Characteristics of Indoor and Soil Gas Radon, and Discussion on High Radon Potential in Urumqi, Xinjiang, NW China

Urumqi City, located in the northwest of China, is a city with a high indoor radon concentration in a nationwide indoor radon survey in China. This study focuses on the assessment of the indoor radon level and its distribution in this city. Indoor radon measurement using RAD7 and solid nuclear track detector (SSNTD), soil gas radon measured by RAD7, and the determination of the specific activity of uranium and radium in soil samples by a high pure germanium spectrometer were performed from 2021 to 2023. The results reveal a wide range of indoor radon concentrations in Urumqi, with anomalies above 400 Bq/m3 in some dwellings. The arithmetical and geometric mean values of indoor radon concentration are 80 ± 77 Bq/m3 and 58 Bq/m3, respectively. The geometric mean value of radon measured by SSNTD is 101 Bq/m3. The distribution of areas with a high indoor radon concentration is spatially consistent with deep and large active faults or overlapping and intersection zones of multiple groups of faults. It is recommended to conduct a more comprehensive investigation and research into the elevated radon potential and radioactivity associated with building materials.