The Indiana Department of Environmental Management issued an ozone advisory for Lake, LaPorte and Porter counties because of ozone levels that are forecast to be high.

IDEM says elderly residents, children and anyone with heart or lung conditions should reduce their physical exertion in the affected counties.

Ground-level ozone can cause coughing and breathing difficulties. It’s formed when sunlight and hot weather bake vehicle exhaust, factory emissions and gasoline vapors.

IDEM urges people to help reduce ozone by conserving energy, reducing their use of individual motor vehicles, and avoiding refueling vehicles or using gasoline-powered lawn equipment until after 7 p.m.