By daughters we mean the radon short lived pregonies

For single measurements, we use the method involving air filter gross beta counting. The method is based on the total aerosol sampling on filters and immediate gross beta counting of 214 Pb and 214Bi activities. . Measurements are interpreted according to a Raabe – Wrennand Jacobi simplified room model, leading to an estimate of the individual airborne activities of short-lived radon daughters, the removal parameter and the equilibrium factor. 

Thank you very much Dr. Massimo Favre Ragan 

For the attachment and answer. 

Radontrapping is done by keeping cage (with filter). We were keeping in houses for few months where the radon level was more.

A simple method is to employ bare  CR-39 and LR-115 detectors together with enclosed in calibrated cups.

Nevertheless this method is sensitive to the aerosol size distribution and its evolution with time.

Thank you very much Dr. Dimitrios for your answer.