Modeling the 212Pb activity concentration in the lower atmosphere

A worldwide radionuclide network of 80 stations, part of the International Monitoring System, is being setup to monitor compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The radioactivity sampled at these stations is primarily 220Rn progenies affecting the detection capability. A model linking the 220Rn emanation with the sampled 212Pb activity was developed and is presented here. The model and the performed measurements show that the variation of the sampled 212Pb activity can be fully explained by the variation of the local 220Rn activity concentration.