Analysis of the spatial variation of indoor radon concentrations (national survey in Bulgaria)

  • Kremena IvanovaEmail author
  • Zdenka Stojanovska
  • Bistra Kunovska
  • Nina Chobanova
  • Viktor Badulin
  • Aleksey Benderev
Research Article


This paper presents the methodology and results of the national radon survey in Bulgaria and its spatial variability. The measurements were carried out in 2778 dwellings using CR-39 track detectors over two successive 9 and 3-month periods from April 2015 to March 2016. The arithmetic (AM) and geometric (GM) means of annual indoor radon concentration were 111 ± 105 Bq/m3 and 81 Bq/m3 (GSD = 2.15), respectively. The distribution of data has been accepted to be log-normal. Two hypotheses have been investigated in the paper. The first one was a spatial variation of indoor radon concentration and the second was spatiality of the factor that influences radon variation. The indoor radon concentrations in the 28 districts have been significantly different, which prove the first hypothesis. The influence of the factors, geology (geotectonic unit, type of rock, and faults distance of the measuring site), type of the region, and the presence of the basement in the building on radon spatial variation, was examined. The analyses have been shown that they significantly affect radon variations but with a relatively small contribution in comparison to the radon variation between district. Furthermore, the significance and contribution of the investigated factors were different in each district, which confirmed the second hypothesis for their spatiality.


National survey Indoor radon Geology Spatial variability Bulgaria 



The national survey has been conducted under the National Radon Program, funded by the Bulgarian Ministry of Health. The authors express their gratitude to the 28 Regional Health Inspectorates in the country, for the well-organized distribution of detectors and to all households who participated in the survey. A special acknowledgement to Peter Bossew from the German Federal Office for Radiation Protection, Berlin, Germany, for his careful manuscript reading and helpful comments.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Kremena Ivanova
    • 1
    Email author
  • Zdenka Stojanovska
    • 2
  • Bistra Kunovska
    • 1
  • Nina Chobanova
    • 1
  • Viktor Badulin
    • 3
  • Aleksey Benderev
    • 4
  1. 1.National Centre of Radiobiology and Radiation ProtectionSofiaBulgaria
  2. 2.Faculty of Medical SciencesGoce Delcev University of StipStipRepublic of Macedonia
  3. 3.Bulgarian Nuclear Regulatory AgencySofiaBulgaria
  4. 4.Geological InstituteBulgarian Academy of SciencesSofiaBulgaria

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