Air Quality in Northeast Iowa Improves

Pollutant levels exceeding U.S. Environmental Protection Agency (EPA) health standards for fine particles were present over northeast Iowa Sunday, but fell this morning as a winter storm advanced through the state. At 11 a.m. today, February 25, fine particle levels across the state have fallen, with 12-hour averages ranging from 14.4 m at Viking Lake in southwest Iowa to 25.9 at Cedar Rapids.

The EPA’s 24-hour health standard for fine particles is 35 micrograms per cubic meter.

On Sunday, fine particle concentrations averaged 35 micrograms per cubic meter in Davenport, 45 micrograms per cubic meter in Clinton, and 41 micrograms per cubic meter in Cedar Rapids. Monitors in the rest of the state recorded lower values; 25 micrograms per cubic meter in Des Moines, 25 micrograms per cubic meter at Lake Sugema in southeast Iowa and 21 micrograms per cubic meter at Viking Lake.

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 more information contact Todd Russell at Todd.Russell@dnr.iowa.gov or at (515) 281-8437.