RESUMEN
Everyone is exposed to radon because it is present everywhere with varying concentrations. Radon and its progeny are well established as lung carcinogenic. Track etch technique using LR-115 plastic track detectors has been used to measure the effective radium content and radon exhalation rates in soil samples collected from urban area of Etah district of Uttar Pradesh province in Northern India. The values of effective radium content are found to vary from 27.87 to 45.14 Bq.kg-[1] with a mean value of 34.98 Bq.kg-[1]. The mass exhalation rates of radon vary from 2.38 _ 10[-6] to 3.86 _ 10[-6] Bq.kg[-1].d[-1] with a mean value of 2.99 _ 10-6 Bq.kg[-1].d[-1]. The surface exhalation rates of radon have been found to vary from 6.19 _ 10[-5] to 10.03 _ 10[-5] Bq.m [-2].d[-1] with a mean value of 7.77 _ 10[-5] Bq.m [-2].d[-1]. Radon exhalation study is important for understanding the relative contribution of the material to the total radon concentration found inside the dwellings. The values of radium and radon exhalation rates are found to be below the safe limit recommended by OECD, 1979