"Canadian Wildfire Smoke Engulfs Midwest to East Coast, Threatening Air Quality"

Dense smoke from wildfires in Canada is drifting eastward, affecting the Midwest and East Coast of the United States. Cities such as Detroit, Chicago, and Minneapolis are experiencing some of the worst air quality in the world. Air quality alerts related to wildfire smoke are in effect for parts of 17 states, covering nearly one-third of the U.S. population. The primary pollutants in the smoke are fine particulates known as PM2.5. The smoke is expected to continue drifting east and southeast, worsening air quality in the Mid-Atlantic region. Record high pollution levels have been recorded in several locations, and the pattern of wildfires and smoke is likely to persist due to high-pressure heat domes and climate change.