Airborne particulate matter, called PM, is a result of smoke, soot, and fly ash
from factories or power plants. It includes minute pieces of solids or liquids
dispersed into the atmosphere, primarily by combustion. The major particles from
these industries are carbon, ash, oil, and grease. Particulate can also be produced
by rock, sand, and gravel processing and by cement, steel, and iron industries. These
industries discharge microscopic amounts of metals and metal oxides into the atmosphere.
Total suspended particulate (TSP) results in visible air pollution: dust, smoke, haze, and mist.
What the Numbers Mean
Particulate matter (PM) comprises very small dust and
soot particles. There are two categories of PM: PM10 consists of particles
that are 10 micrometers in diameter, and PM2.5 particles measure 2.5 micrometers or less.
Total suspended particulate (TSP) is measured
by a PM10 sampler, which collects particles that are 10 micrometers (approximately
0.0004 inches) and smaller. We measure TSP in micrograms per cubic meter of a 24-hour
period. Levels above 150 micrograms/cubic meter exceed NAAQS.
Both fine and coarse particles can accumulate in the
respiratory system and are associated with numerous health effects. Coarse particles
can aggravate respiratory conditions such as asthma. Exposure to fine particles is
associated with several serious health effects, including premature death. Adverse
health effects have been associated with exposures to PM over both short periods
(such as a day) and longer periods (a year or more).
When exposed to PM, people with existing heart or
lung diseases—such as asthma, chronic obstructive pulmonary disease, congestive
heart disease, or ischemic heart disease—are at increased risk of premature death
or admission to hospitals or emergency rooms.
The elderly also are sensitive to PM exposure. They
are at increased risk of admission to hospitals or emergency rooms and premature
death from heart or lung diseases. When exposed to PM, children and people with
existing lung disease may not be able to breathe as deeply or vigorously as they
normally would, and they may experience symptoms such as coughing and shortness
of breath. PM can increase susceptibility to respiratory infections and can aggravate
existing respiratory diseases, such as asthma and chronic bronchitis, causing more
use of medication and more doctor visits.
Exposure to elevated particulate levels can:
- Aggravate respiratory disorders such as coughing, chest colds, asthma, and pneumonia
- Increase incidences of emphysema, lung cancer, and chronic bronchitis
- Obscure vision, leading to high accident potential
- Corrode metals
- Cause grime on buildings and belongings
- Soil, disfigure, and damage stone, brick, paint, glass, and other composite materials
- Damage plants and trees with dust deposits that solidify on plant surfaces and inhibit growth, injure plant tissue, and interfere with pollination
- Alter weather and climate by increasing rainfall and reducing sunlight penetration