NEXSTAR – On Thursday, parts of the U.S. reported the worst air quality globally due to wildfire smoke originating from Canada and Minnesota. The smoke began to spread through the upper Midwest and the Northeast on Wednesday, creating hazy skies and an unpleasant odor affecting millions. The situation is expected to worsen by Friday, moving further south through the Midwest and reaching Appalachia and the East Coast.
The Environmental Protection Agency’s U.S. Air Quality Index reported that northern Minnesota showed exceptionally poor air quality on Thursday morning. The interactive map indicated areas across Minnesota, Wisconsin, and Michigan, along with neighboring regions, reflecting shades of purple and maroon. These colors signify dangerously high AQI levels. Purple indicates an AQI ranging from 201 to 300, which poses a health risk to everyone. Maroon, indicating AQI levels of 301 or higher, presents a hazardous level of concern.
As of 10 a.m. ET, north-central Minnesota recorded the worst air quality nationwide, with an AQI of 1,421. This figure is nearly five times above the minimum level considered hazardous. As a result, camps in Northern Minnesota are closing, and wilderness trips are being shortened due to wildfires reported by Minnesota Public Radio. Earlier this week, wildlife officials evacuated the Boundary Waters Canoe Area Wilderness.
Reports from Ely, Minnesota, indicated multiple wildfires prompting closures and evacuations. Willy Vosburgh, owner of Vosburgh’s Custom Cabin Rentals, used a tow boat to evacuate canoeists from the wilderness area. Plumes of smoke were visible over Moose Lake as wildfires raged on.
The Minnesota Arrowhead area and Duluth are ranked as No. 2 and No. 3 areas with the worst air quality, registering AQI levels of 1,086 and 923, respectively.
Other areas with poor air quality include:
- Toledo, Ohio: 649 AQI
- Eastern Northwoods, Wisconsin: 627 AQI
- Eastern Upper Peninsula, Michigan: 622 AQI
- Southeast Michigan: 622 AQI
- Grand Rapids, Michigan: 616 AQI
- Central Minnesota: 607 AQI
- Western Upper Peninsula, Michigan: 596 AQI
These regions are experiencing some of the worst air quality globally. IQ Air ranked Detroit as the most polluted, with an AQI of 600. Toronto and Minneapolis follow, while Chicago exhibited a lower AQI.
Sections of New York and Pennsylvania displayed unhealthy air quality levels on the EPA’s map. Philadelphia recorded an AQI of 182. Forecasts predict Minnesota and Wisconsin may face the worst conditions, with uncomfortable air in other states like Michigan, New Jersey, and parts of Pennsylvania.
By Friday, forecasts suggest improvements, although Maryland and Delaware might see worsening air quality. Meteorologist Darrius Stringer indicated potential weather changes, such as rain and storms, could alleviate the situation by Saturday.
Officials cautioned that wildfires might persist through summer, potentially worsening air quality intermittently. Smoke combined with extreme heat is creating harmful conditions. Meteorologist Tyler Hasenstein advised remaining indoors to avoid smoke and heat exposure. High levels of fine particulate matter can be detrimental, particularly for sensitive groups.
Those two things coinciding with each other is not good from a health perspective,” Hasenstein stated.
Particulates can worsen respiratory conditions and other health issues. Usage of N95 masks outdoors and maintaining indoor air quality through purifiers or air conditioners is advised.
The Associated Press and Nexstar’s Alix Martichoux contributed to this report. Copyright 2026 Nexstar Media Inc. All rights reserved.