SPRINGFIELD, Ill. (WMBD) — The head of the Illinois Environmental Protection Agency said air quality conditions Friday are expected to be in the “Unhealthy for Sensitive Groups” category for all of Illinois on Friday.

IEPA Director John J. Kim said Ground-level ozone is formed when emissions of nitrogen oxides and volatile organic compounds from vehicles, power plants, and other industrial sources, react in the presence of sunlight.

Conditions pose a potential health hazard to people with respiratory or pulmonary disorders as well as active children and adults.

Sensitive individuals should take special precautions and follow their physician-prescribed regimen. All residents should keep cool and limit physical activity when air quality is low.

Possible symptoms related to sensitive groups impacted by low air quality include coughing or shortness of breath.

Because air quality can change from day to day, the IEPA provides daily air quality forecasts based on the Air Quality Index (AQI) for fourteen sectors throughout Illinois.

The AQI is a color-coded system that classifies air quality from Good (Green) to Hazardous (Maroon). Air quality forecasts are available at www.airnow.gov. Residents are also encouraged to subscribe to receive air quality forecasts via email or Twitter at http://illinois.enviroflash.info.

U.S. EPA has also published an Ozone Air Quality guide which can be found here.