Annual inhalation dose of indoor radon in dwellings in Aizawl City, Mizoram, India

Abstract

Radon gas is found in the environment, indoor and outdoor and its parent element being traced back to U238. Study of indoor radon inhalation dose have been carried out in Aizawl City, Mizoram, India in 24 dwellings, which were specifically selected according to the site location of the dwell-ings. Solid-state nuclear track detectors (SSNTD) have been used to obtain the time integrated concentration levels of indoor radon. DRPS (direct radon progeny sensor), which selectively regis-ter the tracks due to alpha emissions from 214Po from the deposited atoms of 222Rn progeny species is used for estimating the equilibrium equivalent radon concentration (EERC). The equilibrium factor (F-factor) for radon is then calculated using the measured EERC and concentrations of ra-don. The equilibrium factor may be defined as ratio of the amount of progeny nucleus to that of a parent nucleus. Inhalation dose has been obtained from the measured F-factor and concentrations of indoor radon. The data obtained in the present work has been analyzed to obtain the significant inhalation dose of indoor radon. From these observations it has been found that the annual inhala-tion dose of indoor radon in the study area is 624.89 Sv/y, which is low in comparison to the global average.