Evaluation of Representativeness of Samples Used for Indoor Radon Surveys (original) (raw)
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Radiation Measurements, 2013
Representative national surveys in dwellings are important to unbiasedly evaluate the exposure of the general population to radon. In Italy, a representative national survey was conducted from 1989 to 1996, which involved about 5600 dwellings in 232 towns. Later on, some Regions carried out more detailed surveys, but a new national survey in dwellings is necessary in order to obtain a more thorough estimate of radon concentration distribution over the Italian territory. The need to make this survey in an affordable way led to implement a new approach based on the collaboration between the Istituto Superiore di Sanità and a national company with workplaces and employees' homes throughout the country. The intent is to carry out a proxy of a population representative survey by measuring radon concentration in the homes of a random sample of the company employees. The realisation of this survey was affordable, thanks to the availability of corporate e-mail for each employee, intranet service, and company internal mail service. A dedicated web procedure and e-questionnaires allowed to automatically manage the contact with employees and to collect their data, which were both cost-and timesaving. Using this e-mail contact approach, 53% of contacted employees consented to participate in the survey. Radon concentration passive measuring devices were distributed to about 7000 dwellings, using about 14000 CR-39 detectors (two measured rooms per dwelling). In order to reduce costs, the devices were exposed for 12 months instead of two consecutive 6-month periods (as with the former national survey). A first checking of the actual representativeness of the sample was done by comparing characteristics of dwellings and occupants in the sample with corresponding data from the latest National Census. This was accomplished thanks to the fact that the questions in the survey questionnaire were tailored to the categories adopted for the Census questionnaire. A preliminary comparison showed that, at national level, the Italian dwellings are quite well represented by the sample.
Radon Indoor in Lombardy : A Geostatistical Approach for Identifying Prone Areas
2008
Radon is a natural radioactive gas known to be the main contributor to natural background radiation exposure and the major leading cause of lung cancer second to smoking. Indoor radon concentration levels of 200 and 400 Bq /m are reference values suggested by the 90/143/Euratom recommendation, above which mitigati on measures should be taken in new and old buildings, respectively, to reduce exposure to rado n. Despite this international recommendation, Italy still does not have mandatory regulations or guidelines to deal with radon in dwellings. Monitoring surveys have been undertaken in a number of western European countries in order to assess the exposure of people to this radioactive g as and to identify radon prone areas. However, such campaigns provide concentration values in each single dwelling included in the sample, while it is often necessary to provide measures of the po llutant concentration which refer to sub-areas of the region under study. In this paper, we propose a ...
Results of the Representative Italian National Survey on Radon Indoors
Health Physics, 1996
A representative national survey on population exposure to radon in Italian dwellings was carried out from 1989 to 1994, with the co-operation of the National Health Service. The measurements were performed by 19 Regional Laboratories, all using the same techniques and protocols. A stratified, two-stage sampling procedure was used to sample families. The sampled families were approached door-to-door to maximize response. To optimize the quality of the measurements, two dosimeters, each containing two alpha track detectors, were placed together in one room (typically the bedroom) for two consecutive 6-mo periods. The distribution of annual radon concentration was derived from measurements in 4,866 dwellings. The average value is 75 Bq m-' and the fractions of dwellings above the reference levels of 150,200,400, and 600 Bq m-' are 8.7%, 4.7%, 1.09' 0, and 0.2%, respectively. The geometric mean is 57 Bq m-3 while the geometric standard deviation is 2.0. The average values in the Italian Regions fall within the 20-120 Bq m-3 range. When the average radon concentration is examined vs. story, building materials seem to play a significant role. The average lifetime risk of lung cancer for chronic radon exposure of Italian population at home would be about 5 X using the risk factor proposed by the ICRP in 1993.
Reliable, comparable and 'fit for purpose' results are essential requirements for any decision based on analytical measurements. For the analyst, the availability of tested and validated sampling and analytical procedures is an extremely important tool for carrying out such measurements. For maximum utility, such procedures should be comprehensive, clearly formulated and readily available to both the analyst and the customer for reference. In the specific case of radon surveys, it is very important to design a survey in such a way as to obtain results that can reasonably be considered representative of a population. Since 2004, the Environment Programme of the IAEA has included activities aimed at the development of a set of procedures for the measurement of radionuclides in terrestrial environmental samples. The development of radon measurement procedures for national and regional surveys started with the collection and review of more than 160 relevant scientific papers. On...
The indoor radon survey in Serbian schools: can it reflect also the general population exposure?
A systematic indoor radon survey in elementary schools of Serbia is underway since 2008. Its current first phase covers all elementary schools in predominantly rural communities of Southern Serbia. The design of the survey, its implementation and the current state of its realization is shortly described. Part of this paper is devoted to discussion of the question if this survey could produce results representative also of the radon concentration in dwellings and of radon exposure of the general population, discussing some statistical aspects of representativity which arose during the work, namely, if the implementation leads to an unbiased estimate of the targeted quantities.
Environmental and Ecological Statistics, 2011
Indoor radon is an important risk factor for human health. Indeed radon inhalation is considered the second cause of lung cancer after smoking. During the last decades, in many countries huge efforts have been made in order to measuring, mapping and predicting radon levels in dwellings. Various researches have been devoted to identify those areas within the country where high radon concentrations are more likely to be found. Data collected through indoor radon surveys have been analysed adopting various statistical approaches, among which hierarchical Bayesian models and geostatistical tools are worth noting. The essential goal of this paper regards the identification of high radon concentration areas (the so-called radon prone areas) in the Abruzzo Region (Italy). In order to accurately pinpoint zones deserving attention for mitigation purpose, we adopt spatial cluster detection techniques, traditionally employed in epidemiology. As a first step, we assume that indoor radon measurements do not arise from a continuous spatial process; thus the geographic locations of dwellings where the radon measurements have been taken can be viewed as a realization of a spatial point process. Following this perspective, we adopt and compare recent cluster detection techniques: the simulated annealing scan statistic, the case event approach based on distance regression on the selection order and the elliptic spatial scan statistic. The analysis includes data collected during surveys carried
Journal of the European Radon Association, 2022
Background: As a major cause of lung cancer after smoking, indoor radon is a hazard for human health. Key steps of radon surveys are numerous and include metrology, survey design, development of maps, communication of results to stakeholders, etc. The Council Directive 2013/59/EURATOM introduced new challenges for European Union Member States, such as the identification of radon priority areas, which calls for efforts to improve all the key steps involved in radon surveys. Objective: This study aims to compare existing radon measurement procedures between different European countries and to use the results to optimize the consistency of indoor radon data across Europe. Design: A questionnaire was developed and sent to more than 70 European institutions working in this field to collect information on indoor radon surveys carried out in the respective countries, in order to identify the rationale and methodologies used. Results: A total of 56 questionnaire forms on indoor radon survey...
Journal of Physics: Conference Series
Since some years ago in Abruzzo (Central Italy), through a number of monitoring campaigns, a set of more than 1900 indoor radon measures has been acquired by the Regional Agency for the environmental protection. Thus, on the basis of these public experimental data, different statistical approaches, aimed to estimate the probability to exceed the level of 200 Bq/m 3 (lower than 300 Bq/m 3 , threshold value currently recommended by the Euratom commission for indoor radon risk acceptability), taken just as a working reference value, have been selected and discussed in this paper. Essentially, 'Monte Carlo Empirical Bayesian approach', 'Bootstrap' and 'Gibbs samplers' methods have been applied and the results have been partially compared. Moreover, some insights on the minimum number of samples, needed to assess the probability distribution as reasonable as possible, are provided.
Radiation Measurements, 2005
A representative National Survey to evaluate the exposure to natural sources of ionizing radiation in dwellings was conducted in all the 21 Italian Regions from 1989 to 1998, and the complete results are reported in this paper. Radon concentration was measured for two consecutive 6-month periods (generally covering the spring-summer and autumn-winter seasons) in one room, usually the main bedroom, of each surveyed dwelling. Validated radon concentration measurements were obtained for F. Bochicchio et al. / Radiation Measurements 40 (2005) 686 -694 687 a total of 5631 dwellings, distributed in 232 towns (all the 50 towns with more than 100,000 inhabitants and 182 randomly sampled smaller towns). The national average, weighted by the population of each Region, of the annual radon concentration is 70 Bq m −3 , the geometric mean is 52 Bq m −3 , and the geometric standard deviation is 2.1. The fraction of dwellings with a radon concentration exceeding the reference levels of 150, 200, 400, and 600 Bq m −3 are 7.7%, 4.1%, 0.9%, and 0.2%, respectively. Regional averages ranged from about 25 Bq m −3 to about 120 Bq m −3 . The uncertainty of regional values can be relevant in the case of small Regions, where few small towns were sampled, however such uncertainties do not affect national values significantly. A log-normal model underestimates the fraction of dwellings with high radon concentration and needs to be adjusted to obtain a better fitting. Two complete 6-month measurements were obtained for 4742 dwellings. The regional values of the geometric mean and of the geometric standard deviation of the winter/summer ratio ranged from 0.81 to 2.58 and from 1.32 to 1.88, respectively. The corresponding national values were 1.23 and 1.71, respectively. These results and their implications are discussed in the paper.
Journal of Environmental Radioactivity, 2013
Radon-222 is a radioactive natural gas produced by the decay of radium-226, known to be the main contributor to natural background radiation exposure. Effective risk management needs to determine the areas in which the density of buildings with high radon levels is likely to be highest. Predicting radon exposure from the location and characteristics of a dwelling could also contribute to epidemiological studies. Beginning in the nineteen-eighties, a national radon survey consisting in more than 10,000 measurements of indoor radon concentrations was conducted in French dwellings by the Institute for Radiological Protection and Nuclear Safety (IRSN). Housing characteristics, which may influence radon accumulation in dwellings, were also collected. More recently, the IRSN generated a French geogenic radon potential map based on the interpretation of geological features. The present study analyzed the two datasets to investigate the factors influencing indoor radon concentrations using statistical modeling and to determine the optimum use of the information on geogenic radon potential that showed the best statistical association with indoor radon concentration. The results showed that the variables associated with indoor radon concentrations were geogenic radon potential, building material, year of construction, foundation type, building type and floor level. The model, which included the surrounding geogenic radon potential (i.e. the average geogenic radon potential within a disc of radius 20 km centered on the indoor radon measurement point) and variables describing house-specific factors and lifestyle explained about 20% of the overall variability of the logarithm of radon concentration. The surrounding geogenic radon potential was fairly closely associated with the local average indoor radon concentration. The prevalence of exposure to radon above specific thresholds and the average exposures to radon clearly increased with increasing classes of geogenic radon potential. Combining the two datasets enabled improved assessment of radon exposure in a given area in France.