National Weather Service officials issued an air quality alert set to expire at midnight Saturday for the Chicago and surrounding areas. The Illinois Environmental Protection Agency determined an

An Illinois Air Pollution Action Day is declared when weather conditions are such that widespread ozone and or particulate levels are expected to be at or above the Unhealthy for Sensitive Groups (USG) category of the Air Quality Index for all or almost all of Illinois.

An air quality alert for the Chicago area was extended for a second time as smoke from Canadian wildfires lingers overhead Saturday. The National Weather Service extended an air quality alert for Chicago through Sunday night,