Particulate Matter

Particulate matter also known as Particle Pollution, or PM, is the term used for a complex mixture of extremely small particles found in the air. Some of the components found in PM include: dust, dirt, the principal constituents of soot and smoke, droplets of acids such as nitrates or sulfates, organic chemicals and metals.
These particles can stay suspended in the air for long periods of time and the size of the particles is directly linked to their potential to cause health problems. The APCD is especially concerned with particles that are 10 microns or less, in diameter, for these are the ones which pass through the nose and throat and enter the lungs. Once inhaled, these particles can affect the heart and lungs and have some serious adverse health effects.
Larger or darker particles can be seen by the naked eye and normally are identified as soot or smoke, other inhalable coarse particles, such as those found near roadways and dusty industries, are so small that individually they can only be detected with the aid of a microscope.
Some particles are directly emitted into the air. They come from a variety of sources such as cars, trucks, buses, factories, construction sites, tilled fields, unpaved roads, stone crushing, and burning of wood.

Some other particles may be formed, when gases emitted from power plants, interact with each other or with other elements or compounds present in the air. Sunlight and water vapor may be vital components in the formation of these particles.

 

Chief Causes for Concern

Particle pollution, especially fine particles contains microscopic solids or liquid droplets, so small that, they can get deep into the lungs and cause some serious health problems. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including:

Increased respiratory ailments,
difficulty breathing,
decreased lung function,
aggravated asthma,
development of chronic bronchitis,
irregular heartbeat,
non-fatal Heart attacks and possible premature death in people with heart and lung disease.

Excessive PM is one of the major contributors to the formation of urban haze, often enveloping entire cities and sorrounding areas, it reduces visibility in many parts of California, including our National Parks; it is also one of the principal causes of aggravated health issues, among people with hyper sensitivities and those with an already existing heart or lung condition, responsible for many work and school absences.
PM is also to blame for: changing the nutrient and chemical balance in the soil and surface water, erosion and staining of many structures, including culturally important objects such as monuments and sculptures.

Existing health problems can get worse, and, sensitive people may incur respiratory distress, if they are exposed to high levels of PM for several days in a row.