Low-level radon activity concentration—A metroRADON international intercomparison

An international comparison of continuous monitors measuring radon activity concentration was performed to validate the traceability of the European radon calibration facilities. It was carried out by comparing the secondary standards used by these previous facilities, ranging from 100 Bq·m-3 to 300 Bq·m-3. Secondary standards were individually compared to a secondary reference device previously calibrated in a reference radon atmosphere traceable to a primary standard. The intercomparison was organized by the National Institute for Nuclear, Chemical, and Biological Protection (SUJCHBO) in the period from October 2019 to April 2020 within the European Metrology Program for Innovation and Research (EMPIR), JRP-Contract 16ENV10 MetroRADON. Eight European laboratories participated in this study. The results of the experiment are presented and discussed.Peer ReviewedPostprint (published version

The Metrological Traceability, Performance and Precision of European Radon Calibration Facilities

An interlaboratory comparison for European radon calibration facilities was conducted to evaluate the establishment of a harmonized quality level for the activity concentration of radon in air and to demonstrate the performance of the facilities when calibrating measurement instruments for radon. Fifteen calibration facilities from 13 different European countries participated. They represented different levels in the metrological hierarchy: national metrology institutes and designated institutes, national authorities for radiation protection and participants from universities. The interlaboratory comparison was conducted by the German Federal Office for Radiation Protection (BfS) and took place from 2018 to 2020. Participants were requested to measure radon in atmospheres of their own facilities according to their own procedures and requirements for metrological traceability. A measurement device with suitable properties was used to determine the comparison values. The results of the comparison showed that the radon activity concentrations that were determined by European calibration facilities complying with metrological traceability requirements were consistent with each other and had common mean values. The deviations from these values were normally distributed. The range of variation of the common mean value was a measure of the degree of agreement between the participants. For exposures above 1000 Bq/m3, the variation was about 4% for a level of confidence of approximately 95% (k=2). For lower exposure levels, the variation increased to about 6%

Measurement of protection factor of respiratory protective devices toward nanoparticles

International audienceThe use of nanoparticles in industry has increased spectacularly over the past few years. Additionally, nanoscale particles seem to be the cause of new professional exposure situations. Due to their size, these particles may build up within the respiratory tract and may even reach the nervous system via the nasal passages; for this reason, it is generally recommended to wear respiratory protective devices (RPDs) in situations where collective protection is impossible to implement or inadequate. Here, we present the test bench ETNA designed to study the efficiency of RPDs in the presence of nanoparticles. The results of the efficiency measurement of two RPDs for two positions (sealed and unsealed) on a Sheffield head, for two inhalation configurations (constant flow and cyclic flow), and for two different particle size distributions of NaCl aerosol (one centered on 13nm and the other on 59nm) are presented below. The measurements indicate that when the leaks are negligible at the interface mask/head, the efficiency of RPD is greater for nanoparticles. For major leaks, the device's protection factor changes independently of the size of the particles. Furthermore, no trends with respect to the effect of the respiration type (constant-flow and cyclic-flow tests) have been shown on the device's protection factor

Incidence des fuites sur le facteur de protection d'un demi-masque filtrant

National audienceLes particules de taille nanométrique pourraient représenter un risque de plus en plus important pour la santé des travailleurs du fait du fort développement des nanotechnologies. Lorsqu'il n'est pas possible de réduire le risque à la source, l'Appareil de Protection Respiratoire filtrant (APR) est un des moyens utilisés pour réduire l'exposition à certaines substances nocives, dont les particules. L'objectif de notre étude est de déterminer dans quelle mesure ces appareils sont performants pour des particules de taille nanométrique. Nous présentons ici le banc dédié à la mesure de l'efficacité des APR en présence de nanoparticules, en se rapprochant au mieux des conditions réelles d'utilisation. Les mesures obtenues pour un APR montrent une efficacité pour les nanoparticules d'autant plus importante que les fuites à l'interface masque/tête sont faibles. Pour des fuites importantes, l'évolution du facteur de protection de l'appareil est indépendante de la taille des particules. On observe la même tendance en présence de fuites calibrées

Mass Transfer of Diffusive Species with Nonconstant In-Flight Formation and Removal in Laminar Tube Flow. Application to Unattached Short-Lived Radon Daughters

International audienceThis article deals with convective-diffusive aerosol transport within-flight formation and removal and is applied to the un attached fraction ofshort-lived radon decay products. Two novel contributions to previous studies aregiven in this numerical and experimental work: on the one hand, we solve themass-transport equations for all the short-lived radon daughters; on the otherhand, we include the 218Po neutralization into the mass-transport equation of thefirst radon decay product. Concerning the mass-transfer of all short-lived radondaughters, numerical calculations lead to the development of simple correlationsfor the 214Pb and 214Bi penetration fractions. Those correlations can be used todetermine the diffusion coefficient of 214Pb and 214Bi using the 2-filter method. Inour experiments, a diffusion coefficient equal to 5 x 10- 6 m2/s is found for the214Pb. Concerning the 218Po neutralization, better agreement is observed betweenour numerical and experimental results when 218Po neutralization is taken intoaccount. These results confirm the neutralization rates found by Howard andStrange (1994)

Deposition of nanosized particles in cylindrical tubes under laminar and turbulent flow conditions

International audienceThere are few studies of deposition of nanoparticles due to di$culties in their generation and size measurement. These di$culties can be overcome by the use of radioactive nanoparticles (Po). This aerosol is obtained with a constant production rate from radon decay, and its concentration is determined using nuclear measurement techniques. We present an experimental and numerical study of Po deposition in laminar and turbulent tube #ows, in order to validate the appropriated theories. For laminar #ows, we observe a better correlation between our experimental and numerical results, as these take into account, unlike analytical theories, all the phenomena occurring. For turbulent #ows, the theories which are the most suitable are those of Wells and Chamberlain (1967, Brit. J. Appl. Phys. 18, 1793}1799) and Friedlander (1977, Smoke, Dust and Haze, Wiley, New York). Our experimental results show that an unexpected surface e!ect on nanoparticles deposition can be observed, even for a hydraulically smooth surface. We also assessed the in#uence of surface roughness on nanoparticle deposition experimentally. Unexpectedly, an in#uence of surface texture on the deposition rate was observed, although all tube surfaces were hydraulically smooth. This could be explained by a di!usion process

Etat de l'art de la mesure de l'efficacité des Appareils de Protection Respiratoire et description d'un nouveau banc de test des APR dédié aux nanoparticules

National audienceLes particules de taille nanométrique pourraient représenter un risque de plus en plus important pour la santé des travailleurs du fait du fort développement des nanotechnologies. Lorsqu'il n'est pas possible de réduire le risque à la source, l'Appareil de Protection Respiratoire filtrant (APR) est un des moyens utilisés pour réduire l'exposition à certaines substances nocives, dont les particules. L'objectif de notre étude est de déterminer si ces appareils sont performants pour des particules de taille nanométrique. Nous présenterons ici l'APR sélectionné pour ce travail, un demi-masque bi-filtres du fabricant Sperian. Une étude bibliographique sur l'efficacité de filtration des APR est aussi exposée. Celle-ci a mis en évidence qu'aucune étude n'a été consacrée à l'efficacité d'un demi-masque pour des particules ultrafines et que peu d'études ont été effectuées sur l'efficacité de filtration en simulant la respiration humaine. Nous présenterons en dernière partie le banc de test que nous avons conçu dans notre étude. Celui-ci est élaboré autour d'une tête normalisée et d'un appareil de simulation respiratoire. Il permettra d'intégrer l'influence des cycles respiratoires dans la détermination de l'efficacité d'un APR pour des nanoparticules

What we can learn from measurements of air electric conductivity in ²²²Rn-rich atmosphere

International audienceElectric conductivity of air is an important characteristic of the electric properties of an atmosphere. Testing instruments to measure electric conductivity ranging from ~10-13 to 10-9 S m-1 in natural conditions found in the Earth atmosphere is not an easy task. One possibility is to use stratospheric balloon flights; another (and a simpler one) is to look for terrestrial environments with significant radioactive decay. In this paper we present measurements carried out with different types of Conductivity Sensors in two 222Rn-rich environments, i.e. in the Roselend underground tunnel (French Alps) and in the IRSN BACCARA chamber. The concept of the Conductivity Sensor is based on the classical time relaxation method. New elements in our design include isolation of the sensor sensitive part (electrode) from the external electric field and sensor miniaturization. This greatly extends the application domain of the sensor and permits to measure air electric conductivity when the external electric field is high and varies from few tens of V m-1 to up to few tens of kV m-1. This is suitable to propose the instrument for a planetary mission. Two-fold objectives were attained as the outcome of these tests and their analysis. First was directly related to the performances of the Conductivity Sensors and the efficiency of the Conductivity Sensor design to shield the external electric field. Second objective aimed at understanding the decay mechanisms of 222Rn and its progeny in atmosphere and the impact of the enclosed space on the efficiency of gas ionization. This article is protected by copyright. All rights reserved

An interactive e-learning module to promote bio-psycho-social management of low back pain in healthcare professionals : a pilot study

INTRODUCTION: Low back pain (LBP) is ranked as the first musculoskeletal disorder considering years lived with disability worldwide. Despite numerous guidelines promoting a bio-psycho-social (BPS) approach in the management of patients with LBP, many health care professionals (HCPs) still manage LBP patients mainly from a biomedical point of view. OBJECTIVE: The purpose of this pilot study was to evaluate the feasibility of implementing an interactive e-learning module on the management of LBP in HCPs. METHODS: n total 22 HCPs evaluated the feasibility of the e-learning module with a questionnaire and open questions. Participants filled in the Back Pain Attitude Questionnaire (Back-PAQ) before and after completing the module to evaluate their attitudes and beliefs about LBP. RESULTS: The module was structured and easy to complete (91%) and met the expectations of the participants (86%). A majority agreed that the module improved their knowledge (69%). Some participants (77%) identified specific topics that might be discussed in more detail in the module. HCPs knowledge, beliefs and attitudes about LBP significantly improved following module completion (t = −7.63, P < .001) with a very large effect size (d(s) = −1.63). CONCLUSION: I The module seems promising to change knowledge, attitudes and beliefs of the participants. There is an urgent need to develop and investigate the effect of educational interventions to favor best practice in LBP management and this type of e-learning support could promote the transition from a biomedical to a bio-psycho-social management of LBP in HCPs

Clinimetric properties of the Dutch translation of the back pain attitude questionnaire BACK-PAQ

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