A smoky summer is expected in parts of Canada as wildfire season begins. Here's how to prepare now

People in southern Ontario should start preparing now for the potential of smoke hanging over this part of the province during the upcoming wildfire season, one researcher says.

"The most important thing is to act early," Amy Li, an assistant professor in the department of civil and environmental engineering at University of Waterloo, told CBC Kitchener-Waterloo's The Morning Edition.

She suggested taking two important steps:

• Make sure a home's centralized HVAC system can recirculate the indoor air for heating and cooling and have high-efficiency filters.
• Consider purchasing portable air cleaners that arean appropriate size for the space you want to clean.

With wildfires will come warnings about PM 2.5, which is the particulate matter in smoke, Li said. The small particles have a diameterequal to or smaller than 2.5 micrometres.

"As you can imagine, this is really small and exposure to elevated concentrations of PM 2.5 can cause adverse effects to the respiratory system and also the cardiovascular system and especially for vulnerable populations including children, people with respiratory disease or older people," Li said.

She noted on any given day in Waterloo region, the PM 2.5 concentration would be between five and20 or 25 micrograms per cubic metre.

During some of the smokiest days in 2023, southern Ontario saw 250 micrograms per metre cube, "even close to 300 microgram per meter cube."

That happens even though the fires aren't necessarily in southern Ontario.

"Particles are so small, so they can remain suspended in air for a very long time. And then with the right or maybe the wrong wind condition, they can travel a very long distance. And that's why the pollutant concentration is high even if the wildfire is not in our region," Li said.

Fire season officially underway in Ontario

Ontario's fire season officially started Mondayand runs through Oct. 31.

Following Canada's worst wildfire season on record last year, experts and community leaders across northwestern Ontario have expressed concerns about how the 2024 season will play out.

The province reported more than 700 fires and 441,000 hectares of forests burned between April and October 2023 almost three times as many hectares as the 10-year average.

Ontarians should expect a more active wildfire season this summer because of the milder winter, saidAnabela Bonada, manager and research associate at the Intact Centre for Climate Adaptation at the University of Waterloo.

"We didn't have much of a snow pack out here in Ontario, especially in southern Ontario, and that means our ground is not as protected and it's not getting as much moisture," she told CBC News.

"We have more dry debris on the ground and if there's any lightning or any sort of human-caused ignition, we could end up with quite a bit of wildfire this summer."

She added that in 2023, wildfires got an early start in the western part of the country because of a "very hot and intense start to the spring."

This "led to the conditions that were just perfect for that extreme wildfire season."

Temperatures are expected to be milder than usual in Ontario this spring, she said.

"Now it's just a matter of what kind of precipitation we'll get," she said.

LISTEN|University of Waterloo climate adaptation expertAnabela Bonada tells us whatto expect duringwildfire season:

The Morning Edition - K-W5:58As we head into Ontario's wildfire season, University of Waterloo climate adaptation expert, Anabela Bonada tells us what to expect

April is the start of wildfire season in Ontario. Considering the devastation we experienced last summer, what can we expect for this summer? We hear from an expert in climate adaptation from the University of Waterloo about what to expect this summer

Early start to fire activity expected

Brian Simpson, a scientist with the Canadian Forest Service, told CBC News in an email that seasonal forecasts for May and June show above-average temperatures across the country.

"Therefore, we anticipate an early start to the fire season and more widespread fire activity than usual," he said.

It is hoped a three-day winter storm in parts of northern Ontario last week, though, will delay the start of the season for a bit.

Chris Marchand, fire information officer at the Northwest Region Fire Management Centre in Dryden, told CBC News the "significant addition of moisture" will help for a bit.

"But fire's a weather-driven phenomenon, so it all depends on how the weather that we get preserves that snow cover or takes it away from us," Marchand said.

"Eventually, the moderating effect of the snowfall on the spring fire hazard will wear off as snow cover retreats as we move into April, but we will be monitoring that across the region as we move through the next couple weeks."