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 important component of the database required to set up guidelines and policy of controlling radon at home.

Radiometric evaluation of indoor radon levels with influence of building characteristics in residential homes from southwestern Nigeria

A Monte Carlo simulation of unmitigated risk of radon exposure from soil and groundwater around Maiganga Coal Mine, North-Eastern Nigeria

Introduction In this study, effective dose equivalent for the public due to internal exposure to 222radon (222Rn) was evaluated in three regions of Ramsar, a northern coastal city in Iran.                                Materials and Methods Measurements were carried out using a radon monitoring device. Outdoor and indoor radon concentrations were measured within 24 hours with an integration interval of 3 hours. Regions were selected with respect to our previous study on areas of Ramsar with high levels of environmental background radiation. Results This study showed that indoor 222Rn concentration reached to 465 Bq/m3 in one of the selected regions (Talesh Mahalleh) in early morning (5-8 a.m.). Our study also showed that the average effective dose equivalents (due to both indoor and outdoor exposures) in the selected regions (Talesh Mahalleh, Sadat Mahalleh, and Chaparsar) were 9.5±2.8, 5.1±2.1, and 3.2±1.2 mSv/y, respectively. Conclusion It is clear that the annual effective dose from internal exposure to 222Rn in areas of Ramsar with high levels of natural radiation was significantly higher than the maximum annual effective dose permissible for public.

http://ijmp.mums.ac.ir/article_4326_6d95f96b21ba72ddeb610e65d31dce21.pdf

Assessment of Effective Dose Equivalent from Internal Exposure to 222Rn in Ramsar City

Background & Objective: People who work in closed and underground environments such as mines get radioactive gases into their respiratory system due to the concentration in the air. These radioactive substances, after entering the body’s respiratory system, with radiating energetic particles, damage most of the live cells. The most damaged parts are in the alveolar air cells of the lung which may lead to cancer. 
Materials & Methods: The absorbed energy and annual effective dose due to the emitted alpha beam of radon and derivatives on alveolar air cells of the adult lung using MCNPX 2.6.0 simulation are determined. Color profiles are shown as a result of simulation of absorbed dose in the 27 alveoli of lung due to alpha radiation of radon and its derivatives. 
Results: The investigations show that polonium-210 (210Po), as one of the radon derivatives with long life, has the most annual effective absorbed dose in the human lung and as a result can cause the most damage to the living tissue of the alveolar air cells in comparison with the other radon derivatives. After this element, 218Po, 222Rn ,214Po and 214Bi have more the absorbed dose in the human lung, respectively. 
Conclusion: Most cancers from radon are generated by radon derivatives. They can play an important role in lung damage. Exposure to radon derivatives rises a person's lifetime risk of lung cancer. The risk increases in direct relationship with the length of exposure and the type of radon derivative. For reduction of 210Po is suggested the use of ventilation. It moves outdoor air into the building, and distributes the air within the building.

Determining the Absorbed Dose of Alpha Radiation due to Inhalation Radon Gas and Its Derivatives in Human Lung Using MCNPX 2.6.0 Simulation Model by Jafari et al. In Khorasan Razavi, Summer 2019

This review study examines the relationship between radon and geology, including its origins, transmission, and accumulation, as well as its impact on human health and mitigation strategies. The decay of uranium and thorium produces radon, a radioactive gas. Its concentration in the environment fluctuates based on local geology, soil permeability, climate, and terrain, as well as regional, seasonal, and daily meteorological conditions. Exposure to radon indoors is associated with an increased risk of lung cancer, making it a significant public health concern. Measuring radon concentrations in indoor environments is essential for identifying high-risk areas and devising effective mitigation strategies, such as ventilation, fissure sealing, and exhaust installation. The need for greater knowledge of regional and seasonal fluctuations in radon concentration, as well as the development of more effective and cost-effective measuring and mitigation strategies, has implications for future research. To influence public health policies and practices, more research on the long-term health effects of radon exposure is required. The focus of public health policy should be on increasing awareness of the dangers associated with radon exposure, supporting regular measurement and monitoring of radon concentrations in indoor areas, and encouraging the adoption of effective mitigation techniques. When selecting construction sites, urban planning regulations and building codes should consider the local geology and radon levels in the soil.

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The Relationship between Radon and Geology: Sources, Transport and Indoor Accumulation

Introduction: Internal exposure to radon gas progeny can lead to serious biologic damages to the lung tissue. The aim of this study was to evaluate the absorbed dose by lung tissue due to the exposure from short-lived radioactive products of radon (222Rn) decay using Monte Carlo simulation. Material and Methods: A lung equivalent phantom including 64 air sacs was simulated by MCNPX code. Then, the absorbed dose from short-lived radioactive products of radon decay chain including 218Po, 214Po, 214Pb and 214Bi was calculated for both suspended and deposited states of daughter nuclides inside the lung. Results: The results showed that alpha decay has more contribution to the lung absorbed dose in comparison with the beta and gamma decay. Furthermore, the received dose by the lung was higher when the radon progenies were deposited inside the lung so that the maximum received dose to lung was 100 times higher than that of calculated in suspended state. Conclusion: Short-lived daughter radionuclides of radon decay chain, especially alpha emitter products, can be considered as dangerous internal radiation sources. The biological effects of these daughter radionuclides is more severe when are suspended inside the respiratory system.

http://ijmp.mums.ac.ir/article_12971_70012f816da4f4b9e0c689ab9f0e5404.pdf

Zohreh Danaei

Papers

Absorbed Dose Assessment from Short-Lived Radionuclides of Radon (222Rn) Decay Chain in Lung Tissue: A Monte Carlo Study