New IEC Report Shows Unhealthy Air Quality in Sioux City and Highlights Health Effects

For immediate release 

SIOUX CITY—Today, the Iowa Environmental Council released a new report, “Air Quality in Siouxland: How Grassroots Action Exposed the Truth about Pollution.” The report shows that the Sioux City area frequently experiences acute air pollution events, during which levels of PM2.5 (fine particulate matter) surpass the EPA’s thresholds for “unhealthy for sensitive groups” and “unhealthy” for the general public. 

Data in the report comes from six PurpleAir monitors that Woodbury County residents installed with the assistance of IEC in 2025. 

“This grassroots air monitoring initiative grew out of reports in 2024 and 2025 that Woodbury County had the highest rates of asthma in the state,” said Lexi McKee-Hemenway, IEC’s Sioux City Campaign Organizer. “Residents wanted access to real-time air quality data, and they wanted to understand the sources of air pollution in our community.” 

Woodbury County is home to two of MidAmerican Energy’s coal-fired power plants: George Neal North and George Neal South. IEC analyzed emissions data from the two plants and trends in data from the air monitors for the report. 

“Spikes in PM2.5 levels coincide with coal plant operations,” said Steve Guyer, IEC’s Senior Energy Policy Counsel and one of the report’s authors. “Woodbury County’s air quality is shaped by industrial polluters, high traffic volume, and MidAmerican’s coal plants. What differentiates these sources of pollution is that PM2.5 from coal plants is more dangerous than that from other sources.” 

The report highlights scientific and medical research that shows that PM2.5 originating from coal plants is associated with higher risk of cancer and mortality than other types of PM2.5. It is often enriched with highly toxic trace elements, including neurotoxins like mercury and carcinogens such as arsenic, cadmium, chromium, and lead. 

PM2.5 is a type of air pollution, made up of microscopic liquid droplets and solid particles suspended in the atmosphere. At 2.5 microns or less in diameter — roughly 30 times smaller than a single strand of human hair — these particles are invisible to the naked eye and can only be detected via microscopy. PM2.5 is one of the most widespread and hazardous forms of air pollution. 

“Air pollution is an issue across Iowa, but the effects are not felt uniformly,” said Jordan Oster, Energy Program Director at IEC. “The Sioux City community is bearing the health impacts of MidAmerican Energy’s dirty coal plants. We need our utilities to transition away from coal, and until they do so, our utilities should be held responsible for the cost of their pollution.” 

The report includes policy recommendations to protect communities from dangerous coal plant pollution. These recommendations include that local policymakers develop a text or email alert system to inform the public when air pollution reaches unsafe levels, and that utilities and local policymakers support communities affected coal plant pollution with acquiring indoor air purifiers. The report also recommends that the Iowa Department of Natural Resources expand its ambient air monitoring system to include continuous air monitors in communities disproportionately affected by air pollution. 

IEC is hosting an expert panel presentation about the report and the health effects of air pollution on August 13 from 5:30 to 6:30 at the Sioux City Public Museum, 607 4th St., Sioux City, IA 51101. The event is free and open to the public and members of the press.

Click here to read the executive summary, and click here to access the full report. For additional information or to arrange an interview with report authors, please contact Bethany Kohoutek at kohoutek@iaenvironment.org.