Seasonal Variation of Radon Concentrations in Russian Residential High-Rise Buildings

Ra-226 in building materials as a source of indoor radon in high-rise residential buildings in Russian cities

The problem of indoor radon in high-rise buildings is mostly associated with exhalation from building materials. Characterization of the radon entry from building materials by diffusion is required to provide a proper control of the population indoor radon exposure. To analyze the relationship between the content of Ra-226 in building materials and the indoor radon concentration the results of the following surveys in high-rise buildings in Russian cities were used: 1) indoor radon (>1000 apartments), 2) natural radionuclides in the building materials in existing buildings by means of non-destructive field gamma spectrometry (100 apartments). The surveys were carried out in nine large cities in different climatic zones. The radon entry rate due to diffusion from building materials, D, normalized to Ra-226 activity concentration, Ra, is in the range of 0.2-0.6 (Bq/m3/h)/(Bq/kg), depending on the type of building materials and building construction. In new multi-story buildings, the typical D/Ra ratio can be assumed to be 0.4 (Bq/m3/h)/(Bq/kg). In new energy-efficient buildings, the ratio of the radon concentration to Ra-226 activity concentration is on average 2.1 times higher than in multi-story buildings of lower energy efficiency built before 2000. The average radon exhalation rate from the building materials, normalized to Ra-226 activity concentration, is estimated to be 0.25 Bq/m2/h.

Relationship between Ra-226 activity concentration in building materials and indoor radon concentration: An example of Russian high-rise residential buildings

The worldwide trend toward the construction of high-rise buildings with high energy efficiency highlights the role of building materials as a source of indoor radon in the modern urban environment. The aim of the study is to analyze the relationship between the Ra-226 activity concentration in building materials and indoor radon concentration using the example of multi-story buildings in Ekaterinburg. Measurements of the activity concentration of natural radionuclides in building materials were carried out using a new non-destructive method. A radon survey conducted early provided the data on indoor radon concentrations in the same apartments. The obtained Ra-226 activity concentrations in building materials in high-rise buildings were found to be relatively low, ranging from 9.1 to 51 Bq/kg. The typical radon entry rate by diffusion from building materials for modern Russian multi-story buildings can be accepted as equal to 0.5 Bq/(m3∙h) per 1 Bq/kg of Ra-226 activity concentration. Ra-226 in building materials has been shown to be a primary source of indoor radon in modern high-rise buildings, where this factor can cause indoor radon concentrations above the reference level of 100 Bq/m3 at low air exchange rates. The activity concentration of Ra-226 in building materials should be considered a separate parameter for regulation within the national radiation protection systems.

Radon mapping, correlation study of radium, seasonal indoor radon and radon exhalation levels in communities around Ghana atomic energy commission

Radon mapping and seasonal radon studies have been carried out within the communities around the Ghana Atomic Energy Commission (GAEC), using ArcMap geostatistical interpolation tool. The correlation analysis was done using Pearson's correlation tools. Average seasonal indoor radon variations for CR (rainy) and CD (dry) with mean values ranging from 28.9 to 177.2 Bq/m3 (78.1 ± 38.7 Bq/m3) and 24.4-125.5 Bq/m3 (69.9 ± 24.2 Bq/m3). Average seasonal soil radon exhalation for ER (rainy) and ED (dry) with mean values ranging from 39.6 to 100.3 (68.9 ± 24.2 μBq/m2 h) and 55.2 to 111.9 (77.1 ± 18.7 μBq/m2 h). Radium concentrations ranged from 8.1 to 42.2 Bq/kg (21.3 ± 9.9 Bq/kg). Annual effective dose and resultant effective dose to lungs were found to be 0.9 to 2.9 (1.9 ± 0.8 mSv/yr), 2.1 to 9.2 (4.6 mSv/yr). The study recorded the highest and lowest positive correlation coefficient was found in the study with higher and lower coefficient values of 0.81 and 0.47 recorded in radium concentration with radon exhalation and indoor radon concentration within the dry season respectively. Pearson correlation result recorded values 0.81 and 0.47 as the highest and lowest positive coefficient values for the radium concentration correlation between radon exhalation and indoor radon concentration. One directional principal component was observed in radium concentration, seasonal radon exhalation, and indoor radon concentration. Two clusters originated from radium and seasonal radon concentrations present in dwellings as well as soils. Pearson's correlation results were in agreed with the principal component and cluster factor analysis. The study obtained the highest and lowest indoor radon concentrations with radon exhalation in rainy and dry seasons. Radium concentration was found to have a considerable effect on indoor radon and radon exhalation in dwellings and soils.

Gini Method Application: Indoor Radon Survey in Kpong, Ghana

In this study, the indoor radon concentrations map, starting from a sparse measurements survey, was realized with the Gini index method. This method was applied on a real dataset coming from indoor radon measurements carried out in Kpong, Ghana. The Gini coefficient variogram is shown to be a good estimator of the inhomogeneity degree of radon concentration because it allows for better constraining of the critical distance below which the radon geological source can be considered as uniform. The indoor radon measurements were performed in 96 dwellings in Kpong, Ghana. The data showed that 84% of the residences monitored had radon levels below 100 Bqm−3, versus 16% having levels above the World Health Organization’s (WHO) suggested reference range (100 Bqm−3). The survey indicated that the average indoor radon concentration (IRC) was 55 ± 36 Bqm−3. The concentrations range from 4–176 Bqm−3. The mean value 55 Bqm−3 is 38% higher than the world’s average IRC of 40 Bqm−3 (UNSCEAR, 1993).

Editorial for the Special Issue “Atmospheric Radon Measurements, Control, Mitigation and Management”

 The Special Issue of the open-access journal Atmosphere addresses the issue of “Atmospheric Radon Measurements, Control, Mitigation and Management”, based on the global need for better management of radon and indoor air pollutants inside buildings, based on reliable research experience. [...]