The Department of Environmental Protection is forecasting a code Orange air quality action day for ozone for Saturday in the Susquehanna Valley region, which includes York County.

On air quality action days, 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.

The temperature is expected to approach 100 degrees on Saturday in the York area. With the humidity factored in, it will seem more like 105 degrees, the weather service has said.

The U.S. Environmental Protection Agency's standardized air quality index uses colors to report daily air quality. Green signifies good; yellow means moderate; orange represents unhealthy pollution levels for sensitive people; and red warns of unhealthy pollution levels for all.