Particle Pollution

A big problem in a very small package!

Particle Pollution or Particulate Matter (PM) is tiny drops of liquid or small particles of dust, metals and other materials that float in the air. Some particles are large or dark enough to be seen, others are so small that they can only be detected with an electron microscope. PM is measured in micrometers, with matter less than 10 micrometers in diameter posing the greatest health risk. Particles less then 2.5 micrometers in diameter are described as being 'fine' particles. These particles are easily inhaled and can become lodged in the lungs and produce respiratory illness.

PM comes from a variety of natural sources including volcanic ash, salt from ocean spray, forest fires, and dust from fields. Man-made PM comes from the burning of wood, diesel, and other fuels. Various processes that take place in industrial plants, such as incineration, are also large sources of PM distribution. PM greater then 2.5 micrometers in diameter is usually the result of smoke and dust from industry and agricultural production, while particles less then 2.5 generally come from combustion of fossil fuels.

How to Burn Wood Wisely and Reduce Particle Pollution!

Adverse Health Effects

Particle pollution - especially fine particles - can get deep into the lungs and cause serious health problems. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including:

  • Increased respiratory symptoms, such as irritation of the airways, coughing, or difficulty breathing

  • Decreased lung function

  • Aggravated asthma

  • Development of chronic bronchitis

  • Irregular heartbeat

  • Nonfatal heart attacks

  • Premature death in people with heart or lung disease.

People with heart or lung diseases, children and older adults are the most likely to be affected by particle pollution exposure. However, even if you are healthy, you may experience temporary symptoms from exposure to elevated levels of particle pollution. For more information about asthma, visit

Environmental Effects

Reduced Visibility

Fine particles (PM2.5) are the major cause of reduced visibility (haze) in parts of the United States, including many of our treasured national parks and wilderness areas. For more information about visibility, visit

Environmental Damage

Particles can be carried over long distances by wind and then settle on ground or water. The effects of this settling include: making lakes and streams acidic; changing the nutrient balance in coastal waters and large river basins; depleting the nutrients in soil; damaging sensitive forests and farm crops; and affecting the diversity of ecosystems.
More information about the effects of particle pollution and acid rain.

Aesthetic Damage

Particle pollution can stain and damage stone and other materials, including culturally important objects such as statues and monuments. More information about the effects of particle pollution and acid rain.