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Abstract. In the time of energy saving it is important to save heating costs. Different methods of thermo insulation are developed and one of them, besides the comprehensive use of thermo insulation materials, is the use of masonry consisting of aerated concrete blocks. In order to determine the contribution of aerated concrete to the total scope of heat insulation it is important to determine the distribution of humidity in the wall construction. As the construction terms are short and usually all tests are done in the habitable buildings, it is difficult to use destructive methods for the determination of humidity level in the wall constructions. This is the reason why the importance and frequency of application of non destructive methods for detection of wall humidity are increasing. One of such methods for non destructive determination of humidity level in aerated concrete constructions is application of electrical impedance spectrometry. In laboratorial test series it is detected that along with the increasing of the humidity level in aerated concrete block the electrical impedance of the construction decreases. Using this method it is possible to detect the distribution of humidity throughout the construction in relative means. If absolute means are important, then calibration work must be performed prior to field testing. In order to increase the accuracy of the results obtained, the frequency analysis must be performed for every type of testing material. In this paper non destructive testing of aerated concrete blocks for determination of the distribution of humidity level as well as frequency analysis for aerated concrete blocks is described.

Among the physical pollutants affecting indoor air, the radioactive gas radon may turn out to be the most hazardous. Health effects related to radon exposure have been investigated for several decades, providing major scientific evidence to conclude that chronic exposures can cause lung cancer. Additionally, an association with other diseases, such as leukemia and cancers of the extra-thoracic airways, has been advanced. The implementation of a strategy to reduce the exposure of the population and minimize the health risk, according to the European Directive 59/2013/Euratom on ionizing radiations, is a new challenge in public health management. Starting from an understanding of the general state-of-the-art, a critical analysis of existing approaches has been conducted, identifying strengths and weaknesses. Then, a strategy for assessing the radon exposure of the general population, in a new comprehensive way, is proposed. It identifies three main areas of intervention and provides a list of hazard indicators and operative solutions to control human exposure. The strategy has been conceived to provide a supporting tool to authorities in the introduction of effective measures to assess population health risks due to radon exposure.

The accumulation of the radioactive gas radon in closed environments, such as dwellings, is the result of a quite complex set of processes related to the contribution of different sources. As it undergoes different physical mechanisms, all occurring at the same time, models describing the general dynamic turns out to be difficult to apply because of the dependence on many parameters not easy to measure or calculate. In this context, the authors developed, in a previous work, a simplified approach based on the combination of a physics-mathematical model and on-site experimental measurements. Three experimental studies were performed in order to preliminarily test the goodness of the model to simulate indoor radon concentrations in closed environments. In this paper, an application on a new experimental site was realized in order to evaluate the adaptability of the model to different house typologies and environmental contexts. Radon activity measurements were performed using a portable radon detector and results, showing again good performance of the model. Results are discussed and future efforts are outlined for the refining and implementation of the model into software.

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