222Rn is an α-emitting radioactive noble gas produced by the decay of 226Ra,both being members of the 238U decay chain.222Rn concentrations in soil gas due to continuous 226Ra decay could be very high,with values up to several tens of thousands Bq m-3.Alpha-and beta-activities per unit volume of air due to radon (222Rn),thoron (220Rn) and their progenies were measured in air at different locations inside a karstic cave by using both CR-39 and LR-115 type Ⅱ solid state nuclear track detectors (SSNTDs).In addition,the concentration of the attached and unattached short-lived radon decay products were determined in the studied cave.The committed equivalent doses due to the attached and unattached fractions of 218Po and 214Po radon short-lived progeny were evaluated in different tissues of the respiratory tract of speleologists from the inhalation of outdoor air.Annual effective dose due to radon short-lived progeny from the inhalation of air by speleologists inside the studied cave was estimated.