Open this photo in gallery Students from Lord Beaverbrook school celebrate their graduation with a photo in front of the smokey city skyline in Calgary on May 31, 2019. Todd Korol/The Globe and Mail

Street lights blinked on in the midday gloom, schools kept children indoors and people with respiratory conditions were told to shut the windows or seek reprieve in shopping malls and libraries, if they went out at all.

Thick smoke from Alberta wildfires has reduced visibility in large cities and fouled air across much of the province this week, triggering health warnings and adding an urban dimension to a disaster that has already prompted scores of evacuations in northern communities and put many more on high alert.

Air-quality advisories were issued on Friday for Calgary and extended for Edmonton as the number of wildfires classified by the province as out of control grew to nine. Environment and Climate Change Canada said conditions could remain hazy into the weekend as heavy smoke blanketed a region from northeastern British Columbia down to southern Alberta.

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Smoke warnings and air advisories in Western Canada are an increasingly common symptom of wildfires that scientists say are growing more extreme as a result of climate change.

Alberta Premier Jason Kenney, however, says forest fires have always been around and carbon taxes won’t do anything to change that. His United Conservative government repealed the province’s carbon tax this week to make good on an election campaign promise.

Mr. Kenney shrugged off criticism that Alberta is now doing less to fight climate change.

“They’ve had a carbon tax in British Columbia for 10 years. It hasn’t made a difference to the pattern of forest fires there … or in Alberta. And we’ve always had forest fires. We always will,” the Premier said on Friday after a luncheon speech to a Calgary business audience.

“We have huge patches of very old, boreal forest where there have not been fires for, in some cases, 80 or 90 years. All of the forestry experts will tell you that these regions of Alberta have been overdue for a major forest fire and our forests have been growing older.”

Federal Public Safety Minister Ralph Goodale says Alberta has asked for Canadian Forces assistance and the federal government has accepted the request. Mr. Goodale says the military will be ready to help airlift evacuees as needed, as well as transport supplies and provide medical assistance.

In Calgary on Friday, the city skyline was shrouded in a thick haze and Environment Canada’s air-quality health index (AQHI) topped 10, indicating very high risk.

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A day prior, Edmonton streetlights and buildings lit up hours before nightfall and pockets of the city saw measures of dangerous particulate matter spike to levels well above Alberta’s ambient air-quality thresholds.

“It changes everything," said Gary Redmond, executive director of Alberta Capital Airshed, a community organization that monitors and analyzes air quality in the Edmonton area. “If you go outside, you immediately feel like you’re in very close vicinity to a wood fire. That’s all you can smell. You can feel it into your lungs immediately. And the dimness of the light is quite significant.”

By Friday, officials said the Chuckegg Creek fire near High Level, Alta., had grown to more than 2,300 square kilometres. Near Slave Lake, Alta., a separate fire had spread to more than 1,800 square kilometres, prompting officials to declare an eight-hour evacuation notice for the community. Slave Lake was the site of a devastating fire as recently as 2011.

This year marks the third one in a row that Alberta has been inundated, following consecutive years in which smoke from record-breaking fires in British Columbia’s Interior drifted east across the Rockies.

Environment Canada meteorologist Dan Kulak said air quality in both Edmonton and Calgary is forecast to improve over the weekend but conditions will remain poor barring a broad shift in weather. “We need some rain, essentially," he said.

He said satellite images already showed wildfire smoke had drifted east to as far as Minnesota and into Ontario. However, that does not necessarily mean it poses a health threat. “The heaviest blob of smoke is probably going to stay in the central part of the province where the fires are,” he said.

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The long-term impact of smoke events can be pronounced, said Joe Vipond, an emergency physician based in Calgary and the Alberta regional committee chairman with the Canadian Association of Physicians for the Environment.

He said he saw people with asthma last fall who told him they had not recovered from the previous summer’s wildfire-smoke events. He added such impacts are being felt at the same time the Alberta government dismantles policies aimed at tackling climate change.

“This is a sad irony that we are disposing of climate policy at the same time where the urgency of this problem is becoming more and more evident," Dr. Vipond said.

With a report from The Canadian Press