Smoky haze blanketing U.S., Canada could last for days as wildfires rage, winds won't budge

The weather system that’s driving the great Canadian-American smoke out “will probably be hanging around at least for the next few days.”

On air quality maps, purple signifies the worst of it. In reality, it's a thick, hazardous haze that’s disrupting daily life for millions of people across the U.S. and Canada, blotting out skylines and turning skies orange.

And with weather systems expected to hardly budge, the smoky blanket billowing from wildfires in Quebec and Nova Scotia and sending plumes of fine particulate matter as far away as North Carolina should persist into Thursday and possibly the weekend.

That means at least another day, or more, of a dystopian-style detour that's chased players from ballfields, actors from Broadway stages, delayed thousands of flights and sparked a resurgence in mask wearing and remote work — all while raising concerns about the health effects of prolonged exposure to such bad air.

The weather system that's driving the great Canadian-American smoke out — a low-pressure system over Maine and Nova Scotia — "will probably be hanging around at least for the next few days,” U.S. National Weather Service meteorologist Bryan Ramsey said.

“Conditions are likely to remain unhealthy, at least until the wind direction changes or the fires get put out,” Mr. Ramsey said. “Since the fires are raging — they’re really large — they’re probably going to continue for weeks. But it’s really just going be all about the wind shift.”

Across the eastern U.S., officials warned residents to stay inside and limit or avoid outdoor activities again Thursday, extending “Code Red” air quality alerts in some places for a third-straight day as forecasts showed winds continuing to push smoke-filled air south.

In Washington, D.C., Mayor Muriel Bowser ordered schools to cancel outdoor recess, sports and field trips Thursday. In suburban Philadelphia, officials set up an emergency shelter so people living outside can take refuge from the haze.