Regional Haze Regulations

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 51

[FRL-6353-4]

RIN 2060-AF32

[Docket No A-95-38]

Regional Haze Regulations

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: Section 169A of the Clean Air Act (CAA) sets forth a national

goal for visibility which is the ``prevention of any future, and the

remedying of any existing, impairment of visibility in Class I areas

which impairment results from manmade air pollution.'' There are 156

Class I areas across the country, including many well-known national

parks and wilderness areas, such as the Grand Canyon, Great Smokies,

Shenandoah, Yellowstone, Yosemite, the Everglades, and the Boundary

Waters. Regional haze is visibility impairment caused by the cumulative

air pollutant emissions from numerous sources over a wide geographic

area. The EPA promulgated regulations in 1980 to address visibility

impairment that is ``reasonably attributable'' to one or a small group

of sources, but EPA deferred action on regional haze regulations until

monitoring, modeling, and scientific knowledge about the relationship

between pollutants and visibility effects improved. In 1993, the

National Academy of Sciences (NAS) concluded that ``current scientific

knowledge is adequate and control technologies are available for taking

regulatory action to improve and protect visibility.''

On July 31, 1997 (62 FR 41138), EPA published proposed amendments

to the 1980 regulations to set forth a program to address regional haze

visibility impairment. The EPA also published a notice of availability

of additional information on the proposed regional haze regulation on

September 3, 1998. This notice took comment specifically on new

implementation plan timelines set forth in the Transportation Equity

Act for the 21st Century, Public Law 105-178, and on a proposal from

the Western Governors' Association (WGA) for addressing the

recommendations of the Grand Canyon Visibility Transport Commission

(GCVTC) in the final rule. The EPA received more than 1300 comments

overall on the proposal and notice of availability.

Today's final rule calls for States to establish goals and emission

reduction strategies for improving visibility in all 156 mandatory

Class I national parks and wilderness areas. Specific provisions are

included in the rule allowing nine western States to implement the

recommendations of the GCVTC within the framework of the national

regional haze program. In addition, EPA encourages States to work

together in regional partnerships to develop and implement multistate

strategies to reduce emissions of visibility-impairing fine particle

pollution.

DATES: The regulatory amendments announced herein take effect on August

30, 1999.

ADDRESSES: Docket. The public docket for this action is available for

public inspection and copying between 8:00 a.m. and 5:30 p.m., Monday

through Friday excluding legal holidays, at the Air and Radiation

Docket and Information Center (6102), Attention: Docket A-95-38, Room

M-1500, 401 M Street, SW, Washington, DC 20460, phone 202-260-7548, fax

202-260-4400, email: A-and-R-D[email protected]. A reasonable fee

for copying may be charged. The regional haze regulations are subject

to the rulemaking procedures under section 307(d) of the CAA. The

documents relied on to develop the regional haze regulations have been

placed in the docket.

FOR FURTHER INFORMATION CONTACT: For general questions regarding this

notice, contact Richard Damberg, U.S. EPA, MD-15, Research Triangle

Park, NC 27711, telephone (919) 541-5592, email: [email protected].

SUPPLEMENTARY INFORMATION:

Electronic Availability

The official record for this rulemaking, as well as the public

version, has been established under docket number A-95-38 (including

comments and data submitted electronically as described below). A

public version of this record, including printed, paper versions of

electronic comments, which does not include any information claimed as

Confidential Business Information, is available for inspection from

8:00 a.m. to 5:30 p.m., Monday through Friday, excluding legal

holidays. The official rulemaking record is located at the address in

ADDRESSES at the beginning of this document. World Wide Web sites have

been developed for overview information on visibility issues and

related programs. These web sites can be accessed from Uniform Resource

Locator (URL):

http://www.epa.gov/airlinks/.

Table of Contents

I. Overview of Today's Final Rule

II. Background Information on the Regional Haze Program

A. Regional Haze

B. How Today's Final Rule Responds to the CAA

C. The 1980 Visibility Regulation--Commitment to a Regional Haze

Program

D. Sources of Scientific Information and Policy Recommendations

on Regional Haze

E. Relationship to Secondary NAAQS for PM

F. Regional Planning and Integration with Programs to Implement

the NAAQS for Ozone and Particulate Matter

III. Discussion of National Program Requirements and Response to

Comments

A. Scope of Rule--Extending Coverage to All States

B. Timetable for Submitting the First Regional Haze SIP

C. Tracking Deciviews and Emissions Reductions

D. Regional Haze Implementation Plan Principles

E. Determination of ``Baseline,'' ``Natural'' and ``Current''

Visibility

F. Reasonable Progress Goals

G. Long-Term Strategy

H. Best Available Retrofit Technology(BART)

I. Monitoring Strategy and Other Implementation Plan

Requirements

J. Periodic SIP Revisions and 5-Year Progress Reports

K. Coordination with Federal Land Managers

IV. Treatment of the GCVTC Recommendations

A. Background

B. General Requirements of Section 51.309

C. Elements of the GCVTC-Based State and Tribal Implementation

Plans

D. Requirements for States Electing Not To Follow All Provisions

of the Section 51.309(e)

E. Annex to the GCVTC Report

F. Additional Class I Areas

V. Implementation of the Regional Haze Program in Indian Country

A. Background on Tribal Air Quality Programs

B. Issues Related to the Regional Haze Program in Indian Country

VI. Miscellaneous Technical Amendments to the Existing Rule

VII. Administrative Requirements

A. Regulatory Planning and Review by the Office of Management

and Budget (OMB) (Executive Order 12866)

B. Regulatory Flexibility Act

C. Paperwork Reduction Act--Impact on Reporting Requirements

D. Unfunded Mandates Reform Act

E. Environmental Justice--Executive Order 12898

F. Congressional Review Act

G. Protection of Children From Environmental Health Risks and

Safety Risks--Executive Order 13045

H. Enhancing the Intergovernmental Partnership-- Executive Order

12875

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I. Executive Order 13084: Consultation and Coordination with

Indian Tribal Governments

J. National Technology Transfer and Advancement Act

I. Overview of Today's Final Rule

This preamble provides the details and rationale for the final

regional haze rule. Unit II includes background information on regional

haze and on the legal and scientific basis for today's action. Unit III

describes the provisions of the national requirements for regional haze

and includes a discussion of the comments received on the July 1997

proposal. Unit IV discusses specific regional provisions for 16 western

Class I areas that were the subject of a 1996 report by the GCVTC. Unit

V is a discussion of issues related to implementation of the rule by

Indian tribes. Unit VI summarizes several technical amendments to

existing visibility regulations in order to coordinate those

requirements with the requirements of today's final rule. Unit VII

discusses how today's final rulemaking is in compliance with the

requirements of various executive orders and statutes.

II. Background Information on the Regional Haze Program

A. Regional Haze

Regional haze is visibility impairment that is produced by a

multitude of sources and activities which emit fine particles and their

precursors and which are located across a broad geographic

area.1 Twenty years ago, when initially adopting the

visibility protection provisions of the CAA, Congress specifically

recognized that the ``visibility problem is caused primarily by

emission into the atmosphere of SO2, oxides of nitrogen, and

particulate matter, especially fine particulate matter, from

inadequate[ly] controlled sources.'' 2 The fine particulate

matter (PM) (e.g., sulfates, nitrates, organic carbon, elemental

carbon, and soil dust) that impairs visibility by scattering and

absorbing light can cause serious health effects and mortality in

humans, and contribute to environmental effects such as acid deposition

and eutrophication. Data from the existing visibility monitoring

network show that visibility impairment caused by air pollution occurs

virtually all the time at most national park and wilderness area

monitoring stations.3 Average visual range in many Class I

areas 4 in the Western United States is 100-150 kilometers

(13.6-9.6 deciviews), 5 or about one-half to two-thirds of

the visual range that would exist without manmade air pollution. In

most of the east, the average visual range is less than 30 kilometers

(25 deciviews or more), or about one-fifth of the visual range that

would exist under estimated natural conditions. The role of regional

transport of fine particles in contributing to elevated PM levels and

regional haze impairment has been well documented by many researchers

6 and recognized as a significant issue by policymakers from

Federal, State and local agencies, industry and environmental

organizations.

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\1\ U.S. EPA. Air Quality Criteria for Particulate Matter.

Office of Research and Development, National Center for

Environmental Assessment. EPA/600/P-95/001bF. Research Triangle

Park, NC. 1996.

\2\ H.R. Rep. No. 95-294 at 204 (1977).

\3\ National Park Service. Air Quality in the National Parks: A

Summary of Findings from the National Park Service Air Quality

Research and Monitoring Program. Natural Resources Report 88-1.

Denver, CO, July 1988.

\4\ Areas designated as mandatory Class I Federal areas are

those national parks exceeding 6000 acres, wilderness areas and

national memorial parks exceeding 5000 areas, and all international

parks which were in existence on August 7, 1977. Visibility has been

identified as an important value in 156 of these areas. See 40 CFR

part 81, subpart D. The extent of a Class I area includes subsequent

changes in boundaries, such as park expansions. (CAA section

162(a)). States and tribes may designate additional areas as Class

I, but the requirements of the visibility program under section 169A

of the CAA apply only to ``mandatory Class I Federal areas,'' and

they do not directly address any additional areas.

\5\ ``Deciview'' is a visibility metric discussed further in

unit III.C. of today's notice, and defined in section 51.301(bb) of

the rule. Higher deciview values indicate greater levels of

visibility impairment.

\6\ See National Acid Precipitation Assessment Program. Acid

Deposition: State of Science and Technology. Report 24, Visibility:

Existing and Historical Conditions--Causes and Effects, Table 24-6.

Washington, DC 1991. See also U.S. EPA. Air Quality Criteria for

Particulate Matter. Office of Research and Development, National

Center for Environmental Assessment. EPA/600/P-95/001bF. Research

Triangle Park, NC. 1996.

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B. How Today's Final Rule Responds to the CAA

The visibility protection program under sections 169A, 169B, and

110(a)(2)(J) of the CAA is designed to protect Class I areas

7 from impairment due to manmade air pollution. Congress

adopted the visibility provisions in the CAA to protect visibility in

these ``areas of great scenic importance.'' 8 The current

regulatory program addresses visibility impairment in these areas that

is ``reasonably attributable'' 9 to a specific source or

small group of sources. In adopting section 169A, the core visibility

provisions adopted in the 1977 CAA Amendments, Congress also expressed

its concern with visibility problems caused by pollutants that

``emanate from a variety of sources.'' It noted the problem of

``hazes'' from ``regionally distributed sources,'' 10 and

concluded that additional provisions were needed to remedy ``the

growing visibility problem.'' The purpose of today's final rule is to

revise the existing visibility regulations 11 in order to

integrate provisions addressing regional haze impairment. Today's final

rule establishes a comprehensive visibility protection program for

Class I areas. Figure 1 is a map indicating the locations of the Class

I areas.

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\7\ For the purposes of this preamble, the term ``Class I area''

will be used to describe the 156 mandatory Class I Federal areas

identified in section 51.301(o) and in part 81, subpart D of this

title.

\8\ H.R. Rep. No. 294, 95th Cong. 1st Sess. at 205 (1977).

\9\ ``Reasonably attributable'' visibility impairment, as

defined in section 51.301(s), means ``attributable by visual

observation or any other technique the State deems appropriate.'' It

includes impacts to Class I areas caused by plumes or layered hazes

from a single source or small group of sources.

\10\ H.R. Rep. No. 95-294 at 204 (1977).

\11\ 45 FR 80084 (December 2, 1980) and section 51.300-307.

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C. The 1980 Visibility Regulation--Commitment to a Regional Haze

Program

Section 169A of the CAA, established in the 1977 Amendments, sets

forth a national visibility goal that calls for ``the prevention of any

future, and the remedying of any existing, impairment of visibility in

Class I areas which impairment results from manmade air pollution.''

The EPA's initial visibility regulations, developed in 1980, address

visibility impairment that is ``reasonably attributable'' to a single

source or small group of sources. Under the 1980 rules, the 35 States

and 1 territory containing Class I areas 12 are required to:

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\12\ The States and one territory having at least one Class I

area are listed in section 51.300(b)(2). These States and one

territory are as follows: Alabama, Alaska, Arizona, Arkansas,

California, Colorado, Florida, Georgia, Hawaii, Idaho, Kentucky,

Louisiana, Maine, Michigan, Minnesota, Missouri, Montana, Nevada,

New Hampshire, New Jersey, New Mexico, North Carolina, North Dakota,

Oklahoma, Oregon, South Carolina, South Dakota, Tennessee, Texas,

Utah, Vermont, Virginia, Virgin Islands, Washington, West Virginia,

and Wyoming. For a specific list of Class I areas located in each

state or territory, see 40 CFR 81.401-437.

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(1) Revise their SIPs to assure reasonable progress toward the

national visibility goal;

(2) Determine which existing stationary facilities should install

the best available retrofit technology (BART) for controlling

pollutants which impair visibility;

(3) Develop, adopt, implement, and evaluate long-term strategies

for making reasonable progress toward remedying any existing and

preventing any future impairment in the Class I areas;

(4) Adopt certain measures to assess potential visibility impacts

due to new or modified major stationary sources, including measures to

notify Federal land managers (FLMs) of proposed new source permit

applications, and to consider visibility analyses conducted by FLMs in

their new source permitting decisions; and

(5) Conduct visibility monitoring in Class I areas.

The 1980 rules addressing ``reasonably attributable'' visibility

impairment were designed to be the first phase in EPA's overall program

to protect visibility. The EPA explicitly deferred national rules

addressing regional haze impairment until some future date:

* * * when improvement in monitoring techniques provides more data

on source-specific levels of visibility impairment, regional scale

models become refined, and our scientific knowledge about the

relationships between emitted air pollutants and visibility

impairment improves.13

\13\ 45 FR 80086.

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The EPA believes that the technical tools and our scientific

understanding of visibility impairment are now sufficiently refined to

move forward with a national program addressing regional haze in Class

I areas. The EPA's position is supported by the NAS 1993 report,

Protecting Visibility in National Parks and Wilderness Areas. One of

the principal conclusions of this report is that ``current scientific

knowledge is adequate and control technologies are available for taking

regulatory action to improve and protect visibility.'' 14

Section II.D. describes a number of other studies and information now

available which provide the technical basis to move forward with a

regional haze program.

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\14\ National Research Council Committee on Haze in National

Parks and Wilderness Areas, Protecting Visibility in National Parks

and Wilderness Areas, National Academy Press, 1993, p. 11.

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In addition, EPA finds the visibility protection provisions of the

CAA to be quite broad. Although EPA is addressing visibility protection

in phases, the national visibility goal in section 169A calls for

addressing visibility impairment generally, including regional

haze.15

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\15\ State of Maine v. Thomas, 874 F.2d 883, 885 (1st Cir. 1989)

(``EPA's mandate to control the vexing problem of regional haze

emanates directly from the CAA, which `declares as a national goal

the prevention of any future, and the remedying of any existing,

impairment of visibility in Class I areas which impairment results

from manmade air pollution.' '') (citation omitted).

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Further, Congress added section 169B as part of the 1990 Amendments

to the CAA to focus attention on regional haze issues; it calls for EPA

to issue regional haze rules within 18 months of receipt of the final

report from the GCVTC. In addition, section 169B includes provisions

for EPA to conduct visibility research with the National Park Service

and other Federal agencies, to develop an interim findings report on

the visibility research,16 to develop a Report to Congress

on expected visibility improvements due to implementation of other air

pollution programs,17 and to provide periodic reports to

Congress on trends in visibility improvements. Section 169B also

provides the authority to the Administrator to establish visibility

transport commissions in response to a petition from two or more

States, or on her and/or his own motion. To date, EPA has not received

any petitions from groups of States requesting formation of a

visibility transport commission.

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\16\ U.S. EPA, Interim Findings on the Status of Visibility

Research, Office of Research and Development, EPA/600/R-95/021,

February 1995. See also 60 FR 8659 notice announcing the report

availability and how to obtain copies (Feb. 15, 1995.

\17\ U.S. EPA, Effects of the 1990 CAA Amendments on Visibility

in Class I Areas: An EPA Report to Congress, October 1993 (EPA-452/

R-93-014).

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Section 169B(f) called for EPA to establish a visibility transport

commission for the region affecting visibility of the Grand Canyon

National Park. The purpose of this commission was to assess scientific

and technical information pertaining to adverse impacts on visibility

at the Park from existing emissions and projected growth in emissions.

The statute specifically called for a report to EPA recommending

measures to remedy such impacts and to address long-term strategies for

addressing regional haze.18 In 1991, EPA established the

GCVTC,19 and the GCVTC issued its final report in June

1996.20 The recommendations of the GCVTC and their

incorporation as potential SIP requirements into the final rule, are

discussed in greater detail in unit IV of the preamble.

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\18\ CAA section 169B(d)(2)(C).

\19\ 56 FR 57522, November 12, 1991.

\20\ Grand Canyon Visibility Transport Commission,

Recommendations for Improving Western Vistas, Report to the U.S.

EPA, June 10, 1996 (hereafter referred to as ``GCVTC Report'').

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Finally, section 169B(e) calls for the Administrator to consider

past research and the recommendations of visibility transport

commissions in carrying out the ``regulatory responsibilities under

section 169A, including criteria for measuring `reasonable progress'

toward the national goal.'' 21 The EPA is required by the

CAA to meet these regulatory responsibilities within 18 months of

receiving the GCVTC report. Today's final rule fulfills EPA's

responsibility under section 169A, pending since 1980, to put in place

a national regulatory program that addresses both reasonably

attributable and regional haze visibility impairment. Today's action is

also EPA's response to the GCVTC report as anticipated by section 169B.

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\21\ CAA section 169B(e)(1).

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D. Sources of Scientific Information and Policy Recommendations on

Regional Haze

In developing today's revisions to the visibility regulations, EPA

has taken into account a significant body of scientific information and

policy recommendations on visibility issues that have been developed

over more than 20 years. This unit highlights key sources of

information upon which the final regional haze rule is based.

For many years, visibility impairment has been considered the

``best understood and most easily measured

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effect of air pollution.'' 22 Visibility degradation has

also been recognized as an indicator of multiple human-health effects

and environmental effects resulting from air pollution all over the

world.23 Visibility conditions have been monitored and

evaluated for many years, using airport visibility data collected from

the 1940's to the present.24

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\22\ Council on Environmental Quality, Visibility Protection for

Class I Areas: The Technical Basis, Washington, DC, 1978.

\23\ National Research Council, NAS Committee on Haze in

National Parks and Wilderness Areas, Protecting Visibility in

National Parks and Wilderness Areas, National Academy Press, 1993,

p. 23.

\24\ National Acid Precipitation Assessment Program (NAPAP),

Acid Deposition: State of Science and Technology. Report 24,

Visibility: Existing and Historical Conditions--Causes and Effects,

Washington, DC, 1991.

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In October 1979, EPA published a Report to Congress describing the

state of the science on visibility.25 The report, required

under section 169A(a)(3), described available methods for visibility

monitoring, modeling, and assessment of strategies to make progress

toward the national goal. This report was developed in advance of the

1980 visibility regulations. As noted above, EPA deferred action on

regional haze until monitoring techniques, modeling capabilities, and

the understanding of the pollutants affecting visibility were improved.

In 1986, the IMPROVE (Interagency Monitoring of Protected Visual

Environments) visibility monitoring program was initiated in 30 Class I

areas. The IMPROVE program has been coordinated through a cooperative,

multiagency approach with participation by EPA, the FLMs, and States.

Through the IMPROVE program, significant progress has been made in

understanding the effect of various pollutants on current visibility

conditions and trends, in developing well-accepted monitoring

protocols, and in developing a sound approach for calculating light

extinction values from aerosol and humidity data. The IMPROVE program

has issued two major reviews of the monitoring data collected to

date,26 and numerous technical papers have been developed

using data collected by the network.

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\25\ U.S. EPA, Protecting Visibility: An EPA Report to Congress;

Office of Air Quality Planning and Standards, EPA-450/5-79-008,

October 1979.

\26\ Sisler, J. et al., Spatial and Seasonal Patters and Long-

Term Variability of the Chemical Composition of the Haze in the

U.S.: An Analysis of Data from the IMPROVE Network, Fort Collins,

CO, Cooperative Institute for Research in the Atmosphere, Colorado

State University, 1996. See also Sisler, J., et al., Spatial and

Temporal Patters and the Chemical Composition of the Haze in the

United States: An Analysis of Data From the IMPROVE Network, 1988-

1991, Fort Callins, CO, 1993.

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In addition, in 1996 EPA began to include a chapter on visibility

trends, based on data collected throughout the IMPROVE network, in the

National Air Quality and Emissions Trends Report in 1996.27

Data from 1988 to the present are analyzed for the best 20 percent,

middle 20 percent, and worst 20 percent days of the annual

distribution, and aggregated for eastern and western sites. Annual

summary data are also presented for each individual site in an

appendix.

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\27\ U.S. EPA, National Air Quality and Emissions Trends Report,

1996, Office of Air Quality Planning and Standards, EPA 454/R-97-

013, January 1998. See also U.S. EPA, National Air Quality and

Emissions Trends Report, 1997, Office of Air Quality Planning and

Standards, EPA 454/R-98-016, January 1999.

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Visibility research continued throughout the 1980's and is

documented in many published articles and the proceedings of three

major visibility conferences.28 In addition, the NAPAP

completed a comprehensive review of the state of the science of

visibility in 1991.29 This peer-reviewed report reached a

number of important conclusions, including: (1) Light scattering is

dominated by fine particles; (2) sulfates are the dominant source of

light extinction in the east, and one of several major sources of

extinction in the west; (3) rural visibility varies significantly

between the east and west; (4) average natural visibility conditions

are 150 kilometers visual range (9.6 deciviews) in the east and 230

kilometers visual range (5.3 deciviews) in the west; and (5) haze

trends in the eastern United States have been dominated by sulfur

emission trends since the late 1940's.

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\28\ Atmospheric Environment, Proceedings of EPA Symposium on

Plumes and Visibility--Measurements and Model Components, November

1980, Atmos. Environ., 15:1785-2646. See also Bhardwaja, P.J., ed.,

Visibility Protection: Research and Policy Aspects. Transactions of

APCA Specialty Conference, September 1986, Grand Tetons National

Park, WY. Air Pollution Control Assoc., Pittsburgh, PA, 1987. See

also Mathai, C.V., ed., Visibility and Fine Particles. Transactions

of AWMA specialty conference, October 1989, Estes Park, CO. Air and

Waste Management Assoc., Pittsburgh, PA, 1990.

\29\ National Acid Precipitation Assessment Program (NAPAP),

Acid Deposition: State of Science and Technology, Report 24,

Visibility: Existing and Historical Conditions--Causes and Effects,

Washington, DC, 1991.

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The NAS formed a Committee on Haze in National Parks and Wilderness

Areas in 1990 to address a number of regional haze-related issues,

including methods for determining anthropogenic source contributions to

haze and methods for considering alternative source control measures.

The 1993 report by this Committee contributed significantly to the

state of the science regarding regional haze visibility

impairment.30 The Committee issued several important

conclusions in the report, including: (1) Current scientific knowledge

is adequate and control technologies are available for taking

regulatory action to address regional haze; (2) progress toward the

national goal will require regional programs that operate over large

geographic areas and limit emissions of pollutants that can cause

regional haze; (3) a program to address regional haze visibility

impairment that focuses solely on determining the contributions of

individual emission sources to such visibility impairment is likely to

fail, and instead, strategies should be adopted to consider

simultaneously the effect of many sources on a regional basis; (4)

visibility impairment can be attributed to emission sources on a

regional scale through the use of several kinds of models; (5)

visibility and control policies might need to be different in the west

than the east; (6) efforts to improve visibility within Class I areas

will benefit visibility outside these areas and could help alleviate

other types of air quality problems as well; (7) achieving the national

visibility goal will require a substantial, long-term program; and (8)

continued progress toward this goal will require a greater commitment

toward atmospheric research, monitoring, and emissions control research

and development.

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\30\ National Research Council, NAS Committee on Haze in

National Parks and Wilderness Areas, Protecting Visibility in

National Parks and Wilderness Areas, National Academy Press,

Washington, DC, 1993.

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Also in 1993, EPA developed its Report to Congress on the projected

effects on visibility in Class I areas due to implementation of the

1990 CAA Amendments. 31 The report concluded that conditions

on the worst visibility days are expected to improve by approximately 3

deciviews by 2010 across the most impaired portions of the Eastern

United States. Most of this improvement is expected in the 1995-2005

timeframe due to sulfur dioxide reductions under the acid rain program.

In the Southwestern United States, the visibility change was predicted

to be less than 1 deciview in most Class I areas except San Gorgonio

Wilderness (which is located downwind of Los Angeles), for which a 1-2

deciview improvement is expected.

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\31\ U.S. EPA, Effects of the 1990 Clean Air Act Amendments on

Visibility in Class I Areas: An EPA Report to Congress, Office of

Air Quality Planning and Standards, EPA-452/R-93-014, October 1993.

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As required by section 169B(a)(2) of the CAA, EPA issued a report

in 1995 on interim findings on the status of visibility research

completed since 1990.32 This report reviewed four major

visibility related reports published since 1990,33 provided

citations of published research papers, and summarized research under

way by the GCVTC, four Federal agencies, and the Electric Power

Research Institute. As noted above, the GCVTC issued a report in June

1996 containing recommendations for protecting visibility at 16 Class I

areas on the Colorado Plateau. Based on EPA's discretionary authority

under section 169B(c), it expanded the scope of the GCVTC:

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\32\ U.S. EPA, Interim Findings on the Status of Visibility

Research, Office of Research and Development, EPA/600/R-95/021,

February 1995.

\33\ These repdorts have already been mentioned in this section:

the 1993 NAS report, the 1993 IMPROVE report (Sisler et al.), the

1993 EPA Report to Congress, and the 1991 NAPAP Report to Congress.

* * * to include additional Class I areas in the vicinity of the

Grand Canyon National Park---what is sometimes referred to as the

``Golden Circle'' of parks and wilderness areas. This includes most

of the national parks and national wilderness areas of the Colorado

Plateau.34

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\34\ 56 FR 57523

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The GCVTC was charged with assessing information about visibility

impacts in the region and making policy recommendations to EPA to

address such impacts. The CAA called for the GCVTC to assess studies

conducted under section 169B as well as other available information

``pertaining to adverse impacts on visibility from potential or

projected growth in emissions for sources located in the * * *

Region,'' and to issue a report to EPA recommending what measures, if

any, should be taken to protect visibility. 35 The CAA

specifically provided for the GCVTC's report to address the following

measures: (1) The establishment of clean air corridors, in which

additional restrictions on increases in emissions may be appropriate to

protect visibility in affected Class I areas; (2) the imposition of

additional new source review requirements in clean air corridors;

36 and (3) the promulgation of regulations addressing

regional haze.

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\35\ CAA Section 169B(d).

\36\ A clean air corridor is defined as a region that generally

brings clear air to a receptor region, such as the Class I areas of

the Golden Circle.

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In unit IV of the proposal, EPA discusses the major recommendations

of the GCVTC. The GCVTC's recommendations have components that

contemplate implementation through a combination of actions by EPA,

other Federal agencies, States and tribes in the region, and voluntary

measures on the part of public and private entities throughout the

region. The GCVTC's recommendations also distinguish between

recommended actions and policy or strategy options for consideration.

Unit IV addresses how EPA took these recommendations, as well as the

body of technical information developed by the GCVTC, into account in

developing the final rule.

Response to comments. Some commenters on the regional haze proposal

suggested that EPA had not provided an adequate scientific or legal

justification for developing a regional haze program. The commenters

asserted that the science of regional haze is not understood well

enough to develop regulations at this time. In addition, some

commenters claimed that EPA has not provided adequate technical

guidance for implementation of the rule, and that providing such

guidance is a legal prerequisite to promulgating a regional haze rule.

The EPA does not agree with these claims.

First, EPA believes it has relied upon a substantial amount of

scientific evidence to support development of the regional haze

program. Many of the important studies, reports, and other scientific

and technical information on which the regional haze rule is based are

referenced earlier in this section. In particular, the NAS Committee on

Haze in National Parks and Wilderness Areas concluded that ``Current

scientific knowledge is adequate and control technologies are available

for taking regulatory action to improve and protect visibility.''

37 Thus, EPA believes that its decision to move forward with

promulgation of the regional haze program is reasonable, particularly

in light of the fact that the Agency's obligation to address regional

haze originated more than 20 years ago with passage of the 1977 CAA

Amendments.

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\37\ National Research Council, NAS Committee on Haze in

National Parks and Wilderness Areas, Protecting Visibility in

National Parks and Wilderness Areas, National Academy Press,

Washington, DC, 1993, p. 11.

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Second, as discussed in the response to comments, today's final

rule provides the States with the necessary guidelines to implement a

regional haze program. The EPA believes that the supposition that all

technical guidance associated with a program be developed before a rule

can be promulgated is unfounded. The EPA recognizes the importance of

timely implementation guidance and is committed to providing such

guidance, as appropriate, for the regional haze program.

The EPA does not interpret sections 169A and 169B as requiring all

technical guidance to be issued by the Agency before the rule is

finalized. The EPA is committed to working closely with the States and

other interested parties in developing effective guidance documents

within a reasonable period of time after promulgation of the final

regional haze rule.

E. Relationship to Secondary NAAQS for PM

Today's final rule is an important element in EPA's overall

approach to protecting visibility under the CAA. In July 1997, EPA

established national secondary ambient air quality standards (NAAQS)

for particles with an aerodynamic diameter less than or equal to a

nominal 2.5 micrometers (PM2.5) as part of its final

decision on revision of the existing NAAQS for particulate matter under

section 109(d) of the CAA.38 The secondary standards were

based on EPA's determination that the levels selected were ``requisite

to protect the public welfare'' against visibility impairment on a

nationally uniform basis as provided in section 109(b). Consistent with

the purposes of section 169A, however, EPA recognized that such

nationally uniform standards would not eliminate all visibility

impairment in all parts of the country.39 The visibility

impacts remaining in Class I areas are addressed by today's final rule.

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\38\ 62 FR 38652 (July 18, 1997).

\39\ See section 160(1); H.R. Rep. No. 95-294 at 205 (1977).

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Today's final rule has additional benefits, as EPA expects the

regional strategies implemented as part of the regional haze program to

improve visibility outside of Class I areas as well. Thus, the regional

haze program should contribute to the improvement of local visibility

impacts outside of Class I areas that may persist after attainment of

the secondary standards.

F. Regional Planning and Integration With Programs to Implement the

NAAQS for Ozone and Particulate Matter

The regional haze program is being promulgated in a manner that

facilitates integration of emission management strategies for regional

haze with the implementation of programs for new NAAQS for ozone and

PM. This is being done because of the existing scientific evidence that

these air quality problems have common precursor pollutants, emission

sources, atmospheric processes, spatial scales for transport, and

geographic areas of concern.

[[Page 35720]]

Because of the key role of regional pollutant transport in contributing

to haze at Class I areas, most of which are in remote locations, the

regional haze program recognizes the value of multistate coordination

for regional haze program planning and implementation. Consistent with

the recommendations of the Clean Air Act Advisory Committee,

Subcommittee on Ozone, Particulate Matter, and Regional Haze

Implementation Programs,40 EPA strongly encourages States to

undertake multistate regional planning efforts addressing regional haze

in a way that coordinates technical analyses and strategy development

with the NAAQS to the maximum extent possible. Examples of ongoing

coordination among States to address visibility issues include the

Western Regional Air Partnership (WRAP) and the Southern Appalachian

Mountain Initiative.

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\40\ Subcommittee for Ozone, Particulate Matter, and Regional

Haze Implementation Programs, Final Report on Subcommittee

Discussions, May 1998.

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The EPA believes that States (and tribes, at their discretion), in

partnership with other interested stakeholders, should consider

conducting future regional air quality planning efforts to address the

implementation of the ozone and PM NAAQS and regional haze program. We

encourage States to continue to work together to establish common

protocols and approaches for emissions inventory development, emissions

tracking, application of regional models, and development of effective

emission reduction strategies.

The EPA plans to participate early and actively in regional

planning efforts. The EPA recognizes that we must provide early input

on issues and to make our views known as issues arise. The EPA has a

responsibility to independently review the adequacy of implementation

plans in the public rulemaking process and to consider all public

comments received on a plan in determining if it meets applicable

requirements. However, it is equally important that EPA be open in

letting participants know of our views and concerns throughout the

process.

The EPA will soon issue final guidance on such regional planning

efforts for the purposes of implementing the ozone, particulate matter,

and regional haze implementation programs.41 Also, as a part

of EPA's 1999 fiscal year budget, Congress provided $4 million dollars

to support regional planning activities. EPA is currently involved with

the States in a process to define the appropriate size and composition

of regional planning bodies. The final planning guidance will provide a

discussion of several important issues related to regional planning

efforts. These issues include:

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\41\ See the November 17, 1998 draft of Implementation Guidance

for the Ozone and Particulate Matter NAAQS and Regional Haze

Program. EPA's internet site for an electronic version of this

guidance: http://www.epa.gov/ttn/oarpg/tlpgm.html.

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Taking credit for emissions reductions in other States;

Important principles for future regional planning efforts;

The technical assessment process; and

The strategy development process.

Some important principles discussed in the guidance for conducting

regional planning efforts include the following points.

Regional planning efforts should be a product of State

(and, at the discretion of any tribe, tribal) leadership and, thus,

should be led by States (and tribes), not EPA. Representatives should

have the authority to speak for their organizations.

States (and tribes at their discretion) should be prepared

to make strong, early commitments to implementing the outcome of the

regional process to ensure that SIP submittal dates are met.

Participants in regional planning efforts should set up a

work plan to carry out their work. The work plan should contain clearly

stated products of the process, dates for completion of those products

and mechanisms for funding the needed analyses.

The technical assessment process should include steps for

problem definition, development of emissions inventories, and

development of tools to evaluate strategy alternatives.

In the strategy development process, participants should

strive to develop a consensus about (1) the set of regional emissions

reductions strategies needed to attain the NAAQS or make ``reasonable

progress'' toward the national visibility goal in Class I areas, and

(2) the degree to which each State and relevant source category should

be required to reduce emissions to implement the recommended

strategies.

III. Discussion of National Program Requirements and Response to

Comments

Scope of Rule--Extending Coverage to All States

Proposed rule. In the regional haze proposal, EPA proposed to amend

section 51.300(b)(3) to extend coverage to all States (excluding

certain territories) for the purpose of addressing regional haze

visibility impairment. This approach differed from the 1980 visibility

regulations for ``reasonably attributable'' impairment, which required

the 35 States and the Virgin Islands containing Class I areas to submit

SIP revisions and to revise them periodically to assure reasonable

progress toward the national visibility goal. Thus, under the proposal,

the following additional States and the District of Columbia would be

required to submit visibility SIPs: Nebraska, Kansas, Iowa, Wisconsin,

Illinois, Indiana, Ohio, Mississippi, New York, Pennsylvania,

Massachusetts, Rhode Island, Connecticut, and Maryland. The territories

of Puerto Rico, Guam, American Samoa, and the Northern Mariana Islands

were not included because their distance from any Class I area

significantly exceed the distance that their emissions could be

expected to be transported in order to contribute to visibility

impairment in any Class I area. However, Hawaii, Alaska, and the Virgin

Islands would be subject to the regional haze provisions because of the

potential for emissions from sources within their borders to contribute

to regional haze impairment in Class I areas also located within their

own jurisdiction.

In the proposal, EPA also recommended that all States initially

participate in regional planning efforts to more precisely characterize

which States are contributing to visibility impairment in other States,

as well as the magnitude of such contributions. States could then

develop strategies for making reasonable progress in Class I areas

throughout the region. The EPA noted that as a result of this process,

all States may not have to adopt control strategies. At the same time,

EPA cited the 1993 NAS report, which observed that the requirement for

a State to revise its implementation plan if it ``may reasonably be

anticipated'' to contribute to visibility impairment indicates that

Congress intended that ``the philosophy of precautionary action should

apply to visibility protection as it applies to other areas [such as

the NAAQS].'' Thus, EPA proposed that, at a minimum, all States should

be required to develop visibility SIPs in order to ``prevent any future

impairment'' as called for by the national goal in section 169A(a)(1).

Contracts received. The EPA received a number of comments on the

proposed applicability provisions. Many commenters approved of EPA's

approach to require SIPs from all States. Those who did not agree with

the scope of the program provided a number of reasons for their

opposition. Some commenters recognized the need for a regional haze

program, but stated that EPA must first conduct or review

[[Page 35721]]

additional scientific analyses in order to provide justification for

requiring additional States to submit visibility SIPs. Other commenters

felt that in the proposed applicability provisions, EPA exceeded its

statutory authority by extending the regional haze program to States

that have not been demonstrated to ``cause or contribute'' to

visibility impairment. Some commenters suggested that EPA rely on

States with Class I areas to engage nearby States, as appropriate, in

regional planning efforts. Some commenters in States containing Class I

areas suggested that, for their particular Class I areas, there was no

demonstrated visibility problem. They asserted that because visibility

levels should already be deemed acceptable, there was no need for a

regional haze program in their States. Other commenters felt that EPA

should include specific criteria (e.g., distance, emissions, and

visibility impact cutoffs) for excluding States or geographic areas

from consideration as contributing to regional haze visibility

impairment.

Final rule. Consistent with the proposal, EPA has concluded in

today's final rule that all States contain sources whose emissions are

reasonably anticipated to contribute to regional haze in a Class I area

and, therefore, must submit regional haze SIPs. The rationale for this

finding is discussed in more detail below.

In making this finding, EPA considered three factors: (1) The

specific statutory language in the CAA; (2) the weight of evidence

demonstrating long-range transport of fine particulate pollution that

affects visibility in Class I areas; and (3) current monitored

conditions in Class I areas across the country. The EPA's consideration

of each of these factors is discussed below.

Two key provisions in section 169A support EPA's finding that all

States must develop SIPs for regional haze. Section 169A(b)(2) requires

EPA to promulgate regulations to require SIPs from those States where

the emissions ``may reasonably be anticipated to cause or contribute to

any impairment of visibility'' in a mandatory Class I Federal area. The

EPA believes that this provision does not require the Agency to provide

absolute certainty regarding the effect of emissions from the State on

visibility in a particular Class I area.

The Ninth Circuit has interpreted the language, ``may reasonably be

anticipated to cause or contribute to any impairment of visibility,''

in a case involving identical language in section 169A(b)(2)(A)

relating to BART.42 The EPA believes that the court's

interpretation of this phrase may be appropriately used in regard to

program applicability as well. In its decision, the court found that

the language ``may reasonably be anticipated to cause or contribute''

establishes an ``extremely low triggering threshold'' for requiring a

source to control emissions, adding that ``the NAS correctly noted that

Congress has not required ironclad scientific certainty establishing

the precise relationship between a source's emission and resulting

visibility impairment. * * *'' 43 In considering whether

additional States should be subject to the visibility program, EPA

believes the court's reasoning supports adoption of the predicate

requirement that States develop the necessary provisions in their

implementation plans to determine whether and to what extent control of

emissions from sources is needed. That is, given that the court

believed this ``low triggering threshold'' was sufficient to require a

source to control its emissions under BART, EPA believes it is

reasonable that a similarly low or even lower threshold applies to

whether States should be required to engage in air quality planning and

analysis as a prerequisite to determining the need for control of

emissions from sources within their State. The EPA believes this is

particularly appropriate since the requirement for SIPs does not

mandate the actual control of emissions from any source without further

technical analysis by the State. Accordingly, EPA believes the concept

of an ``extremely low triggering threshold'' can also apply in

determining which States should submit SIPs for regional haze.

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\42\ Central Arizona Water Conservation District v. EPA, 990

F.2d 1531 (1993).

\43\ 990 F.2d at 1541.

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Section 169A(a)(1) sets forth a national goal of ``the prevention

of any future, and the remedying of any existing, impairment of

visibility in Class I areas which impairment results from manmade air

pollution.'' Thus, in addition to requiring a program to reduce

existing impairment, the CAA requires SIPs to be established in order

to prevent future impairment. This preventative component of the

national goal requires that States have the framework in place to

address future growth in emissions from new sources or other activities

that could impair visibility. For this reason, the EPA does not believe

that it is appropriate to establish criteria for excluding States or

geographic areas from consideration as potential contributors to

regional haze visibility impairment.

As noted in the proposal, EPA is not specifying in this final rule

what specific control measures a State must implement in its initial

SIP for regional haze. That determination can only be made by a State

once it has conducted the necessary technical analyses of emissions,

air quality, and the other factors that go into determining reasonable

progress. As discussed in section II(F), because of the regional,

multistate nature of visibility impairment in Class I

areas,44 EPA recommends that these analyses and the

determination of the extent of emissions reductions needed from

individual States be developed and refined through multistate planning

efforts using the best available technical tools, such as regional-

scale modeling. The EPA also recommends the coordination of resulting

strategies for regional haze with strategies needed to attain the

PM2.5 NAAQS. The EPA anticipates that as a result of the

more refined analyses required by this rule, some States may conclude

that control strategies specifically for protection of visibility are

not needed at this time because the analyses may show that existing

measures are sufficient to meet reasonable progress goals. The EPA is

requiring States to document their analyses, including any

consultations with other States in support of their conclusions that

further controls are not needed at this time. The EPA believes that

there is more than sufficient evidence to support our conclusion that

emissions from each of the 48 contiguous States may be reasonably

anticipated to cause or contribute to visibility impairment in a Class

I area.

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\44\ Refer to unit II of this final rule for additional

background on the long-range transport of pollution contributing to

regional haze.

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As stated in EPA's proposal, a large body of evidence demonstrates

that long-range transport of fine PM contributes to regional haze and

other related effects such as acid rain. In the preamble to the

proposal and in the relevant docket, EPA cited numerous studies that

contribute to this body of evidence.45 Indeed, EPA

recognized the role of long-range transport in relation to visibility

impairment 20 years ago in its 1979 Report to Congress on

visibility.46

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\45\ See Unit II, Background Information. See also July 29, 1997

memorandum to regional haze docket A-95-38, ``Supporting Information

for Proposed Applicability of Regional Haze Regulations,'' by

Richard Damberg, EPA, Office of Air Quality Planning and Standards.

\46\ U.S. EPA, Protecting Visibility: An EPA Report to Congress,

Office of Air Quality Planning and Standards, EPA-450/5-79-008,

October 1979.

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Among the more important studies on which EPA relied are the 1991

report from the NAPAP, the 1993 NAS report Protecting Visibility in

National Parks

[[Page 35722]]

and Wilderness Areas, EPA studies using the regional acid deposition

model (RADM), the 1996 GCVTC report Recommendations for Improving

Western Vistas, and two contractor reports prepared for

EPA.47 All of these reports are available in the docket.

They were referenced and discussed in EPA's proposal and in an

additional memorandum to the docket. The NAPAP report included a

comprehensive technical review of historical visibility

trends.48 The NAS report found that the range of fine

particle transport is on the order of hundreds or thousands of

kilometers.49 Analyses using the RADM have estimated that

sulfate and nitrate deposition receptors are influenced by sources

located up to 600-800 kilometers away.50 In its

deliberations and in its final report, the GCVTC acknowledged the role

of long-range transport from sources and activities located across a

very large geographic area, and its effect on the Class I areas on the

Colorado Plateau.51

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\47\ See Latimer and Associates, Particulate Matter Source--

Receptor Relationships Between All Point and Area Sources in the

United States and PSD Class I Area Receptors, Report prepared for

EPA, Office of Air Quality Planning and Standards, September 1996.

See also ENVIRON International Corporation, Development of Revised

Federal Class I Area Groups in Support of Regional Haze Regulations,

Report prepared for EPA, Office of Air Quality Planning and

Standards, September 1996.

\48\ National Acid Precipitation Assessment Program. Acid

Deposition: State of the Science and Technology. Report 24,

Visibility: Existing and Historical Conditions--Causes and Effects,

Washington, DC, 1991.

\49\ National Research Council, NAS Committee on Haze in

National Parks and Wilderness Areas, Protecting Visibility in

National Parks and Wilderness Areas, National Academy Press,

Washington, D.C., 1993.

\50\ Dennis, Robin L. ``Using the Regional Acid Deposition Model

to Determine the Nitrogen Deposition Airshed of the Chesapeake Bay

Watershed,'' in Atmospheric Deposition to the Great Lakes and

Coastal Waters, edited by Joel Baker, 1996.

\51\ GCVTC, Recommendations for Improving Western Vistas, Report

to the U.S. EPA, June 1996.

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Finally, two contractor modeling reports prepared for EPA provided

information that preliminarily demonstrated that each State not having

a Class I area had emissions contributing to impairment in at least one

downwind Class I area. Some State commenters asserted that the

contractor reports referenced in the proposal show relatively low

contributions from all or part of their States toward visibility

impairment in a nearby Class I area. As a result, these commenters

suggested that EPA had sufficient information to reach a conclusion

that all or part of their States could be excluded from the regional

haze program. The EPA disagrees with these comments for two reasons.

First, the EPA did not base its proposed applicability provisions

only on the referenced contractor reports. The EPA based its decision

on the assessments provided by these reports as well as a number of

other studies and sources of information. Second, as explained above,

EPA believes that all States must have a visibility SIP to prevent, at

a minimum, future impairment of visibility. While EPA agrees that

portions of some States may not need to implement additional measures,

at this time, to improve visibility impairment in any Class I area, the

EPA believes that more refined future assessments will be needed to

support such a finding. Additionally, the EPA believes that a State

wishing to demonstrate that it does not contribute to visibility

impairment in any Class I area will need to provide information showing

that it has consulted with other potentially affected States to assist

EPA in assuring that the State's demonstration is not contradicted by

evidence presented by other States.

Current monitoring information for Class I areas shows that all of

the monitored sites in the central and eastern parts of the country

have visibility impairment levels exceeding estimated natural

conditions for the 20 percent most impaired days, some by more than 20

deciviews. Although the degree of impairment varies, the data

demonstrate that no existing site has reached the goal in section

169A(a)(1) of the CAA for ``remedying * * * any existing impairment of

visibility.'' \52\

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\52\ Sisler, J. et al., Spatial and Seasonal Patterns and Long-

Term Variability of the Chemical Composition of the Haze in the

United States: An Analysis of Data from the IMPROVE Network, Fort

Collins, CO, Cooperative Institute for Research in the Atmosphere,

Colorado State University, 1996. See also Sisler, J., et al.,

Spatial and Temporal Patterns and the Chemical Composition of the

Haze in the United States: An Analysis of Data from the IMPROVE

Network, 1988-1991, Fort Collins, CO, 1993.

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In light of this finding, EPA disagrees with the commenter who

asserted that because visibility levels in its State are already

``acceptable,'' there is no need for the State to implement a regional

haze program. The section 169A national goal of the visibility program,

a condition of no human-caused impairment, does not provide for

judgments of acceptable visibility levels which are poorer than natural

conditions in Class I areas. Through adoption of section 169A(a)(1),

Congress established natural visibility conditions as the overall goal.

The data also show that in the monitored locations in the central

and eastern United States, sulfate is the key contributor to visibility

impairment, responsible for between 45-90 percent of light extinction

due to aerosols on the 20 percent most impaired days. This fact is

significant because the broad, regional scale of long-range transport

of sulfate has already been acknowledged in many studies done for the

acid rain program. Based on these data, it appears that although the

acid rain program is expected to improve visibility by approximately 3

deciviews in the most impaired Class I areas in the Eastern United

States by 2005,\53\ further regional reductions in SO2

emissions may be needed after the acid rain program is complete to

assure continued visibility improvement toward the national goal. Thus,

EPA finds it is reasonable to require SIPs from the States without

Class I areas which are located in the central and eastern parts of the

United States since many, if not all, are expected to have sources

contributing to regional loadings of SO2 emissions, even

after implementation of the acid rain program is completed.

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\53\ U.S. EPA, Effects of the 1990 Clean Air Act Amendments on

Visibility in Class I Areas: An EPA Report to Congress, Office of

Air Quality Planning and Standards, EPA-452/R-93-014, October 1993.

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For all of the reasons stated above, EPA has concluded in today's

final rule that EPA's statutory authority and scientific evidence are

sufficient to require all States to develop regional haze SIPs to

ensure the prevention of any future impairment of visibility, and to

conduct further analyses to determine whether additional emission

reduction measures are needed to ensure reasonable progress in

remedying existing impairment in downwind Class I areas.

B. Timetable for Submitting the First Regional Haze State

Implementation Plan (SIP)

This final rule establishes a schedule setting forth deadlines by

which the States must submit their first regional haze SIPs and

subsequent revisions to that first SIP. In this unit, we discuss the

deadlines for the first regional haze SIP, the concerns raised in

comments regarding these deadlines, and recent legislation affecting

the deadlines. The requirements for periodic revisions to this first

regional haze SIP are discussed below in unit III.J.

Proposed rule. The proposed rule, consistent with section

169B(e)(2) of the CAA, would have required States to submit revisions

to their SIP to address regional haze within 12 months of the effective

date of the rule. We had intended that these 12-month SIP

[[Page 35723]]

submittals serve as program planning SIPs in which the States would

review existing regulatory authorities and provide the framework for a

number of future actions.

Comments received. Commenters expressed the view that 12 months was

an insufficient time period to meet the proposed requirements for the

program planning SIP. Moreover, commenters were concerned that the 12-

month SIP requirement was not well coordinated with similar program

planning for the new PM2.5 standard.

Transportation Equity Act for the 21st Century (TEA-21). After the

close of the comment period for the July 1997 proposal, Congress passed

the Transportation Equity Act for the 21st Century (TEA-21), Public Law

105-178. The TEA-21 superseded the statutory requirement for a 12-month

SIP deadline and established a specific schedule for regional haze SIP

submissions. In a September 3, 1998 notice of availability, EPA

provided the public with an opportunity to comment on how the regional

haze rule should address the TEA-21 requirements.\54\

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\54\ 63 FR 46952.

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The TEA-21 provisions establish a timetable for the regional haze

SIPs by first creating certain deadlines for PM2.5

monitoring and area designations, and then by linking those deadlines

to further deadlines for the regional haze program. The TEA-21

amendments, in section 4102(a), require EPA to fund a PM2.5

monitoring network. In section 4102(b), EPA and States are required to

put this network in place by no later than December 31, 1999.

Section 4102(c)(1) of TEA-21 establishes deadlines for States to

use the data collected by the network for purposes of formally

designating areas as attaining the PM2.5 standard or as

nonattainment or unclassifiable. Section 4102(c)(1) states:

(1) The Governors shall be required to submit designations

referred to in section 107(d)(1) of the CAA for each area following

promulgation of the July 1997 PM2.5 national ambient air

quality standard within 1 year after receipt of 3 years of air

quality monitoring data performed in accordance with any applicable

Federal reference method for the relevant areas.

Section 4102(c)(2) of TEA-21 contains the following language which

links the timing requirements for the visibility program to the

PM2.5 designation process:

(2) For any area designated as nonattainment for the July 1997

PM2.5 national ambient air quality standard in accordance

with the schedule set forth in this section, notwithstanding the

time limit prescribed in paragraph (2) of section 169B(e) of the

CAA, the Administrator shall require State implementation plan

revisions referred to in such paragraph (2) to be submitted at the

same time as State implementation plan revisions referred to in

section 172 of the CAA implementing the revised national ambient air

quality standard for fine particulate matter are required to be

submitted. For any area designated as attainment or unclassifiable

for such standard, the Administrator shall require the State

implementation plan revisions referred to in such paragraph (2) to

be submitted 1 year after the area has been so designated. The

preceding provisions of this paragraph shall not preclude the

implementation of the agreements and recommendations set forth in

the GCVTC Report dated June 1996.

To accompany the statutory changes contained in the TEA-21 law,

Congress released a Conference Report. With respect to the visibility

provisions of TEA-21, the Conference Report states:

The Conferees recognize that the Regional Haze regulation has

not been finalized and the Administrator of the Environmental

Protection Agency (EPA) is still considering the views of various

stakeholders. The Conferees agree with EPA's public statements that

the schedule for the State Implementation Plan due pursuant to

section 169B(e)(2) of the * * * [Clean Air] * * * CAA should be

harmonized with the Schedule for State Implementation Plan

submissions required for PM2.5 ambient air quality

standard promulgated in July, 1997.\55\

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\55\ H.R. Conf. Rep. No. 550, 105th Cong., 2d. Sess. 519 (1998),

reprinted in 1998 U.S.C.C.A.N., No. 6 at 196.

This new statutory language has two effects. First, it supersedes the

section 169B requirement for EPA to require States to submit SIPs

within 12 months of the promulgation of today's final rule. Second, it

spells out a timetable for SIP revisions that is linked to the dates of

attainment/nonattainment designations for PM2.5. It is

important to note that the timetable is based on the designation of

areas within a State. Thus, under the legislation, one State could have

multiple SIP submission deadlines depending on the dates of designation

of each area within the State. This issue, and how EPA intends to

address it, is further discussed later in this unit.

According to a Presidential memorandum dated July 16, 1997, the EPA

and States must collect 3 years of monitoring data in order to have a

sufficient basis for designations. This point is reiterated in TEA-

21.\56\ Routine collection of monitoring data begins in 1999. Hence, we

expect the requirements of TEA-21, section 4102(c)(1), to result in the

following:

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\56\ See TEA-21, Section 4102(c)(1).

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Submissions of designation requests by States. States must submit

designations within 1 year of the date that 3 years of PM2.5

data are available. Because widespread monitoring for PM2.5

is being implemented between January 1999 and December 31, 1999, we

expect 3 years of data to be collected by December 31, 2001 for most

areas and no later than December 31, 2002 for the remaining areas.

Taking into account additional time (not more than 6 months) for

quality assurance and certification of the data, we expect 3 years of

data to be available for States to use for designations between July

2002 and July 2003. In the TEA-21 amendments, States have up to 1 year

to submit designations. Thus, we expect that the required date for

submittal of designations generally will occur between July 2003 and

July 2004.\57\

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\57\ We expect that some States will want to move expeditiously

with some designations, leading to submissions and final action on

some areas as early as late 2002 or early 2003. Where this is the

case, this would lead to earlier regional haze SIP submittal

deadlines as well.

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EPA action on State designations. The EPA is required to act upon

the designations no later than 1 year after the date States are

required to submit the designations, but not later than December 31,

2005 in any case. If States submit their designations between July 2003

and July 2004, EPA would be required to designate areas between July

2004 and July 2005.

For areas designated as attainment or unclassifiable, the TEA-21

amendments require that States must submit SIPs for regional haze

within 1 year after EPA publishes the designations. As a result, for

these areas, regional haze SIPs are likely to be due generally between

July 2005 and July 2006.

For areas designated as nonattainment for fine particulate matter,

the TEA-21 amendments require States to submit SIP revisions addressing

regional haze ``at the same time as States submit SIPs as required by

section 172 of the CAA implementing the July 1997 revision to the

national ambient air quality standard for fine particulate matter.''

Section 172(b) of the CAA requires SIPs no later than 3 years after EPA

publishes the nonattainment designation. If EPA designates areas

nonattainment between July 2004 and July 2005, the regional haze SIPs

for areas designated as nonattainment and the PM2.5

nonattainment SIPs would both be due no later than the July 2007 to

July 2008 timeframe.

The date for startup of PM2.5 monitoring may vary in

different parts of a given State. Accordingly, the EPA expects that

States may not be able to submit designation requests at the same time

for the entire State. Rather, EPA

[[Page 35724]]

expects that it is possible that individual ``areas'' within a given

State may be designated at different times. Even if areas were all

designated at the same time, in many States some areas will likely be

designated attainment, with others designated nonattainment. In either

case, the TEA-21 deadlines would require separate regional haze SIPs

for each of these areas to be submitted at different times.

While the language in TEA-21 establishing the timetable for

submission of regional haze SIPs is generally clear, the transportation

legislation does not address the situation where States are

participating in a regional planning effort that incorporates numerous

areas. On its face, TEA-21 requires the submission of separate regional

haze SIPs on an area-by-area basis with varying deadlines that could

range over a period of several years. As noted above, however, regional

haze is the result of emissions from a number of sources located over a

broad geographic area. Because of the long-range transport of

pollutants causing regional haze, EPA believes that well-coordinated

regional planning efforts are needed to make progress toward natural

visibility conditions. As EPA noted in the September 3, 1998 notice of

availability, we do not believe that Congress intended to inhibit

regional planning efforts by requiring area-by-area submittals. In

light of this, EPA requested comment on incorporating an optional

approach into the final rule to facilitate regional planning.

Notice of availability of additional information. The optional

approach EPA described in the September 3, 1998 notice of availability

would allow States which commit to participating in regional planning

efforts to postpone addressing certain of the requirements of the

regional haze program. Under this approach, States would have the

option to first submit SIPs which contain commitments to specific

integrated regional planning efforts but which do not set forth control

strategies. States committing to regional planning would subsequently

submit SIP revisions containing control strategies for attainment,

unclassifiable, and nonattainment areas at the same time. This would

allow multiple areas within a single planning region to have

coordinated deadlines for regional haze control strategies. In the

supplemental notice, we noted that this approach could have the effect

of delaying control strategy plan submittal dates for some areas, but

we believe that such an option will support more effective coordination

between the PM2.5 and regional haze programs, will support

coordinated regional planning for both programs, and will be consistent

with the statement of congressional intent.

Comments received. Some commenters argued that TEA-21 does not

authorize EPA to defer implementation of the regional haze program in

this way. The basis for this argument is the claim that the 1-year

deadline in section 169B(e)(2) applies only to regulations promulgated

pursuant to the report of a visibility transport commission. These

commenters claim that EPA is obligated under section 169A to provide

for more expedited implementation of measures to assure reasonable

progress.

The final rule. The regulations made final today are issued under

the authority of CAA sections 169A and 169B. As discussed in unit II.C

above, EPA in 1980 explicitly deferred issuing regulations to address

regional haze until our scientific and technical knowledge was better

developed. In 1990, Congress amended the CAA by adding section 169B.

This section authorizes the establishment of visibility transport

commissions which, among other things, must issue a report addressing

``the promulgation of regulations under [section 169A] to address long

range strategies for addressing regional haze.'' Section 169B further

establishes explicit timeframes in which EPA must, taking into account

any reports of visibility transport commissions, issue regulations

under section 169A, and in which States must respond by submitting

revised SIPs. Congress modified the timeframe for SIP submission in

TEA-21 to ensure the ability of EPA to harmonize the implementation of

today's final rule with the requirements for the new PM2.5

NAAQS.\58\ Today's final rule carries out EPA's obligation under

sections 169A and 169B to issue regulations addressing regional haze

according to the timeframe as set forth in section 169B as modified by

TEA-21.

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\58\ See H.R. Conf. Rep. No. 550, 105th Cong., 2d. Sess. 517.

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

The final rule includes the deadlines for SIP submittals set forth

in TEA-21 and incorporates an optional set of requirements for States

which commit to participate in regional planning. Commenters generally

agreed with EPA's view in the notice of availability that it is

important to ensure that the PM2.5 program and regional haze

program are fully integrated. The EPA believes that the approach taken

in the final rule supports effective coordination between these

programs, while also facilitating regional planning.

In the final rule, the timetable for SIP submittals is set forth in

section 51.308(b) and (c). Section 51.308(b) directly codifies the TEA-

21 timetable. Section 51.308(c) provides States that have committed to

participate with other States in a regional planning process the option

of choosing to defer submittal of a SIP which addresses the substantive

requirements of the regional haze program. States are not required to

exercise the option provided by section 51.308(c), but those which do

must meet the deadlines set forth in that section for submitting a SIP

which addresses the distinct requirements in section 51.308(c) and a

SIP revision which addresses the substantive requirements of the

regional haze program.\59\

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\59\ The option for regional planning provided by section

51.308(c) is not available for Alaska, Hawaii, and the Virgin

Islands. Class I areas within their boundaries are not affected by

emissions from any other State. As a result, regional planning will

not be needed to develop regional haze SIPs for these areas.

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

As a first step, States electing to participate in regional

planning must submit a SIP demonstrating the State's ongoing

participation in a regional planning process. This SIP must address all

areas in the State and is due on the earliest date by which an

implementation plan affecting any area within the State would be due

under the TEA-21 deadlines. Unless an entire State is designated as

nonattainment, this SIP will be due 1 year after EPA designates any

area within the State as attainment or unclassifiable. This SIP

submission must contain a number of specific elements to demonstrate

the State's commitment to the regional planning process and to ensure

that by the date of the SIP submittal, the States in the regional

planning body have taken the necessary steps to initiate the regional

planning process.

The following briefly summarizes the required elements of the first

SIP submittal called for under the optional approach for regional

planning:

Need for regional planning. In the SIP, the State must demonstrate

the need for regional planning. The State must make this demonstration

by showing that emissions from sources within the State contribute to

visibility impairment in Class I areas in another State, or by showing

that other States contribute to visibility impairment in the Class I

areas in the State. The EPA does not intend for this to be an overly

complex analysis.

Description of regional planning organization. The State must also

submit a detailed description of the regional planning process. In its

SIP, the State must show that the participating

[[Page 35725]]

States have a credible regional planning process in place which all

parties are committed to follow. We have outlined general principles

for regional planning organizations in a document entitled

Implementation Guidance for the Revised Ozone and Particulate Matter

(PM) National Ambient Air Quality Standards (NAAQS) and the Regional

Haze Program, which discusses features of effective regional planning

organizations, including a discussion of organization and

representation issues, issues related to developing workplans and

schedules, and issues related to ensuring that technical efforts are

consistent. This document is available on the internet at http://

www.epa.gov/ttn/oarpg/t1pgm.html.

Enforceable commitment to submit coordinated control strategy by

2008. The regional planning SIP must include provisions requiring the

State to submit a SIP revision meeting all of the requirements of the

regional haze rule. This SIP revision is due by the latest date an area

within the planning region would be required to submit an

implementation plan under TEA-21, but in no event any later than

December 31, 2008. The SIP must require that the SIP revision is

developed in coordination with the other States in the regional

planning body and that it fully addresses the recommendations of that

body.

List of BART-eligible sources. The State must identify those

sources from one of 26 source categories and placed into operation

between 1962 and 1977 that are potentially subject to BART. This

information will enable the State and regional planning organization to

begin evaluating options for meeting the BART requirement or for

implementing an emissions trading program or alternative measure that

achieves greater reasonable progress.

Summary of timetable for submission of the first regional haze

SIPs. The following table is a summary of the deadlines for submitting

the first regional haze SIPs.

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

. . . States must

submit the first . . . and the SIP

For this case . . . regional haze SIPs must meet . . .

no later than:

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

Areas designated as 1 year after EPA ALL requirements of

attainment or publishes the section 51.308(d)

unclassifiable for PM2.5. designation and (e).

(generally 2004-

2006).

Areas designated as At the same time as ALL requirements of

nonattainment for PM2.5. PM2.5 SIPs are due section 51.308(d)

under section 172 and (e).

of the CAA. (That

is, 3 years after

EPA publishes the

designation,

generally 2006-

2008).

States participating in Two phases:......... The regional

multistate regional Commitment to planning

planning efforts for regional planning requirements listed

combined attainment and due 1 year after in section

nonattainment areas. the EPA publishes 51.308(c).

the first

designation for any

area within the

State, and.

Complete The ``core

implementation plan requirements''

due at the same listed in section

time as PM2.5 SIPs 51.308(d) and BART

are due under requirements in

section 172 of the section 51.308(e).

CAA. (That is, 3

years after EPA

publishes the

designation).

States following the December 31, 2003... SIPs must meet the

recommendations of the specific provisions

GCVTC, as contained in for Grand Canyon

section 51.309 of the final Transport Region

rule. States listed in

section 51.309.

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

C. Tracking Deciviews and Emissions Reductions

Visibility impairment is caused by particles and gases in the

atmosphere. Some particles and gases scatter light, while others absorb

light. The net effect is called ``light extinction.'' The result of

these processes is a reduction of the amount of light from a scene that

is returned to the observer, creating a hazy condition.

Proposed rule. In the proposal, EPA established a regulatory

framework by which a State would establish a ``reasonable progress

target'' for each Class I area within its borders for the purpose of

improving visibility on the worst visibility days over the next 10 or

15 years. The States would implement emission management strategies to

improve visibility in these Class I areas. The proposal also called for

the States to monitor progress in improving visibility over time. The

EPA proposed that visibility targets and tracking of visibility changes

over time be expressed in terms of the ``deciview'' haze metric. The

proposal also called for the tracking of pollutant emissions to

supplement the tracking of monitored visibility changes for use in

periodically reviewing State progress in achieving visibility targets.

The proposal included the definition of the deciview metric for

tracking visibility. The proposal also called for a review of emissions

reductions achieved as part of the long-term strategy.

Deciview. The proposal explained that the deciview is an

atmospheric haze index that expresses changes in visibility. This

visibility metric expresses uniform changes in haziness in terms of

common increments across the entire range of visibility conditions,

from pristine to extremely hazy conditions.60 Because each

unit change in deciview represents a common change in perception, the

deciview scale is like the decibel scale for sound. The proposal also

stated that ``A one deciview change in haziness is a small but

noticeable change in haziness under most circumstances when viewing

scenes in Class I areas.'' 61

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\60\ Pitchford, M. and Malm, W., ``Development and Applications

of a Standard Visual Index,'' Atmospheric Environment, v. 28, no. 5,

March 1994.

\61\ 62 FR 41145.

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The proposal discussed that an advantage to using the deciview over

other scales is that it can be used to express changes in visibility

impairment in a way that corresponds to human perception in a linear,

or one for one, manner. For example, this metric is designed such that

a change of 3 deciviews in a highly impaired environment would be

perceived as roughly the same degree of change as a 3 deciview change

in a relatively clear environment. As noted in the preamble to the

proposed regulation, the deciview is mathematically related to other

common metrics used to describe visibility: the light extinction

coefficient and visual range. However, the deciview metric can be used

to compare changes in perception in a way that the other two metrics

cannot. This feature makes the deciview a more useful metric for

regulatory purposes. For example, a 5-

[[Page 35726]]

mile change in visual range can in some cases be very significant, such

as from 5 to 10 miles in an impaired environment (equal to a change of

6.9 deciviews), whereas a 5-mile change may not be perceptible in a

less impaired environment, such as from 95 to 100 miles (equal to a

change of 0.5 deciviews). The following sections discuss the comments

received on specific issues and how such issues are addressed in the

final rule.

Tracking emissions versus visibility. Many commenters supported the

use of the deciview metric to track changes in visibility improvement

as a key aspect of the program. These commenters agreed with EPA's

proposal that under a visibility-oriented program, progress in fact

should be tracked in terms of a visibility-based metric. Others felt

the program could be successfully implemented by tracking emissions

only because this approach would not be greatly affected by

meteorological variations as would an approach based on ambient

monitoring.

The final rule provides for the tracking of both visibility

improvement and emissions reductions.62 The final rule

presents visibility improvement and tracking of emissions as linked

elements of the program. The EPA has retained the use of the deciview

metric for tracking changes in visibility. The EPA believes the

tracking of actual visibility improvements is necessary to be

responsive to the goals of the CAA. Section 169A(a) of the CAA sets

forth the national goal of the ``prevention of any future, and the

remedying of any existing, impairment of visibility in Class I areas

which impairment results from manmade air pollution.'' The CAA also

requires EPA to establish regulations to be implemented by the States

to ensure that `reasonable progress' is made toward the national goal.

In addition, section 169B(e) of the CAA calls for EPA to carry out its

``regulatory responsibilities under section 169A, including criteria

for measuring `reasonable progress' toward the national goal.''

63

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\62\ Tracking of visibility is addressed in section 51.308(d)

and 51.308(g). Tracking of emissions reductions is addressed in

section 51.308(g).

\63\ Section 169B(e)(1).

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The EPA believes that tracking of emissions reductions is also an

important component of the regional haze program. The mechanism for

achieving improvements in visibility will be the implementation of

enforceable emissions reduction measures that have been adopted as part

of the SIP. Tracking emissions will provide a good indicator of whether

adopted measures are reducing emissions and is thus a useful indicator

of progress in reducing visibility impairment. The tracking of

emissions without concurrently tracking changes in visibility, however,

would be problematic because of the variable effect on visibility of

each of the principal constituents of PM, the more significant light

scattering efficiency of fine PM versus coarse PM, and the generally

greater effect of nearby versus distant sources on visibility

impairment.

Since the national goal is expressed in terms of air quality (i.e.,

visibility) rather than emissions, we believe that it is very important

to require the quantitative tracking of visibility impairment as an

integral element in measuring reasonable progress. Because ambient

monitoring data are subject to meteorological fluctuations, EPA designs

standards and requirements for analysis of monitoring data to limit the

effects of unusual meteorological events. For regional haze, we have

provided in this final rule for the tracking of visibility trends based

on 5-year averages of annual deciview values for the most impaired and

least impaired days. We believe that this approach responds to

commenters' concerns about significant unusual fluctuations in annual

average values for the best and worst days due to unusual

meteorological conditions in any particular year. However, it is also

important to note that EPA has long held that normal meteorological

variations should be explicitly accounted for in air quality analyses

and control strategy design. Air quality improvement plans should be

able to assure protection of public health and welfare under the normal

and foreseeable range of meteorological conditions.

Tracking visibility in deciviews. Some commenters disagreed with

the use of the deciview to measure changes in visibility, claiming that

the deciview metric has not been adequately reviewed for use in a

regulatory program. The EPA disagrees with this assertion. The EPA

believes the deciview metric has been adequately reviewed for use in

the regional haze program. The deciview concept was introduced in 1994

in an article appearing in the peer-reviewed journal Atmospheric

Environment.64 It was presented in the 1996 Criteria

Document for the PM NAAQS as a valid metric for characterizing

visibility impairment.65 The EPA also recognized the

deciview as an appropriate metric for regulatory purposes in chapter 8

of the 1996 Staff Paper for the PM NAAQS review.66 Both of

these documents were reviewed and accepted by the Clean Air Scientific

Advisory Committee. Visibility conditions at Class I areas have been

characterized in terms of deciview in summary reports on the IMPROVE

visibility monitoring network.67

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\64\ Pitchford, M. and Malm, W., ``Development and Applications

of a Standard Visual Index,'' Atmospheric Environment, V. 28, no. 5,

March 1994.

\65\ U.S. EPA, Air Quality Criteria for Particulate Matter,

Research Triangle Park, NC, National Center for Environmental

Assessment. Office of Research and Development, July 1996.

\66\ U.S. Environmental Protection Agency. Review of the

National Ambient Air Quality Standards for Particulate Matter:

Policy Assessment of Scientific and Technical Information. OAQPS

Staff Paper. Office of Air Quality Planning and Standards. July

1996.

\67\ Sisler, J., et al., Spatial and Seasonal Patterns and Long-

Term Variability of the Composition of the Haze in the United

States: An Analysis of Data from the IMPROVE Network. Cooperative

Institute for Research in the Atmosphere, Colorado State University,

1996. See also Sisler, J., et al., Spatial and Temporal Patterns and

the Chemical Composition of the Haze in the United States: An

Analysis of Data From the IMPROVE Network, 1988-1991, Fort Collins,

CO, 1993.

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

The EPA also supports use of the deciview metric because it

satisfies one of the recommendations of the NAS Committee on Haze in

National Parks and Wilderness Areas. In its 1993 report on visibility,

the NAS recommended the development of an index that takes into account

both measurement of physical changes (i.e., changes in air quality)

with elements of human perception.68 Further, a report on

the regional haze proposal by the Congressional Research Service found

that the deciview index ``conforms closely'' 69 to the NAS

recommendation cited above.

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\68\ National Research Council, Protecting Visibility in

National Parks and Wilderness Areas, 1993, p. 354.

\69\ Congressional Research Service, Regional Haze: EPA's

Proposal to Improve Visibility in National Parks and Wilderness

Areas, November 17, 1997, p. 17.

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Some commenters stated that the final rule should not suggest that

a one deciview change is the threshold of perception in all cases for

all scenes. The EPA agrees with the comment that a one deciview change

should not be considered the threshold of perception in all cases for

all scenes. The EPA believes that visibility changes of less than one

deciview are likely to be perceptible in some cases, especially where

the scene being viewed is highly sensitive to small amounts of

pollution. The EPA also acknowledges the technical point made by some

commenters that for other types of scenes with other site-specific

[[Page 35727]]

conditions,70 a change of more than 1 deciview might be

required in order for the change to be perceptible. However, EPA wishes

to emphasize that the overall goal of the regional haze program is not

to track changes in visibility for only certain vistas at a specific

Class I area. Rather, the program is designed to track changes in

regional visibility for the range of possible views of sky and terrain

found in any Class I area, and to assure progress toward the national

goal. For this purpose, EPA supports the use of the deciview metric as

calculated from ambient monitoring data for tracking changes in

regional visibility. The monitoring network is not designed to track

changes in visibility for specific views in each Class I area. Rather,

the network is designed to characterize visibility conditions that, for

each site, are representative of a fairly broad geographic region. The

EPA believes this approach is consistent with the nature of regional

haze, which is defined as a uniform haze caused by numerous sources

covering a broad area. Thus, although a 1 deciview change may not be

the threshold of perception in all situations, the fundamental

advantage of using the deciview remains: the deciview metric expresses

uniform changes in haziness in terms of common increments across the

entire range of visibility conditions, from pristine to extremely hazy

conditions. The metric provides a useful means of expressing changes in

visibility caused by changes in air quality while also providing a

scale that relates visibility to perception. The final rule maintains

the deciview as the principle visibility metric used in establishing

reasonable progress goals, in defining baseline, current, and natural

conditions, and in tracking changes in visibility conditions over time.

States may choose to express visibility changes in terms of other

metrics, such as visual range or light extinction, as well as in terms

of deciview. The definition in the final rule was modified slightly to

provide additional clarity.

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\70\ For example, where the sight path to a scenic feature is

less than the maximum visual range.

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Light extinction calculated from aerosol data. Some other

commenters did not support EPA's proposed approach to calculating light

extinction based on monitored fine particle data (referred to as

``reconstructed light extinction'' in the proposal). These commenters

preferred other methods, such as direct measurement of light scattering

or light extinction with an optical device. While such methods are

desired in comprehensively monitoring visibility impairment, the EPA

supports the use of a common approach for calculating visibility

changes based on monitored fine particle data as the primary monitoring

method for tracking visual air quality.

Such an approach has been established and implemented for many

years by the IMPROVE Steering Committee. The IMPROVE approach uses a

set of standard assumptions,71 which have been tested and

found to be reasonable, in calculating light extinction and deciviews

from changes in air quality. Two important aspects of the approach are:

(1) Standard rates of light extinction per unit mass of visibility-

impairing pollutants (e.g., sulfate, nitrate, organic carbon, elemental

carbon, and crustal material); and (2) standard effects of humidity on

sulfate and nitrate.

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

\71\ See Sisler, et al., Spatial and Seasonal Patterns and Long-

Term Variability of the Composition of the Haze in the United

States: An Analysis of Data from the IMPROVE Network. Cooperative

Institute for Research in the Atmosphere, Colorado State University,

1996.

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

Through extensive analysis of empirical data, a value (or ``dry

extinction coefficient'') has been developed for each aerosol component

which represents the amount of light extinction (expressed in inverse

megameters) caused by each microgram/m3 of that component. Light

extinction is calculated by multiplying the aerosol mass for each

component by its extinction coefficient and summing the products.

Because sulfates and nitrates become more efficient at scattering light

as humidity increases, the values for these two components are also

multiplied by a relative humidity adjustment factor. It has been shown

that annual and seasonal light extinction values developed according to

this method correlate well with averages of optical measurements of

light extinction for the same locations.\72\ The EPA plans to issue

future guidance describing the details of calculating visibility

changes in this manner and tracking visibility over time.

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

\72\ Id.

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Although light extinction can be measured directly by certain

optical devices (i.e., transmissometers and nephelometers), EPA

supports an approach based on the mass of PM components derived from

ambient monitoring for calculating light extinction for two main

reasons. First, this approach provides for the tracking of actual

changes in the components of air pollution, and the information

obtained from analysis of the chemical composition of PM is critical to

the air quality modeling and strategy development processes. By

understanding the chemical composition of particulate matter, we can

better define the manmade and natural components contributing to

overall light extinction. Second, direct measurements of visibility

from some optical instruments (e.g., transmissometer) are more

frequently disrupted by precipitation events (i.e., rain or snow) than

are aerosol measurements.

For all of the reasons discussed above, the final rule provides for

the tracking of visibility and emissions reductions. The deciview will

be the principal visibility metric for use in implementing the regional

haze program. The deciview will be used for expressing reasonable

progress goals, defining baseline, current, and natural conditions, and

tracking changes in visibility conditions over time. The definition of

deciview in the final rule in section 51.301(bb) was modified slightly

to provide additional clarity and state that deciview values are to be

derived from calculated light extinction based on aerosol measurements

in accordance with EPA guidance.

D. Regional Haze Implementation Plan Principles

Section 169A of the CAA calls for States to develop implementation

plans ensuring reasonable progress toward the national goal, including

emission limits, schedules of compliance and other measures as

necessary. At a minimum, the CAA calls for SIPs to include a long-term

strategy and provisions for BART for certain major stationary sources.

We would like to emphasize several overarching themes for the specific

implementation plan requirements in the final rule:

Regional haze regulations and State implementation plans

must address all of the statutory requirements outlined in 169A and

169B of the CAA. Regional haze requirements must address a number of

specific statutory requirements, including ``criteria for reasonable

progress,'' long-term strategies addressing all types of sources and

activities, and best available retrofit technology for certain

stationary sources. The implementation plan requirements in the final

rule are designed to ensure that all of these statutory requirements

will be met.

Tracking ``reasonable progress'' should involve the

tracking of both emissions and visibility improvement. Regional haze

implementation plans must include provisions for tracking the

implementation of enforceable emission management strategies designed

to make reasonable progress toward the national

[[Page 35728]]

visibility goal. Emission control measures will be the component that

will be enforceable to ensure reasonable progress. Measuring reasonable

progress should involve tracking the actual emissions achieved through

implementation of such strategies, and the tracking of visibility for

the most impaired and least impaired days using established monitoring

and data analysis techniques.

Strategies for improving visibility should address all

types of sources. Section 169A provides for State long-term strategies

to address all types of sources and activities emitting pollutants that

contribute to visibility impairment in Class I areas, including

stationary, mobile, and area sources. Implementation plans also must

give specific attention to certain stationary sources built between

1962 and 1977 and provide for meeting the BART provisions for these

sources.

Successful implementation of the regional haze program

will involve long-term regional coordination among States. Pollution

affecting the air quality in Class I areas can be transported long

distances, even hundreds of kilometers. Therefore, States will need to

develop strategies in coordination with one another, taking into

account the effect of emissions from one jurisdiction to air quality in

another. In addition, as noted by the NAS study, ``achieving the

national visibility goal will require a substantial, long-term

program.'' 73 Accordingly, the regional haze program

requires the periodic review by each State of whether ``reasonable

progress'' is being achieved and revisions of implementation plans as

needed to continue progress toward the national visibility goal.

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\73\ National Research Council, Committee on Haze in National

Parks and Wilderness Areas, Protecting Visibility in National Parks

and Wilderness Areas, National Academy Press, 1993.

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E. Determination of ``Baseline,'' ``Natural'' and ``Current''

Visibility

Background. The fundamental goal of the visibility program, as

provided by Congress, is the prevention of future visibility impairment

and the remedying of existing impairment in Class I areas. Thus, the

regional haze program must track progress toward the national goal.

In order to facilitate this tracking process, the proposed rule

required each State having one or more Class I areas to establish, and

update as necessary, three important visibility parameters for the best

and worst visibility days at each Class I area within the State. Each

parameter is discussed in detail below.

Baseline conditions--Baseline conditions represent

visibility for the best and worst days at the time the regional haze

program is established. Baseline conditions are calculated using

multiyear averaging.

Natural conditions--As specified in the CAA, estimated

natural conditions, or the visibility conditions that would be

experienced in the absence of human-caused impairment, constitute the

ultimate goal of the program. Under the regional haze program, natural

conditions need to be estimated for the 20 percent best and worst days.

Current conditions--Current conditions for the best and

worst days are calculated from a multiyear average, based on the most

recent years of monitored data. This value would be revised at the time

of each periodic SIP revision, and would be used to illustrate: (1) The

amount of progress made since the last SIP revision, and (2) the amount

of progress made from the baseline period of the program.

Baseline Conditions

Proposed rule. The preamble to the proposal discussed an approach

for determining baseline visibility conditions for the haziest 20

percent and clearest 20 percent of days that would allow using a

minimum of 3 years of monitored data, and up to a maximum of 9 years of

data.

Comments received. The EPA received some comments suggesting that

it would be more equitable to use a standardized time period to

establish baseline values for all Class I areas across the country.

Other commenters supported the use of baseline values based on a

varying number of years from site to site. Some commenters also

supported the establishment of baseline conditions based on a period of

time longer than 3 years because a 3-year period could be significantly

influenced by unique meteorological circumstances.

Final rule. After considering public comments on the baseline

issue, EPA has determined that the most appropriate ``baseline period''

would be a fixed, 5-year period extending from calendar year 2000

through calendar year 2004. The EPA concluded that a standard baseline

period provides for greater national consistency in establishing this

important value, and therefore, is preferable to a provision allowing

the baseline period to be a variable number of years. Using a common

number of years and data points to calculate the baseline value for

each site is consistent with fundamental statistical principles and

will provide for easy comparison of data from multiple sites as the

program is implemented.

The EPA also concluded that it would be preferable to have a

baseline value based on more than 3 years in order to establish a more

robust baseline value. The EPA agrees with commenters that a 5-year

period, rather than a 3-year period, provides for a more stable

treatment of the inherent variability in emissions and meteorology.

This approach decreases the probability that the baseline period will

be unduly affected by unusual or nonrepresentative events.

In deciding upon the specific baseline period of 2000-2004, the

Agency took into account the fact that EPA has obtained funding to

provide several hundred monitors to the States for the purposes of

characterizing PM2.5 concentrations in urban and rural areas

nationally. In accordance with the part 58 monitoring provision

enabling IMPROVE protocol aerosol monitors to be used to characterize

PM2.5 conditions at background and transport sites, the

IMPROVE network will be expanding from 30 to more than 100 sites by the

end of 1999 in order to characterize both background PM2.5

levels and visibility impairment levels in Class I areas. Thus, EPA

concluded that the baseline period should begin in 2000, after

monitoring coverage for Class I areas is expanded significantly.

The approach to calculating baseline values will also provide for

more stable values because the frequency of monitoring samples in the

IMPROVE network will increase in 1999 to one sample every 3 days. In

this way, the frequency of sampling for IMPROVE will be consistent with

the PM2.5 monitoring approach. Thus, annual values should

become more robust since 17 percent more samples will be collected each

year. Baseline conditions must be determined in terms of deciviews for

the years 2000-2004 for the ``most impaired days'' and the ``least

impaired days.'' The final rule defines these values as the average of

the 20 percent of monitored days with the highest or lowest light

extinction values, expressed in deciviews. The EPA will issue guidance

for calculating baseline visibility conditions based on ambient

monitoring data. The baseline value is determined by calculating the

average deciview value for the 20 percent most (or least) impaired days

for each of the 5 years (2000 through 2004), and by averaging those

five values.

The final rule also calls for baseline conditions to be established

by the State for any Class I area without on-site monitoring by using

``representative'' monitoring data for the site. In the SIP, the State

will need to provide an adequate demonstration supporting the

[[Page 35729]]

use of any ``representative'' data. The EPA will issue guidance to help

the States address this issue. The IMPROVE Steering Committee

(comprised of representatives from EPA, States, and FLMs) is working to

develop acceptable criteria to configure the expanded visibility

monitoring network in such a way that virtually all Class I areas will

either have an aerosol monitor or will be characterized by a

``representative'' site. The IMPROVE Steering Committee, including

State representatives, will complete the process for identifying

representative sites before monitoring for the expanded network begins

in the year 2000. For this reason, it is expected that most States

needing to rely on representative data from another site will be able

to meet the requirement of section 51.308(d)(4) by referencing the

Visibility Monitoring Guidance Document, which will be released shortly

after promulgation of this rule, and other technical support materials

developed by the IMPROVE Steering Committee to support the

determination of representative sites.

Finally, States that submit SIPs for regional haze by 2003 under

section 51.309 (further discussion in unit IV) must determine baseline

conditions based on the most recent 5-year period for which monitoring

data are available for the Class I area. For an area without monitoring

data, the State may use data from another representative Class I area.

Natural Visibility Conditions

Proposal. The proposed rule called for each State having a Class I

area, in consultation with the appropriate FLMs, to: (1) Develop a

procedure to estimate natural conditions for the 20 percent most

impaired and least impaired days at each Class I area within the State;

and (2) provide this estimate with the State's first SIP revision for

regional haze (in the 2003-2005 timeframe as stated in the proposal).

The estimates for natural conditions would be expressed in deciviews.

The preamble cited as a default annual average, estimates of natural

visibility that were included in the 1991 NAPAP chapter on visibility.

When converted to deciview values, these annual average estimates are

9.6 deciviews in the Eastern United States and 5.3 deciviews in the

Western United States.

Comments received. A number of commenters noted that there are

several factors which can make the determination of natural conditions

difficult. For example, organic aerosols resulting from biogenic

sources, windblown dust, and natural causes of fire all contribute to

natural visibility conditions. Several commenters emphasized the

difficulty in determining the estimated contribution of naturally-

caused fire to natural conditions. Some commenters suggested that EPA

provide guidance on how to estimate natural conditions.

Final rule. The EPA understands that estimating natural visibility

conditions can involve many technically complex issues. The EPA is

committed to working with the States, tribes, and FLMs on this issue to

develop technical guidance on estimating natural visibility conditions.

The EPA expects that these estimates may be refined over time. In

addition, after the regional haze rule is promulgated, and in advance

of SIP due dates, EPA plans to revise the Interim Air Quality Policy on

Wildland and Prescribed Fires \74\ to address a number of issues,

including the contribution of fire to natural visibility conditions.

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\74\ Interim Air Quality Policy on Wildland and Prescribed

Fires, U.S. EPA, Office of Air Quality Planning and Standards, May

1998.

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Consistent with the proposal, the final rule retains the

requirement that each State provide an adequate estimate of natural

visibility conditions for best and worst visibility days in each Class

I area within the State. These estimates will be due at the time the

State submits its initial control strategy SIP for regional haze.

However, because the requirement for a SIP revision within 12 months of

promulgation has been overridden by the provisions of TEA-21, there no

longer is a requirement for States to separately submit to EPA

recommended procedures for estimating natural conditions in advance of

their control strategy SIPs.\75\

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\75\ See unit III.B. for a detailed discussion of the TEA-21

provisions and their affect on the timing for implementation of the

regional haze program.

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The EPA recommends that the States work closely with the FLMs,

tribes, and EPA in developing and documenting in their SIPs appropriate

methods for estimating natural conditions. Estimates of natural

visibility conditions are needed to aid all interested parties,

including the general public, in understanding how ``close'' or ``far''

a particular Class I area is in relation to the ultimate goal of the

program. Understanding the estimated relative contributions of natural

PM constituents (such as organic carbon and crustal material) also can

help the States and tribes in understanding the extent of the

contribution from manmade components, and thus can help in designing

appropriate emission management strategies in the future. With each

subsequent SIP revision, the estimates of natural conditions for each

Class I area may be reviewed and revised as appropriate as the

technical basis for estimates of natural conditions improve.

The EPA believes that, as a starting point, it will be appropriate

to derive regional estimates of natural visibility conditions by using

estimates of natural levels of visibility-impairing pollutants \76\ in

conjunction with the IMPROVE methodology for calculating light

extinction from measurements of the five main components of fine

particle mass (sulfate, nitrate, organic carbon, elemental carbon, and

crustal material). By using this approach with appropriate assumptions

for annual average relative humidity, EPA estimates natural conditions

for the worst visibility days to be approximately 11-12 deciviews in

the east and 8 deciviews in the west. The EPA supports use of these

estimating techniques as a valid starting point because they rely on

peer-reviewed estimates of the natural composition of fine particle

mass,\77\ and analysis of data from the IMPROVE program's well-

established approach, refined over the past 10 years or more, for

calculating light extinction from monitored PM constituents.

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\76\ See National Acid Precipitation Assessment Program. Acid

Deposition: State of Science and Technology. Report 24, Visibility:

Existing and Historical Conditions--Causes and Effects, Table 24-6.

Washington, DC. 1991.

\77\ The NAPAP estimates were cited in both the Criteria

Document and EPA Staff for the PM NAAQS.

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Because these values are expressed in regional terms only, further

refinement of these estimates will need to take place in the future on

a site-specific basis. However, because current conditions at most

Class I areas with existing IMPROVE monitoring exceed the above

estimates by at least several deciviews (with some of the more impaired

Class I areas having values that exceed estimated natural conditions by

20 deciviews or more), EPA does not believe that such refined values

are necessary for the initial 10-year program implementation period. As

the difference between current and natural conditions for a particular

Class I area becomes smaller, it will be important to develop more

precise techniques for estimating natural conditions.

Current Conditions

Proposal. The proposed rule required the State to revise its long-

term strategy every 3 years and to compare current conditions to the

visibility conditions existing at the time of its previous long-term

strategy revision. Current conditions would be established for the most

impaired and least impaired days, and would be expressed in deciviews.

[[Page 35730]]

Comments received. Many commenters supported EPA's approach to

periodic tracking of changes in visibility to determine reasonable

progress. Some commenters felt that averaging 5 years of data, rather

than 3, would be preferable.

Final rule. Section 51.308(f)(1) of the final rule retains the

requirement for each State, at the time of any SIP revision, to

determine the current visibility conditions for the most impaired and

least impaired days for each Class I area within the State. Current

conditions are to be based on the 5 most recent years of monitoring

data available at the time a SIP revision or progress report is

submitted. The approach for calculating current conditions is similar

to the approach for calculating baseline conditions discussed above:

the value is determined by calculating the average for the 20 percent

most impaired days for each of the 5 most recent years for which

quality-assured data are available, and then by calculating the average

of those five values.\78\

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\78\ See the section on Baseline Conditions for a discussion of

the rationale for selecting a 5-year period.

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Sections 51.308(f)(1) and 51.308(g)(3) of the final rule also

require the State to calculate the difference between current

conditions and several other parameters so that this information can be

taken into account when the State is revising its SIP and considering

new reasonable progress goals. A discussion of these calculations is

provided in unit III.J of this preamble addressing periodic SIP

revisions and progress reports.

Summary

The following summary table further illustrates the uses of

``baseline,'' ``natural,'' and current conditions in the regional haze

program.

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

How is it used in

Term What does it mean? the regional haze

program?

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

``Baseline conditions''..... Visibility (in ``Baseline''

deciviews) for the conditions are used

20 percent most- in two ways:

impaired days, and (1) For the first

for the 20 percent regional haze SIPs,

least-impaired due in about 2006-

days, for the years 2008, baseline

2000 through 2004. conditions are the

reference point

against which

visibility

improvement is

tracked.

(2) For subsequent

SIP updates (in the

year 2018 and every

10 years

thereafter),

baseline conditions

are used to

calculate progress

from the beginning

of the regional

haze program.

``Natural conditions''...... The level of ``Natural

visibility (in conditions''

deciviews) for the represents the

20 percent most- absence of

impaired days, and visibility

for the 20 percent impairment due to

least-impaired human-caused

days, that would emissions, the

exist if there were ultimate goal of

no manmade the regional haze

impairment.. program.

``Current conditions''...... ``Visibility (in For the initial

deciviews) for the planning SIPs,

20 percent most- ``current'' and

impaired days, and ``baseline''

for the 20 percent conditions are the

least-impaired same.

days, for the most For subsequent 5-

recent 5-year year progress

period. reports, ``current

conditions''

describe the amount

of progress that

has been made at

the mid-course

review point

halfway through an

implementation

cycle.

For subsequent

comprehensive

regional haze SIPs

(beginning in 2018

and every 10 years

thereafter),

``current

conditions'' will

be used to show how

much progress has

been made relative

to the

``baseline,'' and

will serve as the

reference point for

tracking progress

for the next

implementation

period.

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

F. Reasonable Progress Goals

The previous section discussed three important visibility

parameters for tracking ``reasonable progress'' toward the national

visibility goal. In this section, EPA describes the requirements of

section 51.308(d)(1) of the final rule for States to establish

``reasonable progress goals'' for each Class I area within the State.

In addition, this section also discusses important analyses and other

factors for States to take into consideration in setting these goals.

Proposed rule. In the proposed rule, EPA presented a framework for

a long-term program under which continued progress would be achieved in

Class I areas toward the national visibility goal. The EPA proposed

presumptive ``reasonable progress targets,'' expressed in terms of

deciviews, for the purposes of improving visibility on the 20 percent

worst days and allowing no degradation of visibility on the 20 percent

best days. Two options were presented for the presumptive target for

the most impaired days: (1) A rate of improvement equivalent to 1.0

deciview over a 10-year period, and (2) a rate of improvement

equivalent to 1.0 deciview over a 15-year period. For the least

impaired days, EPA proposed a target of no degradation, defined as less

than a 0.1 deciview increase.

The EPA noted that the 10- and 15-year time periods for tracking

improvement were consistent with section 169A(b)(2)(B), which calls for

States to develop long-term strategies covering 10 to 15 years. The EPA

also emphasized the importance of achieving a perceptible change in

visibility over the time period of a long-term strategy. In addition,

EPA stated that gradual improvements in visibility as defined by

reasonable progress targets were consistent with the GCVTC definition

of reasonable progress, which is ``achieving continuous emissions

necessary to reduce existing impairment and attain steady improvement

of visibility in mandatory Class I areas.

[[Page 35731]]

* * *'' 79 As noted in unit III.C., EPA also proposed to

track progress in relation to the targets through the use of monitored

air quality data and calculation of light extinction values from this

aerosol data.

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\79\ GCVTC Report, June 1996, p. x.

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The proposal also provided a process by which a State could

establish alternate reasonable progress targets, expressed in

deciviews, provided the State justified the alternate target based on a

review of the relevant statutory factors.80 These factors

are:

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\80\ See CA A section 169A(g)(1) and 169A(g)(2). See also 62 FR

41145-41148.

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The costs of compliance;

The time necessary for compliance;

The energy and nonair quality environmental impacts of

compliance; and

The remaining useful life of any existing source subject

to such requirements.

Comments received. A number of commenters advocated a faster rate

of improvement than the proposed presumptive rate of 1 deciview every

10 or 15 years since, as proposed, they claimed it could take more than

200 years to reach the national visibility goal in some eastern

locations. They felt that this rate of progress should not be

considered ``reasonable.'' Many of these commenters supported a rate of

improvement for the worst days equal to 10-20 percent of the current

deciview value (i.e., 3-6 deciviews per 10 years in an average eastern

location with a worst day value of 30 deciviews, and 1.5-3.0 deciviews

for an average southwestern location with a worst day value of 15

deciviews). A number of other commenters interpreted the proposed rule

as requiring an inflexible visibility ``standard'' of 1 deciview

improvement every 10 or 15 years. They maintained that such a standard

would be infeasible to achieve in some areas of the country, and that

EPA had failed to justify such a presumption through an analysis of the

statutory factors in section 169A(g). These commenters wanted the

States to have greater flexibility in setting visibility goals. Some

commenters stated that 1 deciview is not the threshold of perception in

all situations, and that for this reason the one deciview presumptive

target in the proposal should be dropped. Other commenters asserted

that the no degradation target for the best visibility days would

prevent new source growth in some areas. Some commenters also opposed

the presumptive target because of the concern that a State could be

subject to a citizen lawsuit for not meeting a reasonable progress

target.

Final rule. In considering how to address the reasonable progress

target issue in the final rule, EPA was mindful of the balance that

must be maintained between the need for strategies that will achieve

meaningful improvements in air quality and the need to provide

appropriate flexibility for States in designing strategies that are

responsive to both air quality and economic concerns. After considering

the comments on the ``presumptive target'' issue, EPA has revised the

rule to eliminate ``presumptive targets.'' There is no presumptive

target that States are required to meet to achieve reasonable progress.

States have flexibility in determining their reasonable progress goals

based on consideration of the statutory factors. However, as discussed

below, the final rule requires States to conduct certain analyses to

ensure that they consider the possibility of setting an ambitious

reasonable progress goal, one that is aimed at reaching natural

background conditions in 60 years.

The final rule calls for States to establish ``reasonable progress

goals,'' 81 expressed in deciviews, for each Class I area

for the purpose of improving visibility on the haziest days and not

allowing degradation on the clearest days over the period of each

implementation plan or revision. The EPA believes that requiring States

to establish such goals is consistent with section 169A of the CAA,

which gives EPA broad authority to establish regulations to ``ensure

reasonable progress,'' and with section 169B of the CAA, which calls

for EPA to establish ``criteria for measuring reasonable progress''

toward the national goal.

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\81\ See section 51.308(d)(1).

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This approach is designed to address the concerns of those

commenters interested in greater State flexibility in setting

visibility goals, as well as the concerns of those commenters who

believed that the presumptive 1 deciview target approach could actually

provide a disincentive for some States to pursue more ambitious rates

of progress, particularly for the most impaired Class I areas in the

East. The EPA has taken this approach in the final rule because the CAA

national visibility goal and ``reasonable progress'' provisions do not

mandate specific rates of progress, but instead call for ``reasonable

progress'' toward the ultimate goal of returning to natural background

conditions. Today's final rule requires the States to determine the

rate of progress for remedying existing impairment that is reasonable,

taking into consideration the statutory factors, and informed by input

from all stakeholders.

Required analysis of rate of progress which would attain natural

conditions in sixty years. The EPA received numerous comments

expressing the concern that a rate of progress that would result in

reaching the national goal in 200 years should not be considered

``reasonable.'' These comments are based on the fact that the most

impaired Eastern United States Class I areas have current conditions

for the worst days (around 26-31 deciviews) that exceed estimated

natural conditions (approximately 10-12 deciviews) by 16-20 deciviews

or more. At the proposed presumptive rate of progress of 1 deciview per

10 years, it would take 200 years or more to reach the national

visibility goal in many Eastern Class I areas. In addition, several

commenters felt that rates of progress should vary between the east and

the west because many parts of the western United States have much

lower levels of visibility impairment than the east. For example, they

asserted that a 1 deciview improvement over 10 years may not be very

ambitious in an eastern location, whereas it could be very ambitious in

some of the least impaired Class I areas in the west.

In order to address the diverse concerns of commenters on the

proposal, EPA is establishing an analytical requirement that takes into

account the varying levels of visibility impairment in Class I areas

around the country while ensuring an equitable approach nationwide. To

determine an equitable analytical approach, we considered the CAA

amendments of 1990, which require actions to attain air quality health

standards over a 20-year period for the 1-hour ozone standard,

depending on the severity of the area's problem, and over a 10-year

period for new standards, such as the new 8-hour ozone standard and the

PM2.5 standards. The CAA also requires reductions over the

same time period to address acid rain. In the eastern United States,

EPA's analyses show that the reductions from these and other CAA

programs will result in a rate of improvement estimated at

approximately 3 deciviews over the period from the mid-1990's to about

2005.82 The EPA calculated that if this rate of improvement

could be sustained, these areas would reach the national goal in 60

years.83 The EPA

[[Page 35732]]

concluded that it would be reasonable to establish an analytical

requirement based on this rate of progress given that this rate of

improvement is expected to be achieved due to emissions under CAA

programs.

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\82\ U.S. EPA, Effects of the 1990 Clean Air Act Amendments on

Visibility in Class I Areas: An EPA Report to Congress. Office of

Air Quality Planning and Standards, EPA-452/R-93-014, 1993.

\83\ Calculated by dividing 3 deciviews (per 10 years) into an

average of 18 deciviews away from natural conditions, and

multiplying 6 increments by 10 years, assuming 10 years to achieve

each increment.

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The EPA also believes that the analytical requirement of the rate

of improvement needed to reach natural conditions in 60 years is

reasonable because in the near-term, cost-effective controls will

continue to be available to reduce emissions that contribute to

visibility impairment in Class I areas across the country. Recent

analyses for other air quality programs show that significant emissions

can be achieved through cost-effective control measures.

In addition, in the longer term, it can be expected that continued

progress in visibility will be possible as industrial facilities built

in the latter half of the 20th century reach the end of their ``useful

lives'' and are retired and/or replaced by cleaner, more fuel-efficient

facilities. Significant improvements in pollution prevention

techniques, emissions control technologies, and renewable energy have

been made over the past 30 years, and continue to be made. History

strongly suggests that further innovations in control technologies are

likely to continue in future decades, leading to the ability of new

plants to meet lower emissions rates.

In light of this analysis of progress that could potentially be

achieved, EPA has established in section 51.308(d)(1)(i)(B) an

analytical requirement for setting reasonable progress goals that

should provide for greater equity between goals set for the more

impaired Eastern United States and the less impaired Western United

States. This analytical requirement has the following four steps.

First, the State (or regional planning group) must compare the

baseline visibility conditions in the years 2000-2004 (in deciviews)

for the most impaired days with the natural background conditions, for

each relevant Class I area. From this comparison, the State must

determine the amount of progress needed to reach natural background

conditions in 60 years, that is, by the year 2064. For example, if the

baseline visibility is 30 deciviews, and the natural background is 12

deciviews, then this step would show the need for an 18 deciview

improvement between 2004 and 2064.

Second, the State must identify the uniform rate of progress over

the 60 year period that would be needed to attain natural background

conditions by the year 2064. For the example case noted above, where 18

deciviews is the amount for the 60-year period, this would result in a

uniform rate of progress for each year of (18/60), or 0.3 deciviews for

a year.

Third, the State must identify the amount of progress that would

result if this uniform rate of progress were achieved during the period

of the first regional haze implementation plan. For example, if the

first implementation plan covers a 10-year period, then for the above

example, the State would identify a 3 deciview amount of progress over

that time period.

Fourth, the State must identify and analyze the emissions measures

that would be needed to achieve this amount of progress during the

period covered by the first long-term strategy, and to determine

whether those measures are reasonable based on the statutory factors.

These factors are the costs of compliance with the measures, the time

necessary for compliance with the measures, the energy and nonair

quality environmental impacts of the compliance with the measures, and

the remaining useful life of any existing source subject to the

measures.

In doing this analysis, the State must consult with other States

which are anticipated to contribute to visibility impairment in the

Class I area under consideration. Because haze is a regional problem,

States are encouraged to work together to develop acceptable approaches

for addressing visibility problems to which they jointly contribute. If

a contributing State cannot agree with the State establishing the

reasonable progress goal, the State setting the goal must describe the

actions taken to resolve the disagreement.

If the State determines that the amount of progress identified

through the analysis is reasonable based upon the statutory factors,

the State should identify this amount of progress as its reasonable

progress goal for the first long-term strategy, unless it determines

that additional progress beyond this amount is also reasonable. If the

State determines that additional progress is reasonable based on the

statutory factors, the State should adopt that amount of progress as

its goal for the first long-term strategy.

If the State determines, based on the statutory factors, that the

identified uniform rate of progress needed to reach natural conditions

is not reasonable, the State must provide in its plan submission the

analysis and rationale supporting this determination. The State then

must provide a demonstration as part of its SIP submission showing why

a less ambitious goal is reasonable, based on the statutory factors.

The EPA intends to issue guidance interpreting the statutory factors

and providing examples of ways in which they may be applied.

The State must also provide to the public, in accordance with

section 51.308(d)(1)(ii), an assessment of the number of years it would

take to reach natural conditions if the State continued to make

progress at the alternative rate of progress it selected. For example,

if average worst day visibility at the class I area is 18 deciviews

from estimated natural conditions, the uniform rate of progress needed

to reach natural conditions is 3 deciviews per 10 years. If the State

determined that 3 deciviews is not reasonable but 2 deciviews is, then

the State would have to include a statement in its SIP that it would

take 90 years to reach natural conditions if this rate is maintained.

It should be noted that in developing the first regional haze

implementation plan (and subsequent revisions), there is a time period

of several years between the time period for which data are available

and the date of plan submission. The first regional haze implementation

plans for most of the United States will use the years 2000 through

2004 as the baseline for monitoring and emission inventories, while the

first implementation plan for much of the country will not be due until

a deadline that occurs between 2006 to 2008. In identifying the amount

of progress needed by the end of the implementation period (the third

step described above), States must account for this time period.

Assume, for example, for the case discussed above (i.e., a 30 deciview

baseline, and a uniform rate of progress of 0.3 deciviews per year to

reach natural conditions in 60 years) that the first regional haze SIPs

covers the years 2009 through the year 2018. For this case, there would

thus be a 4-year period (2005 through 2008) that would occur between

the baseline and the date of SIP submission. The uniform rate of

progress of 0.3 deciviews per year over this time period would result

in 1.2 deciviews of improvement before the plan submission. Hence, for

this example, in identifying the amount of progress needed between the

baseline and the end of the implementation period (i.e., the year

2018), the State must evaluate strategies that provide for a total of

4.2 deciviews: 1.2 deciviews between the last year of the baseline

period and plan submission, and 3 deciviews for the implementation

[[Page 35733]]

period. The effect of this provision is that States must be mindful of

the expected activities that take place before plan submission.

Generally, we expect for the first plan submission period that progress

in visibility improvement will continue to occur during the 2004 to

2008 period due to implementation of other CAA programs.

Rationale for the required 60-year analysis. The EPA has adopted

this analytical requirement for two reasons. First, a common analytical

framework that recognizes regional differences meets the concerns of

several commenters by providing greater equity between the Eastern

United States and Western United States.

Second, EPA believes this analysis will provide important

additional information for the public to consider as States establish

progress goals. The EPA believes this analysis will provide for a more

informed and equitable decision making process by giving the public

information about the level of emissions needed, related costs, and

other factors associated with improvements in visibility. The EPA

recommends that as part of this process, the States use computer-based

scene optics modeling tools to present to the general public the

anticipated change in Class I area visibility that would result from

one reasonable progress goal versus another.

Consideration of other CAA measures. In determining the emissions

and visibility improvement achieved during each implementation period,

States should include all air quality improvements that will be

achieved by other programs and activities under the CAA and any State

air pollution control requirements. Therefore, any reasonable progress

goal for a Class I area should reflect at least the rate of visibility

improvement expected from the implementation of other ``applicable

requirements'' under the CAA during the period covered by the long-term

strategy. Consequently, States must take into account, at a minimum,

the effect of measures to meet the NAAQS, the national mobile source

program, and other applicable requirements under the CAA on Class I

area visibility.

While, as noted above, based on our current understanding, EPA

expects in the eastern United States that the reductions from measures

implementing the CAA requirements will provide the visibility

improvement and emissions needed for reasonable progress during the

first regional haze implementation plan, EPA also recognizes that

States will not be submitting their regional haze plans for several

years. In developing its submittal, each State will need to conduct

analyses to support its reasonable progress goals according to

information available at the time the plan is submitted about benefits

from the existing CAA programs. Each State should set its goal(s)

taking into consideration input from its stakeholders and based on the

statutory factors described above. In addition, the State must also

conduct a BART determination for each source subject to BART as

required in section 51.308(e) of the rule and described in section

III.H. of the preamble. In considering whether reasonable progress will

continue to be maintained, States will need to consider during each new

SIP revision cycle whether additional control measures for improving

visibility may be needed to make reasonable progress based on the

statutory factors.

Some commenters expressed concern that the State would be subject

to sanctions or enforcement actions in the event that a State fails to

meet a reasonable progress target. As noted above, the reasonable

progress goal is a goal and not a mandatory standard which must be

achieved by a particular date as is the case with the NAAQS. Once a

State has adopted a reasonable progress goal and determined what

progress will be made toward that goal over a 10-year period, the goal

itself is not enforceable. All that is ``enforceable'' is the set of

control measures which the State has adopted to meet that goal. If the

State's strategies have been implemented but the State has not met its

reasonable progress goal, the State could either: (1) revise its

strategies in the SIP for the next long-term strategy period to meet

its goal, or (2) revise the reasonable progress goals for the next

implementation period. In either case, the State would be required to

base its decisions on appropriate analyses of the statutory factors

included in section 51.308(d)(1)(i)(A) and (B) of the final rule.

If a State fails to submit an approvable SIP, or if it fails to

implement and enforce strategies adopted into its SIP, the State could

be subject to sanctions under the CAA. If the State continues to fail

in meeting its obligations, EPA could be required to develop and

implement a Federal implementation plan (FIP).

Allowing no degradation for the best days. Some commenters

supported the goal of no degradation at a minimum, but they asserted

that in many Class I areas, particularly in the east, the ``best days''

are in fact still quite impaired. In their view, a rule requiring only

preservation of existing clean days would not meet the national

goal.84 Other commenters stated that a ``no degradation''

target for the clearest days could result in limitations to economic

growth.

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\84\ Data from the IMPROVE network show that for several sites

in the Eastern United States, the deciview values for the best days

are greater than 14 deciviews, which is higher than even the NAPAP

estimate of annual average conditions in the Eastern United States

(9.6 deciviews).

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The final rule maintains the approach used in the proposed rule,

which established a goal of no degradation for the best visibility

days. The EPA believes this approach is consistent with the national

goal in that it is designed to prevent future impairment, a fundamental

concept of section 169A of the CAA. The EPA recognizes that the best

days are still impaired in many Class I area locations, particularly in

the east. The EPA encourages States to evaluate monitoring data to

determine whether the same types of sources are affecting both the

clear days and the hazy days. If the relative contribution of different

particle types to light extinction is similar for both clear and hazy

days, as it is for many sites currently monitored, then by developing

strategies to improve conditions on the worst visibility days, the

States will likely improve the entire distribution of hazy and clear

days. Thus, under the final rule, the clean days for most Class I areas

are expected to improve over time. Indeed, recent analyses of

visibility trends have shown that at many Class I areas, deciview

values for the 20 percent least impaired days are declining.

If at a Class I area the average conditions for clear days degrades

over time, the State must provide in the next plan revision an

explanation of why this happened, a set of measures designed to reverse

this trend, and a plan for implementation during the next 10-year

period. The State should review the effectiveness of these measures in

subsequent 5-year progress reviews.

Integral vistas. The scenic vistas enjoyed by visitors to many

parks often extend to important natural features outside these parks.

The 1980 rules included a provision whereby the States could identify

specific vistas for protection. For this reason, EPA solicited comment

on whether the integral vistas concept should be extended to the

regional haze program.

Some commenters supported reopening the vista identification

program because such vistas are a significant resource of a Class I

area. Several others opposed extending the program for a variety of

reasons.

[[Page 35734]]

The final regional haze rule does not extend the integral vista

concept to the regional haze program. As noted earlier in the

background section of this preamble, regional haze is caused by a

multitude of sources across a broad geographic area, and it can create

a uniform haze in all directions. The regional haze program is designed

to bring about improvements in regional visibility for the range of

possible views of sky and terrain found in any Class I area.

Accordingly, the program does not protect only specific views from a

Class I area. To address haze, regional strategies will be needed, and

emissions resulting from these strategies are expected to improve

visibility across a broad region, not just within a Class I area. Thus,

although the regional haze program does not include a specific

provision regarding integral vistas, the long-term strategies developed

to meet reasonable progress goals would also serve to improve scenic

vistas viewed from and within Class I areas.

Use of 20 percent most-impaired days and 20 percent least-impaired

days. The final rule maintains the approach discussed in the proposal

of improving the most-impaired visibility days (i.e., the average of

the 20 percent most impaired days over an entire year), and allowing no

degradation in the ``cleanest'' or least impaired days (i.e., the

average of the 20 percent least impaired days over an entire year). In

deciding upon an appropriate characterization of the ``most'' and

``least'' impaired days, EPA considered the typical frequency of

aerosol monitoring in the IMPROVE network 85 (once every 3

days), and the number of samples that would be available for analysis

annually (122 possible samples per year). The EPA believes that

calculating annual ``best'' and ``worst'' conditions on the basis of an

average of the 20 percent best and worst visibility days represents a

reasonable approach to characterizing the typical best and worst

conditions without having these values unduly influenced by a single

anomalous data point.

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\85\ The IMPROVE network is described in unit III.I. of the

preamble.

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The EPA's basis for maintaining the proposed approach is supported

by the CAA and its legislative history, and by the approach used by the

GCVTC in its technical assessment work and in its definition of

reasonable progress. The EPA believes that a rule that requires

strategies for improving the worst days and allowing no degradation on

the clean days is consistent with the national visibility goal in

section 169A of the CAA, which calls for preventing any future

impairment (protecting clearest days) and remedying any existing

impairment (improving the already impaired days). This approach is also

supported by the legislative history of the 1990 CAA and the reasonable

progress definition. The legislative history provides that, ``At a

minimum, progress and improvement must require that visibility be

perceptibly improved compared to periods of impairment, and that it not

be degraded or impaired during conditions that historically contribute

to relatively unimpaired visibility.'' 86 The GCVTC

interpreted ``reasonable progress'' to be ``achieving continuous

emissions reductions necessary to reduce existing impairment and attain

a steady improvement in visibility in mandatory Class I areas, and

managing emissions growth so as to prevent perceptible degradation of

clear air days.'' 87 In today's final rule, EPA is similarly

providing for ``attaining a steady improvement in visibility'' and

``preventing degradation of clean air days'' through the requirement to

improve the haziest days and prevent degradation of the clearest days.

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\86\ 136 Cong. Rec. S2878 (daily ed. March 21, 1990) (statement

of Sen. Adams).

\87\ GCVTC Report, p. x.

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Tracking progress based on 5-year averages. To determine whether

reasonable progress in improving visibility is being achieved, States

will need to collect and analyze air quality data each year and review

progress at 5-year intervals. Because the regional haze program

represents a long-term effort to improve visibility in Class I areas,

EPA believes that monitoring and assessments of progress should not be

unduly influenced by short-term events or unusual meteorological

conditions, but should reflect trends in air quality which are robust

and insensitive to minor fluctuations. For this reason, the final rule

calls for measuring progress by tracking changes in 5-year average

deciview values for the haziest and clearest days, and comparing these

current conditions against baseline conditions as well as impairment

levels at the time of the last SIP revision. (See unit III.E above for

further discussion about establishing baseline and current conditions

based on 5-year averages.)

G. Long-Term Strategy

Proposed rule. Under Section 169A(b)(2) of the CAA, EPA's

visibility regulations must require States to include in their SIPs

``such emission limitations schedules of compliance and other measures

as may be necessary to make reasonable progress toward meeting the

national goal specified in * * * [section 169A(a)] * * *'' In section

169A(b)(2)(B), the CAA requires that these SIPs must include a ``long-

term (ten to fifteen years) strategy for making reasonable progress

toward meeting the national goal.'' The EPA interprets the term ``long-

term strategy'' as the control measures that are needed to ensure

reasonable progress, together with a demonstration that those measures

will provide for reasonable progress during the 10 to 15 year period.

The proposed rule required the State to develop a long-term strategy

for regional haze with the initial regional haze SIP

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