Technics for prevention and mitigation of radon inflow in buildings

Abstract

Radon (Rn) is a radioactive gas that has no color, smell or taste and that can be found in soil as a result of the radioactive decay of naturally present elements such as uranium and radium. Radon can be present as well in building materials and water, but concentrations derived from them are usually lower than those derived from radon from soil. Radon is the greatest natural source of ionizing radiation and exposure of population to high levels of concentration of Rn during prolonged periods can become a public health problem. According to the World Health Organization (WHO), radon exposure is, in many countries, the second cause of lung cancer (after tobacco) for smokers and the first cause for nonsmokers, also having a predominant incidence in cases of childhood leukemia. For this reason, WHO recommends an annual average indoor radon level of 100 Bq/m3. Radon may enter buildings by convection through cracks in the envelope or by diffusion through the envelope itself when it is porous; and attain concentrations over the recommended reference levels, which values may vary according to the legislation of each country. The reference value of 300 Bq/m3 was established in The Council Directive 2013/59/EURATOM of 5 December 2013 laying down basic safety standards for protection against the dangers arising from exposure to incising radiation. This level is usually established as the legal indoor Rn maximum annual average for residential buildings and workplaces in most EU countries. The most usual methods to prevent or mitigate radon inflow in buildings include protection barriers, ventilation and sub-slab depressurization. However, the effectiveness of these methods is variable so they may need to be combined to increase overall efficiency in cases with high risk of radon concentration. In this communication, the factors that influence radon level and most usual methods to prevent or mitigate radon are presented and discussed as part of the training programme being developed to provide technical qualification for radon mitigation professionals, within the scope of the LeaRn4LIFE project. A reference to products and materials used for radon protection is also referred. Finally, recommendations are presented to guarantee the success of radon protection measures.