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What is regional
Haze consists of sufficient smoke, dust, moisture, and vapor sus-
pended In air to impair visibility. The term "regional haze" means
haze that impairs visibility in all directions over a large area.
How is regional fmze formed?
Haze is caused by particulate matter from many sources — includ-
ing smoke, road dust, and other particles emitted directly into the
atmosphere, as well as particulate matter formed when gaseous
pollutants react in the atmosphere. These particles«ften grow in
size as humidity increases, further impairing visibility. Sources
hundreds or even thousands of miles away can contribute to vis-
ibility problems at remote locations, such as national parks.
H©w does regional affect
Visibility often is measured as the farthest distance from which a
person can see a landscape feature. Haze currently reduces nat-
ural visibility from 90 miles to between 14 and 24 miles in the
eastern United States, and from 1 40 miles to between 33 and 90
miles in the western United States. Visibility generally is worse in
the eastern United States due to higher average humidity levels
and higher levels of particulate matter from manmade and natur-
al sources.
While reviewing the ozone and particulate matter standards, EPA
has been working with stakeholders to draft implementation
guidance for states to follow in developing plans (called State
Implementation Plans) in the event that new standards are
adopted. Because ozone and particulate matter share many
characteristics (see above), EPA guidance will encourage and sup-
port integrated implementation of the ozone, particulate matter,
and regional haze programs so that emissions of ozone-forming
pollutants and fine particles can be reduced as cost-effectively, effi-
ciently, and flexibly as possible. This will help to reduce the burden
on the affected sources and state and local control agencies.
Many different groups would be affected by these standards and
the regional haze program. These "stakeholders" include state,
local, and tribal agencies, environmental and health groups,
industry, academia, and other federal agencies. EPA established
an advisory committee of these stakeholders in August 1995 to
obtain their input, ideas, and advice on innovative and effective
approaches to implementation. Based on this committee's rec-
ommendations, EPA is developing a two-phase, integrated
implementation strategy for the ozone, particulate matter, and
regional haze programs.
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How does particulate matter affect
health?
Both coarse and fine particles are of health concern because they
can penetrate into the sensitive regions of the respiratory tract.
Fine particles are of greatest concern because they are linked to
the most serious effects. They can cause persistent coughs,
phlegm, wheezing, and physical discomfort.
Several recently published
community health studies
indicate that significant
respiratory and cardiovas-
cular-related problems are
associated with exposure
to particle levgls well below
the existing particulate
matter standards. These
negative effects include
premature death, hospital
admissions from respiratory
causes, and increased respi-
ratory symptoms. Long-
term exposure to particulate
matter may increase the rate
of respiratory and cardiovas-
cular illness and reduce life
span.
LATE MATTER
LEMS
Children »t Risk
School and Woifcdaya
Mlaaad
Who is most at risk from participate
Children, the elderly, and individuals with cardiovascular disease
or lung diseases such as emphysema and asthma are especially
vulnerable.
How matter affect
the environment?
Fine particles can soil manmade materials, speed their deteriora-
tion, and impair visibility.
Refineries/Chemical Plants
NOY&VOCs
A
Cars
Trucks, Buses, and
Nonroad Equipment:
Power Plants
NOx&VOCs
Factories
VOCs = volatile organic
compound gases
PM = particulate matter
NOX = nitrogen oxide
SOj = sulfur dioxide
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he quality of the air we breathe
directly affects pur health and well-
being. For this reason, preserving air
quality has been a strong national priority since 1970,
when Congress*passed the Clean Air Act. Under this
authority, the U.S. Environmental Protection Agency (EPA)
has established a wide variety of standards and programs
to protect public health, the environment, and the quality
of life from the detrimental effects of air pollution.
Air quality standards—known as National Ambient Air Quality
Standards—set national goals for acceptable concentrations of
specific pollutants in outdoor air that:
• Threaten public health and the environment across broad
regions of the country.
0 Are emitted in relatively large quantities by a variety of
sources.
EPA has established air quality standards for six pollutants or
classes of pollutants—including ground-level ozone and particu-
late matter.
Newspapers and other media use monitoring data to give the
public regular updates comparing their local air quality to these
national stapdards.
So important are these standards to ensuring air quality that the
Clean Air Act requires EPA to review them at least every five years.
During these reviews, EPA examines all relevant scientific informa-
tion—especially new information since the last review—to deter-
mine whether the standards protect public health.
EPA recently reviewed the current air quality standards for
ground-level ozone (commonly known as smog) and particulate
matter (or PM). Based on new scientific evidence, EPA has pro-
posed revisions to both standards. At the same time, EPA is
developing a new program to control regional haze, which is
largely caused by particulate matter. This brochure describes why
ozone, particulate matter, and regional haze are a concern to
public health and the environment and provides information on
how any revised standards will be implemented.
Is ozone?
In the upper atmosphere, ozone occurs naturally and protects us
from the sun's ultraviolet radiation. At ground level, ozone results
from pollution and can harm our health. Ground-level ozone is
the primary ingredient of smog in our cities.
IFfow Is §r©ynd=level ozone formed?
Ground-level ozone forms when other pollutants—nitrogen
oxide and volatile organic compound gases—react with sunlight.
Sources for these pollutants include motor vehicles, power plants,
factories, chemical solvents, combustion products from various
fuels, and consumer products.
How does ®s®n<& affect health?
Ozone can impair people's ability to
breathe and cause shortness of
breath, chest pain, wheezing, and
coughing. People with respiratory
problems are most vulnerable, but
even some healthy people can be
affected while engaging in moder-
ate physical activity when ozone
levels are high enough. Animal
studies suggest that repeated
exposure to high levels of ozone
over several months may perma-
nently damage the lungs and
cause chronic respiratory illness.
Who Is molt at risk from ozone
pollution?
Scientific studies indicate that three groups are at particular risk
from high ozone levels:
• Children at play outdoors. Because their respiratory systems
are not fully developed, children are more susceptible to
ozone.
9 Healthy adults who exert themselves outdoors (such as
construction workers and road maintenance crews). Even
relatively low amounts of ozone can impair the ability of
healthy people to breathe during moderate exercise. Ozone
levels generally are highest during the summer months,
when people tend to spend the most time outdoors.
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• People with existing lung disease (including chronic bron-
chitis, emphysema, and asthma). Since they already suffer
from reduced ability to breathe, these individuals are often
greatly affected by the increased impairment that can result
from exposure to ozone.
In 1995, approximately 70 million U.S. residents were living in coun-
ties with ozone levels that exceed EPA's current ozone standard.
H©w does ozone affect the.
environment?
Ground-level ozone can have several environmental impacts:
• Ozone impairs the ability of plants to produce and store
food. This inhibits plant growth and reproduction and
diminishes plant health, which, in turn, weakens the ability
of plants to survive disease, insect attacks, and extreme
weather.
• Ozone can reduce agricultural yields and damage econom-
ically important crops—including soybeans, kidney beans,
wheat, and cotton.
Ozone can have long-te'rm impacts on forests and ecosys-
tems—including disruption "of ecological functions (such as
water movement and mineral nutrient cycling) and adverse
impacts on the natural habitats of plants and animals.
What is partleylate matter?
Particulate matter consists of the solid particles and liquid droplets
found in the air. Individually, these particles and droplets are invis-
ible to the naked eye. Collectively, however, they can appear as
clouds or a fog-like haze.
How Is participate matter formed?
Particulate matter less than 2.5 microns in diameter is referred to
as "fine" particles. (In comparison, a human hair is about 70
microns in diameter.) Fine particles result from many different
sources—including industrial and residential combustion and
vehicle, exhaust—so their composition varies widely. Fine particles
can also be formed when combustion gases are chemically trans-
formed into particles.
Particulate matter larger than 2.5 microns in diameter is referred to
as "coarse" particles. Coarse particles have many sources, includ-
ing wind-blown dust, vehicles traveling on unpaved roads, materi-
als handling, and crushing and grinding operations.
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One Congress Street
John F. Kennedy Federal Building
Boston, MA 02203-0001
(617)565-3420
290 Broadway
New York, NY 10007-1866
(212)637-3000
Region ill
841 Chestnut Building
Philadelphia, PA 19107
(215)566-5000
100 Alabama Street, SW
Atlanta, GA 30303
(404) 562-«357
77 West Jackson Boulevard
Chicago, IL 60604-3507
(312)353-2000
Hegloi? vi
Fountain Place, 12th Floor, Suite 1200
1445 Ross Avenue
Dallas, TX 75202-2733
(214)665-6444
Region VI!
726 Minnesota Avenue.
Kansas City, KS 66101
(913)551-7000
999 18th Street, Suite 500
Denver, CO 80202-2466
(303)312-6312
IX
75 Hawthorne Street
San Francisco, CA 94105
(415)744-1305
Region X
1200 Sixth Avenue
Seattle, WA 981 01
(206)553-1200
M
ore information about ozone and
particulate matter and related programs
can be found on the Internet at EPA's Office of Air
Quality Planning and Standards home page:
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