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The requirements about radon measurements in schools and public buildings included in most of the national and international legislations are generally restricted to all the rooms located at the ground floor and basement, assuming the soil beneath the building as the main source of indoor radon. In order to verify such an assumption for small buildings having at maximum two floors, a preliminary study was performed in 50 schools located in 15 municipalities of the Republic of Srpska. Results of this study suggest that a protocol requiring measurements at the ground floor only may be considered adequate. Due to the high radon spatial variability for rooms at the ground floor, it is preferable to require measurements in a high number of rooms (preferably in all of them) in order to assess the compliance with the reference level established by the legislation.

In this work we explore the relationship between particulate matter (PM) and small ion (SI) concentration in a typical indoor elementary school environment. A range of important air quality parameters (radon, PM, SI, temperature, humidity) were measured in two elementary schools located in urban background and suburban area in Belgrade city, Serbia. We focus on an interplay between concentrations of radon, small ions (SI) and particulate matter (PM) and for this purpose, we utilize two approaches. The first approach is based on a balance equation which is used to derive approximate relation between concentration of small ions and particulate matter. The form of the obtained relation suggests physics based linear regression modelling. The second approach is more data driven and utilizes machine learning techniques, and in this approach, we develop a more complex statistical model. This paper attempts to put together these two methods into a practical statistical modelling approach that would be more useful than either approach alone. The artificial neural network model enabled prediction of small ion concentration based on radon and particulate matter measurements. Models achieved median absolute error of about 40 ions/cm3 and explained variance of about 0.7. This could potentially enable more simple measurement campaigns, where a smaller number of parameters would be measured, but still allowing for similar insights. © 2020 by the authors.

The main contribution to population exposure is due to radon and thoron progenies and not radon itself. The aim of this study was therefore to estimate annual effective dose using the results of Direct Radon and Thoron Progeny Sensors were exposed in 69 selected schools and 319 dwellings in several regions of Balkans: in Serbia: regions of Sokobanja and Kosovo and Metohija, Republic of Macedonia, Republic of Srpska and Slovenia. Obtained average total effective doses are in the range from 0.22 mSv a-1 (schools in Republic of Srpska) to 2.5 mSv a-1 (dwellings in Kosovo) and are below the reference level of 10 mSv a-1 recommended by International Commission on Radiological Protection. © The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The subject of this study is the radon concentrations variations, measured with a nuclear track detectors in a total of 58 premises in all 29 primary schools of 4 municipalities in the Eastern part of the Republic of Macedonia. Despite a relatively small territory, the variability of radon concentrations proved to be significant. The geometric means (geometric standard deviations) of radon concentrations in the examined municipalities were in the range from GM = 71 Bq/m 3 (GSD = 2.08) to GM = 162 Bq/m 3 (GSD = 2.69), while for the entire region it was: GM = 96 Bq/m 3 (GSD = 2.47). The influence of the geographical and geological features of the school site as well as the building characteristics on the radon variations were investigated. The analysis showed that type of municipality, building materials, basement and geology have significant effects and respectively describe 6%, 16%, 22%, 39% of the radon total variability.

It is indicated that the exposure to radon originating from the building materials is not negligible and the radon exhalation measurement should get more attention in the future. The experience with four different methods of the exhalation measurement, established in our laboratory for the purpose of the intercomparison is reported. Additionally, a comparison of advantages and disadvantages of used methods is discussed.

UV zračenje se u Srbiji meri nezavisno u Beogradu i Novom sadu već duži niz godina. Radi bolje informisanosti stanovništva ova merenja su kroz projekat nevladinih organizacija pod nazivom „Ozonizacija“ objedinjena i uniformisana te su sada svima dostupna preko sajta http://www.uv-srbija.rs i aplikacije za android mobilne telefone „UV indeks Srbija“. Podaci Indeksa UV zračenja se obnavljaju na svakih pola sata dok se podaci za koncentraciju stratosferskog ozona iznad novog sada odnosno Srbije daju dnevno. Vrednosti UV indeksa se prikazuju grafički, a na sajtu je dato detaljno objašnjenje o tome šta UV indeks predstavlja, koje su vrednosti opasne, kako se zaštititi od preteranog izlaganja Sunčevom zračenju i kako se proračunava faktor zaštite (SPF) krema za sunčanje., UV radiation in Serbia is measured independently in Belgrade and Novi Sad for many years. For better public information, these measurements are unified and uniformed through the project of non-governmental organizations named "Ozonisation", and are now available on the website http://www.uv-srbija.rs and applications for Android mobile phones “UV index Serbia”. Data of UV Index are updated every half hour, while the data for the concentration of stratospheric ozone above the Novi Sad, i.e. Serbia, are given daily. The UV index values are displayed graphically, and the site provides a detailed explanation of what the UV index represents, which index values are dangerous, how to protect against excessive exposure to sunlight, and how the sun protection factor (SPF) is calculated.

Prikazan je pregled najnovijeg gama metoda za merenje ekshalacije radona iz građevinskih materijala, koji pored ekshalacije omogućava merenje faktora emanacije i merenje difuzione dužine radona u datom materijalu, što nije moguće u standardnim merenjima ekshalacije radona. Takođe su prikazana i još tri standardna metoda merenja ekshalacije radona i dato je uporedno objašnjene prednosti i mana ovih metoda. Biće dat i pregled dosadašnjih merenja u Srbiji., A review of a new radon exhalation measurement method is presented. This method provides also a measurement of the radon diffusion length and the radon emanation coefficient, which is not possible by standard radon exhalation measurement methods. Besides, three standard radon exhalation measurements are presented: closed chamber with an active instrument, closed chamber with a solid state nuclear track detector and a charcoal canister method. An intercomparison of advantages and disadvantages is also given. A short review of previous measurements of radon exhalation from comercial building materials in Serbia will be given in the presentation.

We present a method for the estimation of annual radon concentration based on short-term (three months) measurements. The study involves results from two independent sets of indoor radon concentration measurements performed in 16 cities of the Republic of Macedonia. The first data set contains winter and annual radon concentration obtained during the National survey in 2010 and the second, contains only the radon concentration measured during the winter of 2013. Both data sets pertain to radon concentration from the same cities and have been measured applying the same methodology in ground floor dwellings. The results appeared to be consistent and the dispersion of radon concentration was low. Linear regression analysis of the radon concentration measured in winter of 2010 and of the 2010 annual radon concentration revealed a high coefficient of determination R-2 = 0.92, with a relative uncertainty of 3%. Furthermore, this model was used to estimate the annual radon concentration solely from winter-term measurements performed in 2013. The geometrical mean of the estimated annual radon concentration of the 2013: radon concentration (A-2013) =98 Bqm(-3) was almost equal to the geometrical mean of the annual radon concentration from the 2010, radon concentration (A-2010) = 99 Bqm(-3). Analysis of the influence of building characteristics, such as presence/absence of a basement in the building, or the dominant building material on the estimated annual radon concentration is also reported. Our results show that a low number of relatively short-term radon measurements may produce a reasonable insight into a gross average obtained in a larger survey.

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/an 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. (C) 2016 Elsevier Ltd. All rights reserved.

With an increase in the awareness of the need to save energy, residents tend to live in dwellings with increasingly tight windows and doors, thus reducing the ventilation rate of indoor air which leads to an increased accumulation of radon indoors. Having in mind that a dose from an exposure to inhaled radon and its progenies can be higher than a dose received from radium in building materials, it is suggested that radon exhalation measurements should receive due attention. In this contribution, the authors compare results gathered using a few methods for radon exhalation measurement and discuss its merits and demerits.

In the era of the energy saving policy (i.e. more air tight doors and windows), the radon exhaled from building materials tends to increase its concentration in indoor air, which increases the importance of the measurement of radon exhalation from building materials. This manuscript presents a novel method of the radon exhalation measurement using only a HPGe detector or any other gamma spectrometer. Comparing it with the already used methods of radon exhalation measurements, this method provides the measurement of the emanation coefficient, the radon diffusion length and the radon exhalation rate, all within the same measurement, which additionally defines materials radon protective properties. Furthermore it does not necessitate additional equipment for radon or radon exhalation measurement, which simplifies measurement technique, and thus potentially facilitates introduction of legal obligation for radon exhalation determination in building materials. (C) 2016 Elsevier Ltd. All rights reserved.

Concentration and size distribution of airborne particles (size range 10-1100 nm), using a SMPS+C Scanning Mobility Particle Sizer, and concentrations of positive and negative cluster ions (size range 0.36-1.6 nm), using several CDI-06 Gerdien-type integral air ion detectors, have been monitored in three rooms in rural dwellings of Serbia and Slovenia, during periods when nobody was present in the room and while smoking and heating were taking place. The highest particle generation rate was 2.4 x 10(11) min(-1) while cigarette smoking was taking place and was 1.5 x 10(11) min(-1) during heating with a cast iron stove with wood burning at 150 degrees C, and 1.1 x 10(10) min(-1), during heating with an Alpine -type oven at 40-50 degrees C. The related particle loss rate constants were 0.0603 min(-1), 0.0442 min(-1), and 0.0067 min(-1). The estimated mean values of the effective ion attachment rate beta(eff) vary between (2.2-5.4)10(-6) cm(3) s(-1). A correlation between ions concentration and particles concentration and their sizes has been sought, and findings are discussed and shown. (C) 2016 Elsevier Ltd. All rights reserved.

This article reports results of the first investigations on indoor radon, thoron and their decay products concentration in 25 primary schools of Banja Luka, capital city of Republic Srpska. The measurements have been carried out in the period from May 2011 to April 2012 using 3 types of commercially available nuclear track detectors, named: long-term radon monitor (GAMMA 1)- for radon concentration measurements (C-Rn); radon-thoron discriminative monitor (RADUET) for thoron concentration measurements (C-Tn); while equilibrium equivalent radon concentration (EERC) and equilibrium equivalent thoron concentrations (EETC) measured by Direct Radon Progeny Sensors/Direct Thoron Progeny Sensors (DRPS/DTPS) were exposed in the period November 2011 to April 2012. In each school the detectors were deployed at 10 cm distance from the wall. The obtained geometric mean concentrations were C-Rn = 99 Bq m(-3) and C-Tn = 51 Bq m(-3) for radon and thoron gases respectively. Those for equilibrium equivalent radon concentration (EERC) and equilibrium equivalent thoron concentrations (EETC) were 11.2 Bq m(-3) and 0.4 Bq m(-3), respectively. The correlation analyses showed weak relation only between C-Rn and C-Tn as well as between C-Tn and EETC. The influence of the school geographical locations and factors linked to buildings characteristic in relation to measured concentrations were tested. The geographical location and floor level significantly influence C-Rn while C-Tn depend only from building materials (ANOVA, p LT = 0.05). The obtained geometric mean values of the equilibrium factors were 0.123 for radon and 0.008 for thoron. (C) 2015 Elsevier Ltd. All rights reserved.

Radon concentration measurements were performed in all 25 primary schools in Banja Luka city, the capital of Republic of Srpska, during 2011 and 2012, using both active RAD7 continual radon measuring instruments and CR-39 passive (commercially known as Gamma) detectors. The two complimentary methods were employed not only to obtain annual averages, but also to study the dynamics of radon concentration changes during the week. For each school, average and temporal variations of radon concentrations were analysed, taking into consideration local geology, building materials and meteorological conditions. The influence of forced ventilation, caused by frequent opening of doors and windows during working hours, with typical dawn and weekend peaks is evident in most but not all schools. Elevated levels of radon concentration ( GT 400 Bq m(-3)) were found in a few schools using both methods. Although high correlation factor of 0.8 between passive and active methods was found, still short-time (one-week) measurements cannot be used for annual estimation of radon activity but only as a screening one. Thus, the conclusion concerns only long time measurements as valid indicator of annual radon activity.