Wildfire Smoke Severely Impacts Air Quality in U.S. Cities, Triggering Health Alerts
In mid-July 2026, wildfire smoke originating from eight fast-growing fires in northwestern Ontario severely affected air quality across the U.S. Midwest and Northeast. Cities like Duluth, Minnesota, experienced unprecedented levels of fine particulate matter (PM2.5), with readings reaching hazardous levels. The smoke wave, lasting from July 14 to 19, saw 21 of the 25 hardest-hit U.S. metro areas averaging PM2.5 levels above the EPA's 'Unhealthy for Sensitive Groups' threshold. The smoke's impact extended to cities far from the fires, including New York and Washington, D.C., highlighting the widespread nature of the air quality emergency.