Overview

• Minnesota and Michigan remain under statewide air quality alerts through Friday with particulate levels reaching the red, or unhealthy for all, category.
• All of Wisconsin and parts of Pennsylvania including Lehigh Valley, Berks and the Philadelphia metro area are under orange-level warnings for sensitive groups.
• Health officials urge people with heart or lung conditions to avoid strenuous outdoor activity, keep windows closed and run high-efficiency (MERV-13 or higher) air filters.
• Smoke stems from more than 550 wildfires burning over 15 million acres in Manitoba and Saskatchewan, driven by this summer’s extreme heat and drought.
• A cold front due Friday will bring rain with strong winds that are forecast to disperse the smoke and improve air quality by the weekend.