The Pennsylvania Department of Environmental Protection is warning people of potentially dangerous levels of air pollution today.

Tuesday has been listed as code orange air quality action day alert day for ozone in Butler, Allegheny, Westmoreland, Beaver, Armstrong, and Fayette counties.

“A strong ridge of high pressure with light winds, sunshine, and unseasonably warm air in the middle to upper 80s will bring ozone concentrations to the code orange level,” according to DEP’s alert.

Young children, the elderly and people with repository issues such as asthma, emphysema and bronchitis are especially vulnerable to air pollution and should limit outdoor activities, the alert said.

To minimize air pollution, residents are encouraged to restrict pollution-producing activities by refueling cars and trucks after dusk, setting air conditioner thermostats to a higher temperature, carpooling or using public transportation and combining errands to reduce trips.

With a cold front anticipated Wednesday, conditions are expected to improve by Thursday, DEP said.