Brenda Kemmerick was just minutes into her morning walk Saturday in Minneapolis when she sniffed the smoky air from Canadian wildfires, prompting her to don a mask she had previously used to protect herself from COVID-19.

"I usually wouldn't have been wearing a mask outside like this," Kemmerick said as she walked through Lake­view Terrace Park in Robbinsdale. "You're breathing a little heavier and those particles, they say, get in there."

People across Minnesota braced themselves again Saturday to the unsettling idea that simply going outside could be hazardous to their health, as a stifling blanket of soot-filled air from Canadian wildfires continued to hover over the state.

While an air quality alert will remain in effect until noon Tuesday, National Weather Service meteorologist Eric Ahasic predicted air quality will improve by Sunday morning. But that improvement may not last long.

HCMC was seeing an increase in patients coming in with shortness of breath, said John Gallagan, manager of the Respiratory Care and Pulmonary Function Lab. "I couldn't tell you a percentage," he said. "But we've been busy anyway, and this is just creating more business for us."

Gallagan said the risk is greater for older people and children, and for anyone with heart or lung diseases such as asthma, emphysema or chronic obstructive pulmonary disease. Those people should minimize time spent outdoors and carry an inhaler or use a nebulizer, he said.

The smoke was the cause of a few calls to the Minneapolis Fire Department, Chief Bryan Tyner said, from callers complaining about the unusual odor. State Patrol Lt. Gordon Shank said drivers should increase their following distance and turn on their headlights when the smoke affects visibility.

In Canada, 120 fires were reported as of Saturday afternoon in northwest Ontario, with at least 29 not under control, according to Chris Marchand, a spokesman for the fire management center in Dryden, Ontario.

Not only have there been more fires to date this season in that part of Ontario — 843, compared with the 10-year average to date of 572 — but they've been bigger and generated more smoke, he said. More than 1.5 million acres have burned in northwest Ontario, nearly four times more than usual.

Spotty showers in Ontario and Manitoba on Friday night did little to arrest the smoke from the wildfires north of the border, and the short-term forecast is not encouraging. "Until that deep underground gets the soaking it needs, we are going to be doing the status quo here," Marchand said.

Officials said they expect smoke from the Canadian fires to continue blowing into the state on Sunday and recirculate Monday into Tuesday under a high-pressure system. Southerly winds should move the smoke out Tuesday.

Ryan Stauffer, an air pollution researcher at NASA, said the smoke engulfing Minnesota is remarkable for its proximity to the ground, as well as other qualities. On Thursday, a day when many metro area residents noticed the heaviest smoke, dangerous air particles — those with a diameter smaller than 2.5 microns — were recorded at the highest level since data collection began in 1999, he said.

'You couldn't see 200 yards'

While some outdoor activities continued as planned in the metro area, many people were thinking twice about spending a lot of time outside. Others, like Kemmerick, were adjusting their daily routines.

The Loring Park Art Festival made its return after being canceled last year because of the pandemic. Hundreds went from tent to tent browsing through paintings, sculptures and jewelry. "People are excited to be out," said Sue Holmquist of Northfield, who was selling pottery.

She and her husband, Chris, were happy to be in the Twin Cities, where they said skies were clearer than at their home in the Northfield countryside. "This is more blue than we've seen in days," Sue Holmquist said.

At Theodore Wirth Regional Park, dozens were golfing and taking the mountain-bike trails. The smoke didn't bother Minneapolis resident Sam Olson, who was mountain biking with his son, but he said it did affect the family earlier in the week.

They had to leave their cabin south of the Canadian border early because "the smoke was so thick you couldn't see 200 yards, and it smelled like a campfire," said Olson, who has asthma.

Jesse Berman postponed plans to go biking with his kids this weekend. "I don't want to be out there and have my kids out there breathing smoky air for an extended period of time," said Berman, assistant professor of environmental health sciences at the University of Minnesota's School of Public Health.

Young, healthy adults can probably spend time outside without symptoms beyond a cough or scratchy throat, Berman said. But they should avoid strenuous activities that cause heavy breathing, which pulls more particles into the lungs and bloodstream.

He recommends that people stay indoors as much as possible.

"Air conditioning and HVAC systems actually do a pretty good job of filtering out the [smoke] particles," he said. "Try to avoid opening your windows later in the afternoon in the heat of the day."

Summer outlook

People with COVID are also at extra risk, along with those who smoke or use inhaled chemicals, Gallagan said. A two-layer cloth mask of the kind worn to protect against COVID can protect the lungs from smoke outdoors, he said.

Research is still underway, but it's possible that those who have had COVID may be more vulnerable to wildfire smoke. Experts are gathering information about the virus' long-term effects.

"We're still in the beginnings of this to see what it looks like on the other side," Gallagan said. "Unfortunately, we don't have a really clear answer right now."

According to Ahasic, until the wildfires in the West and Canada ebb, smoke will linger through the summer. "We'll have to see how it goes as we head into [this] week," he said.

Staff writer Patrick Kennedy contributed to this report, which includes material from the Washington Post. 612-673-4234 • Twitter: @ryanfaircloth 612-673-4583