Canadian wildfire smoke makes Detroit worst AQI globally

A dense plume of smoke from Canadian wildfires has blanketed a vast swath of the United States, creating hazardous air quality conditions across the Midwest and Northeast and making Detroit the city with the worst air quality in the world on Thursday, July 16, 2026. The smoke, originating from numerous out-of-control fires in Ontario and Minnesota, led to widespread health warnings, event cancellations, and reduced visibility from Minneapolis to New York City.

According to air quality monitoring firm IQAir, Detroit recorded an Air Quality Index (AQI) as high as 600 to 724, a level more than double the threshold considered hazardous by the U.S. Environmental Protection Agency. The index measures fine particulate matter, or PM2.5, which poses serious health risks. Other major cities also registered dangerously high readings, with Minneapolis, Toronto, and Chicago consistently ranking among the world's most polluted urban areas throughout the day. Federal data showed dangerous smoke levels across Minnesota, Michigan, northern Illinois, northern Ohio, and into Ontario.

Public health officials responded with urgent advisories, urging residents, especially vulnerable populations, to...