A thick, toxic cloud of smoke has blanketed parts of the US on Monday, sparking air quality emergencies in three states.
Residents in Michigan, Minnesota and South Carolina have been issued the alert, urging them to stay indoors today and possibly Tuesday.
Authorities warned that smoke from more than 160 active wildfires in Canada is drifting southward, creating a public health emergency across several US regions.
The National Weather Service issued alerts cautioning that fine particles in the air known as PM2.5 has risen to unsafe levels.
PM2.5, fine particles less than 2.5 micrometers wide about 30 times smaller than a human hair. It can easily penetrate deep in the lungs and even enter the bloodstream, causing inflammation, heart issues and worsening asthma symptoms.
Children, the elderly and people with asthma and heart disease are especially at risk.
In Michigan and Minnesota, the problem is largely due to smoke pouring in from blazes in Manitoba and Saskatchewan, driven south by strong wind and cold front.
Meanwhile, parts of South Carolina are experiencing a separate but related threat, high ozone pollution levels, worsened by weekend smoke interactions
Officials advised locals to limit the outdoor activities, close windows and use filtered air indoors to avoid potentially serious health effects.
Wildfire smoke contains a mix of gases and fine particles that can trigger respiratory problems and exacerbate chronic health conditions.
On Monday, a broad air quality alert was in place for most of Minnesota, as smoke from Manitoba and Saskatchewan wildfires continued its slow march south.
The pollution stems from Canada's escalating wildfire crisis, which officials say is on track to rival or exceed last year's record-breaking season.
'Sensitive groups should avoid prolonged outdoor exertion,' the alert said, adding that even healthy individuals may feel effects during peak hours.
In Michigan, the Department of Environment, Great Lakes, and Energy (EGLE) issued an advisory affecting 15 counties, including Keweenaw, Delta, Marquette, Iron, and Houghton.
Conditions were expected to remain unhealthy for sensitive groups through late Monday and potentially into Tuesday morning.
The warning coincided with a Red Flag Warning in effect until 10pmET/9pm CST in western Upper Michigan, where hot, dry, and windy weather created prime conditions for fire spread.
Temperatures near 90°F and humidity levels below 30 percent meant any spark could lead to a rapidly spreading blaze.
'Any fire that develops will catch and spread quickly,' the National Weather Service in Marquette posted. 'Campfires, outdoor grills, smoking materials, fireworks, chain saws, and all-terrain vehicles all have the potential to throw a spark and ignite a dangerous and destructive fire.'
Meanwhile, The South Carolina Department of Environmental Services (SCDES) has issued a Code Orange Ozone Action Day for the Catawba and Upstate regions, including cities like Greenville and Spartanburg.
The warning comes as stagnant air, low wind speeds, and high temperatures are expected to cause elevated levels of ground-level ozone, worsened by wildfire smoke drifting from Canada.
'These conditions create a perfect storm for ozone pollution, especially dangerous for people with asthma or other lung diseases,' said an SCDES spokesperson.
The danger isn't limited to just these three states.
Experts warn that hazy skies and low-level smoke could stretch as far south as Illinois, Indiana and Ohio, and as far east as the Mid-Atlantic in coming days.
Satellite imagery over the weekend showed a thick blanket of smoke reaching from the Dakotas to the Great Lakes.
AccuWeather meteorologist Brandon Buckingham noted that the smoke will vary in intensity.
'Most of the time it will hover high in the atmosphere and just dim the sun, but there will be episodes where it sinks to ground level,' Buckingham said.
That drop makes the air dangerous to breathe, especially for people with pre-existing respiratory issues.
In Manitoba, Premier Wab Kinew declared a state of emergency last week and ordered evacuations of over 17,000 residents from communities near large fire zones.
'This is the largest evacuation Manitoba will have seen in most people's living memory,' Kinew said. The Canadian military has been called in to assist.
While experts say 2025's wildfire smoke hasn't yet matched last year's historic haze, which famously turned New York City skies orange, they warn the season is still in its early stages.
Peak wildfire activity in Canada typically occurs between late June and early August.
In response, many public health agencies are recommending that households use HEPA or MERV-13 air filters, avoid strenuous outdoor activity, and consider wearing N95 masks if they must be outside in areas with visible haze.
The Environmental Protection Agency (EPA) continues to update its https://www.airnow.gov/ portal with real-time air quality data for communities across the U.S.
