Modelling of indoor Radon activity concentration dynamics and its validation through in-situ measurements on regional scale

A model has been developed for the calculation of the Radon activity concentration in indoor air, taking into account all the different important parameters responsible of the global Radon dynamics, from its generation into the source (soil, water or building material) to its accumulation in confined spaces. The Radon accumulation into buildings is mainly due to the transport from the soil dominated by diffusion, pressure driven flow or a mixture of both depending on the real conditions. Experimental observations and measurements were caned out on different sites in the Campania Region (Italy) to gain valuable information about the various parameters influencing the indoor Radon level. The acquired results indicate that, generally, in the regional area, indoor Radon accumulation is not only due to the transport from the ground to the building, driven by pressure differences, through the basement, but it is also due to the direct exhalation from building materials. So, aim of this work was to refine a physical mathematical model of the Radon dynamics, developed in a previous work by the authors, by gathering and incorporating realistic experimental values. A graphical plot has been elaborated for an easy visualization and interpretation of the data.