Indoor Radon Concentrations In Dwellings Research Articles

Study of radium content and radon exhalation rates in raw building materials used in southern India

As a potential source of indoor radiation arising from radon, a range of building materials (white cement, gray cement, gravel, gypsum, granite, marble, vitrified tile, and brick) were studied for the specific activity of radium and radon gas exhalation rates. The activity of radium was determined using scintillation gamma-ray spectrometry. Exhalation rates were assessed using passive and active measurement methods. Radon mass exhalation rates from powdered building materials and radon surface exhalation rates from slab-type building materials were measured. Activity concentrations of 226Ra in powder and slab-type building materials were found in the range of (1.12 – 14.98) Bqkg−1 and (17 – 308) Bqkg−1, respectively. 222Rn mass exhalation rates (mBqkg−1h−1) from the building materials were in the range of 15.0 ± 0.8 (gray cement) to 1.1 ± 0.1 (gravel). Surface exhalation rates (mBqm−2h−1) for slab-type materials have a range of 317 ± 9 (brick) to 8 ± 2 (marble). Strong positive correlations were found between the specific activity of radium and radon mass exhalation rates (r = 0.9408) and radon surface exhalation rates (r = 0.7167) for building materials investigated. Obtained data indicates that the building materials used influence indoor radon concentration in dwellings.

A survey of 222Rn concentrations in dwellings of the town of Metsovo in North-western Greece

A radon survey has been carried out of indoor radon concentrations in dwellings ocated in the town of Metsovo, in north-western Greece. To measure indoor radon ioncentrations, CR-39 detectors were installed in randomly selected houses and were exposed :or about 3 months, during summer and winter. Also gamma spectroscopy measurements of he soil's radium content were performed. The indoor radon concentration levels varied from [7.6 to 750.4 Bq m-3, while the radium concentration of soil varied from 4.9 to 97.1 Bq m"3. Seasonal variation of the radon levels and the influence of house features and sou are liscussed.

Local probability of indoor radon concentration to exceed the threshold estimated from geogenic radon potential

Indoor radon has been recognized as an important air pollutant. Based on epidemiological evidence, it is estimated that indoor radon is the second cause of lung cancer after smoking. As a consequence, one tries to limit exposure through regulations concerning the remediation of the existing and prevention of future exposure. In this context, an essential task is the delineation of areas in which it can be expected with certain confidence that time-averaged indoor radon concentrations in dwellings and workplaces exceed the reference level. These are called radon priority areas to denote that these are areas in which remedial and preventive action has to be implemented with priority. There are different definitions of radon priority areas and different methods to estimate them from data. In Germany, the current approach uses the geogenic radon potential as the predictor. However, legal reference levels pertain to indoor radon concentration, not to the geogenic radon potential. One therefore has to identify derived reference levels for geogenic radon potential through statistical association of both quantities. This paper presents a method to derive the local probability that indoor radon concentration exceeds a threshold, given the local geogenic radon potential. The relationship can be used to derive geogenic radon potential reference levels which in turn serve to define radon priority areas.

Indoor radon risk associated to post-tectonic biotite granites from Vila Pouca de Aguiar pluton, northern Portugal

At Vila Pouca de Aguiar area, northern Portugal, crops out a post-tectonic Variscan granite pluton, related with the Régua-Vila Real-Verín fault zone, comprising three types of biotite granites. Among these granites, PSG granite yield the highest average contents of U, probably due to its enrichment in accessory U-bearing minerals such as zircon. In the proximity of faults and joints, these granites are often affected by different degrees of hydrothermal alteration, forming reddish altered rocks, commonly known as “episyenites”. These altered rocks are probably associated to the occurrence of hydrothermal processes, which led to uranium enrichment in the most advanced stages of episyenitization. In these granites, both average gamma absorbed dose rates in outdoor and indoor air are higher than those of the world average. Furthermore, even in the worst usage scenario, all these granites can be used as a building material, since their annual effective doses are similar to the limit defined by the European Commission. The geometric mean of radon activity of 91 dwellings located at the Vila Pouca de Aguiar pluton is 568Bqm−3, exceeding that of other northern Portuguese granites. Measurements carried out during a winter season, indicate that 62.6% of the analysed dwellings yield higher indoor radon average values than the Portuguese legislation limit (400Bqm−3), and annual effective doses due higher than the world’s average value (1.2mSvy−1).The interaction of geogenic, architectural and anthropogenic features is crucial to explain the variance in the geometric mean of radon activity of dwellings from Vila Pouca de Aguiar pluton, but the role of geologic faults is probably the most important decisive factor to increase the indoor radon concentration in dwellings. Hence, the development of awareness campaigns in order to inform population about the incurred radiological risks to radon exposure are highly recommended for this specific area.

Estimation of the residential radon levels and the annual effective dose in dwellings of Shiraz, Iran, in 2015.

IntroductionRadon is the second most important cause of lung cancer after smoking. Thus, the determination of indoor radon concentrations in dwellings and workplaces is an important public health concern. The purpose of this research was to measure the concentration of radon gas in residential homes and public places in the city of Shiraz and its relationship with the type and age of the buildings as well as the type of materials used to construct the building (brick, block). We also determined the radon dosages that occupants of the building would receive.MethodsThe present study is a descriptive-analytical and cross-sectional research that was conducted on the building’s indoor air in the city of Shiraz in 2015. Using geographic information system (GIS) software and a spatial sampling cell with an area of 25 square kilometers, 200 points were selected. In this study, we used passive diffusive samplers as Solid State Nuclear Track Detector (SSNTD) CR-39 polycarbonate films for three months in the winter. Sampling was conducted in accordance with the U.S. Environmental Protection Agency’s protocol. We determined the concentrations of radon gas at the time of sampling, and calibration factors were determined. The data were analyzed by IBM-SPSS, version 20, descriptive statistics, Kruskal-Wallis, and Mann–Whitney tests.ResultsThis study showed that the average radon concentration was 57.6 ± 33.06 Bq/m3 in residential dwellings. The average effective dose was 1.45 mSv/y. The concentration of radon in 5.4% of the houses was found to be greater than 100 Bq/m3, which is above the level allowed by the World Health Organization (WHO).ConclusionSince radon is the second leading cause of lung cancer, it seems necessary to increase the public’s awareness of this issue and to take action to reduce radon in homes when the concentrations are above the WHO’s guideline.

Assessment of Indoor Radon Concentrations in Dwellings for Baghdad Governorate by Using RAD-7 Detector

In the present work, radon gas concentrations in different dwellings in Baghdad governorate are measured by using RAD-7 detector. The results have shown that, the radon gas concentrations ranged between (40.67 ± 3.1 Bq/m3) to (190.00 ± 2.7 Bq/m3) with an average value (113.66 ± 30.2 Bq/m3); in the first one we draw the map radiations for indoor radon gas concentrations in Baghdad governorate. We would like to mention that the present study is considered to be very important and vital because it is concerned with people health and safety in the first place.

FIRST STEP TOWARDS THE GEOGRAPHICAL DISTRIBUTION OF INDOOR RADON IN DWELLINGS IN ALBANIA.

The realisation of the geographical distribution of the indoor radon concentrations in dwellings represents a valuable tool necessary for assessing the public exposure. In this work are reported the results of the indoor radon obtained in the first stage of the survey involving 247 measurements. From the preliminary information on ∼10 % of the territory, covering the biggest cities in Albania results on indoor radon concentrations ranging from 14 to 1238 Bq m-3 with an arithmetic mean of 120±67 Bq m-3 The population-weighted average indoor radon concentration was calculated to be 101 Bq m-3 The adopted survey strategy highlighted the necessity for the future stages to spread the measurements in order to cover the entire territory of Albania, instead of remaining focused only on the demographic criteria.

An Investigation of Factors Influencing Indoor Radon Concentrations in Dwellings of Northern Rajasthan, India

Abstract An effort has been made to find possible relationships of indoor radon levels with building construction materials, ventilation condition of dwellings and soil gas radon levels. Indoor radon measurements were made using LR-115 type II cellulose nitrate films and the concentrations were estimated by knowing the track density of films through optical microscope. Soil gas radon levels were measured using RAD7, an electronic radon detector manufactured by Durridge Company, USA. This study sheds light on the seasonal indoor radon activities in Rajasthan dwellings. Maximum values of the indoor radon concentration were observed during the winter and minimum during the summer season. Results show that ventilation rate is inversely proportional to radon level. Highest level of indoor radon concentration was found in the mud type dwellings compared with dwellings made of concrete, cement and marble. A positive correlation (R2 = 0.45) between indoor radon and soil gas radon concentration was observed. A weak positive correlation (R2 = 0.22) was observed between soil gas radon concentration and radium content in soil. Indoor radon concentration was found to be associated with the presence of radon concentration in local soil, building material used for roof, floor and walls, type of ventilation conditions and presence of cracks on the walls/floor. Positive correlation between indoor and soil gas radon concentration suggest the large contribution of local soil towards indoor radon.

Indoor Radon Concentrations in Dwellings of Ischia Island

Indoor radon concentration measurements were performed in dwellings of Ischia island (South Italy) using commercial E-Perm devices in LST configuration. The average concentrations in the dwellings were found to vary from 125 to 865 Bq/m3 with an average of 354 ± 176 Bq/m3. This value is higher than Italian National average that is 75 Bq/m3 and Campanian average that is 95 Bq/m3. Correlation between indoor radon concentration measurements and floor level of monitored room was also studied.

Life time fatality risk assessment due to variation of indoor radon concentration in dwellings in western Haryana, India

Indoor radon measurements in 60 dwellings belonging to 12 villages of Sirsa, Fatehbad and Hisar districts of western Haryana, India, have been carried out, using LR-115 type II cellulose nitrate films in the bare mode. The annual average indoor radon value in the studied area varies from 76.00 to 115.46Bqm−3, which is well within the recommended action level 200–300Bqm−3 (ICRP, 2009). The winter/summer ratio of indoor radon ranges from 0.78 to 2.99 with an average of 1.52. The values of annual average dose received by the residents and Life time fatality risk assessment due to variation of indoor radon concentration in dwellings of studied area suggests that there is no significance threat to the human beings due to the presence of natural radon in the dwellings.

Assessment of seasonal indoor radon concentration in dwellings of Western Haryana

Abstract Naturally occurring radon 222Rn in indoor air is a significant cause of lung cancer and the houses are an important exposure location due to the large proportion of time spent at home. The indoor radon measurements have been carried out in some of the dwellings belonging to different villages of Fatehbad and Hisar districts of Western Haryana. LR-115 Type II plastic track detectors in bare mode were used for the measurement of indoor radon concentration for over a period of one year. The calculated annual average indoor radon concentration values vary from 126.3 Bq m−3 to 172.1 Bq m−3 with an average value of 145.21 Bq m−3, which is less than the recommended action level (200–300 Bq m−3). The values of annual effective dose vary from 2.16 mSv to 2.94 mSv which is less than the lower limit of the recommended action level (3–10 mSv). The measured values of lifetime fatality risk vary from 1.67 to 2.27 with an average value of 1.92. The winter to summer ratio calculated for the studied dwellings ranges from 0.86 to 2.15 with an average of 1.46. The results indicate that the indoor radon concentration is higher in winter season than in the summer season. An attempt has also been made to find a correlation between the ventilation conditions and the measured values of indoor radon concentration. In most of the cases the radon values are less in well ventilated houses than partially/poorly ventilated houses. The measured indoor radon concentration values for the studied area are on the higher side than the world average of 40 Bq m−3.

Geochemistry of granites and metasediments of the urban area of Vila Real (northern Portugal) and correlative radon risk

Radon concentration was evaluated in dwellings of the urban area of Vila Real (Northern Portugal). The area is mainly composed of Hercynian granites and Cambrian metasediments, and CR-39 passive detectors (n = 112) were used for the purpose. The results obtained in winter conditions suggest that the most productive geological unit is the Hercynian granite G1 (geometric mean of 364 Bq/m3), while Cambrian metasediments of the Douro Group show the lowest average indoor radon concentration (236 Bq/m3). The geological, geochemical and radiological data obtained suggest that the most effective control on the radon concentrations of the area is related with the uranium content of the rocks; indeed, the highest contents were observed in granite G1 (21 ppm) and the lowest in the metasediments (3 ppm). This is also confirmed by the results obtained for groundwater, where granites present the highest concentrations of dissolved radon (up to 938 Bq/l), uranium (5–18 ppb) and gross α activities (0.47–0.92 Bq/l). No important radiometric anomalies were found in relation with geological structures such as faults, veins and contacts, but a moderate increase of the uranium content can occur locally in such structures. Petrographic observations and SEM studies show that uranium is mainly contained within the rock in heavy accessory minerals (apatite, zircon, monazite, xenotime), which reduces radon emanation. Notwithstanding, due to the high U contents granites show a significant potential to induce indoor radon concentrations in dwellings in excess of the recommended value of 400 Bq/m3. Overall, we can conclude that the region of Vila Real presents a moderate to high radon risk in dwellings and groundwater.

Seasonal variation of indoor radon concentration in dwellings of Alexandria city, Egypt

Inhalation of radon ((222)Rn) and daughter products are a major source of natural radiation exposure. Keeping this in view, seasonal indoor radon measurement studies have been carried out in 68 dwellings belonging to 17 residential areas in Alexandria city, Egypt. LR-115 Type 2 films were exposed for four seasons of 3 months each covering a period of 1 y for the measurement of indoor radon levels. Assuming an indoor occupancy factor of 0.8 and a factor of 0.4 for the equilibrium factor of radon indoors, it was found that the estimated annual average indoor radon concentration in the houses surveyed ranged from 45 ± 8 to 90 ± 13 Bq m(-3) with an overall average value of 65 ± 10 Bq m(-3). The observed annual average values are greater than the world average of 40 Bq m(-3). Seasonal variation of indoor radon shows that maximum radon concentrations were observed in the winter season, whereas minimum levels were observed in the summer season. The season/annual ratios for different type of dwellings varied from 1.54 to 2.50. The mean annual estimated effective dose received by the residents of the studied area was estimated to be 1.10 mSv. The annual estimated effective dose is less than the recommended action level (3-10 mSv y(-1)).

Indoor radon concentration measurement in the dwellings of district Poonch (Azad Kashmir), Pakistan

The present study deals with measurement of indoor radon concentrations in dwellings of the district Poonch of the state of Azad Jammu and Kashmir, Pakistan. In this context, CR-39-based box-type radon detectors were installed in drawing rooms and bedrooms of 80 selected houses and were exposed to indoor radon for 3 months. After exposure, the CR-39 detectors were etched for 9 h in 6 mol NaOH at 70 degrees C and the observed track densities were related to radon concentrations. Measured indoor radon concentrations in the studied area ranged from 27 +/- 6 to 169 +/- 4, 29 +/- 6 to 196 +/- 4 and 31 +/- 5 to 142 +/- 2 Bq m(-3) in the drawing rooms and 74 +/- 5 to 172 +/- 3, 32 +/- 6 to 191 +/- 4 and 27 +/- 5 to 155 +/- 2 Bq m(-3) in bedrooms of the Abbaspur, Hajira and Rawalakot regions of the district Poonch, respectively; whereas weighted average radon concentration ranged from 93 +/- 6 to 159 +/- 4, 33 +/- 5 to 118 +/- 3 and 31 +/- 6 to 155 +/- 5 Bq m(-3) in the dwellings of Abbaspur, Hajira and Rawalakot, respectively. Estimated doses due to the indoor radon ranged from 2.35 +/- 0.15 to 4.00 +/- 0.10, 0.83 +/- 0.08 to 2.98 +/- 0.08 and 0.78 +/- 0.15 to 3.91 +/- 0.13 mSv y(-1) for Abbaspur, Rawalakot and Hajira, respectively. Comparing the current indoor radon results with those of the Health Protection Agency UK and US EPA (i.e. 200 and 148 Bq m(-3)) limits, majority of the houses surveyed in the present study are within the safe limits.

Seasonal variation in indoor radon concentrations in dwellings in six districts of the Punjabprovince, Pakistan

An indoor radon measurement survey has been carried out in six districts ofthe Punjab province. These included Gujranwala, Gujrat, Hafizabad, Sialkot,Narowal and Mandibahauddin districts. In each district, 40 representative houseswere chosen and indoor radon levels were measured in these dwellings in autumn,winter, spring and summer seasons using CR-39 based NRPB radon dosimeters.After exposure to radon, the CR-39 detectors were etched in 25% NaOH at80 °C and track densities were related to radon concentration levels. From the observed data, averageradon concentration levels and a seasonal correction factor were calculated. The average222Rn concentration levelwas found to vary from 40 ± 15 to 160 ± 32 Bq m−3 and 38 ± 17 to 141 ± 26 Bq m−3 in the bedrooms and living rooms of the houses surveyed, respectively. The annual meaneffective dose received by the occupants has been calculated using ICRP (1993 Ann.ICRP 23) and UNSCEAR (2000 Sources and Effects of Ionizing Radiation (NewYork: United Nations)); it varied from 1.2 to 1.7 mSv and from 1.8 to 2.4 mSv,respectively.

Indoor radon concentration in the rural dwellings of Chhattisgarh state (India)

Inhalation of radon and its daughter products is the major contributor to the total exposure of the population to natural radiation. An indoor radon survey has been carried out in the state of Chhattisgarh (80.26 degrees N to 84.41 degrees N and 17.8 degrees E to 24.1 degrees E), India under the national coordinated radon project of the Department of Atomic Energy. In the frame of this project indoor radon concentration has been measured in 105 dwellings situated in different villages of Chhattisgarh state. Houses were selected for measurements to cover the most common type of houses generally existing in the rural areas. Measurements have been done on quarterly integrating cycle for one full year in each dwelling using radon cup dosemeter employing LR-115, type-II (pelliculable), solid-state nuclear track detectors. The gamma radiation level was also checked in each dwelling using a gamma survey meter. It was found that the annual average indoor radon concentration in these dwellings varies from 9.91 to 87.84 Bq m(-3) with overall mean value of 26.48 Bq m(-3). Gamma level in these rural dwellings varies from 14.84 to 26.56 microR h(-1) with mean value of 18.68 microR h(-1). We observed that the radon concentration is relatively higher in the houses where the floor is bare but relatively lower in those houses where the floor is tiled or cemented.

INDOOR RADON DETERMINATION IN DWELLINGS LOCATED AT DIKILI GEOTHERMAL AREA IN WESTERN TURKEY

This paper presents the indoor radon concentrations in dwellings located in the Dikili geothermal area in western Turkey. Indoor radon monitoring was performed for 3 mo using 121 detectors installed in the living rooms and bedrooms of 62 houses selected from the region. A passive time-integrating radon measuring technique was applied by using CR-39 solid-state nuclear track detectors. Average indoor radon levels for the houses varied from 31 to 280 Bq m(-3). Corresponding annual effective doses were calculated, and risks for lung cancer due to inhalation of indoor radon were estimated.

Comparative studies of health hazard from radon (Rn-222) in two selected lithologic formations in the Suwałki region (in Poland)

The aim of this work was to make a comparison of indoor radon concentrations in dwellings and in soil air in the area of two geological formations in the Suwałki region (Poland). The mean arithmetic airborne concentration was found to be the highest (301 Bq m −3) in the basements of buildings in the gravel and sand areas, whereas in the boulder clay areas it reached 587 Bq m −3. Out of 54 measurements of radon concentrations performed at the ground floor, in eight cases concentrations were found to exceed 200 Bq m −3—permissible radon level in new-built houses in Poland and in three cases these values were even higher than 400 Bq m −3. The highest radon levels were noted in houses with earthen basement floors and with direct entrance from the basement to rooms or kitchens. The mean arithmetic radon concentration in the soil air in the sandy and gravel formations was 39.7 kBq m −3 and in clay formation it was 26.5 kBq m −3. Higher radon levels were also found in the water obtained from household wells reaching 8367 Bq m −3 as compared with tap water (2690 Bq m −3). The mean indoor concentration for the whole area under study was found to be 169.4 Bq m −3, which is higher than the mean value for Poland (49.1 Bq m −3) by a factor of 3.5.

A survey of 222Rn concentrations in dwellings of the town of Metsovo in north-western Greece.

A radon survey has been carried out of indoor radon concentrations in dwellings located in the town of Metsovo, in north-western Greece. To measure indoor radon concentrations, CR-39 detectors were installed in randomly selected houses and were exposed for about 3 mo, during summer and winter. Gamma spectroscopy measurements of the soil's radium content also were performed. The indoor radon concentration levels varied from 17.6 to 750.4 Bq m(-3), while the radium concentration of soil varied from 4.9 to 97.1 Bq m(-3). Seasonal variation of the radon levels and the influence of house features and soil are discussed.

Mitigation Methods in High Radon Areas in Germany

A high radon content in soil is the main cause for high indoor radon concentrations in dwellings. The areas around Ellweiler/Hunsruck, Neuenburg/Oberpflaz and Schneeberg/Erzgebirge are known for their high uranium and radium concentrations in soil. An additional region is classified as a 'high radon area' although there are no known uranium anomalies. This region is situated in the Eifel near the Nurburgring in a terrain of volcanic origin. In the Eifel indoor radon values up to 1500 Bq.m-3 have been detected. The indoor values in Ellweiler and around Neuenburg range from several hundreds up to 8000 Bq.m-3, whereas in Schneeberg, radon concentrations up to 300,000 Bq.m-3 in cellars and 100,000 Bq.m-3 in living rooms have been found in some houses. A general mitigation method of equal efficiency for all high radon-exposed houses does not exist. The radon concentration in a recently built house has been reduced successfully to a tenth by a complete insulation of the walls and the floor of the cellar rooms. By removing the subsoil air below the insulated concrete plate of the cellar, the radon concentration has been diminished to 20% and additional air ventilation has halved the radon values again.