Wildfires causing air quality issues in many cities across Canada and U-S

Canadian cities are being smothered in heavy wildfire smoke, with air quality degrading for millions.
Experts are advising those living in areas with dense levels of smoke to avoid going outside if possible, as the small particles in wildfire smoke can irritate the eyes, nose and throat, while also affecting the heart and lungs, making it harder to breathe.
Health Canada says the people at highest risk of harm from bad air quality include those with respiratory or heart problems,  as well as infants, young children and seniors.