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.

Smoke from Canadian wildfires has returned to Central Illinois bringing significant reductions in air quality to Central Illinois. Air Quality Alerts have been issued for much of the state through Friday.

West-central Illinois is under a "moderate" air quality rating as smoke from Canadian wildfires drifts down into the Midwest.