Wildfire smoke from more than 100 active blazes in Canada continued to drift southward on Thursday, creating widespread haze and unhealthy air conditions across the U.S. Midwest and Northeast. The Canadian government reported numerous uncontrolled fires fueling heavy smoke plumes that have substantially reduced visibility and degraded air quality in multiple states.

The Environmental Protection Agency (EPA) issued air quality alerts covering large portions of the Northeast and Great Lakes regions, warning of hazardous levels of fine particulate matter in the air. These tiny particles, capable of penetrating deep into the lungs and eyes, pose health risks including eye irritation and respiratory difficulties, especially for sensitive groups such as children and the elderly. The EPA advised limiting outdoor activities to reduce exposure.

The air quality index (AQI), which ranges from 0 to 500, reached near 150 in New York by Thursday afternoon—categorized as unhealthy for everyone. Chicago registered an extreme reading of 597, a level indicating severe air pollution and significant health concerns. This is attributed to the dense concentration of smoke particles trapped by stagnant weather patterns.

A persistent heat wave affecting the region has contributed to the smoke accumulating near the ground. The National Weather Service forecasted elevated heat risks stretching from North Dakota to Washington, D.C. on Friday, conditions which also inhibit the dispersion of airborne pollutants.

Scenes of hazy skies were reported across multiple locations, including Silver Beach in St. Joseph, Michigan, and over Lake Michigan, where the haze reduced visibility significantly. Authorities continue to monitor the situation closely as smoke from the Canadian wildfires threatens to impact air quality for at least the remainder of Friday.