Ozone Forecasting

Meteorologists at the Pennsylvania Department of Environmental Protection use up-to- date weather information and special forecast models to predict ozone levels for the following day. Ozone forms when hydrocarbons (VOCS) and nitrogen oxides (NO.) emitted by motor vehicles, industrial operations, paints and solvents and other household products react with sunlight Weather conditions that contribute to the formation of ground-level ozone include: high ultraviolet radiation index, temperature in the 80's or 90's, stagnant air, little cloud cover and lack of precipitation. Ground-level ozone concentrations begin to rise in the late morning hours, peak during the evening rush hour, then decrease again after sunset Thunderstorms, high winds and fresh air masses that move in during the day can reduce ground-level ozone. However, if there is very little movement of air masses and hot air remains, high ozone levels can continue over a large area for several days, creating an 'ozone episode." 

Ozone Action Day Notification System 

By 3:00 p.m. on the day before a predicted Ozone Action Day, the Ozone Action Partnership will fax an advisory to the local media and to all Ozone Action Partners in Berks, Lehigh and Northampton counties. The media are asked to inform the public by featuring Ozone Action as a part of their summer news and weather reports, and by reporting the health precautions and voluntary actions that should be taken on Ozone Action Days. Businesses and organizations that are Ozone Action Partners are asked to inform their employees about Ozone Action through channels such as e-mail or voice mad, or by posting Ozone Action notices at main entrances and exits.