Measurements of 222 Rn, 220 Rn and their progeny concentrations indoors around a coal/gas-based power plant and estimati
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Measurements of 222Rn, 220Rn and their progeny concentrations indoors around a coal/gas‑based power plant and estimation of annual inhalation dose to the public Mukesh Kumar1 · Pankaj Kumar1 · Anshu Agrawal2 · B. K. Sahoo3 Received: 12 January 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract In the present study, indoor radon (222Rn), thoron (220Rn), radon progeny (214Po) and thoron progeny (212Po) activity concentration have been measured in a region around the National Capital Power Station, Dadri, Uttar Pradesh, India. The mean values of the 222Rn, 220Rn and their progeny in the studied region are found to be 22.1 ± 10.0 Bqm−3, 48.6 ± 13.5 Bqm−3, 8.8 ± 4.8 Bqm−3 and 0.49 ± 0.15Bqm−3 respectively. The annual inhalation dose estimated from the observed concentrations varies from 0.29 ± 0.04 to 2.06 ± 0.121 mSv with a mean value of 0.75 ± 0.32 mSv and is well within the reference level. It has also been observed that 212Po is a significant contributor (= 18.7%) to the total annual inhalation dose. Seasonal variations of 222Rn, 220Rn, and their progeny have also been reported. Keywords Radon · Thoron · Single entry pin-hole cup dosimeter · DTPS · DRPS · Annual inhalation dose
Introduction Radon (222Rn), Thoron (220Rn) and their progeny are the most important sources of natural radiation and their inhalation contributes more than half (~ 52%) of the natural background radiation dose to the general public [1]. A significant positive correlation between 222Rn exposure in the home and lung cancer has been reported by various studies [2–7]. Therefore, reliable time-integrated measurements of the annual averaged radon and thoron levels indoors are required . 222Rn and 220Rn are the only radioactive gaseous elements arising in 238U and 232Th series, respectively. Underground soil and construction materials, whether natural, manmade, or by-products are the important sources of 222 Rn and 220Rn inside a building, as they contain variable amounts of naturally occurring radionuclides such as the * Mukesh Kumar [email protected] 1
Department of Physics, S.V. College, Aligarh, U.P. 202001, India
2
Department of Chemistry, D.S. College, Aligarh, U.P. 202001, India
3
Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, India
decay chain of 238U and 232Th. However, their indoor activity mainly depends on the local geology, air exchange rate, size, and structure of the dwellings. Diffusion and pressure-driven flow from the ground beneath and building materials are the processes by which 222Rn (or 220Rn) can enter a house [8]. However, it is believed that the dominant transport mechanism in the building materials is diffusion [9]. Industrial activities, like coal (or natural gas)—fired plants may further modify the radiation exposure of the population living in the vicinity of plants. Coal and natural gas contain trace quantities of 238U, 232Th, and their decay products [10–12]. By burning coal (or natural gas), the activities of these naturally occurring radionuclides
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