Air quality alert: Breathing is not guaranteed as smoke from Canada’s infernos chokes cities from Toronto to New York

After days of a heavy grey haze blanketing southern Canada, air‑quality alerts were lifted across most of Québec and Ontario on Sunday, June 8.

Environment Canada reported that a shift in wind patterns and light rainfall pushed smoke eastward, lifting warnings over major cities like Toronto, Ottawa, and Montréal, but pockets of poor air remain east of Montréal, south of Québec City, and in northern Ontario toward the Manitoba border

How it all started

Over 200 active wildfires in Manitoba and Saskatchewan churned out massive smoke plumes since early June, forcing thousands to evacuate and creating hazy skies across six provinces and the Northwest Territories.

Those plumes raced across Canada and into the Eastern US, sparking health alerts in New York and parts of the Midwest.

The science of the smoke

Wildfire smoke is rich in PM2.5, tiny particles that penetrate deep into the lungs and the bloodstream.

Researchers warn that even brief exposure can trigger asthma attacks, heart problems, and headaches, while cumulative exposure may increase risks of lung cancer and stroke. Some scientists have also raised alarms about toxic metals like arsenic and lead, released when fires spread through mining‑contaminated soils, intensifying long‑term risks.

The human toll

For north Toronto kindergarten teacher Emily Chan, the sky "smelled like burning plastic," and many of her students complained of sore throats. She recalled, “We kept windows shut and cancelled outdoor playtimes.”

In Montréal, retiree Marc Lecavalier said he felt his chest tighten during walks on the Île de la Cité, opting instead to sit inside with filtered air.

Across the US border, in upstate New York, air‑quality warnings persisted on Sunday despite slight improvements, with the Adirondacks reaching an AQI of 150, "unhealthy for sensitive groups," while Finger Lakes briefly hit levels considered unhealthy for all.

What’s next

Environment Canada expects a low‑pressure system to move through the Prairies and into Manitoba and northwestern Ontario by Monday, and bring much-needed rain to douse the fires. But as long as wildfires continue, the risk remains.

Health officials still advise those in affected zones to stay indoors, avoid strenuous activity, and wear N95 masks if they must go outside.

Experts predict smoke events will become more frequent and severe as climate change fuels longer fire seasons. For now, Canadians and Americans are getting a reminder: clean air isn’t guaranteed.