Canadian Wildfire Smoke Continues To Make Air Hazardous

· Thick, pungent smoke from wildfires in Canada and northern Minnesota darkened skies across the U.S. again yesterday, from the Great Lakes to parts of the East Coast, reducing visibility and prompting warnings that being outside could be dangerous

· More than 120 million people across a dozen states were under air quality alerts, and Detroit ranked among the worst major cities in the world for air quality as a high-pressure system trapped smoke from dozens of fires

· Detroit, Minneapolis, and Chicago all landed in the top five most polluted major cities yesterday

· All of Michigan and much of Minnesota fell under hazardous air quality alerts, the most severe category, which puts sensitive groups like children, the elderly, and those with heart or lung problems at particular risk

· The smoke came as more than 100 wildfires burned across Canada, and at least 17 raged in northern Minnesota, including three in the Boundary Waters Canoe Area Wilderness

· Source: NBC News