Canadian Wildfires Spark Hazardous Air Alerts Across US

Thick smoke from hundreds of wildfires burning across Canada has triggered widespread air quality alerts across the United States, blanketing the Midwest and Northeast with hazardous pollution. The smoke, originating primarily from out-of-control blazes in western Ontario, began deteriorating air quality on July 15 and intensified through July 17, prompting official health warnings for millions of residents.

Air Quality Index values soared into the hazardous category, surpassing 250, in numerous major cities. Chicago registered an exceptionally high AQI of 342, while Washington, D.C., Pittsburgh, Cleveland, and Detroit also recorded dangerous levels. Official alerts were enacted for Delaware, Maryland, Michigan, New Jersey, Ohio, Pennsylvania, and Wisconsin, with additional warnings across Minnesota, New York, and parts of New England. Health experts warned the fine particulate pollution poses immediate and serious health risks, particularly for children, older adults, and people with heart or lung conditions.

Officials have advised the public to suspend outdoor activities, stay indoors where possible, and wear N95 or KN95 masks if going outside is necessary. A medical official...