(WHTM) — A “Code Orange Air Quality Action Day” was declared by the Pennsylvania Department of Environmental Protection in the Midstate and other parts of the Commonwealth for Friday, May 12, due to ozone.

The DEP says the Susquehanna Valley area (Cumberland, Dauphin, Lancaster, Lebanon, and York Counties), the Philadelphia area (Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties), and the Lehigh Valley-Berks area (Berks, Lehigh, and Northampton Counties) will be impacted.

Sunny weather, alongside warm temperatures and light winds, will contribute to the eight-hour concentration of ozone, which prompted the Code Orange for Friday.

The Air Quality Index has four different levels: green for good quality, yellow for moderate quality, orange for unhealthy pollution levels for certain people, and red for unhealthy pollution for everyone.

Air Quality Action Days, as described by the United States Environmental Protection Agency, are when the Air Quality Index is orange or higher.

The DEP encourages residents to help reduce ozone air pollution by driving less/carpooling, combining errands to limit car trips, limiting idling your engine, getting gas after dusk, and conserving electricity.