A Review of Radon Equilibrium Factors in Underground Mines, Caves, and Thermal Spas

Chen, Jing; Harley, Naomi H.

doi:10.1097/hp.0000000000001214

Cited by 9 publications

(9 citation statements)

References 59 publications

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“…These values differ from the ICRP recommendation in caves of F eq = 0.4 [9]. Many studies in caves around the world have similarly reported that the F eq evaluated differed from the recommended F eq [18,19,[35][36][37], however, and Chen and Harley [17] concluded that the recommended F eq value should be used with the understanding that its variability in actual caves can be more than ±50%. On the other hand, the arithmetic mean (±standard deviation) of the respective measurements for summer and winter is 0.33 ± 0.20, and the annual average from the seasonal average is 0.40.…”

Section: Discussionmentioning

confidence: 79%

“…Cigna [16] has summarized reports on F eq in caves by 12 researchers (the number of measurements was more than 880) and stated that the weighted average of F eq was 0.57. Chen and Harley [17] also summarized reports on F eq in a total of 136 underground show caves, tourist mines and thermal spas in 17 countries and noted that F eq varied from 0.10 to 0.85 and the weighted average was 0.39. Moreover, it is important to evaluate F eq in different seasons, as several studies have reported seasonal variation [18,19].…”

Section: Introductionmentioning

confidence: 99%

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A Preliminary Study of Radon Equilibrium Factor at a Tourist Cave in Okinawa, Japan

et al. 2021

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The International Commission on Radiological Protection (ICRP) issued its Publication 137, Occupational Intakes of Radionuclides: Part 3 in which the radon equilibrium factor is fixed as 0.4 for tourist caves; however, several studies have reported a different value for the factor and its seasonal variation has also been observed. In this study, the radon concentration, equilibrium equivalent radon concentration and meteorological data were measured, and the equilibrium factor was evaluated in a tourist cave, Gyokusen-do Cave located in the southern part of Okinawa Island in southwestern Japan. Radon concentrations were measured with an AlphaGUARD and their corresponding meteorological data were measured with integrated sensors. Equilibrium equivalent radon concentration was measured with a continuous air monitor. The measured radon concentrations tended to be low in winter and high in summer, which is similar to previously obtained results. By contrast, the equilibrium factor tended to be high in winter (0.55 ± 0.09) and low in summer (0.24 ± 0.15), with a particularly large fluctuation in summer. It was concluded that measurements in different seasons are necessary for proper evaluation of radon equilibrium factor.

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Section: Discussionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

A Preliminary Study of Radon Equilibrium Factor at a Tourist Cave in Okinawa, Japan

et al. 2021

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“…According to the ICRP report [ 10 ], the equilibrium factors for a reference worker (average breathing rate of 1.2 m 3 /h) are equal to 0.4 in indoor workplaces, 0.2 in mines, and 0.4 in tourist caves. As has been shown in different studies, the equilibrium factors can differ considerably from the values mentioned above [ 12 , 13 , 14 ], especially when mechanical ventilation is applied. According to a comprehensive study carried out by Chen and Harley [ 12 ], the equilibrium factors varied from 0.08 to 0.72 for active mines in 18 countries and from 0.10 to 0.85 for caves, tourist mines, and thermal spas.…”

Section: Introductionmentioning

confidence: 94%

“…As has been shown in different studies, the equilibrium factors can differ considerably from the values mentioned above [ 12 , 13 , 14 ], especially when mechanical ventilation is applied. According to a comprehensive study carried out by Chen and Harley [ 12 ], the equilibrium factors varied from 0.08 to 0.72 for active mines in 18 countries and from 0.10 to 0.85 for caves, tourist mines, and thermal spas. For this reason, it is much better to use active devices with a filtration system to directly measure the potential alpha energy concentration (PAEC), which can then be used to evaluate the appropriate dose directly.…”

Section: Introductionmentioning

confidence: 94%

Modeling: Activity Concentration of Radon, Thoron, and Their Decay Products in Closed Systems

Skubacz

Michalik²

2022

IJERPH

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The article presents a model for simulating changes in the activity concentration of radon and thoron as well as their progeny in closed or poorly ventilated systems. A system can be considered closed when a stream of radon and thoron flows into a space, but nothing comes out. It was also assumed that there may be devices or installations with a filtering system that would reduce the concentration of radon and thoron decay products. These assumptions may, therefore, correspond to a situation in which, in an isolated chamber, the calibration of radon hazard-monitoring devices is carried out, and nuclides are supplied from an emanation or flow through sources or well-isolated spaces in an environment where the source of nuclides is, for example, radon and thoron exhalation. The differential equations were formulated on the basis of the assumption that the activity concentration of radionuclides of concern in the space is uniform. The equations do not consider possible losses due to diffusion or the inertial or gravitational deposition of aerosols. If these phenomena have a limited impact on changes in the activity concentration of nuclides, the solutions provided may be used to simulate the activity concentration of radon and thoron and their decay products in any confined space assuming different boundary conditions.

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“…The inhalation of the short-lived solid radon decay products and subsequent deposition on the walls of the airway epithelium of the bronchial tree deliver most of the radiation dose to humans. The equilibrium factor, F , between radon and its short-lived progeny in underground mine atmospheres can be very unstable and vary in space and time in the range of 0.1–1.0 ( Chen and Harley 2020 ). Therefore, some radon measurements in mines were direct measurements of radon progeny concentration in working level (WL) (1 WL = 2.08 × 10 −5 J m −3 ) or potential alpha energy concentration (PAEC, in units of J m −3 ).…”

Section: Review Of Radon Concentrations In Underground Non-uranium Minesmentioning

confidence: 99%

A Review of Radon Exposure in Non-uranium Mines—Estimation of Potential Radon Exposure in Canadian Mines

Chen

2023

Health Physics

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A worldwide review of radon exposure in non-uranium mines was conducted. Based on the reported radon measurements in a total of 474 underground non-uranium mines, the average radon concentration in underground non-uranium mines was calculated to be 570 Bq m −3 (varied from below detection limit to above 10,000 Bq m −3 ), and the average equilibrium factor between radon and its short-lived progeny was 0.34 (varied from 0.02 to 0.9). Using the average values from the review, annual effective radon doses to workers in Canadian non-uranium mines were estimated. For underground workers, the estimated annual effective radon dose to non-uranium miners was 3.8 mSv with the possibility of varying from 0.22 to 10 mSv depending on ventilation and other operation conditions. In Canada, the majority of mines are open-pit surface mines; only a small portion of the workforce in non-uranium mines physically work underground where radon concentration can be elevated. Averaged over the entire mining workforce, occupational exposure to radon in non-uranium mines is estimated to be 0.9 mSv. The results of this study indicate that there is potential for workers in non-uranium mines to reach or exceed Canadian thresholds for mandatory monitoring and reporting radiation doses, at least for underground operations.

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A Review of Radon Equilibrium Factors in Underground Mines, Caves, and Thermal Spas

Cited by 9 publications

References 59 publications

A Preliminary Study of Radon Equilibrium Factor at a Tourist Cave in Okinawa, Japan

A Preliminary Study of Radon Equilibrium Factor at a Tourist Cave in Okinawa, Japan

Modeling: Activity Concentration of Radon, Thoron, and Their Decay Products in Closed Systems

A Review of Radon Exposure in Non-uranium Mines—Estimation of Potential Radon Exposure in Canadian Mines

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