Alpha flux radiated from 222Rn, 220Rn and progeny is the primary contributor of natural radioactivity to the inhabitants in the ambient atmosphere. The annual indoor 222Rn and 220Rn concentrations were found to be 85 ± 43 and 84 ± 36 Bq m−3, respectively. The estimated annual indoor 222Rn and 220Rn concentration is below to reference value of 100 Bq m−3 suggested by WHO. The calculated annual inhalation dose due to exposure to the alpha flux of 222Rn, 220Rn and their progeny is well below the recommended reference level given by UNSCEAR and ICRP. The data were further checked for normalisation and found that 222Rn and Effective Equilibrium Radon Concentration (EERC) data are not normally distributed.