Fine Particles (PM2.5)

Fine Particulate Matter - What is PM2.5?

Particulate matter 2.5 is microscopic solids or liquid droplets of pollution that are so small (smaller than a red blood cell) they bypass the body’s normal protections and may lodge in the lungs causing scarring and decreased lung function. Fine particles may also pass into the blood stream and contribute to plaque buildup in arteries, increase the risk for and effects of heart disease, and enter the organs and the nervous system, including the brain.

Numerous scientific studies have linked particle pollution exposure to a variety of health problems:

  • increases in respiratory symptoms such as irritation of the airways, coughing, or difficulty breathing
  • decreased lung function;
  • aggravated asthma;development of chronic bronchitis;
  • irregular heartbeat;
  • heart attacks; and
  • premature death.

PM2.5 is generated by all types of combustion: motor vehicles, power plants, wood burning and some industrial processes. Most fine particle pollution is formed when organic compounds, nitrogen oxides, ammonia and sulfur dioxide react in the atmosphere to form secondary PM2.5.

Areas of Iowa have teetered on the edge of exceeding the Environmental Protection Agency’s attainment standard for PM2.5 since it was strengthen in December 2006.

There are economic implications for areas classified as nonattainment. Expensive pollution control equipment or limits on production or expansion can cost Iowa economic vitality and loss of job growth. Although industries can apply stricter emission strategies to reduce fine particle pollution in immediate areas, pollution reduction strategies are needed across the state and the U.S. to lower the background pollution levels that will keep Iowa from exceeding attainment status.

The DNR helps industries and other permitted pollution emitters with strategies to reduce their emissions. However, there are many other sources of PM2.5 that contribute to the background ambient air levels of PM2.5: automobile emissions, open burning, wild fires, and dust.

Depiction of the size of PM10 and PM2.5 with respect to a human hair (hair averages 70 microns in diameter, PM10 is 10 microns and PM2.5 is 2.5 microns)

Additional Resources