Development of a Pre-Diagnosis Procedure for the Evaluation of Indoor Radon Potential in Buildings

Abstract

Indoor radon accumulation is considered the main source of human exposure to ionizing radiation. Depending on the average radon level, indoor long-term exposure can significantly increase the risk of lung cancer onset. The publication of international regulations on the protection of human health the exposure of ionizing radiation, defining threshold values over whom health consequences for occupants could be expected, led to the control and testing of radon levels in workplaces and premises using multiple techniques and approaches. In particular, since the main source of radon is soil, many efforts have been done for the redaction of maps of the geogenic potential risk, as well as the definition of proper measurement standards and techniques for indoor monitoring. Radon maps, based on geology and measurements of radon and/ or the natural radioactive content in the soil, constitute an evaluable tool for decision-making authorities in radon policies giving the possibility to characterize areas for radon risk where indoor radon measurements are not available. But, of course, they are not completely descriptive of the potential risk, so indoor monitoring in buildings is also required. The correct design of an indoor monitoring campaign is a crucial topic.. Scientific literature has largely demonstrated that many site-specific features influence the accumulation process, as well as most building materials represent a significant source, after the soil. The preliminary complete investigation in buildings should be properly defined since radiation safety in a situation of radon exposure completely ensured during the building's construction and maintenance phases as well as during the selling/rental ones. So, the aim of this work is to put the basis for the development of a pre-diagnosis procedure as a tool for the screening of buildings susceptible to high indoor radon activity concentrations. The work represents a very early stage of implementation of a qualitative method for the design of a measurement campaign for the indoor radon assessment. A pre-evaluation selection of the variables that play a leading role in the accumulation process is presented. A prior survey, based on evidence in scientific literature, was done to identify all relevant characteristics that most affect indoor radon levels, mainly concerning local geology, building features, ventilation, and occupancy factors. The selected parameters, classified into levels according to defined indicators and then combined, allow a more refined sample selection for measurements campaign in the indoor radon assessment process. Future development will be oriented to the validation of case studies and the implementation of the procedure in a software environment which will be the first tool available to systematize and regulate the radon monitoring process for short-term decision-making.