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Sample records for 220rn exhalation rates

  1. Effect of ventilation rate on 220Rn concentration distribution in a model house

    In recent year, the dose associated with thoron and its decay products has gained considerable attention in India. This is mainly due to increasing awareness of thoron issue in coastal regions of India commonly known as High Background Radiation Areas (HBRAs) as well as in thorium and 232U handling occupational facilities. Thoron profiling is an important aspect for thoron dosimetry in these environments. Thoron (220Rn) is being a short lived (∼ 55 sec) element; it has been presumed that 220Rn concentration distribution pattern would not be significantly affected by ventilation rate. That is why higher value of 220Rn concentration was assumed near to the source such as wall etc. while beyond a particular distance no significant value of 222Rn concentration could be observed. To investigate the effect of ventilation rate on 220Rn concentration distribution, a controlled experimental study was carried out in laboratory model house at ISS, Germany at different ventilation rate of 0.5 h-1, 4.5 h-1 and 9.0 h-1. The model house of dimensions 2.8 m x 1.5 m x 1.8 m has one door and two windows in one of the long sides, is made of from unburned adobe bricks which are plastered with thick clay layer homogeneously enriched with powered granite. For obtaining the 220Rn concentration profile, 220Rn concentration was measured at different positions using sampling cup and indigenously developed portable thoron monitor (STM). It has been observed that 220Rn concentration profile itself varies with the ventilation rate. At the ventilation rate of 0.5 h-1 a gradient in 220Rn concentration profile was observed. 220Rn concentration was found higher near to the wall and decreasing towards the centre. On the contrary, at high ventilation rate of 4.5 h-1 and 9.0 h-1, a distorted 220Rn concentration profile was observed. This is due to the turbulent mixing caused by high ventilation rate. Hence, it can be emphasized that turbulent mixing plays a crucial role in deciding 220Rn

  2. Horizontal and vertical distribution of 222Rn and 220Rn in a dwelling, Bangalore, India

    The 222Rn and 220Rn have been identified as potential radiological health hazards and the dose estimation due to their exposure is an important task. Understanding their behavior in indoor environment helps in calculating the inhalation doses due to them. Effective doses due to inhalation of indoor 222Rn and its progeny account on an average for about one-half of all natural sources of radiation. However, recently the indoor surveys in Asia revealed that the dose contribution from 220Rn and its progeny can be equal to or even exceed that of 222Rn and its progeny. In view of this an attempt has been made to observe the distribution of 222Rn and 220Rn levels in a typical dwelling for the environment of Bangalore Metropolitan, India. Present study aims at the distribution of 222Rn and 220Rn concentrations in a typical dwelling. Higher concentrations were observed at the wall and flooring of the room and the concentrations were found to decrease as the detector is moved away from walls and floorings. The concentration of 222Rn is found to be invariant in indoor environment. An attempt has also been made to study the horizontal and vertical distribution pattern of 220Rn in a dwelling. The 220Rn concentration is found to drop exponentially as a function of distance from the source (wall/floor). Solution of one dimensional diffusion equation is used for regression fittings for 220Rn variation, from which the diffusion constants and the exhalation rates were calculated. The diffusion constants varied from 0.00195 to 0.00540 m2s-1. Results are discussed in detail

  3. Dose rate due to 226Ra, 232Th and indoor 222Rn/220Rn in Bangalore city

    Human beings have always been exposed to ionizing radiation from various natural sources of radiation and one of the major routes of internal exposures is through inhalation of radioactivity present in the atmosphere. External exposure is caused by the gamma radiation from 40K and the daughter products of 238U and 232Th. It is known that as a result of inhalation of 222Rn a daughter product of decay chain of 238U and its daughter products, the equivalent dose to the entire lung is 20% and 45% higher than the equivalent dose in other tissues. The present study is carried out in Bangalore Metropolitan, India during 2007 to till date. Activity concentrations were measured by hyper pure germanium detectors and 222Rn, 220Rn concentrations were measured by solid state nuclear track detectors. The dose conversion factors reported by UNSCEAR have been used to estimate the indoor inhalation dose rates. The absorbed dose rates due to 226Ra and 232Th ranged between 0.59 and 1.44 mSvy-1 with an AM as 0.93 mSvy-1. Whereas the dose rates during winter and summer ranged between 0.20 and 4.14 mSvy-1 with an arithmetic value 1.8 and 0.7 mSvy-1 respectively. The dose rates in lower volume rooms were ranged from 2.38 to 3.47 mSvy-1 and from 0.75 and 3.28 mSvy-1 for the rooms of higher volume. The arithmetic mean values of dose rates in lower and higher volume rooms were 2.94 ± 0.14 mSvy-1 and 1.35 ± 0.03 mSvy-1 respectively. Higher concentrations were observed in lower volume rooms than higher volume room of all the monitored locations. The detailed experimental methodology and results are discussed. (author)

  4. Thoron (220Rn) in the indoor environment

    Many locations around the world have higher levels of natural background radiation due to elevated levels of primordial radio nuclides in the soil and their decay products, like radon (222Rn), and thoron (220Rn) in the environment. Of late, technologically enhanced naturally occurring radioactive material has also contributed to the burden of background radiation. Since the contribution from inhalation of 222Rn, 220Rn and their short lived progenies contributes more than 54% of the total background radiation dose, it was necessary to supplement the external component with inhalation component. This component is not adequately estimated for the country so far on a national level. With this in mind, a national survey has been executed by this center involving a large number of universities and other allied research institutions from different parts of the country for the estimation of inhalation component of the dose rate arises from 222Rn, 220Rn and their short-lived progenies. This survey has been carried out using a twin cup radon-thoron dosimeter with solid state nuclear track based dosimeter developed and standardized at Bhabha Atomic Research Centre, Mumbai using LR-115 Type-II, of 12μm thick cellulose nitrate film as a detector. In this paper the contribution from 220Rn and its progenies to the inhalation component is presented. Present study reveals that 220Rn and its progeny contributes nearly 20% of the total dose rate to radon, thoron and their progenies. Paper presents the method measurements and the results obtained. Data available in literature is also compared. (author)

  5. 220Rn in geothermal steam

    The isotope 220Rn (half-life 56 seconds) occurs in fumaroles in Japan and Taiwan, in amounts as high as 1000 times the 222Rn content. The authors report its presence in geothermal steam at Wairakei, New Zealand, in amounts as high as 130 times those of 222Rn. It is detected by a radiochemical separation of Pb, and gamma spectrometry. Some of the 220Rn/222Rn ratios are higher than theoretically expected, but have frequently been reported from similar locations. Theories of possible origins will be discussed. 22 refs., 1 tab

  6. Response of AlphaGUARD radon detector to 220Rn

    Based on optimized-design ionization chamber, AlphaGUARD is the most stable commercial radon detector, which is widely used in various radon chambers worldwide as a standard device. Under ordinary radon concentration, it works according to the principle of pulse ionization chamber which only records the α particle counting without the spectroscopy, so it is limited to pure 222Rn measurements. In this paper, the two working modes of response mechanisms of AlphaGUARD to 220Rn were studied. This study found that, under flow mode with sampling flow rate of 1.0 L·min-1, the flow correction factor for 220Pm is 0.80; under diffusion modes, the relative sensitivity coefficient of 220Rn is independent on the 220Rn concentration and mixed 222Rn/220Rn ratio is 6.09%. (authors)

  7. Investigation of the level of radionuclide on 222Rn/220Rn and of γ dose rate in underground coal mines in Hebei province

    Objective: To investigate the level of radionuclide in underground coal mines at Tangshan district in Hebei province. Methods: The radon concentration and γ dose rate of four underground coal mines were measured with accumulative method and instant method. The activity concentration of radionuclide was measured with high pure germanium (HPGe) spectrum. Result: The accumulative measurement at four coal mines in the district show that 222Rn concentration is 50.1Bq/ m3, 220Rn is about 38.4 Bq/m3 and γ dose rate of underground coal mines is 108nGy/h; Instant measurement indicates that radon concentration is 8.7 ± 17.0 Bq/m3 and γ dose-rate is 67nGy/h at the earth surface; the arithmetic mean values of activity concentration of radionuclides for 238U, 226Ra, 232Th, 40K are 39.6, 31.3, 36.3, 26.0Bq/kg, respectively. Conclusion: Radon concentrations in underground coal mines are higher than that in the open environment. Contents of radionuclide of coal are all apparent lower than that of average of the whole counter. The normalized collective dose is 4.67 man·mSv (Mt)-1. (authors)

  8. Field measuring of radon exhalation rate from the soil by CR-39 detector

    As known, the soil under a building is contributing to overall volume activities of radon indoor. As numerous data are show, the actual values of radon exhalation rate (RER) of the same soil under laboratory and field conditions are different in tens and sometimes-even hundreds of times. Because in the real conditions, the values of RER depend on many factors: the underground cracks and voids; temperature and pressure gradients; humidity, porosity and density of the soils. These destabilizing factors of the nature an increasing of convection distances of gases of the 222Rn and 220Rn in medium of air. The paper filters that used in measuring chambers are passed both particles; radon and thoron. Visual determination of energy of α-particles by the shape of the tracks is very difficult. In order to determine the real value of 222Rn, it is necessary to take into contribution of 220Rn in total number of tracks or stop the entrance of 220Rn into the chamber using a special filter that transmits 222Rn only. However, because of the absence of such filters, we prefer to use another method, delaying of the short-lived 220Rn in the chamber air, creating impeding barrier against it. The aim of this work was the build-up two-chamber registrar with two detectors of CR-39 for field determination of exhalation rate of the 220Rn+ 222Rn and 222Rn from soil. The values of exhalation of the radon-222 from soils were found equal to 22.1 ± 4.8 and 16.2 ± 3.8 Bq/m2h for spring and summer seasons, respectively. The laboratory determination of the RER in same soils has shown the mean value is 0.10 ± 0.02 Bq/m2h. The values of RER in field 160-200 times more than laboratory measurements from the same soils. Such a large difference in the values of radon exhalation from the soil, suggests that environmental factors strongly influence the results of the field measurements of RER. The values of radon exhalation rate from the soils depend on the season also

  9. Nationwide indoor 222Rn and 220Rn map for India: a review

    Considering the role of radon in epidemiology, an attempt was made to make a nation-wide map of indoor 222Rn and 220Rn for India. More than 5000 measurements have been carried out in 1500 dwellings across the country comprising urban and nonurban locations. The solid state nuclear track detectors based twin cup 222Rn/220Rn discrimination dosimeters were deployed for the measurement of indoor 222Rn, 220Rn and their progeny levels. The geometric means of estimated annual inhalation dose rate due to indoor 222Rn, 220Rn and their progeny in the dwellings was 0.94 mSvy-1 (geometric standard deviation 2.5). It was observed that the major contribution to the indoor inhalation dose was due to indoor 222Rn and its progeny. However, the contribution due to indoor 220Rn and its progeny was not trivial as it was found to be about 20% of the total indoor inhalation dose rates. The indoor 222Rn levels in dwellings was significantly different depending on the nature of walls and floorings. - Highlights: → A countrywide survey on 222Rn and 220Rn levels for India was carried out in dwellings. → The regional values are obtained from the data on a few houses in that area. → Calibration factors for the measurements were derived experimentally as well as theoretically. → The 222Rn and 220Rn levels are represented on the maps.

  10. Field measurement of radon exhalation rate from the soil by CR-39 detector

    Determination technique of radon exhalation rate (RER) from soils in field measured by track detector CR-39 was developed. For this purpose, the method 'Russian dolls' (matrieshka) was created and used, consisting of three cylindrical plastic chambers and located inside each other. Entrance mouths of chambers are installed in opposite directions to make an artificial barrier up on the path of 220Rn. Field measurements of the RER from soils were within 16.4-22.1 Bq/m2h, that are 160 and 220 times more than laboratory measurement. The RER values from soils as laboratory and field measurements have been compared with the data of other authors. (author)

  11. Thoron (220Rn) in the indoor atmospheric environment

    Naturally occurring background radiation is a topic, which has evoked curiosity and concern between the scientist and layman alike in recent years due to the shift in focus of health effects due to exposure of radiation from acute high level to chronic low level. Many locations around the world have higher levels of natural background radiation due to elevated levels of primordial radio nuclides in the soil and their decay products like radon (222Rn), and thoron (220Rn) in the environment. Of late, technologically enhanced naturally occurring radioactive material has also contributed to the burden of background radiation. It has been estimated that inhalation of 222Rn, 220Rn and their short lived progenies contribute more than 54% of the total natural background radiation dose received by the general population. In the Indian context, in an earlier national survey, the external gamma radiation dose rates have been more or less well mapped using thermo luminescent dosimeters covering more than 214 locations, which has yielded a national average of 775 mGy/y. Of this, nearly 48.7% contribution of the dose rate is from 40K and the rest from the uranium (33.6%) and thorium (17.7%) series. A good database pertaining to the country wide levels of uranium, thorium and potassium in geological materials also exists. Thus, there exists a good database on the total external gamma radiation level across the country. Since the contribution from inhalation of 222Rn, 220Rn and their short lived progenies contributes more than 54% of the total background radiation dose, it was necessary to supplement the external component with inhalation component. This component is not adequately estimated for the country so far on national level. With this in mind, a national survey has been executed by this center involving a large number of universities and other allied research institutions from different parts of the country for the estimation of inhalation component of the dose rate

  12. Realization and characterization of a 220Rn source for calibration purposes

    The recent interest for measuring 220Rn activity in air and the following development of the corresponding measurement techniques require the improvement of standards for the calibration and characterization of the measurement devices. Due to the short half-life of the 220Rn, the adopted techniques for the production of 222Rn sources are not always reliable. In this paper a methodology for realizing a thoron known activity starting from a 232Th source will be presented and discussed. - Highlights: • A thoron source realized by well characterized samples containing thorium. • Methodology for measuring exhalated thoron activity by gamma ray spectrometry. • Stable on time thoron specific activity concentration in air. • Radon isotopes spectroscopy by electrostatic collection

  13. Study on 220Rn equilibrium factor in China traditional dwellings

    The spatial distribution and seasonal variation of 220Rn concentration (CTn) and its progeny concentration (Cp,Tn) in China traditional dwellings constructed with soil were studied. The results show that the spatial distribution of CTn appears a significant concentration gradient, and decreases exponentially from the distance of source (bare walls or ground), while there is a good linearity and repeatability. The seasonal variation of CTn displays maximum value in autumn and minimum value in winter. The seasonal variation of Cp,Tn comparing with CTn and Cp,Rn is similar, and its spatial variation can be ignored. Therefore, fixing the distance distance of 220Rn form source, there is a definite relationship between CTn and Cp,Tn. 220Rn equilibrium factors FTn respectively are 0.003±0.001 and 0.017±0.014 at the distances of 2.5 cm and 20 cm from wall. The Cp,Tn results of actual measurement in traditional houses are in good agreement with the calculated values by using FTn. The measurement to 220Rn gas is more easily achieved comparing with 220Rn progenies. The introduction of FTn provides a simple and reliable method for assessment of 220Rn exposure. (authors)

  14. Indoor 222Rn and 220Rn variations as an evidence for Boyle's law

    The 222Rn and 220Rn levels were measured for Bangalore Metropolitan, India was focused on various types of houses with respect to ventilation characteristics. Dimension of room was taken into account to correlate the air rate the virtue of number of windows and ventilation openings. Integrated and long-term measurements of radon were carried out in the dwellings using twin cup dosimeters with Solid State Nuclear Track Detector. Result shows that the concentration exponentially with the increase in room volume. (author)

  15. Indoor 222Rn and 220Rn concentrations and doses in Bangalore, India

    222Rn and 220Rn levels have been measured using passive detector technique by employing time integrated solid-state nuclear track detector-based dosemeters in various types of houses at 10 different locations in and around Bangalore Metropolitan, India. The measured geometric mean concentration values of 222Rn and 220Rn levels in 200 dwellings of different types of construction were found to be 32.2±1.6 and 21.4±1.0 Bq m-3, respectively. The dose rate received by the population of Bangalore ranged between 0.2 and 3.5 mSv y-1 with an average and the geometric mean of 1.14±0.05 and 1.06 mSv y-1, respectively. Overall, the result does not show much significant radiological risk for the inhabitants and the 222Rn levels are well within the limits of global average concentration of 40 Bq m-3. However, the 220Rn levels observed were found to be higher than the global average of 10 Bq m-3. (authors)

  16. Using 220Rn to calibrate liquid noble gas detectors

    Kobayashi, M; Takeda, A; Kishimoto, K; Moriyama, S

    2016-01-01

    In this paper, we describe 220Rn calibration source that was developed for liquid noble gas detectors. The key advantage of this source is that it can provide 212Bi-212Po consecutive events, which enables us to evaluate the vertex resolution of a detector at low energy by comparing low-energy events of 212Bi and corresponding higher-energy alpha-rays from 212Po. Since 220Rn is a noble gas, a hot metal getter can be used when introduced using xenon as the carrier gas. In addition, no long-life radioactive isotopes are left behind in the detector after the calibration is complete; this has clear advantage over the use of 222Rn which leaves long- life radioactivity, i.e., 210Pb. Using a small liquid xenon test chamber, we developed a system to introduce 220Rn via the xenon carrier gas; we demonstrated the successful introduction of 6 times 10^2 220Rn atoms in our test environment.

  17. Thoron (220Rn) in the indoor environment and work places

    Ever since studies on uranium miners established the presence of a positive risk coefficient for the occurrence of lung cancer in miners exposed to elevated levels of 222Rn and its progeny, there was a great upsurge of interest in the measurement of 222Rn in the environment. Subsequently, considerable data is being generated on the levels of 222Rn in the environment across the worlds and is being periodically reported by UNSCEAR reports. In contrast to this, data pertaining to 220Rn in indoors and workplace environment is scaree due to the general perception that its levels are negligible due to its shorter half life, and subsequently its contribution to the total inhalation dose is ignored, in the presence of other significant sources of natural radiation. This may not be true. Globally many locations have higher levels of natural background radiation due to elevated levels of primordial radio nuclides in the soil and their decay products like radon (222Rn), and thoron (220Rn) in the environment. Of late, technologically enhanced naturally occurring radioactive material has also contributed to the burden of background radiation. It is estimated that inhalation of 222Rn, 220Rn and their short lived progenies contribute more than 54% of the total natural background radiation dose received by the general population. 220Rn problem exists in industries which use thorium nitrate. Including India, lamps using thoriated gas mantles are still being used for indoor and outdoor lighting and by hawkers in rural as well as urban areas. Considering the fact that large amount of thorium nitrate is being handled by these industries, contribution to the inhalation dose of workers from 220Rn gas emanated and build up of the progeny in ambient air may also be quite significant. In this paper current status of 220Rn levels in the indoor environment and workplaces as well as in other industries where large amount of 232Th is being handled is being summarized. Methods of measurement

  18. In situ soil 222Rn and 220Rn and their relationship with meteorological parameters in tropical Northern Peninsular Malaysia

    This study focused on the relationship between soil 222Rn and 220Rn concentrations and meteorological parameters (temperature, pressure, humidity, and terrestrial gamma radiation) in Northern Peninsular Malaysia. Measurements of in situ soil 222Rn and 220Rn concentrations were performed in surface air and at a sampling depth of 50 cm using two active techniques: RAD7 radon detector and radon continuous monitor (Sun Nuclear Corporation). The surface air 222Rn concentration ranged from 6 Bq m−3 to 79 Bq m−3, whereas at the depth of 50 cm, the 222Rn and 220Rn concentrations varied from 133 Bq m−3 to 143,059 Bq m−3 and from 55 Bq m−3 to 403 Bq m−3, respectively. The gamma dose rate (DR) in air was measured using a GR-135 spectrometer (Exploranium). The dose rate varied from 80 nGy h−1 to 258 nGy h−1. The 222Rn concentration in the soil (143 kBq m−3) was high considering that the concentration in typical soil samples is only 40 kBq m−3. The 222Rn concentration in surface air varied within the recommended activity values prescribed by the United States Environmental Protection Agency and the International Commission on Radiological Protection. Weak positive and negative correlations were observed between the (222Rn and 220Rn) concentrations and the meteorological parameters. - Highlights: • DR varies (80–258 nGy h−1), no correlation between acidity and radon concentration. • 222Rn in soil (143 kBq m−3) high considering than in typical soil 40 kBq m−3. • 222Rn in surface air varied within EPA and ICRP. • All sites exhibited larger DR compared with the world of 84 nGy h−1 except for two sites. • A statistically significant correlation between 222Rns–220Rn

  19. Radon exhalation rates of some granites used in Serbia

    Nikolić Mladen D.

    2015-01-01

    Full Text Available In order to address concern about radon exhalation in building material, radon exhalation rate was determined for different granites available on Serbian market. Radon exhalation rate, along with mass exhalation rate and effective radium content were determined by closed chamber method and active continuous radon measurement technique. For this research, special chambers were made and tested for back diffusion and leakage, and the radon concentrations measured were included in the calculation of radon exhalation. The radon exhalation rate ranged from 0.161 Bq/m2h to 0.576 Bq/m2h, the mass exhalation rate from 0.167 Bq/kgh to 0.678 Bq/kgh, while the effective radium content was found to be from 12.37 Bq/kg to 50.23 Bq/kg. The results indicate that the granites used in Serbia have a low level of radon exhalation.

  20. Precursory Subsurface 222Rn and 220Rn Degassing Signatures of the 2004 Seismic Crisis at Tenerife, Canary Islands

    Pérez, Nemesio M.; Hernández, Pedro A.; Padrón, Eleazar; Melián, Gladys; Marrero, Rayco; Padilla, Germán; Barrancos, José; Nolasco, Dácil

    2007-12-01

    Precursory geochemical signatures of radon degassing in the subsurface of the Tenerife Island were observed several months prior to the recent 2004 seismic-volcanic crisis. These premonitory signatures were detected by means of a continuous monitoring of 222Rn and 220Rn activity from a bubbling CO2-rich gas spot located at 2.850 m depth inside a horizontal gallery for groundwater exploitation at Tenerife. Multivariate Regression Analysis (MRA) on time series of the radon activity was applied to eliminate the radon activity fluctuation due to external variables such as barometric pressure, temperature and relative humidity as well as power supply. Material Failure Forecast Method (FFM) was successfully applied to forecast the anomalous seismicity registered in Tenerife Island in 2004. The changes in the 222Rn/220Rn ratio observed after the period of anomalous seismicity might suggest a higher gas flow rate and/or changes in the vertical permeability induced by seismic activity.

  1. Inhalation exposures due to radon and thoron (222Rn and 220Rn): Do they differ in high and normal background radiation areas in India?

    In India, High Background Radiation Areas (HBRAs) due to enhanced levels of naturally occurring radionuclides in soil (thorium and, to a lesser extent, uranium), are located along some parts of the coastal tracts viz. the coastal belt of Kerala, Tamilnadu and Odisha. It is conjectured that these deposits will result in higher emissions of radon isotopes (222Rn and 220Rn) and their daughter products as compared to Normal Background Radiation Areas (NBRAs). While the annual external dose rates contributed by gamma radiations in these areas are about 5–10 times higher, the extent of increase in the inhalation dose rates attributable to 222Rn and 220Rn and their decay products is not well quantified. Towards this, systematic indoor surveys were conducted wherein simultaneous measurements of time integrated 222Rn and 220Rn gas and their decay product concentrations was carried out in around 800 houses in the HBRAs of Kerala and Odisha to estimate the inhalation doses. All gas measurements were carried out using pin-hole cup dosimeters while the progeny measurements were with samplers and systems based on the Direct radon/thoron Progeny sensors (DRPS/DTPS). To corroborate these passive measurements of decay products concentrations, active sampling was also carried out in a few houses. The results of the surveys provide a strong evidence to conclude that the inhalation doses due to 222Rn and 220Rn gas and their decay products in these HBRAs are in the same range as observed in the NBRAs in India. - Highlights: • Measurements of 222Rn, 220Rn and their progeny in indoors of HBRAs of India. • DTPS/DRPS deposition sensors were used for measurement progeny of 222Rn and 220Rn. • Inhalation doses were in HBRAs were comparable with those in NBRAs

  2. A study of indoor 220Rn and 222Rn decay product concentrations in the UK

    In order to gain a better understanding of the risk of human exposure to 220Rn indoors, measurements of Rn decay products have been performed in a number of houses in England. The study focused mainly on areas where above-average indoor 220Rn concentrations were to be expected because of geological or other factors. Thoron (220Rn) in room air comes mainly from the building materials, with an additional contribution from soil gas; therefore, 220Rn concentrations were examined in relation to building materials as well as location. Measurements were carried out in 23 houses. The mean equilibrium equivalent 220Rn (EET) concentration found was 0.39 Bq m-3 and the mean equilibrium equivalent 222Rn (EER) concentration was 17.8 Bq m-3. The 220Rn concentration values and EET/EER ratios found in this investigation correspond well with other published results. Values imply that the 220Rn concentrations in English dwellings are a far less important problem than 220Rn concentrations. (authors)

  3. 222Rn + 220Rn monitoring by alpha spectrometry

    Controlled 222Rn + 220Rn mixed atmospheres have been realised introducing calibrated sources in a stainless steel chamber. An electrostatic alpha monitor internal to the chamber has been used for an accurate discrimination of alpha peaks due to the products of the two isotopes. In the chamber, different specific activities are achieved in order to test the response of the internal reference instrument and to evaluate the possible interferences due to contemporary presence of both radon isotopes. Results show that: (i) the atmospheres are very stable, (ii) the monitor is adequate for their control because the various alpha lines are well evaluated and (iii) using TyvekR filter, the efficiency of monitor is stable and constant vs. activity. (authors)

  4. Inhalation exposures due to radon and thoron ((222)Rn and (220)Rn): Do they differ in high and normal background radiation areas in India?

    Mishra, Rosaline; Sapra, B K; Prajith, R; Rout, R P; Jalaluddin, S; Mayya, Y S

    2015-09-01

    In India, High Background Radiation Areas (HBRAs) due to enhanced levels of naturally occurring radionuclides in soil (thorium and, to a lesser extent, uranium), are located along some parts of the coastal tracts viz. the coastal belt of Kerala, Tamilnadu and Odisha. It is conjectured that these deposits will result in higher emissions of radon isotopes ((222)Rn and (220)Rn) and their daughter products as compared to Normal Background Radiation Areas (NBRAs). While the annual external dose rates contributed by gamma radiations in these areas are about 5-10 times higher, the extent of increase in the inhalation dose rates attributable to (222)Rn and (220)Rn and their decay products is not well quantified. Towards this, systematic indoor surveys were conducted wherein simultaneous measurements of time integrated (222)Rn and (220)Rn gas and their decay product concentrations was carried out in around 800 houses in the HBRAs of Kerala and Odisha to estimate the inhalation doses. All gas measurements were carried out using pin-hole cup dosimeters while the progeny measurements were with samplers and systems based on the Direct radon/thoron Progeny sensors (DRPS/DTPS). To corroborate these passive measurements of decay products concentrations, active sampling was also carried out in a few houses. The results of the surveys provide a strong evidence to conclude that the inhalation doses due to (222)Rn and (220)Rn gas and their decay products in these HBRAs are in the same range as observed in the NBRAs in India. PMID:26065929

  5. Research on measurement method of 220Rn progeny aerosol size distribution

    The method for measuring 220Rn progeny aerosol activity particle size distributions was introduced through ELPI system, α spectroscopy and the energy discrimination method. The different particle sizes of the 220Rn progeny aerosols were collected and the activity size distributions in the 220Rn laboratory of the University of South China were measured by this method. The experiment results show that the activity median aerodynamic diameter (AMAD) of ThB aerosol is 237 nm, and that of ThC is 245 nm. The simple and quick method can be used to monitor the particle size distributions of 220Rn progeny aerosol in real time, the aerosol activity size distributions of ThB and ThC can be obtained by this method at the same time, and the measurement accuracy of the energy spectrum is higher than that of custom method. (authors)

  6. Thoron (220Rn) progeny reduction by an air cleaner of the polarized media filter type

    The effect of an air cleaner on 220Rn progeny atmospheres has been studied in a Radon/Thoron Test Facility (RTTF) of the walk-in type. The air cleaner consists basically of a fan and a special filter material sandwiched between two metal screens, to which an electric field is applied. The filter is of the polarized media type and uses fibreglass as material. The fan and filter system are housed in a metal case. Air is drawn from the back of the case by means of the fan and forced through the 'electrical' filter where removal of the 220Rn progeny occurs. Radon-220 progeny 'depleted' air is discharged at the top of the device. Tests were conducted in 220Rn/220Rn progeny atmospheres when the air cleaner was operating, and when it was turned off. Very pronounced effects were observed during the operation of the device, namely: a dramatic decrease in the 220Rn progeny concentrations and the total aerosol concentration, as well as a large increase in the 220Rn progeny unattached fractions and the plate-out of these radionuclides on the walls of the RTTF. The air cleaner has potential in industrial applications, which should be explored. (orig.)

  7. 222Rn and 220Rn concentrations in soil gas of Karkonosze-Izera Block (Sudetes, Poland)

    Soil gas 222Rn and 220Rn concentrations were measured at 18 locations in the Karkonosze-Izera Block area in southwestern Poland. Measurements were carried out in surface air and at sampling depths of 10, 40 and 80 cm. Surface air 222Rn concentrations ranged from 4 to 2160 Bq m-3 and 220Rn ranged from 4 to 228 Bq m-3. The concentrations for 10 and 40 cm varied from 142 Bq m-3 to 801 kBq m-3 and 102 Bq m-3 to 64 kBq m-3 for 222Rn and 220Rn, respectively. At 80 cm 222Rn concentrations ranged from 94 Bq m-3 to >1 MBq m-3. The 220Rn concentrations at 80 cm varied from 45 Bq m-3 to 48 kBq m-3. The concentration versus depth profiles for 222Rn differed for soils developed on fault zones, uranium deposits or both. Atmospheric air temperature and soil gas 222Rn and 220Rn were negatively correlated. At sampling sites with steep slopes, 220Rn concentrations decreased with depth

  8. 222Rn, 220Rn and their progeny concentrations in offices in Hong Kong

    An active sampling system using charcoal canisters and an HPGe γ-spectrometer was employed to survey 222Rn and 220Rn concentrations in 65 offices in Hong Kong, and a traditional method was used to record simultaneously the potential α-energy concentrations (PAEC) of 222Rn and 220Rn progeny at the same sites. The mean values of gas concentration, PAEC and equilibrium factor for 222Rn were 48±32 Bq m-3, 5.2±5.1 mWL and 0.38±0.13, respectively, and the corresponding values for 220Rn were 14±7 Bq m-3, 2.7±2.1 mWL and 0.050±0.016. These values were in general higher than those in dwellings in Hong Kong, which was due to the poorer fresh air exchange in offices. Factors affecting the concentrations of 222Rn, 220Rn and their progeny were also studied. The type of air conditioners and the indoor and outdoor temperature difference show some effects on 222Rn, 220Rn and progeny concentrations, while rainfall and relative humidity affect only the progeny concentrations

  9. Peak tailing correction in measurement of 222Rn/220Rn activity concentration with α spectrum method

    α spectrum method is one of the most important methods in measurement of 222Rn/220Rn concentration in environment. However, the peak tailing from high energy particles is an obstacle for accurate measurement. To improve the accuracy of measurement, study on the mechanism and effect of the tailing were carried out, and calibrating experiments on peak tailing correction factors were also realized using ERS-2 monitor. The peak tailing correction factors and calibration factors of 222Rn and 220Rn were measured by experiment and their accuracy were also tested. It is suggested that during calibrating α spectrum monitor of 222Rn/220Rn activity concentration, the peak tailing correction and calibration factors should be recalibrated if necessary. (authors)

  10. CFD based simulation of thoron ((220)Rn) concentration in a delay chamber for mitigation application.

    Agarwal, T K; Sahoo, B K; Gaware, J J; Joshi, M; Sapra, B K

    2014-10-01

    The release of (220)Rn gas (conventionally referred to as thoron) is an issue of concern from the radiological point of view for occupational environments pertaining to the thorium fuel cycle. Studies for understanding its release and developing systems to control it are crucial for exposure control research. A thorough study of the "Delay Volume Technique" for mitigation of (220)Rn has been carried out. Experiments have been carried out with (220)Rn source and associated measurement system in a cubical chamber (delay chamber) of 0.5 m(3) volume. For different flow conditions and inlet-outlet positions, (220)Rn transmission factor has been obtained. Computational Fluid Dynamics (CFD) technique has been employed for these experimental conditions and the simulated transmission factors have been compared. The results show that the flow and the position of the inlet and outlet play an imperative role in the transportation, mixing and subsequent mitigation of thoron inside the chamber. Predictive capability of CFD technique for such delay volume experiments has been validated in this work. A comparison has been made with uniform mixing model and it is found that the results of simulation differ appreciably from that of uniform mixing model at the tested flow regime. PMID:24860913

  11. Measurement of the indoor and outdoor 220Rn (thoron) equilibrium factor: Application to lung dose

    A miniature four-chamber alpha track detector was developed that measures both 222Rn (radon) and 220Rn (thoron), in duplicate. Using this detector and the previous long-term measurements of the 220Rn decay products 212Pb, and 212Bi, an equilibrium factor, Feq, is derived for both outdoor and indoor 220Rn environments (0.004+0.001 outdoors and 0.04+0.01 indoors). The lung airway dose can then be calculated from a dose factor from UNSCEAR that requires the equilibrium equivalent thoron concentration (EEC), i.e. the product of Feq and the 220Rn gas concentration. The lung dose from thoron in domestic or occupational surveys is often overlooked. The values of Feq for thoron in several published studies are in general agreement with the values reported here. Thus, a long-term alpha track measurement of thoron multiplied by an appropriate indoor or outdoor equilibrium factor yields the EEC, which can be used to assess bronchial lung dose. (authors)

  12. Measurements of 222Rn and 220Rn with a Large Size Collector of Radon Progeny

    Wu Qifan; Jia Wenyi; Fang Fang; Wang Jun; Cheng Jianping; Liu Guilin; Zhu Li

    2003-01-01

    Radon concentrations in high background radiation areas in the south are higher than those of others in China, especially 220Rn concentration is significantly high. Therefore, measurements of 222Rn and 220 Rn concentrations should be carried out there. This paper introduces a large size collector of radon progeny and its applications. The collector is a sheet of polyvinyl chloride fiber with electrostatics of (-500 V) - ( -700 V). Its size (60 mm in diameter) is larger than those of others (26 mm in diameter) that work with the same principle. The collector is more effective to adsorb radon progeny than most of others. The equipment of ZnS(Ag) Scintillation Counting System is available for large size collectors to detect radon progeny. Therefore, its sensitivity of measurement is higher than that of others.According to the different half lives of radon progeny, and based on both theory and experiments, a formula for discrimination and calculation of 222 Rn and 220Rn concentrations is deduced. The 222Rn and 220Rn concentrations were surveyed with electrostatic collectors of radon progeny on the campus of com-mercial school and some other areas in Hainan, southern China. Neither 222Rn nor 220Rn concentration was found significantly high. However, several faults underground were delineated. The collector is also used to study radon transportation. Results indicate that radon changes regularly with date when it has transported for a certain distance. Velocities of radon migration in the four media are quite different.Radon migrates more quickly in vertical tube than in the horizontal tube.

  13. Measurements of 222Rn and220Rn with a large size collector of radon progeny

    People have paid more attention to radon since 1980s. Radon concentrations in high background radiation areas in the south are higher than others in China, especially 220 Rn concentration is significantly high. Therefore, measurement of 222 Rn and 220 Rn concentration should be carried out there. I will introduce a large size collector of radon progeny and its applications in this paper. The collector is a sheet of polyvinyl chloride fibre with electrostatics of -500V ∼ -700V. Its size (60mm in diameter) is larger than others (26mm in diameter) that work as the same principle. The collector is more effective to adsorb radon progeny than most of others. The equipment of ZnS(Ag) Scintillation Counting System is available for large size collectors to detect radon progeny. Therefore its sensitivity of measurement is high than others. According to the different half life of radon progeny and based on both theory and experiment, a formula for discrimination and calculation of 222 Rn and 220 Rn concentrations was deduced. The 222 Rn and 220 Rn concentrations were surveyed with electrostatic collectors of radon progeny on the campus of commercial school and some other areas in Hainan, southern China. Neither 222 Rn nor 220 Rn concentrations were found significant high. However several faults underground were delineated. The collector is also used to study radon transportation. Results indicate that radon changes regularly with date when it has transported for a certain distance. Velocities of radon migration in the four media are quite different. Radon migrates more quickly in vertical tube than in the horizontal tube

  14. The Distribution Characteristics of 222Rn and 220Rn Concentrations in Soil Gas In Zhongshan City, Guangdong Province, China

    A mapping survey of 222Rn and 220Rn concentrations in soil gas was conducted for the first time using a RAD7 portable radon monitor at 67 locations across an area of 1800 km2 in Zhongshan City (ZSC), Guangdong Province. It was found that 222Rn concentrations increased with increasing depth, whereas 220Rn concentrations were almost unchanged at different depths. The sites with high 222Rn values were located mainly in granite outcrops, while those with low values were located in a sedimentary region. The distribution patterns of 220Rn coincide with the patterns of activity concentration of 232Th in soil. (author)

  15. Revision for measuring radon exhalation rate in open loop

    Tan, Y.; Xiao, D.; Yuan, H.; Tang, Q.; Liu, X.

    2013-01-01

    We propose a novel method for quickly measuring the radon exhalation rate in open loop. We first obtain the temporal variation of radon concentration in the internal cell of the RAD7 by analyzing the work principle of RAD7. We then obtain the temporal variation of radon concentration in the ventilation-type accumulation chamber when the effects of leakage and back diffusion are neglected. This method uses the measured value before the radon concentration in the ventilation-type accumulation chamber reaches a steady state. The diameter of the air input tube to the ventilation-type accumulation is large enough to keep the differential pressure in the accumulation chamber and outdoors negligible. Short cycle time and large flow rate will be appropriate for reducing measurement error. Several radon exhalation rate measurements of the medium surface have been performed in the Radon Laboratory of the University of South China. The radon exhalation rates obtained by verification experiments are in good agreement with the reference value. This method can be applied to develop and improve the instruments for measuring radon exhalation rate.

  16. Revision for measuring radon exhalation rate in open loop

    We propose a novel method for quickly measuring the radon exhalation rate in open loop. We first obtain the temporal variation of radon concentration in the internal cell of the RAD7 by analyzing the work principle of RAD7. We then obtain the temporal variation of radon concentration in the ventilation-type accumulation chamber when the effects of leakage and back diffusion are neglected. This method uses the measured value before the radon concentration in the ventilation-type accumulation chamber reaches a steady state. The diameter of the air input tube to the ventilation-type accumulation is large enough to keep the differential pressure in the accumulation chamber and outdoors negligible. Short cycle time and large flow rate will be appropriate for reducing measurement error. Several radon exhalation rate measurements of the medium surface have been performed in the Radon Laboratory of the University of South China. The radon exhalation rates obtained by verification experiments are in good agreement with the reference value. This method can be applied to develop and improve the instruments for measuring radon exhalation rate.

  17. Radon exhalation rates from some soil samples of Kharar, Punjab

    Mehta, Vimal [Deptt of Physics, M. M. University, Mullana (Ambala)-133 207 (India); Deptt of Physics, Punjabi University, Patiala- 147 001 (India); Singh, Tejinder Pal, E-mail: tejinders03@gmail.com [Deptt of Physics, S.A. Jain (P.G.) College, Ambala City- 134 003 (India); Chauhan, R. P. [Deptt of Physics, National Institute of Technology, Kurukshetra- 136 119 (India); Mudahar, G. S. [Deptt of Physics, Punjabi University, Patiala- 147 001 (India)

    2015-08-28

    Radon and its progeny are major contributors in the radiation dose received by general population of the world. Because radon is a noble gas, a large portion of it is free to migrate away from radium. The primary sources of radon in the houses are soils and rocks source emanations, emanation from building materials, and entry of radon into a structure from outdoor air. Keeping this in mind the study of radon exhalation rate from some soil samples of the Kharar, Punjab has been carried out using Can Technique. The equilibrium radon concentration in various soil samples of Kharar area of district Mohali varied from 12.7 Bqm{sup −3} to 82.9 Bqm{sup −3} with an average of 37.5 ± 27.0 Bqm{sup −3}. The radon mass exhalation rates from the soil samples varied from 0.45 to 2.9 mBq/kg/h with an average of 1.4 ± 0.9 mBq/kg/h and radon surface exhalation rates varied from 10.4 to 67.2 mBq/m{sup 2}/h with an average of 30.6 ± 21.8 mBq/m{sup 2}/h. The radon mass and surface exhalation rates of the soil samples of Kharar, Punjab were lower than that of the world wide average.

  18. Relationship of 220Rn and 222Rn progeny levels in Canadian underground U mines

    Radon-222 and 220Rn progeny are found in some Canadian underground U mines. Because both can contribute to lung dose, their experimental determinations are important. The relationship between 222Rn progeny Working Level [WL(Rn)] and 220Rn progeny Working Level [WL(Tn)] has been investigated in U mines. Experimental measurements extended from 1981 to 1986 and consisted of about 700 measurements of each WL(Rn) and WL(Tn). The data were analyzed by standard linear and power-function regression analysis. A power-function relationship between WL(Rn) and WL(Tn) seemed to fit the experimental data best. The relationship obtained permits the calculation of WL(Tn) from experimental values of WL(Rn). The relationship is useful for lung-dose-calculation purposes and in mine-ventilation-engineering calculations

  19. GUM approach to uncertainty estimations for online 220Rn concentration measurements using Lucas scintillation cell

    It is now widely recognized that, when all of the known or suspected components of errors have been evaluated and corrected, there still remains an uncertainty, that is, a doubt about how well the result of the measurement represents the value of the quantity being measured. Evaluation of measurement data - Guide to the expression of Uncertainty in Measurement (GUM) is a guidance document, the purpose of which is to promote full information on how uncertainty statements are arrived at and to provide a basis for the international comparison of measurement results. In this paper, uncertainty estimations following GUM guidelines have been made for the measured values of online thoron concentrations using Lucas scintillation cell to prove that the correction for disequilibrium between 220Rn and 216Po is significant in online 220Rn measurements

  20. A 220Rn source for the calibration of low-background experiments

    Lang, R. F.; Brown, A.; Brown, E.; Cervantes, M.; Macmullin, S.; Masson, D.; Schreiner, J.; Simgen, H.

    2016-04-01

    We characterize two 40 kBq sources of electrodeposited 228Th for use in low-background experiments. The sources efficiently emanate 220Rn, a noble gas that can diffuse in a detector volume. 220Rn and its daughter isotopes produce α-, β-, and γ-radiation, which may used to calibrate a variety of detector responses and features, before decaying completely in only a few days. We perform various tests to place limits on the release of other long-lived isotopes. In particular, we find an emanation of detectors employing liquid noble elements such as argon and xenon. With the source mounted in a noble gas system, we demonstrate that filters are highly efficient in reducing the activity of these longer-lived isotopes further. We thus confirm the suitability of these sources even for use in next-generation experiments, such as XENON1T/XENONnT, LZ, and nEXO.

  1. Radon activity and exhalation rates in Indian fly ash samples

    Fly ash is the by-product of burnt coal which is naturally occurring radioactive material (NORM). Because of human activity and its use in manufacturing of bricks, sheets, cement, land filling etc. may present a radiation hazard to people and the environment. Thus, it is very important to carry out radioactivity measurements in fly ash from the health and hygiene point of view. In the present study, the activity concentrations of 238U, 232Th and 40K have been varied from 99 ± 2 to 203 ±4 Bq/kg, 145 ± 2 to 288 ± 4 Bq/kg, and 355 ± 5 to 516 ± 6 Bq/kg, respectively in various fly ash samples. The radium equivalent activity was varied from 317 to 614 Bq/kg, radon activity varied from 214 to 590 Bq/m3, radon exhalation rate varied from 7.8 to 21.6 inBqkg-1h-1 for mass exhalation rate and from 138 to 381 mBqm2h-1 for surface exhalation rate in the fly ash samples used in the present investigation. The absorbed dose varied from 143 to 277 nGyh-1, the indoor annual effective dose varied from 0.70 to 1.36 mSv and the outdoor annual effective dose varied from 0.17 to 0.34 mSv. In all the samples, the activity concentration of 238U, 232Th and 40K was found to be below the permissible levels. A strong positive correlation has been observed between uranium concentration, radon activity and radon exhalation rate. (author)

  2. Radon exhalation rate of soil in Chamaraja Nagar area, India

    Human beings are continuously exposed to ionizing radiation from natural sources. The main contributors to natural radiation are high-energy cosmic radiation and radioactive nuclides that originates in the earths crust. 222Rn a decay product of 226Ra in the naturally occurring 238U series is a radioactive inert gas and constitutes about half the radiation dose received by general population. The amount of radon that escapes from the earth depends mainly on the amounts of radium in the ground along with other factors, like the type of the soil cover, porosity, etc. The majority of radiation exposure of the population comes from radon an á-radioactive, inert gas. Radon produces the main natural radiation exposure for human beings and has been recognized as carcinogenic gas. In the present study Radon exhalation rate and Radium concentration in soil and rock samples around Chamaraja Nagar area of Karnataka state, India, are measured by SSNTD method, using can technique and LR-115 type II detectors. The radium activity in rock sample varies from 2.9 to 39.5 Bqkg-1. Mass and Surface exhalation rate of radon in rock samples varies from 8.1 to 119.7 mBqkg-1h-1 and 454.7 to 1787.3 mBqm-2h-1 respectively. Radium concentration in soil samples has been found to vary from 3.6 to 34.1 Bqkg-1 with an average value of 16.5 Bqkg-1. The surface exhalation rate of radon 142 to 1377.3 mBqm-2h-1. The mass exhalation rate of radon in soil samples has been found to vary from 10 to 31.4 mBqkg-1h-1, with an average value of 19.3 mBqkg-1h-1 and standard deviation of 7.6. (author)

  3. Effect of 220Rn gas concentration distribution on its transmission from a delay chamber: evolving a CFD-based uniformity index

    220Rn mitigation can be achieved by delay chamber technique, which relies on the advantage of its short half-life. However, flow rate as well as inlet-outlet position for the delay chamber can have a significant impact on 220Rn concentration distribution patterns and hence transmission factor. In the present study, computational fluid dynamics simulations to estimate the concentration distribution has been carried out in a chamber of 0.5 m3 for the combination of six different inlet-outlet positions and five different flow rates. Subsequently, the transmission factor (TF) for the chamber was evaluated and found to be highly dependent on the flow rate and inlet-outlet positions. For ease of scale up, the dependency of TF on the flow rate and the inlet-outlet positions is best summarised by relative transmission factor (RTF), which is the ratio of the TFs for the case of inlet and outlet on different faces to that on the same face. (authors)

  4. 222Rn, 220Rn and other dissolved gases in mineral waters of southeast Brazil

    This paper describes the natural radioactivity due to 222Rn and 220Rn in mineral waters occurring at São Paulo and Minas Gerais states, Brazil, that are extensively used for drinking in public places, bottling and bathing purposes, among other. The measurements of these alpha-emitting radionuclides were also accompanied by the monitoring of temperature and some dissolved gases (O2, CO2 and H2S) in 75 water sources located in 14 municipalities of those states. Eight water sources yielded 220Rn activity concentration values below the detection limit of 4 mBq/L. On other hand, 222Rn activity concentration values exceeding the WHO guidance level of 100 Bq/L in drinking-water for public water supplies were found in two springs, named Villela and Dona Beja, whose discharge occurs in areas characterized by the presence of enhanced levels of natural radioelements in rocks. The obtained results were compared with the guidelines of the Brazilian Code of Mineral Waters (BCMW) that was established in 1945 and is still in force in the country. The 222Rn and 220Rn activity concentration data allowed perform dose radiation calculations based on the potential alpha energy concentration (PAEC), whose implications for health risk have been also considered in this paper. - Highlights: • First thoron data in mineral waters occurring in well-known Brazilian spas. • Integration of thoron and radon data with those of others dissolved gases in mineral waters. • Comparison of the acquired data with the guidelines of the Brazilian Code of Mineral Waters. • Comparison of the radiation dose due to radon and thoron in the mineral waters

  5. 222Rn, 220Rn Concentrations and Miner Doses in Non-Uranium Mines in China

    A preliminary survey of 222Rn and 220Rn concentrations in non-uranium mines in China was conducted in 17 different types of mines. In total, 44 mines in 12 provinces were surveyed. The results showed that among 25 metal mines (n = 147) the arithmetic mean and geometric mean concentrations were 1214 ± 2358 and 313 ± 5.5 Bq/m3 for 222Rn, respectively (range 11–19 600 Bq/m3) and 268 ± 701 and 70 ± 4.4 Bq/m3 for 220Rn, respectively (range 220Rn, respectively (range 220Rn. The average dose in coal mines was 0.75 mSv, and in non-metal mines it was 0.38 mSv. (author)

  6. Dose ratio of 222Rn to 220Rn progeny in a pit using in-suit HPGe γ spectrometry

    To probe potential α energy concentration (PAEC) ratio and dose ratio of 222Rn to 220Rn progeny in a pit, in-situ HPGe γ spectrometry was used under atmospheric ventilation and without atmospheric ventilation conditions. The measurement data was analysed using relative efficiency method and PAEC method. The measurement results show that the average PAEC ratio and dose ratio of 222Rn to 220Rn progeny under without atmospheric ventilation is 3.6 and 10.8, respectively, which is 1.2 and 3.6 in first 8 hours under atmospheric ventilation. After 14 hours atmospheric ventilation, PAEC ratio and dose ratio are 0.2 and 0.6 stably. In-situ HPGe γ spectrometry has a great space in 222Rn and 220Rn dose research in the future. (authors)

  7. Research on factors influencing radon exhalation rate on aerated concrete block

    The research was carried out on the variation of the radon exhalation rate of aerated concrete block with the water content and dimension by using the RAD7 radon monitor and the radon exhalation rate test cabin of building materials. The result indicates that the amount of the same samples has no influence on the samples' radon exhalation; if the volume of the aerated concrete block in the test cabin is unchanged and the surface area increases, the radon exhalation rate decreases, but the total of the radon exhaling from the surface of the aerated concrete block keeps constant; for the aerated concrete block, its radon exhalation rate increases with water content as logarithmic growth. (authors)

  8. Natural radioactivity and radon specific exhalation rate of zircon sands

    Righi, S.; Verita, S.; Bruzzi, L. [Bologna Univ., Centro Interdipartimentale di Ricerca per le Scienze Ambientali and Dipt. di Fisica, Ravenna (Italy); Albertazzi, A. [Italian Ceramic Center, Bologna (Italy)

    2006-07-01

    The study focuses on the radon emanation from zircon sands and their derivatives, which are widely used in many sectors of industry. In particular, the results obtained by experimental measurements on samples of zircon sands and zircon flours commonly used in Italian ceramic industries are reported. Zircon sands contain a significant concentration of natural radioactivity because Th and U may substitute zirconium in the zircon crystal lattice. The relevant routes of exposure of workers to T.E.N.O.R.M. from zircon materials are external radiation and internal exposure, either by inhalation of aerosols in dusty working conditions or by inhalation of radon in workplaces. The main objective of this investigation is to provide experimental data able to better calculate the internal exposure of workers due to radon inhalation. Zircon samples were surveyed for natural radioactivity, radon specific exhalation rate and emanation fraction. Measurements of radioactivity concentration were carried out using {gamma}-spectrometry. Methods used for determining radon consisted in determining the {sup 222}Rn activity accumulated in a vessel after a given accumulation build-up time. The average activity concentrations of {sup 238}U and {sup 232}Th in samples result about 2600 and 550 Bq kg-1, respectively; these concentrations are significantly higher than the world average noticed in soils, rocks and Earth crust. The {sup 222}Rn specific exhalation rates result very low probably due to the low porosity of the material and the consequent difficulty for radon to be released from the zircon crystal lattice. (author)

  9. Radon exhalation rates from some building construction materials using SSNTDs

    Radon appears mainly by diffusion processes from the point of origin following α- decay of 226Ra in underground soil and building materials used. in the construction of floors, walls, and ceilings. In dwellings main source of radon are soil or rock underneath, building materials and portable water supplies. The major release of radon indoors is from building construction materials used. The radon measurements on the ground can give a clue about the hidden uranium. The exposure of population to high concentrations of radon and its daughters for a long period leads to pathological effects like the respiratory functional changes and the occurrence of lung cancer. In the present investigations radon exhalation rates from some soil and other building materials like fly ash, cement and sand collected from Panchkula, Ambala, Yamunanagar, Kurukshetra, Karnal and Panipat districts of Haryana have been estimated. For the measurement of radon concentration in these samples we used α-sensitive LR-115 type II plastic track detectors. The mass and the surface exhalation rates of radon emanated from these samples have also been calculated. The aim of study is the possible health risk assessment due to emission of radiation from building construction materials. (author)

  10. Natural radioactivity and radon specific exhalation rate of zircon sands

    The study focuses on the radon emanation from zircon sands and their derivatives, which are widely used in many sectors of industry. In particular, the results obtained by experimental measurements on samples of zircon sands and zircon flours commonly used in Italian ceramic industries are reported. Zircon sands contain a significant concentration of natural radioactivity because Th and U may substitute zirconium in the zircon crystal lattice. The relevant routes of exposure of workers to T.E.N.O.R.M. from zircon materials are external radiation and internal exposure, either by inhalation of aerosols in dusty working conditions or by inhalation of radon in workplaces. The main objective of this investigation is to provide experimental data able to better calculate the internal exposure of workers due to radon inhalation. Zircon samples were surveyed for natural radioactivity, radon specific exhalation rate and emanation fraction. Measurements of radioactivity concentration were carried out using γ-spectrometry. Methods used for determining radon consisted in determining the 222Rn activity accumulated in a vessel after a given accumulation build-up time. The average activity concentrations of 238U and 232Th in samples result about 2600 and 550 Bq kg-1, respectively; these concentrations are significantly higher than the world average noticed in soils, rocks and Earth crust. The 222Rn specific exhalation rates result very low probably due to the low porosity of the material and the consequent difficulty for radon to be released from the zircon crystal lattice. (author)

  11. Thoron (220Rn)-concentration in homes: first results of a pilot project

    First measurements of thoron gas concentrations in homes show that the indoor thoron concentration is less influenced by the thoron content in soil or by convective entry processes. The indoor concentration is dominated by thoron concentrations of building materials and by the surface layer of walls and floors. Measurements in typical indoor air without additional aerosol sources yield 212Pb size distributions with a media diameter of the accumulation mode of about 200 nm. An average fraction of 13% of the activity is associated with particles of the nuclei mode with diameters d between 10 - 100 nm and about 5% of the activity was determined to be unattached (d 212Pb)/C(220Rn) of 0.05 and C(212Bi)/C(212Pb) of 0.4. (orig.)

  12. The measurement of thoron (220Rn) concentration in indoor air continuously using pylon model WLx

    The concentration of thoron (220Rn) in particular location can be higher than radon (220Rn), however, its presence is always neglected. This might be due to the difficulties in calibration and discrimination between radon and thoron. From biokinetic and dosimetric model, it has been known that the dominant contribution of thoron to the effective dose is in the lungs. UNSCEAR estimates the doses contribution of thoron and its progenies is between 5-10% of the annual dose received by the general public and the risk level is 4.4 times greater than radon and progenies. Therefore, it is necessary to study the thoron concentration in indoor air and workplaces. Radon-thoron concentration in indoor air can be determined by direct methods using Pylon Model WLx device and passive methods using Solid State Nuclear Track Detector (SSNTDs). In this research the measurement of thoron was carried out continuously using Pylon Model WLx equipment that is sensitive to radon for 24, 65, 72, 116 and 154 hours in different rooms. The measurement result showed that the mean value of thoron working level (WL) concentration obtained in room-1 was 2.53 ± 0.67 Bq/m3 with maximum and minimum of thoron concentrations were 3.37 and 2.22 Bq/m3 respectively. From the measurement in different locations, it was obtained that the largest and smallest average concentrations of thoron progenies were 0.83 ± 0.23 Bq/m3 and 0.29 ± 0.64 Bq/m3, while the maximum and minimum concentration values were 7.80 Bq/m3 and 0.01 Bq/m3 respectively. Pylon Model WLx device is not enables to be used for longer and large scale survey area concurrently, so the SSNTDs which is sensitive to the emission of alpha particles and can measure cumulative thoron concentrations is required. (author)

  13. In situ measurements of radon and thoron exhalation rates and their geological interpretation

    Radon and thoron exhalation rates from the ground were measured at 23 sites in Tokyo and nine prefectures of Japan that were selected in consideration of geological features and soil distribution. The in situ measurements were carried out with a ZnS (Ag) scintillation detector equipped with a photomultiplier and a container measuring 30 x 40 cm and 11 cm in depth. The arithmetic means of radon and thoron exhalation rates were estimated to be 7.6 ± 2.6 mBq·m-2·s-1 and 0.69 ± 0.16 Bq·m-2·s-1, respectively. The exhalation rates differed up to 37-fold for radon and 265-fold for thoron between the maximum and minimum values, respectively. A geological interpretation suggests that the regional variations of the exhalation rates were mainly controlled by the source rock of the soil distributed around the measuring site. The correlation coefficient between the exhalation rate and SiO2 content of the rocks and soils distributed around the sites were estimated to be 0.99 for radon and 0.90 for thoron, respectively. Geological information is therefore considered to be a good indicator for estimating the exhalation rate. In addition, a correlation coefficient of 0.78 was accepted between the radon and thoron exhalation rates. This is considered to be useful information for making a rough estimation of one exhalation from the other. (author)

  14. Study of effect of addition of fly ash on radon exhalation rate in cement samples

    Most of the building materials like cement and fly ash contain naturally occurring radioactive materials (NORM). Increased interest in measuring radon exhalation rate in building products is due to the concern about health hazards of NORM. This paper focuses on studying the effect of addition of fly ash on radon exhalation rate in cement samples. Ordinary Portland Cement (OPC) and coal fly ash were used for finding the exhalation rate of cement in this paper. To study the effect on exhalation rate of cement, fly ash is added in different proportions to cement samples. The measurement was conducted by CAN Technique using SSNTDs. A gradual increase has been observed in radon exhalation rate up to certain proportion and then start to decrease. (author)

  15. Studying radon exhalation rates variability from phosphogypsum piles in the SW of Spain

    López-Coto, I., E-mail: israel.lopez@dfa.uhu.es [Dpto. Física Aplicada, Facultad CC. Experimentales, University of Huelva, Campus de El Carmen s/n, 21007 Huelva (Spain); Mas, J.L. [Dpto. Física Aplicada I. Escuela Politécnica Superior, University of Sevilla, C/Virgen de Africa 7, 41012 Sevilla (Spain); Vargas, A. [Universitat Politècnica de Catalunya, Instituto de Técnicas Energéticas, Campus Sud Edificio ETSEIB, Planta 0, Pabellón C, Av. Diagonal 647, 08028 Barcelona (Spain); Bolívar, J.P. [Dpto. Física Aplicada, Facultad CC. Experimentales, University of Huelva, Campus de El Carmen s/n, 21007 Huelva (Spain)

    2014-09-15

    Highlights: • Variability of radon exhalation rates from PG piles has been studied using numerical simulation supported by experimental data. • Most relevant parameters controlling the exhalation rate are radon potential and moisture saturation. • Piling up the waste increasing the height instead of the surface allows the reduction of the exhalation rate. • A proposed cover here is expected to allow exhalation rates reductions up to 95%. - Abstract: Nearly 1.0 × 10{sup 8} tonnes of phosphogypsum were accumulated during last 50 years on a 1200 ha disposal site near Huelva town (SW of Spain). Previous measurements of exhalation rates offered very variable values, in such a way that a worst case scenario could not be established. Here, new experimental data coupled to numerical simulations show that increasing the moisture contents or the temperature reduces the exhalation rate whilst increasing the radon potential or porosity has the contrary effect. Once the relative effects are compared, it can be drawn that the most relevant parameters controlling the exhalation rate are radon potential (product of emanation factor by {sup 226}Ra concentration) and moisture saturation of PG. From wastes management point of view, it can be concluded that piling up the waste increasing the height instead of the surface allows the reduction of the exhalation rate. Furthermore, a proposed cover here is expected to allow exhalation rates reductions up to 95%. We established that the worst case scenario corresponds to a situation of extremely dry winter. Under these conditions, the radon exhalation rate (0.508 Bq m{sup −2} s{sup −1}) would be below though close to the upper limit established by U.S.E.P.A. for inactive phopsphogypsum piles (0.722 Bq m{sup −2} s{sup −1})

  16. A simple model for automatically measuring radon exhalation rate from medium surface

    A simple model to measure radon exhalation rate from medium surface is developed in this paper. This model is based on a combination of the “accumulation chamber” technique and a radon monitor. The radon monitor is used to perform measurement of radon concentration evolution inside the accumulation chamber, and radon exhalation rate is evaluated via nonlinear least-square fitting of the measured data. If the flow rate of the pump is high enough, radon concentration in the detector's internal cell becomes to be equal to that in the accumulation chamber quickly, and the simple model for measuring the radon exhalation rate can be generated analytically. Generally, the pump flow rate of radon monitor is low, not satisfying the condition. We find other sufficient conditions of this simplified model. On these conditions, the radon exhalation rate can be calculated accurately through this model even the flow rate of the pump is not so high. This method can be applied to develop and improve the instruments for measuring the radon exhalation rate. - Highlights: • We present a novel simple model for measuring radon exhalation rate based on the complex model we published before. • The algorithm based on the simple model is developed. • The radon exhalation rate can be obtained by nonlinear least squares fitting. • The applicable condition of this simple model is obtained

  17. Investigation and analysis on seasonal variations of indoor 222Rn and 220Rn concentration in Longdong district, Gansu Province

    Objective: To study the seasonal variation of indoor 222Rn and 220Rn concentrations in Longdong district, Gansu Province. Methods: A total of 44 houses from 5 different types of raw soil architectures and 5 ordinary brick houses from a typical area were selected in Longdong district, Gansu Province in China. The LD-P discriminative 222Rn and 220Rn detectors were used to measure the indoor concentrations of 222Rn and 220Rn during four seasons in one year. Results: The indoor concentrations of 222Rn showed a significant seasonal variation,which varied with different types of houses. 222Rn concentrations of ordinary brick houses, soil brick houses and the cave dwellings were higher in winter and autumn and lower in summer. The average concentrations of 222Rn were 55.3-90.3 Bq/m3 in winter,36.4-65.7 Bq/m3 in spring, 35.6-63.9 Bq/m3 in summer, and 60.7-87.2 Bq/m3 in autumn. For cave dwellings,open-cut cave dwellings and the underground cave dwellings, 222Rn concentrations were higher in summer and autumn, and lower in winter and spring. The average concentrations of 222Rn ranged from 139-184 Bq/m3 in winter,135-199 Bq/m3 in spring, 179-252 Bq/m3 in summer,172-242 Bq/m3 in autumn. The seasonal variation of indoor 220Rn was basically consistent in six types of houses, and lower in winter and spring and highest in autumn. The average concentrations of 220Rn ranged from 43.4-64.3 Bq/m3 in winter, 60.6-537 Bq/m3 in spring, 77.7-792 Bq/m3 in summer, 63.2-1077 Bq/m3 in autumn. The indoor concentrations of 222Rn and 220Rn were different among different types of houses, and they were generally higher in type of raw soft architectures than in that of ordinary brick houses. Conclusions: 222Rn concentrations indoors showed a significant seasonal variation and varied with different types of houses. (authors)

  18. Do nuclei go pear-shaped? Coulomb excitation of 220Rn and 224Ra at REX-ISOLDE (CERN

    Scheck M.

    2015-01-01

    Full Text Available The IS475 collaboration conducted Coulomb-excitation experiments with post-accelerated radioactive 220Rn and 224Ra beams at the REX-ISOLDE facility. The beam particles (Ebeam: 2.83 MeV/u were Coulomb excited using 60Ni, 114Cd, and 120Sn scattering targets. De-excitation γ-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured γ-ray yields. The extracted ‹3−||E3||0+› matrix element allows for the conclusion that, while 220Rn represents an octupole vibrational system, 224Ra has already substantial octupole correlations in its ground state. This finding has implications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei.

  19. Effect of moisture on radon exhalation rate of the building material bricks

    In the paper, The moisture of building material bricks was controlled by the saturation solution of inorganic salt which were deposited in a obturator. The activated charcoal method was used to compare the influence of radon exhalation rate of building material bricks on different moistures condition. From the result, it can be found that with the increasing of mositure, the radon exhalation rate is increasing at first and then discreasing, when the mositure is about 4%, and the highest radon exhalation rate is 32.31 ± 2.84mBq. m-2.s-1. (authors)

  20. Surface-deposition and Distribution of the Radon (222Rn and 220Rn) Decay Products Indoors

    Espinosa, G.; Tommasino, Luigi

    The exposure to radon (222Rn and 220Rn) decay products is of great concern both in dwellings and workplaces. The model to estimate the lung dose refers to the deposition mechanisms and particle sizes. Unfortunately, most of the dose data available are based on the measurement of radon concentration and the concentration of radon decay products. These combined measurements are widely used in spite of the fact that accurate dose assessments require information on the particle deposition mechanisms and the spatial distribution of radon decay products indoors. Most of the airborne particles and/or radon decay products are deposited onto indoor surfaces, which deposition makes the radon decay products unavailable for inhalation. These deposition processes, if properly known, could be successfully exploited to reduce the exposure to radon decay products. In spite of the importance of the surface deposition of the radon decay products, both for the correct evaluation of the dose and for reducing the exposure, little or no efforts have been made to investigate these deposition processes. Recently, two parallel investigations have been carried out in Rome and at Universidad Nacional Autónoma de México (UNAM) in Mexico City respectively, which address the issue of the surface-deposited radon decay products. Even though these investigations have been carried independently, they complement one another. It is with these considerations in mind that it was decided to report both investigations in the same paper.

  1. Estimation of 222Rn, 220Rn and their progeny concentration using pin-hole cup dosimeters and deposition based progeny sensors

    Radon (220Rn) and Thoron (220Rn) progeny concentrations contribute to the natural radiation dose to general public. Due to the fact that the inhalation doses due to 222Rn and 220Rn are contributed predominantly by their decay products, development of passive techniques for monitoring the decay products directly assumes considerable significance. The concentrations of progenies are determined through Equivalent Equilibrium Concentrations of 222Rn as well as 220Rn (EERC and EETC) respectively. EERC and EETC are measured by deposition based Direct Progeny Sensors (DRPS, DTPS) in bare modes. Direct Thoron Progeny Sensors (DTPS) and Direct Radon Progeny Sensors (DRPS) are developed which are depositions based systems and hence ensure that they respond only to the decay products and not to gas concentrations. The recently developed (by BARC) DRPS and DTPS technique for 222Rn and 222Rn progeny measurements for the present study will be better than previous available techniques viz. use of SSNTDs in bare and cup mode

  2. Estimation of the radon dose in buildings by measuring the exhalation rate from building materials

    We review the accumulator technique using active (CRM) and passive detectors (activated charcoal and electret). We describe the ERS2 detector, an electrostatic radon sampler followed by alpha spectrometry, with improved algorithm and adapted to measure the exhalation rate from walls. The technique produces accurate results over a broad range of materials: concrete, Pumice, ceramics, tiles, granite, etc. The measured exhalation rate is the same, within errors, as measured by the standard detectors

  3. Radon exhalation rates of concrete modified with fly ash and silica fumes

    The radiological impact of the environmental gas radon to the health of general public is of concern since many decades. Cement used for the construction blended with fly ash and silica fumes is recommended by Government in order to avoid the soil and environmental pollution. But these addition step-up the Indoor radon level in the dwelling due to radioactivity contents. The exhalation of radon from concrete blended with silica fumes and fly ash depends upon addition level, porosity, moisture and radioactivity content. In order to optimize the level of substitution of silica fumes and fly ash, measurements of radon exhalation rates from the concrete blended with different proportions of fly ash and silica fumes was carried out using active scintillation radon monitor. The effect of porosity, moisture, back diffusion and radioactivity content of the concrete on exhalation rates is studied. The measured exhalation rates were extrapolated for indoor radon concentration and effective dose equivalent using ICRP, 1987 recommendations. (author)

  4. Measurement of radium concentration and radon exhalation rate in building material samples

    Building materials are the main source of radon in the dwellings. Therefore measurement of radon exhalation rate from these materials will help in the prediction of existence of dwelling with potential radon risk. Radon exhalation rate from building materials varies with type and origin. Emanation of radon is associated with the presence of radium and its ultimate precursor uranium in the ground. Solid state nuclear track detectors (LR-115 TYPE-II) are used to determine radon exhalation rate in building material samples collected from the different locations of Himachal Pradesh. SSNTD mainly detects the alpha particles having energy ranging from 1.7 to 4.8 MeV. For this purpose, building materials are collected in plastic can containing LR-115 TYPE-II solid state nuclear track detectors which are very sensitive for alpha particles. The samples are granite, marble and sandstone. There is a large variation in values of radon exhalation rate which may be due to the difference in radium content. The exhalation rate for the measured samples varies from 40.72 mBqkg-1h-1(sandstone) to 81.40 mBqkg-1h-1(granite). From the results, it is clear that granite sample shows higher radon exhalation rate than that of marble and sandstone samples. The emanation coefficient and effective alpha dose equivalent is also calculated for the health risk assessment. (author)

  5. Fractal analysis of spatial distribution of radon exhalation rates of uranium mill tailings

    A uranium mill tailings, located in Guangdong, was selected for spatial distribution of the radon exhalation rates measured by local static method. The two-dimension surface of radon exhalation rates was established by Surfer using the data of spatial distribution of radon exhalation rates measured at August 14, 2007 to 19 and 21, which was analyzed by fractal method of projective covering. The results show that the two-dimension surface of radon exhalation rates is of fractal structure. The fractal dimension of surface of radon exhalation rates from August 14, 2007 to 19 and 21 are 2.0535, 2.0173, 2.0029, 2.0084, 2.0079, 2.0057 and 2.0034, respectively, which indicates that the complexity of spatial distribution of the radon exhalation rates at 14 and 15 are larger than that of the other days. The phenomenon results from the change of precipitation and temperature, as well as the features of uranium mill tailings, including mineral composition, particle size, radium content, porosity and pore connectivity, etc. (authors)

  6. Natural radioactivity and radon exhalation rate in Brazilian igneous rocks

    Moura, C.L.; Artur, A.C. [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil); Bonotto, D.M., E-mail: danielbonotto@yahoo.com.b [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil); Guedes, S. [Departamento de Cronologia e Raios Cosmicos, Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas (UNICAMP), Rua Sergio Buarque de Holanda No. 777, CEP 13083-859, Campinas, Sao Paulo (Brazil); Martinelli, C.D. [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil)

    2011-07-15

    This paper reports the natural radioactivity of Brazilian igneous rocks that are used as dimension stones, following the trend of other studies on the evaluation of the risks to the human health caused by the rocks radioactivity as a consequence of their use as cover indoors. Gamma-ray spectrometry has been utilized to determine the {sup 40}K, {sup 226}Ra and {sup 232}Th activity concentrations in 14 rock types collected at different quarries. The following activity concentration range was found: 12.18-251.90 Bq/kg for {sup 226}Ra, 9.55-347.47 Bq/kg for {sup 232}Th and 407.5-1615.0 Bq/kg for {sup 40}K. Such data were used to estimate Ra{sub eq}, H{sub ex} and I{sub {gamma}}, which were compared with the threshold limit values recommended in literature. They have been exceeded for Ra{sub eq} and H{sub ex} in five samples, where the highest indices corresponded to a rock that suffered a process of ductile-brittle deformation that caused it a microbrecciated shape. The exhalation rate of Rn and daughters has also been determined in slabs consisting of rock pieces {approx}10 cm-long, 5 cm-wide and 3 cm-thick. It ranged from 0.24 to 3.93 Bq/m{sup 2}/h and exhibited significant correlation with eU (={sup 226}Ra), as expected. The results indicated that most of the studied rocks did not present risk to human health and may be used indoors, even with low ventilation. On the other hand, igneous rocks that yielded indices above the threshold limit values recommended in literature may be used outdoors without any restriction or indoors with ample ventilation.

  7. A comparative study between the dynamic method and passive can technique of radon exhalation measurements from samples

    A comparative study has been carried out between the SSNTD based ‘can’ technique and active monitors based dynamic method using nine different samples, eight of granite and one of phosphogypsum. Besides radon (222Rn) exhalation, thoron(220Rn) exhalation and 226Ra and 232Th content were also measured. The results are: (i) presence of significant thoron exhalation from samples and (ii) observation of thoron interference and leak (~0.05 h−1) from the ‘can’ in the SSNTD based ‘can’ technqiue. The study unequivocally demonstrates the presence of intrinsic uncertainty in SSNTD based ‘can’ technique. Instead, dynamic method offers a more reliable and faster method. - Highlights: • Comparative study has been carried out between active and SSNTD based ‘can’ techniques. • Study showed large difference in measured radon and thoron exhalation rates. • Study unequivocally demonstrates the presence of intrinsic uncertainty in SSNTD based ‘can’ technique. • The uncertainty has been analyzed through thoron interference and leak effect

  8. Measurement of radon/thoron exhalation rates and gamma-ray dose rate in granite areas in japan

    Radon and thoron exhalation rates and gamma-ray dose rate in different places in Hiroshima Prefecture were measured Exhalation rates were measured using an accumulation chamber method. The radon exhalation rate was found to vary from 3 to 37 mBq m-2 s-1, while the thoron exhalation rate ranged from 40 to 3330 mBq m-2 s-1). The highest radon exhalation rat(37 mBq m-2 s-1) and gamma-ray dose rate (92 nGy hs-1, were found in the same city (Kure City). In Kure City, indoor radon and thoron concentrations were previously measured at nine selected houses using a radon-thoron discriminative detector (Raduet). The indoor radon concentrations varied from 16 to 78 Bq m-3, which was higher than the average value in Japan (15.5 Bq m-3). The indoor thoron concentration ranged from ND (not detected: below a detection limit of approximately 10 Bq m-3) to 314 Bq m-3. The results suggest that radon exhalation rate from the ground is an influential factor for indoor radon concentration. (authors)

  9. The influence of thoron on measurement results of radon exhalation rate

    Xiao De Tao; Ling Qiu; Leung, J K C

    2002-01-01

    Because of thoron exhalation, the measurement results of radon exhalation rate using a local still method is usually larger than the true value of radon flux rate of the monitored material surface. The influence of sup 2 sup 1 sup 6 Po(ThA) on radon exhalation rate can be eliminated for sensitive radon monitors. Theoretical evaluations of the influence of sup 2 sup 1 sup 2 Bi(ThC) and sup 2 sup 1 sup 2 Po(ThC')on radon exhalation rate are carried out in a sampler with diameter of 188 mm, and height of 125 mm, and supplied electrostatic field inside (generated by high voltage and electret) under following conditions: the sampling time are 1, 2, 3 h, respectively, thoron exhalation rate is 100 times of radon's. The calculation results indicate that the measurement results of radon flux rate are possibly 35.5% larger than true value due to the influence of thoron for fast and multifunctional radon monitors with electret, high voltage, respectively and using CR-39 SSNTD as detector, but this influence is negligib...

  10. Measurement of radon exhalation rate in some industries residue used in new type wall materials

    Objective: To study the radon exhalation rate in some industries residue used in new type wall materials. Methods: To determine the radon exhalation rate by the activated charcoal absorption and γ-ray spectrometer with HPGe detector. Results: The radon exhalation rate level is successively autoclaved aerated concrete block (9.70 ± 2.54 Bq·m-2·s-1, fly ash block (5.83 ± 1.85) Bq·m-2·s-1, gangue block (4.70±2.45) Bq·m-2·-1, clay block (2.63 ± 0.56) Bq·m-2·s-1. Conclusion: The average radon exhalation rate level of autoclaved aerated concrete block and fly ash block is significantly higher than that 1 of clay block, the differences is significant (P0.05). The gangue block is a ideal New Type Wall Material, whose radon exhalation is lower than that of autoclaved aerated concrete block and fly ash block. (authors)

  11. Indoor radon levels and their relationship with radon exhalation rates from building surface in Hong Kong

    The indoor radon concentrations of more than 60 sites in Hong Kong is measured using activated charcoal canisters to identify the underlying distribution pattern. The strong relationship between the indoor radon concentrations and the radon exhalation rate from building surface has been investigated. It has been found that the indoor radon comes mainly from radium in building materials, and that the radon concentration depends on the radon exhalation rate from indoor building surface and on the ventilation. It is also asserted that the radioactivity level of building materials used in Hong Kong is increasing

  12. A correlation study between indoor radon-thoron concentration and soil exhalation rates from Indian dwellings

    The measurements of indoor radon and thoron concentration in some north Indian dwellings were carried out using pin hole based radon thoron dosimeters. The inhalation doses were calculated by ICRP recommendations. The radon and thoron exhalation rates from the soil collected from the same dwellings area were also carried out with closed chamber technique using active measurement by scintillation radon monitor and scintillation thoron monitor. The indoor radon and thoron concentration varied from 12 to 90 Bq/m3 and 20 to 140 Bq/m3 respectively. A good positive correlation was found between indoor radon thoron concentration and their exhalation rates. (author)

  13. Determination of Radon Exhalation Rate From Building Material Using Passive Method With Nuclear Track Detector

    Passive method with Cr-39 nuclear track detector has been developed for the measurement of radon exhalation rate from building material with accuracy of 4% and reproducibility between 6-9%. The procedure is simple and applicable for using in field. For routine use, minimum detectable level of 0.026 Bq/m2 hour, if exposure time is 21 days. Based on preliminary study, radon exhalation rate around between 0.80 and 1.32 Bq/m2 hour, higher on white batako and lowest on light concentrate. Application of surface coating (plastering and latex paint), can reducing flux radon among 38 to 72 %

  14. Natural Radioactivity and 222Rn Exhalation Rate from Brazilian Phosphogypsum Building Materials

    Phosphogypsum is classified as a NORM residue and one of the main environmental concerns of its use is the radon exhalation from this material. The aim of this study is to determine the activity concentration of natural radionuclides, radium equivalent activities, external and internal hazard index and the radon exhalation rate from bricks and plates made of phosphogypsum. The activity concentration and radon exhalation rate were in accordance with literature values. The results of radium equivalent, external and internal hazard index showed that plates and bricks from Ultrafertil and Fosfertil presented values above the recommended limits; indicating the necessity of using more realistic models for the safe application of phosphogypsum as building materials. The results of this study can contribute for the establishment of guidelines by the Brazilian regulatory agency, for the safe use of phosphogypsum as building material. (author)

  15. Evaluation of dose arising from 222Rn, decay products of 222Rn and 220Rn to staff from a certain nuclear power plant

    The staff of the plant was grouped on their work ranges. The annual effective dose resulted from radon and the decay products of 222Rn/220Rn is studied by measuring radon concentration with double filter membrane method and by measuring the concentration of 222Rn/220Rn short life radioactive decay products with five-count method. Based on the results, specific protection measures are proposed for high radon areas. The study results show that the monitoring data for all areas except the spent fuel pool was smaller than the recommended values by ICRP. (authors)

  16. Environmental impact of radon exhalation rates and radio activity from various commodities: a review

    This study presents a review report of radon exhalation rate and natural radioactivity from various commodities such as fly ash of thermal power plants, soil, radiation shielding material etc. The perspective radiation shielding materials using fly ash and other commonly used construction have also been tested for the presence of natural radioactivity

  17. Primary investigation and study on 222Rn and 220Rn levels of underground coal mines in China

    From Dec. of 2002 to Aug. of 2004, by using Solid State Nuclear Track Detectors (SSNTDs), the 222Rn concentrations of 8 underground coal mines, i.e., Beijing Shijiaying, Beijing Fangshanchengguan, Shanxi Gujiaoxiqu, Shanxi Taiyuan Wangfang, Hunan Baifang, Hunan Songbai, Guizhou Honglin and Zhejiang Anrenjinjiang, Respectively, had been measured during a period of 12 months (once a three-month). The surveyed data showed that the annual average 222Rn concentrations (with number of measuring points) are 550(69), 3187(28), 45(224), 117(72), 88(79), 79(58), 40(72) and 136(116) Bq/m3, respectively. The 222Rn concentrations of underground coal mines vary with ventilation condition, geological structure and other factors, and the 222Rn concentration in the mine with bad ventilation is generally high, and varies with seasons i.e., higher in summer and autumn and lower in winter. The 222Rn concentration in mines with good ventilation is generally low and no notable variation with the season. These are also some characters of 222Rn levels in Chinese coal mines, such as the 222Rn concentrations in state-run coal mines are general low, but those in Beijing area are very high, and those in Zhejiang rock coal mines are not so high as expected, etc., the possible reasons have been discussed in the paper. The 220Rn levels of 4 coal mines in Beijing and Hunan were also measured, the ratios of alpha potential energy concentration of 220Rn daughters to that of 222Rn daughters are between 0.036 and 0.42. (authors)

  18. Evaluation of Radon-222 exhalation rate from uranium mine waste rock pile

    The 222 Rn exhalation from waste rock piles is an important item to be assessed in uranium mines decommissioning process. In this work are presented the INB-Caldas Uranium Mine waste rock pile number 4 (BF4) surface 222 Rn exhalation rate. The BF4 waste rock pile contains low concentration uranium ore, below the concentration needed to feed the uranium extraction milling plant, and its surface has been partially covered with clay to prevent acid drainage formation from air oxygen reaction with pyrite ore. The sample collection was performed using passive coal trap collectors for 222 Rn exhalation. The traps were placed on the waste rock pile surface during adequate collection periods and gamma counted after four hours to allow for radon daughters in growth. The waste rock pile (BF4) has been divided into five areas, according to mining periods. Measurements were made in three of these areas, during dry and rain seasons, 141 samples in all. The 222 Rn exhalation geometric mean (pCi/m-2.sec-1) obtained by area were 21.8±253 (min=0..6, max =1809) for area A; 11.9±33 (min=0.5, max=160) for area B; 6.6±11 (min=0.6, max=47) for area D. (author)

  19. Measurement of Radon Exhalation Rate in Sand Samples from Gopalpur and Rushikulya Beach Orissa, Eastern India

    Mahur, Ajay Kumar; Sharma, Anil; Sonkawade, R. G.; Sengupta, D.; Sharma, A. C.; Prasad, Rajendra

    Natural radioactivity is wide spread in the earth's environment and exists in various geological formations like soils, rocks, water and sand etc. The measurement of activities of naturally occurring radionuclides 226Ra, 232Th and 40K is important for the estimation of radiation risk and has been the subject of interest of research scientists all over the world. Building construction materials and soil beneath the house are the main sources of radon inside the dwellings. Radon exhalation rate from building materials like, cement, sand and concrete etc. is a major source of radiation to the habitants. In the present studies radon exhalation rates in sand samples collected from Gopalpur and Rushikulya beach placer deposit in Orissa are measured by using "Sealed Can technique" with LR-115 type II nuclear track detectors. In Samples from Rushikulya beach show radon activities varying from 389 ± 24 to 997 ± 38 Bq m-3 with an average value of 549 ±28 Bq m-3. Surface exhalation rates in these samples are found to vary from 140 ± 9 to 359 ± 14 mBq m-2 h-1with an average value of 197 ±10 mBq m-2 h-1, whereas, mass exhalation rates vary from 5 ± 0.3 to 14 ± 0.5 mBq kg-1 h-1 with an average value of 8 ± 0.4 mBq kg-1 h-1. Samples from Gopalpur radon activities are found to vary from 371 ± 23 to 800 ± 34 Bq m-3 with an average value of 549 ± 28 Bq m-3. Surface exhalation rates in these samples are found to vary from 133 ± 8 to 288 ± 12 mBq m-2h-1 with an average value of 197 ± 10 mBq m-2 h-1, whereas, mass exhalation rates vary from 5 ± 0.3 to 11 ± 1 mBq kg-1 h-1 with an average value of 8 ± 0.4 mBq kg-1 h-1.

  20. A note on "an erroneous formula in use for estimating radon exhalation rates from samples using sealed can technique".

    Mayya, Y S; Sahoo, B K

    2016-05-01

    In this note, we point out a serious fallacy in a formula that has appeared in literature for calculating the (222)Rn exhalation rates using the Solid-State Nuclear Track Detector (SSNTD) based sealed can technique. It is shown that this formula underestimates true exhalation rates by a factor of more than 10(6). Several publications have used this formula instead of the well-known Abu-Jarad formula and have reported unrealistically low (µBq/m(2)/d) surface exhalation rates for normal materials. PMID:26896680

  1. Radon exhalation rates and effective radium contents of the soil samples in Adapazarı, Turkey

    Kuş, Adem; Yakut, Hakan; Tabar, Emre

    2016-03-01

    In this study effective radium content and radon exhalation rates in soil samples collected from Adapazarı district of Sakarya, Turkey have been measured using LR-115 type-II plastic track detectors by closed-can technique for the first time. The obtained effective radium contents are found to vary from 6.66 to 34.32 Bqkg-1 with a mean value of 18.01 Bqkg-1. The radon exhalation rates measured in terms of mass and area of soil samples are found to vary from 50.35-259.41 mBqkg-1h-1 with a mean value of 136.12 mBqkg-1h-1 and 1035.18-5333.39 mBqm-2h-1 with a mean value of mBqm-2h-1. All the measurements show that the values of radium content are under the safe limit recommended by Organization for Cooperation and Development.

  2. Measurement of radon exhalation rates in some soil samples collected from Western Haryana

    Indoor radon has been recognized as one of the health hazards for mankind. Common building materials used for construction of houses are considered as major sources of radon gas in indoor environment. In the present work, the radon exhalation rates were measured using 'Canister' technique. The alpha sensitive solid state nuclear track detector (LR-115 type-II) were used in the canisters for recording tracks produced by alpha particles from radon gas emanated from building materials. The samples of soil, were collected from Western districts of Haryana, India. The detectors were exposed in the canisters for 100 days. After the exposure time the detectors were etched using 2.5 N NaOH solution at 60℃ for 1.5 hours. The track density was found using an optical microscope at a magnification 600X. The mass and surface exhalation rates are also calculated from the data. (author)

  3. Modelling radiation exposure in homes from siporex blocks by using exhalation rates of radon

    Nikolić Mladen D.

    2015-01-01

    Full Text Available Building materials are the second major source of indoor radon, after soil. The contribution of building materials to indoor radon amount depends upon the radium content and exhalation rates, which can be used as a primary index for radon levels in the dwellings. This paper presents the results of using the experimentally determined exhalation rates of siporex blocks and concrete plates, to assess the radiation exposure in dwellings built of siporex blocks. The annual doses in rooms have been estimated depending on the established modes of ventilation. Realistic scenario was created to predict an annual effective dose for an old person, a housewife, a student, and an employed tenant, who live in the same apartment, spending different periods of time in it. The results indicate the crucial importance of good ventilation of the living space.

  4. Open charcoal chamber method for mass measurements of radon exhalation rate from soil surface.

    Tsapalov, Andrey; Kovler, Konstantin; Miklyaev, Peter

    2016-08-01

    Radon exhalation rate from the soil surface can serve as an important criterion in the evaluation of radon hazard of the land. Recently published international standard ISO 11665-7 (2012) is based on the accumulation of radon gas in a closed container. At the same time since 1998 in Russia, as a part of engineering and environmental studies for the construction, radon flux measurements are made using an open charcoal chamber for a sampling duration of 3-5 h. This method has a well-defined metrological justification and was tested in both favorable and unfavorable conditions. The article describes the characteristics of the method, as well as the means of sampling and measurement of the activity of radon absorbed. The results of the metrological study suggest that regardless of the sampling conditions (weather, the mechanism and rate of radon transport in the soil, soil properties and conditions), uncertainty of method does not exceed 20%, while the combined standard uncertainty of radon exhalation rate measured from the soil surface does not exceed 30%. The results of the daily measurements of radon exhalation rate from the soil surface at the experimental site during one year are reported. PMID:27132250

  5. Measurement of radon exhalation rates, natural environmental radioactivity and radiation exposure from Indian commercial granites

    Uranium is a radiotoxic element found in trace quantities in almost all naturally occurring materials like soil, rocks, and sand etc. Building materials are derived from these materials and are the main source of radon inside the dwellings. Several varieties of granites are produced and used as flooring materials and as ornamental stones in buildings in India. Commercial type of granites with specific names corresponds to geographical and geological origins and mineral compositions. The natural radioactivity present in rocks having high radiation levels are associated with granites. Measurement of radon exhalation rates for granite samples were carried out through sealed can technique using -115 type II detectors. Wide variation in radon exhalation rates is found in the samples. Radon activity is found to vary from 380.0 to 4258.6 Bq m-3 with an average value of 1316.2 m-3, whereas radon exhalation rate varies from 227.4 to 2548.8m Bq m-2 h-1 with an average value of 854.7 m Bq m-2 h-1. The variation can be correlated with the color of the granites. Effective dose equivalent, estimated from exhalation rate varies from 26.8 to 300.6 Sv y-1 with an average value of 100.8 Sv y-1. Activity concentrations of naturally occurring radionuclides (226Ra, 232Th and 40K) were also measured in these samples using high resolution γ-ray spectroscopic system. Gamma spectrometric measurements were carried out at Inter-University Accelerator Centre, New Delhi using a coaxial n-type HPGe detector (EG and G, ORTEC, Oak Ridge, USA). The detector has a resolution of 2.0 keV at 1332 keV and relative efficiency of 20%. It was placed in 4 inch shield of lead bricks on all sides to reduce the background radiation from building materials and cosmic rays

  6. Estimation of radon exhalation rate in Gopalpur beach sand samples Orissa, Eastern India

    In the present studies radon exhalation rates in sand samples collected from Gopalpur beach placer deposit in Orissa are measured by using 'Sealed can technique' using type LR 115-II nuclear track detectors. Radon activities are found to vary from 371.4 ± 23.0 to 800.0 ± 33.8 Bqm-3 with an average value of 549.2 ± 27.8 Bqm-3. Surface exhalation rates in these samples are found to vary from 133.4 ± 8.3 to 287.7 ± 12.1 mBqm-2h-1 with an average value of 197.2 ± 9.9 mBqm-2h-1, whereas, mass exhalation rates vary from 5.1 ± 0.3 to 11.1 ± 0.5 mBqkg-1h-1 with an average of 7.6 ± 0.4 mBqkg-1h-1. (author)

  7. Measurement of radon exhalation rate from fly ash samples generated in some major thermal power stations

    Coal-fired thermal power stations account for a majority of the electricity produced in India (about 70%). The coal used in thermal power stations have as high as 35 to 40% ash content resulting in generation of huge quantities of fly ash, a waste product product produced due to the burning of coal. The ever-increasing demand for electricity necessitates the need for the productive utilization of fly ash. One of the areas of major areas of utilization is mixing of fly ash in cement and bricks used for construction of dwellings and office premises. There has been apprehension among the public and environmentalists on the use of fly ash as it contains trace quantities of naturally occurring radioactive materials. Fly ash samples from some of the major thermal power stations across the country were collected and the radon exhalation rates were estimated experimentally using 'can' technique. This technique is a simple and widely-used method for the estimation of exhalation rate measurements. 50 grams fly ash samples were placed in a petri-dish. LR-115 film was affixed at the bottom of the lid of the petri-dish and sealed. Radon gas was allowed to accumulate in the dish for a period of one month, at the end of which the films were retrieved and processed. The radon exhalation rate from the samples analyzed varied between 0.01 and 0.05 Bq kg-1h-1. (author)

  8. Radon exhalation rate from the soil, sand and brick samples collected from NWFP and FATA (Pakistan))

    In order to characterise the building materials as an indoor radon source, knowledge of the radon exhalation rate from these materials is very important. In this regard, soil, sand and brick samples were collected from different places of the North West Frontier Province (NWFP) and Federally Administered Tribal Areas (FATA) (Pakistan)). The samples were processed and placed in plastic containers. NRPB radon dosemeters were installed in it at heights of 25 cm above the surface of the samples and containers were then hermetically sealed. After 40-80 d of exposure to radon, CR-39 detectors were removed from the dosemeter holders and etched in 25% NaOH at 80 deg. C for 16 h. From the measured radon concentration values, 222Rn exhalation rates were determined. Exhalation rate form soil, sand and brick samples was found to vary from 114 ± 11 to 416 ± 9 mBq m-2 h-1, 205 ± 16 to 291 ± 13 mBq m-2 h-1 and 245 ± 12 to 365 ± 11 mBq m-2 h-1, respectively. (authors)

  9. Measurement of radon activity and exhalation rate in soil samples from Banda district, India

    Radon activities and radon exhalation rates have been measured in soil samples collected from different location of Banda district of Uttar Pradesh in India using LR-115 type II solid state nuclear track detectors. Radon activity has been found to vary from (101.0) to (505.1) Bq/m3 with an average value of (278.3) Bq/m3. Surface exhalation rate has been found to vary from (84.0) to (419.8) mBq/m2/h with an average value (231.3) mBq/m2/h, whereas mass exhalation rate has been found to vary from (2.1) mBq/kg/h to (10.6) mBq/kg/h with an average value of (5.8) mBq/kg/h. Effective dose from indoor inhalation exposure (radon) has been estimated, which is found to vary from (6.1) to (30.5) μSv/year with an average value of (16.8) μSv/year. (author)

  10. Active measurement of radon and thoron exhalation from soil and building materials samples and effect of grain size

    Radon (222Rn) and Thoron (220Rn) emission from soil and building materials is considered as primary sources for inhalation dose to a person in indoor environment. In view of this, experiments have been carried out to determine radon and thoron emission from samples of soil and building materials using BARC developed smart radon and thoron monitor. Samples that were subjected to analysis included soil, sand, cement, flyash, POP, snewcem, lime powder, chalk putty and wallputty. Each sample was kept in a leak tight metal chamber, connected to a radon/thoron monitor to measure radon and thoron concentration at different time interval. Thoron being short-lived (half life of 55.6 s), a minimum thickness of building material was maintained such that the thoron surface exhalation rate will be independent of sample size. In case of radon, the air volume of the set up was kept sufficient enough to neglect the possible back diffusion effect. The influence of grain size on radon and thoron exhalation rates in soil and fly ash samples has been investigated by measuring the packing density and % porosity of samples. (author)

  11. Radium and radon exhalation rate in soil samples of Hassan District of South Karnataka

    Radon is present in both indoor and outdoor air due to the decay of 226Ra, which is present everywhere in the Earth's crust with varying concentration. Among many factors affecting radon exhalation, one of the most important is radium content of the bed rock or soil. Higher values of 226Ra in soil contribute significantly in the enhancement of environmental radon. Radon has a half-life of 3.82 days and it is chemically inert. Radon gas from soil is considered to be the most important source and it enters house mainly through cracks in the building structure. Radon and its daughter products are the major sources of radiation exposure and are recognized as one of the health hazard for mankind. In view of this, studies on the radon have assumed great significance worldwide. In the present work, an attempt was made to assess the radon exhalation rate in the environment of Hassan district of south Karnataka. Radon exhalation rate was determined by 'sealed can technique' using alpha sensitive solid state nuclear track detectors (LR-115 Type-II). The exposed films were etched with 2.5 N NaOH solution for 60 min at 60°C. The activity was counted using Spark Counter. Radon activity was found to vary from 19.3 ± 5.8 Bq m-3 to 224.0±31.5 Bq m-3 and radium equivalent activity varied from 103.4 ± 31.4 mBq kg-1 to 1198.7±16.8 mBq kg-1. Surface exhalation rate of radon vary from 13.3 ± 5.2 mBq m-2 h-1 to 154.2 ± 26.3 mBq m-2 h-1 and mass exhalation rate of radon vary from 2.7 ± 0.8 mBq kg-1 h-1 to 30.9 ± 4.36 mBq kg-1 h-1. The results of this systematic investigation are presented and discussed in the paper. (author)

  12. Development of a PIN diode based on-line measurement system for Radon (222Rn) and Thoron (220Rn) in environment

    Radon, thoron and their progenies are universally present in outdoor air, and can reach higher levels in indoor air due to poor ventilation. Several instruments have been developed for accurate measurement of radon and thoron in the environment. Semiconductor detector based system employing spectroscopic method has been proved to be the best among them. A PIN diode based electrostatic collection type online real-time instrument has been developed in Bhabha Atomic Research Centre for simultaneous measurement of radon and thoron in an environment while both 222Rn and 220Rn are present. This system can be used for determination of radon and thoron concentrations at residence or workplace. Furthermore, since the 222Rn and 220Rn are differentiated from each other through spectroscopy, this monitor can be used even in a mixed radon/thoron environment

  13. Development of a PIN diode-based on-line measurement system for radon (222Rn) and thoron (220Rn) in the environment

    A silicon PIN diode-based electrostatic collection type online real-time instrument has been developed for simultaneous measurement of radon (222Rn) and thoron (220Rn). The system, discussed in this paper, utilizes a hemispherical metal chamber (volume 1 L) for active air sampling. Estimation of 222Rn/220Rn concentration is carried out through alpha spectroscopy of electro-deposited polonium atoms on the detector surface. The system description and the characterization studies carried out with this instrument are presented here. Its performance has been tested with reference equipments. The instrument showed sensitivity of 0.408 counts per hour (CPH)/(Bq/m3) and 0.169 CPH/(Bq/m3) for radon and thoron measurements, respectively, at an optimized collection voltage of + 1.6 kV and relative humidity <10%. (author)

  14. Continuous on-line calibration of diffusive soil-atmosphere trace gas transport using vertical 220Rn- and 222Rn-activity profiles

    Continuous monitoring of 220Rn- and 222Rn-activities above and below the soil surface combined with sporadic direct 222Rn-flux measurements is used to quantify diffusive trace gas transport in the air-filled pore space of soil, through the soil-atmosphere interface and in the lowest layers of the atmosphere. In a calm night, 222Rn-activities above the surface first build-up near the ground (z 222Rn-flux from activity profiles measured in soil gas, (2) from direct flux determinations and (3) using information about atmospheric diffusion parameters from 220Rn-activities measured near the surface it is possible to model the temporal evolution of the vertical 222Rn-profiles in a night with stable weather and constant soil conditions. The system operates automatically for extended periods of time in the field enabling a better understanding of transport processes in response to changing environmental conditions (wind, rain, soil humidity). (orig.)

  15. Dynamics, deterministic nature and correlations of outdoor 222Rn and 220Rn progeny concentrations measured at Bacau, Romania

    The long-term variation, nature and correlations of outdoor 222Rn and 220Rn progeny concentrations measured during the period 1994-2009 were investigated. The time series of data were obtained within the framework of the monitoring program performed by the Environmental Radioactivity Monitoring Station (ERMS) Bacau, a component part of the National Environmental Radioactivity Survey Network (NERSN), coordinated by National Environmental Protection Agency (NEPA). The measuring method is based on the total beta measurements of atmospheric aerosol filters, using a low background total beta counter and (90Sr/Y) reference standard. Analysis of the time series of progeny concentrations in the low atmosphere makes evident different patterns of variation of these concentrations: diurnal, seasonal and annual. A possible relationship of progeny concentration increase with global warming is emphasized. In order to find the dominant frequency of the physical processes determining progeny concentration variability the power spectrum has been used. The deterministic nature of the time series of concentrations has been studied making use of the autocorrelation function and stationarity of the original data and of their phase randomized time series. Also, the correlations with meteorological parameters have been investigated using Pearson's correlation coefficient with corresponding level of significance. - Highlights: → Radon and thoron progeny concentrations measured on a period of 16 years. → 5 h, daily, monthly and annual patterns are pointed out. → Autocorrelation functions prove non-randomness of concentrations. → Deterministic nature of time series of concentrations is demonstrated. → Correlations with meteorological data are studied.

  16. Radon exhalation rate from the building materials of Tiruchirappalli district (Tamil Nadu State, India)

    Tiruchirappalli district has enriched resources of building materials such as stone, granite, sand, brick, cement, etc., which are also supplied to the neighbouring districts. Since radon is considered as one of the causative factors for human lung diseases, the measurement of the radon level in these building materials is imperative for the assessment. The samples of building materials were collected from their original sources spread over Tiruchirappalli district. The sealed can technique with solid state nuclear track detector (SSNTD) was employed for the measurement of radon exhalation. The activity concentrations of radon in sedimentary rocks analyzed ranged from 13.2 Bq/m3 to 218.0 Bq/m3 with the geometric mean activity of 46.3 Bq/m3. However, radon concentrations in igneous rocks are distinctly higher than those of sedimentary rocks and ranged from 95.6 Bq/m3 to 1140 Bq/m3 with the geometric mean activity concentration of 392.6 Bq/m3. The radon exhalation from sand, brick, and cement were found to be non-uniform (sand: 119.8-656 Bq/m3, brick: 31-558 Bq/m3, cement: 172-300 Bq/m3). The activity concentration of radon in these building materials follow a descending order: Granite > sand > cement > brick > sand stone. The mass and surface exhalation (EM and EA) rates also follow the same order. The study concludes that since the radon exhalation from the building materials was less than the International Commission on Radiological Protection limit of 1500 Bq/m3, they do not pose any radiological risk. (author)

  17. Effect of moisture on the radon exhalation rate from soil, sand and brick samples collected from NWFP and FATA (Pakistan))

    A series of experiments were carried out to study the effect of the moisture content on the radon exhalation rate from soil, sand and brick samples that were collected from the North West Frontier Province and Federally Administered Tribal Areas of Pakistan, using CR-39-based radon dosimeters. After processing, samples were prepared by adding 15, 30 and 45% moisture contents (by weight) and were placed in plastic containers. The dosimeters were installed in it at heights of 25 cm above the surface of the samples. These containers were then hermetically sealed and the dosimeters were exposed to radon for 60 to 65 days. After exposure, CR-39 detectors were etched in 25% NaOH at 80 deg.C for 16 h, and track densities were counted. From the measured track densities, exhalation rate was determined using two different approaches. Maximum average radon exhalation rates of 385 ± 86, 393 ± 31 and 362 ± 36 mBq m2 h-1 were observed at 30% moisture content from soil, sand and brick samples, respectively. A slight decrease in exhalation rate was observed in all samples at moisture content of 45%. According to the t-test, change in the exhalation rate as a function of humidity is significant at 95% confidence level. (authors)

  18. Radon exhalation rate from coal ashes and building materials in Italy

    The Italian National Electricity Board, in cooperation with Centro Informazioni Stubi Esperienze (CISE) has a program to assess the hazards connected with using fly ash in civil applications as partial substitutes for cement and other building materials. We investigated the natural radioactivity levels of more than 200 building materials. The survey involved materials available in Italy, categorized by geographical location and type of production. We also examined approximately 100 samples of fly ash from United States and South African coal, obtained from Italian power plants. Exhalation rates from about 40 powdered materials were determined by continuously measuring radon concentration growth in closed containers. Measurements were also performed on whole bricks, slabs, and titles. Details about the high-sensitivity measuring devices are presented. The influence of fly ash on exhalation rates was investigated by accurately measuring radon emanation from slabs with various ash/cement ratios and with slabs of inert materials having various radium concentrations. We will discuss results of forecasting indoor radon concentrations under different ventilation conditions. Two identical test rooms are being built, one with conventional and one with fly-ash building materials, to compare theoretical calculations with experimental data. Specifications for instruments to control and to measure the most important parameters are also discussed

  19. Radon activity and exhalation rates in coal fired thermal power plants

    The combustion of coal in various thermal power plants results in the release of some natural radioactivity to the atmosphere through formation of fly ash and bottom ash or slag. This consequently increases the radioactivity in soil, water and atmosphere around thermal power plants. As the radon in the atmosphere (indoor and outdoor), soil, ground water, oil and gas deposits contributes the largest fraction of the natural radiation dose to populations, enhanced interest exhibited in tracking its concentration is thus fundamental for radiation protection, health and hygiene point of view. In the present study, measurements of radon emanation from coal, fly ash, soil and water samples collected from five thermal power plants of north India have been made using SSNTDs. The average values of radon emanation at equilibrium in the air volume of Cans above different samples varied from 433 ± 28 Bq m-3 to 2086 ± 36 Bq m-3; mass exhalation rates from 13 mBq kg-1 hr-1 to 168 mBq Kg-1hr-1 and surface exhalation rates from 302 mBq m-2hr-1 to 1482 mBq m-2hr-1. The measured average radon concentration in the atmosphere of the thermal power plants have been found to vary from 558 ± 40 Bq m-3 to 682±60 Bq m-3. Based upon these values, the average annual effective doses have also been calculated. (author)

  20. Survey of Gamma Dose and Radon Exhalation Rate from Soil Surface of High Background Natural Radiation Areas in Ramsar, Iran

    Rouhollah Dehghani

    2013-09-01

    Full Text Available Background: Radon is a radioactive gas and the second leading cause of death due to lung cancer after smoking. Ramsar is known for having the highest levels of natural background radiation on earth. Materials and Methods: In this research study, 50 stations of high radioactivity areas of Ramsar were selected in warm season of the year. Then gamma dose and radon exhalation rate were measured.Results: Results showed that gamma dose and radon exhalation rate were in the range of 51-7100 nSv/hr and 9-15370 mBq/m2s, respectively.Conclusion: Compare to the worldwide average 16 mBq/m2s, estimated average annual effective of Radon exhalation rate in the study area is too high.

  1. Prediction of 222 Rn exhalation rates from phosphogypsum based stacks. Part I: parametric mathematical modeling

    Radon-222 is a radionuclide exhaled from phosphogypsum by-produced at phosphate fertilizer industries. Alternative large-scale application of this waste may indicate a material substitute for civil engineering provided that environmental issues concerning its disposal and management are overcome. The first part of this paper outlines a steady-state two-dimensional model for 222Rn transport through porous media, inside which emanation (source term) and decay (sink term) exist. Boussinesq approach is evoked for the laminar buoyancy-driven interstitial air flow, which is also modeled according to Darcy-Brinkman formulation. In order to account for simultaneous effects of entailed physical parameters, governing equations are cast into dimensionless form. Apart from usual controlling parameters like Reynolds, Prandtl, Schmidt, Grashof and Darcy numbers, three unconventional dimensionless groups are put forward. Having in mind 222Rn transport in phosphogypsum-bearing porous media, the physical meaning of those newly introduced parameters and representative values for the involved physical parameters are presented. A limiting diffusion-dominated scenario is addressed, for which an analytical solution is deduced for boundary conditions including an impermeable phosphogypsum stack base and a non-zero fixed concentration activity at the stack top. Accordingly, an expression for the average Sherwood number corresponding to the normalized 222Rn exhalation rate is presented

  2. Environmental impact of radon exhalation rates and radioactivity from various commodities: a review

    Natural radioactivity and its effects on human health is a major environmental concern because of the discovery of widespread occurrence of levels of radon in the ambient air of homes at concentrations that exceed the maximum levels given by the environmental protection agencies. Natural sources of radiation are the concentrations of radionuclides that represent ambient conditions present in the environment which are influenced by human activities. This study presents a review report on natural radioactivity and radon exhalation rate from various commodities such as fly ash of thermal power plants, soil, radiation shielding material etc., from northern and partly eastern part of India which covers Jaduguda uranium mines and others. Most of the building materials of natural origin contain small amounts of Naturally Occurring Radioactive Materials (NORM) and Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) using fly ash etc. For the natural radioactivity measurement, gamma ray spectrometer was used whereas the radon surface and mass exhalation rates were studied using SSNTDs. The perspective radiation shielding materials using fly ash and other commonly used construction materials have also been investigated for the presence of natural radioactivity. Emphasis was given on the perspective radiation shielding materials using up to 20-25% of fly ash. The radiation attenuation properties were studied for perspective radiation shielding materials using simulation codes and experimental data which shows good agreement between simulation results and experimental values. The radon activity in various samples varies from 20 Bqm-3 to 300 Bqm-3, radon mass and surface exhalation rates were found to vary from 1.05±0.07 to 22±1.2 mBqKg-1h-1 and 9.0±0.30 to 40±1.5 mBqm-2h-1 respectively. Most dominant activity found in the Jaduguda samples, which is due to the presence of uranium in the host rocks and the prevalence of a confined atmosphere within

  3. Measurements of natural radioactivity and radon exhalation rates from different brands of cement used in Pakistan

    The measurement of activity due to the naturally occurring radionuclide has been carried out in different brands of cement available in Pakistan. The gamma spectra of the collected samples were obtained using high-purity germanium detector and analysed for the presence of 232Th, 238U and 40K. The assessment of radiological hazards due to these radionuclides has also been made. The studies concerning the determination of radon-exhalation rates from these samples of cement were also carried out using CR-39 based NRPB radon dosimeters. The range of activity concentrations were found for 226Ra (from 25.10 ± 1.55 to 52.60 ± 3.20 Bq kg-1), 232Th (from 10.30 ± 0.65 to 30.40 ± 1.70 Bq kg-1) and 40K (from 17.25 ± 1.55 to 292.95 ± 23.05 Bq kg-1). The estimated value of radium equivalent concentration was from 11.16 ± 2.60 to 114.98 ± 7.11 Bq kg-1. The calculated absorbed dose rate in air and the annual effective dose were in the range from 18.54 ± 1.17 to 52.90 ± 3.31 nGy h-1 and 0.09 ± 0.01 to 0.26 ± 0.02 mSv, respectively. The external and internal hazard indices were in the range from 0.11 ± 0.01 to 0.31 ± 0.02 and 0.18 ± 0.01 to 0.45 ± 0.03, respectively. The radon exhalation rates from different brands of cement were found in the range from 3.3 ± 0.7 to 8.1 ± 1.7 mBq kg-1 h-1. (authors)

  4. Modeling of indoor radon concentration from radon exhalation rates of building materials and validation through measurements

    Building materials are the second major source of indoor radon after soil. The contribution of building materials towards indoor radon depends upon the radium content and exhalation rates and can be used as a primary index for radon levels in the dwellings. The radon flux data from the building materials was used for calculation of the indoor radon concentrations and doses by many researchers using one and two dimensional model suggested by various researchers. In addition to radium content, the radon wall flux from a surface strongly depends upon the radon diffusion length (L) and thickness of the wall (2d). In the present work the indoor radon concentrations from the measured radon exhalation rate of building materials calculated using different models available in literature and validation of models was made through measurement. The variation in the predicted radon flux from different models was compared with d/L value for wall and roofs of different dwellings. The results showed that the radon concentrations predicted by models agree with experimental value. The applicability of different model with d/L ratio was discussed. The work aims to select a more appropriate and general model among available models in literature for the prediction of indoor radon. -- Highlights: • The measurement of indoor radon concentration was carried out by pin hole based dosimeter. • The indoor radon concentration was calculated from different model available in the literature. A comparison of wall flux from two different approaches was carried out for different d/L ratio. • A more appropriate model for prediction of indoor radon concentration was validated

  5. Determination of radon and thoron exhalation rate from the walls surface by CR-39 track detectors

    Solid-state nuclear track detectors are finding expanded uses in various environment research investigations. Inhalation dose due to indoor radon/thoron and their short lived progeny concentrations constitute a major part of the total natural background radiation received by the population. Many measurements of radon concentration in the environment also involve using a dosimeter containing solid state nuclear track detector. The walls of houses included building materials such as granite, bricks, sand, cement etc., contain uranium and thorium in various amounts. Therefore the knowledge of true value exhalation rate of Rn and Tn from building materials represents scientific and practical interest in environmental radiation protection and ecology. In the present work, we have used calibrated plastic cups with two CR-39 detectors. The first detector fixed on bottom of cup in distance of cup height from walls surface and records alpha particles from radon only. The second detector fixed on the top of cup and records alpha particles from thoron and radon. The detected surface of the cup is situated in perpendicular position to surface of the wall. The detectors were exposed for 20-30 days. After exposition, the detectors were chemically etched and analyzed. The exhalation rate per unit area of the concrete, fired and unfired brick walls varied 0.091, 0.078 and 0.1 Bq m-2 h-1 for the radon, 3470, 200 and 5800 Bq m-2 h-1 for the thoron, accordingly. The number and location of radon and thoron alpha tracks were determined using an optical microscope and an image analysis system based on special developed software. The software for track images treatment by application of digital image processing has been developed. All program modules are made in DELPHI execution environment by using Pascal object-oriented language.

  6. National survey on the natural radioactivity and Rn-222 exhalation rate of building materials in the Netherlands

    de Jong, P.; van Dijk, W.; van der Graaf, E.R.; de Groot, A.V.

    2006-01-01

    The present study reports on results of a nationwide survey on the natural radioactivity concentrations and Rn-222 exhalation rates of the prevailing building materials in the Netherlands. In total 100 samples were taken and analyzed for the activity concentrations of Ra-226, Ra-228, Th-228, and K-4

  7. Radon exhalation rate and natural radionuclide content in building materials of high background areas of Ramsar, Iran

    Radon exhalation rates from building materials used in high background radiation areas (HBRA) of Ramsar were measured using an active radon gas analyzer with an emanation container. Radon exhalation rates from these samples varied from below the lower detection limit up to 384 Bq.m−2 h−1. The 226Ra, 232Th and 40K contents were also measured using a high resolution HPGe gamma- ray spectrometer system. The activity concentration of 226Ra, 232Th and 40K content varied from below the minimum detection limit up to 86,400 Bq kg−1, 187 Bq kg−1 and 1350 Bq kg−1, respectively. The linear correlation coefficient between radon exhalation rate and radium concentration was 0.90. The result of this survey shows that radon exhalation rate and radium content in some local stones used as basements are extremely high and these samples are main sources of indoor radon emanation as well as external gamma radiation from uranium series. -- Highlights: ► In the selection process of local samples, portable scintillometer (NaI) was used. ► The activity concentration of 226Ra varied from below the MDL up to 86400 Bq kg−1. ► The activity concentration of 232Th varied from below the MDL up to 187 Bq kg−1. ► The activity concentration of 40K varied from below the MDL up to 1350 Bq kg−1

  8. Uranium, Radium and Radon Exhalation rate in the soil samples from some areas of Punjab and Haryana states, India

    Uranium, radium concentration and radon exhalation rate have been determined in soil samples from some areas of Punjab and Tusham (Haryana), using the LR-115 plastic track detectors. 'Can Technique' using these detectors, has been used for the estimation of radium concentration and radon exhalation rate and uranium estimation has been carried out in the samples using the fission track technique. Uranium content in these samples has been found to be varying from 1.03 to 9.96 ppm in the Punjab region and varies from 3 to 13.4 ppm for Tusham region. Radium concentration observed for soil samples has been found to be varying from 0.82 to 8.6 Bq Kg-1 for Punjab area and from 2 to 9.31 Bq Kg-1 for Tusham. The Radon exhalation rate in these samples has been found to be varying from 1.2 to 8.83 mBq Kg-1h-1 for Punjab area and from 3.11 to 11.54 mBq Kg-1h-1 for Tusham. A positive correlations with (R2 =0.61) and (R2=0.60) have been found between radon exhalation rate and uranium concentration in the samples from both for the Punjab and Tusham regions respectively. (authors)

  9. Natural 222Rn and 220Rn indicate the impact of the Water–Sediment Regulation Scheme (WSRS) on submarine groundwater discharge in the Yellow River estuary, China

    Highlights: • 220Rn and 222Rn were combined to locate intensive SGD sites. • Influence of WSRS to SGD was found for the first time. • SGD was a dominant nutrient pathway in the Yellow River estuary. - Abstract: Submarine groundwater discharge (SGD) in estuaries brings important influences to coastal ecosystems. In this study, we observed significant SGD in the Yellow River estuary, including a fresh component, during the Water–Sediment Regulation Scheme (WSRS) period. We used the 222Rn and 220Rn isotope pair to locate sites of significant SGD within the study area. Three apparent SGD locations were found during a non-WSRS period, one of which became much more pronounced, according to the remarkably elevated radon levels, during the WSRS. Increased river discharge (from 245 m3 s−1 to 3560 m3 s−1) and the elevated river water level (from 11 m to 13 m) during the WSRS led to a higher hydraulic head, enhancing groundwater discharge in the estuary. Our results suggest that high river discharge (>3000 m3 s−1) might be necessary for elevated fresh submarine groundwater discharging (FSGD). Vertical profiles of salinity, DO and turbidity anomalies along the benthic boundary layer also indicated significant FSGD in the estuary during the WSRS. Nutrient concentrations had positive correlations with 222Rn during a 24-h observation, which indicates that SGD is a dominant nutrient pathway in this area

  10. Radon exhalation in some building construction materials and effect of plastering and paints on the radon exhalation rate using fired bricks

    The technological endeavors of human beings have modified the levels of radiation exposure slightly. The emanation of radon is primarily associated with radium and its ultimate precursor uranium. The radiation dose received by human beings from indoor radon and its progeny is the largest of all doses received either by natural or man-made sources. In order to investigate the effect of paints available in the market on the radon exhalation rate from building materials, several bricks were collected. These bricks were plastered with a mixture of cement and sand. Before measurements bricks were dried for 24 hours. These plastered bricks were then coated with white wash and again dried for 1- 2 hours. After drying the bricks were coated with different brands and colors of paints. Radon exhalation rates measurements were carried out for these painted bricks using 'Sealed can Technique' cylindrical plastic 'Can' of 7.5 cm height and 7.0 cm diameter was sealed to the individual samples by plastic can. In each 'Can' a LR-115 type II plastic detector (2 cm 2cm) was fixed at the top inside of the 'Can', such that the sensitive surface of the detector faces the material and is freely exposed to the emergent radon. Radon decays in the volume of the can record the alpha particles resulting from the 218Po and 214Po deposited on the inner wall of the 'Can'. Radon and its daughters will reach an equilibrium in concentration after one week or more. Hence the equilibrium activity of the emergent radon can be obtained from the geometry of the can and the time of exposure. The results will be discussed. (author)

  11. {sup 220}Rn measurements and implications for earlier surveys of {sup 222}Rn; Meting van {sup 220}Rn en consequenties voor eerdere {sup 222}Rn-surveys. VERA-onderzoek

    Blaauboer, R.O.

    2010-08-15

    The concentration of radioactive radon gas (Rn-222) encountered in newly constructed dwellings was lower than that expected from earlier surveys. An investigation into the response of the radon detectors used in these earlier surveys revealed that these were also sensitive to radioactive thoron (Rn-220), of which more appears to be present than originally assumed. This is the primary outcome of a detailed examination of the detectors that resulted from a national study on radiation exposure in Dutch dwellings constructed between 1994 and 2003. Detectors used in international radon comparison studies have only been set to test for radon, not thoron. Consequently, in practice it is not immediately evident that some detectors actually measure thoron as well, which is also reported as radon. The increasing interest shown by the Netherlands for thoron, provoked by survey results that appear to have been strongly affected by this radioactive isotope of radon, is mirrored by many other countries. The thoron found in dwellings seems to originate from a (frequently used) building material, possibly a finishing material, which has a relatively high thoron exhalation rate. It has more recently been determined that for many years a type of plaster was used in the Netherlands that contained phosphogypsum, a material known for its high radon content. However, it is possible that other materials incorporated into finishing layers also contribute to higher indoor thoron levels. A large portion of the total indoor exposure of occupants to radiation is from inhalation of radioactive decay products of radon and thoron. Radon and thoron are formed in the soil and earth-based building materials by radioactive decay and, because they are gaseous, they are able to diffuse into homes and other buildings. Exposure to ionizing radiation in the home accounts for approximately half of the average annual radiation dose received by a Dutch citizen. [Dutch] Er komt minder radioactief radongas

  12. LR-115 detector response to 222Rn, 220Rn and their progenies, exposed to hemispherical surfaces in free air, and design of a system to calculate their concentrations

    The sensitivities of LR-115 detectors to 222Rn and 220Rn chains in front of hemispherical surfaces of different radii are calculated by the Monte Carlo method. The optimum radii of hemispherical caps are determined, as a result contributions of the different α-emitter nuclei to the track density are differentiated and non-uniform track distribution is avoided. It is demonstrated that if eight detectors are exposed separately in front of the same number of hemispherical surfaces of different radii, the concentrations of each α emitter in airborne and deposited states can be determined. A passive integrating system to calculate the concentrations of radon, thoron and their progenies in free air is given

  13. A technique for discrimination of radon (222Rn) and thoron (220Rn) in soil-gas using solid state nuclear track detectors

    A technique for discrimination of radon (222Rn) and thoron (220Rn) in soil radon emanometry using SSNTDs has been described. It is based on the large ratio of their half lives and consequent difference in their diffusion lengths. It can be computed that a length of about 25 cm of an air column is adequate to eliminate thoron almost completely while radon is not much affected. Theoretical and experimental curves demonstrating the discrimination of radon and thoron using Kodak Pathe LR-115 cellulose nitrate films have been presented. The design of a sonde for the estimation of radon as well as thoron in soil gas for uranium coefficient of radon in air at room temperature has been determined experimentally. (author)

  14. Study of radon exhalation and emanation rates from fly ash samples

    Fly ash, a by-product of burnt coal is technologically important material being used for manufacturing of bricks, sheets, cement, land filling etc. The increased interest in measuring radon exhalation and emanation rates in fly ash samples is due to its health hazards and environmental pollution and the same have been measured to assess the radiological impact of radon emanated from fly ash disposal sites. Samples of fly ash from different thermal power stations in northern India and National Council for Cement and Building Materials (NCB) were collected and analysed for the measurements. For the measurement, alpha sensitive LR-115 type II plastic track detectors were used. Gamma spectrometry and can technique was used for the measurements. The experimental data show that fly ash samples emanate radon in significant amount and this consequently, may result in increased radon levels in dwellings built by using fly ash bricks and excessive radiation exposure to workers residing in the surroundings of fly ash dumping sites. (author)

  15. Assessment of radon-222 concentrations and exhalation rates of rocks and building materials

    One hundred samples were collected from two regions (Bir El-Sid and Wady El-Gemal ) in the Nile Valley. It contain various types of igneous and metamorphic rock samples (acidic dykes, intermediate dykes, basic dykes, serpentinite, metagabbro, menalge). Another set of samples were collected from different regions of Germany. Samples were analyzed and the concentrations in Bq/kg dry weight of radium were determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. A direct method is used to measure 222Rn emanated from the samples, which was analyzed in laboratory using the portable radon monitor Prassi. 222Rn activity concentrations (Bq/m3) were in the range from 36.1± 2 to 96.4 ± 6, 17.8 ± 3 to 73.6 ± 4 and 18.0 ± 2 to 188.1 ± 15 Bq/m3 for samples collected from Bir Elsid, Wadi El-Gemal and samples from Germany respectively. The corresponding values of exhalation rates were from 0.0012 to 0.004, 0.005 to 0.015 and 0.007 to 0.0069 Bq/gs for these areas respectively. (author)

  16. Study of environmental radio activity and radon exhalation rate in some plant samples from some area of Pakur, Jharkhand

    Uranium is a radiotoxic element found in trace quantity in almost all natural occurring materials like soil, rock and sand etc. Radon an inert radioactive gas whose predecessor is Uranium is emitted from soil beneath the house and from building materials. In the present studies, the environmental radioactivity of some plants leaf were measured by using plastic track detectors LR-115, type II, manufactured by Kodak. Track densities measured in terms of track cm-2 day-1, shows a variation from 10.6 track cm-2 day-1 to 42.8 track cm-2 day-1. The technique has been used to determine the Radon exhalation rate of the plants leaf samples collected from the same area. The Radon exhalation rate varies from 0.194 m Bq-1h-1 to 0.435 m Bq-1 h-1. (author)

  17. An Overview on Studying 222Rn Exhalation Rates using Passive Technique Solid-State Nuclear Track Detectors

    Mohamed Abd-Elzaher

    2012-01-01

    Full Text Available Problem statement: Uranium is a radiotoxic element found in trace quantities in alomost all natural accurring materials like soil, rock. Radon an inert radioactive gas whose predecessor in uranium, is emitted from soil beneath the house and from building materials. Accurate knowledge of exhalation rate plays an important role in characterization of the radon source strength in some building materials and soil. It is a useful quantity to compare the relative importance of different sample of building materials and soil. Approach: This study provides an overview of measurements of radon exhalation rates for selected samples in Egypt were carried out using passive measuring techniques were measured by Can Technique using LR-115 type II plastic track detectors. Results: The radon concentration varies from 2.44-29 k Bq m-3 and the corresponding values of surface exhalation rates from 4.16-26.24 Bq m-2. h the radium content 226Ra results in all samples under test in increasing order of magnitude. From the results it can be noticed that The lowest value of 226Ra is 7 Bq kg-1 in Sand sample, while the highest value is 85 Bq kg-1 Ordinary Cement. Conclusion: All the values of radium content in all samples under test were found to be quite lower than the permissible value of 370 Bq kg-1 recommended by Organization for Economic Cooperation and Development."

  18. Study of natural radioactivity and 222Rn exhalation rate in soil samples for the assessment of average effective dose

    The activity concentration of natural radionuclides and 222Rn (Radon) exhalation rate in soil samples were determined using NaI Scintillation detector and Scintillation Radon Monitor. Soil samples were collected from different geological formations of the same area. The average value of 226Ra (Radium) equivalent activity in soil samples of the studied area was 124.9 Bq kg-1. 226Ra equivalent activities was calculated for the analyzed samples to assess the radiation hazards arising due to the use of these soil samples in the construction of dwellings. The 222Rn exhalation rate in the studied area was varied from 6.9 ± 0.2 mBq Kg-1 h-1 to 33.2 ± 2 mBq Kg-1. A positive correlation was obtained between the Ra (Radium) and 222Rn exhalation rate. The overall average annual effective dose in the studied is lower than the world recommended value of 1.0 mSva-1. (author)

  19. Radon exhalation rate from and natural radioactivity in building materials from HLNRAs of Ramsar, lran

    Some areas of Ramsar, a city in northern Iran, have among the highest known background radiation levels in the world. Indoor radon has been recognized as one of the health hazards for people who living in this area. The high background radiation in the 'hot' areas of Ramsar is primarily due to the presence of very high amounts of 226Ra and its decay products, which were brought to the earth's surface by hot springs. Area resident have also used the residue of the hot springs as building materials for construction of houses, which are considered as one of the major sources of this gas in indoor environment in these areas. These building materials have been studied for exhalation rate of radon. The radionuclide content of the building materials were determined. A total of 35 samples were analyzed for 226Ra, 232Th and 40K using a low background High Purity Germanium detector (HPGe). The detector was surrounded by a massive lead shield (10 cm) and coupled to a MCA-Series 100. The system was calibrated with respect to energy and efficiency using reference materials (RGU-1), (RGTh-1) and (RGK-1) that were prepared by International Atomic Energy Agency. The mean activity concentrations of radionuclides in most of them are not very high, and these values are near the normal radiation background. The highest values for the activity concentration of different radionuclides and the exposure rate due to natural radionuclides in this study were observed for the building materials that have made from travertine deposits

  20. Study of radon exhalation rate from different types of surfaces of building and activity of 226Ra in building materials

    Radon exhalation rate from different surfaces of ground floor vary from 0.95 -3.2 mBq.m-2.s-1. The average value in the first floor surface is 1.2 mBq.m-2.s-1 and exhalation from walls vary from 0.752 - 3.85 mBq.m-2s-1 and with a bare surface it is 5.49 mBq.m-2.s-1. The activity of 226Ra in building materials is estimated by using emanometer. The activity of 226Ra is low in sand (4.01 Bq.kg-1) and is high for granite (55 Bq.kg-1), and almost same in concrete and brick. The activity of 226 Ra in building materials is low compared to the global average. (author)

  1. Study of radon exhalation rate from different types of building construction materials using SSNTDds and estimation of lung cancer risk

    Uranium is a radiotoxic element found in trace quantities in almost all naturally occurring materials like soil, rock and sand etc. Building materials are derived from these materials. Radon, an inert radioactive gas whose predecessor is uranium is emitted from soil beneath the house and from building materials. Building materials are the main source of radon inside the dwellings. Because of low level of radon emanation from these materials, long term measurements are needed. Can technique using LR-115 type II solid state nuclear track detector has been employed for the measurement of radon activity and radon exhalation rate from a number of building materials commonly used for construction in Kerala. Radon activity is found to vary from 75.0 to 2212.7 Bqm-3 with an average value of 477.7 Bqm-3, radon exhalation rate from 44.0 to 1337.7 mBqm-2h-1 with an average value of 286.3 mBqm-2h-1 and effective dose equivalent from 5.2 to 157.7 μSv y-1 with an average value 33.7 μSv y-1 for different building construction materials. Radon emanation from granite is found to be maximum while cement brick (hollow) and Kadappa stone give minimum radon emanation. In the case of plastered bricks covered with sealants, radon exhalation is found to increase slightly with acrylic exterior and acrylic emulsion while it decreases with others. (author)

  2. FeNO measured at fixed exhalation flow rate during controlled tidal breathing in children from the age of 2 yr

    Buchvald, F; Bisgaard, H

    2001-01-01

    We have outlined a new method to measure exhaled nitric oxide on-line at fixed flow rate during controlled tidal breathing (FeNO [controlled]) in young children aged 2 yr and older. FeNO(controlled) measures NO on-line during operator-controlled tidal breathing. The operator targets the exhaled...... flow of the child within preset limits of 0.4-0.6 L/s by continuously adjusting an expiratory resistance. FeNO(controlled) is estimated during end exhalation. We have validated this method against the reference method of the single breath on-line (SBOL) maneuvre (FeNO[SBOL]) and compared...

  3. Determining the radon exhalation rate from a gold mine tailings dump by measuring the gamma radiation

    The mining activities taking place in Gauteng province, South Africa have caused millions of tons of rocks to be taken from underground to be milled and processed to extract gold. The uranium bearing tailings are placed in an estimated 250 dumps covering a total area of about 7000 ha. These tailings dumps contain considerable amounts of radium and have therefore been identified as large sources of radon. The size of these dumps make traditional radon exhalation measurements time consuming and it is difficult to get representative measurements for the whole dump. In this work radon exhalation measurements from the non-operational Kloof mine dump have been performed by measuring the gamma radiation from the dump fairly accurately over an area of more than 1 km2. Radon exhalation from the mine dump have been inferred from this by laboratory-based and in-situ gamma measurements. Thirty four soil samples were collected at depths of 30 cm and 50 cm. The weighted average activity concentrations in the soil samples were 308 ± 7 Bq kg−1, 255 ± 5 Bq kg−1 and 18 ± 1 Bq kg−1 for 238U, 40K and 232Th, respectively. The MEDUSA (Multi-Element Detector for Underwater Sediment Activity) γ-ray detection system was used for field measurements. The radium concentrations were then used with soil parameters to obtain the radon flux using different approaches such as the IAEA (International Atomic Energy Agency) formula. Another technique the MEDUSA Laboratory Technique (MELT) was developed to map radon exhalation based on (1) recognising that radon exhalation does not affect 40K and 232Th activity concentrations and (2) that the ratio of the activity concentration of the field (MEDUSA) to the laboratory (HPGe) for 238U and 40K or 238U and 232Th will give a measure of the radon exhalation at a particular location in the dump. The average, normalised radon flux was found to be 0.12 ± 0.02 Bq m−2 s−1 for the mine dump. - Highlights: • Obtain radon flux from a large area

  4. Estimation of radon exhalation rate, natural radioactivity and radiation doses in fly ash samples from NTPC Dadri, (UP) India

    Fly ash produced by coal-burning in thermal power station has become a subject of world wide interest in recent years, because of its diverse uses in building materials such as bricks, sheets, cement and land filling etc. The knowledge of radio nuclides in fly ash plays an important role in health physics. Natural radioactivity and radon exhalation rate in fly ash samples collected from NTPC (National Thermal Power Corporation) Dadri, (UP.) India, have been studied. A high resolution gamma ray spectroscopic system has been used for the measurement of natural radioactivity. The activity concentration of natural radionuclides radium (226Ra), thorium (232Th) and potassium (40K) were measured and radiological parameters were calculated. Radium concentration was found to vary from (81.01 ± 3.25) to (177.33 ±10.00) Bq kg-1. Activity concentration of thorium was found to vary from (111.57 ± 3.21) to (178.50 ± 3.96) Bq kg-1. Potassium activity was not significant in some samples, whereas, some other samples have shown potassium activity vary from (365.98 ± 4.85) to (495.95 ± 6.23) Bq kg-1. Radon exhalation rates in these samples were also calculated by 'Sealed Can technique' using LR-115 type II detectors and found to vary from (80 ± 9) to (243 ± 16) mBqm-2h-1 with an average value (155 ± 13) mBqm-2h-1. This study also presents the results of estimation of effective dose equivalent from exhalation rate, radium equivalent, absorbed gamma dose rates, external annual effective dose rate and values of external hazard index for the fly ash samples. (author)

  5. Natural radioactivity, radon exhalation rates and indoor radon concentration of some granite samples used as construction material in Turkey

    It is very important to determine the levels of the natural radioactivity in construction materials and radon exhalation rate from these materials for assessing potential exposure risks for the residents. The present study deals with 22 different granite samples employed as decoration stones in constructions in Turkey. The natural radioactivity in granite samples was measured by gamma ray spectrometry with an HPGe detector. The activity concentrations of 226Ra, 232Th and 40K were found to be in the range of 10-187, 16-354 and 104-1630 Bq kg-1, respectively. The radon surface exhalation rate and the radon mass exhalation rate estimated from the measured values of 226Ra content and material properties varied from 1.3 to 24.8 Bq m-2 h-1 with a mean of 10.5±1.5 Bq m-2 h-1 and 0.03-0.64 Bq kg-1 h-1 with a mean of 0.27±0.04 Bq kg-1 h-1, respectively. Radon concentrations in the room caused from granite samples estimated using a mass balance equation varied from 23 to 461 Bq m-3 with a mean of 196±27 Bq m-3. Also the gamma index (Iγ), external indoor annual effective dose (Eγ) and annual effective dose due to the indoor radon exposure (ERn) were estimated as the average value of 1.1±0.1, 0.16±0.02 mSv and 5.0±0.7 mSv, respectively, for the granite samples. (authors)

  6. Study on radon exhalation rate from Indian granite samples using nuclear track detector based passive method as well as dynamic method

    Building materials being important source of indoor radon concentrations, radon exhalation rate from building material samples had gained wide attention over decades. Among them some granite varieties were reported to show high radon exhalation rate. Eight different varieties of Indian granite samples were analyzed for radon surface exhalation rate using active as well as passive methods. Sealed-can technique with LR115 nuclear track detector was used in the passive method and Scintillation based SRM online radon monitor was used in the active dynamic method. The radon exhalation rate from the tiles measured using SSNTD based passive method ranged from 0.016 ± 0.003 Bq m-2h-1 to 3.5 ± 0.5 Bqm-2h-1 with an average value of 0.899 Bq m-2h-1, whereas deviations were observed in the case of dynamic method results. The details of the study are reported. A comparative analysis on passive and dynamic method of exhalation rate measurement also has been carried out looking into thoron interference and radon leakage issues from closed chambers (author)

  7. Field GE gamma spectrometry for on site measurements of some parameters characterizing radon-222 exhalation rates from soils and covers

    We describe a new method based on differential gamma spectrometry for on site determination of some of the parameters which are relevant for the production of radon 222 in soil gas and its transfer from soil to indoor and outdoor atmospheres. This method is investigated in the context of a 3-year Slovenian-French cooperation programme, the PROTEUS project. We are currently using a germanium detector of 100 cm3. The height of the 20 deg. C collimated detector above the soil surface is from 1.5 to 3 m when using a tripod. This arrangement provides results which are representative of soil areas ranging from 1 to 4 square metres. Routine measurements would require larger detector volumes. The main objective is to provide technology and methodology for an efficient mapping of zones with potential for being the source of a high level of indoor radon, eliminating the need for soil sampling followed by laboratory analysis. The feasibility of an airborne mapping laboratory flying at low altitude will be investigated. Another objective is the rapid measurement of radon profiles across covers used to reduce exhalation rates from the surface of a pile of tailings, with characterisation of the influence of humidity content of the top layer. Airborne survey would allow for measuring exhalations from surfaces of slurries not otherwise accessible. (author)

  8. Prediction of 222 Rn exhalation rates from phosphogypsum based stacks. Part II: preliminary numerical results

    The first part of this paper proposes a steady-state 2-D model for 222 Rn transport in phosphogypsum stacks. In this second part, the dimensionless model equations are solved numerically with the help of an existing finite-volume simulator that has been successfully used to solve heat and mass transfer problems in porous media. As a test case, a rectangular shaped stack is considered in order to verify the ability of the proposed parametric approach to account for concurrent effects on the 222 Rn exhalation into the local atmosphere. Air flow is supposed to be strictly buoyancy driven and the ground is assumed to be impermeable to 222 Rn and at a higher temperature under the stack base. Dimensionless controlling parameters are set to representative values and results are presented for Grashof number in the range 106 ≤Gr≤ 108, corresponding to very small to small temperature differences between incoming air and ground underneath the stack base. For the particular set of parameters and inasmuch as Gr increases, streamlines presented basically the same pattern while internal isotherms and iso concentration lines remained almost unchanged. Total average Sherwood number proved to be rather insensitive to Gr while total average Nusselt increased slightly with Gr. (author)

  9. Exposure to exhaled air from a sick occupant in a two-bed hospital room with mixing ventilation: effect of distance from sick occupant and air change rate

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Georgiev, Emanuil

    2011-01-01

    Full-scale measurements were performed in a climate chamber set as a two-bed hospital room, ventilated at 3, 6 and 12 h-1. Air temperature was kept constant at 22 °C. Two breathing thermal manikins were used: a sick patient lying on one side in one bed and a doctor. A thermal dummy mimicked...... an exposed patient lying in the second bed. The doctor stood 0.55 m or 1.1 m facing the sick patient. The breathing mode of the “sick patient” was: exhalation mouth/inhalation nose. Tracer gas (R-134a) was mixed with the exhaled air. Important finding of this study is that airflow distribution...... and interaction in rooms, distance between the source and recipient, etc. may play more important role for the exposure to the air exhaled by the sick patient than the ventilation rate. Increase in ventilation may affect adversely the exposure to exhaled air and thus enhance the risk from airborne cross infection....

  10. 222Rn and 220Rn concentrations measured in various natural honey samples by using nuclear track detectors and resulting radiation doses to the members of the rural populations in Morocco

    Radon (222Rn) and thoron (220Rn) concentrations were measured in sixteen natural honey material samples collected from different regions in Morocco by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). The concentrations of these radionuclides were also measured in nectar solutions corresponding to the studied honey samples. The measured concentrations of 222Rn and 220Rn in honey samples ranged from (2.3 ± 0.2) to (8.1 ± 0.6) Bq.l-1 and (1.8 ± 0.1) to (3.9 ± 0.3) Bq.l-1, respectively. Committed equivalent doses due to annual intakes of 222Rn were evaluated in the human gastrointestinal tract compartments of adult members of the Moroccan populations from the ingestion of studied honey samples. The influence of the target tissue mass and activities due to 222Rn on the annual committed equivalent doses in the compartments of the human gastrointestinal tract was investigated. (authors)

  11. Exposure to Exhaled Air from a Sick Occupant in a Two-Bed Hospital Room with Mixing Ventilation: Effect of Posture of Doctor and Air Change Rate

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Barova, Mariya

    2013-01-01

    Full-scale measurements were performed in a climate chamber set as a two-bed hospital room, ventilated at 3, 6 and 12 ACH with overhead mixing ventilation. Air temperature was kept constant at 22 °C. Two breathing thermal manikins were used to mimic a sick patient lying on one side in one...... the ventilation rate itself. Furthermore, increase in ventilation may affect adversely the exposure to exhaled air and thus enhance the risk from airborne cross infection....

  12. Extensive radioactive characterization of a phosphogypsum stack in SW Spain: {sup 226}Ra, {sup 238}U, {sup 210}Po concentrations and {sup 222}Rn exhalation rate

    Abril, Jose-Maria, E-mail: jmabril@us.es [Dpto. Fisica Aplicada I, Universidad de Sevilla, EUITA, Ctra Utrera Km 1, 41013 Seville (Spain); Garcia-Tenorio, Rafael, E-mail: gtenorio@us.es [Dpto. Fisica Aplicada II, Universidad de Sevilla, ETSA, Avda. Reina Mercedes s/n, 41012 Seville (Spain); Manjon, Guillermo, E-mail: manjon@us.es [Dpto. Fisica Aplicada II, Universidad de Sevilla, ETSA, Avda. Reina Mercedes s/n, 41012 Seville (Spain)

    2009-05-30

    Phosphogypsum (PG) is a by-product of the phosphate fertilizer industries that contains relatively high concentrations of uranium series radionuclides. The US-EPA regulates the agriculture use of PG, attending to its {sup 226}Ra content and to the {sup 222}Rn exhalation rate from inactive stacks. Measurements of {sup 222}Rn exhalation rates in PG stacks typically show a large and still poorly understood spatial and temporal variability, and the published data are scarce. This work studies an inactive PG stack in SW Spain of about 0.5 km{sup 2} from where PG can be extracted for agriculture uses, and an agriculture soil 75 km apart, being representative of the farms to be amended with PG. Activity concentrations of {sup 226}Ra, {sup 238}U and {sup 210}Po have been measured in 30 PG samples (0-90 cm horizon) allowing for the construction of maps with spatial distributions in the PG stack and for the characterization of the associated PG inputs to agriculture soils. Averaged {sup 226}Ra concentrations for the stack were 730 {+-} 60 Bq kg{sup -1} (d.w.), over the US-EPA limit of 370 Bq kg{sup -1}. {sup 222}Rn exhalation rate has been measured by the charcoal canister method in 49 sampling points with 3 canisters per sampling point. Values in PG stack were under the US-EPA limit of 2600 Bq m{sup -2} h{sup -1}, but they were one order of magnitude higher than those found in the agriculture soil. Variability in radon emissions has been studied at different spatial scales. Radon exhalation rates were correlated with {sup 226}Ra concentrations and daily potential evapotranspiration (ETo). They increased with ETo in agriculture soils, but showed an opposite behaviour in the PG stack.

  13. The exhalant jet of mussels Mytilus edulis

    Riisgard, Hans Ulrik; Jørgensen, Bo Hoffmann; Lundgreen, Kim;

    2011-01-01

    The exhalant jet flow of mussels in conjunction with currents and/or other mussels may strongly influence the mussels' grazing impact. Literature values of mussel exhalant jet velocity vary considerably and the detailed fluid mechanics of the near-mussel flow generated by the exhalant jet has...... shell lengths. Here, we present results of a detailed study of fully open mussels Mytilus edulis in terms of filtration rate, exhalant siphon aperture area, jet velocity, gill area and body dry weight, all as a function of shell length (mean +/- SD) over the range 16.0 +/- 0.4 to 82.6 +/- 2.9 mm......, with the corresponding scaling laws also presented. The exhalant jet velocity was determined by 3 methods: (1) measured clearance rate divided by exhalant aperture area, (2) manual particle tracking velocimetry (PTV) using video-microscope recordings, and (3) particle image velocimetry (PIV). The latter provides...

  14. Study of radon exhalation rates using solid state nuclear track detectors in stone mining area of Aravali range in Pali region, district Faridabad

    It is well established that indoor radon-thoron and daughters are the largest contributor to total radiation dose received by populations. They account for more than 50% of the total dose and the radiation exposure beyond permissible levels can lead to deleterious effects on health. This fact necessitates extensive studies of natural radioactivity levels in the stone mining area of Aravali range in Faridabad. The stone mining area of Aravali Range in Pali, District Faridabad bears significant geological features. Radon exhalation from ground plays an important role in enhanced indoor radon levels and can pose grave health hazards to the workers and the residents. Exhalation rates (mass and surface) from stone samples of the area have been studied using LR-115, Type II nuclear track detectors. The mass and surface exhalation rates from crushed stone samples, also called stone dust varied in the range 3.41-9.11 mBq kg-1 h-1 and 75.9-202.7 mBq m-2 h-1, respectively. The study has revealed substantial presence of radionuclides in the samples collected from the mining area. (author)

  15. Radium activity and radon exhalation rates from phosphate ores using CR-39 on-line with an electronic radon gas analyzer 'Alpha GUARD'

    Saad, A.F. [Physics Department, Faculty of Science, Zagazig University, Zagazig (Egypt)], E-mail: abdallahsaad@hotmail.com

    2008-08-15

    Nuclear track detectors (NTDs) have seen a major expansion in application to general physical and geological problems reflecting its advances in understanding the exhalation dependence of radon as well as radon and radium concentration distributions in the earth's crust. However, considerable uncertainties still persist, in particular, concerning the detection efficiency of track detectors which are not calibrated precisely to a standard method or an active detector of a unique efficiency. In this investigation, CR-39 NTDs and an electronic radon gas analyzer 'Alpha GUARD' were used for the measurement of radon exhalation rate and radium concentration in phosphate samples collected from two different mines of El-Sobaeya and El-Suez, Egypt. The phosphate sample was loaded into an emanation container (Genitron Instruments GmbH) equipped with a PC-based radon gas analyzer. The CR-39 track detectors were mounted inside a diffusion cup used simultaneously with the Alpha GUARD radon gas analyzer. Radium activity in phosphate samples was found to vary from 1.8 to 361.3kBqkg{sup -1}. The radon exhalation rates in these samples were found to vary from 0.020 (0.003) to 4.125Bqm{sup -2}h{sup -1}(0.658Bqkg{sup -1}h{sup -1})

  16. Study on radon exhalation rate in sedimentary and igneous rocks used as building materials in Tiruchirappalli district, Tamil Nadu, India

    Tiruchirappalli district is naturally endowed with rich building material resources which are also used in neighboring districts. Hence, measurement of radon level in these building materials is important to assess its impact on human health. The present study was undertaken to measure the activity concentration of radon in 8 sedimentary rock (stone rock) quarries and 6 igneous rocks (granite) quarries. Sealed Can Technique using Solid State Nuclear Track Detector was employed for the measurement of radon emanation. The activity concentration of radon in sedimentary rocks ranged from 18.8 ± 0.3 Bqm-3 to 56.0± 4.8 Bqm-3 with the mean concentration of 29.47 ± 12.6 Bqm-3. However, radon concentrations in igneous rocks are distinctly higher and ranged from 47.8 ± 4.0 Bqm-3 to 570.0 ± 95.0 Bqm-3 with the mean value of 273.5 ± 167.7 Bqm-3. The mean radium concentration (CRa) was recorded in both sedimentary (2.13 ± 0.94 Bqkg-1) and igneous rocks (20.4 ± 12.59 Bqkg-1) were well within the limit prescribed for dwellings (370 Bq kg-1). The mass and surface exhalation rates were also calculated in all the rock samples. The study concludes that the sedimentary rocks and the igneous rocks analyzed were radiologically safe when used as building materials expect the granite rock from Narthamalai (S13) which registers a higher mean radon activity of 570.0 ± 95.0 Bq m-3. (author)

  17. Health assessment of natural radioactivity and radon exhalation rate in granites used as building materials in Lebanon

    Measurements of specific activities (Bq kg-1) of gamma-emissions from radioactive nuclides, 238U, 226Ra, 214Bi, 232Th, 212Pb and 40K, contained in 28 granite types, used as building materials in indoors in Lebanon, were performed on the powdered granites. The concentration of the nuclides, 226Ra, 232Th and 40K, in the granites varied from below detection level (BDL) to 494 Bq kg-1, BDL to 157.2 Bq kg-1 and BDL to 1776 Bq kg-1, respectively. 226Ra concentration equivalents, CRaeq, were obtained and ranged between 37 and 591 Bq kg-1, with certain values above the allowed limit of 370 Bq kg-1. Calculated annual gamma-absorbed dose in air, DaR, varied from 17.7 to 274.5 (nGy h-1). Annual effective dose, E (mSv y-1), of gamma radiations related to the studied granites and absorbed by the inhabitants was evaluated. E (mSv y-1) ranged from 0.09 to 1.35 mSv y-1. Some granite types produced E above the allowed limit of 1 mSv y-1 set by ICRP. Values of 222Rn mass exhalation rate, EM (mBq kg-1h-1), in granite powder were obtained using the CR-39 detector technique. Diffusion factors, f, in 23 granite types were calculated with f ranging between (0.1±0.02)x10-2 and (6.6±1.01)x10-2. (authors)

  18. LR-115 detector response to {sup 222}Rn, {sup 220}Rn and their progenies, exposed to hemispherical surfaces in free air, and design of a system to calculate their concentrations

    Palacios, D. [Universidad Simon Bolivar, P.O. 89000, Caracas (Venezuela)], E-mail: palacios@usb.ve; Palacios, F. [Universidad de Oriente, Santiago de Cuba (Cuba); Sajo-Bohus, L.; Barros, H.; Greaves, E.D. [Universidad Simon Bolivar, P.O. 89000, Caracas (Venezuela)

    2008-08-15

    The sensitivities of LR-115 detectors to {sup 222}Rn and {sup 220}Rn chains in front of hemispherical surfaces of different radii are calculated by the Monte Carlo method. The optimum radii of hemispherical caps are determined, as a result contributions of the different {alpha}-emitter nuclei to the track density are differentiated and non-uniform track distribution is avoided. It is demonstrated that if eight detectors are exposed separately in front of the same number of hemispherical surfaces of different radii, the concentrations of each {alpha} emitter in airborne and deposited states can be determined. A passive integrating system to calculate the concentrations of radon, thoron and their progenies in free air is given.

  19. Radon exhalation rates corrected for leakage and back diffusion – Evaluation of radon chambers and radon sources with application to ceramic tile

    M. Abo-Elmagd

    2014-10-01

    Full Text Available The natural radon decay, leakage and back diffusion are the main removal processes of radon from its container. Ignoring these processes leads to underestimate the measured value of radon related parameters like exhalation rate and radium content. This work is aimed to evaluate two different radon chambers through determining their leakage rate λv and evaluation of radon source by determine its back diffusion rate λb inside the evaluated radon chambers as well as a small sealed cup. Two different methods are adapted for measuring both the leakage rate and the back diffusion rate. The leakage rate can be determined from the initial slope of the radon decay curve or from the exponential fitting of the whole decay curve. This can be achieved if a continuous monitoring of radon concentration inside the chamber is available. Also, the back diffusion rate is measured by sealing the radon source in the chamber and used the initial slope of the buildup curve to determine λb and therefore the exhalation rate of the source. This method was compared with simple equation for λb based on the ratio of the source to the chamber volume. The obtained results are applied to ceramic tile as an important radon source in homes. The measurement is targeted the ceramic glaze before and after firing as well as the obtained tile after adhere the glaze on the tile main body. Also, six different tile brands from Egyptian market are subjected to the study for comparison.

  20. Estimation of soil exhalation rate and indoor radon concentration in air using RAD7 for health risk assessment in Hisar district, Haryana

    For the health risk assessment of the residents because of the exposure to indoor radon concentration in the dwellings an active technique using RAD7 (an electronic radon detector) has been employed in the 50 dwellings in the studied area of Hisar district of Haryana, India. Also the average annual effective dose due to radon gas has been calculated. The estimation of radon gas exhalation rates in the 50 soil samples collected from the studied area has also been carried out by sealed Can Technique using LR-115 solid state nuclear track detectors (SSNTDs). The measured surface exhalation rates in the soil samples vary from 189.74 to 285.99 mBq m-2h-1 and mass exhalation rates vary from 8.61 to 11.16 mBq kg-1h-1. The measured indoor radon values in the study area varies from 51.09 to 324.23 Bq m-3 with an average value of 191.80 Bq m-3 which is well within the recommended action level 200-300 Bq m-3 (ICRP, 2009) in about 80% of the samples and is slightly above 300 Bq m-3 in only about 20% of the samples. The indoor radon values obtained in the present investigation are more than the world average of 40 Bq m-3 The annual average dose received by the residents of the study area varies from 1.29 mSv to 8.17 mSv with an average value of 4.83 mSv which was calculated using parameters introduced in report by UNSCEAR (2000) and these values are within the recommended safe limit of 3 mSv to 10 mSv. These values suggest that there is no significance threat to the human beings due to the presence of natural radon in the dwellings. (author)

  1. A preliminary Investigation of 222Rn and 220Rn levels in non-uranium mines in China%我国非铀矿山222Rn和220Rn水平初步调查研究

    尚兵; 崔宏星; 武云云; 张庆召; 苏旭

    2008-01-01

    Objective To measure levels of 222Rn and 220Rn in typical non-uranium mines, China, and to estimate dose from the occupational radon exposure in the miners. Methods Using typical sampling scheme,44 mines were selectcd in 12 provinces, which can be classified into 4 categories and 17 types of mines. The radon-thoron discriminative detectors were used to measure 222Rn and 220Rn concentrations in mines. Result The concentration of 222Rn or 220Rn was log-normally distributed. The arithmetic mean (AM) concentration and geometric mean (GM) concentration of 222Rn and 220Rn in 25 metal mines (n=147) were estimated to be (1211±2359) Bq/m3(AM) and (311±5.5) Bq/m3(GM), and (269±700) Bq/m3(AM) and (71±4.4)Bq/m3(GM), respectively. The mean concentrations of 222Rn and 220Rn in 18 non-metal mines (n=118) were (98±207) Bq/m3(AM) and(55±2.5) Bq/m3(GM), and (60±76) Bq/m3(AM) and (38±2.4)Bq/m3(GM),respectively. In total, we measured 222 Rn concentration in 44 underground mines, 6 of them, accounted for 15%, with the mean radon concentration exceeding 1000 Bqm-3 (limit of workplace in China). Approximately 7% of radon concentration in mines measured were higher than 3700 Bq/m3(current limit in uranium mine in China), some points even exceeded 10 000 Bq/m3. Based on this typical measurements, the equilibrium factor for 222Rn was estimated to be 0.33±0.15 in underground mines and 0.47±0.18 in nearby houses. Equilibrium factor for 222Rn ranged from 0.001 to 0.032. Using the data obtained in this typical survey, the average annual effective dose of underground miners exposed to radon and thoron was estimated to be 8.15 mSv/a. Conclusions High levels of 222Rn exists in metal mines, such as copper, tin, lead and zinc, gold, and aluminum mines among others. More study and administrative measures are needed to address the radiation protection of workers occupationally exposed to high radon in mines.%目的 测量非铀矿山222Rn、220Rn水平,了解我国矿山氡超标比

  2. Attempts on determination of radon exhalation rate from a waste-dump of Bogdanka coal mine with use of the Picorad detectors

    The Bogdanka coal mine is located in the Pojezierze Leczynsko-Wlodawskie district in the vicinity of the Poleski National Park. From the beginning of mining activity, i.e. for the last 20 years, waste rock has been deposited close by. It consists mainly of clumps (about 88%) of a few centimeters grain-size, while sandstones, siderite and mudstones form the rest. A storage yard, filled to about 30%, covers an area of 83 ha and is partly cultivated. It is well known that deposited waste rocks of coal mines may be a source of radon. The emission rate of this element from a spoil dump depends on many factors, so direct measurements of the exhalation rate are the most reliable. Passive detectors containing activated carbon (Picorad, Niton-Canberra-Packard), designed for the detection of stable concentrations of indoor radon were used. An application of these detectors in open areas may produce errors associated with the higher humidity and variable concentrations of exhaled radon. The radioactivity of radon and its daughters was determined using a liquid scintillation spectrometer (Quantulus, Wallac-Perkin-Elmer). Measurements were made at several points on the spoil dump, including where waste was most recently deposited and cultivated sites. A calibration of the detectors with various radon concentrations and humidity levels was performed in a radon chamber at the Central Mining Institute. (author)

  3. Estimation of dose contribution from 226Ra, 232Th and 40K radon exhalation rates in soil samples from Shivalik foot hills in India.

    Chauhan, R P; Chauhan, Pooja; Pundir, Anil; Kamboj, Sunil; Bansal, Vakul; Saini, R S

    2014-01-01

    The concentration of radium, thorium and potassium and radon exhalation rates in soil samples collected from Shivalik foot hills in the states of Haryana and Himachal Pradesh (India) were experimentally measured. A high-resolution gamma-ray spectroscopic system was used for the measurement of natural radioactivity ((226)Ra, (232)Th and (40)K) at Inter-University Accelerator Center, New Delhi, using a coaxial n-type high-purity germanium detector (EG&G, ORTEC, Oak Ridge, USA). The mass exhalation rates (EM) of radon in soil samples from the study area measured by 'sealed canister technique' using LR-115 type II track detectors varied from 50±1 to 143±6 mBqkg(-1) h(-1). The activity concentrations of (226)Ra, (232)Th and (40)K in various soil samples of the study area varied from 31±1.3 to 63±4.6, 53±1.8 to 78±2.6 and 472±4.8 to 630±7.0 Bq kg(-1) respectively. The results indicated some higher levels of radioactivity in Lal Dhang peak area of the hills compared with other locations under study. PMID:23893776

  4. The influence of the nature of soil and plant and pollution on the 238U, 232Th, 222Rn and 220Rn concentrations in various natural honey samples using nuclear track detectors: Impact on the adult consumers

    M A Misdaq; A Mortassim

    2009-11-01

    238U and 232Th concentrations as well as 222Rn and 220Rn -activities per unit volume were measured in various natural honey samples collected from different regions in Morocco using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). These radionuclides were also measured in soils, plant flowers and nectar solutions corresponding to the honey samples studied. In addition, these radionuclides were measured in different imported honey samples. The measured 238U, 232Th, 222Rn and 220Rn concentrations ranged from (1.5 ± 0.1) mBq kg-1 to (10.6 ± 0.6) mBq kg-1, (1.1 ± 0.1) mBq kg-1 to (4.2 ± 0.2) mBq kg-1 , (1.5 ± 0.1) Bq kg-1 to (10.6 ± 0.6) Bq kg-1 and (1.1 ± 0.1) Bq kg-1 to (4.2 ± 0.2) Bq kg-1 for the honey samples studied, respectively. Annual 238U, 232Th and 222Rn intakes by Moroccan adults from the consumption of honey were assessed. The influence of the nature of soil and plant on the 238U and 232Th contents of the studied honey samples was investigated. These measurements were completed by an investigation of the 238U and 232 Th transfer between soils and plant flowers and that between plant flowers and honey, and also by the investigation of the influence of pollution due to different material dusts on 238U, 232Th and 222Rn in the honey samples studied. Committed equivalent doses due to the annual intake of 238U, 232Th and 222Rn were evaluated in the organs of adult members of the Moroccan rural population from the ingestion of the honey samples. The maximum total committed effective dose due to 238U, 232Th and 222Rn from the ingestion of natural honey by the Moroccan rural population was found to be equal to 0.64 Sv y-1 .

  5. Study on dependence of breakthrough time on flow rate of the carrier, gas in 229Rn adsorber bed

    Activated charcoal is a well-known adsorber of 222Rn and 220Rn gasses and its uses in mitigation of 222Rn and 220Rn in works places were reported earlier. A mitigation factor of >105 was achieved easily for 220Rn using cylindrical columns filled with activated charcoal. These studies have also reported the 222Rn breakthrough curves, breakthrough time and radon adsorption coefficient (K) for charcoal. In this paper we evaluate the effect of flow rate of the carrier gas on breakthrough time and the mitigation factor. This information is very useful in designing 220Rn migitation systems for the actual use in workplaces. The variations in breakthrough time and adsorption coefficient (K) with the flow-rate of the radon laden air in the charcoal adsorber bed were studied in detail. It was observed that the break through time was higher for lower flow rates and lower for higher flow rates. The details are presented and discussed in this paper. (author)

  6. Radon exhalation from building materials

    The new Israeli standard 5098 limits the total radiation dose of the general public from building materials to 0.45 mSv / year. A building material is accepted if it satisfies a criterion depending on the activity concentration of the natural radionuclides 226Ra, 232Th, 40K and on the Radon (222Rn) exhalation rate. As compared with existing standards, which consider only the gamma dose, this standard includes the Radon contribution allowing thereby to rigorously control the radiation dose from this practice to the general public in Israel. While the radionuclide activity may be measured via standard HPGe gamma spectroscopy, the measurement of the Radon exhalation rate is not yet standardized. According to Standard 5098 the Ministry of the Environment is responsible to recommend the optimal technique

  7. Measurement of natural radioactivity and radon exhalation rate in fly ash samples from a thermal power plant and estimation of radiation doses

    Fly ash produced by coal-burning in thermal power station has become a subject of world wide interest in recent years because of its diverse uses in construction activities and considerable economic and environmental importance. Fly ash is used in the production of bricks, sheets, cement and also in land filling etc. Indian coals used in thermal power plants are found to have high ash contents, resulting in the production of large amount of fly ash. Coal contains radionuclides including uranium (the source of inert gas radon), Th and K. Thus coal combustion results in enhanced concentration of natural radionuclides 226Ra, 232Th and 40K. Since these radionuclides concentration in fly ash plays an important role in health physics it is important to measure radionuclides concentration in fly ash. In the present work enhanced radioactivity and radon exhalation rate from fly ash samples collected from a thermal power plant of NTPC (National Thermal Power Corporation), Dadri (U.P.) India, have been measured. A high resolution gamma ray spectroscopic system has been used for the measurement of natural radioactivity (226Ra, 232Th and 40K). Gamma spectrometric measurements were carried out at Inter-University Accelerator Centre, New Delhi using a coaxial n-type HPGe detector (EG and G, ORTEC, Oak Ridge, USA). Activity concentration of 226Ra varies from 81.8 ± 2.2 to 177.3 ± 10.0 Bq kg−1 with an average value of 118.6 ± 7.4 Bq kg−1 and of 232Th from 111.6 ± 3.2 to 178.5 ± 3.9 Bq kg−1 with an average value of 147.0 ± 3.4 Bq kg−1. 40K activity was found to be below detection limit in some samples while other samples have shown potassium activity to vary from 365.9 ± 4.8 to 495.9 ± 6.2 Bq kg−1 with an average value of 352.0 ± 4.5 Bq kg−1. Surface radon exhalation rates (EA) and Mass exhalation rates (EM) in these samples were measured by “Sealed can technique” using LR-115 type II track detectors. EA is found to vary from 80.1 ± 9.3 to 242.7 ± 16.3 m

  8. Postprandial changes in the exhalation of radon from the environment

    The exhalation of radon originally inhaled from the home environment and dissolved in body fluids and tissues has been studied serially for periods of several hours in six persons. The observation of a pronounced postprandial peak in the rate of exhalation of radon shows that the similar peak observed in the exhalation of radon produced from radium in vivo results from the flushing of a reservoir in soft tissue and not from a change in the fraction lost from bone

  9. Inhaling to mitigate exhaled bioaerosols

    Edwards, David A.; Man, Jonathan C.; Brand, Peter; Katstra, Jeffrey P.; Sommerer, K.; Stone, Howard A.; Nardell, Edward; Scheuch, Gerhard

    2004-01-01

    Humans commonly exhale aerosols comprised of small droplets of airway-lining fluid during normal breathing. These “exhaled bioaerosols” may carry airborne pathogens and thereby magnify the spread of certain infectious diseases, such as influenza, tuberculosis, and severe acute respiratory syndrome. We hypothesize that, by altering lung airway surface properties through an inhaled nontoxic aerosol, we might substantially diminish the number of exhaled bioaerosol droplets and thereby provide a ...

  10. Radon exhalation from building materials used in Libya

    Radon exhalation rates have been determined for various different samples of domestic and imported building materials available in the Libyan market for home construction and interior decoration. Radon exhalation rates were measured by the sealed-can technique based on CR-39 nuclear track detectors (NTDs). The results show that radon exhalation rates from some imported building materials used as foundations and for decoration are extremely high, and these samples are the main sources of indoor radon emanation. Radium contents and annual effective doses have also been estimated. - Highlights: • Radon exhalation was measured in building materials (BM) by the can technique. • The results are mostly within the worldwide range of values found in BM samples. • Two high values of radon concentration have been observed from granite and marble. • No significant risk to the human beings due to the presence of radon in the homes

  11. Radon exhalation from building materials for decorative use.

    Chen, Jing; Rahman, Naureen M; Abu Atiya, Ibrahim

    2010-04-01

    Long-term exposure to radon increases the risk of developing lung cancer. There is considerable public concern about radon exhalation from building materials and the contribution to indoor radon levels. To address this concern, radon exhalation rates were determined for 53 different samples of drywall, tile and granite available on the Canadian market for interior home decoration. The radon exhalation rates ranged from non-detectable to 312 Bq m(-2) d(-1). Slate tiles and granite slabs had relatively higher radon exhalation rates than other decorative materials, such as ceramic or porcelain tiles. The average radon exhalation rates were 30 Bq m(-2) d(-1) for slate tiles and 42 Bq m(-2) d(-1) for granite slabs of various types and origins. Analysis showed that even if an entire floor was covered with a material having a radon exhalation rate of 300 Bq m(-2) d(-1), it would contribute only 18 Bq m(-3) to a tightly sealed house with an air exchange rate of 0.3 per hour. Generally speaking, building materials used in home decoration make no significant contribution to indoor radon for a house with adequate air exchange. PMID:20167403

  12. Radon exhalation from building materials for decorative use

    Long-term exposure to radon increases the risk of developing lung cancer. There is considerable public concern about radon exhalation from building materials and the contribution to indoor radon levels. To address this concern, radon exhalation rates were determined for 53 different samples of drywall, tile and granite available on the Canadian market for interior home decoration. The radon exhalation rates ranged from non-detectable to 312 Bq m-2 d-1. Slate tiles and granite slabs had relatively higher radon exhalation rates than other decorative materials, such as ceramic or porcelain tiles. The average radon exhalation rates were 30 Bq m-2 d-1 for slate tiles and 42 Bq m-2 d-1 for granite slabs of various types and origins. Analysis showed that even if an entire floor was covered with a material having a radon exhalation rate of 300 Bq m-2 d-1, it would contribute only 18 Bq m-3 to a tightly sealed house with an air exchange rate of 0.3 per hour. Generally speaking, building materials used in home decoration make no significant contribution to indoor radon for a house with adequate air exchange.

  13. Measurement and estimation of inhalation dose rates from radon, thoron and its progenies in indoor environment

    Measurement of 222Rn and 220Rn were carried out in more than 2000 houses of different types of construction in 45 locations around several parts of the country using Solid State Nuclear Track Detector (SSNTD) based dosimeter developed at the Bhabha Atomic Research Centre (BARC). This comprises of two cylindrical cups designed for optimum registration of tracks. Three detector films are used for the measurements; two in the cup modes for 222Rn and 220Rn gas estimation and one in bare mode for their progeny measurements. Detector film used is LR-115 Type-II pelliculable, of 12 μm thick cellulose nitrate. Measured geometric mean (GM) of 222Rn levels in these dwellings varied from 6.3 to 147.3 Bq/m3 with an overall GM of 23.9 Bq/m3 (GSD 1.94); while that of 220Rn varied from 5.1 to 42.8 Bq/m3 with an overall geometric mean of 14.7 Bq/m3 (GSD 1.77). Estimated total inhalation dose rates using UNSCEAR dose conversion factors, varied from 0.30 to 4.44 mSv/y with a GM of 0.97 mSv/y (GSD 1.82). It is observed that between 60 to 70% of the total inhalation dose is due to 222Rn and its progeny; while that of 222Rn and its progeny contribute to between 30-40%. (author)

  14. Radon exhalation from some finishing materials frequently used in Syria

    Building materials are one of the main radon sources in dwellings. Therefore, the determination of radon exhalation from these materials will help in prediction the existence of dwelling with potential radon risk. Ceramic tiles and marble samples were collected from Syrian local market. The correlation between radon exhalation from these materials and radium-226 content was studied. Results showed that there is no clear relation between radium content and radon exhalation rate, and the exhalation of radon did not exceed the permissible limits of American Environment Protection Agency (EPA). In addition, the additional annual dose from radon and gamma of the natural radioactivity in ceramic and marble when used as finishing materials in houses was also estimated and found to be not exceeding 20 μSv and 35 μSv from radon and gamma respectively.

  15. Radon exhalation from and diffusion in concrete

    Cylindrical test pieces of concrete are used for measurements of 222Rn exhalation rates. Except one flat end surface of a test piece, other parts of its exteriority are covered with sealant. Radon atoms can escape only through its end surface from the interior into the outside air. This treatment makes the radon transport in the concrete one dimensional phenomena. The piece is put in an airtight container. Time variations of radon concentrations in the air of the container are measured with a plane multiwire-electrode ionization chamber. From this result, the radon areal exhalation rate is deduced for the piece. Exhalation rates are measured for four pieces with different length. Then, the diffusion coefficient is obtained for radon in the concrete as (5.0 ± 1.0) x 10-8m2s-1 (a one-block method). A two-block method has been invented to obtain simultaneously values of three parameters: diffusion coefficient, porosity of concrete, and radon production rate in the pore air in the concrete. Except one end surface, the exterior is sealed preventing radon atoms from leaking out into the air. Areal exhalation rates are measured for six two-block objects linked together with pipes of different length. From these results, values of three parameters are deduced as (3.9 ± 0.5) x 10-8m2s-1, (6.9 ± 0.2) x 10-2, and (1.21 ± 0.09) x 105 atoms m-3s-1 for diffusion coefficient, porosity, and radon production rate, respectively. This value for diffusion coefficient agrees with that obtained by the one-block method within the experimental errors. The two-block method is shown to be useful to obtain the values of three parameters. Radium contents are obtained by the gamma-ray spectrometry for the concrete, and the materials used for it. The radon diffusion coefficient is measured also for the andesite used as a material of the concrete as (5.9 ± 0.3) x 10-10m2s-1. (author)

  16. Theoretical study on law of radon seepage exhalation from blasted uranium ore heap in shrinkage stope

    One dimensional differential equation for radon migration in the blasted uranium ore heap was established using radon seepage-diffusion migration theory, the formula for calculating the surface radon exhalation rate at the seepage exit in the blasted uranium ore heap was derived, and the methods for determining the relevant physical parameters were proposed. For a specific shrinkage stope, the influences of the air volume for ventilation, ore heap height and ore heap permeability on the radon exhalation rate were studied. The radon exhalation rate of the ore heap increases with the air volume for ventilation and gradually approaches its maximal value, but the growth rate decreases gradually with the increase of the air volume for ventilation. When the air volume for ventilation is small but is kept the same, the higher the ore heap is, the smaller the radon exhalation rate is. With the increase of the air volume for ventilation, the radon exhalation rate of the higher ore heap exceeds successively that of the lower ore heap, and the difference becomes larger and larger, and the higher the ore heap is, the larger the air volume for ventilation is for the radon exhalation rate to amount to its maximal value. The smaller the permeability of the ore heap is, the lower the radon exhalation rate of the heap is, the smaller the growth rate of the radon exhalation rate relative to the air volume is, and the larger the air volume for ventilation is for the radon exhalation rate to come to its maximal value. (authors)

  17. Radon exhalation in building materials of Bangalore Metropolitan, India

    Radiations ply an important role in the environment, as the world is naturally radioactive and human beings are exposed to naturally occurring background radiation. It is a fact that, radioactivity can be in the air we breathe, the soil on which we walk, the dwellings which we live and even within our bodies. This paper discusses the results of radon exhalation in building materials of Bangalore Metropolitan, India. The area of present study is Bangalore Metropolis covering an area of about 220 km2, situated at a latitude 1258 N and longitude of 7736 E with an average altitude of about 910 m above mean sea level. Solid State Nuclear Track Based CAN technique method is adopted for radon exhalation studies. The results of radon exhalation rate had a large fluctuation depending on the measurement points, samples and the building materials and the range of radon surface exhalation rates in the sites were varied from 96.0 to 725.6 mBqm-3h-1 with the arithmetic mean (AM) and geometric mean (GM) as 603.3 ± 18.6 and 578.9 ± 18.6 mBqm-3h-1 respectively. The correlation between the surface exhalation rates, mass exhalation and radon concentration in dwellings were 0.96 and 0.91 respectively. The back ground gamma radiation levels ranged from 3.7 to 5.6 mSvy-1with AM and GM as 4.7 ± 0.6 mSvy-1 respectively. The measurements showed the concentration levels are at alarming levels and demands proper control measures. The details are discussed. (author)

  18. Submarines, Spacecraft, and Exhaled Breath

    The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled b...

  19. Comparison of Select Analytes in Exhaled Aerosol from E-Cigarettes with Exhaled Smoke from a Conventional Cigarette and Exhaled Breaths

    Gerald A. Long

    2014-10-01

    Full Text Available Exhaled aerosols were collected following the use of two leading U.S. commercial electronic cigarettes (e-cigarettes and a conventional cigarette by human subjects and analyzed for phenolics, carbonyls, water, glycerin and nicotine using a vacuum-assisted filter pad capture system. Exhaled breath blanks were determined for each subject prior to each product use and aerosol collection session. Distribution and mass balance of exhaled e-cigarette aerosol composition was greater than 99.9% water and glycerin, and a small amount (<0.06% of nicotine. Total phenolic content in exhaled e-cigarette aerosol was not distinguishable from exhaled breath blanks, while total phenolics in exhaled cigarette smoke were significantly greater than in exhaled e-cigarette aerosol and exhaled breaths, averaging 66 µg/session (range 36 to 117 µg/session. The total carbonyls in exhaled e-cigarette aerosols were also not distinguishable from exhaled breaths or room air blanks. Total carbonyls in exhaled cigarette smoke was significantly greater than in exhaled e-cigarette aerosols, exhaled breath and room air blanks, averaging 242 µg/session (range 136 to 352 µg/session. These results indicate that exhaled e-cigarette aerosol does not increase bystander exposure for phenolics and carbonyls above the levels observed in exhaled breaths of air.

  20. "EXHALE"

    Quist, Morten; Langer, Seppo W; Rørth, Mikael; Christensen, Karl Bang; Adamsen, Lis

    2013-01-01

    in a group of advanced lung cancer patients (cardiovascular and strength training, relaxation). METHODS/DESIGN: A randomized controlled trial will test the effects of the exercise intervention in 216 patients with advanced lung cancer (non-small cell lung cancer (NSCLC) stage IIIb-IV and small cell...... present randomized controlled study will provide data on the effectiveness of a supervised exercise intervention in patients receiving systemic therapy for advanced lung cancer. It is hoped that the intervention can improve physical capacity and functional level, during rehabilitation of cancer patients...

  1. 42 CFR 84.91 - Breathing resistance test; exhalation.

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing resistance test; exhalation. 84.91...-Contained Breathing Apparatus § 84.91 Breathing resistance test; exhalation. (a) Resistance to exhalation...-circuit apparatus with a breathing machine as described in § 84.88, and the exhalation resistance...

  2. Nasal contribution to exhaled nitric oxide during exhalation against resistance or during breath holding

    Kharitonov, S. A.; Barnes, P. J.

    1997-01-01

    BACKGROUND: The concentration of nitric oxide (NO) is increased in the exhaled air of patients with inflammation of the airways, suggesting that this may be a useful measurement to monitor inflammation in diseases such as asthma. However, there have been concerns that exhaled NO may be contaminated by the high concentrations of NO derived from the upper airways, and that this may account for differences in reported values of exhaled NO using different techniques. A study was performed, ...

  3. Radon exhalation from granites used in Saudi Arabia.

    al-Jarallah, M

    2001-01-01

    Measurements of radon exhalation for a total of 50 selected samples of construction materials used in Saudi Arabia were taken using a radon gas analyzer. These materials included sand, aggregate, cement, gypsum, hydrated lime, ceramics and granite. It was found that the granite samples were the main source of radon emanations. A total of 32 local and imported granite samples were tested. It was found that the radon exhalation rates per unit area from these granite samples varied from not detectable to 10.6 Bq m-2 h-1 with an average of 1.3 Bq m-2 h-1. The linear correlation coefficient between emanated radon and radium content was 0.92. The normalized radon exhalation rates from 2.0 cm thick granite samples varied from not detectable to 0.068 (Bq m-2 h-1)/(Bq kg-1) with an average of 0.030 (Bq m-2 h-1)/(Bq kg-1). The average radon emanation of the granite samples was found to be 21% of the total radium concentration. Therefore, granite can be a source of indoor radon as well as external gamma-radiation from the uranium decay series. PMID:11378931

  4. Uranium distribution and radon exhalation from Brazilian dimension stones

    Amaral, P.G.Q.; Galembeck, T.M.B. [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil); Bonotto, D.M., E-mail: danielbonotto@yahoo.com.br [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil); Artur, A.C. [Departamento de Petrologia e Metalogenia, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, Sao Paulo (Brazil)

    2012-04-15

    This paper provides evaluations of the radiometric behavior and exhalation patterns of radon gas in decorative and dimension stones explored in the Brazilian states of Minas Gerais and Espirito Santo, given the importance of determining radon gas concentrations in human-inhabited environments. A total of 10 silicate rock types were studied, featuring different petrographic/petrophysical characteristics given by seven magmatic rocks (three of which are granitic pegmatites) and three metamorphic rocks. The study, comprising radiometric data of U and monitoring of {sup 222}Rn gas exhalation, shows a strong correlation between petrographic parameters and the physical properties of rocks. U levels ranged between 2.9 and 37 ppm, revealing a good coherence between the presence and the absence of radioactive element-bearing accessory minerals for each rock type. The rate of radon exhalation from the stones is related to the petrographic/petrophysical features of each material. By comparing the {sup 222}Rn level generated by a rock to the amount effectively emanated by it, the rate of emanated gas proves to be insignificant; also, a rock that produces more Rn will not always emanate more. Simulations performed to estimate the radon levels inside residences or any given indoor environment showed that nine samples attained values below the 4 pCi/L EPA limit, whereas one was above that limit. - Highlights: Black-Right-Pointing-Pointer Integration of distinct radiometric data acquired in dimension stones. Black-Right-Pointing-Pointer Dimension stones are extensively commercialized abroad. Black-Right-Pointing-Pointer Rn exhalation above the EPA threshold limit of 4 pCi/L.

  5. Radon Exhalation Considered in Building Material Standard

    2008-01-01

    <正>In order to investigate the relationship between radon exhalation and specific activity of natural nuclides in building material, here different kinds of samples of building materials were measured by the

  6. Exhaled CO, a predictor of lung function?

    Fabricius, P; Scharling, H; Lokke, A;

    2007-01-01

    BACKGROUND: Smoking is associated with an accelerated loss of lung function and inhalation accelerates the decline further. Exhaled CO reflects the exposure of smoke to the lungs. AIM: To investigate whether self-reported inhalation and type of cigarette influenced the level of exhaled CO and...... whether CO could provide additional information to usual measures of smoking regarding prediction of present lung function and decline in lung function over an extended period of time. METHOD: Cigarette smokers from the Copenhagen City Heart Study with valid measures of lung function and exhaled CO; in.......001). Increasing CO levels were correlated to a lower FEV(1)%pred and to an accelerated decline in lung function. However, in multiple linear regression analyses these correlations were not significant. CONCLUSION: Inhalation and type of cigarette affects exhaled CO levels. CO measures have no predictive value...

  7. Submarines, spacecraft and exhaled breath.

    Pleil, Joachim D; Hansel, Armin

    2012-03-01

    Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the submarine air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in submarines and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a submarine or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another

  8. Oropharyngeal origin of markers in exhaled breath

    Marteus, Helena

    2005-01-01

    Normal NO formation in the human airways occurs primarily in the nasal airways, where it is catalyzed by inducible NO synthase (iNOS), and in the oropharyngeal tract, via as yet not fully defined pathways. This NO can be detected in exhaled breath and when inflammation is present in the airways, for example in asthma, the concentration of NO is increased. Although most studies on non-invasive measurements of airway inflammation have focused on NO in exhaled breath, there has...

  9. Resonance particularity of natural radon exhalation

    Natural radon flows exhalated by rocks as a result of vibrational effects at a frequency in the range of 0-45 Hz were measured under laboratory conditions. Variations of volumetric activity of subsurface radon under natural conditions at a frequency of 16.6 Hz were determined. It was ascertained that the intensity of radon flow exhaled by rocks depends on the frequency of vibration effects. The maximum yield of radon is observed at frequencies about 16 and 32 Hz

  10. Comparison of active and passive methods for radon exhalation from a high-exposure building material

    The radon exhalation rates and radon concentrations in granite stones used in Iran were measured by means of a high-resolution high purity Germanium gamma-spectroscopy system (passive method) and an AlphaGUARD model PQ 2000 (active method). For standard rooms (4.0 x 35.0 m area x 32.8 height) where ground and walls have been covered by granite stones, the radon concentration and the radon exhalation rate by two methods were calculated. The activity concentrations of 226Ra in the selected granite samples ranged from 3.8 to 94.2 Bq kg-1. The radon exhalation rate from the calculation of the 226Ra activity concentration was obtained. The radon exhalation rates were 1.31-7.86 Bq m-2h-1. The direction measurements using an AlphaGUARD were from 218 to 1306 Bq m-3 with a mean of 625 Bq m-3. Also, the exhalation rates measured by the passive and active methods were compared and the results of this study were the same, with the active method being 22% higher than the passive method. (authors)

  11. Fractional exhaled nitric oxide measurement with a handheld device.

    Magori, Erhard; Hiltawsky, Karsten; Fleischer, Maximilian; Simon, Elfriede; Pohle, Roland; von Sicard, Oliver; Tawil, Angelika

    2011-06-01

    A sensing system for fractional exhaled nitric oxide (FeNO) measurement is presented, which is characterized by a compact setup and a cost potential to be made available for the patient at home. The sensing is based on the work function measurement of a phthalocyanine-type sensing material, which is shown to be sufficiently sensitive for NO(2) in the ppb range. The transducer used to measure the work function is a field effect transistor with a suspended gate electrode. Selectivity is given with respect to other breath components including typically metabolic by-products. The measurement system includes breath treatments in a simple setup, which essentially are dehumidification and a quantitative conversion of NO to NO(2) with a conversion rate of approx. 95%, using a disposable oxidation catalyst. The accomplishment of the correct exhalation maneuver and feeding of the suited portion of exhaled air to the sensor is provided by breath sampling means. The sensor is not gas consuming. This allows us to fill the measurement chamber once, instead of establishing a gas flow for the measurement. This feature simplifies the device architecture. In this paper, we report on sensor characteristics, system architecture and measurement with artificial breath-gas as well as with human breath with the device. PMID:21646688

  12. Radium concentration and radon exhalation measurements in the water around thermal power plants of north India

    Samples of water from different thermal power plants in northern India have been collected and analyzed for radium and radon concentration. For the measurements, α-sensitive LR-115 type II plastic track detectors are used. The radium and radon levels measured in some samples are high and thus unsafe from health point of view. Based upon the available data, the radon exhalation rates have been calculated. The radium concentration varies from 1.11 to 3.11 Bql-1 and the radon concentration varies from 10.64 to 29.78 pCil-1. The radon mass exhalation rates vary from 8.95 to 25.08 mBqkg-1hr-1 and surface exhalation rates vary from 245.21 to 690.24 mBqm-12hr-1 in different water samples. (author)

  13. Monitoring of thorium incorporation by thoron in breath measurement: Methodology improvements and determination of burdens of workers

    Thorium body burdens were determined from thoron (220Rn) in breath measurements: decay products of expired 220Rn were collected electrostatically and their progeny were subsequently measured by alpha-spectrometry. The volume of the 38.5 litre collection chamber was optimised with respect to the breathing rate, the decay constant of thoron, the electric field geometry and strength, and the humidity of air. Calibration was achieved by means of a calibrated 228Th source. A minimum detectable activity of 45 mBq 224Ra freely emanating 220Rn at the mouth (Ra equivalent) was achieved. Five Thorotrast patients were measured and data ranged from 40 up to 150 Bq Ra equivalent, indicating an exhalation factor of about 4.0 ± 1.9% of the total 220Rn produced in the body. Data from 53 workers showed burdens up to 23 Bq (mean 5.5 Bq) of thorium. Urine bioassays of samples from the same workers yielded corresponding results. In vivo measurements revealed no result above the detection limit of 25 Bq 208Tl. (author)

  14. Influencing effect of heat-treatment on radon emanation and exhalation characteristic of red mud

    The reuse of industrial by-products is important for members of numerous industrial sectors. However, though the benefits of reuse are evident from an economical point of view, some compounds in these materials can have a negative effect on users' health. In this study, the radon emanation and exhalation features of red mud were surveyed using heat-treatment (100–1200 °C). As a result of the 1200°C-treated samples, massic radon exhalation capacity reduced from 75 ± 10 mBq kg−1 h−1 to 7 ± 4 mBq kg−1 h−1, approximately 10% of the initial exhalation rate. To find an explanation for internal structural changes, the porosity features of the heat-treated samples were also investigated. It was found that the cumulative pore volume reduced significantly in less than 100 nm, which can explain the reduced massic exhalation capacity in the high temperature treated range mentioned above. SEM snapshots were taken of the surfaces of the samples as visual evidence for superficial morphological changes. It was found that the surface of the high temperature treated samples had changed, proving the decrement of open pores on the surface. - Highlights: • The radon exhalation depends on the heat-treatment temperature. The 1200 °C treated samples has only 10% radon exhalation of the initial. • A strong correlation was found between the porosity and the radon emanation and exhalation features. • Despite these promising results certain components can have an effect on one another, which in turn can cause harmful final structure

  15. Radon exhalation from sub-slab aggregate used in home construction in Canada

    Exposure to elevated levels of radon in homes has been shown to result in an increased risk of developing lung cancer. The two largest contributors to indoor radon are radon in soil gas, formed from the rocks and soil surrounding the home, and building materials such as aggregate. This study measured the surface radon exhalation rates for 35 aggregate samples collected from producers across Canada. The radon exhalation rates ranged from 2.3 to 479.9 Bq m-2 d-1, with a mean of 80.7±112 Bq m-2 d-1. Using a simple, conservative analysis, the aggregate contribution to radon concentrations in an unfinished basement was determined. The maximum estimated radon concentration was 32.5±2.7 Bq m-3, or ∼16 % of the Canadian Radon Guideline. It can be concluded that under normal conditions radon exhalation from aggregate contributes very little to the total radon concentration in indoor air. (authors)

  16. Protection of occupants from exhaled infectious agents and floor material emissions in rooms with personalized and underfloor ventilation

    Cermak, Radim; Melikov, Arsen Krikor

    2007-01-01

    pollutants associated with exhaled air and floor material emissions was evaluated at various combinations of personalized and underfloor airflow rates. Compared to underfloor ventilation alone, personalized and underfloor ventilation provided excellent protection Of seated occupants from any pollution, while...... the concentration of exhaled air pollution increased in the room. The two types of personalized ventilation performed differently. Subsequent analyses of airborne infection transmission risk indicated that personalized ventilation could become a supplement to traditional methods of infection control....

  17. 42 CFR 84.123 - Exhalation valve leakage test.

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY....123 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be subjected to...

  18. Measurements of Radon Exhalation Flux and Atmospheric Radon in Uranium Mining and Processing Sites

    The Nuclear Regulatory Authority (ARN) performs an environmental monitoring of areas around the different nuclear facilities. This environmental monitoring involves a periodical sampling and analysis in the areas surrounding the operating and decommissioned facilities for the mining and milling of uranium ores. This monitoring implies the sampling and measurements of natural uranium and 226Ra levels in surface waters, sediments and ground waters in each surrounding area. Moreover, radon exhalation flux measurements from uranium mill tailings and radon concentration in air are performed. Radon exhalation rate measurement is performed by activated charcoal adsorption followed by gamma spectrometry. In the case of radon gas measurements in air, they are carried out by several methods, mainly by nuclear track detectors (Makrofol and CR-39). In this work, the results related with radon exhalation flux measurements and radon concentration in air are presented and discussed. In addition, a full description of the methods used is presented. (author)

  19. Correlation between radon exhalation and radium content in granite samples used as construction material in Saudi Arabia

    Measurements of radon exhalation for a total of 205 selected samples of construction materials used in Saudi Arabia were carried out using an active radon gas analyzer with an emanation container. It was found that granite samples were the main source of radon exhalation. The radon exhalation rates per unit area from these granite samples varied from below the minimum detection limit up to 13.1Bqm-2h-1 with an average of 1.5 +/-1.9(1σ)Bqm-2h-1. The radium contents of 27 granite samples were measured using an HPGe-based γ spectroscopy setup. The 226Ra content of the granites varied from below the minimum detection limit up to 297Bqkg-1, with an average of 83+/-73(1σ)Bqkg-1. The linear correlation coefficient between exhaled radon and radium content was found to be 0.90

  20. Measurements of exhaled nitric oxide in healthy subjects age 4 to 17 years

    Buchvald, Frederik; Baraldi, Eugenio; Carraro, Silvia;

    2005-01-01

    NO was measured in healthy subjects of 4 to 17 years according to American Thoracic Society guidelines (single breath online, exhalation flow 50 mL/s) with a chemiluminescence analyzer (NIOX Exhaled Nitric Oxide Monitoring System, Aerocrine, Sweden) in 3 European and 2 US centers. Each child performed 3...... NO in 405 children was 9.7 ppb, and the upper 95% confidence limit was 25.2 ppb. FE NO increased significantly with age, and higher FE NO was seen in children with self-reported rhinitis/conjunctivitis or hay fever. The success rate was age-dependent and improved from 40% in the children 4 years old...

  1. An Experimental Study of Human Exhalation during Breathing and Coughing in a Mixing Ventilated Room

    Liu, Li; Lia, Yuguo; Nielsen, Peter V.;

    2009-01-01

    flow rates and temperatures for breathing and coughing, respectively. Smoke visualizations are conducted to show the formation, movement and vanishing of the exhalation jets from nose and mouth separately. The transient velocity distribution generated by breathing and coughing in different places......This study investigates the characteristics of human exhalation during breathing and coughing. Experiments employing one breathing thermal manikin are conducted in a full-scale test room with a mixing ventilation system. Two artificial lungs are used to generate discontinuous airflows with specific...

  2. Continuous Exhaled Breath Analysis on the Icu

    Bos, Lieuwe D. J.; Sterk, Peter J.; Schultz, Marcus J.

    2011-09-01

    During admittance to the ICU, critically ill patients frequently develop secondary infections and/or multiple organ failure. Continuous monitoring of biological markers is very much needed. This study describes a new method to continuously monitor biomarkers in exhaled breath with an electronic nose.

  3. CONTINUOUS EXHALED BREATH ANALYSIS ON THE ICU

    During admittance to the ICU, critically ill patients frequently develop secondary infections and/or multiple organ failure. Continuous monitoring of biological markers is very much needed. This study describes a new method to continuously monitor biomarkers in exhaled breath with an electronic nose.

  4. Exhaled CO, a predictor of lung function?

    Fabricius, Peder; Scharling, Henrik; Løkke, Anders;

    2007-01-01

    whether CO could provide additional information to usual measures of smoking regarding prediction of present lung function and decline in lung function over an extended period of time. METHOD: Cigarette smokers from the Copenhagen City Heart Study with valid measures of lung function and exhaled CO; in...

  5. Exhaled nitric oxide levels in exacerbations of asthma, chronic obstructive pulmonary disease and pneumonia

    Nitric oxide is known to be present in the exhaled air of normal subjects and at higher concentrations in asthmatics. The aim of this study was to measure exhaled nitric oxide levels in patients admitted to hospital with acute exacerbations of asthma, or chronic obstructive pulmonary disease, or with pneumonia. Within 24 hours of admission exhaled nitric oxide levels were measured by a chemiluminescent analyzer in 11 patients with acute sever asthma, 19 patients with acute exacerbation of chronic obstructive pulmonary disease, and in 12 patients with pneumonia. In asthmatics measurements were made on 3 occasions, at day 1, 4, and 28 and were related to changes in peak expiratory flow rate. On admission median exhaled nitric oxide levels (range) were significantly higher in asthmatics 22 (9.3-74) parts per billion in comparison to patients with chronic obstructive pulmonary disease 10.3 (2.7-34) parts per billion; p<0.01, pneumonia 7 (4-17) parts per billion; p<0.001, and normal subjects 8.7 (5-13.3) parts per billion; p<0.001. Following treatment the asthmatics had a significant reduction in their exhaled nitric oxide levels from 22 (9.3-74) parts per billion on day 1 to 9.7 (5.7-18.3) parts per billion on day 28; p=0.005. Peak expiratory flow rate measurements increased from 200 (120-280) l/min on day 1 to 280 (150-475) l/min on day 4; p<0.05 and to 390 (150-530) l/min on day 28; p<0.01. A strong negative correlation existed between peak expiratory flow rate measurements and exhaled nitric oxide levels in asthmatics on day 28 (r=-0.70; p=0.017). Acute exacerbations of asthma are associated with increased levels of exhaled nitric oxide in contrast to exacerbations of chronic obstructive pulmonary disease and acute pneumonia. Exhaled nitric oxide may be a useful indirect marker of asthmatic airway inflammation. The differing time course of response of nitric oxide to peak flow measures suggests that these two measures are reflecting differing airway events. (author)

  6. Analysis of Exhaled Breath for Disease Detection

    Amann, Anton; Miekisch, Wolfram; Schubert, Jochen; Buszewski, Bogusław; Ligor, Tomasz; Jezierski, Tadeusz; Pleil, Joachim; Risby, Terence

    2014-06-01

    Breath analysis is a young field of research with great clinical potential. As a result of this interest, researchers have developed new analytical techniques that permit real-time analysis of exhaled breath with breath-to-breath resolution in addition to the conventional central laboratory methods using gas chromatography-mass spectrometry. Breath tests are based on endogenously produced volatiles, metabolites of ingested precursors, metabolites produced by bacteria in the gut or the airways, or volatiles appearing after environmental exposure. The composition of exhaled breath may contain valuable information for patients presenting with asthma, renal and liver diseases, lung cancer, chronic obstructive pulmonary disease, inflammatory lung disease, or metabolic disorders. In addition, oxidative stress status may be monitored via volatile products of lipid peroxidation. Measurement of enzyme activity provides phenotypic information important in personalized medicine, whereas breath measurements provide insight into perturbations of the human exposome and can be interpreted as preclinical signals of adverse outcome pathways.

  7. The clinical value of exhaled nitric oxide in asthma

    Pisi, Roberta

    2012-01-01

    Bronchial asthma is an inflammatory disease and measurement of biomarkers in exhaled breath has recently become an attractive approach to non-invasively monitor airway inflammation. In bronchial asthma, increased fractional exhaled nitric oxide (FeNO) concentration in exhaled breath has been shown to reflect the extent of eosinophilic inflammation. Moreover, the increase of FeNO levels are suppressed by inhaled corticosteroids (ICS). Therefore, monitoring of FeNO is a useful marker of inf...

  8. Measurements of fractional exhaled nitric oxide in pediatric asthma

    Youn-Soo Hahn

    2013-01-01

    Exhaled nitric oxide (NO) has been extensively investigated as a noninvasive marker of airway inflammation in asthma. The increased NO expression induced by inflammatory mediators in airways can be monitored easily in exhaled air from asthmatic children. Based on the relationship between the increased NO expression and eosinophilic airway inflammation, fractional exhaled nitric oxide (FeNO) measurements become an important adjunct for the evaluation of asthma. In addition, the availability of...

  9. Exhaled breath analysis discriminates phenotypes of acute lung injury (ALI)

    Bos, L.D.J.; Hemmes, S.N.T.; Nijsen, T.M.E.; P. J. Sterk; Schultz, M.J

    2012-01-01

    Introduction It has been postulated that the pathophysiology and clinical presentation of ALI based on pulmonary and non-pulmonary etiology represent different phenotypes1. Until now, little biological evidence on the molecular level has been presented to support this hypothesis. Exhaled air contains volatile organic compounds (VOCs), metabolites of systemic or respiratory origin. Exhaled air metabolites may differ between diseases2. Molecular profiling of exhaled air of intubated and mechani...

  10. Exhalation of {sup 131}I after radioiodine therapy: measurements in exhaled air

    Schomaecker, Klaus; Sudbrock, Ferdinand; Fischer, Thomas; Dietlein, Markus; Kobe, Carsten; Gaidouk, Mark; Schicha, Harald [University of Cologne, Clinic of Nuclear Medicine, Cologne (Germany)

    2011-12-15

    A considerable amount of radioiodine is exhaled after radioiodine therapy leading to unwanted radiation exposure through inhalation. This study focused on the concentration of radioactivity exhaled and its chemical nature. Air exhaled by 47 patients receiving {sup 131}I-iodine for different thyroid diseases (toxic goitre n=26, Graves' disease n=13, thyroid cancer n=8) was investigated with a portable constant air-flow sampler. Different chemical iodine species were collected separately (organic, elemental and aerosolic) up to 26 h after administration of the radioiodine capsule. The data approximated to a monoexponential time-activity curve when integrated over 100 h. The radioactivity in the filters was measured with a well counter at defined time points after administration. The radioactivity of {sup 131}I in the exhaled air 1 h after administration ranged from 1 to 100 kBq/m{sup 3}. Two parameters (half-life of radioiodine exhalation and time-integrated activity over 100 h) were substantially higher in patients with cancer after near-total thyroidectomy (11.8 {+-} 2.1 h and 535 {+-} 140 kBq / m{sup 3}, respectively) than in patients with hyperfunctioning thyroid tissue due to toxic adenoma (7.6 {+-} 2.5 h and 115 {+-} 27 kBq/m{sup 3}, respectively) or Graves' disease (6.4 {+-} 3.6 h and 113 {+-} 38 kBq/m{sup 3}, respectively). The percentage of radioiodine in the exhaled air in relation to radioiodine administered to the patient was between 80 ppm and 150 ppm. The fraction of organically bound radioiodine (mean value) for all time points after administration was 94-99.9%. This percentage did not depend on the type of thyroid disease. The amount of exhaled radioiodine is small but by no means negligible on the first day after administration. This is the first study to provide experimental evidence on a systematic basis that radioiodine becomes exhalable in vivo, i.e. in the patient. The mechanism of organification of orally administered radioiodine

  11. Quantum cascade laser-based sensors for the detection of exhaled carbon monoxide

    Pakmanesh, Nahid; Cristescu, Simona M.; Ghorbanzadeh, Atamalek; Harren, Frans J. M.; Mandon, Julien

    2016-01-01

    Carbon monoxide (CO) is an important biomarker as it originates in the human body from the heme (component of hemoglobin) degradation. Tunable laser absorption spectroscopy in the mid-infrared wavelength region is used for sensitive trace gas sensing of exhaled carbon monoxide (CO). Based on a quantum cascade laser emitting at 4.61 µm, two different spectroscopic methods are investigated: off-axis integrated cavity output spectroscopy (OA-ICOS) and wavelength modulation 2f/1f spectroscopy (WMS). The optical sensors integrate a slow feedback system to correct for wavelength drifts improving their stability over days. Both approaches demonstrate a high reproducibility and sensitivity during online measurements of exhaled human breath. Considering the detection limit to be the equal to the standard deviation of the background fluctuations, the noise-equivalent detection limit for both OA-ICOS and WMS is 7 ppbv (1-s averaging time), leading to a noise-equivalent absorption sensitivity of 3.1 × 10-7 cm-1 Hz-1/2, which is sufficient for measurements of exhaled CO (eCO). Collection and measurements of eCO samples were investigated, and different exhalation flow rates and breath-holding time were explored, to provide a reliable sampling method for future medical investigations.

  12. Radon-222 exhalation from Danish building materials: H + H Industri A/S results

    Andersen, Claus Erik

    1999-01-01

    rate measurements for 10 samples of Danish building materials are reported. Samples include ordinary concrete, lightweight aggregate concrete,autoclaved aerated concrete, bricks, and gypsum board. The maximum mass-specific exhalation rate is about 20 m Bq h"-"1 kg "-"1. Under consideration of the......This report describes a closed-chamber method for laboratory measurements of the rate at which radon-222 degasses (exhales) from small building material samples. The chamber is 55 L in volume and the main sample geometry is a slab of dimensions 5x30x30cm"3 . Numerical modelling is used to assess...... specific applications of the investigated building materials, the contribution to the indoor radon-222concentration in a single-family reference house is calculated. Numerical modelling is used to help extrapolate the laboratory measurements on small samples to full scale walls. Application of typical...

  13. Evaluation of Acute Exogenous Hypoxia Impact on the Fraction of Exhaled Nitric Oxide in Healthy Males

    Dimov Peter K.

    2016-04-01

    Full Text Available Introduction: Exogenous hypoxia increases ventilation and contracts the pulmonary vessels. Whether those factors change the values of nitric oxide in exhaled air has not yet been evaluated. Objective: To examine the effect of exogenous normobaric hypoxia on the values of the fraction of nitric oxide in exhaled breath (FeNO. Subjects аnd Methods: Twenty healthy non-smoker males at mean age of 25.4 (SD = 3.7 were tested. The basal FeNO values were compared with those at 7 min. and 15 min. after introducing into the hypoxic environment (hypoxic tent, imitating atmospheric air with oxygen concentration corresponding to 3200 m above sea level. Exhaled breath temperature was measured at baseline and at 10-12 min. of the hypoxic exposition. Heart rate and oxygen saturation were registered by pulse-oximetry. Results: All the subjects had FeNO values in the reference range. The mean baseline value was 14.0 ± 3.2 ppb, and in hypoxic conditions - 15.5 ± 3.8 ppb (7 min. and 15.3 ± 3.6 ppb (15 min., respectively, as the elevation is statistically significant (p = 0.011 and p = 0.008. The values of exhaled breath temperature were 33.79 ± 1.55°С and 33.87 ± 1.83°С (p = 0.70 at baseline and in hypoxic conditions, respectively. Baseline oxygen saturation in all subjects was higher than that, measured in hypoxia (96.93 ± 1.29% vs. 94.27 ± 2.53%; p < 0.001. Conclusions: Exogenous hypoxia leads to an increase of FeNO values, but does not affect the exhaled breath temperature.

  14. NO in exhaled air of asthmatic children is reduced by the leukotriene receptor antagonist montelukast

    Bisgaard, H; Loland, L; Oj, J A

    1999-01-01

    -six asthmatic children 6 to 15 yr of age completed a double-blind crossover trial of 2 wk of treatment with 5 mg montelukast once daily versus placebo. FENO was measured during single-breath exhalation at a constant flow rate of 0.1 to 0.13 L/s against a resistance of 10 kPa/L/s. Eleven children were receiving...

  15. Study of radon exhalation from phosphogypsum plates and blocks from different origins

    Phosphogypsum is a waste of the fertilizer industry that concentrates radionuclides. In this work, the 222Rn exhalation rate from phosphogypsum plates and blocks from different origins used at dwellings construction was studied. The 222Rn exhalation rate was determined through the accumulation chamber technique with solid state nuclear track detectors (SSNTD). The effective dose for an individual living in a residence built with phosphogypsum based materials was evaluated. It also was calculated the 222Rn exhalation rate through the UNSCEAR model, from the 226Ra concentration in the materials, in order to compare the experimental results. It was evaluated the contribution of building component (paint) to the reduction of 222Rn exhalation rate. The plates and blocks were manufactured with phosphogypsum from Bunge Fertilizantes, Ultrafertil and Fosfertil. Blocks manufactured with ordinary gypsum was also evaluated. The average results obtained were 0.19 ± 0.06 Bq m-2 h-1, 1.3 ± 0.3 Bq m-2 h-1 and 0.41 ± 0.07 Bq m-2 h-1 for plates manufactured with phosphogypsum from Bunge Fertilizer, Ultrafertil and Fosfertil, respectively. For the phosphogypsum blocks the values were 0.11 ± 0.01 Bq m-2 h-1, 1.2 ± 0.6 Bq m-2 h-1, 0.47 ± 0.15 Bq m-2 h-1, for Bunge, Ultrafertil and Fosfertil. The blocks manufactured with ordinary gypsum presented average value of 0.18 ± 0.08 Bq m-2 h'-1. All phosphogypsum plates and blocks evaluated in this study presented effective dose for radon inhalation lower than the recommended value of 1mSv y-1, the annual effective dose limit for public exposure by International Commission on Radiological Protection. (author)

  16. Radon exhalation measurements in soil and rock samples of Chamaraja Nagar area, Karnataka State, India

    Natural radioactivity is widespread and omnipresent in earth's environment. The knowledge of distribution of radionuclide and radiation levels in the environment is important for assessing the effects of radiation exposure to human beings. Terrestrial radiation is due to the radionuclides present in different amounts in rocks, soils, building materials, water and atmosphere. The majority of radiation exposure of the population comes from radon, an α-radioactive, inert gas. Radon produces the main natural radiation exposure for human beings and has been recognized as carcinogenic gas. Radium and its ultimate precursor uranium are the main sources of radon. In the present study, Radon exhalation rate and Radium concentration in soil and rock samples around Chamaraja Nagar area of Karnataka state, India, are measured by SSNTD method, using can technique and LR-115 type II detectors. The radium activity in rock sample varies from 2.9 to 39.5 Bq.kg-1. Mass and Surface exhalation rate of radon in rock samples varies from 8.1 to 119.7 mBq.kg-11h-1 and 454.7 to 1787.3 mBq.m-2h-1 respectively. Radium concentration in soil samples has been found to vary from 3.6 to 34.1 Bq.kg-1 with an average value of 16.5 Bq.kg-1. The surface exhalation rate of radon 142 to 1377.3 mBq.m-2h-1. The mass exhalation rate of radon in soil samples has been found to vary from 10 to 31.4 mBq.kg-1h-1, with an average value of 19.3 mBq.kg-1h-1 and standard deviation of 7.6. (author)

  17. Increased amount of nitric oxide in exhaled air of asthmatics.

    Alving, K; Weitzberg, E; Lundberg, J M

    1993-10-01

    The presence of nitric oxide (NO) in the exhaled air of humans has recently been described. We wanted to assess at what level exhaled NO originates in normal airways, and to determine whether airway inflammation induces changes in the levels of exhaled NO. Exhaled NO was continuously measured by chemiluminescence technique during normal tidal breathing through the nose or mouth, with a detection limit of 1 part per billion (ppb). Twelve control subjects were compared to eight patients with mild atopic asthma and rhinitis caused by occupational allergen. In control subjects, the major part of NO in exhaled air (up to 30 ppb) seemed to originate in the nasal airways, with only minor contribution from the lower airways and the oral cavity. However, in mild asthmatics, the level of exhaled NO during oral breathing, indicating the involvement of the lower airways, was increased 2-3 fold. Since increased production of NO in the lower airways may involve activated macrophages or neutrophils, we suggest that exhaled NO may be used to instantly monitor ongoing bronchial inflammation, at least when involving inducible NO synthase. PMID:7507065

  18. Influence of building materials process technology on radon exhalation

    The building materials were produced through changing raw material ingredient, baking temperature, pressure difference between surface and interior of building material, grain diameter etc. Experiment indicates that change of raw material ingredient ratio can obviously influence the radon exhalation from building material, followed by baking temperature; and pressure difference does not have significant influence on radon exhalation. For the factory to produce shale-brick, the radon exhalation is relatively low under the condition that coal gangue accounts for 40%-50%, the grain diameter is less than 2 mm, the baking temperature is about 960 degree C or 1 020 degree C and the pressure difference is 85 kPa. (authors)

  19. Radon exhalation and natural radionuclides level in sediment of Cauvery riverine environment

    Human beings have always been exposed to natural radiation, which derive essentially from radionuclides present in 238U series, 232Th series and singly occurring radionuclides like 40K that are present in the earth's crust. Natural radioactivity is wide spread in the earth's environment and it exists in trace levels in soil, sediment, rock, plant, water and air. Among the various geological formations, sediment plays a predominant role in aquatic radioecology and plays a role in accumulating and transporting contaminants within the geographic area. It is the basic indicator of radiological contamination in the environment. However, sediment depositions on the bottom of rivers frequently consist of sand and gravel particles, which make them particularly valuable for the building construction in Karnataka and nearby states of India. Therefore, the radionuclides concentrations and their distributions, and its associated dose rates in the river sediments should be monitored. With this objective, the radioactivity level and the radon exhalation rate were studied in Cauvery river sediments. In the present study, the systematic measurement of activity concentration of 40K, 226Ra and 232Th, and radon exhalation rate in sediment sample of Cauvery river was measured. Activity of natural radionuclides were measured by HpGe gamma ray spectrometer and radon exhalation rate was measured by 'can' technique using SSNTD (LR115, Type IT). The mean values of 40K, 226Ra and 231Th in the sediment samples were found to be 144.3 Bq kg-1, 32.0 Bq kg-1 and 58.8 Bq kg-1 respectively. The mean value of radium concentration, Surface exhalation and Mass exhalation rate are 165.2 mBq kg-1, 345.4 mBq m-1 h-1, 150.7 mBq kg-1 h-1. To assess the radiological hazard of the natural radioactivity in the samples, Annual effective dose rate, internal hazard index (Hin), external hazard index (Hex), activity utilization index (AUI), excess lifetime cancer risk (ELCR) and annual

  20. Exhaled breath condensate sampling is not a new method for detection of respiratory viruses

    Maes Piet

    2011-03-01

    Full Text Available Abstract Background Exhaled breath condensate (EBC sampling has been considered an inventive and novel method for the isolation of respiratory viruses. Methods In our study, 102 volunteers experiencing upper airway infection were recruited over the winter and early spring of 2008/2009 and the first half of the winter of 2009/2010. Ninety-nine EBCs were successfully obtained and screened for 14 commonly circulating respiratory viruses. To investigate the efficiency of virus isolation from EBC, a nasal swab was taken in parallel from a subset of volunteers. The combined use of the ECoVent device with the RTube™ allowed the registration of the exhaled volume and breathing frequency during collection. In this way, the number of exhaled viral particles per liter air or per minute can theoretically be estimated. Results Viral screening resulted in the detection of 4 different viruses in EBC and/or nasal swabs: Rhinovirus, Human Respiratory Syncytial Virus B, Influenza A and Influenza B. Rhinovirus was detected in 6 EBCs and 1 EBC was Influenza B positive. We report a viral detection rate of 7% for the EBCs, which is much lower than the detection rate of 46.8% observed using nasal swabs. Conclusion Although very promising, EBC collection using the RTube™ is not reliable for diagnosis of respiratory infections.

  1. Development of method for quantification of 222Rn exhalation ratio at radioactive waste dam and soil study as mitigator material

    The Brazilian uranium mining company (INB) processed 2.32 106 tons of uranium ore in its ore treatment unit (UTM - Caldas), located in the Pocos de Caldas plateau. During 16 years of operation, this unit discarded 2.39 106 tons of solid waste in a tailing dam, with an average activity concentration of 226Ra of 7311 ± 184 Bq kg-1. Most of the atoms of 222Rn generated from the radioactive waste of the tailing dam remain bounded to the mineral structure. However, a fraction of these atoms can be released from the mineral structure and then emanate. Reaching the porous space of the waste piles, the 222Rn moves towards the interface waste-atmosphere, exhaling into the atmosphere. The featuring properties of the 222Rn transport and the biological damage caused by its progeny transform this small chain of radionuclides into a scourge of nature. Because of that, the dry area of the tailing dam was the scope of this work. A methodology was developed for quantifying the exhalation rate of 222Rn. Moreover, the soil from its surroundings was experimentally evaluated as a cover material to reduce the exhalation of 222Rn. A collector of 222Rn was developed, being denominated 607. This collector was proved to be exact and precise after laboratory tests, when a standard for 222Rn exhalation was prepared with caldasite, an uranium ore with high concentration of 226Ra (26611 ± 581 Bq kg-1), crushed to the granulometric interval from 1.168 mm to 0.589 mm. The results of 222Rn exhalation rate using the collector 607 were not influenced by the adsorption of water steam, considering sampling periods lower than 5 days and mass of water steam lower than 7 g. Sampling for measuring 222Rn exhalation rates in the dry area of the tailing dam was carried out using the collector 607, following the experimental design established by the United States Environmental Protection Agency (US EPA). The average exhalation rate in the west part of the tailing dam was 1.30 ± 1.24 Bq m-2 s-1 in the

  2. Measurements of Fractional Exhaled Nitric Oxide in Pediatric Asthma

    Youn-Soo Hahn

    2013-10-01

    Full Text Available Exhaled nitric oxide (NO has been extensively investigated as a noninvasive marker of airway inflammation in asthma. The increased NO expression induced by inflammatory mediators in airways can be monitored easily in exhaled air from asthmatic children. Based on the relationship between the increased NO expression and eosinophilic airway inflammation, fractional exhaled nitric oxide (FeNO measurements become an important adjunct for the evaluation of asthma. In addition, the availability of portable devices makes it possible to measure FeNO more easily and frequently in the routine pediatric practice. Despite various confounding factors affecting its levels, FeNO can be applicable in diagnosing asthma, monitoring treatment response, evaluating asthma control, and predicting asthma exacerbations. Thus, although pulmonary function tests are the standard tools for objective measurements of asthmatic control, FeNO can broaden the way of asthma monitoring and supplement standard clinical asthma care guidelines.

  3. Metabolite content profiling of bottlenose dolphin exhaled breath.

    Aksenov, Alexander A; Yeates, Laura; Pasamontes, Alberto; Siebe, Craig; Zrodnikov, Yuriy; Simmons, Jason; McCartney, Mitchell M; Deplanque, Jean-Pierre; Wells, Randall S; Davis, Cristina E

    2014-11-01

    Changing ocean health and the potential impact on marine mammal health are gaining global attention. Direct health assessments of wild marine mammals, however, is inherently difficult. Breath analysis metabolomics is a very attractive assessment tool due to its noninvasive nature, but it is analytically challenging. It has never been attempted in cetaceans for comprehensive metabolite profiling. We have developed a method to reproducibly sample breath from small cetaceans, specifically Atlantic bottlenose dolphins (Tursiops truncatus). We describe the analysis workflow to profile exhaled breath metabolites and provide here a first library of volatile and nonvolatile compounds in cetacean exhaled breath. The described analytical methodology enabled us to document baseline compounds in exhaled breath of healthy animals and to study changes in metabolic content of dolphin breath with regard to a variety of factors. The method of breath analysis may provide a very valuable tool in future wildlife conservation efforts as well as deepen our understanding of marine mammals biology and physiology. PMID:25254551

  4. Ethane and n-pentane in exhaled breath are biomarkers of exposure not effect

    Gorham, Katrine A; Andersen, Mads Peter Sulbæk; Meinardi, Simone; Delfino, Ralph J; Staimer, Norbert; Tjoa, Thomas; Rowland, F Sherwood; Blake, Donald R

    2009-01-01

    The relationship of exhaled ethane and n-pentane to exhaled NO, carbonylated proteins, and indoor/outdoor atmospheric pollutants were examined in order to evaluate ethane and n-pentane as potential markers of airway inflammation and/or oxidative stress. Exhaled NO and carbonylated proteins were...... inflammation or oxidative stress....

  5. Transmission of exhaled air between occupants in rooms with personalized and underfloor ventilation

    Cermak, Radim; Melikov, Arsen Krikor

    2004-01-01

    The exposure of occupants to exhaled air was examined at two different mixing zone heights of underfloor ventilation combined with two types of personalized ventilation by means of full-scale experiments. It is assumed that the air exhaled by people is one way of transmitting respiratory diseases...... occupied zone and thus has a substantial impact on the transmission of exhaled air....

  6. Associations of Exhaled Carbon Monoxide and Fractional Exhaled Nitric Oxide with Metabolic Syndrome: A Cohort Study

    Guo, Yanjun; Ma, Jixuan; Lu, Wei; He, Jintong; Zhang, Runbo; Yuan, Jing; Chen, Weihong

    2016-01-01

    Exhaled carbon monoxide (eCO) and fractional exhaled nitric oxide (FeNO) could reflect underlying inflammatory and oxidative stresses, which play important roles in pathogenetic pathways of metabolic syndrome (MetS). However, epidemiologic evidence was limited. We conducted a study in Wuhan-Zhuhai (WHZH) cohort of 3649 community participants to investigate the association between eCO, FeNO and MetS in both cross-sectional and prospective ways. The results showed that higher eCO and FeNO were associated cross-sectionally with a higher prevalence of MetS. The multivariable-adjusted odds ratios for MetS at baseline were 1.22 (95% confidence interval [CI]: 1.11 to 1.35) associated with per log eCO and 1.14 (95% CI: 1.00 to 1.30) associated with per log FeNO. During a follow-up of 3 years, 358/2181 new developed MetS cases were identified. Compared with lowest quartile of eCO and FeNO, the multivariable-adjusted risk ratios (95% CI) for MetS were 1.48 (1.06 to 2.06) related to the highest quartile of eCO. These findings remained consistent across sex but not smoking status, eCO was only associated with MetS in non-smokers when stratified by smoking status. In conclusion, our study demonstrated that eCO and FeNO were independently and positively associated with the prevalence of MetS cross-sectionally, while only eCO was positively related with the incidence of MetS prospectively. PMID:27076211

  7. Radon exhalation of hardening concrete: monitoring cement hydration and prediction of radon concentration in construction site

    Kovler, Konstantin [National Building Research Institute, Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Technion City, Haifa 32000 (Israel)]. E-mail: cvrkost@technion.ac.il

    2006-07-01

    The unique properties of radon as a noble gas are used for monitoring cement hydration and microstructural transformations in cementitious system. It is found that the radon concentration curve for hydrating cement paste enclosed in the chamber increases from zero (more accurately - background) concentrations, similar to unhydrated cement. However, radon concentrations developed within 3 days in the test chamber containing cement paste were {approx}20 times higher than those of unhydrated cement. This fact proves the importance of microstructural transformations taking place in the process of cement hydration, in comparison with cement grain, which is a time-stable material. It is concluded that monitoring cement hydration by means of radon exhalation method makes it possible to distinguish between three main stages, which are readily seen in the time dependence of radon concentration: stage I (dormant period), stage II (setting and intensive microstructural transformations) and stage III (densification of the structure and drying). The information presented improves our understanding of the main physical mechanisms resulting in the characteristic behavior of radon exhalation in the course of cement hydration. The maximum value of radon exhalation rate observed, when cement sets, can reach 0.6 mBq kg{sup -1} s{sup -1} and sometimes exceeds 1.0 mBq kg{sup -1} s{sup -1}. These values exceed significantly to those known before for cementitious materials. At the same time, the minimum ventilation rate accepted in the design practice (0.5 h{sup -1}), guarantees that the concentrations in most of the cases will not exceed the action level and that they are not of any radiological concern for construction workers employed in concreting in closed spaces.

  8. Analysis of international intercomparisons results organized by Japan for integrating 222Rn-220Rn detectors

    Objective: To guarantee the quality of measurements with the radon-thoron discriminative detectors of our laboratory. Methods: LD-P radon-thoron discriminative detector participated in the international intercomparison for integrating radon/thoron detectors organized by National Institute of Radiological Science (NIRS, Japan). Detectors were sent to NIRS for exposure. Radon intercomparison was conducted with radon chamber providing three levels of exposure: low, medium and high levels. Thoron intercomparison was carried out at thoron chamber, which also provided three levels of exposure: low, medium and high levels. Detectors were posted back to our laboratory for etching and analysis after exposure. Then the measured values were submitted to NIRS. Finally the reference values were informed of us. Results: The relative percent difference (RPD) between the measured value and the reference value for radon was -13.8%, -14.4% and -17.1% at low, medium and high levels respectively, and that of thoron were -14.4%, 8.9% and -3.2% at three levels respectively. Conclusions: Both radon and thoron measurement of our detectors rank as 'Category Ⅰ' in the 4th international intercomparisons for integrating radon/thoron detectors with the NIRS radon/thoron chambers. (authors)

  9. Thoron (220Rn) decay products removal in poorly ventilated environments using unipolar ionizers: Dosimetric implications

    Ionizers are proven to be effective in reducing the activity concentration of radon/thoron decay products in workplace environments. However, limited studies have been conducted on understanding the mechanism of removal and the related size dependency. This study demonstrates the feasibility of reducing the activity concentrations in small chambers and in room environments up to a factor of about 7. Field experiments in an uncontrolled ventilation area such as a thorium oxalate storage shed have also shown promising results with a possible concentration reduction by a factor of 4. However, these reductions have been necessarily associated with an increase (3-5 times) in the unattached fraction of the decay products which is a significant contributor to the lung dose. Owing to this, aspersions have been cast on the capability of the ionizers in reducing the effective dose. An attempt has been made here to estimate the effective doses over a wide range of parameters such as the initial unattached fraction, activity reduction ratio and the change in the unattached fraction, which get altered due to the use of ionizers. The study proves that for realistically achievable activity reduction ratios of about 3-5 with the employment of ionizers, the inhalation dose in workplace environments can be reduced by a factor of at least 4, as indicated by model calculations.

  10. An extensive indoor 222Rn/220Rn monitoring in North-East India

    The behaviour of ubiquitous radon (Rn222), thoron (Rn220) and their progeny in the indoor atmosphere generally reflect a complex interplay between a number of processes, the most important of which are radioactive α-decay, ventilation, attachment to aerosols and deposition on the surfaces. The present work involved a long-term (1997-2000) passive monitoring of Rn222 and Rn220 in the indoor environment of the North-Eastern region of India. This region being a zone of high seismicity, the indoor radon and thoron measurement of the region will provide a better insight and a valuable database for any study related to radon and thoron anomalies

  11. 222Rn, 220Rn and Progeny Measured in a Limestone Cave and the Associated Radiation Dose

    Concentrations of radon, thoron and the attached and unattached fractions of the short lived alpha emitting decay progeny were measured at different locations in a limestone cave by means of CR-39 and LR-115 type II solid state nuclear track detectors in order to assess the dose due to inhalation. The committed equivalent doses per hour of exposure due to the attached and unattached fractions of 218Po and 214Po were evaluated in different tissues of the respiratory tract. The influence of the activity of the attached and unattached fractions of 218Po and 214Po and the mass of the tissue on the committed equivalent dose per hour of exposure was investigated. The annual committed effective doses due to the attached and unattached fractions of 218Po and 214Po were determined. A maximum value of 1.7 mSv was found for workers spending 1 h/d during the summer months inside the cave. (author)

  12. Determination of activity of the 222-Rn and 220-Rn in the air aerosols

    The accumulation filter method at aerosol sampling stations in Bratislava was used. For the measurement of the accumulated total activity of the daughter products of the nuclides (Rn-222, Rn-220 of the U-238 and Th-232) natural decay series on the filters a low level alpha-beta proportional detector was used

  13. Development of one way entry and multiple pinholes based 222Rn - 220Rn discriminating dosimeter

    Simultaneous measurement of radon and thoron concentration in an environment is of great importance in the context of estimating correct inhalation dose and for epidemiological investigation. Track detector based cup dosimeter systems are widely used in dwellings environment for radon and thoron measurement due its cost effectiveness, portability and easy to use nature. In India, LR-115 detector based twin cup dosimeters developed by Eappen and Mayya have been used in dwelling for the last few decades for measurement of radon and thoron concentration in several places such as High Background Radiation Areas, Kerala. This dosimeter system has two cups, one exclusively for radon detection and other for both radon and thoron detection with two different entries for each cup. The cup detecting only radon uses a membrane to cut-off thoron transmission and thoron is determined using subtraction technique. However a key issue in this dosimeter system is that of arriving sometimes at a negative thoron concentration in the process of calculation. One of the reasons for this unwanted result can be attributed to the assumption of the entry of same amount of radon and thoron gas per unit time, in both cups. This assumption may not hold true sometimes, due to reasons like atmospheric turbulence. Another drawback of this dosimeter is that there is a very limited scope for optimization of radon and thoron transmission through the membrane discriminator. In this paper, we present a new design of 'Pin holes based twin cup dosimeter' with single entry and based on technique for discriminating the radon-thoron gases using multiple pinholes

  14. Low background counting of 222Rn, 220Rn and 219Rn with electrostatic counters

    Mong, Brian; EXO-200 Collaboration; nEXO Collaboration

    2014-09-01

    The radon counting technique based on electrostatic precipitation of progenies in gas followed by alpha spectroscopy has been applied to support the material selection programs of low background, neutrino and dark matter experiments with emphasis on EXO. An array of 8 counters operated by Laurentian University at SNOLAB and the Waste Isolation Pilot Plant have reached the sensitivity of 10 atoms/day in the uranium, thorium and actinium chains. Hardware improvements are underway to further increase the capacity and sensitivity in support of nEXO. The radon counting technique based on electrostatic precipitation of progenies in gas followed by alpha spectroscopy has been applied to support the material selection programs of low background, neutrino and dark matter experiments with emphasis on EXO. An array of 8 counters operated by Laurentian University at SNOLAB and the Waste Isolation Pilot Plant have reached the sensitivity of 10 atoms/day in the uranium, thorium and actinium chains. Hardware improvements are underway to further increase the capacity and sensitivity in support of nEXO. Supported by NSERC Project Grants ``Search for Double Beta Decay with EXO.''

  15. Study of the attachment between the decay products of 220Rn and monodisperse aerosols

    Attachment can be described in terms of one of two theories, viz. the diffusion theory or the kinetic theory. The diffusion theory is based on the transport of radioactive atoms by means of the process of diffusion. An attachment proportional to the radius R of the aerosol particles for the size range used in these experiments, is predicted by this theory. The kinetic theory is based on intermolecular collisions as described by the kinetic theory of gasses. This theory predicts an attachment that is proportional to R2. Both these relationships have been established by other researchers. However, the author believes that they have not taken several important parameters into consideration in their experiments, several such parameters were also not properly controlled in their experiments. In the present investigation the attachment flux for the attachment of thorium B atoms (of an approximate concentration of 4x103 atoms/cm3) to monodisperes polystyrene aerosols (of a radius from 0,5 to 2,5 μm) in the concentration range 1-30 particles/cm3, was directly measured. Steps were taken to prevent the formation of radiolytic nuclei, and all the relevant parameters were measured during the experiments. The attachment between the radioactive atoms and the aerosols was found to be directly proportional to the particle concentration N, as well as to R2. The sticking probability of atoms to a particle was found to be of the order of 0,1. The results show that the attachment was found; this was attributed to the attachment of radioactive atoms to agglomerate vapour molecules

  16. Protection of occupants from exhaled infectious agents and floor material emissions in rooms with personalized and underfloor ventilation

    Cermak, Radim; Melikov, Arsen Krikor

    2007-01-01

    The performance of two personalized. ventilation systems supplying air at the breathing zone was tested in conjunction with underfloor ventilation generating two different airflow patterns in a full-scale test room. Two breathing thermal manikins were used to simulate occupants. The distribution...... of pollutants associated with exhaled air and floor material emissions was evaluated at various combinations of personalized and underfloor airflow rates. Compared to underfloor ventilation alone, personalized and underfloor ventilation provided excellent protection Of seated occupants from any pollution, while...

  17. The correlations between Radon in soil gas and its exhalation and concentration in air in the southern part of Syria

    The aim of this work is to measure the concentration of the radon (222Rn) in soil air, 222Rn exhalation from soil and 222Rn in outdoor air which may have great influence on 222Rn levels in houses. 222Ra activity concentrations were also determined in soil samples. The studied areas are located in southern part of Syria. The common bed rock of this area is black and massive granite which are poor in uranium content [Jubeli Y.M., 1990. Uranium exploration in Syria. Internal Technical Report, vol. 1 (in English), vol. 2 (in Arabic), SAEC, Damascus; Technoexport (USSR), 1966. In: Ponikarov (Ed.), The Geological Map of Syria Scale: 1:200.000, Ministry of Industry, Damascus, Syria]. Results showed that the maximum measurement in all areas was 32500Bqm-3 in soil air with an exhalation rate of 9Bqm-2s-1 in Darra region and 66.43Bqm-3 of radon in open air, with 77Bqkg-1 of radium content in soil (Damascus suburb). In addition, correlations between Rn in soil and exhalation of Radon from soil and radon in houses were found in some areas (Sweda and Darra), while, no correlations were found in other studied areas. Moreover, no correlation between radon in houses and radon measurements in soil and in outdoors were found. This was attributed to the methodology used and the influence of building design and inhabitants behavior

  18. Exhaled carbon monoxide in asthmatics: a meta-analysis

    Huang Mao; Sun Yun; Bai Jianling; Yu Rongbin; Yao Xin; Zhang Jingying; Adcock Ian M; Barnes Peter J

    2010-01-01

    Abstract Background The non-invasive assessment of airway inflammation is potentially advantageous in asthma management. Exhaled carbon monoxide (eCO) measurement is cheap and has been proposed to reflect airway inflammation and oxidative stress but current data are conflicting. The purpose of this meta-analysis is to determine whether eCO is elevated in asthmatics, is regulated by steroid treatment and reflects disease severity and control. Methods A systematic search for English language ar...

  19. Exhaled nitric oxide measurements: clinical application and interpretation

    Taylor, D R; Pijnenburg, M W; Smith, A. D.

    2006-01-01

    The use of exhaled nitric oxide measurements (FEno) in clinical practice is now coming of age. There are a number of theoretical and practical factors which have brought this about. Firstly, FEno is a good surrogate marker for eosinophilic airway inflammation. High FEno levels may be used to distinguish eosinophilic from non‐eosinophilic pathologies. This information complements conventional pulmonary function testing in the assessment of patients with non‐specific respiratory symptoms. Secon...

  20. Exhalation pattern of thoron following incorporation of 224Ra

    The emanation factor (ω) of thoron was determined by means of thoron exhalation analysis as well as whole-body counting of 208Tl in 4 patients who had been injected intravenously with 224RaCl2 for treatment of Morbus Bechterew. At 5 hours after injection, ω was found to be 2.5 +- 0.3% remaining fairly constant during the period of examination (one week). (author)

  1. Exhaled nitric oxide in diagnosis and management of respiratory diseases

    Abba Abdullah

    2009-01-01

    Full Text Available The analysis of biomarkers in exhaled breath constituents has recently become of great interest in the diagnosis, treatment and monitoring of many respiratory conditions. Of particular interest is the measurement of fractional exhaled nitric oxide (FENO in breath. Its measurement is noninvasive, easy and reproducible. The technique has recently been standardized by both American Thoracic Society and European Respiratory Society. The availability of cheap, portable and reliable equipment has made the assay possible in clinics by general physicians and, in the near future, at home by patients. The concentration of exhaled nitric oxide is markedly elevated in bronchial asthma and is positively related to the degree of esinophilic inflammation. Its measurement can be used in the diagnosis of bronchial asthma and titration of dose of steroids as well as to identify steroid responsive patients in chronic obstructive pulmonary disease. In primary ciliary dyskinesia, nasal NO is diagnostically low and of considerable value in diagnosis. Among lung transplant recipients, FENO can be of great value in the early detection of infection, bronchioloitis obliterans syndrome and rejection. This review discusses the biology, factors affecting measurement, and clinical application of FENO in the diagnosis and management of respiratory diseases.

  2. Dispersal of Exhaled Air and Personal Exposure in Displacement Ventilated Rooms

    Bjørn, Erik; Nielsen, Peter Vilhelm

    2002-01-01

    from both nose and mouth is able to penetrate the breathing zone of another person standing nearby. The stratification of exhaled air breaks down if there is physical movement in the room. As movement increases, the concentration distribution in the room will move towards a fully mixed situation. The....... Numerical simulations support the experiments. Air exhaled through the mouth can lock in a thermally stratified layer, if the vertical temperature gradient in breathing zone height is sufficiently large. With exhalation through the nose, exhaled air flows to the upper part of the room. The exhalation flow......The influence of the human exhalation on flow fields, contaminant distributions, and personal exposures in displacement ventilated rooms is studied together with the effects of physical movement. Experiments are conducted in full-scale test rooms with life-sized breathing thermal manikins...

  3. Effect of oral L-arginine administration on exhaled nitric oxide (no) concentration in healthy volunteers

    Ogata, Hiroshi; Yatabe, Midori; Misaka, Shingen; Shikama, Yayoi; Sato, Suguru; Munakata, Mitsuru; Kimura, Junko

    2013-01-01

    We previously reported a case of pulmonary hypertension, where the symptoms were improved by oral L-arginine (arginine) administration. Arginine may increase nitric oxide (NO) production in the pulmonary artery. Exhaled NO may reflect pulmonary artery NO production. It has been demonstrated that exhaled NO concentration is higher in patients with allergic diseases, but whether oral arginine administration alters exhaled NO is unknown. Therefore, in this study, we investigated whether oral arg...

  4. Development of a practical testing procedure for the determination of radon exhalation from construction products

    The research project has confirmed that the measurement of radon exhalation from building products is possible and practicable using emission measuring chambers. Compared to conventional methodologies the measuring is closer to reality since indoor climate conditions as temperature, relative humidity and to some extent air exchange can be considered. The following topics are covered: requirements for a standardized methodology for the determination of radon exhalation from construction products, description of the methodology, description and discussion of exhalation measuring results.

  5. Distribution of Exhaled Contaminants and Personal Exposure in a Room using Three Different Air Distribution Strategies

    Olmedo, Inés; Nielsen, Peter V.; Adana, M. Ruiz de;

    2012-01-01

    The level of exposure to human exhaled contaminants in a room depends not only on the air distribution system but also on people’s different positions, the distance between them, people’s activity level and height, direction of exhalation, and the surrounding temperature and temperature gradient....... Human exhalation is studied in detail for different distribution systems: displacement and mixing ventilation as well as a system without mechanical ventilation. Two thermal manikins breathing through the mouth are used to simulate the exposure to human exhaled contaminants. The position and distance...

  6. Trace Analysis in End-Exhaled Air Using Direct Solvent Extraction in Gas Sampling Tubes: Tetrachloroethene in Workers as an Example

    Chris-Elmo Ziener

    2014-01-01

    Full Text Available Simple and cost-effective analytical methods are required to overcome the barriers preventing the use of exhaled air in routine occupational biological monitoring. Against this background, a new method is proposed that simplifies the automation and calibration of the analytical measurements. End-exhaled air is sampled using valveless gas sampling tubes made of glass. Gaseous analytes are transferred to a liquid phase using a microscale solvent extraction performed directly inside the gas sampling tubes. The liquid extracts are analysed using a gas chromatograph equipped, as usual, with a liquid autosampler, and liquid standards are used for calibration. For demonstration purposes, the method’s concept was applied to the determination of tetrachloroethene in end-exhaled air, which is a biomarker for occupational tetrachloroethene exposure. The method’s performance was investigated in the concentration range 2 to 20 μg tetrachloroethene/L, which corresponds to today’s exposure levels. The calibration curve was linear, and the intra-assay repeatability and recovery rate were sufficient. Analysis of real samples from dry-cleaning workers occupationally exposed to tetrachloroethene and from nonexposed subjects demonstrated the method’s utility. In the case of tetrachloroethene, the method can be deployed quickly, requires no previous experiences in gas analysis, provides sufficient analytical reliability, and addresses typical end-exhaled air concentrations from exposed workers.

  7. The correlation between exhalation from rocks and indoor concentration of 222Rn in the Sydney area

    The results of a survey of indoor 222Rn concentrations of 350 dwellings in the Sydney area are combined with measurements of 222Rn exhalation rates of principal rock types in the survey area. A linear regression is predicted which yields a positive regression coefficient of b=2.4±0.3, a constant of a=3.4±0.5, and a correlation coefficient of R2=0.15. This correlation was found to be highly significant by using three different statistical tests. The ratio of the indoor 222Rn concentrations in dwellings built on the two dominant rock types, the Wianamatta Shale and the Hawkesbury Sandstone, was found to be about 1.6. Copyright (2001) Australasian Radiation Protection Society Inc

  8. Online exhaled gas measurements for radiotherapy patients by proton transfer reaction mass spectrometry.

    Zou, Xue; Zhou, Wenzhao; Shen, Chengyin; Wang, Hongmei; Lu, Yan; Wang, Hongzhi; Chu, Yannan

    2016-08-01

    The present study assessed whether exhaled breath analysis using proton transfer reaction mass spectrometry (PTR-MS) could screen for radiation exposure. As the intensity of proton transfer reaction reagent ion H3(16)O(+) can be calculated with the intensity of H3(18)O(+), the intensity of H3(18)O(+) was monitored to observe the stability of the PTR-MS instrument during the experiment. The PTR-MS was applied for detecting the volatile organic compounds (VOCs) in the exhaled breath from 42 radiotherapy patients and other 61 patients who had not received radiotherapy. All patients were enrolled in the local cancer hospital. In the experiment, the subjects breathe slowly to the PTR-MS through a direct inlet system without any sampling bag or tube. The breath mass spectrometric data was statistically analyzed using Mann-Whitney U test and stepwise discriminant analysis to find the characteristic ions of radiation exposure. Receiver operating characteristics (ROC) analysis was applied for a combination of the characteristic ions. The PTR-MS instrument was stable as the intensity of reaction ion H3(16)O(+) was maintained in 1.1%. Through statistically analysis, we found 6 kinds of characteristic ions of radiation exposure, specifically mass-to-charge ratio (m/z) 93, m/z 41, m/z 102, m/z 79, m/z 131, and m/z 143. The sensitivity (true positive rate) and specificity (true negative rate) were 78.6% and 82.0% respectively. The integrated area under the ROC curve (AUC) was 0.869. The results in our study demonstrated the potential of the online breath tester PTR-MS as a non-invasive screening for radiation exposure. PMID:27209162

  9. Combined sensing platform for advanced diagnostics in exhaled mouse breath

    Fortes, Paula R.; Wilk, Andreas; Seichter, Felicia; Cajlakovic, Merima; Koestler, Stefan; Ribitsch, Volker; Wachter, Ulrich; Vogt, Josef; Radermacher, Peter; Carter, Chance; Raimundo, Ivo M.; Mizaikoff, Boris

    2013-03-01

    Breath analysis is an attractive non-invasive strategy for early disease recognition or diagnosis, and for therapeutic progression monitoring, as quantitative compositional analysis of breath can be related to biomarker panels provided by a specific physiological condition invoked by e.g., pulmonary diseases, lung cancer, breast cancer, and others. As exhaled breath contains comprehensive information on e.g., the metabolic state, and since in particular volatile organic constituents (VOCs) in exhaled breath may be indicative of certain disease states, analytical techniques for advanced breath diagnostics should be capable of sufficient molecular discrimination and quantification of constituents at ppm-ppb - or even lower - concentration levels. While individual analytical techniques such as e.g., mid-infrared spectroscopy may provide access to a range of relevant molecules, some IR-inactive constituents require the combination of IR sensing schemes with orthogonal analytical tools for extended molecular coverage. Combining mid-infrared hollow waveguides (HWGs) with luminescence sensors (LS) appears particularly attractive, as these complementary analytical techniques allow to simultaneously analyze total CO2 (via luminescence), the 12CO2/13CO2 tracer-to-tracee (TTR) ratio (via IR), selected VOCs (via IR) and O2 (via luminescence) in exhaled breath, yet, establishing a single diagnostic platform as both sensors simultaneously interact with the same breath sample volume. In the present study, we take advantage of a particularly compact (shoebox-size) FTIR spectrometer combined with novel substrate-integrated hollow waveguide (iHWG) recently developed by our research team, and miniaturized fiberoptic luminescence sensors for establishing a multi-constituent breath analysis tool that is ideally compatible with mouse intensive care stations (MICU). Given the low tidal volume and flow of exhaled mouse breath, the TTR is usually determined after sample collection via gas

  10. Exhaled breath analysis: physical methods, instruments, and medical diagnostics

    This paper reviews the analysis of exhaled breath, a rapidly growing field in noninvasive medical diagnostics that lies at the intersection of physics, chemistry, and medicine. Current data are presented on gas markers in human breath and their relation to human diseases. Various physical methods for breath analysis are described. It is shown how measurement precision and data volume requirements have stimulated technological developments and identified the problems that have to be solved to put this method into clinical practice. (instruments and methods of investigation)

  11. CFD Modeling and Image Analysis of Exhaled Aerosols due to a Growing Bronchial Tumor: towards Non-Invasive Diagnosis and Treatment of Respiratory Obstructive Diseases

    Xi, Jinxiang; Kim, JongWon; Si, Xiuhua A.; Corley, Richard A.; Kabilan, Senthil; Wang, Shengyu

    2015-02-06

    Diagnosis and prognosis of tumorigenesis are generally performed with CT, PET, or biopsy. Such methods are accurate, but have the limitations of high cost and posing additional health risks to patients. In this study, we introduce an alternative computer aided diagnostic tool that can locate malignant sites caused by tumorigenesis in a non-invasive and low-cost way. Our hypothesis is that exhaled aerosol distribution is unique to lung structure and is sensitive to airway structure vari-ations. With appropriate approaches, it is possible to locate the disease site, determine the disease severity, and subsequently formulate a targeted drug delivery plan to treat the disease. This study numerically evaluated the feasibility of the proposed breath test in an image-based lung model with varying pathological stages of a bronchial squamous tumor. Large eddy simulations and a Lagran-gian tracking approach were used to model respiratory airflows and aerosol dynamics. Respira-tions of tracer aerosols of 1 µm at a flow rate of 20 L/min were simulated, with the distributions of exhaled aerosols recorded on a filter at the mouth exit. Aerosol patterns were quantified with multiple analytical techniques such as concentration disparity, spatial scanning and fractal analysis. We demonstrated that a growing bronchial tumor induced notable variations in both the airflow and exhaled aerosol distribution. These variations became more apparent with increasing tumor severity. The exhaled aerosols exhibited distinctive pattern parameters such as spatial probability, fractal dimension, and multifractal spectrum. Results of this study show that morphometric measures of the exhaled aerosol pattern can be used to detect and monitor the pathological states of respiratory diseases in the upper airway. The proposed breath test also has the potential to locate the site of the disease, which is critical in developing a personalized, site-specific drug de-livery protocol.

  12. CFD modeling and image analysis of exhaled aerosols due to a growing bronchial tumor: Towards non-invasive diagnosis and treatment of respiratory obstructive diseases

    Diagnosis and prognosis of tumorigenesis are generally performed with CT, PET, or biopsy. Such methods are accurate, but have the limitations of high cost and posing additional health risks to patients. In this study, we introduce an alternative computer aided diagnostic tool that can locate malignant sites caused by tumorigenesis in a non-invasive and low-cost way. Our hypothesis is that exhaled aerosol distribution is unique to lung structure and is sensitive to airway structure variations. With appropriate approaches, it is possible to locate the disease site, determine the disease severity, and subsequently formulate a targeted drug delivery plan to treat the disease. This study numerically evaluated the feasibility of the proposed breath test in an image-based lung model with varying pathological stages of a bronchial squamous tumor. Large eddy simulations and a Lagrangian tracking approach were used to model respiratory airflows and aerosol dynamics. Respirations of tracer aerosols of 1 μm at a flow rate of 20 L/min were simulated, with the distributions of exhaled aerosols recorded on a filter at the mouth exit. Aerosol patterns were quantified with multiple analytical techniques such as concentration disparity, spatial scanning and fractal analysis. We demonstrated that a growing bronchial tumor induced notable variations in both the airflow and exhaled aerosol distribution. These variations became more apparent with increasing tumor severity. The exhaled aerosols exhibited distinctive pattern parameters such as spatial probability, fractal dimension, and multifractal spectrum. Results of this study show that morphometric measures of the exhaled aerosol pattern can be used to detect and monitor the pathological states of respiratory diseases in the upper airway. The proposed breath test also has the potential to locate the site of the disease, which is critical in developing a personalized, site-specific drug delivery protocol

  13. Primarily nasal origin of exhaled nitric oxide and absence in Kartagener's syndrome.

    Lundberg, J O; Weitzberg, E; Nordvall, S L; Kuylenstierna, R; Lundberg, J M; Alving, K

    1994-08-01

    The exact origin of nitric oxide (NO) in exhaled air is not known. We wanted to further investigate at what site exhaled NO is produced and to determine whether children with Kartagener's syndrome exhibited altered levels of exhaled NO. NO was measured by chemiluminescence technique in air sampled directly from the nose and in normally exhaled air of four children (2.5-13 years old) with Kartagener's syndrome, 20 healthy children, four healthy adults, and four conscious tracheostomized adults. NO was almost absent (98% reduced) in air sampled directly from the nose in four children with Kartagener's syndrome (4 +/- 1 parts per billion (ppb)), compared to age-matched controls (221 +/- 14 (ppb)). Tracheostomized adult subjects had considerably higher NO values in nasally (22 +/- 3 ppb) and orally (14 +/- 2 ppb) exhaled air, compared to levels in air exhaled through the tracheostomy (2 +/- 0 ppb). Treatment with intranasal corticosteroids for 14 days, or with antibiotics for 1 week, did not affect exhaled NO. These results clearly show that, basically, all NO in exhaled air of healthy subjects originates from the upper respiratory tract, with only a minor contribution from the lower airways. Furthermore, the absence of nasal NO in children with Kartagener's syndrome could be of use as a simple noninvasive diagnostic test. PMID:7957837

  14. Reduction in exhaled nitric oxide immediately after methacholine challenge in asthmatic children

    Piacentini, G; Bodini, A; Peroni, D; Del Giudice, M M.; Costella, S; Boner, A

    2002-01-01

    Background: The measurement of exhaled nitric oxide (NO) has recently been proposed as a useful technique for the evaluation of airway inflammation in asthma. The purpose of this study was to determine the effect of methacholine bronchial provocation on the levels of exhaled NO in asthmatic children. Method: Exhaled NO was measurement immediately before and after methacholine provocation in 51 children with mild to moderate asthma. Results: A significant decrease occurred in the level of exhaled NO (p<0.0001) after methacholine bronchial provocation which was not correlated with the percentage fall in forced expiratory volume in 1 second (FEV1). Conclusions: The methacholine test should not be used immediately before measurement of exhaled NO in children with asthma. PMID:12200520

  15. Indoor radon and its profile: a case study in Bangalore city, India

    The natural radioactivity gives rise to internal and external indoor exposure. The external exposure is caused by gamma radiation originating from the members of the 238U, 232Th decay series and from 40K. The internal radiation exposure mainly affecting the respiratory tract is caused by the short-lived daughter products of radon, which are exhaled from the construction material into the room air. The area of present study is Bangalore City. The common rocks are pink, grey and porphyries gneisses with large feldspars and black dolerite. An attempt has been made to study the 222Rn and 220Rn levels in different volume rooms for the environment of Bangalore city, India. Solid State Nuclear Track Detector based dosimeters were used for the measurement of 222Rn and 220Rn. Rooms of the dwellings were carefully categorized on the basis of interior volume such as 30 - 200 m3 further they were classified into four groups as 30-40 m3, 64-75 m3, 80-100 m3 and 110- 200 m3. The measured arithmetic mean concentrations of 222Rn and 220Rn for a period of 5 years were 81.06 and 57.54, 54.09 and 31.00, 43.36 and 22.63, 30.68 and 15.74,16.67 and 11.08 respectively. The inhalation dose rate in higher volume rooms varied from 0.77 to 3.24 mSvy-1 with an AM as 1.35 ± 0.03 and in lower volume rooms they were ranged from 2.24 to 3.83 mSvy1 with an AM as 2.94 ± 0.14. Higher concentrations and dose rates were observed in smaller volume room and the lower concentration were observed in bigger volume rooms irrespective of the seasons. Results are discussed in detail. (author)

  16. Exhalation velocity of radon-222 of Dutch building materials and the influence of paint systems

    In order to achieve a better insight concerning the source terms of radon in the Dutch dwelling in the framework of the RENA-programme an investigation has been performed into the exhalation velocity of radon-222 from building materials. From this investigation it turned out that the ventilation factor does not have any influence upon the exhalation velocity, neither an influence of alteration of air pressure could be demonstrated. The influence of air humidity upon the exhalation velocity showed a twofold picture; for gypsum a linear increase of the exhalation velocity with vapour pressure was found, while for concrete a linear decrease with vapour pressure was observed. Further it has been investigated in how far paint systems diminish the exhalation velocity of the Rn-222 from gypsum and concrete. Acryl paints, mostly used in the Dutch dwelling, did not show a decrease of the exhalation velocity and structure paints did even cause an increase of the exhalation velocity. Other types of paint based on chlorous rubber, epoxy resins and poly-urethane, in contrast, showed a clear reduction. From these those based on poly-urethane showed the largest reduction (60-75%) at a double sided treatment of the wall. With the help of a mathematical modelling of the exhalation estimations have been made of the exhalation velocity of Rn-222 at single sided treatment of a wall and for the exhalation velocity of Rn-220. For the fore mentioned poly-urethane-paints this yelds, at an estimate, a reduction of respectively 90-95% and 100%. (author). 40 refs.; 15 figs.; 8 tabs

  17. Gas analysis of human exhalation by tunable diode laser spectroscopy

    Stepanov, Eugene V.; Moskalenko, Konstantin L.

    1993-02-01

    Results of the application of a tunable diode laser (TDL) to determining the trace gas components of human exhalation are presented. The analyzer is specially developed to measure both carbon oxides (CO and CO2) in expired air. A few results illuminating possible applications of TDLs in high-sensitivity medical diagnostics have been obtained. For nonsmokers, expired concentrations of CO are slightly higher than those in inhaled air. The specific surplus value seems to be independent of the ambient atmospheric CO content. The surplus CO content increases by more than an order of magnitude just after intensive exercises, e.g., jogging. For smokers, the pharmacokinetic of abundant CO removal from the organism could be investigated by this technique, which provides quick and reliable measurements of smoking status. Breath-holding synchronous measurements of CO and CO2 in exhalation demonstrate behavior that is different with breath-holding time. The method seems useful for the investigation of phenomena such as molecular pulmonary diffusion through the alveolar-capillary membrane and an organism's adaptation to oxygen shortage. Prospects for the development and application of diode laser spectroscopy to trace gas analysis in medicine are also discussed.

  18. Exhaled nitric oxide in stable chronic obstructive pulmonary disease

    The objective of the study was to test the hypothesis that fraction of exhaled nitric oxide (FENO) is elevated in nonsmoking subjects with stable chronic obstructive pulmonary disease (COPD) and compare it with the results in patients with asthma and a control population. Pulmonology Clinic at a University Hospital. Twenty five control subjects, 25 steroid naive asthmatics and 14 COPD patients were studied. All the patients were nonsmokers and stable at the time of the study. All subjects completed a questionnaire and underwent spirometry. Exhaled nitric oxide was measured online by chemiluminescence, using single-breath technique. All the study subjects were males. Subjects with stable COPD had significantly higher values of FENO than controls (56.54+ - 28.01 vs 22.00 + -6.69; P =0.0001) but lower than the subjects with asthma (56.54+ - 28.01 vs 84.78+ - 39.32 P 0.0285). The FENO values in COPD subjects were inversely related to the FEV 1 /FVC ratio. There was a significant overlap between the FENO values in COPD and the control subjects. There is a significant elevation in FENO in patients with stable COPD, but the elevation is less than in asthmatic subjects. Its value in clinical practice may be limited by the significant overlap with control subjects. (author)

  19. Exhaled nitric oxide in stable chronic obstructive pulmonary disease

    Beg Mohammed

    2009-01-01

    Full Text Available Study Objective : The objective of the study was to test the hypothesis that fraction of exhaled nitric oxide (FENO is elevated in nonsmoking subjects with stable chronic obstructive pulmonary disease (COPD and compare it with the results in patients with asthma and a control population. Design : Cross-sectional study. Materials and Methods : Pulmonology Clinic at a University Hospital. Twenty five control subjects, 25 steroid naοve asthmatics and 14 COPD patients were studied. All the patients were nonsmokers and stable at the time of the study. All subjects completed a questionnaire and underwent spirometry. Exhaled nitric oxide was measured online by chemiluminescence, using single-breath technique. Results : All the study subjects were males. Subjects with stable COPD had significantly higher values of FENO than controls (56.54±28.01 vs 22.00±6.69; P =0.0001 but lower than the subjects with asthma (56.54±28.01 vs 84.78±39.32 P = 0.0285.The FENO values in COPD subjects were inversely related to the FEV 1 /FVC ratio. There was a significant overlap between the FENO values in COPD and the control subjects. Conclusion : There is a significant elevation in FENO in patients with stable COPD, but the elevation is less than in asthmatic subjects. Its value in clinical practice may be limited by the significant overlap with control subjects.

  20. Chemiresistive Electronic Nose toward Detection of Biomarkers in Exhaled Breath.

    Moon, Hi Gyu; Jung, Youngmo; Han, Soo Deok; Shim, Young-Seok; Shin, Beomju; Lee, Taikjin; Kim, Jin-Sang; Lee, Seok; Jun, Seong Chan; Park, Hyung-Ho; Kim, Chulki; Kang, Chong-Yun

    2016-08-17

    Detection of gas-phase chemicals finds a wide variety of applications, including food and beverages, fragrances, environmental monitoring, chemical and biochemical processing, medical diagnostics, and transportation. One approach for these tasks is to use arrays of highly sensitive and selective sensors as an electronic nose. Here, we present a high performance chemiresistive electronic nose (CEN) based on an array of metal oxide thin films, metal-catalyzed thin films, and nanostructured thin films. The gas sensing properties of the CEN show enhanced sensitive detection of H2S, NH3, and NO in an 80% relative humidity (RH) atmosphere similar to the composition of exhaled breath. The detection limits of the sensor elements we fabricated are in the following ranges: 534 ppt to 2.87 ppb for H2S, 4.45 to 42.29 ppb for NH3, and 206 ppt to 2.06 ppb for NO. The enhanced sensitivity is attributed to the spillover effect by Au nanoparticles and the high porosity of villi-like nanostructures, providing a large surface-to-volume ratio. The remarkable selectivity based on the collection of sensor responses manifests itself in the principal component analysis (PCA). The excellent sensing performance indicates that the CEN can detect the biomarkers of H2S, NH3, and NO in exhaled breath and even distinguish them clearly in the PCA. Our results show high potential of the CEN as an inexpensive and noninvasive diagnostic tool for halitosis, kidney disorder, and asthma. PMID:27456161

  1. Development and Performance Evaluation of an Exhaled-Breath Bioaerosol Collector for Influenza Virus.

    McDevitt, James J; Koutrakis, Petros; Ferguson, Stephen T; Wolfson, Jack M; Fabian, M Patricia; Martins, Marco; Pantelic, Jovan; Milton, Donald K

    2013-01-01

    The importance of the aerosol mode for transmission of influenza is unknown. Understanding the role of aerosols is essential to developing public health interventions such as the use of surgical masks as a source control to prevent the release of infectious aerosols. Little information is available on the number and size of particles generated by infected persons, which is partly due to the limitations of conventional air samplers, which do not efficiently capture fine particles or maintain microorganism viability. We designed and built a new sampler, called the G-II, that collects exhaled breath particles that can be used in infectivity analyses. The G-II allows test subjects to perform various respiratory maneuvers (i.e. tidal breathing, coughing, and talking) and allows subjects to wear a mask or respirator during testing. A conventional slit impactor collects particles > 5.0 μm. Condensation of water vapor is used to grow remaining particles, including fine particles, to a size large enough to be efficiently collected by a 1.0 μm slit impactor and be deposited into a buffer-containing collector. We evaluated the G-II for fine particle collection efficiency with inert particle aerosols and evaluated infective virus collection using influenza A virus aerosols. Testing results showed greater than 85% collection efficiency for particles greater than 50nm and influenza virus collection comparable with a reference SKC BioSampler®. The new design will enable determination of exhaled infectious virus generation rate and evaluate control strategies such as wearing a surgical type mask to prevent the release of viruses from infected persons. PMID:23418400

  2. Study of radon exhalation from phosphogypsum plates and blocks from different origins; Estudo da exalacao de radonio em placas e tijolos de fosfogesso de diferentes procedencias

    Costa, Lucas Jose Pereira da

    2011-07-01

    Phosphogypsum is a waste of the fertilizer industry that concentrates radionuclides. In this work, the {sup 222}Rn exhalation rate from phosphogypsum plates and blocks from different origins used at dwellings construction was studied. The {sup 222}Rn exhalation rate was determined through the accumulation chamber technique with solid state nuclear track detectors (SSNTD). The effective dose for an individual living in a residence built with phosphogypsum based materials was evaluated. It also was calculated the {sup 222}Rn exhalation rate through the UNSCEAR model, from the {sup 226}Ra concentration in the materials, in order to compare the experimental results. It was evaluated the contribution of building component (paint) to the reduction of {sup 222}Rn exhalation rate. The plates and blocks were manufactured with phosphogypsum from Bunge Fertilizantes, Ultrafertil and Fosfertil. Blocks manufactured with ordinary gypsum was also evaluated. The average results obtained were 0.19 {+-} 0.06 Bq m-2 h-1, 1.3 {+-} 0.3 Bq m{sup -2} h{sup -1} and 0.41 {+-} 0.07 Bq m{sup -2} h{sup -1} for plates manufactured with phosphogypsum from Bunge Fertilizer, Ultrafertil and Fosfertil, respectively. For the phosphogypsum blocks the values were 0.11 {+-} 0.01 Bq m{sup -2} h-1, 1.2 {+-} 0.6 Bq m{sup -2} h{sup -1}, 0.47 {+-} 0.15 Bq m{sup -2} h{sup -1}, for Bunge, Ultrafertil and Fosfertil. The blocks manufactured with ordinary gypsum presented average value of 0.18 {+-} 0.08 Bq m{sup -2} h'-{sup 1}. All phosphogypsum plates and blocks evaluated in this study presented effective dose for radon inhalation lower than the recommended value of 1mSv y{sup -1}, the annual effective dose limit for public exposure by International Commission on Radiological Protection. (author)

  3. Leukotrienes in exhaled breath condensate and fractional exhaled nitric oxide in workers exposed to TiO2 nanoparticles.

    Pelclova, Daniela; Zdimal, Vladimir; Kacer, Petr; Fenclova, Zdenka; Vlckova, Stepanka; Komarc, Martin; Navratil, Tomas; Schwarz, Jaroslav; Zikova, Nadezda; Makes, Otakar; Syslova, Kamila; Belacek, Jaroslav; Zakharov, Sergey

    2016-01-01

    Human health data regarding exposure to nanoparticles are extremely scarce and biomonitoring of exposure is lacking in spite of rodent pathological experimental data. Potential markers of the health-effects of engineered nanoparticles were examined in 30 workers exposed to TiO2 aerosol, 22 office employees of the same plant, and 45 unexposed controls. Leukotrienes (LT) B4, C4, E4, and D4 were analysed in the exhaled breath condensate (EBC) and urine via liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Fractional exhaled nitric oxide (FeNO) and spirometry was also measured. The median particle number concentration of the aerosol in the production ranged from 1.98  ×  10(4) to 2.32  ×  10(4) particles cm(-3); about 80% of the particles were  spirometry significant impairment in the workers was seen only for %VCIN and %PEF (both p  Spirometry was not sensitive enough. PMID:27356965

  4. Hydrogen peroxide in exhaled breath condensate: A clinical study

    C Nagaraja

    2012-01-01

    Full Text Available Objectives: To study the ongoing inflammatory process of lung in healthy individuals with risk factors and comparing with that of a known diseased condition. To study the inflammatory response to treatment. Background: Morbidity and mortality of respiratory diseases are raising in trend due to increased smokers, urbanization and air pollution, the diagnosis of these conditions during early stage and management can improve patient′s lifestyle and morbidity. Materials and Methods: One hundred subjects were studied from July 2010 to September 2010; the level of hydrogen peroxide concentration in exhaled breath condensate was measured using Ecocheck. Results: Of the 100 subjects studied, 23 were healthy individuals with risk factors (smoking, exposure to air pollution, and urbanization; the values of hydrogen peroxide in smokers were 200-2220 nmol/l and in non-smokers 340-760 nmol/l. In people residing in rural areas values were 20-140 nmol/l in non-smokers and 180 nmol/l in smokers. In chronic obstructive pulmonary disease cases, during acute exacerbations values were 540-3040 nmol/l and 240-480 nmol/l following treatment. In acute exacerbations of bronchial asthma, values were 400-1140 nmol/l and 100-320 nmol/l following treatment. In cases of bronchiectasis, values were 300-340 nmol/l and 200-280 nmol/l following treatment. In diagnosed pneumonia cases values were 1060-11800 nmol/l and 540-700 nmol/l following treatment. In interstitial lung diseases, values ranged from 220-720 nmol/l and 210-510 nmol/l following treatment. Conclusion: Exhaled breath condensate provides a non-invasive means of sampling the lower respiratory tract. Collection of exhaled breath condensate might be useful to detect the oxidative destruction of the lung as well as early inflammation of the airways in a healthy individual with risk factors and comparing the inflammatory response to treatment.

  5. Impact of structural parameters on the radon exhalation of building materials: Preliminary study

    Samples of mortar and sand-lime pieces with different percentages of fly ash are hardened at different relative humidities. The porosity distribution, the moisture and the radon exhalation of these samples are determined. Based on the data of the above-mentioned analyses, the thickness of the adsorbed water layer in the water-filled pores is estimated. The correlation between the structural parameters and the radon exhalation is investigated. If the radon exhalation process can be modelled, the radiation risk of applying fly ash in building materials can be controlled or reduced. The results do not yet show a clear indication. The applied methods have to be considered in more detail

  6. CFD Analysis of the Human Exhalation Flow using Different Boundary Conditions and Ventilation Strategies

    Villafruela, J.M.; Olmedo, Inés; Ruiz de Adana, M.;

    2013-01-01

    different environmental conditions and to validate whether a steady boundary condition of the exhalation flow may simulate human breathing in an effective and accurate way. The results show a very good agreement of the numerical results obtained for Test a and the experimental data. This fact confirms the...... use of numerical simulation as a powerful tool to predict the contaminant distribution exhaled by a human. The numerical tests with steady boundary conditions for the exhalation flow require a transitory resolution procedure and the predictions provided by these models display some discrepancies with...

  7. The lung cancer breath signature: a comparative analysis of exhaled breath and air sampled from inside the lungs

    Capuano, Rosamaria; Santonico, Marco; Pennazza, Giorgio; Ghezzi, Silvia; Martinelli, Eugenio; Roscioni, Claudio; Lucantoni, Gabriele; Galluccio, Giovanni; Paolesse, Roberto; di Natale, Corrado; D'Amico, Arnaldo

    2015-11-01

    Results collected in more than 20 years of studies suggest a relationship between the volatile organic compounds exhaled in breath and lung cancer. However, the origin of these compounds is still not completely elucidated. In spite of the simplistic vision that cancerous tissues in lungs directly emit the volatile metabolites into the airways, some papers point out that metabolites are collected by the blood and then exchanged at the air-blood interface in the lung. To shed light on this subject we performed an experiment collecting both the breath and the air inside both the lungs with a modified bronchoscopic probe. The samples were measured with a gas chromatography-mass spectrometer (GC-MS) and an electronic nose. We found that the diagnostic capability of the electronic nose does not depend on the presence of cancer in the sampled lung, reaching in both cases an above 90% correct classification rate between cancer and non-cancer samples. On the other hand, multivariate analysis of GC-MS achieved a correct classification rate between the two lungs of only 76%. GC-MS analysis of breath and air sampled from the lungs demonstrates a substantial preservation of the VOCs pattern from inside the lung to the exhaled breath.

  8. Markers of oxidative stress in exhaled breath of workers exposed to iron oxide nanoparticles are elevated

    Pelclová, D.; Fenclová, Z.; Navrátil, Tomáš; Vlčková, Š.; Syslová, K.; Kuzma, Marek; Ždímal, Vladimír; Schwarz, Jaroslav; Pušman, Jan; Zíková, Naděžda; Zakharov, S.; Machajová, M.; Kačer, P.

    2014-01-01

    Roč. 7, Suppl. 1 (2014), s. 69-70. ISSN 1337-6853 Institutional support: RVO:61388971 ; RVO:61388955 ; RVO:67985858 Keywords : oxidative stress * exhaled breath * nanoparticles Subject RIV: CF - Physical ; Theoretical Chemistry

  9. Standardization of exhaled breath condensate (EBC) collection using a feedback regulated breathing pattern

    Collection of exhaled breath condensate (EBC) fluid by cooling of expired breath is a potentially valuable approach for the detection of biomarkers associated with disease or exposure to xenobiotics. EBC is generally collected using unregulated breathing patterns, perceived to el...

  10. High-sensitivity sensor of gases based on IR tunable diode lasers for human exhalation monitoring

    Moskalenko, Konstantin L.; Nadezhdinskii, Alexander I.; Stepanov, Eugene V.

    1991-06-01

    Results on tunable diode laser spectroscopy applications in analysis of human expiration are presented. Carbon monoxide concentrations in exhaled air of several non-smoking adults were measured with high sensitivity. Obtained CO contents slightly exceed atmosphere level and correlate with it. Simultaneous measurements of carbon monoxide and carbon dioxide were carried out using single diode laser generated at 4.7 microns. Dependences of their concentration in exhaled air on breath-holding time were investigated.