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Showing 4 results for Progeny
Dr. K. Kant, Rashmi, R.g. Sonkawade, G.s. Sharma, R.p. Chauhan, S.k. Chakarvarti,
Volume 7, Issue 2 (9-2009)
Abstract
Background: Radon and thoron are invisible, odorless, heavy and radioactive gases which are ubiquitously present in dwellings and in the environment. In the present work, seasonal variation of indoor radon, thoron and their progeny concentrations has been studied in the dwellings of industrially polluted cities in District Faridabad, Haryana and District Mathura in Uttar Pradesh. Materials and Methods: LR -115, Type- II (Kodak Pathe, France), peelable, plastic track detectors commonly known as solid state nuclear track detectors (SSNTDs) were used to measure the radon thoron concentration over long integrated times. The measurements were carried out in the mixed field of radon and thoron and the detectors were exposed for about 90 days. Results: The average value of radon and thoron concentration in the dwellings varied from 23.5 Bq/m3 to 65.2 Bq/m3 and 9.8 Bq/m3 to 18.7 Bq/m3 respectively in different seasons. The average annual exposure and annual effective dose in living rooms due to radon and thoron progeny was estimated to be 0.195 WLM (working level month) and 0.74 mSv respectively. The average life time fatality risk of lung cancer from the chronic radon and thoron progeny exposure was estimated to be 5.8 ´ 10-3 (0.58%). Conclusion: The seasonal variations of measured radon levels in the environment of LPG bottling plant, radon-thoron levels and inhalation dose due to radon and thoron and their progeny in dwellings indicate that the levels were higher in winter (October to January) than in summer (April to July). Iran. J. Radiat. Res., 2009 7 (2): 79-84
Dr. R. Sivakumar,
Volume 8, Issue 3 (12-2010)
Abstract
Background: Decay products of radon and
thoron present in indoor environment are the most
important sources of radiation from natural sources
which affect human beings, since general public
spend at lest 80% of their time in indoor. Materials
and Methods: Air samples were collected for
measuring the concentration of radon and thoron
daughter products from various indoor environments
during four different seasons of the year from the
Gudalore taluk of Nilgiri Biosphere using high volume air
sampler. The concentration of decay products of radon
and thoron were estimated using an alpha counter.
Results: Studies have revealed that the annual average
potential alpha energy concentrations of radon and
thoron progeny in dwellings of Gudalore were recorded as
3.54 and 2.65 mWL respectively. It was also observed
that the potential alpha energy concentration (PAEC)
values for radon progeny undergo dramatic change with
the change of season perhaps due to different aerosol
contents in the air. The maximum 222Rn (3.93 mWL) and
220Rn (3.10 mWL) progeny concentrations were observed
during winter months and the minimum values (222Rn
3.14 mWL and 220Rn 2.20 mWL) were observed
during summer. Conclusion: Studies have shown that
the dwelling with mud wall registered high value of
radon and thoron progenies (5.49 mWL and 3.88
mWL). While low values were observed in dwellings
with vinyl floor. High concentrations of radon and
thoron progeny were observed between 3.00 to 5.00
Hrs, while low values were observed at 14.00 hrs.
Studies suggest that radiation emission from radon
and thoron daughter in the study area were remained
well below the recommended level. Iran. J. Radiat.
Res., 2010 8 (3): 149-154
K. Charan Kumar, T. Rajendra Prasad, T. Narayana Rao, M. Venkataratnam, Dr. K. Nagaraja,
Volume 14, Issue 2 (4-2016)
Abstract
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.
Phd., B. Rawaa, S. Al Tarabichi ,
Volume 17, Issue 4 (10-2019)
Abstract
Background: Ondo Estimating the health effect of 222Rn progeny deposited on inner surfaces of airways regions is of great interest because 222Rn progeny are considered the major contributors in imparted energy to lung structures. Materials and Methods: In this study, (CT) scan of a healthy, non-smoking Syrian volunteer male, 3D-Slicer 4.7.0 medical image processing software, Solidworks mechanical design software and MCNPX 2.5.B code were used to create the geometry and to evaluate the absorbed fraction and specific energy due to alpha particles emitted by inhaled radon progeny in nuclei and layers of sensitive cells in the epithelium of human trachea-bronchial tree. Absorbed fraction (AF) and specific energy were determined using Micro-dosimetry approach and airway tube wall as proposed by ICRP (1994), and NRC (1991). Results: Absorbed fractions (AFs) and specific energy of alpha particles were calculated for each generation from 1st to 15th. Comparison of average AFs values in sensitive layers was carried out with ICRP66 airway model where some significant differences were found due to dimensions differences between both models. Furthermore, AFs of cell nuclei had the same trend of those for layers, where the highest values were for 7.69 MeV alpha particles in BB region and the opposite in bb region. Conclusion: Interactions of alpha particles with secretory and basal cells show significant differences which can influence dose weightings. Comparisons with ICRP66 data reveal the influence of geometry and target cells distribution on absorbed fraction and specific energy values.
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