Smoke from over 700 active Canadian wildfires, part of the country's second-worst wildfire season, has caused poor air quality across the U.S. Midwest and Northeast. States including Wisconsin, Michigan, Minnesota, Illinois, Indiana, New York, Vermont, New Hampshire, and Maine are under air quality alerts, with some experiencing the longest such alert on record. Health officials warn of respiratory issues, and the poor air quality is expected to persist this week due to prevailing wind patterns.

Prepared by Olivia Bennett and reviewed by editorial team.