(WAND) – The Illinois Environmental Protection Agency has issued an Air Pollution Action Day for Friday.

An Illinois Air Pollution Action Day is issued when widespread ozone or particulate levels are expected to be at or above unhealthy levels.

Those with respiratory issues, along with small children and older individuals, should limit their time outdoors.

The haze to the sky is caused by smoke that is traveling from the wildfires in Canada, near Manitoba.

Even with the cooler weather, be sure to keep windows and doors closed until further notice.