As Canadian wildfires spread smoke across the U.S. the air pollution is dangerous to health. But there are ways to protect yourself. Here's what to know.
Wildfire smoke is like smoking 'half a pack a day.' Here's how to protect yourself
toggle caption Liao Pan/China News Service/VCG via Getty Images
This story is updated to reflect the current wildfire smoke conditions in the U.S. The original story w... [5764 chars]