Ozone ad related meteorological data are reported (1987-1992) for the Rock Springs rural site in the Nittany Valley, PA. The mean ozone concentrations is 33.1 ppb in the period of 1987-1992. During summer ozone exhibits a systematic diurnal pattern. This pattern has been supported by the NOx-O-3, process. Enhanced daytime ozone formation explained by favorable photochemical conditions. In winter ozone levels remain constant. A small fluctuation has been found.