The Pennsylvania Department of Environmental Protection has declared a Code Orange Air Quality Action Day due to ozone for Wednesday, July 20th for Montgomery County and other areas of the state.

The declaration is based on a forecast for “mostly sunny skies, light southwest winds, and high temperatures in the low to mid 90s.” These conditions are expected to contribute to an 8-hour average concentration of ozone in the Code Orange range on Wednesday.

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.