The Maine Department of Environmental Protection has issued an air quality alert for Monday, warning people with breathing sensitivities that they may want to consider remaining inside or at least scaling back their outdoor activities.

The DEP, in an alert issued Sunday afternoon, said that ozone levels unhealthy for sensitive groups will affect the southwest coastal region of Maine from Kittery to Popham Beach in Phippsburg. The alert goes into effect Monday at 11 a.m. and will continue through 11 p.m.

The affected area encompasses all of coastal York, Cumberland and Sagadahoc counties. Towns such as Biddeford, Saco, Old Orchard Beach, Kittery, Portland, South Portland, Westbrook, Bath and Topsham could be impacted, according to an alert posted on the Maine DEP’s website.

The DEP recommends that people with respiratory or heart disease, the elderly, children and teenagers limit prolonged or heavy exertion on Monday. It will be safe to be outside, but those people should take more breaks and do less intense activities. Symptoms may include shortness of breath or coughing.

Hot and humid conditions and transporting winds are causing increased ozone levels in the southwest coastal region. Those conditions may continue into Tuesday and Wednesday.

Persons with concerns about air quality levels can stay informed by calling the DEP’s air quality hotline at 1-800-223-1196.