Novel approach to analysing large data sets of personal sun exposure measurements

Personal sun exposure measurements provide important information to guide the development of sun awareness and disease prevention campaigns. We assess the scaling properties of personal ultraviolet radiation (pUVR) sun exposure measurements using the wavelet transform (WT) spectral analysis to process long-range, high-frequency personal recordings collected by electronic UVR dosimeters designed to measure erythemal UVR exposure. We analysed the sun exposure recordings of school children, farmers, marathon runners and outdoor workers in South Africa, and construction workers and work site supervisors in New Zealand. We found scaling behaviour in all the analysed pUVR data sets. We found that the observed scaling changes from uncorrelated to long-range correlated with increasing duration of sun exposure. Peaks in the WT spectra that we found suggest the existence of characteristic times in sun exposure behaviour that were to some extent universal across our data set. Our study also showed that WT measures enable group classification, as well as distinction between individual UVR exposures, otherwise unattainable by conventional statistical methods

European Atlas of Natural Radiation

Natural ionizing radiation is considered as the largest contributor to the collective effective dose received by the world population. The human population is continuously exposed to ionizing radiation from several natural sources that can be classified into two broad categories: high-energy cosmic rays incident on the Earth’s atmosphere and releasing secondary radiation (cosmic contribution); and radioactive nuclides generated during the formation of the Earth and still present in the Earth’s crust (terrestrial contribution). Terrestrial radioactivity is mostly produced by the uranium and thorium radioactive families together with potassium. In most circumstances, radon, a noble gas produced in the radioactive decay of uranium, is the most important contributor to the total dose. This Atlas aims to present the current state of knowledge of natural radioactivity, by giving general background information, and describing its various sources. This reference material is complemented by a collection of maps of Europe displaying the levels of natural radioactivity caused by different sources. It is a compilation of contributions and reviews received from more than 80 experts in their field: they come from universities, research centres, national and European authorities and international organizations. This Atlas provides reference material and makes harmonized datasets available to the scientific community and national competent authorities. In parallel, this Atlas may serve as a tool for the public to: • familiarize itself with natural radioactivity; • be informed about the levels of natural radioactivity caused by different sources; • have a more balanced view of the annual dose received by the world population, to which natural radioactivity is the largest contributor; • and make direct comparisons between doses from natural sources of ionizing radiation and those from man-made (artificial) ones, hence to better understand the latter.JRC.G.10-Knowledge for Nuclear Security and Safet

Wavelet spectral analysis of teleconnection indices and activities of beryllium-7 and lead-210 in ground level air in Belgrade, Serbia

Activities of beryllium-7 and lead-210 are monitored in ground level air in Belgrade, Serbia. The measuring sites are located at the Institute of Nuclear Sciences Vinča. The activities are determined on HPGe detectors by standard gamma spectrometry. Five teleconnection indices of large scale atmospheric circulation: North Atlantic Oscillation, East Atlantic Pattern, East Atlantic/West Russia Pattern, Scandinavia Pattern, and Polar/Eurasia Pattern are obtained from the data archive of the United States National Oceanic and Atmospheric Administration's Climate Prediction Center. The collected time series consist of monthly values and span more than two decades: beryllium-7 since 1991, lead-210 since 1985, and the teleconnection indices since 1950, thus offering data arrays of sufficient lengths for wavelet spectral analysis. A relation between the radionuclides' activities and the indices is first investigated using Pearson's correlation coefficients. The computed coefficients do not indicate a linear relationship between the variables. However, the wavelet spectral analysis shows a number of common characteristic frequencies in the data arrays. The annual cycle of all the variables is clearly evident. A common time period of two to three years is also found, as well as a higher frequency variability corresponding to five to six months

Multivariate analysis of climate variables, teleconnection indices and activities of lead-210 and beryllium-7 in surface air in Belgrade, Serbia

Activities of lead-210 and beryllium-7 have been monitored at the Vinča Institute of Nuclear Sciences in Belgrade, Serbia. The monthly mean activities in composite aerosol samples were determined on HPGe detectors by standard gamma spectrometry. The meteorological data, consisting of the temperature, atmospheric pressure, relative humidity, sunshine hours and cloud cover data were obtained from the European Climate Assessment & Dataset and the Republic Hydrometeorological Service of Serbia. Five teleconnection indices of large scale atmospheric circulation: North Atlantic Oscillation, East Atlantic Pattern, East Atlantic/West Russia Pattern, Scandinavia Pattern, and Polar/Eurasia Pattern were obtained from the data archive of the United States National Oceanic and Atmospheric Administration's Climate Prediction Center. The first lead-210 and beryllium-7 activities measured at the Vinča Institute date back to 1985 and 1991, respectively, and their relation with the climate variables and teleconnection indices is investigated using multivariate methods of analysis. The most appropriate multivariate method of analysis of these sets of measurements is selected from a wide spectrum of multivariate methods developed for data analysis in high-energy physics and implemented in the Toolkit for Multivariate Analysis software package. The evaluation ranking results based on the best signal efficiency and purity, show that the Boosted Decision Trees (BDT) multivariate method is the most suitable for the variable analysis. Further multivariate analysis results give insight into the dependence of lead-210 and beryllium-7 concentrations upon the climate variables and atmospheric circulation (via the teleconnection indices) during the time of measurements. The BDT method singles out the Scandinavia Pattern index as the variable with the highest importance for both radionuclides. Amongst the climate variables, temperature shows the strongest influence on the radionuclide concentrations, while relative humidity is the lowest ranking variable. Moreover, the multivariate regression methods give a good approximation of lead-210 and beryllium-7 concentrations for all the sets of climate variables and teleconnection indices

EKSTREMNO VISOKE VREDNOSTI SPECIFIČNE AKTIVNOSTI BERILIJUMA-7 U PRIZEMNOM SLOJU ATMOSFERE U EVROPI

Seasonal and spatial patterns of extremely high beryllium-7 surface concentration recorded over the 2001–2010 period across Europe are investigated. The beryllium-7 measurements for 14 sites are taken from the Radioactivity Environmental Monitoring Database. The maxima and minima in the annual cycle of the beryllium-7 surface concentration occur later in the year as the latitude of the measurement site decreases. Extremely high beryllium-7 surface concentrations are defined here as values greater than the 95th percentile in each measurement site. Most of the extremes occur over the March–August period. At least 10 % of the total number of extremes appear during autumn and winter, with an exception of Vienna, where all the extremes took place during spring and summer. The regional spread of extremes common to pairs of measurement sites points to an existence of three distinct regions in Europe: north of 55 °N, between 45 °N and 55 °N, and south of 45 °N. Although the beryllium-7 concentration records are significantly correlated across all the investigated sites, the strongest correlations are found within the identified regions.Sezonska i prostorna raspodela ekstremno visokih specifičnih aktivnosti berilijuma-7 u prizemnom sloju atmosfere analizirane su u ovom radu. Merenja tokom 2001–2010. godine na 14 evropskih stanica preuzeta su iz REMdb–baze podataka Monitoring radioaktivnosti u životnoj sredini. Prvo su razmotreni godišnji ciklusi specifične aktivnosti berillijuma-7 koji pokazuju da se godišnje maksimalne i minimalne srednje mesečne vrednosti pomeraju ka kasnijim mesecima kako se smanjuje geografska širina merne stanice. Za ekstremno visoke vrednosti specifične aktivnosti berilijuma-7 uzete su vrednosti veće od 95-og percentila, koji je izračunat za svaku stanicu posebno. Najveći broj ovih ekstrema događa se od marta do avgusta, a najmanje 10 % od ukupnog broja ekstrema tokom jeseni i zime. Izuzetak je merna stanica Beč na kojoj su se svi ekstremi dogodili tokom proleća i leta. Rasprostranjenost ekstrema koji su zajednički za parove mernih mesta, ukazuje da postoje tri različita regiona u Evropi: severno od 55 °N, između 45 °N i 55 °N, i južno od 45 °N. Iako su merenja specifične aktivnosti berilijuma-7 značajno korelisana za sve analizirane stanice, najveći koeficijenti korelacije dobijeni su u okviru ovih regiona

Elemental composition of moss and lichen species in eastern Serbia

Instrumental neutron activation analysis is used to determine a content of 47 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Ag, Cd, Sb, I, Ba, Cs, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Tm, Yb, Lu, Hf, Ta, W, Au, Hg, Th, and U) in mosses (Homolothecium sp., Hypnum cupressiforme Hedw., and Brachythecium mildeanum (Schimp.) Schimp.) and lichen (Cladonia fimbriata (L.) Fr.) collected in three locations in Eastern Serbia over years 2006-2010. Concentrations of six elements (Zr, Nd, Gd, Tm, Yb, and Lu) in mosses in Serbia are measured for the first time. For other elements, the obtained concentrations fall within the ranges reported for mosses and lichens in Europe, but no declining trend in concentrations of V, Cd, Cr, Zn, Ni, Fe, and Cu, that has been described in the literature, can be inferred from our results. Factor analysis shows that terrigenous and industrial components are the highest contributing factors to the elemental composition and that the most polluted measurement site is in the vicinity of a copper mining and smelting complex. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III43007: Climate changes and their influence on the environment: impacts, adaptation and mitigation and Grant no. III43009: New Technologies in the Environmental Protection

Characteristics of radioactivity in the surface air along the 45°N zonal belt in South-Eastern Europe

This study investigates the beryllium-7, lead-210 and caesium-137 activity concentrations in aerosol filter samples collected monthly along the 45°N zonal belt over 1991–2019. Sampling was performed in three locations, one in Serbia and two in Slovenia, and the Slovenian data records are published here for the first time. The activity concentrations were determined by standard gamma spectrometry. The obtained results are in general agreement with the literature data for Europe. The data sets at different sites display similarities in measurement ranges, overall means and seasonal cycles. Still, statistical tests show significant differences among the radionuclides’ concentrations across the locations. To investigate underlying processes that affect radioactivity in the surface air in this region, multivariate statistical concepts are applied to the radionuclides’ concentrations and local meteorological parameters. Discriminant analysis shows that all three sites are well separated from each other. Principal component analysis gives common pattern of interconnection between the observables: temperature has a stronger influence on the behaviour of beryllium-7 and lead-210 than that of caesium-137, but a negative correlation of the radionuclides’ concentrations with precipitation seems the strongest for caesium-137. Principal component analysis also shows local differences in the degree of relationship between the meteorological parameters and activity concentrations of the investigated radionuclides. This is an important finding for future atmospheric transport studies

Characteristics of radioactivity in the surface air along the 45°N zonal belt in South-Eastern Europe

This study investigates the beryllium-7, lead-210 and caesium-137 activity concentrations in aerosol filter samples collected monthly along the 45°N zonal belt over 1991–2019. Sampling was performed in three locations, one in Serbia and two in Slovenia, and the Slovenian data records are published here for the first time. The activity concentrations were determined by standard gamma spectrometry. The obtained results are in general agreement with the literature data for Europe. The data sets at different sites display similarities in measurement ranges, overall means and seasonal cycles. Still, statistical tests show significant differences among the radionuclides’ concentrations across the locations. To investigate underlying processes that affect radioactivity in the surface air in this region, multivariate statistical concepts are applied to the radionuclides’ concentrations and local meteorological parameters. Discriminant analysis shows that all three sites are well separated from each other. Principal component analysis gives common pattern of interconnection between the observables: temperature has a stronger influence on the behaviour of beryllium-7 and lead-210 than that of caesium-137, but a negative correlation of the radionuclides’ concentrations with precipitation seems the strongest for caesium-137. Principal component analysis also shows local differences in the degree of relationship between the meteorological parameters and activity concentrations of the investigated radionuclides. This is an important finding for future atmospheric transport studies