In recent years a number of case-control epidemiological studies have taken place and others are inprogress to evaluate the lung cancer risk to the general population from exposure to radon and itsshort-lived progeny in the indoor residential environment. While it is actually long term exposure overpast decades to radon progeny by inhalation that dominates lung doses, for a number of practicalreasons it is radon gas that is measured in these studies.
Radon and thoron and their decay products are the most important sources of radiation exposure to thegeneral public, contributing on average about half of the total effective dose equivalent received fromnatural and man-made radioactivity, such situation is encountered also in Poland. The short-liveddecay products of 222Rn decay to 210Pb with half-life of 22 years contribute to the inhaled effectivedose of man.The estimation of radon risk in Poland is made on the basis of radon concentration in soil gas.