Graphics show how smoke from Canadian wildfires is turning US skies hazy – and hazardous
Smoke from an unusually high number of more than 400 wildfires in Canada is drifting across the U.S. border, turning skies hazy over the Midwest and Eastern states and forcing Americans to take precautions against breathing in harmful pollutants.
Health officials issued warnings about the dangers of breathing wildfire smoke as air quality declined in states from Minnesota to the Carolinas. Public schools in New York City and Washington, D.C., have canceled outdoor activities.
New York and Detroit ranked among cities with the worst air quality in the world as of Wednesday morning, according to IQAir, a Swiss air-monitoring source. New Yorkers were urged to wear pandemic-era masks to protect against the smoke.
Wildfire smoke blankets Eastern US
How hazardous is the hazy air?
Smoke from wildfires is a mixture of gases and fine particles from burning vegetation, building materials, and other materials, according to the Centers for Disease Control and Prevention.
How bad are wildfires in Canada?
In Canada, an estimated 414 fires are burning, 239 of them out of control, according to the Canadian Interagency Forest Fire Centre. Canada has recorded about 2,214 wildfires so far this year, according to Canadian officials. More than 8 million acres have burned, including about 500,000 acres in Quebec.
Fires started in British Columbia and Alberta in late April. Other fires have started in Quebec, Nova Scotia and Ontario, putting a strain on Canada's firefighting resources.
What's causing the wildfires? In British Columbia, officials say lighting causes about 60% of fires while human activity accounts for 40%.
The nation apportions firefighting efforts on the assumption "that only one side of the country will burn at a time," the Globe and Mail reported. That allows provinces to share firefighters and equipment.
Fires on both sides of the country are putting pressure on that system. Canadian officials say higher-than-normal fire activity will continue through September.
Is climate change making Canada wildfires worse?
While it's impossible to say that any one fire or any one season is specifically linked to an increasingly warm planet, the trends show a strong signal, Robert Scheller, a professor of forestry at North Carolina State University, told USA TODAY.
"In some parts of the world, particularly at the higher latitudes towards the poles, the warming is much more accelerated," Howard Diamond, the National Oceanic and Atmospheric Administration's climate science program manager, said in January. He said the global rise in temperature is unmistakable.
Some Canadian officials say climate change is playing a part. “It is a simple fact that Canada is experiencing the impacts of climate change, including more frequent and more extreme wildfires,” said Natural Resources Minister Jonathan Wilkinson in a CTV News report.
Higher temperatures are causing drier conditions that allow forest fires to start. Erratic winds allow the fires to spread, CTV said.
Western Canada can expect a 50% increase in the number of dry, windy days in which fires can start and spread over the next century, a 2017 environmental study says. Eastern Canada could see an increase of 200% to 300%.
US cities' air quality falls as smoke moves in
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CONTRIBUTING Doyle Rice and Elizabeth Weise, USA TODAY
SOURCE USA TODAY Network reporting and research; Associated Press; Centers for Disease Control and Prevention; National Weather Service; IQAir; canada.ca; Canadian Interagency Forest Fire Centre