In this paper the results of a four-year monitoring campaign carried out in a semi-rural site near Urbino, Central Italy, for ozone and for radon gas are reported and discussed. Radon can be considered as an index of vertical diffusion in the boundary layer. Its trend evidences the presence of temperature inversion such as the formation of the nocturnal stable layer and gives information on the vertical turbulence and the motion of air masses. Therefore, a simple measurement of radon concentration at ground resulted to describe the temporal evolution of the pollutants in the atmosphere. A comparison between the daily concentrations trend of ozone with that of radon gas was performed. The evolution of the convective boundary layer during daytime and the stable nocturnal boundary layer (NBL) were found to have marked impacts on ozone concentrations.