Hundreds of thousands of Americans have been advised to remain indoors and keep windows shut as a major air quality warning sweeps across the Upper Midwest. Approximately 300,000 residents in Minnesota, North Dakota, and South Dakota are currently enveloped in a plume of hazardous and unhealthy air, driven by dust storms moving across the northern United States.
EPA Declares Hazardous Conditions
The US Environmental Protection Agency (EPA) classified the air over Watertown, South Dakota—home to nearly 24,000 people—as 'hazardous' to human health on Thursday afternoon. According to the World Air Quality Index project, a nonprofit providing real-time air pollution data globally, the air quality index (AQI) in Watertown reached 439 at 1pm ET. When outdoor AQI enters the 300 to 500 hazardous zone, the EPA warns that everyone should avoid all physical activity outdoors.
Unhealthy Air in Fargo
Another plume of 'unhealthy' air was detected over Fargo, North Dakota, a city of over 130,000 people located on the border with Minnesota. The primary pollutant in these dust storms has been identified as PM10, a type of fine particulate matter consisting of tiny solid particles or liquid droplets in the air, less than 10 micrometers in diameter—thinner than a human hair.
While PM10 is noticeably larger than PM2.5, which typically contains toxins or heavy metals from factories and vehicle exhaust, it can still damage the lungs, worsen respiratory conditions such as asthma, and contribute to heart attacks and strokes that can lead to premature death.
This is a developing story. Further updates will follow. Dust storms across the Upper Midwest are causing widespread air quality alerts on Thursday, May 14. Hazardous and unhealthy air conditions in Minnesota and the Dakotas were detected on May 14, and predictions indicate these conditions may persist into the weekend.
