Variation of radon progeny concentration over a continental location

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

Indoor 222Rn and 220Rn variations: evidence for Boyle's law

Radon and its daughter product are a major source of natural radiation exposure, the measurement of radon concentration in dwellings is assuming ever increasing importance. It is known from recent surveys in many countries that radon and its progeny contributes significantly to total inhalation dose and is well established that radon when inhaled in large quantity causes lung disorder. In view of this the authors have measured 222Rn and 220Rn levels in dwellings of different volumes at Bangalore Metropolitan, India. Integrated and long duration measurements of radon were carried out using twin cup dosimeters with Solid State Nuclear Track Detector technique. Results showed that concentrations of 222Rn, 220Rn, their progenies and dose rates in dwellings decreased with increase in room volume. Conclusions: The annual effective inhalation dose due to 222Rn, 220Rn and their progenies from the study ranged between 0.2-4.4 with an arithmetic mean of 1.7 +/- 1.1 mSv y-1. The dwellers of lower volumes are posed to high dose rates

Concentration of radon, thoron and their progeny levels in different types of floorings, walls, rooms and building materials

Radon, thoron and their progenies are the most important contributions to human exposure from natural sources. Radon exists in soil gas, building materials, Indoor atmosphere etc. Among all the natural sources of radiation dose to human beings, inhalation of radon contributes a lot. The work presented here emphasizes the long term measurements of radon, thoron and their progeny concentrations in about 100 dwellings using solid state nuclear track detectors. Measurements were made using dosimeters and the concentrations were estimated by knowing the track density of films through spark counter, and sensitivity factor for bare, filter and membrane films. Presence of radon and thoron in houses is the effect of several aspects such as the activity concentrations of uranium, radium and thorium in the local soil, building materials, ventilation of houses and also entry of radon into houses through the cracks in floor/wall. The observations reveal that the concentrations of radon and/or thoron are relatively higher in granite than in concrete, cement and bricks. In continuation to this the concentration observed in bathrooms is more compared to kitchen, bedroom and living rooms. This study discloses that the residential rooms of good ventilation will avoid the health hazards due to radon and its rich materials