Fine Particles Reduce Air Quality Across Iowa

March 9, 2007

DES MOINES - Air quality levels approaching health standards were present over most of Iowa on Thursday and remain elevated Friday, according to the DNR.

A DNR monitoring station at Emmetsburg in northwest Iowa recorded a value of 36.6 micrograms per cubic meter (ug/m3) on Thursday. The U.S. Environmental Protection Agency (EPA) health standard for fine particles is 35.5 ug/m3. Monitoring sites across most of Iowa remain in the 20-30 ug/m3 range as a band of poor air quality continues eastward across the upper Great Plains and Midwest.

The EPA predicts a low pressure system will move toward the eastern Great Lakes from the southern Plains on Saturday, enhancing mixing, dispersing particles and lowering values in the western portion of the Midwest.

Fine particles are emitted by vehicle traffic and other combustion sources and are also formed by chemical reactions in the atmosphere. Stagnant air masses do not allow the fine particles to disperse and cause pollutant levels to rise.

The DNR recommends that individuals throughout Iowa with respiratory or heart disease, as well as the elderly and children, limit prolonged exertion until air quality conditions improve on Saturday.

EPA’s national air quality map is available online at www.airnow.gov.

For more information contact Sean Fitzsimmons at Sean.Fitzsimmons@dnr.iowa.gov or at (515) 281-8923.