Thoron, radon and air ions spatial distribution in indoor air.

Spatial distribution of radioactive gasses thoron (Tn) and radon (Rn) in indoor air of 9 houses mostly during winter period of 2013 has been studied. According to properties of alpha decay of both elements, air ionization was also measured. Simultaneous continual measurements using three Rn/Tn and three air-ion active instruments deployed on to three different distances from the wall surface have shown various outcomes. It has turned out that Tn and air ions concentrations decrease with the distance increase, while Rn remained uniformly distributed. Exponential fittings function for Tn variation with distance was used for the diffusion length and constant as well as the exhalation rate determination. The obtained values were similar with experimental data reported in the literature. Concentrations of air ions were found to be in relation with Rn and obvious, but to a lesser extent, with Tn.

The potential health hazard due to elevated radioactivity in old uranium mines in Dolina Bialego, Tatra Mountains, Poland.

Natural radioactivity is one of the essential components of the environment. Unlike the Sudety mountains area in Poland, the Tatra Mountains were not the subject of wide survey as regards the levels of natural radioactivity. Especially, the concentrations of radon (natural radioactive gas) have not been investigated there in terms of their possible negative health impact. Within the frame of bilateral cooperation between the Institute of Nuclear Physics in Kraków, Poland, and the Jozef Stefan Institute in Ljubljana, Slovenia, the measurements of natural radioactive elements in old uranium mines in the Tatra National Park were performed in June 2010. The investigated sites were located in Dolina Bialego (The Valley of the White). One of the mines is situated near the tourist path. The paper presents the results of complex measurements of natural radioactivity in both uranium drifts. The concentration of radon gas inside the mining drifts exceeded 28,000 Bq m(-3). Also, very high gamma dose rates were observed (up to 5600 nSv h(-1)). The maximum concentrations of natural radioactive elements (potassium (40)K, radium (226)Ra, thorium (232)Th) in rock samples amounted to 535, 2137, and 18 Bq kg(-1), respectively. The effective dose rates due to radon and thoron inhalation have been assessed as 0.013 mSv h(-1) (for the lowest concentration) and 0.121 mSv h(-1) (for the highest concentration).

Tracing the sources of gaseous components (222Rn, CO2 and its carbon isotopes) in soil air under a cool-deciduous stand in Sapporo, Japan.

Radon ((222)Rn) and carbon dioxide were monitored simultaneously in soil air under a cool-temperate deciduous stand on the campus of Hokkaido University, Sapporo, Japan. Both (222)Rn and CO(2) concentrations in soil air varied with atmospheric (soil) temperature in three seasons, except for winter when the temperature in soil air remained constant at 2-3 degrees C at depth of 80 cm. In winter, the gaseous components were influenced by low-pressure region passing through the observation site when the ground surface was covered with snow of ~1 m thickness. Carbon isotopic analyses of CO(2) suggested that CO(2) in soil air may result from mixing of atmospheric air and soil components of different origins, i.e. CO(2) from contemporary soil organic matter and old carbon from deeper source, to varying degrees, depending on seasonal meteorological and thus biological conditions.

Meteorological parameters contributing to variability in 222Rn activity concentrations in soil gas at a site in Sapporo, Japan.

Continuous (222)Rn monitoring in soil gas since November 22, 2004 has revealed variability in activity concentration with time in the semi-natural woods on the campus of Hokkaido University in Sapporo, Japan. Among various factors affecting soil radon levels and variability, temperature was found to be dominant during three seasons when activity concentrations of (222)Rn showed a diurnal high and nocturnal low with a boundary around 10 o'clock in the morning. This pattern was disturbed by low pressure fronts with occasional rain. The activity gradually decreased as soil temperatures decreased from late November to mid-December. After the ground surface was completely covered with snow, soil radon levels became low with a small fluctuation. There were several peaks of (222)Rn on the time-series chart in winter. Those peaks appearing in early winter and early spring may be interpreted by considering meteorological parameters. In a few cases, the radon activity suddenly increased with increasing pressure in the soil at a depth of 10 cm, which may be associated with subsurface events such as seismic activity in the area.

Indoor air radon concentration in schools in Prizren, Kosovo.

Indoor air radon ((222)Rn) concentrations were measured in spring and winter in 30 rooms of 9 elementary schools and 19 rooms of 6 high schools in Prizren, Kosovo, using alpha scintillation cells. Only in three rooms of elementary schools and four rooms of high schools did winter concentrations exceed 400 Bq m(-3).

Radon survey and exposure assessment in hospitals.

In this study radon (222Rn) in indoor air was surveyed in 201 rooms of 26 major hospitals in Slovenia and annual effective doses for 1025 persons working in the rooms surveyed were estimated. Instantaneous radon concentrations were measured with alpha scintillation cells, long-term average concentrations with etched track detectors and electret detectors, and radon, its progeny and equilibrium factor were continuously recorded with portable devices. Effective doses were estimated by using ICRP Publication 65 methodology. Only in seven rooms did the average radon concentration, obtained by 1 month exposing etched track detectors, exceed the national limit of 400 Bq m-3; and these places will be mitigated; elsewhere it was lower. Annual effective doses for 966 persons (94.2%) were estimated as <1 mSv, but for 10 persons they were between 2.1 and 7.3 mSv. The results warn that in an environment with generally low radon levels, 'hot' points may be found, and therefore radon surveys should be carefully designed and performed in order not to miss them.

Inclined N2 desorption in a steady-state N2O + CO reaction on Pd(110).

The angular and velocity distributions of desorbing products were analyzed in the course of a catalyzed N2O + CO reaction on Pd(110). The reaction proceeded steadily above 450 K, and the N2 desorption merely collimated sharply along 45 degrees off the surface normal toward the [001] direction. It is proposed that this peculiar N2 desorption is induced by the decomposition of adsorbed N2O oriented along the [001] direction. On the basis of the observation of similar inclined N2 desorption in both NO + CO and N2O + CO reactions, the N2 formation via the intermediate N2Oa dissociation was confirmed in catalytic NO reduction.