14, 1995 (60 FR 57179)

which addresses the issue of conformity

to NOX budgets in SIPs when a NOX

waiver for transportation conformity has

been approved. The final rule is based

on an August 29, 1995 (60 FR 44790)

proposed rule and comments which

were received regarding that proposal.

The final rule requires consistency with

NOX motor vehicle emissions budgets in

control strategy SIPs regardless of

whether a NOX waiver has been granted.

The NOX build/no-build tests and lessthan-1990 tests, however, no longer

apply to ozone nonattainment areas

receiving a NOX waiver. Furthermore,

some flexibility is possible for areas that

have been issued a NOX waiver based

on air quality modeling data. This

flexibility is described in the notice of

final rulemaking (60 FR 57183). The

NOX emission budget provisions of the

revised rules will be effective 90 days

after the date of the final rule

(November 14, 1995).

Comment: Commenters argue that the

Act does not authorize any waiver of the

NOX reduction requirements until

conclusive evidence exists that such

reductions are counterproductive.

Response: EPA does not agree with

this comment since it ignores the

Congressional intent as evidenced by

the plain language of section 182(f), the

structure of the Title I ozone subpart as

a whole, and relevant legislative history.

By contrast, in developing and

implementing its NOX exemption

policies, EPA has sought an approach

that reasonably accords with that intent.

Section 182(f), in addition to imposing

control requirements on major

stationary sources of NOX similar to

those that apply for sources of VOC, also

provides for an exemption (or

limitation) from application of these

requirements if, under one of several
2432 Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations

tests, EPA determines that in certain

areas NOX reductions would generally

not be beneficial towards attainment of

the ozone standard. In section 182(f)(1),

Congress explicitly conditioned action

on NOX exemptions on the results of an

ozone precursor study required under

section 185B of the Act. Because of the

possibility that reducing NOX in an area

may either not contribute to ozone

attainment or may cause the ozone

problem to worsen, Congress included

attenuating language, not just in section

182(f), but throughout Title I of the Act,

to avoid requiring NOX reductions

where such would not be beneficial or

would be counterproductive. In

describing these various ozone

provisions, including section 182(f), the

House Conference Committee Report

states in the pertinent part: ‘‘[T]he

Committee included a separate NOX/

VOC study provision in section [185B]

to serve as the basis for the various

findings contemplated in the NOX

provisions. The Committee does not

intend NOX reduction for reduction’s

sake, but rather as a measure scaled to

the value of NOX reductions for

achieving attainment in the particular

ozone nonattainment area.’’ H.R. Rep.

No. 490, 101st Cong., 2d Sess. 257–258

(1990).

As noted in response to an earlier

comment, the command in section

182(f)(1) that EPA ‘‘shall consider’’ the

185B report taken together with the

timeframe the Act provides for

completion of the report and for acting

on NOX exemption petitions clearly

demonstrate that Congress believed the

information in the completed section

185B report would provide a sufficient

basis for EPA to act on NOX exemption

requests, even absent the additional

information that would be included in

affected areas’ attainment or

maintenance demonstrations.

While there is no specific requirement

in the Act that EPA actions granting

NOX exemption requests must await

‘‘conclusive evidence,’’ as the

commenters argue, there is also nothing

in the Act to prevent EPA from

revisiting an approved NOX exemption

if warranted by additional, current

information.

In addition, the EPA believes, as

described in EPA’s December 1993

guidance, that section 182(f)(1) of the

Act provides that the new NOX

requirements shall not apply (or may be

limited to the extent necessary to avoid

excess reductions) if the Administrator

determines that any one of the following

tests is met:

(1) in any area, the net air quality

benefits are greater in the absence of

NOX reductions from the sources

concerned;

(2) in nonattainment areas not within

an ozone transport region, additional

NOX reductions would not contribute to

ozone attainment in the area; or

(3) in nonattainment areas within an

ozone transport region, additional NOX

reductions would not produce net ozone

air quality benefits in the transport

region. Based on the plain language of

section 182(f), EPA believes that each

test provides an independent basis for a

full or limited NOX exemption.

Only the first test listed above is

based on a showing that NOX reductions

are ‘‘counter productive.’’ If one of the

tests is met (even if another test is failed

or not applied), the section 182(f) NOX

requirements would not apply or, under

the excess reductions provision, a

portion of these requirements would not

apply.

Comment: Commenters argue that,

while NOX controls may be less

beneficial than VOC-only controls in

reducing ozone concentrations in some

areas of the Lake Michigan region on

some days, the States have not

demonstrated that VOC-only controls

will sufficiently reduce ozone

concentrations for the majority of

episodes, particularly in areas farther

downwind.

Response: Several modeling and data

analyses were performed by the States

and LADCO to examine the relative

benefits of VOC versus NOX emission

controls. The modeling analyses

included emissions sensitivity tests for

several different basecase scenarios,

including: (1) an original base period

emissions inventory; (2) increased VOC

emissions in the base period inventory

(higher VOC/NOX ratios); (3) increased

base period VOC/NOX ratios through

either increased VOC emissions or

decreased NOX emissions; and (4)

differences in photochemistry

photolysis rates as applied in the Urban

Airshed Model—Version IV (UAM–IV)

(the photochemical dispersion model

generally accepted and supported by the

EPA) and in UAM–V (the

photochemical dispersion model

approved by the EPA for use in the

LMOS).

Despite differences in the absolute

and relative amounts of VOC and NOX

emissions in the sensitivity analyses,

the analyses found that the modeled

domain-wide peak ozone concentration,

the areal coverage of modeled ozone

concentrations exceeding 120 parts per

billion (ppb), and the number of hours

with modeled ozone concentrations

exceeding 120 ppb decreased in

response to VOC emission reductions

and increased in response to NOX

emission reductions (up to more than 60

percent controls for some episode

analysis days) for all modeled episodes.

VOC and NOX emission reductions

were found to produce different impacts

spatially. In and downwind of major

urban areas, within the ozone

nonattainment areas, VOC reductions

were effective in lowering peak ozone

concentrations, while NOX emission

reductions resulted in increased peak

ozone concentrations. Farther

downwind, within attainment areas,

VOC emissions reductions became less

effective for reducing ozone

concentrations, while NOX emission

reductions were effective in lowering

ozone concentrations. It must be noted,

however, that the magnitude of ozone

decreases farther downwind due to NOX

emission reductions was less than the

magnitude of ozone increases in the

ozone nonattainment areas as a result of

the same NOX emission reductions.

Analyses of ambient data by LMOS

contractors provided results which

corroborated the modeling results.

These analyses identified areas of VOCand NOX-limited conditions (VOClimited conditions would imply a

greater sensitivity of ozone

concentrations to changes in VOC

emissions. The reverse would be true for

NOX-limited conditions.) and tracked

the ozone and ozone precursor

concentrations in the urban plumes as

they moved downwind. The analyses

indicated VOC-limited conditions in the

Chicago/Northwest Indiana and

Milwaukee areas and NOX-limited

conditions further downwind. These

results imply that VOC controls in the

Chicago/Northwest Indiana and

Milwaukee areas would be more

effective at reducing peak ozone

concentrations within the severe ozone

nonattainment areas.

The consistency between the

modeling results and the ambient data

analysis results for all episodes with

joint data supports the view that the

UAM–V modeling system developed in

the LMOS may be used to investigate

the relative merits of VOC versus NOX

emission controls. The UAM–V results

for all modeled episodes point to the

benefits of VOC controls versus NOX

controls in reducing the modeled

domain peak ozone concentrations.

Comment: Commenters argue that the

UAM–V modeling system is

experimental and untested and has not

yet undergone extensive peer review by

independent experts, unlike the

Regional Oxidant Model (ROM)

supported by the EPA. The EPA should

review the ROM results for the episodes

modeled in the LMOS to show
Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations 2433

consistency between the ROM results

and those for UAM–V.

Response: Even though the UAM–V

modeling system is relatively new, it

has undergone external review. LADCO

supported an external review of the

computer code used in the modeling

system and an external evaluation of

model performance in the Lake

Michigan region. Modeling results show

that the system, as it is currently being

used for control strategy analyses,

produces ozone concentrations which

meet EPA-established criteria for

adequate model performance.

Direct comparisons of ROM and

UAM–V results must be conducted with

caution and may produce conflicting

results even though both modeling

systems are performing adequately. The

UAM–V modeling system is

theoretically more complete and

incorporates improved scientific

principles and more area-specific input

data. ROM, on the other hand, is a

simpler modeling system with lower

spatial resolution, more uncertain

emission estimates, and no special

treatment of meteorological phenomena,

such as lake-breeze effects (critical

factors in the Lake Michigan area), and

individual source plumes for large

sources. These differences in model

formulation and data input resolution as

well as differences in output resolution

may preclude direct comparisons of the

two models. It should be noted, that

such a comparison may be attempted in

the near future because UAM–V may be

applied to a larger domain to assess the

impacts of long range transport of ozone

and ozone precursors.

Comment: Commenters state that the

EPA must rely on the recent National

Academy of Sciences (NAS) report in its

review of NOX waivers. The

commenters pointed out that the NAS

report found that to reduce transported

ozone, NOX reductions are needed.

Response: The NAS report and EPA’s

companion report both support the

conclusion that, as a general matter for

ozone nonattainment areas across the

country, NOX reductions in addition to

VOC reductions will be needed to

achieve attainment. This general

conclusion, however, must be assessed

in the context of the more detailed

analysis provided in those same reports.

For example, the NAS report notes that

NOX reductions can have either a

beneficial or detrimental effect on ozone

concentrations, depending on the

locations and emission rates of VOC and

NOX sources in a region. The effect of

NOX reductions depends on the local

VOC/NOX ratio and a variety of other

factors. In its report issued pursuant to

section 185B of the Act, EPA stated that

‘‘[a]pplication of gridded photochemical

models on a case by case basis is

required to determine the efficacy of

NOX controls, because the ozone

response to precursor reductions is area

specific.’’

The analyses performed in the Lake

Michigan region demonstrate a local

disbenefit from NOX control in the

urban nonattainment areas. Those same

analyses suggest there would be ozone

benefits experienced farther downwind

from NOX control in the urban

nonattainment areas. LADCO

acknowledges that NOX controls in the

LMOS modeling domain may be needed

ultimately to reduce ozone transport in

the eastern United States. Nonetheless,

the modeling results show that, due to

the ozone reduction disbenefits

associated with NOX reductions for the

ozone nonattainment areas in the LMOS

domain, these areas meet the test under

section 182(f)(1)(A) of the Act required

to support a waiver from the NOX

requirements of section 182(f).

Comment: Commenters believe that

NOX emission reductions will not only

reduce transported ozone, but will also

improve visibility, especially in

downwind Class I areas.

Response: The NOX control waiver

request was submitted in conjunction

with the preparation of a four-State

ozone control plan. To this end, the

focus is on the local ozone problem in

the Lake Michigan region. Other air

pollution problems will be dealt with as

part of separate regulatory activities.

Comment: Commenters argue that the

burden of proof is on the States and

LADCO to demonstrate that NOX

reductions will not be beneficial over

the entire Lake Michigan region. It was

the explicit intent of Congress that NOX

reductions are to be presumed to be

beneficial unless demonstrated

otherwise.

Response: Modeling and data analyses

addressed in the States’ NOX waiver

request demonstrate the positive

benefits of VOC control in the major

urban areas and downwind in the areas

of highest ozone concentrations. These

analyses also show the negative effects

of NOX control in these same ozone

nonattainment areas, and suggest

positive benefits from NOX control

farther downwind in attainment areas.

In other words, the benefits resulting

from NOX control are modelled to occur

in areas that experience, based on

modeling and monitoring data, ozone

concentrations well below the ozone

standard even prior to the

implementation of emission controls.

Consequently, as required under section

182(f), the States have demonstrated the

disbenefits of implementing NOX

emission controls in terms of greater

domain-wide peak ozone concentrations

throughout the LMOS modeling

domain. Since these States are relying

on the section 182(f)(1)(4) ‘‘contribute to

attainment’’ test, they do not also need

to demonstrate NOX reduction benefits

over the entire Lake Michigan region as

the commenters claim.

As noted above, the EPA believes, as

described in EPA’s December 1993

guidance, that section 182(f)(1) of the

Act provides that the new NOX

requirements shall not apply if the

Administrator determines that any one

of the following tests is met:

(1) in any area, the net air quality

benefits are greater in the absence of

NOX reductions from the sources

concerned;

(2) in nonattainment areas not within

an ozone transport region, additional

NOX reductions would not contribute to

ozone attainment in the area; or

(3) in nonattainment areas within an

ozone transport region, additional NOX

reductions would not produce net ozone

air quality benefits in the transport

region. Based on the plain language of

section 182(f) and the modeling results

supplied with the LMOS States’ NOX

waiver request, the EPA believes these

States have met the requirements of test

(2) above since the States have

demonstrated that across-the-board NOX

controls in the LMOS ozone

nonattainment areas will interfere with

the attainment of the ozone standard in

these nonattainment areas. Based on the

scheme provided by Congress under the

Act, it is not necessary for the States to

also demonstrate the lack of ozone

benefits from NOX controls everywhere

within the entire Lake Michigan region.

As a separate matter and as noted

above, the States, LADCO, and the EPA

are conducting additional studies on the

impact of ozone precursor (including

NOX) emission reductions in areas

outside of the LMOS ozone

nonattainment areas on downwind

ozone concentrations. These studies, in

part, will consider the LMOS

nonattainment areas as downwind areas

to assess the impact of upwind

emissions controls on ozone and ozone

precursor transport into these areas.

Comment: Commenters argue that

LADCO’s statistical comparisons

provide an incomplete evaluation of

model performance and do not assess

the model’s ability to accurately predict

the impact of VOC versus NOX control.

Response: LADCO, through a

September 1994 model evaluation

report, has documented a thorough

evaluation of the modeling system

performance. The model evaluation,

which is based on an ideal model
2434 Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations

1 ‘‘A Conceptual Framework for Evaluating the

Performance of Grid-Based Photochemical Air

Quality Simulation Models’’, Roth, Reynolds,

Tesche, and Dennis (1991).

evaluation process proposed by a

number of technical experts 1, includes

the following elements:

(1) Evaluations of the scientific

formulation of the model;

(2) Assessment of the fidelity of the

computer codes to scientific

formulation, governing equations, and

numerical solution procedures;

(3) evaluation of the predictive

performance of the individual process

modules and preprocessor modules;

(4) evaluation of the full model’s

predictive performance;

(5) application of sensitivity tests to

assure conformance of the model with

known or expected behavior;

(6) application of comparative

modeling; and

(7) implementation of quality control/

quality assurance activities.

The September 1994 model

evaluation report addressed all of these

elements for the modeling system used

in the LMOS. In addition, the report

also discussed several analyses which

were performed specifically to assess

the reliability of the model’s response to

VOC and NOX emission reductions (see

response to comment above concerning

the response of the model to VOC-only

controls).

The model evaluation conducted for

the LMOS modeling system examined

performance over as wide a range of

emission densities as possible (both

spatial and temporal ranges were

considered), considered topographic

and land use uncertainties, and

evaluated the impacts of variations in

meteorology. Demonstration of

acceptable model performance over this

range of conditions reflects correct

representation of the governing

chemical and physical processes. It is,

therefore, reasonable to assume that the

model will respond realistically

irrespective of emission strengths of

VOC versus NOX.

Comment: Commenters argue that

LADCO has failed to conduct additional

analyses of model performance which

provide a better test of VOC-NOX

sensitivity [e.g., analyses of afternoon

concentrations of total reactive nitrogen

(NOy)]. An examination of ambient NOX

concentrations over Lake Michigan

clearly show NOX-limited conditions

(i.e., NOX control should be beneficial

for reducing ozone concentrations) and,

further, that the modeled NOX

concentrations are overestimated, which

would cause the model to incorrectly

identify VOC control as being

preferential to NOX control. NOX

concentrations, as predicted by the

model to occur over Lake Michigan (i.e.,

90 parts per billion), are unlikely to

occur anywhere other than in urban

centers.

Response: The September 1994 model

evaluation report submitted by LADCO

does include the type of analysis

suggested by the commenters. This

analysis of predicted and measured NO2

concentrations (NOy concentrations

were not measured making evaluation of

modeled results for NOy impossible.

NOX is assumed to be primarily NO2 at

the peak ozone times and locations.) at

the time and location of maximum

ozone concentration for each day shows

no discernible bias in the model

predictions.

The September 1994 model

evaluation report also includes a general

assessment of model performance for

NO2. Rather than focusing on just one or

two days, as was done by the

commenters, the evaluation considered

all of the modeled high ozone days. The

results for all high ozone days

demonstrate that model performance

overall for NO2 is good.

The magnitude of the predicted NOX

concentrations over Lake Michigan, as

cited by the commenters, is not correct.

The model predicted NO2

concentrations over Lake Michigan on

the order of 50 parts per billion or less.

NOX measurements by the LMOS

aircraft over Lake Michigan were on the

order of 30—50 parts per billion, in

good agreement with the model’s

predicted concentrations (NOX over

Lake Michigan is primarily NO2).

Comment: Commenters argue that

VOC emissions are likely

underestimated in the emission

inventory used for the LMOS modeling,

which would cause a bias in the model

towards favoring VOC control. Also,

LADCO’s finding that its VOC inventory

may be low by only 30 percent conflicts

with studies elsewhere which suggest a

high degree of underestimation.

Response: Several methods were used

by LADCO to evaluate the LMOS

emissions inventory, including

comparisons of ambient to emissionsbased nonmethane organic compound to

NOX (NMOC:NOX) ratios; comparisons

of ambient to emissions-based carbon

monoxide to NOX ratios; receptor

modeling; and comparisons of ambient

to model-based NMOC:NOX ratios.

These analyses for an initial emissions

inventory suggested a significant

underestimation of VOC emissions,

overestimation of NOX emissions, or

some combination of these two.

Consequently, LADCO conducted an

extensive re-evaluation of the emissions

inventory and made several

modifications. The resulting, final

emissions inventory was found to

compare more closely to the ambient

NMOC:NOX ratios (the ambient

NMOC:NOX ratios are only about 1.0—

1.5 times greater than the emissions

inventory-based NMOC:NOX ratios).

To assess the effect of the emissions

uncertainty on the model’s response to

VOC and NOX reductions, sensitivity

tests were performed with a higher

VOC:NOX ratio. The results of this

modeling were qualitatively the same

(NOX disbenefits were demonstrated for

attainment of the ozone standard) as

those found for the unadjusted

emissions inventory. Consequently, any

possible underestimation of VOC

emissions does not affect the

conclusions drawn concerning VOC

versus NOX controls.

With regard to the results of other

emissions studies, it should first be

noted that a certain degree of variability

of emissions ratios (NMOC:NOX) exists

depending of the locations of the studies

and the sources sampled. Application of

the results of these studies to the LMOS

source areas is not straight forward and

must be viewed to have a high degree

of uncertainty. The LMOS results

leading to the adjustment of emissions

and the favorable comparison of

modeled and monitored results lends

some credibility to the emissions used

in the LMOS.

Secondly, the LMOS States and

LADCO, based on the studies of mobile

source emissions conducted previously

in other areas, recognized the potential

for the underestimation of mobile

source VOC emissions. This recognition

was part of the basis for the comparison

of monitored and modeled emissions

and the modeling sensitivity studies

considering alternate NMOC:NOX ratios.

As indicated above, increased

NMOC:NOX ratios lead to the same

conclusions regarding the impacts of

VOC versus NOX emissions controls.

Comment: A commenter notes that

the problems with the LMOS modeling

are not ‘‘routine’’ model errors. The

LMOS model results, as presented in a

February 1994 report by Alpine

Geophysics, showed large errors in

comparison with measurements for

certain pollutant species and these

errors suggest a bias in favor of VOC

control and against NOX control. The

finding that the model systematically

overestimates NOy also suggests that the

model is biased in favor of VOC control.

Response: The commenter has chosen

to rely on outdated results from a

preliminary February 1994 model

evaluation report. Since then, as

documented, for example, in the
Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations 2435

September 1994 model evaluation

report submitted to the EPA by LADCO,

significant improvements have been

made in the modeling system and in its

inputs. (See also the discussions in

response to other comments regarding

the model’s performance.) The

improved modeling system and its

results make moot the concerns of the

commenter.

Comment: A commenter is concerned

about the quality of the multi-species

evaluation contained in the September

1994 model evaluation report. The

commenter notes that an interim report

indicated that the model performed

poorly in modeling the concentrations

of paraffins, frequently erring by a factor

of two or more. Such an error implies

that the model may be biased in favor

of VOC controls. The commenter further

notes that the September 1994 model

evaluation report fails to include a

significant discussion of multi-species

evaluations, particularly a discussion of

modeled versus measured paraffin

concentrations.

Response: The September 1994 report

does discuss the fact that multi-species

analyses were performed for the

updated modeling system and updated

input data. As noted above, the updated

model performed acceptably for the

prediction of species such as ozone,

NO2, NOX, and VOC:NOX. The report

did fail to discuss most other species

addressed in the model. LADCO has

acknowledged this failure, and has

offered to supply any data requested by

the EPA. LADCO, however, has

indicated, in its own responses to the

comments on the proposed approval of

the NOX waiver, that the multi-species

performance of the model has

significantly improved from past

versions of the modeling system and

input data. It is not clear how the

performance of the model regarding

prediction of paraffin concentrations

has changed.

Comment: A commenter notes that

the emissions inventory used in the

modeling underestimates emissions of

both anthropogenic and biogenic VOC

emissions. A particular deficiency is the

lack of any biogenic isoprene emissions

in the Chicago area. In addition, the

failure to evaluate model performance

for isoprene is especially important.

Models that recommend VOC-based

control strategies should be required to

demonstrate that they have not

underestimated ambient concentrations

of isoprene.

Response: As noted in a response to

a comment above, the current version of

the emissions inventory used in the

modeling reasonably agrees with the

ambient data. Although the current

LMOS emissions inventory does not

contain biogenic isoprene emissions,

calculations made by LADCO, as

discussed in LADCO’s response to this

comment, indicate that this does not

result in a significant change in the VOC

inventory (addition of biogenic isoprene

emissions would only increase the

regional VOC inventory by 1 percent or

less). Ambient VOC measurements also

reflect negligible isoprene

concentrations in the Chicago, Gary, and

Milwaukee urban areas. The lack of an

evaluation of isoprene concentrations

should not detract from the overall

assessment of model performance.

LADCO has noted that the EPArecommended emission factors for

biogenic isoprene are under review

nationally. LADCO has committed to

revise the emissions inventory if these

emission factors are changed

significantly, particularly if they are

significantly increased.

LADCO has noted that the UAM-V

modeling system has been thoroughly

evaluated. In fact this evaluation

significantly exceeds the requirements

of the EPA and exceeds the evaluations

employed for UAM in most other ozone

nonattainment areas in the United

States.

Comment: A commenter notes that

the September 1994 model evaluation

report fails to include modeled versus

measured NO2 concentrations from

locations that represent maximum

measured ozone concentrations. It is

also noted that two-thirds of the

modeled-measured data pairs that were

documented in the model evaluation

report lie outside of the factor-of-two

range implying poor agreement between

modeled and measured concentrations.

Response: LADCO notes that the

modeled versus measured NO2 data

were included in the final model

evaluation report (October 1994). These

data show that there is no discernible

bias in the model predictions.

Furthermore, only a few data pairs

reflect an overprediction by more than

a factor of two. Most of the data pairs

lie either within the factor-of-two range,

or reflect underprediction by more than

a factor-of-two (underprediction of NO2

would favor NOX control over VOC

control in reducing ozone

concentrations). Despite the possible

underprediction of some NO2

concentrations, the model continues to

show that NOX control provides

disbenefits for attainment of the ozone

standard in the LMOS domain.

Comment: It is noted that Table 7 in

the September 1994 model evaluation

report contains NOX data which differ

from those in a February 1994 model

evaluation report. It is also noted that

the September 1994 model evaluation

report also fails to include data for a

critical site (the Mid-Lake Boat) on July

18, 1991.

Response: The NOX values contained

in the February 1994 report did not

reflect the final quality-assured data for

the boat-based monitors used in the

1991 LMOS field study. The final data

were addressed in the September 1994

model evaluation report. Nevertheless,

no firm conclusions should be based on

the NOX data from the boats because

these data were found to be suspect.

Table 7 in the September 1994 report

did not include the Mid-Lake Boat data

for July 18, 1991 because the Boat

stopped collecting data on this day after

1600 Central Daylight Time (CDT). The

modeling domain-wide peak observed

and modeled concentrations, as noted in

Table 7, occurred after 1600 CDT. In any

case, the peak ozone concentration at

the Mid-Lake Boat on this day was 158

parts per billion (1400 CDT). The

magnitude of the NOX concentration for

this hour was still fairly high (13 parts

per billion), indicating that the air mass

may still have been VOC-limited, which

favors VOC control of upwind sources

over NOX control for the reduction of

ozone levels.

Comment: The February 1994 model

evaluation report contains evidence that

the mixing algorithm in UAM–V has

serious problems. In particular, the

model is overestimating ambient NOX

concentrations by a factor of three or

more during the mid-July 1991 episode.

Response: The September 1994 model

evaluation report shows that the model

performance statistics for NO2 (as noted

above, NOX over Lake Michigan is

primarily NO2 with little NO) during the

mid-July episode are reasonable. The

spatial concentration plots for NO2

show that the predicted values are

highest in the Chicago downtown area

and decrease downwind over Lake

Michigan. The latest baseline model

input data set (Basecase C) produces

significantly lower peak NO2

concentrations than did the earlier

baseline model input data set

considered by the commenter. The new

input data lead to results similar to

concentrations measured in aircraft over

Lake Michigan during the 1991 field

study.

Comment: A commenter claims that

the September 1994 model evaluation

report erroneously claims that 1991

field study NOy measurements were not

available and that most local afternoon

NOy is expected to be NO2.

Response: Contrary to the

commenter’s claims, NOy data were not

collected during the 1991 field program.

The only nitrogen species for which
2436 Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations

ambient data were collected were NO,

NO2, NOX, and peroxyacetlnitrate (PAN)

(collected at only a few sites). LADCO

responds and EPA agrees that, while

NOy reflects many nitrogen compounds,

NO2 is a reasonable surrogate for these

analyses.

Comment: Commenters note that

LADCO has requested and received EPA

approval to assume a future modeling

domain boundary peak ozone

concentration of 60 parts per billion. An

analysis of this assumption leads the

commenters to conclude that NOX

transported into the modeling domain

would have to be reduced by

approximately 66 percent from current

emission levels. Given the policy

established in the approval of the NOX

exemption petition, the commenters

question the feasibility of this boundary

condition assumption.

Response: It is true that the EPA has

approved the assumption of a future

modeling domain boundary ozone

concentration not exceeding 60 parts

per billion. It should be noted, however,

that this is a temporary assumption to

be used only in the initial phase of

ozone modeling needed to develop the

areas’ final ozone demonstrations of

attainment. Regional modeling over a

larger domain will be conducted to

better assess the level of ozone transport

in the Eastern United States. This

regional modeling will also assess the

impacts of possible national emission

control efforts to generally lower ozone

precursor emissions throughout this

area. The final phase of local ozone

modeling will use ozone boundary

conditions based on the regional

modeling.

It should also be noted that the EPA,

under section 110(a)(2)(D) of the Act,

may require additional NOX emission

controls in the areas exempted from

specific NOX control requirements

under section 182(f) of the Act. The

NOX emission reduction requirements

under section 110(a)(2)(D) may exceed

those under section 182(f) if the regional

modeling supports the need for such

emission reductions. The boundary

ozone concentration that will ultimately

be used in the final demonstrations of

attainment will be backed by adequate

ozone precursor emission reductions.

Comment: Commenters argue that the

NOX exemption petition ignores the

LMOS States’ contribution to their own

boundary conditions. Insufficient

analyses have been presented that

consider the benefits in lowered

boundary ozone levels that could be

achieved during episodes when locally

generated ozone and ozone precursors

are transported out of and back into the

modeling domain. Exceedances

observed on June 18, 1994 are of note

in this regard. On this day, it appears

that the Chicago/Gary ‘‘plume’’ actually

moved north-northeast only to later

reimpose itself on the metropolitan area.

The benefits for NOX control are not

presented for this meteorological

phenomenon.

Response: Modeling for LMOS

considered all high ozone episodes in

1991. Modeling for these episodes will

form the basis for the ultimate ozone

demonstrations of attainment to be

completed in 1997 under current EPA

policy. The NOX exemption petition is

based on modeling for all of these high

ozone episodes, and, as such, meets the

modeling requirements in the December

1993 EPA guidance. It should be noted

that the episodes considered cover a

significant range of meteorological

phenomena, including ozone transport

and recirculation within the LMOS

domain. A more complete picture of

ozone transport out of and back into the

modeling domain will not be available

until after the completion of the regional

modeling discussed in the response to

the previous comment.

Comment: A commenter argues that

incorporating the Michigan Counties of

Saginaw, Bay, Genessee, Shiawasse,

Midland, Ingham, Jackson, Lenawee,

and Calhoun is an attempt to

factitiously expand the domain of

LADCO’s NOX disbenefit analysis. It is

also noted that the EPA has included

the fictional Michigan County of

Hillside. The commenter argues that, if

EPA had intended to exempt Hillsdale

County rather than ‘‘Hillside County,’’

the EPA should publish a correction

notice amending the proposed

rulemaking notice.

Response: When LADCO conducted

the modeling analysis of NOX control

impacts, NOX controls were modeled

using the LMOS intermediate modeling

domain (Grid B). The Counties noted by

the commenter are located outside of

Grid B. Therefore, LADCO did not

determine as part of this modeling effort

the potential ozone impacts of NOX

emission reductions for these Counties.

It can be noted, however, that the EPA

has received and reviewed base period

modeling for the larger domain (Grid A)

which did include the Counties in

question. Base period (1991) modeling

of high ozone episodes in the LMOS

domain has been determined by the

EPA to be validated based on

comparison of monitored and modeled

ozone concentrations. Modeling results

in Grid A in the Counties in question

and in their downwind environs shows

that the ozone standard is not violated

in these areas. This is confirmed by

monitoring data collected in 1991

during the LMOS field study. Based on

this observation, it can be concluded

that additional NOX emission controls

in these Counties would not contribute

to attainment of the ozone standard.

Therefore, under the ‘‘contribute to

attainment’’ test of section 182(f), the

NOX waiver should be approved for

these Counties. It should also be noted

that emission reductions in the

‘‘additional’’ Counties are not likely to

significantly impact peak ozone

concentrations in the LMOS modeling

domain. (Emission reductions in these

Counties, however, may be shown in

future regional modeling to lower ozone

transport into other ozone

nonattainment areas. If such is the case,

the State of Michigan may wish to or be

requested to consider additional

emission controls for these Counties.) A

definitive conclusion can not be made

here since the ozone and precursors

generated by the these Counties are

transported out of the modeling domain

for most modeled episodes.

The EPA did err in the proposed

rulemaking in listing ‘‘Hillside County’’

instead of Hillsdale County. This error

is corrected here. This error is not

sufficient, in the view of the EPA, to

warrant a revised proposed rulemaking.

The listing of the covered Counties and

the location of Hillsdale County should

have led a reviewer (as indeed it did the

commenter) of the proposed rulemaking

to conclude that the listing of ‘‘Hillside

County’’ was a typographical error and

that the EPA had intended to list

Hillsdale County.

III. Final Action

The comments received were

generally found to warrant no changes

from the proposed action on this NOX

exemption request with the following

exceptions: (1) EPA is not taking final

action to approve the NOX exemption

for transportation conformity

requirements of the Act for the ozone

nonattainment areas in the LMOS

domain classified as moderate and

above; (2) EPA is correcting the listing

of ‘‘Hillside County’’, Michigan to

Hillsdale County, Michigan; and (3) in

light of the modeling completed thus far

and considering the importance of the

OTAG process and attainment plan

modeling efforts, EPA grants this NOX

waiver on a contingent basis. As the

OTAG modeling results and control

recommendations are completed in

1996, this information will be

incorporated into attainment plans

being developed by the LADCO States.

When these attainment plans are

submitted to EPA in mid-1997, these

new modeling analyses will be reviewed
Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations 2437

to determine if the NOX waiver should

be continued, altered, or removed.

The final attainment plans will

supersede the initial modeling results

which are the basis of the NOX waiver

that EPA is granting in this notice. To

the extent the attainment plans include

NOX controls on certain major

stationary sources in the LMOS ozone

nonattainment areas, EPA will remove

the NOX waiver for those sources. To

the extent the plans achieve attainment

without additional NOX reductions from

certain sources, the NOX exemption

would continue for those sources. EPA’s

rulemaking action to reconsider the

initial NOX waiver may occur

simultaneously with rulemaking action

on the attainment plans. EPA reserves

the right to require NOX emission

controls in general or on a sourcespecific basis under section 110(a)(2)(D)

of the Act if future ozone modeling

demonstrates that such controls are

needed to achieve the ozone standard in

downwind areas.

This action will become effective on

February 26, 1996.

IV. Miscellaneous

A. Applicability to Future SIP Decisions

Nothing in this action should be

construed as permitting, allowing or

establishing a precedent for any future

request for revision to any state

implementation plan. The EPA shall

consider each request for revision to the

state implementation plan in light of

specific technical, economic, and

environmental factors and in relation to

relevant statutory and regulatory

requirements.

B. Executive Order 12866

This action has been classified as a

Table 3 action by the Regional

Administrator under the procedures

published in the Federal Register on

January 19, 1989 (54 FR 2214–2225), as

revised by an October 4, 1993

memorandum from Michael Shapiro,

Acting Assistant Administrator for Air

and Radiation. The Office of

Management and Budget has exempted

this regulatory action from Executive

Order 12866 review.

C. Regulatory Flexibility

Under the Regulatory Flexibility Act,

5 U.S.C. 600 et seq., EPA must prepare

a regulatory flexibility analysis

assessing the impact of any proposed or

final rule on small entities (5 U.S.C. 603

and 604). Alternatively, EPA may certify

that the rule will not have a significant

impact on a substantial number of small

entities. Small entities include small

businesses, small not-for-profit

enterprises, and government entities

with jurisdiction over populations of

less than 50,000.

This approval does not create any

new requirements. Therefore, I certify

that this action does not have a

significant impact on any small entities

affected. Moreover, due to the nature of

the Federal-State relationship under the

Act, preparation of the regulatory

flexibility analysis would constitute

Federal inquiry into the economic

reasonableness of the State action. The

Act forbids EPA to base its actions

concerning state implementation plans

on such grounds. Union Electric Co. v.

U.S.E.P.A., 427 U.S. 246, 256–66 (1976).

D. Unfunded Mandates

Under Sections 202, 203, and 205 of

the Unfunded Mandates Reform Act of

1995 (Unfunded Mandates Act), signed

into law on March 22, 1995, EPA must

assess whether various actions

undertaken in association with

proposed or final regulations include a

Federal mandate that may result in

estimated costs of $100 million or more

to the private sector, or to State, local,

or tribal governments in the aggregate.

EPA’s final action will relieve

requirements otherwise imposed under

the Clean Air Act and, hence does not

impose any federal intergovernmental

mandate, as defined in section 101 of

the Unfunded Mandates Act. This

action also will not impose a mandate

that may result in estimated costs of

$100 million or more to either State,

local, or tribal governments in the

aggregate, or to the private sector.

E. Petitions for Judicial Review

Under section 307(b)(1) of the Act,

petitions for judicial review of this

action must be filed in the United States

Court of Appeals for the appropriate

circuit by March 26, 1996. Filing a

petition for reconsideration by the

Administrator of this final rule does not

affect the finality of this rule for the

purpose of judicial rule, nor does it

extend the time within which a petition

for judicial review may be filed and

shall not postpone the effectiveness of

such rule or action. This action may not

be challenged later in proceedings to

enforce its requirements (see section

307(b)(2) of the Act.

List of Subjects in 40 CFR Part 52

Environmental protection, Air

pollution control, Oxides of nitrogen,

Incorporation by reference,

Intergovernmental relations, Ozone.

Dated: January 18, 1996.

Carol M. Browner,

Administrator.

Part 52, chapter I, title 40 of the Code

of Federal Regulations is amended as

follows:

PART 52—[AMENDED]

1. The authority citation for part 52

continues to read as follows:

Authority: 42 U.S.C. 7401–7671(q).

Subpart O—Illinois

2. Section 52.726 is amended by

adding paragraph (k) to read as follows:

§ 52.726 Control Strategy: Ozone

* * * * *

(k) Approval—EPA is approving the

section 182(f) oxides of nitrogen (NOX)

reasonably available control technology

(RACT), new source review (NSR),

vehicle inspection/maintenance (I/M),

and general conformity exemptions for

the Illinois portion of the Chicago-GaryLake County severe ozone

nonattainment area as requested by the

States of Illinois, Indiana, Michigan, and

Wisconsin in a July 13, 1994 submittal.

This approval does not cover the

exemption of NOX transportation

conformity requirements of section

176(c) for this area. Approval of these

exemptions is contingent on the results

of the final ozone attainment

demonstration expected to be submitted

in mid-1997. The approval will be

modified if the final attainment

demonstration demonstrates that NOX

emission controls are needed in the

nonattainment area to attain the ozone

standard in the Lake Michigan Ozone

Study modeling domain.

Subpart P—Indiana

2. Section 52.777 is amended by

adding paragraph (i) to read as follows:

§ 52.777 Control Strategy: Photochemical

oxidants (hydrocarbons).

* * * * *

(i) Approval—EPA is approving the

section 182(f) oxides of nitrogen (NOX)

reasonably available control technology

(RACT), new source review (NSR),

vehicle inspection/maintenance (I/M),

and general conformity exemptions for

the Indiana portion of the Chicago-GaryLake County severe ozone

nonattainment area as requested by the

States of Illinois, Indiana, Michigan, and

Wisconsin in a July 13, 1994 submittal.

This approval does not cover the

exemption of NOX transportation

conformity requirements of section

176(c) for this area. Approval of these

exemptions is contingent on the results
2438 Federal Register / Vol. 61, No. 18 / Friday, January 26, 1996 / Rules and Regulations

of the final ozone attainment

demonstration expected to be submitted

in mid-1997. The approval will be

modified if the final attainment

demonstration demonstrates that NOX

emission controls are needed in the

nonattainment area to attain the ozone

standard in the Lake Michigan Ozone

Study modeling domain.

* * * * *

Subpart X—Michigan

2. Section 52.1174 is amended by

adding paragraph (l) to read as follows:

§ 52.1174 Control Strategy: Ozone

* * * * *

(l) Approval—EPA is approving the

section 182(f) oxides of nitrogen (NOX)

reasonably available control technology

(RACT), new source review (NSR),

vehicle inspection/maintenance (I/M),

and general conformity exemptions for

the Grand Rapids (Kent and Ottawa

Counties) and Muskegon (Muskegon

County) moderate nonattainment areas

as requested by the States of Illinois,

Indiana, Michigan, and Wisconsin in a

July 13, 1994 submittal. This approval

also covers the exemption of NOX

transportation and general conformity

requirements of section 176(c) for the

Counties of Allegan, Barry, Bay, Berrien,

Branch, Calhoun, Cass, Clinton, Eaton,

Gratiot, Genesee, Hillsdale, Ingham,

Ionia, Jackson, Kalamazoo, Lenawee,

Midland, Montcalm, St. Joseph,

Saginaw, Shiawasse, and Van Buren.

Subpart YY—Wisconsin

2. Section 52.2585 is amended by

adding paragraph (i) to read as follows:

§ 52.2585 Control Strategy: Ozone.

* * * * *

(i) Approval—EPA is approving the

section 182(f) oxides of nitrogen (NOX)

reasonably available control technology

(RACT), new source review (NSR),

vehicle inspection/maintenance (I/M),

and general conformity exemptions for

the moderate and above ozone

nonattainment areas within Wisconsin

as requested by the States of Illinois,

Indiana, Michigan, and Wisconsin in a

July 13, 1994 submittal. This approval

also covers the exemption of

transportation and general conformity

requirements of section 176(c) for the

Door and Walworth marginal ozone

nonattainment areas. Approval of these

exemptions is contingent on the results

of the final ozone attainment

demonstration expected to be submitted

in mid-1997. The approval will be

modified if the final attainment

demonstration demonstrates that NOX

emission controls are needed in any of

the nonattainment areas to attain the

ozone standard in the Lake Michigan

Ozone Study modeling domain.

[FR Doc. 96–1413 Filed 1–25–96; 8:45 am]

BILLING CODE 6560–50–P

40 CFR Part 52

[LA–22–1–7184; FRL–5402–7]

Approval and Promulgation of Section

182(f) Exemption to the Nitrogen

Oxides (NOX) Control Requirements

for the Baton Rouge Ozone

Nonattainment Area; Louisiana

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Final rule.

SUMMARY: As requested by the State of

Louisiana in a petition submitted to the

EPA pursuant to section 182(f)(3) of the

Clean Air Act (CAA), the EPA is

granting an exemption from the

Reasonably Available Control

Technology (RACT) and New Source

Review (NSR) requirements for major

stationary sources of Oxides of Nitrogen

(NOX), from the vehicle Inspection/

Maintenance (I/M) NOX requirements,

and general conformity NOX

requirements for the Baton Rouge,

Louisiana serious ozone nonattainment

area. The EPA is approving the

exemption based on a demonstration

that additional NOX reductions would

not contribute to attainment of the

National Ambient Air Quality Standard

(NAAQS) for ozone in the

nonattainment area. The EPA is not

taking final action at this time on the

granting of an exemption from the

transportation conformity requirements

of the CAA for the Baton Rouge area.

The EPA is reserving the right to reverse

the approval of the exemption if

subsequent modeling data demonstrate

an ozone attainment benefit from NOX

emission controls.

EFFECTIVE DATE: This action is effective

as of January 18, 1996.

ADDRESSES: Copies of the exemption

request, public comments and EPA’s

responses are available for inspection at

the following address:

United States Environmental Protection

Agency, Region 6, Multimedia

Planning and Permitting Division,

1445 Ross Avenue, Suite 700, Dallas,

Texas 75202–2733.

Louisiana Department of Environmental

Quality, H.B. Garlock Building, 7290

Bluebonnet, Baton Rouge, Louisiana

70810.

FOR FURTHER INFORMATION CONTACT:

Ms. Jeanne McDaniels or Mr. Quang

Nguyen, Air Planning Section (6PD–L),

Multimedia Planning and Permitting

Division, U.S. EPA Region 6, 1445 Ross

Avenue, Dallas, Texas 75202–2733,

telephone (214) 665–7214.

SUPPLEMENTAL INFORMATION:

I. Background

On November 17, 1994, the State of

Louisiana submitted a petition to the

EPA requesting that the Baton Rouge

serious ozone nonattainment area be

exempted from requirements to

implement NOX controls pursuant to

section 182(f) of the CAA. The

exemption request is based on modeling

that demonstrates additional NOX

emission controls within the

nonattainment area will not contribute

to attainment of the ozone NAAQS

within the area. The Baton Rouge ozone

nonattainment area consists of the

following parishes: East Baton Rouge,

West Baton Rouge, Pointe Coupee,

Livingston, Iberville, and Ascension.

The State also provided supplemental

technical reports pertaining to the

modeling as part of the Baton Rouge

post-1996 rate-of-progress plan

submitted to the EPA on November 15,

1994. In addition, the State submitted

several follow-up letters to the petition

to: (1) revise a number of tables in the

November 17, 1994, petition, and (2)

broaden the scope of the original request

to also include exemptions under

section 182(f) for NOX NSR, general

conformity, and I/M NOX requirements.

On August 18, 1995, the EPA

published a rulemaking proposing

approval of the NOX exemption petition

for the six-parish ozone nonattainment

area (60 FR 43100). During the 30-day

public comment period, the EPA

received two letters commenting on the

proposal. Both expressed opposition to

the exemption. In addition to these

comments, in August 1994 three

environmental groups submitted joint

adverse comments on the proposed

approvals of NOX exemptions for the

Ohio and Michigan ozone

nonattainment areas. The comments

addressed the EPA’s general policy

regarding NOX exemptions. The

commenters requested that these

comments be addressed in all EPA

rulemakings dealing with section 182(f)

exemptions.

II. Public Comments

The following discussion summarizes

the comments received regarding the

State’s petition and/or the EPA’s

proposed rulemaking and presents the

EPA’s responses to these comments.

Comment: Commenters argued that

NOX exemptions are provided for in two

separate parts of the CAA, in sections