HARRISBURG, Pa., (WHTM) — The Pennsylvania Department of Environmental Protection (DEP) has declared a Code Orange Air Quality Action Day for fine particulate matter for Thursday, Nov. 24.

This includes Cumberland, Dauphin, Lancaster, Lebanon, and York.

The DEP has said that a strong overnight and morning temperature inversion and light winds will likely contribute to daily average concentrations of fine particulate matter in the Code Orange range on Thursday.

The United States Environmental Protection Agency Air Quality Index provided color codes for forecasting and reporting air quality:

  • Green: No health impacts are expected
  • Yellow: Extremely sensitive people may wish to limit outdoor exertion
  • Orange: Unhealthy pollution levels for sensitive groups of people.
  • Red: Everyone should limit exertion outdoors

An Air Quality Action Day is declared when the AQI is forecasted to be Code Orange or higher. On an Air Quality Action Day, young children, the elderly, and those with respiratory problems, such as asthma, emphysema, and bronchitis, are especially vulnerable to the effects of air pollution and should limit outdoor activities.