The poor air quality continues to prevail in Illinois as Canadian wildfire smoke migrates south into the U.S. As a result, the Illinois Environmental Protection Agency has issued an Air Pollution Action Day for Friday, Aug. 1. Here's what we know.

The hazy skies in the Chicago area are the visible sign of the poor air quality Thursday as smoke from Canadian wildfires drifts into our area.

Chicago's air quality is considered among the worst in the world right now, thanks to thick wildfire smoke drifting southward from Canada. The smoke is prompting health concerns, triggering air quality alerts and smothering outdoor events in a dangerous haze.