A wave of smoke from Canadian wildfires has prompted air quality alerts in multiple states, including Wisconsin, Michigan, Iowa, and Minnesota. Major cities like Chicago and Milwaukee report some of the worst air quality in the world, impacting millions of residents. Alerts indicate unhealthy air conditions, leading to recommendations for individuals to monitor for symptoms such as coughing and dizziness. Authorities have kept advisories in effect, with predictions of gradual improvements over the weekend. As smoke continues to blanket the region, residents are advised to take precautions and stay indoors when possible, especially children and those with respiratory issues.