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Background: Humans beings are continuously exposed to ionizing radiation from natural sources. The main contributors to natural radiation are high-energy cosmic radiation and radioactive nuclides that originates in the earth’s crust. Exposure to high levels of radiation can cause serious health effects. In this study an attempt has been made to monitor the levels of environmental background radiation (gamma) in temples, historical monuments, schools and colleges, hostels, wedding halls and theaters in Mysore and Chamaraj Nagar districts and assess the possible effects on environment and human health. Materials and Methods: Environmental radiation dosimeter is used to measure the outdoor and indoor radiation absorbed dose levels. The measurements were made 1 m above the ground level. Results: Inside the temples it varies from 122.7 to 231.4 nGy.h–1 with a median of 130.1 nGy.h–1 outside the temples it varies from 141.8 to 340.2 nGy.h–1 with a median of 216.2 nGy.h–1. In different types of buildings in indoor atmosphere it varies from 112.2 to 197.5 nGy.h–1 with a median of 127.0 nGy.h–1 and in outdoor atmosphere it varies from 140.9 to 298.4 nGy.h–1 with a median of 216.2 nGy.h–1. Conclusion: The indoor absorbed dose rate is higher than outdoors in all types of constructions. Indoor and outdoor environment of the temples has higher levels of radiation than the historical monuments and other public and private building in Mysore and Chamaraj Nagar districts. Use of additional granite materials inside or outside the building will enhance the absorbed radiation dose levels. The values observed in the study area are comparable with other values observed in different parts of the world.

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Background: The variation of the radon progeny concentration in outdoor environment and meteorological parameters at fine resolution were studied for one year at a continental location, National Atmospheric Research Laboratory, Gadanki, India.  Materials and Methods: The concentrations were measured using Alpha Progeny Meter by collecting air samples at a height of 1 m above the Earth’s surface at a known flow rate. Results: Radon progeny concentration shows temporal variations on diurnal and monthly scales, and is due to mixing in the atmosphere. Peak in the early morning hours and low values during afternoon compared to nighttime are due to differential heat contrast between earth’s surface and its atmosphere. However, the activity during February shows maximum compared to June/July months.  The diurnal variation of radon progeny shows positive correlation with the relative humidity and negative correlation with ambient temperature.  The monthly mean activity of radon progeny for the year 2012 was found to be 4.76 ± 0.73 mWL. Conclusion: The mean concentration of radon progeny in the study region is relatively high compared to the other locations in India and may be due to the rocky terrains and trapping of air-masses near the observation site due to its topography.