v»EPA
United States
EnvimnmiMital Protection
icy
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
June 1980
An
Visibility Protection
Proposed Regulations
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NEED TO PRESERVE Millions of Americans each year travel thousands of miles to
BEAUTY OF PARKS experience firsthand this country’s most unspoiled heritage--its
LONG RECOGNIZED national parks and wilderness areas. Americans have long recognized
AS IMPORTANT the need to preserve and enhance the majestic beauties of this heri-
tage. Congress in 1916 passed the National Park Service Act, thus
creating a nationwide park service to ‘conserve the scenery and the
natural (objects) and provide for the enjoyment of the same in
such manner. . . as will leave them unimpaired.” Almost half a
century later, the Wilderness Act received approvals providing
for the preservation of any such area.
POLLUTION A THREAT But in recent years air pollution -- spawned by rapid energy develop-
TO SCENIC APPEAL ment and industrialization —- is threatening the scenic value
OF LANDSCAPES of park and wilderness lands. Congress addressed this problem in
its 1977 Clean Air Act Amendments, and incorporated provisions for
cleaning up and preventing dirty air in regions where the natural
beauty of landscapes must be protected.
CLEAN AIR ACT The Clean Air Act authorizes the U.S. Environmental Protection
CALLS FOR Agency (EPA) to explore the effects of man-made air pollution on
VISIBILITY visibility problem. On May 22, 1980 (44FR34762) , EPA proposed an
PROTECTION initial regulatory program for safeguarding over 29 million acres
of national park and wilderness areas. The program complies with
Section 169A of the Act, which requires regulations to prevent any
future, and remedy any existing “visibility impairment” in these
areas caused by air pollution.
Specifically, visibility protection is required for all mandatory
class I Federal areas where the visual quality of the ambient air
is important. All international parks, national wilderness areas,
and national memorial parks larger than 5,000 acres, as well as
all national memorial parks larger than 6,000 acres, comprise
mandatory class I Federal areas. Following recomendations from
the U.S. Department of Agriculture, and the Department of the
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Interior, EPA identified 156 class I areas as regions where visv
bility must be protected from the air pollution that produces
visibility impairment.
POOR VISIBILITY
CAUSED BY PARTICLES
THAT SCATTER OR
ABSORB LIGHT
Visibility impairment, as defined by EPA, is any perceptible change
in visibility (including visual range, contrast, or atmospheric
color) from what would have existed under natural conditions.
Poor visibility is caused when fine solids or liquid aerosols --
usually in the form of primary particulates, nitrogen oxides, or
sulfur oxides -- absorb or scatter light. This light scattering
or absorption actually reduces the amount of light received from
"viewed objects," and in addition, scatters light into, or out of,
an observer's line of vision.
HAZE, PLUMES
MAJOR TYPES
OF IMPAIRMENT
Two categories of visibility impairment have been identified —
haze and plume blight. The polluted air masses that contribute to
haze often stretch hundreds of miles and linger for long periods
of time. Haze discolors the surrounding air and, more importantly,
degrades the aesthetic appeal of landscapes by causing objects to
appear flattened, and the horizon sky whitened, so that textures
and colors are obscured to varying degrees. Plume blight results
when particles and light-absorbing gases are confined to a single
plume of air pollution. Consisting of white, gray, or brown
plumes that can be easily discerned against the sky (or other
background objects), plume blight usually can be traced to one
source or a small group of sources.
Air pollution that contributes to haze and plume blight can be
traced to several industrial or other man-made sources. Among
these are:
t utilities
• industrial fuel combustion
• smelters
• pulp mills
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• urban plumes (from point sources, space heating,
mobile and other industrial sources)
• fugitive dust from agricultural activities, mining,
and unpaved roads
• managed use of fires
EPA PROPOSES Although deterioration of visual quality is one of air pollution’s
“PHASED APPROACH” most obvious effects, and is the best understood at this time,
TO PROBLEM technical and scientific limitations remain. Recognizing these
limitations -- but recognizing also that visibility protection
must be initiated as soon as possible -- EPA has proposed what it
terms a phased approach to this unique pollution problem.
After extensive review of techniques for identifying, measuring,
and controlling visibility impairment, EPA determined that current
modeling and monitoring techniques require further evaluation before
they can be required as a routine part of a visibility protection
program. However, sophisticated analytical techniques are un-
necessary in identifying the origins of visibility impairment from
a single source, or group of sources (which Phase I will address).
Visual observations, (ground-based or from aircraft) or other
simple monitoring techniques, can help identify sources whose
pollution contributes to visibility impairment. Modeling and
monitoring techniques used in analyzing impairment from single
sources should be available soon, while similar techniques for
complex, multiple-source problems (regional haze and urban plumes)
need more research, and thus will be unavailable for some time.
PHASE I SETS UP EPA’s phased approach reflects the varying levels of scientific
INITIAL STRATEGIES knowledge in the visibility problem. The Agency’s proposed
FOR VISIBILITY regulations outline Phase I of the visibility protection program,
PROTECTION which would:
Require controls for certain single sources or groups of
sources as contributors to visibility-degrading pollution.
State agencies, in cooperation with the Department of the
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Interior, and the Department of Agriculture (Federal Land
Managers) will analyze existing industrial sources and,
where necessary, require BART installation for sources
whose emission affect visibility. In Phase I, retrofit
controls are expected for only a limited number of sources.
Evaluate and control new sources to prevent future visi-
bility impairment. Visibility protection regulations
outlined in Section 1691\ of the Clean Air Act are also
addressed in Section 165 of the Act, which outlines PSD
regulations. PSD (prevention of significant air quality
deterioration) regulations require that planned industrial
facilities, or facilities planning major modifications, be
evaluated for potential visibility impacts. If it is deter-
mined that a source would adversely affect visibility in
class I areas, then a state must deny the required construc-
tion permit.
Require states to adopt other strategies for remedying
existing, and preventing future, visibility impairment.
States containing class I areas targeted for visibility
protection must revise their State Impementation Plans
(SIPs) to include long—term strategies for making reasonable
progress toward the visibility goal. For example, states
could consider measures such as smoke management techniques,
and sources retirement and replacement schedules.
EPA’s initial visibility program will have a significant impact
on Western regions, since visibility in these areas is especially
sensitive to degradation from pollution. In addition, the majority
of class I areas are located in the West. Subsequent phases
will focus on regional haze and urban plume controls.
STATES REQUIRED The 36 states that contain mandatory class I Federal areas
TO SUBMIT targeted for visibility protection must, within 9 months of
SIP REVISIONS the final promulgation of these rules, revise and submit to
EPA State Implementation Plans that reflect the measures out-
lined above. Guidelines will be provided by EPA to assist
states with their SIP revisions.
PUBLIC HEARINGS EPA is soliciting input from various state and local air pollution
SCHEDULED control agencies, from industrial groups, and from other public
and private sectors. A 75-day comment period has been established
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to allow public comment on the proposed regulation. Two
public hearings, also designed to solicit public input on
the regulations, have been scheduled. The first public
hearing will be held June 30, 1980, at the EPA Building,
Room 3906 Waterside Mall, 401 M Street SW, Washington, D.C.
The second hearing is scheduled for July 2, 1980, at the
Salt Palace, 100 SW Temple Street, Salt Lake City, Utah.
Both hearings will begin at 9 a.m.
All written comments on the proposed visibility regulations should
be submitted to: Central Docket Section (a-l30), Docket No. A-79—40,
U.S. Environmental Protection Agency, 401 M Street SW, Washington,
D.C. 20460. The docket contains all materials relevant to the
regulation, and is open for public inspections.
Further information on this regulatory action may be obtained
from Johnnie Pearson or Julie Home, Office of Air Quality
Planning and Standards, EPA, Research Triangle Park, N.C. 27711,
telephone (919) 541-5497.
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