Winds are pushing smoke from Canadian wildfires into major cities across the U.S. Midwest and East Coast.
The smoke is causing dangerous air quality levels in both countries.
The wildfires are burning over 400,000 hectares across Canada.
They stretch from the western provinces all the way to the eastern provinces of Quebec and Nova Scotia.
Canadian officials have expanded evacuation orders and asked other countries for help fighting more than 420 fires nationwide.
Winds are blowing smoke from Eastern Canada to the south, causing people in places like New York City, Washington, D.C. and Philadelphia, Pennsylvania, to see hazy skies.
Officials in many cities have sent out air quality warnings and urged people to limit time outside.
The U.S. Environmental Protection Agency said the smoky air and the smell of burning wood are likely to stay around for a few more days in northern states.
Darren Austin is a weather expert with the Rhode Island Department of Environmental Management.
He said the small eastern state sometimes sees smoke in the air from wildfires.
However, by the time the smoke gets to his state, it has often spread over a large area.
This time, the fires are much stronger and only about 800 kilometers away.
Dr. David Hill is a breathing and lung expert based in Connecticut.
He said this kind of smoke contains small particles that can get into the lungs and cause health problems.
Trent Ford is a weather expert in the Midwestern state of Illinois.
He said the recent dry and windy conditions in many places across the country have made it easier for the smoke to travel longer distances.
Rain would have made the air heavier and cleaner.
The American Lung Association notes that smoky air can be a problem for young children because they breathe in more air relative to their body weight than adults.
Hill, the lung expert, said people who will be working outside for a long period of time should consider wearing a face mask.
The ones people wore during the COVID-19 pandemic – rated N95 or similar- will help.
In addition, he advised people to check their home air filters and consider purchasing an air purifier.
I'm Dan Friedell.