The Illinois Environmental Protection Agency has issued an Air Pollution Action Day for Wednesday August 6th for the greater Chicago Metropolitan Area through Midnight Wednesday night. A Chicago area 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 (AQI) for multiple days. Ozone is expected to be the primary pollutant of concern, but wildfire smoke also is lingering in the region and may impact PM2.5 and Ozone AQI Active children and adults, especially people with pulmonary or respiratory disease such as asthma, should limit prolonged outdoor activity. Area residents are urged to reduce pollution levels. Air quality forecasts, current air quality, and tips on how you can reduce your emissions can be found at www.airnow.gov. Media contact. Illinois EPA.