Particulate Matter (PM) Effects
at general risk for suffering adverse health effects from exposures to
particulate matter include children, people of all ages with asthma, and
the elderly with illnesses like bronchitis, emphysema and pneumonia. Patients with chronic obstructive pulmonary disease, such as
emphysema and bronchitis, are also potentially susceptible to mortality
because of their vulnerability to physical and chemical stimuli and the
absence of an adequate ventilatory reserve.
can be inhaled through the upper respiratory airways, and deposited in
the lungs causing serious health problems and the increased likelihood
of death from other causes. Some
of the particles that measure less than 10 microns can penetrate and
deposit deeply in the lungs without an ability to be exhaled.
This smaller fraction, commonly referred to as PM2.5, is of
special concern to health. These
particles are based on the fraction of PM10 that measures at less than
2.5 microns in diameter. These
finer particles are easily inhaled deeply into the lungs where they can
be absorbed into the bloodstream or remain embedded for long periods of
time. Finer particles may be
aerosol carriers of toxic and biological materials, which can be
absorbed by the blood in the gas exchange tissues of the lungs and
carried to other parts of the body.
Effects on the Environment
fine particles that are linked to serious health effects are also a
major cause of visibility impairment (regional haze) in many national
parks. The term regional
haze means haze that impairs visibility in all directions over a large
area. Regional haze
consists of sufficient smoke, dust, moisture, and vapor suspended in air
to impair visibility. Particulate
matter that is formed when gaseous pollutants react in the atmosphere
also causes regional haze. These
particles often grow in size as humidity increases, further impairing
hundreds or even thousands of miles away can contribute to visibility
problems at remote locations. In
the west, the visual range has been reduced to over 60 percent.
Haze currently reduces visibility from approximately 140 miles to
between 33 and 90 miles.
For questions associated with this