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.

Air quality alerts issued Thursday in Illinois because of Canadian wildfire smoke marked the latest bout in an increasingly common summer occurrence. The alert covers 34 Illinois counties designated as having unhealthy air for all residents.

A number of states in the United States have declared air quality warnings with concerning levels noted across many of the Great Lakes states including Wisconsin, Michigan, and Minnesota.