Abstract: Abstract:In order to investigate the activity concentration level of radon in the stations of Changsha Metro Line 1, we have used typical sampling method and randomly selected 5 stations to measure and evaluated the radon activity concentration. With the aid of the track etched sheet, we have used accumulation method to investigate the radon activity concentration of the vehicle control room, platform and customer service center in the stations. The results showed that the activity concentration of radon in the stations of Changsha Metro Line 1 was in the range of 22.5-53.0 Bq/m³, with a mean value of 35.3 Bq/m³, which is only 5.6% deviation from the average radon activity concentration (37.4 Bq/m³) in Changsha city. The radon activity concentration was far below the restriction of Standard for controlling radon and its progenies in underground space, GBZ 116—2002 (Equilibrium Equivalent Radon Concentration 400 Bq/m³); The average dose of the staff and public caused by radon activity concentration in stations was 0.28 mSv and 0.08 mSv respectively. The average dose of the staff and public caused by radon concentration was at the background level, and meeting the requirements of the Basic Standards for Protection against Ionizing Radiation and for the safety of radiation sources, GB 18871—2002.

Key words: Changsha Metro Line 1, radon activity concentration, investigation