Four States Told To Avoid Exercise This Weekend—'Keep Windows Closed'

Newsweek

12-07-2025

Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.
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Millions of Americans across four states have been urged to stay indoors and avoid strenuous activity this weekend as air quality plummets to dangerous levels and smoke drifts south from massive Canadian wildfires.
The National Weather Service (NWS) has issued air quality warnings in Minnesota, Wisconsin, Colorado and New Jersey, with Minnesotans specifically warned to keep their windows closed through Monday morning.
Why It Matters
Poor air quality puts vulnerable people, including children, older adults, and anyone with heart or lung conditions, at greater risk of serious health problems.
An air quality alert sign is seen as smoke from wildfires burning in Canada reaches Minneapolis on June 3, 2025.
An air quality alert sign is seen as smoke from wildfires burning in Canada reaches Minneapolis on June 3, 2025.
Mark Vancleave/AP
What To Know
The Minnesota Pollution Control Agency has extended its Air Quality Alert through 9 a.m. Monday. The Air Quality Index (AQI) could reach the "Very Unhealthy" or "Purple" category in some regions—meaning even healthy people face a higher risk of harmful effects. A thick blanket of smoke has already moved into parts of the state behind a cold front, with a second, heavier wave expected to spread statewide by Saturday afternoon. Officials recommend everyone, especially sensitive groups, stay indoors, avoid outdoor exercise, and keep windows shut.
"Sensitive groups, such as people with lung disease (including asthma), heart disease, and children and older adults, should avoid all physical activities outdoors. The general public should avoid prolonged or heavy exertion," the NWS said.
"Reduce or eliminate activities that contribute to air pollution, such as outdoor burning, and use of residential wood burning devices. Reduce vehicle trips and vehicle idling as much as possible.
"Keep windows closed overnight to prevent smoke from getting indoors."
In Wisconsin, the Department of Natural Resources has issued an Air Quality Advisory covering nearly every county. Fine particle pollution, or PM2.5, is expected to reach levels from "Unhealthy for Sensitive Groups" to outright "Unhealthy" between early Saturday and noon Monday. Northern areas could briefly hit "Very Unhealthy" levels. Officials urge sensitive groups to move all activities indoors and for everyone else to limit outdoor exertion. Conditions expected to gradually improve on Sunday but remain poor statewide into Monday morning.
In Colorado, the Department of Public Health and Environment has issued an Air Quality Health Advisory for wildfire smoke covering much of southern and western parts of the state, including Rio Grande, Conejos, Mineral, Saguache, Gunnison, La Plata, and San Juan counties. Multiple wildfires are producing moderate to heavy smoke through early Saturday morning. If visibility drops below five miles, residents are urged to limit or avoid outdoor activity entirely. Meanwhile, an Ozone Action Day Alert is in effect for the Front Range Urban Corridor, including Denver and surrounding counties, where hot, stagnant weather is expected to push ozone pollution to levels unhealthy for sensitive groups.
New Jersey has declared a Code Orange Air Quality Alert for parts of the state, including Sussex, Warren, Morris, Hunterdon, Somerset, Passaic, Hudson, Bergen, Essex, and Union counties. Ground-level ozone levels could reach concentrations considered unsafe for children, seniors, and people with asthma or heart disease. Residents in these areas are advised to limit outdoor activities between 11 a.m. and 11 p.m. Saturday and reduce driving and other activities that worsen local air pollution.
Amid the air quality warnings, a group of six Republican lawmakers wrote to Kirsten Hillman, Canada's ambassador to the United States, demanding to know her government's plans for tackling the wildfires. The lawmakers also accused Canada of lax forest management which they say has contributed to "suffocating" smoke.
"In our neck of the woods, summer months are the best time of the year to spend time outdoors recreating, enjoying time with family, and creating new memories," representatives from Wisconsin and Minnesota wrote in the letter. "But this wildfire smoke makes it difficult to do all those things."
Canada's government said it was reviewing the letter and planned to offer a response.
What People Are Saying
The Minnesota Pollution Control Agency said on X, formerly Twitter: "An air quality alert has been issued due to wildfire smoke until 9 a.m. on 7/14. Air quality is expected to reach the purple category, very unhealthy for everyone, in northern MN & will be in the red & orange categories in southern MN."
The Colorado Department of Public Health & Environment said on X: "Ozone will remain in the Good to Moderate range on Friday, but reach the Unhealthy for Sensitive Groups category on Saturday."
The New Jersey Department of Environmental Protection said on X: "An Air Quality Action Day for Ozone has been declared for Saturday, July 12th!
"Sensitive individuals, including the very young, the elderly, and persons with respiratory diseases such as asthma, should avoid strenuous activities during the afternoon and early evening hours. A continued light onshore flow, partly cloudy skies, and warm temperatures are expected. As a result, ozone levels will reach the Unhealthy for Sensitive Groups (USG) category in northern portions of the state, while southern and coastal areas will remain in the moderate range. Fine particulates are expected to drop to low-moderate levels in northern and central New Jersey, and fall to good levels elsewhere."
What Happens Next
Warnings are in place until up to noon on Monday.