Radon Activity Concentration In Air Research Articles

Soil and air radon/thoron exhalation rates and radon activity concentrations in the vicinity of Lake Monoun, West region of Cameroon

ABSTRACTOne crucial element to determine the radon amount in the environment is the rate at which radon is exhaled from the subsurface. To assess the radon and thoron potential exhalation in the vicinity of Monoun Lake in the West Region of Cameroon, 28 soil samples were collected around the lake. Radon activity concentration in soil gas and air and the related risk to radon inhalation were evaluated. Radon and thoron exhalation rates, mass exhalation rates, and radon soil gas activity concentrations were derived from a mathematical model as a function of radium content and soil parameters. Radium activity concentrations were estimated using a gamma-ray spectrometry technique with a High Purity Germanium detector (HPGe). The average radon exhalation rate, thoron exhalation rate, radon mass exhalation rate, and thoron mass exhalation rate were found to be 22.7 mBq.m−2.s−1, 5348 mBq.m−2.s−1, 0.018 mBq.kg−1.s−1, and 321 mBq.kg−1.s−1, respectively. The registered radon and thoron exhalation rates were above the world average values of 16 Bq.m−2.s−1 and 1000 Bq.m−2.s−1 published by UNSCEAR, respectively. The calculated thoron exhalation in the study area was about 75.3 times higher than that of radon, which suggests probably more exposure to thoron gas than the radon in the area, despite its shorter half-life. A good positive correlation was found between radon and thoron exhalation rates. The obtained average values of radon activity concentrations in air and annual effective dose were above the world average values of 10 Bq.m−3 and 0.095 mSv published by UNSCEAR, but still below the threshold values of 148 Bq.m−3 and 1.4 mSv set as action levels by USEPA, respectively.

Recent Progress in Radon Metrology at IFIN-HH, Romania

The practical implementation of the European Council Directive no. 2013/59/EURATOM in Romania requires reliable indoor measurements of the radon (222Rn) activity concentration in air. In Romania, several Testing Laboratories were designated for radon activity and/or radon activity concentration in air measurements by the Romanian National Commission for Nuclear Activities Control (CNCAN). The calibration of the instruments used for indoor radon activity concentration measurements is very important. IFIN-HH, through its Ionizing Radiation Metrology Laboratory (LMRI), performed advanced research in the field of radon metrology, using radon standard sources prepared by LMRI, its radon chamber facility and a new reference radon monitor. The most recent results are described in this article. The radon chamber facility from IFIN-HH was technically improved, and new equipment and methods were set up and tested in order to provide new calibration services for customers. Additionally, calibration of the radon monitors was performed, as well as of the systems with solid-state nuclear track detectors, used for radon in air activity concentration measurements. IFIN-HH/LMRI obtained the CNCAN designation as Calibration Laboratory for installations measuring the radon activity concentration in air.

New S-chamber Mid-Term electrets: Experimental characterization and uncertainty evaluation

Electret ion chambers are widely used passive detectors, employed for measurements of radon activity concentration in air. These devices are made of a Teflon electret coupled to an interchangeable ion chamber. A new type of electret produced by Rad Elec Inc., named Mid-Term, is used together with the S-type (200cm3) chamber. It is designed to be operated in an intermediate range with respect to the standard Short-Term and Long-Term electrets. This work describes the complete characterization of such device, performed according to the ISO guidelines. The characterization was carried out in the secondary standard calibration laboratory of Politecnico di Milano Italy, and with a traceable radon chamber. The coefficients and equations presented can be used by operators to assess both the radon activity concentration and the related uncertainty, with the only requirement of the knowledge of the background gamma air kerma rate of the specific measurement site and its related uncertainty.

Calibration of CR-39 for different heights of radon dosimeters and application of radon concentration in Mahajran River sediment in Basra Governorate, Iraq

Radon and its progenies are the main cause of lung cancer when they are trapped inside the lungs. Therefore, the radon activity concentration in air, water and soil samples should be measured, monitored and analysed. In this paper, river sediment samples collected from 30 different locations of Mahajran River, Basra, Iraq, were studied by using solid-state nuclear track detector type CR39. The track detector used for this purpose must be calibrated for concentrations of radon, Thoron and their daughters likely to be found in samples. The chamber used in the present calibration work had a volume of 125 L and contained a standard radon source (226Ra) and radon distribution fan. Results illustrated the dependence of the CR-39 calibration factor on the dosimeter height. The calibration factor used in this application was 0.34±0.0 Tr/cm2·day / Bq·m−3 for a height of 10 cm.

Measurements of radon activity concentration in mouse tissues and organs.

The purpose of this study is to investigate the biokinetics of inhaled radon, radon activity concentrations in mouse tissues and organs were determined after mice had been exposed to about 1MBq/m3 of radon in air. Radon activity concentrations in mouse blood and in other tissues and organs were measured with a liquid scintillation counter and with a well-type HP Ge detector, respectively. Radon activity concentration in mouse blood was 0.410 ± 0.016Bq/g when saturated with 1MBq/m3 of radon activity concentration in air. In addition, average partition coefficients obtained were 0.74 ± 0.19 for liver, 0.46 ± 0.13 for muscle, 9.09 ± 0.49 for adipose tissue, and 0.22 ± 0.04 for other organs. With these results, a value of 0.414 for the blood-to-air partition coefficient was calculated by means of our physiologically based pharmacokinetic model. The time variation of radon activity concentration in mouse blood during exposure to radon was also calculated. All results are compared in detail with those found in the literature.

Diagnostics techniques and dosimetric evaluations for environmental radioactivity investigations

A comprehensive study was conducted about the investigation of the natural/anthropo-genic radioactivity of various environmental matrices. Different diagnostics techniques were employed: high resolution HpGe gamma spectrometry, to quantify the activity concentration of radionuclides that emit gamma photons; alpha spectrometry, for the determination of the specific activity of α -emitters radioisotopes; liquid scintillation, to measure the activity concentration of tritium, radon and total alpha/beta in liquid samples; alpha spectrometry through the Rad7 setup, to estimate the gas radon activity concentration in air, water and soil; total alpha/beta counter, for the activity concentration quantification of radionuclides, in solid samples, emitting alpha/beta particles. From the dosimetric point of view, knowledge of the radioactivity level in the environmental matrices allows to evaluate any possible radiological hazard for the population, through the calculation of the appropriate parameters of radioprotection and their comparison with the safety limits reported by the literature.

Levels of Radon Activity Concentration in Air of Coal Mines in Bosnia and Hercegovina

By coal mining and exploatation, radioactive radon gas, which is captured in natural geological structures, is reallocated from the deep coal layers. Hence it is concentrated in the depots and coal seams of the mines or being transported to the surface of the earth where it can significantly change the levels of radioactivity in the working premises and residences. This paper presents the results of a three-year research of radon activity concentration in the air in hole and surface coal mines of Bosnia and Herzegovina. Detected concentrations of radon in the coal gaseous structure, atmosphere and other ambient media are in correlation with the properties of geological structures, technology for obtaining coal and meteo-climatic changes. They were measured with Alpha GUARD PQ 2000 radon portable measuring system (instruments Genitron-Frankfurt) and RadoMeter 2000 (Radosys LTD. Budapest), using the SS-NTD method.

Experimental study on the effect of high humidity environments on the response of long-term exposed nuclear track detectors

Abstract In Spain, a recent modification in the regulations of protection against ionizing radiation obligates to determine radon levels in particular workplaces like spas, mines and caves. Most of these workplaces may present extreme measurement conditions like high aerosol content, temperature, and humidity that can affect the radon detector response. In our laboratory we use to determine mean radon activity concentration in air with the nuclear track detector Makrofol DE covered with an aluminized Mylar foil and placed within the FzK FN diffusion chamber with a glass fibre filter. We have compared detector response using different filter configurations in common laboratory ambient conditions. The configuration with a better response (polyethylene filter) and our reference configuration took part in a study of the effect of different temperature and humidity on our detector response carried out in the INTE radon chamber. Results obtained did not show a significant difference between detector responses with both filters. However, when we exposed them for long periods to real environmental conditions at underground sites we could observe Mylar deterioration. To look in detail into a possible effect of long-term high-humidity exposures we exposed nine sets of detectors with three different polyethylene bags, first five sets under controlled conditions in the INTE radon chamber and then four sets in long-term exposures at high humidity environments. We have seen that the Mylar foil can be damaged depending on the duration of exposure. In a radon chamber exposure time is normally limited to a few days for practical and financial reasons; therefore, results do not show if humidity affects the glass fibre filter and detectors response. To analyse it we exposed detectors in a real humid environment up to a month where we already observed Mylar deterioration due to humidity but the possible impact on track density is hidden by the scattering of the results found, so a clear conclusion cannot be stated.

Radon activity concentration—a Euromet and BIPM supplementary comparison

For the first time, a comparison of radon activity concentration in air has been performed within the scope of Euromet. In the project 657, ‘Comparison of calibration facilities for the radon activity concentration,’ 12 participants from 9 countries compared different radon reference atmospheres at 1, 3 and 10 kBq m −3 via a transfer standard. The comparison was listed as BIPM supplementary comparison EUROMET.RI(II)-S1. The results of most participants are correlated due to common traceability to one single radon gas standard producer. This makes a careful correlation analysis necessary to achieve an appropriate comparison reference value. The results of the comparison as well as the complex analysis of the correlated set of data is presented and discussed.

Comparison of calibration facilities for radon activity concentration: Euromet Project 657

Prior to 2002, no comparisons of radon activity concentration had been performed within the scope of the EUROMET. The comparison presented here fulfils the need to provide confidence in the capability of national metrology institutes and calibration laboratories to measure radon activity concentration in air. This has been achieved by the measurement of radon reference atmospheres using an electronic, radon measuring instrument as the transfer comparison device (CD). Each of the twelve institutes, from nine countries, calibrated the CD using standard calibration procedures according to their quality system, at three different activity concentrations: 1 kBq/m3, 3 kBq/m3 and 10 kBq/m3. For each activity concentration, a comparison reference value and its uncertainty have been derived. From these the degrees of equivalence have been calculated and are presented graphically and in the form of matrices. All the results are consistent within the assigned uncertainties.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by EUROMET, according to the provisions of the Mutual Recognition Arrangement (MRA).

Measurement of the Potential Alpha Energy Concentration of Radon Daughters by Means of a Double Chamber System and Solid State Nuclear Track Detectors

The potential alpha energy concentration of radon daughters can be determined by means of the difference in the track densities measured with one unfiltered and one filtered solid state nuclear track detector within appropriate dosemeter chambers. Assuming a certain radon activity concentration in air, both the corresponding potential alpha energy concentration as well as the difference in the track density rates are functions of the equilibrium factor. Therefore, the dosemeter response also depends on the equilibrium factor. For a special type of double chamber the dosemeter response was calculated and experimentally investigated as a function of the equilibrium factor. The results show that the response is nearly constant within ±20% for equilibrium factors between 0.25 and 1. Conclusions are drawn on the conditions at which the dosemeter response can be approximated by a constant value. In this case the dosemeter calibration could easily be performed using active working level monitors.