Canadian wildfires are causing poor air quality in the northeastern U.S., posing a health danger to millions of people. Experts say the air is especially harmful for more vulnerable populations, including older people and those with lung or heart issues.
The best thing to do to protect yourself? Stay inside and take other precautionary steps to limit your exposure, experts say.
"The particulate matter that's in this haze is significant because it does irritate the bronchioles, or the small tubes that go down into your lungs and connect to the alveoli, which are the sacs that allow you to breathe," Dr. Bob Lahita, director of the Institute for Autoimmune and Rheumatic Disease at St. Joseph's Health, told CBS News. "That gets irritated in people without asthma, but if you have asthma, chronic obstructive pulmonary disease, congestive heart failure or anything that involves your lungs or even your heart, you should stay indoors."