AUGUSTA — The Maine Department of Environmental Protection has issued an air quality alert because of climbing levels of ground-level ozone concentrations.

The agency says there will be “unhealthy” levels along the coast from Kittery to Georgetown on Thursday. Moderate levels are also possible in the Midcoast region, the Downeast coast and the western interior of the state.

The DEP says elevated ozone levels can cause some people to experience reduced lung function and irritation. Symptoms can include shortness of breath, coughing and an uncomfortable sensation in the chest.

People at risk include children, adults who suffer from respiratory diseases, and healthy adults who exert themselves.