No abstract

The main purpose of this paper is to analyse the activities for Radon Risk Communication under the National Radon Program and to outline the main objectives in the new Radon Action Plan for developing a communication strategy. The preliminary activities were implemented under the National Radon Program. Survey via the Internet for assessment of perceptions and the level of knowledge regarding radon was conducted as a benchmark for evaluation of public awareness. The main channels which were used to inform the population were publications on websites, magazines, in TV interviews and radio (local), seminars, from which the most widely used were local seminars. On the basis of this, six objectives are proposed for a new radon action plan: to obtain wide organisational support and to determine the need of risk communication; to develop goals for risk communication with key messages to different target groups; to form and to train the communication team; to evaluate the stakeholders and the communication channels; to develop plans with different organisations for different focus groups; to evaluate the radon risk communication programme.

No abstract

As a part of the systematic survey of indoor radon in Bulgaria, the indoor radon concentration was measured in 296 kindergarten buildings of Sofia city during 3 months (February to April 2013) using the CR-39 nuclear tract detectors. In 256 buildings at least two frequently occupied rooms (mainly playrooms) were observed. Altogether, 922 measurements were performed. The frequency distribution was well described by the lognormal function. The measured radon concentrations range between 9 and 1415 Bq m(-3) with a geometric mean of 101 Bq m(-3) (2.08) and an arithmetic mean 132 Bq m(-3) with a standard deviation of 118 Bq m(-3). The radon concentrations obtained in this survey were compared with that in Sofia city dwellings obtained from a previous study. A detailed statistical analysis of the building factors was presented.

The first systematic indoor radon survey in four districts of Bulgaria was performed. Three hundred and seventy-three selected ground floor dwellings were measured using the nuclear track detectors during 6 months, from October 2011 to May 2012. It was found that indoor radon concentration varied between 20 and 3560 Bq m(-3) with median value of 90 Bq m(-3). The fractions of dwellings in four districts: Sofia city, Sofia districts, Plovdiv and Varna above the reference levels of 300 Bq m(-3) were 3, 9, 14 and 5 %, respectively. Each data set does not follow a log-normal distribution at a significance level of 95 %. The results of the analysis of the variance showed statistically significant differences among the indoor radon concentrations for the regions between urban and rural municipalities as well for the building with and without basement. These results may be utilised to set up the methodology for a more systematic survey in Bulgaria.