Indoor radon measurements in areas of northern Greece with relatively high indoor radon concentrations

Abstract

Indoor radon concentrations were measured in 77 schools of the prefecture of Xanthi in northern Greece. The arithmetic mean radon concentration is 231 Bq m(-3) with a range between 45 and 958 Bq m(-3). Thirty five schools have mean radon concentration above 200 Bq m(-3) and nine schools have mean radon concentration above 400 Bq m(-3). From continuous radon gas measurements in the school with a relative higher radon concentration (958 Bq m(-3)) was deduced the 'true' radon concentration, defined as the radon concentration in the school during the hours of the presence of teachers and scholars. The mean 'true' radon concentration for a time period of about 2 weeks was 104 Bq m(-3). The mean radon concentration for the same 2 weeks was seven times higher (700 Bq m(-3)). Greek and International regulations for radon in workplaces refer to only the mean annual radon concentration. It would be preferable for schools to replace the mean annual radon concentration with the 'true' radon concentration.

Indoor radon levels in Greek schools

“…In the present work, a factor of 4 was measured between mean and "true" radon concentration in one school with a relatively low radon concentration. Previously, Clouvas et al (2009) reported a factor of 7. As expected, no correlation between radon gas concentration and indoor gamma dose rate was observed.…”

“…Indeed there is an overestimation, but it is not a little overestimation, it is a very important overestimation. As an example, in the school with the higher annual radon concentration (958 Bq m À3 ), we (Clouvas et al, 2009) performed from 20 January 2009 up to 4 February 2009 radon measurements every 10 min. The AM radon concentrations when the school was in operation and when it was closed were 104 Bq m À3 and 866 Bq m À3 respectively.…”

“…In Greece, two relatively large radon surveys have been carried out from 1995e1998 in 1277 dwellings (Nikolopoulos et al, 2002) and from 1999e2006 in 561 workplaces (Clouvas et al, 2007) respectively. Smaller surveys concerning radon measurements only in schools were performed by Papaefthymiou and Georgiou (2007) in the town of Patras, Geranios et al (2001) in the town of Kalamata and Clouvas et al (2009) in the area of Xanthi.…”

Radon and radioactivity at a town overlying Uranium ores in northern Greece

“…Among the 19 studied Prefectures, the Prefecture of Xanthi had the highest mean radon concentration (229 Bq m À3 ) and the highest percentage (42%) of schools with 222 Rn concentrations above 200 Bq m À3 . In a follow-up study, Clouvas et al (2009) measured indoor radon concentrations in 77 schools of the prefecture of Xanthi in winter. The arithmetic mean radon concentration was 231 Bq m À3 with a range between 45 and 958 Bq m À3 .…”

Results of radon CR-39 detectors exposed in schools due two different long-term periods

“…The differences are more pronounced between short-term measurement by active method and passive long--term method. For example, using short-term measurements with active method, Clouvas et al, 2009 found that: (a) in school with a high level of radon during school time, the concentrations were lower by a factor of 7 than when the school was closed; (b) in school with low levels, this difference was a factor of 4 [6]. Similar radon dynamic has been reported for Slovenian schools [7,8].…”