Airborne particles, the main ingredient of haze, smoke, and
airborne dust, present serious air quality problems in many areas
of the United States. This particle pollution can occur year-round—and
it can cause a number of serious health problems, even at concentrations
found in many major cities.
What is particle pollution?
Particle pollution is a mixture of microscopic solids and liquid
droplets suspended in air. This pollution, also known as particulate
matter, is made up of a number of components, including acids (such
as nitrates and sulfates), organic chemicals, metals, soil or dust
particles, and allergens (such as fragments of pollen or mold spores).
The size of particles is directly linked to their potential for
causing health problems. Small particles less than 10 micrometers
in diameter pose the greatest problems, because they can get deep
into your lungs, and some may even get into your bloodstream. Exposure
to such particles can affect both your lungs and your heart. Larger
particles are of less concern, although they can irritate your eyes,
nose, and throat.
Small particles of concern include "fine particles" (such
as those found in smoke and haze), which are 2.5 micrometers in
diameter or less; and "coarse particles" (such as those
found in wind-blown dust), which have diameters between 2.5 and
10 micrometers.
Are you at risk from particles?
People with heart or lung disease, older adults, and children are
considered at greater risk from particles than other people, especially
when they are physically active. Exercise and physical activity
cause people to breathe faster and more deeply—and to take
more particles into their lungs.
People
with heart or lung diseases—such as coronary artery
disease, congestive heart failure, and asthma or chronic obstructive
pulmonary disease (COPD)—are at increased risk, because particles
can aggravate these diseases. People with diabetes also may be at
increased risk, possibly because they are more likely to have underlying
cardiovascular disease.
Older adults are at increased risk, possibly because
they may have undiagnosed heart or lung disease or diabetes. Many
studies show that when particle levels are high, older adults are
more likely to be hospitalized, and some may die of aggravated heart
or lung disease.
Children are likely at increased risk for several
reasons. Their lungs are still developing; they spend more time
at high activity levels; and they are more likely to have asthma
or acute respiratory diseases, which can be aggravated when particle
levels are high.
It appears that risk varies throughout a lifetime, generally being
higher in early childhood, lower in healthy adolescents and younger
adults, and increasing in middle age through old age as the incidence
of heart and lung disease and diabetes increases. Factors that increase
your risk of heart attack, such as high blood pressure or elevated
cholesterol levels, also may increase your risk from particles.
In addition, scientists are evaluating new studies that suggest
that exposure to high particle levels may also be associated with
low birth weight in infants, pre-term deliveries, and possibly fetal
and infant deaths.
How can particles affect your health?
Particle exposure can lead to a variety of health effects. For
example, numerous studies link particle levels to increased hospital
admissions and emergency room visits—and even to death from
heart or lung diseases. Both long- and short-term particle exposures
have been linked to health problems.
Long-term exposures, such as those experienced
by people living for many years in areas with high particle levels,
have been associated with problems such as reduced lung function
and the development of chronic bronchitis—and even premature
death.
Short-term exposures to particles
(hours or days) can aggravate lung disease, causing asthma attacks
and acute bronchitis, and may also increase susceptibility to respiratory
infections. In people with heart disease, short-term exposures have
been linked to heart attacks and arrhythmias. Healthy children and
adults have not been reported to suffer serious effects from short-term
exposures, although they may experience temporary minor irritation
when particle levels are elevated.
What
are the symptoms of particle exposure?
Even if you are healthy, you may experience temporary symptoms,
such as irritation of the eyes, nose, and throat; coughing; phlegm;
chest tightness; and shortness of breath.
If you have lung disease, you may not be able
to breathe as deeply or as vigorously as normal, and you may experience
coughing, chest discomfort, wheezing, shortness of breath, and unusual
fatigue. If you have any of these symptoms, reduce your exposure
to particles and follow your doctor's advice. Contact your doctor
if symptoms persist or worsen. If you have asthma,
carefully follow your asthma management plan when particle levels
are high. Your doctor can help you develop a plan if you don't have
one.
If you have heart disease, particle exposure can
cause serious problems in a short period of time—even heart
attacks—with no warning signs. So don't assume that you are
safe just because you don't have symptoms. Symptoms such as chest
pain or tightness, palpitations, shortness of breath, or unusual
fatigue may indicate a serious problem. If you have any of these
symptoms, follow your doctor's advice.
How can you avoid unhealthy exposure?
Your chances of being affected by particles increase the more strenuous
your activity and the longer you are active outdoors. If your activity
involves prolonged or heavy exertion, reduce your activity time—or
substitute another that involves less exertion. Go for a walk instead
of a jog, for example. Plan outdoor activities for days when particle
levels are lower. And don't exercise near busy roads; particle levels
generally are higher in these areas.
Particle levels can be elevated indoors, especially when outdoor
particle levels are high. Certain filters and room air cleaners
can help reduce indoor particle levels. You also can reduce particle
levels indoors by not smoking inside, and by reducing your use of
other particle sources such as candles, wood-burning stoves, and
fireplaces.
How can the Air Quality Index help?
In
many areas, local media provide air quality forecasts
telling you when particle levels are expected to be unhealthy. Forecasts
use the same format as EPA's Air Quality Index, or AQI, a tool that
state and local agencies use to issue public reports of actual levels
of particles, ground-level ozone, and other common air pollutants.
Using the AQI's color-coded scale, these forecasts help you quickly
learn when air pollution is expected to reach unhealthy levels in
your area. In the newspaper forecast shown at right, for example,
the black arrow points to the "orange" range, indicating
that particle levels are expected to be unhealthy for sensitive
groups. On television, you might hear a meteorologist say something
like this: "Tomorrow will be a code orange air quality
day, with particle pollution at levels that are unhealthy for sensitive
groups. If you have heart or lung disease, or if you're an older
adult or a child, you should plan strenuous activities for a time
when air quality is better."
AIR QUALITY
INDEX FOR PARTICLE POLLUTION
|
Air Quality Index |
Air Quality |
Health Advisory |
0-50
|
Good
|
None. |
51-100
|
Moderate
|
Unusually sensitive people should consider reducing prolonged
or heavy exertion. |
101-150
|
Unhealthy for
Sensitive Groups
|
People
with heart or lung disease, older adults, and children should
reduce prolonged or heavy exertion. |
151-200
|
Unhealthy
|
People with
heart or lung disease, older adults, and children should avoid
prolonged or heavy exertion. Everyone else should reduce prolonged
or heavy exertion. |
201-300
|
Very
Unhealthy
|
People with heart or lung disease, older adults, and children
should avoid all physical activity outdoors. Everyone else should
avoid prolonged or heavy exertion. |
AIRNow
AIRNow (www.epa.gov/AIRNow)
is a Web site that gives daily information about air quality,
including ground-level ozone and particles, and how they may
affect you. AIRNow contains:
- Real-time particle levels for many locations.
- Air quality forecasts for many cities across the country.
- Kids' Web page and associated teacher curriculum.
- Smoke Web page.
- Links to state and local air quality programs.
- Ideas about what you can do to reduce particles. For example,
you can keep your car, boat, and other engines well-tuned,
and avoid using engines that smoke. You can also participate
in local energy conservation programs.
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*Photo courtesy of the Weather Channel.
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