Chicago's Air Quality Hits AQI 342 as Wildfire Smoke Blankets the Midwest

It is another day of dangerous air quality conditions for millions of Americans living in the Upper Midwest, the Great Lakes, and the Northeast. What parts of the U.S. are seeing the worst air on Friday? Here is what you need to know.

Dangerous Air Quality Conditions Across Several Major U.S. Cities

The zone from Chicago to Pittsburgh has been dealing with the most hazardous air conditions as the work week comes to a close. Thick smoke generated from wildfires burning in Ontario, Canada, is the culprit behind the unhealthy air.

There are over 800 wildfires raging across Canada, sending the smoke billowing to the south and into the U.S. The scene across many American cities is reminiscent of the historic outbreak of Canadian wildfires from three summers ago.

Air quality alerts are now in place for all of Wisconsin, Delaware, Pennsylvania, Michigan, New Jersey, Ohio, and Maryland. A number of America's largest cities have been caught up in the smoke, impacting millions of people. For instance, Chicago woke up to some of the worst air quality index (AQI) readings in the world, coming in with a measurement of 342.