Levels and distribution of indoor radon concentrations in Shenzhen, China

Abstract

Objective To investigate the levels and distribution of radon in dwellings in Shenzhen cities of China. Methods A total of 108 low-, multi-, middle- and high-rise buildings were selected. Indoor radon concentrations were measured by using solid track detector. Results The arithmetic mean of indoor radon concentrations in Shenzhen was 64 Bq/m3, and geometric mean was 58 Bq/m3, in range of 15 to 155 Bq/m3. The average indoor radon concentration in Bao'an district was 50 Bq/m3 with the lowest value, and that in Pingshan new district was 87 Bq/m3 with the highest value. There were 12 measuring points where indoor radon concentrations were higher than 100 Bq/m3 in Shenzhen, accounting for 11.1% of the total number. Shapiro-Wilk test showed that the frequency distribution of indoor radon concentration in Shenzhen follows lognormal distribution (P>0.05). The indoor radon concentrations showed a downward trend from 1990 to 2015. The indoor radon concentration decreases with the elevated floors except 10th and above floors. Conclusions The indoor radon concentrations in Shenzhen increased by 35%, compared to the previous investigations. It is recommended that efforts continue to improve radioactive materials standards about building material and to enhance the natural ventilation in high-rise buildings in order to lower the radiation hazards from radon. Key words: Shenzhen; Indoor air; Radon concentration; Building material