Another air pollution alert issued for Eastern Iowa

The Iowa Department of Natural Resources issued another pollution warning today.

Elevated fine particle levels were recorded in northeast Iowa and Johnson County this morning.

Fine particulate levels near EPA health standards are expected to continue until late Saturday morning.

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

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

As of noon today, fine particle levels averaged in the high 30s to low 40s across parts of northeast Iowa.

Monitors recorded fine particulate levels at 39 in Cedar Rapids, 36 in Iowa City, and 54 in Waterloo.

Yesterday, an air monitor in Waterloo recorded a 24-hour fine particle level of 41, Cedar Rapids recorded a level of 36, Davenport recorded 36, and Muscatine recorded 43.

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

The fine particle levels in the state have been following a pattern of rising rapidly during the evening and nighttime hours, and falling back to levels below the standard in late morning or early afternoon.

This cycle is expected to continue until winds pick up Saturday afternoon.

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

See real-time data for Linn County at: www.linncleanair.org