The Pennsylvania Department of Environmental Protection has declared a Code Orange Air Quality Action Day due to ozone for May 25th for Montgomery County and other counties in the Philadelphia region.

The declaration is based on a forecast of “mostly sunny skies and temperatures in the middle 80s.” These conditions are expected to contribute to “robust ozone development and formation into the code ORANGE range during the afternoon hours.”

The U.S. Environmental Protection Agency’s (EPA) 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 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.