1. Perko Vukotic, Montenegrin Academy of Sciences and Arts, R. Stijovica 5, 81000 Podgorica, Montenegro, Montenegro
2. Ranko Zekic, Centre for Ecotoxicological Research, Bulevar S. De Gola 2, 81000 Podgorica, Montenegro, Montenegro
3. Tomislav Andjelic, Centre for Ecotoxicological Research, Bulevar S. De Gola 2, 81000 Podgorica, Montenegro, Montenegro
4. Nikola Svrkota, Centre for Ecotoxicological Research, Bulevar S. De Gola 2, 81000 Podgorica, Montenegro, Montenegro
5. Aleksandar Dlabac, Centre for Nuclear Competence, University of Montenegro, Dz. Vasingtona bb, 81000 Podgorica, Montene, Montenegro
In the framework of the national project MNE9005, funded by the International Atomic Energy Agency and the Government of Montenegro, radon survey was performed during the academic year 2016/17 (September − June) in all 519 buildings of the pre-university education in Montenegro - 376 buildings of primary and 51 of high schools, 81 kindergarten buildings, 4 buildings of resource centers and 7 of student dormitories. Radosys detectors (RSFV type) were placed in all classrooms, playrooms and offices on the ground floor, as well as in some rooms on the first floor. Number of deployed detectors was 4078, of which 3793 were basic and 285 control detectors (paired with basic detectors approximately at every 12th location). After exposure period, 11.4% of the detectors were lost or damaged.
Average 9-month radon activity concentrations were obtained for 3345 sampled rooms in 507 buildings. Their mean values AM = 243 Bq/m3 and GM = 142 Bq/m3 are more than twice higher than the corresponding annual average values for 953 dwellings in Montenegro − AM = 110 Bq/m3 and GM = 58.3 Bq/m3, obtained in the national indoor radon survey. Average radon concentrations above of 300 Bq/m3 are found in 23.3% of all sampled rooms in educational institutions and in 3.4% of all rooms they were above 1000 Bq/m3, whereas in the Montenegrin homes these percentages are 7.9% and 0.6%, respectively, which means 3 to 5 times lower.
Radon was measured in 2855 ground-floor rooms in 468 educational buildings. The obtained average 9-month radon concentrations are in range from 3 Bq/m3 to more than 3600 Bq/m3, while mean values for all these rooms are AM = 261 Bq/m3 and GM = 152 Bq/m3. Radon concentrations in the educational buildings, averaged over all sampled ground-floor rooms of the building, range from 16 Bq/m3 to 2810 Bq/m3, with AM = 275 Bq/m3. There are 135 (or 28.8%) buildings with average indoor radon concentrations on ground floor above 300 Bq/m3, and 18 (or 3.8%) buildings where they are above 1000 Bq/m3.
It can be concluded that, on average, radon concentrations in educational institutions are significantly higher than in Montenegrin homes, and that each fourth building of pre-university education in Montenegro has an issue with radon exposure of children and educators in it. This is probably due to the type of construction of educational institutions (usually spacious low-rise structures) and a relatively high average age of these buildings.