Linn County Air Quality Division
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Wildfire Haze Over Iowa Dissipates

July 08, 2015

Iowa Department of Natural Resources released the following statement:

"Fine particulate (PM2.5) levels fell across eastern Iowa today. As of 10 a.m. today, hourly PM2.5 levels across the state have fallen, with air quality expected to be in the Good (Green) or Moderate (Yellow) for the remainder of the day.  

Better conditions today follow unusually high fine particulate levels in eastern Iowa after a plume of smoke originating from Canadian wildfires passed southeastward through the state yesterday.


The U.S. Environmental Protection Agency’s (EPA) 24-hour health threshold for PM2.5 is 35 micrograms per cubic meter. Most monitoring sites in eastern Iowa recorded levels exceeding this threshold yesterday. Daily average PM2.5 concentrations on Tuesday in Cedar Rapids, Iowa City, Clinton, Muscatine, Davenport and Lake Sugema were 40.0, 48.2, 53.4, 57.0, 58.7 and 60.3 micrograms per cubic meter respectively. 

EPA uses a simple color scale to further categorize air quality. Daily average concentrations between 35.5 and 55.4 micrograms per cubic meter fall into EPA’s Unhealthy for Sensitive Groups (Orange) category.  When air quality is in the Orange range, asthmatics, individuals with heart or lung disease, as well as the elderly and children may experience adverse health effects. Concentrations between 55.5 and 150.4 micrograms per cubic meter fall into EPA’s Unhealthy or Red category. When air quality is in the Red range, everyone may experience adverse health effects. 

Find more information about EPA’s air quality index (AQI) a

To generate PM2.5 maps in real time, when data for the entire day is not yet available, EPA uses a surrogate for the 24-hour average concentration, called the NowCast. To learn more about the NowCast see"

Contact Todd Russell, Iowa DNR Air Quality Ambient Monitoring at (515) 725-9561 or Linn County Public Health's Air Quality Branch at (319) 892-6000.