Overview

• Air quality alerts remain in effect across Illinois through Saturday at midnight and extend into Wisconsin, Minnesota and Michigan as dense smoke drifts south from Canadian wildfires
• Chicago’s AQI has dropped from “unhealthy” to “unhealthy for sensitive groups” yet continues to surpass EPA safe limits after briefly ranking worst globally on Thursday
• The Illinois EPA and National Weather Service have declared Air Pollution Action Days, advising children, older adults and people with heart or lung conditions to limit outdoor exertion
• Experts warn that fine particulate matter (PM2.5) infiltrates homes more easily than assumed and recommend running HEPA air purifiers or MERV-13 filters in HVAC systems
• Forecasts call for only gradual clearing over the weekend as high-pressure systems trap smoke near the surface, and residents are urged to monitor AirNow for evolving conditions