About Air

Particle Pollution

Particle Pollution is the general term used for a mixture of solid particles and liquid droplets found in the air. This pollution, also known as particulate matter, is made up of a number of components, including acids (such as sulfates and nitrates), organic chemicals, metals, soil or dust particles and allergens (such as fragments of pollen or mold spores).

The size of the particles is directly linked to their potential for causing health problems. Small particles pose the greatest threat. PM2.5 describes the small particles of concern, they are "fine particles" (such as those found in smoke and haze) which are 2.5 micrometers in diameter or less. "Coarse" particles describe particles greater than 2.5, but less than or equal to 10 micrometers in diameter. PM10 refers to all particles less than or equal to 10 micrometers in diameter. Ten micrometers are about one-seventh the diameter of human hair.

Particle Pollution originates from many different stationary and mobile sources as well as from natural sources. Fine particles can result directly from emissions of fuel combustion from motor vehicles, power generation, and industrial facilities, as well as from residential fireplaces and wood stoves. In other cases, gases such as sulfur dioxide, nitrogen oxides, and volatile organic compounds interact with other compounds in the air to form fine particles. Coarse particles are generally emitted from sources such as vehicles traveling on unpaved roads, materials handling, crushing and grinding operations, and windblown dust. Their chemical and physical compositions vary depending on location, time of year, and weather.

When breathed, both fine and coarse particles can accumulate in the respiratory system and are associated with numerous health effects. Exposure to coarse particles is primarily associated with the aggravation of respiratory conditions, such as asthma. Fine particles are most closely associated with such health effects as increased hospital admissions and emergency room visits for heart and lung disease, increased respiratory symptoms and disease, decreased lung function, and even premature death. Sensitive groups that appear to be at greatest risk to such effects include those with heart or lung disease, older adults, and children. In addition to health problems, particle pollution is the major cause of reduced visibility in many parts of the U.S. Airborne particles also can impact vegetation and ecosystems and can cause damage to paints and building materials.

The U.S. Environmental Protection Agency has established two health-based air quality standards for particle pollution, one for PM2.5 and the other for PM10. The Florida Department of Environmental Protection, in cooperation with several county air pollution control agencies, monitors particle pollution air quality throughout the state.