Seyed Ali Rahimi

Mazandaran University of Medical Sciences, Kilmer 18 KHAZARABAD Road, P.O. BOX: 48175-1553, SARI, IRAN

Abstract:

Background and Purpose: Indoor air samples taken in buildings throughout the SARI city provinces of Mazandaran, Iran, were analyzed for airborne radon concentrations using charcoal canisters. Measurements were made during the years 2009-2010. These were: soil type, construction materials used, the height of the room above ground level, and the degree of ventilation.

Materials and Methods: The geometrical mean indoor concentration was 21.85 Bq m(-3). An estimated annual effective dose of 0.057 μSv y (-1) was calculated for residents, assuming an equilibrium factor of 0.4 and an occupancy factor of 0.8. The relative importance of the principal variables that condition radon concentrations inside buildings was also delimited experimentally.

Results: The sampling period should be chosen not longer than 2 hours. Otherwise the loss of Radon by diffusion through the tube walls etc. becomes significant (even if the air loop is pressure tight). The table below shows a comparison of various sampling configurations with respect to the expected detection limits: Air-Volume Sensitivity of the Radon monitor Sampling Interval Detection Limit (2-Sigma) ml ml cpm/(kBq/m³) min Bq/l 500 130 3 5 0.096-500 380 3 30 0.033- 500 1200 5 5 0.315-100 1200 5 30 0.244.

Conclusion: The resulting "Radon in Air Concentration" is equal to the detection limit of the Air measurement. More detailed information about the detection limit, statistical error and test planning you will find in the application note AN-002 ("Measuring principals - decay statistics - test planning").

Keywords: Indoor radon, exposure, etching and inhalation dose.