Variation of indoor radon concentration and ambient dose equivalent rate in different outdoor and indoor environments

Abstract

Subject of this study is an investigation of the variations of indoor radon concentration and ambient dose equivalent rate in outdoor and indoor environments of 40 dwellings, 31 elementary schools and five kindergartens. The buildings are located in three municipalities of two, geologically different, areas of the Republic of Macedonia. Indoor radon concentrations were measured by nuclear track detectors, deployed in the most occupied room of the building, between June 2013 and May 2014. During the deploying campaign, indoor and outdoor ambient dose equivalent rates were measured simultaneously at the same location. It appeared that the measured values varied from 22 to 990 Bq/m(3) for indoor radon concentrations, from 50 to 195 nSv/h for outdoor ambient dose equivalent rates, and from 38 to 184 nSv/h for indoor ambient dose equivalent rates. The geometric mean value of indoor to outdoor ambient dose equivalent rates was found to be 0.88, i.e. the outdoor ambient dose equivalent rates were on average higher than the indoor ambient dose equivalent rates. All measured can reasonably well be described by log-normal distributions. A detailed statistical analysis of factors which influence the measured quantities is reported.

Results of radon CR-39 detectors exposed in schools due two different long-term periods

“…In both cases, the coeffi cient of variation and geometric standard deviation have high values. The reasons for dispersions between schools are the variability of the factors that controls indoor Rn, namely the geogenic Rn potential (different geological base) and building characteristics in terms of Rn infi ltration and accumulation [4]. Furthermore, the results from both detectors have about the same distribution (Fig.…”

“…The estimated values of the relative combined uncertainty of individual results in this study, which include uncertainties of track counting, time, calibration factor, and the detector background, were in the range 11 to 19%. This type of detector is also used in other scientifi c research [3,4].…”

Results of Indoor Radon Measurements in the Republic of Macedonia: – A Review –

“…The results of annual CRn measurements in schools, dwellings and kindergartens were not different (Stojanovska et al, 2016a). There are also no differences between the results of CRn in schools when they are based on the annual measurements (12 months) and when they are in the period exempt from the summer holiday (9 months) (Stojanovska et al, 2016b).…”

“…The analysis showed that the CRn in buildings with new windows was twice higher in comparison to CRn in buildings with wooden windows (GM = 110 (2.13) Bq/m 3 ). In the same survey, the environmental impact on CRn was examined, but it turned out that there was no difference between urban and rural areas (Stojanovska et al 2016a).…”

Temporal and spatial variations of ambient dose equivalent rate in urban and rural sites

“…The higher levels of background radiation are associated with volcanic rock masses (granite), and lower levels with sedimentary rocks (Stojanovska et al, 2016;Abba et al, 2017) and Quaternary geological background (Sanusi et al, 2014).…”