What is particle
Particle pollution, called particulate
matter or PM, is a combination of fine solids and aerosols that are
suspended in the air we breathe.
Particles are made up of different
things. “A mixture of mixtures” is how the U.S.
Environmental Protection Agency (EPA) describes
them.1 PM can be solids, like dust, ash, or soot.
PM can also be completely liquid aerosols or solids suspended in
Particles are different
sizes. The ones of most concern are small
enough to lodge deep in the lungs where they can do serious
damage. They are measured in microns. The largest of concern
are 10 microns in diameter (PM10). The group of most
concern is 2.5 microns in diameter or smaller
(PM2.5). Some of these are small enough to pass
from the lung into the bloodstream just like oxygen
molecules. By comparison, the diameter of a human hair is
huge—it’s 70 microns.
Particles come from different
sources. Burning fuel is a major source of the
smallest types of particle pollution —whether from woodstoves to
diesel trucks and buses to coal-fired power plants. Larger
particles also come from other sources, including agricultural
practices or wind-blown soil and dust.
What are the health effects of particulate
Short-term increases (over hours to days)
in particle pollution have been linked to:
death from respiratory and cardiovascular causes,
increased numbers of heart attacks, especially
among the elderly and in people with heart
inflammation of lung tissue in young, healthy
increased hospitalization for cardiovascular
disease, including strokes;7,8
increased emergency room visits for patients
suffering from acute respiratory ailments;9
increased hospitalization for asthma among
increased severity of asthma attacks in
Year-round exposure to particle pollution has also been linked
- increased hospitalization for asthma attacks for children
living within 200 meters (218 yards) of roads with heavy truck or
- slowed lung function growth in children and
- significant damage to the small airways of the
- increased risk of dying from lung cancer; and18
- increased risk of death from cardiovascular
How serious is the impact?
one example: EPA scientists estimated that over 4,700
premature deaths occur each year in just nine cities
analyzed (Detroit, Los Angeles, Philadelphia, Pittsburgh, St. Louis,
Boston, Phoenix, Seattle, and San Jose) even if those cities all met
the current PM2.5 standard.20 Extrapolating
these data would mean many thousands of more deaths nation-wide, but
EPA has not calculated that total. Other studies have estimated the
nationwide death toll to be tens of thousands
Who is at risk?
Anyone may be
affected by particle pollution, but several groups are most at
- Children under 18
- Adults 65 and older
- Anyone with chronic lung diseases, such as asthma, chronic
bronchitis, or emphysema
- Anyone with a cardiovascular disease, such as a coronary
artery disease or who has suffered a stroke or heart attack
- Anyone with diabetes
How can you protect yourself and your
- Check daily air quality levels and air pollution
forecasts in your area. Sources include local radio and
TV weather reports, newspapers and online at www.epa.gov/airnow/. You can even have the
information email or sent to your cellphone.
- Don’t burn wood or trash. Burning firewood
and trash are among the major sources of particle pollution in
many parts of the country. If you must use a fireplace or stove
for heat, convert your woodstoves to natural gas, which produces
far fewer emissions.
- Avoid exercising outdoors when pollution levels are
high. Walk indoors in a shopping mall or gym or use an
exercise machine. Always avoid exercising near high traffic areas.
Limit the amount of time your child spends playing outdoors if the
air quality is unhealthy.
- Encourage your child’s school to reduce school bus
emissions. Most buses use heavily polluting diesel
engines; newer fuels and engines are cleaner. Many school systems
are using the EPA’s Clean School Bus Campaign to clean up these
dirty emissions. Schools are also not allowing school buses to
idle at the building, to keep exhaust levels down.
- Don’t smoke or allow anyone to smoke
indoors. Cigarette smoke produces large amounts of
particle pollution among its many toxic components.
What should be done to protect the public from
- EPA needs to require old, dirty coal-fired power
plants to become cleaner, sooner. EPA needs to tell
these large plants that they must reduce their emissions that help
form the smallest particles. Some states are considering stronger
requirements that could reduce emissions even more.
- EPA needs to make final proposed rules that would
clean up locomotive and marine diesel engines. EPA
proposed tighter standards for trains and ships in March 2007, but
these need to be made final to take effect.22
- EPA needs to set more protective national air quality
standards for particle pollution. The national air
quality standards are the clean air goals that the states and
counties must reach. They drive all the federal, state, and local
measures to clean up air pollution. Although EPA issued new
standards in September 2006, these new standards fail to protect
public health as much as the science showed was needed. The
American Lung Association and other public health and medical
societies supported lower levels.23
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22. U.S. EPA. Regulatory Announcement: EPA
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Compression-Ignition Engines. March 2,2007. At http://www.epa.gov/otaq/regs/nonroad/420f07015.htm.
23. See more information on the American Lung
Association recommendations at http://www.cleanairstandards.org/.