A Comparative Study of Indoor Radon Concentrations between Dwellings and Workplaces in the Ko Samui District, Surat Thani Province, Southern Thailand

Authors: Kanokkan Titipornpun, Tripob Bhongsuwan, Jan Gimsa

Abstract:

The Ko Samui district of Surat Thani province is located in the high amounts of equivalent uranium in the ground surface that is the source of radon. Our research in the Ko Samui district aimed at comparing the indoor radon concentrations between dwellings and workplaces. Measurements of indoor radon concentrations were carried out in 46 dwellings and 127 workplaces, using CR-39 alpha-track detectors in closed-cup. A total of 173 detectors were distributed in 7 sub-districts. The detectors were placed in bedrooms of dwellings and workrooms of workplaces. All detectors were exposed to airborne radon for 90 days. After exposure, the alpha tracks were made visible by chemical etching before they were manually counted under an optical microscope. The track densities were assumed to be correlated with the radon concentration levels. We found that the radon concentrations could be well described by a log-normal distribution. Most concentrations (37%) were found in the range between 16 and 30 Bq.m^-3. The radon concentrations in dwellings and workplaces varied from a minimum of 11 Bq.m^-3 to a maximum of 305 Bq.m^-3. The minimum (11 Bq.m^-3) and maximum (305 Bq.m^-3) values of indoor radon concentrations were found in a workplace and a dwelling, respectively. Only for four samples (3%), the indoor radon concentrations were found to be higher than the reference level recommended by the WHO (100 Bq.m^-3). The overall geometric mean in the surveyed area was 32.6±1.65 Bq.m^-3, which was lower than the worldwide average (39 Bq.m^-3). The statistic comparison of the geometric mean indoor radon concentrations between dwellings and workplaces showed that the geometric mean in dwellings (46.0±1.55 Bq.m^-3) was significantly higher than in workplaces (28.8±1.58 Bq.m^-3) at the 0.05 level. Moreover, our study found that the majority of the bedrooms in dwellings had a closed atmosphere, resulting in poorer ventilation than in most of the workplaces that had access to air flow through open doors and windows at daytime. We consider this to be the main reason for the higher geometric mean indoor radon concentration in dwellings compared to workplaces.

Keywords: CR-39 detector, indoor radon, radon in dwelling, radon in workplace.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1132755

References:

[1] WHO (World Health Organization), “WHO handbook on indoor radon: A public health perspective,” WHO press, Geneva, 2009.
[2] U.S. EPA, “A citizen’s guide to radon: the guide to protecting yourself and your family from radon,” Air and radiation, EPA 402-K-12-002, 2012.
[3] UNCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation), “Sources and effects of ionizing radiation,” United Nations, New York, vol. 1, 2000.
[4] NAS (National Academy of Science), “Health risks of radon and other internationally deposited alpha-emitters,” BEIR IV Report, National Academy Press, Washington, D.C., 1988.
[5] IARC (International Agency for Research on Cancer), “Man-made mineral fibres and radon,” IARC Monographs on the evaluation of carcinogenic risks to humans, ISBN 92-832-1243-6, 1988.
[6] ICRP (International Commission on Radiological Protection), “Lung cancer risk from exposures to radon daughters,” ICRP Publication, vol. 50, Ann. ICRP 17(1), 1987.
[7] NCRP (National Council on Radiation Protection and Measurements), “Exposure from the uranium series with emphasis on radon and its daughters,” Report 77, Bethesda, Maryland, 1984.
[8] U.S. EPA, “A physician's guide: The health threat with a simple solution,” Air and radiation, EPA 402-K-93-008, 1993.
[9] C. Edling, G. Wingreen and O. Axelson, “Quantification of the lung cancer risk from radon daughter exposure in dwellings-an epidemiological approach,” Environ. Int., vol. 12, issues. 1-4, pp. 55-60, 1986.
[10] U.S. EPA, “EPA assessment of risks from radon in homes,” Air and radiation, EPA 402-R-03-003, 2003.
[11] U.S. EPA, “Technical support document for the 1992 citizen's guide to radon,” Air and radiation, EPA 400-R-92-011, 1992.
[12] UNCEAR, Effects of ionizing radiation- ANNEX E- Sources-to-effect assessment for radon in homes and workplaces. New York: United Nations, vol. 2, 2006.
[13] M. Faheem and Matiullah, “Radon exhalation and its dependence on moisture content from samples of soil and building materials,” Radiat. Meas., vol. 43, pp. 1458-1462, 2008.
[14] J. Kemski, R. Klingel, A. Siehl and M. Valdivia-Manchego, “From radon hazard to risk prediction-based on geological maps, soil gas and indoor measurements in Germany,” Environ. Geol., vol. 59, pp. 1269-1279, 2009.
[15] A. Kumar and Chauhan, “Measurement of indoor radon-thoron concentration and radon soil gas in some North Indian dwellings,” J. Geochem. Explor., vol. 143, pp. 155-162, 2014.
[16] H. M. Al-Khteeb, K. M. Aljarrah, F. Y. Alzoubi, M. K. Alqadi and A. A. Ahmad, “The correlation between indoor and in soil radon concentrations in a desert climate,” Radiat. Phys. Chem., vol. 130, pp. 142-147, 2017.
[17] Prabhjot Singh, Parminder Singh, S. Singh, B. K. Sahoo, B. K. Sapra and B. S. Bajwa, “A study of indoor radon, thoron and their progeny measurement in Tosham region Haryana, India,” J. Radiat. Res. and Appl. Sci., vol. 8, pp. 226-233, 2015.
[18] S. Rahman, Matiullah and B. M. Ghauri, “Comparison of seasonal and yearly average indoor radon levels using CR-39 detectors,” Radiat. Meas., vol. 45, pp. 247-252, 2010.
[19] O. Burke and P. Murphy, “Regional variation of seasonal correction factors for indoor radon levels,” Radiat. Meas., vol. 46, pp. 1168-1172, 2011.
[20] A. Cucos (Dinu), C. Cosma, T. Dicu, R. Begy, M. Moldovan, B. Papp, D. Nita, B. Burghele and C. Sainz, “Thorough investigations on indoor radon in Baita radon-prone area (Romania),” Sci. Tot. Environ., vol. 431, pp. 78-83, 2012.
[21] H. M. Al-Khateeb, A. A. Al-Qudah, F. Y. Alzoubi, M. K. Alqadi and K. M. Aljarrah, “Radon concentration and radon effective dose rate in dwellings of some villages in the district of Ajloun, Jordan,” Appl. Radiat. Isot., vol. 70, pp. 1579-1582, 2012.
[22] K. Titipornpun, J. Gimsa, T. Bhongsuwan, N. Kongchouy, and A. Titipornpun, “Radon concentration measurements in secondary schools, Surat Thani province, Thailand,” Conference of the International Journal of Arts & Sciences, vol. 8, no. 1, pp. 31-40, 2015.
[23] K. Titipornpun, A. Titipornpun, P. Sola and T. Bhongsuwan, “Measurements of indoor radon concentrations in Chaiya and Tha Chana districts, Surat Thani province, Thailand,” J. phys. Conf. ser., vol. 611, doi. 10.1088/1742-6596/611/1/012027, 2015.
[24]
[24] K. Titipornpun, S. Sriarpanon, A. Titipornpun, J. Gimsa, T. Bhongsuwan and N. Kongchouy, “Measurements of indoor radon concentrations in the Phanom and Ko Pha-ngan districts of Surat Thani province, Thailand,” Chiang Mai J. Sci., vol. 43, no. 3, pp. 494-502, 2016.
[25] M. Manousakas, A. Fouskas, H. Papaefthymiou, V. Koukouliou, G. Siavalas and P. Kritidis, “Indoor radon measurements in a Greek city located in the vicinity of lignite-fired power plants,” Radiat. Meas., vol. 45, pp. 1060-1067, 2010.
[26] L. M. O. Martins, M. E. P. Gomes, R. J. S. Teixeira, A. J. S. C. Pereira and L. J. P. F. Neves, “Indoor radon risk associated to post-tectonic biotite granites from Vila Pouca de Aguiar pluton, northern Portugal,” Ecotoxicol. Environ. Saf., vol. 133, pp. 164-175, 2016.
[27] B. Collignan, E. L. Ponner and C. Mandin, “Relationships between indoor radon concentrations, thermal retrofit and dwelling characteristics,” J. Environ. Radioact., vol. 165, pp. 124-130.
[28] K. Wattananikorn, S. Emharruthai and P. Wanaphongse, “A feasibility study of geogenic indoor radon mapping from airborne radiometric survey in northern Thailand,” Radiat. Meas., vol. 43, pp. 85-90, 2008.
[29] J. S. Duval, “Indoor radon prediction using gamma-ray spectrometric data,” EOS, Trans. Amer. Geophys. Union, vol. 70, pp. 496-502, 1988.
[30] F. Abu-Jarad, J. H. Fremlin and R. A. Bull, “A study of radon emitted from building materials using plastic α-track detectors,” Phys. Med. Biol., vol. 25, pp. 683-694, 1982.
[31] H. A. Abel-Ghany, “Exposure of school children to alpha particles,” Iran. J. Radiat. Res., vol. 6, no. 3, pp. 113-120, 2008.