The Pennsylvania Department of Environmental Protection on Tuesday issued a Code Orange Air Quality Action Day for ozone in Butler County.

According to the alert, a combination of a mostly sunny sky and high temperatures in the mid-90s will likely contribute to eight-hour average concentrations of ozone in the Code Orange range on Wednesday.

The U.S. Environmental Protection Agency’s Air Quality Index (AQI) provides standardized color codes for forecasting and reporting daily air quality. Green signifies good air quality, yellow means moderate air quality, orange represents unhealthy pollution levels for sensitive groups of people and red warns of unhealthy pollution levels for all.

An Air Quality Action Day is issued 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.

Residents and businesses within the Air Quality Action Day areas are strongly encouraged to voluntarily help reduce air pollution by:

- Driving less by carpooling or using public transportation

- Combining errands to reduce vehicle trips

- Limiting engine idling

- Refueling cars and trucks after dusk

- Conserving electricity by setting air conditioning to a higher temperature and turning off lights that are not in use.

Other affected counties in Southwestern Pennsylvania include Allegheny, Armstrong, Beaver, Fayette, Washington and Westmoreland counties.