Observation and analysis of atmospheric radon in Qingdao, China.

To investigate the levels and behaviours of the atmospheric radon concentration in Qingdao, a continuous measurement was carried out and recorded hourly over a three-year period from September 2006 to August 2009. Levels and variations were studied on the basis of 16,817 data points, and the trends of diurnal and seasonal variations were also analysed. The average concentration of atmospheric radon over the three years was 5.00 ± 3.01 Bq m(-3). The average diurnal pattern of radon concentration showed that the daily maximum appears in the early morning, and the daily minimum in the late afternoon, which is driven by the atmospheric stability. The annual pattern features a maximum around December and a minimum around June, which correlates with the origin of air mass brought by the monsoon.