Contribution of radon to natural radiation environment in Uttaranchal

The radioactive nuclides are originated in earth's crust and present everywhere in the environment, including human body. The exposure of human being to ionizing radiation from natural sources is a continuous feather of life on the earth. Radon and its decay products in the atmosphere are the most important contributors to human exposure from natural sources. Radon and its daughter products present in man's natural radiation environment pose a significant hazard only when concentrated in some enclosures such as underground mines, caves, cellars or poorly ventilated houses. This paper presents a review of our work on radon studies in Garhwal and Kumaun region of Uttaranchal during last one decade. The results of radon measurements in soil-gas, groundwater and indoor environment in Garhwal and Kumaun areas are discussed in details. (author)