Toronto's air quality 'much worse' from wildfire smoke Thursday, but meteorologist expects reprieve tonight

A thickly, smoky haze blanketing the Greater Toronto country is " often worsened" compared to the broadcast quality levels seen over the past few days, said a meteorologist with Environment Canada.

An orange-level air quality warning is still in place Thursday, as drifting smoke from forest fires in northwestern Ontario is causing poor air quality and reduced visibility for much of southern Ontario, according to the national weather agency.

Environment Canada warned that everyone's health, regardless of age or condition, was at risk due to heavy smoke conditions. It urged people to cancel outdoor events and to wear a "well-fitted and properly worn" mask, such as an N95, to reduce exposure to fine particles in the smoke.

Meteorologist Peter Kimbell said there is more fine particulate matter, also known as PM 2.5, in the air from the smoke compared to the last two days in Toronto. These airborne particles are less than 2.5 micrograms in diameter, which is smaller than a strand of human hair, and can travel deep into your lungs.

He said there was about 300 micrograms/metre of PM 2.5 in the air Thursday, whereas on Wednesday there was about 90 to 100 micrograms/metre.

"So we seem to be in a spike right now that is pretty, pretty bad and that may last for a few hours yet before conditions improve this evening," said Kimbell.

Normally the level of PM 2.5 should remain below 30 micrograms/metre and anything above 60 micrograms/metre is concerning enough to issue a warning, he said.

The air quality health index (AQHI) across the GTA, including Mississauga, downtown Toronto and Oshawa, was at 10+ or at "very high risk" as of 9 a.m. Thursday. On Wednesday, AQHI levels were at 10+ until noon and then decreased down to 7 through the day.

Toronto ranked second on Thursday morning in a list of the world's most polluted cities, according to a global ranking by IQAir, a Swiss air quality technology company. For some time on Wednesday, the city was first before dropping down in the ranks.

Some improvement in the air quality is expected Thursday night and Friday as winds change direction to head southwest away from the GTA, said Kimbell.

"Things may get worse again" as smoke is expected to come back on Friday night, but hopefully will not last long due to forecasts for rain on Saturday, he said.

"It's basically going to be up and down, but generally speaking it should be an improvement."

What you need to know about wildfire smoke blanketing Toronto

Dr. Michelle Murti, Toronto’s medical officer of health, said her eyes "started burning" as soon as she stepped out the door this morning.

People should get used to seeing smoke or other impacts from wildfires in the near future, said Jeffrey Siegel, a University of Toronto professor who researches air quality.

"I believe that this is the new normal, the data shows that very, very clearly," he said, adding the province and municipalities should develop more strategies to mitigate impacts to health.

Siegel said there is no safe suggestion for how much time people can spend outdoors. But anyone venturing out should wear a mask and limit physical activity.

"This is obviously not a good time to exercise outside for all of us, healthy and otherwise," he said.

Murti warned that extended exposure to smoke over time can exacerbate health conditions like asthma and increase the risk for cancer, dementia and neurodevelopmental delays in children.

Environment Canada warned residents may experience symptoms including headaches, eye and throat irritation, wheezing or chest pains.

Seniors, pregnant people, young children, people who work outdoors and those with existing health conditions are more likely to be impacted by the wildfire smoke. They're advised to avoid going outdoors and to seek medical attention if experiencing symptoms.

For those staying indoors, the weather agency advised on keep windows and doors closed as much as possible.

Several people took to social media early Thursday morning to note the smell of smoke inside their homes. That is not unexpected, said Siegel, but noted there are ways to reduce the smell and any impacts.

He advised people with a central forced air system to have the fan running and to ensure a good filter is in place. Anyone without that system can either purchase or build their own portable filter, he said.

Murti said people should avoid turning on exhaust fans and to set ventilation systems to recirculate air. She also recommended people dig out air purifiers they may have purchased during the COVID-19 pandemic.

How Toronto's wildfire smoke and air quality are impacting the city's most vulnerable

Toronto the orange: Wildfire smoke leaves city under dirty sky with no relief likely until Friday

All city-run outdoor pools will remain closed Thursday closed mid-afternoon due to the air quality, Toronto said in a bulletin Wednesday afternoon. CampTO trips and outdoor programs have also been cancelled, the city said.

Toronto has also has opened six "cleaner air spaces" at City Hall, Metro Hall, North York Civic Centre, Scarborough Civic Centre, York Civic Centre and East York Civic Centre.

Murti said the city has tested the air quality in all of those locations to ensure smoke is being properly filtered out.

Peel Public Health also issued a warning Wednesday, adding residents staying indoors should avoid smoking, vaping, frying foods and vacuuming to reduce air pollution inside.

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