Particle Pollution 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. Particle pollution comes from a variety of natural and man-made sources such as cars, power plants and forest fires.

Particulate Matter (PM2.5) Fine particles (less than 2.5 micrometers in diameter (PM2.5)) can accumulate in the respiratory system. Fine particles often come from fuel combustion, power plants, and diesel buses and trucks.

Adverse health effects resulting from PM 2.5 include decreased lung function and increased respiratory symptoms and disease, aggravated asthma, chronic bronchitis, painful or difficult breathing and shortness of breath. Sensitive groups that appear to be at greatest risk include the elderly, individuals with cardiopulmonary disease such as asthma, and children. (click here for more detailed information)*

Environmental effects of PM2.5 include reduced visibility in parts of the United States. In many parts of the U.S. the visual range has been reduced 70 percent from natural conditions. In the East, the current range is only 14-24 miles vs. a natural visibility of 90 miles. In the West, the current range is 33-90 miles vs. a natural visibility of 140 miles. Fine particles can also remain suspended in the air and travel long distances. So for example exhaust from a diesel truck in Los Angeles can end up over the Grand Canyon!

Ozone Pollution is formed ground-level, where we breathe it whereas the stratospheric ozone layer protects us from the sun's harmful rays. In the summer, sunlight and high temperatures 'bake' pollutants emitted by motor vehicles, power plants, industrial manufacturing and other sources to form high levels of ground-level ozone, commonly known as smog.

*The Elderly

Studies indicate that exposure to fine particles is associated with thousands of hospital admissions each year. Many of these hospital admissions are elderly people suffering from lung or heart disease.

Individuals with Preexisting Heart or Lung Disease

Breathing fine particles can also adversely affect individuals with heart disease, emphysema, and chronic bronchitis by causing additional medical treatment. Inhaling fine particulate matter has been attributed to increased hospital admissions, emergency room visits and premature death among sensitive populations.

Children

The average adult breathes 13,000 liters of air per day; children breathe 50 percent more air per pound of body weight than adults. Because children's respiratory systems are still developing, they are more susceptible to environmental threats than healthy adults.

Exposure to fine particles is associated with increased frequency of childhood illnesses, which are of concern both in the short run, and for the future development of healthy lungs in the affected children.

Fine particles are also associated with increased respiratory symptoms and reduced lung function in children, including symptoms such as aggravated coughing and difficulty or pain in breathing. These can result in school absences and limitations in normal childhood activities.

Asthmatics and Asthmatic Children

More and more people are being diagnosed with asthma every year. Fourteen Americans die every day from asthma, a rate three times greater than just 20 years ago. Children make up 25 percent of the population, but comprise 40 percent of all asthma cases.

Breathing fine particles, alone or in combination with other pollutants, can aggravate asthma, causing greater use of medication and resulting in more medical treatment and hospital visits.