Outdoor radon concentration in China

A nationwide survey was conducted in 2014 to investigate environmental outdoor radon level in 33 provincial cities across China. The radon detector used was a passive-type solid-state nuclear track detector, CR-39. Measurements were conducted under the same condition following the quality control programme. Outdoor radon concentrations in China ranged from 3 to 30.0 Bq·m−3. The annual arithmetic and geometric mean radon concentration were 14 and 13.2 Bq·m−3, respectively. The radon concentrations in the locations near or along coastline were lower than the average value, while those located in the inland area were higher. As a whole, the result showed no big difference from the data measured during the period 1983–1998. It demonstrated that the outdoor radon concentration level in China has not been changing remarkably for 20 years