The air quality on Martha’s Vineyard may be unhealthy for people with sensitive lungs Wednesday, according to an alert put out by the state Department of Environmental Protection.

The DEP detected elevated levels of ozone in Dukes County, along with, Barnstable, Nantucket southern Plymouth and southern Bristol counties. The department recommended people with lung diesase, heart disease or asthma limit their outdoor exertion and take more frequent breaks.

The alert remains in effect until 11 p.m. Wednesday night.