News Chicago and Detroit have the worst air quality in the world due to Canadian wildfires. Here’s how to stay safe. June 27, 2023Jeanine Santucci and Thao Nguyen, USA TODAYComments Off on Chicago and Detroit have the worst air quality in the world due to Canadian wildfires. Here’s how to stay safe. Three U.S. cities ranked among the top 10 for worst air quality in the world Tuesday morning as smoke from Canada fires hit Chicago and the Midwest.