Concern for poor air quality in the greater Chicago area remains as the Illinois EPA extends its alert until Thursday night. The city also is expected to get slightly warmer each day until the weekend.

According to the National Weather Service, the air quality alert remains in effect through midnight in parts of the Chicago area, including Kane, DuPage, Kendall, Grundy, Cook and Will counties.

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.