Stagnant Air and Fog Cause Fine Particle Levels to Rise in Eastern Iowa

Pollutant levels approaching U.S. Environmental Protection Agency (EPA) health standards for fine particles were present over most of Eastern Iowa Wednesday morning. At this level the air can be unhealthy for sensitive groups.

The DNR recommends that Iowans with respiratory or heart disease, the elderly, and children limit prolonged exertion until air quality conditions improve.

The EPA’s 24-hour health standard for fine particles is 35 micrograms per cubic meter. At mid day fine particle levels in Clinton averaged 56 micrograms per cubic meter and in Davenport 49 micrograms per cubic meter. Fine particle levels are expected to remain elevated through Friday.

Fine particles are emitted by vehicle traffic and other combustion sources and also formed by chemical reactions in the atmosphere. Stagnant air masses do not allow the fine particles to disperse, and pollutant levels rise. In the winter, fog droplets at near freezing temperatures capture ammonia and nitric acid and give rise to fine particles made of ammonium nitrate.

EPA’s national air quality map is available online at www.airnow.gov. For current particulate matter information, click on “Particles Now” underneath the map.

For more information contact Sean Fitzsimmons, Ambient Air Monitoring, (515) 281-8923 or Mindy Kralicek, Air Quality Information Specialist, (515) 281-7832.