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Indoor radon source potential from unground soil was monitored using prototype devices approaching a dwelling with a cellar basement at 1 depth from the soil-atmosphere interface. Therefore, the radon concentrations in soil gas were monitored at 1 m depth. Integrated radon measurements were performed, and the results correlated with meteorological parameters. The influence of the difference in outdoor and device-soil temperature was considered, and the infiltration rate was calculated. The effect of the soil temperature gradient on the soil radon entry rate was evaluated. The indoor radon entry rate due to the soil gas was 7.0 ± 2.7 Bq m -3  h -1 . The radon entry rate was 5.0 ± 0.8 Bq m -3  h -1 due to diffusion. In contrast, the advection-drive flow of soil gas is ranged up to ± 4.0 Bq m -3  h -1 . So, the infiltration rate of the model dwelling was 0.7 (± 0.5) × 10 -1  h -1 if only the stack effect occurred. The radon levels in tap water were measured, and the radon entry rate was estimated at 1.3 ± 0.7 Bq m -3  h -1 . If the ventilation rate is low or seismic faulting appears, the soil radon entry is increased by one order of magnitude. The soil radon appeared like the building materials, having 1/3 of the total indoor radon entry, while outdoor air was slightly lower (28%), with tap water at 5%. The resident's mortality risk occurred at < 2.5% for typical dwellings in temperate climate areas founded on sand-gravel underground. The risk rises to 34% with an extremely low ventilation rate between indoors and outdoors or high radon entry from the soil due to seismic faulting., (© 2024. The Author(s).)

Radon and Rn progenies' concentrations were determined in the urban polluted atmosphere of Thessaloniki's city center using two experimental procedures: (i) filter with 0.8-μm porosity measured using α-counting technique determining the radon equilibrium equivalent concentration (C EER ), which varies from 2.6 to 8.9 Bq m -3 , and (ii) filter with 0.3-μm porosity measured in the laboratory using γ-spectrometry determining 214 Pb activity concentration 1.3-7.5 Bq m -3 and 214 Bi activity 3.1-11.5 Bq m -3 . Strong daily correlation with the relative humidity is presented, in association to an inverse correlation with the temperature gradient. Radon and its daughter's concentration correlate well smoke particles' content because radon is trapped inside them due to their high effective porosity, and so the Rn daughter collection in the filter increases. Gas pollutants have similar daily distribution with the radon activity, while SO 2 levels are correlated the best with 214 Pb and 214 Bi concentrations, as Pb is more chemically associated to sulfuric complex ions than nitric formation in presence of vapors. The lower 214 Pb/ 214 Bi activity ratio appeared during the highest temperature gradient and amount of vapors, smoke, and gases giving rise to high formation of ultrafine aerosol particles. The ultrafine aerosol creation boosts 214 Pb recoil effect taken place during 218 Po α-decay, so 214 Pb nuclei become free starting the clustering process yet again having ingrowth coefficient ~ 0.1 nm 2 s -1 regarding accumulation mode aerosols.

Two methods for radon emanation factor determination were performed and compared regarding their measuring accuracy: (a) by hermetically closing the sample in an airtight container and measuring the induced radon activity, and (b) by mixing charcoal and sealing the sample hermetically and after placing the sample in an open vessel with no charcoal addition, measuring each time the 226Ra content using gamma-spectrometry. Measurements of radon emanation factor of cement and pozzolanic additives, i.e. fly ash and phosphogypsum were also performed.

In controlling the natural radiation exposure for the residents of dwellings, it is necessary to determine the levels of natural radioactivity (external exposure) and radon exhalation rate (internal exposure) from building materials. Using a high-resolution gamma ray spectrometry system, the activity concentration of natural radionuclides was measured. The radon exhalation rate was measured by hermetically closing the sample in a container and following the radon activity growth as a function of time. Three different methods were applied in order to find the most appropriate, i.e. that with the less uncertainty for the less exposure time. Typical building materials were analyzed in order to examine the external and internal exposures. In addition, the total annual effective dose was evaluated for the residents of a typical Greek dwelling.

Radon concentrations indoors were determined in 24 typical occupied apartments in the city of Thessaloniki, North Greece (40 degrees 38'N, 22 degrees 58'E), by means of 12 surveys, each 2 mo long, over a 2-y period starting October 1989. The ratio of the winter and summer averages for the first year of measurements was 1.8 +/- 0.78, and for the second year of measurements was 1.6 +/- 0.61. The indoor radon concentration in the summer (1990) period ranged between 8 and 81 Bq m-3, while in the winter (1989-1990) it ranged between 20 and 143 Bq m-3 for the first year of measurements or between 8 and 92 Bq m-3 in the summer (1991) period and between 12 and 119 Bq m-3 in the winter (1990-1991) for the second year of measurements. These results were obtained by type CN-85 alpha track detectors. Some parameters that influenced the concentrations, such as precipitation rates and use of fly ash in building materials, are discussed.

The 238U, 226Ra, 210Pb, 228Ra, 228Th and 40K concentrations have been measured beside to radon emanation factor due to sample granulometric using γ-spectrometry. The radiological hazards of zeolitic rocks application in the environment as soil improvements, diet supplements and building materials have been studied. No γ-radiation hazards occur for soil improvements since up to 0.13 mSv year−1 estimate. No radiation hazards arise for diet supplements since 0.21 μSv day−1 g−1 of zeolite intake is estimated. Instead, the application as cement and bricks give external annual effective dose up to 1.19 mSv, while the internal radiation rises to 3.45 mSv. [ABSTRACT FROM AUTHOR]

Radon concentration measurements were carried out using solid-state nuclear track-etch detectors (SSNTDs) type CA 80-15 cellulose nitrate films, in a Pleistocenic cave at Petralona, in Halkidiki, Northern Greece, at 55 km from the city of Thessaloniki. Radon levels as high as 88 kBq.m-3 (2.38 nCi.l-1) have been recorded inside the cave equivalent to 11.90 WL in terms of occupational exposure to radon and its decay products. Absorbed dose rates were performed using TL dosimeters, type TLD-200 (CaF2-Dy) in a continuous monitoring program (integrated measurements). Dose rate levels as high as 110 nGy.h-1 were recorded inside the cave. In interpreting the high levels of radiation doses, radioactivity measurements regarding the naturally occurring 238U, 232Th and 40K radionuclides were carried out in various speleothems found at different sites in the cave. [ABSTRACT FROM AUTHOR]