Overview
- Smoke from hundreds of Canadian fires pushed PM2.5 to very unhealthy and hazardous levels on Friday, placing more than 100 million people in parts of the Midwest, Great Lakes, Northeast and Mid‑Atlantic under air‑quality alerts.
- Real‑time monitors listed Detroit, Chicago and Minneapolis among the world’s worst cities for air quality, with IQAir showing readings that reached hazardous levels in multiple urban areas.
- Local and state officials distributed N95/KN95 masks, closed outdoor pools and beaches, opened cooling and clean‑air centers, and urged people to stay indoors or avoid vigorous outdoor activity.
- Forecasters said a cold front and possible storms could thin or move the plume temporarily, but they warned that wind shifts and hundreds of active fires—many out of control—could cause smoke to recirculate over the weekend.
- Health agencies stressed that wildfire smoke carries fine particles (PM2.5) that penetrate deep into lungs and the bloodstream, driving spikes in respiratory and chest complaints and raising risks for older adults, children and people with heart or lung disease.