About two thirds of Wisconsin is under an air quality advisory due to smoke from Canadian wildfires, according to the state’s Department of Natural Resources. 

A map from the DNR shows much of central Wisconsin has air quality considered “unhealthy for sensitive groups,” including people with heart or lung disease, older adults and children. 

Eau Claire and Marathon counties have air quality considered unhealthy for everyone, according to the map. 

The advisory is expected to expire at midnight. 

This is the first air quality advisory of the season, and it comes about a week earlier than last year. In 2023, Canadian wildfire smoke spurred the most air quality advisories Wisconsin had seen in more than a decade. 

DNR Air Management Program Outreach Coordinator Craig Czarnecki told WPR that before last year, it had been about a decade since the state issued an advisory regarding wildfire smoke during the spring. 

“It’s been quite a while since we’ve seen impacts like this in the spring. That’s two springs here in a row,” Czarnecki said. 

It remains too early to tell if we will again see intense episodes of orange skies and the persistent smell of smoke that blanketed much of the state last summer. The haze got so thick last June the state issued its first “very unhealthy” advisory.

“One thing we do know right now is much of Canada does remain in those drought conditions, including some areas of extreme drought which is where some of those fires are located up in British Columbia right now,” he said. 

Canada had 145 active fires burning on Monday, according to the Canadian Interagency Forest Fire Centre.

“What happened is presumably the wildfires that were going on in Canada might not have been fully put out by their snowpack, and so they can reinvigorate in the springtime,” said Marcia Cronce, a meteorologist with the National Weather Service in Milwaukee. 

“If you are able to view the sun, you’ll notice that it’s kind of a milky appearance in the sky in a little bit of filtered sunshine. It might appear a little bit more orange,” she said. 

The DNR issues air advisories when levels of tiny particles or ozone in the lower atmosphere reach unhealthy levels. 

Eau Claire has an Air Quality Index of 152, while Marathon is at 175, according to the DNR’s map. The higher that number, the more dangerous conditions are. The United States Environmental Protection Agency says an Air Quality Index of 101 to 150 can be unhealthy for those with some health conditions,  while 151 to 200 is unhealthy for the general public.

“We have a little bit higher concentrations of particulate matter and that can irritate people that are susceptible to problems like asthma or heart or lung disease, older adults or children,” Cronce said. “So try to stay indoors if you fall into that category.” 

Czarnecki said N95 masks can also help limit some of the impacts from wildfire smoke. The DNR has a website devoted to air quality resources.