German O. Scientific justification of radon remediation measures for buildings situated in the radon prone territories of Ukraine

This thesis paper justifies the optimal radon remediation methods of radon-222 activity reduction in the indoor air of the typical Ukrainian buildings and verifies the radon risk mapping tool. The analysis of the major influencing factors on radon activity indoors is based on the complex investigation of private rural homes as well as educational establishments for children in the selected pilot regions. The following parameters were included in the analysis: indoor radon concentration, construction and engineering characteristics of the buildings, radon and NORM concentrations in soil. The mathematic methods of analysis proved that radon indoor activity is strongly dependent on the building itself, i.e. number of floors and foundation construction, type of ventilation and surrounding ground conditions (type of ground and soil). Based on the gamma spectrometric, gamma rate, radon activity concentration measurements in ground and geo-morphological characteristics of the territory the radon prone area map was developed for the Savran' pilot district in Odessa Oblast, using the obtained measurements data. The radon prone area map identified radon areas with normal and low radon risk. These conclusions were verified by indoor radon measurements during the heating season. Radon remediation measures were adjusted and recommended for specific Ukrainian conditions. The recommended remediation was implemented in several educational establishments for children in Kirovograd Oblast. Using the radon health risk assessment for the children that spend their time in the affected nurseries of schools prioritization for remediation actions was performed and motivated. The recommended remedial actions were performed in the frame of a regional project and supported by the regional government. A second set of indoor radon measurements in Kirovograd region was carried out in the remediated buildings and the efficiency of the remedial actions was assessed based on the comparison of the annual radon activity and the radon health risks for children prior and after the remediation. The last chapter of the thesis work is focused on recommendations for successful implementation of the National Radon Action Plan for Ukraine. The two most important are: 1.The ground and soil characteristics as a measure of air availability for the indoor volume in combination with the construction characteristics of the buildings, must be considered for the choice of radon remedial measures. For this purpose, radon activity measurements in ground must be performed and analyzed combined with the analysis of construction parameters of each building in question at the stage of remediation planning. 2.One of the important learnings of the remedial project performed in Kirovograd region proved the urgent need of education and training of radon experts that are tasked to plan and perform the remedial work as well as experts involved into public radon risk communication. The results of the Ph.D thesis were used for development of the following documents: 1.Methodology for Radiation Hygiene Monitoring Programme (MP 6.6.1.6.2.-000.14) published by the Ministry of Health of Ukraine in 2014. 2.Education and training material for 5 series of lectures performed in Odessa and Kirovograd oblast: radon basics, radon measurements, natural radioactivity in water, radon mapping and radon remediation. 3.Education materials for Geological Faculty students at the National Taras Shevchenko University (2014-2016). 4.Instructions for the sanitary epidemiological supervision at SE "Rovno laboratory center of the Ministry of Health". 5. Radon risk communication publication "Radon. What one needs to know to protect oneself and family" published 2014.