What
are particles? Where do they come from?
Particles in the air are a mixture of solids and liquid droplets
that vary in size and are often referred to as "particulate
matter." Some particles - those less than 10 micrometers in
diameter - pose the greatest health concern because they can
pass through the nose and throat and get deep into the lungs.
Ten micrometers in diameter is just a fraction of the diameter
of a single human hair. Particles larger than 10 micrometers
do not usually reach your lungs, but they can irritate your
eyes, nose and throat.
Very small particles with diameters less than 2.5 micrometers
are called "fine particles." They are produced any time fuels
such as coal, oil, diesel or wood are burned. Fine particles
come from fuel used in everything from power plants to wood
stoves and motor vehicles (e.g., cars, trucks, buses and marine
engines). These particles are even produced by construction
equipment, agricultural burning and forest fires.
"Coarse" dust particles range in size from 2.5 to 10 micrometers
in diameter. Particles of this size are produced during crushing
or grinding and from vehicles traveling on paved or unpaved
roads.
How
can particle pollution affect you?
Fine and coarse particles can cause a variety of serious health
problems. When exposed to these particles, people with heart
or lung diseases and older adults are more at risk of hospital
and emergency room visits or, in some cases, even death. These
effects have been associated with short-term exposures lasting
24 hours or less. Long-term exposures of a year or more have
been linked to the development of lung diseases, such as chronic
bronchitis.
Particles can aggravate heart diseases such as congestive
heart failure and coronary artery disease. If you have heart
disease, particles may cause you to experience chest pain,
palpitations, shortness of breath and fatigue. Particles have
also been associated with cardiac arrhythmias and heart attacks.
Particles can aggravate lung diseases such as asthma
and bronchitis, causing increased medication use and doctor
visits. If you have lung disease, and you are exposed to particles,
you may not be able to breathe as deeply or vigorously as
normal. You may have respiratory symptoms including coughing,
phlegm, chest discomfort, wheezing and shortness of breath.
You also may experience these symptoms even if you're healthy,
although you are unlikely to experience more serious effects.
Particles can also increase your susceptibility to respiratory
infections.
How
can you reduce your exposure to particles?
Air pollution levels can vary throughout the day. Your local
air quality forecast can tell you when particle levels are
high in your area. You can reduce your exposure to particles
by 1) planning strenuous activity when particle levels are
forecast to be lower, 2) reducing the amount of time spent
at vigorous activity, or 3) choosing a less strenuous activity
(e.g., going for a walk instead of a jog).
When particle levels are high outdoors, they also can be high
indoors. Certain filters and room air cleaners are available
that can help reduce particles indoors. You also can reduce
particles indoors by eliminating tobacco smoke and reducing
your use of candles, wood-burning stoves and fireplaces. For
more information on indoor air pollution and filter devices,
visit www.epa.gov/iaq.
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