Radiometric evaluation of indoor radon levels with influence of building characteristics in residential homes from south
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Radiometric evaluation of indoor radon levels with influence of building characteristics in residential homes from southwestern Nigeria Kehinde Aladeniyi & Adeseye Muyiwa Arogunjo & Alcides J. S. C. Pereira & Oladele Samuel Ajayi & Ibiyinka Agboola Fuwape
Received: 3 September 2020 / Accepted: 10 November 2020 # Springer Nature Switzerland AG 2020
Abstract Indoor radon (222Rn) measurements were carried out using solid state nuclear track detectors (SSNTD) in some dwellings from southwestern Nigeria. This was aimed at statistically assessing influence of building characteristics on the measured radon and estimating excess lifetime cancer risks (ELCR). The measured radon concentrations followed lognormal distribution and were significantly influenced by some building properties. The arithmetic mean (1.60 mSv) of annual effective doses (AEDs) due to indoor radon was observed to be higher than the world average level (1.15 mSv) but less than lower limit (3 mSv) of International Commission on Radiological Protection (ICRP). The evaluated excess lifetime cancer risk ranged from 1.5 to 28.1 (MPy)−1 with an average value of 6.3 (MPy)−1, indicating that after exposure to indoor radon for 70 years, 6 people in every 1000 are likely to suffer the risk of developing lung cancer. Adequate ventilation systems were recommended for houses with high level of radon to avoid unnecessary exposure to radon. However, the investigated data would form
K. Aladeniyi (*) : A. M. Arogunjo : O. S. Ajayi : I. A. Fuwape Department of Physics, Federal University of Technology, Akure, Ondo State, Nigeria e-mail: [email protected] e-mail: [email protected] A. J. S. C. Pereira CITEUC Department or Earth Science, University of Coimbra, Coimbra, Portugal
important component of the database required to set up guidelines and policy of controlling radon at home. Keywords Indoor radon . Lung cancer . Dwellings . Building characteristics . Excess life cancer risks
Introduction Radon is a naturally occurring radioactive gas which cannot be detected by human sense organs. It has three major isotopes which are radon, 222Rn (T1/2 = 3.82 days), thoron, 220Rn (T1/2 = 55.6 s), and actinon, 219Rn (T1/2 = 3.6 s) which occur in the natural decay series of 238U, 232 Th, and 235U, respectively (Kıldır et al. 2016; Lee et al. 2017; Sivakumar 2018; UNSCEAR 2000). Among the isotopes, 222Rn (a direct daughter of 226Ra in the decay series of 238U) is the most important from the radiological protection point of view because it is not only ubiquitous but also alpha-emitting gas. It has crucial impacts on human health when inhaled for over a long period of time, especially in radon-accumulated enclosures (such as caves, mines, and poorly ventilated dwellings). It is mainly emitted from the soil and rocks underneath buildings, building materials, water, and natural gases (Tan and Xiao 2013). Outdoor radon does not constitute major risk due to dilution with other atmospheric gases. However, radon becomes a major threat when it is emitted indoors and gets acc
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