A special laboratory was built for the research on 222 Rn and 220 Rn mitigation by depressurization of concrete wall of high rise buildings in Hong Kong. Reduction of 222 Rn and 220 Rn exhalation rate from concrete wall was studied by embedding tunnels in a concrete wall and pumping away the 222 Rn and 220 Rn in the wall. The reduction in exhalation rate was quantified against the applied depressurization and the distance from the pumping tunnel. 220 Rn exhalation rate was measured by passive and integration 220 Rn dosimeters with absorber. Results show that 220 Rn exhalation rate from concret...
