Outdoor Radon Concentrations Research Articles

Radon Concentration in Air and Evaluation of the Radiation Dose in Villages near Shizhuyuan, Southern Hunan, China

Radon is one of the important natural sources of radiation and pollutants. When radon and its progeny are inhaled by the human body, they can cause radiation damage to the respiratory system and can lead to lung cancer. Indoor and outdoor radon concentrations were measured in five villages near Shizhuyuan W-polymetallic deposit using a RAD7 detector; moreover, the corresponding radiation dose and lifetime risk probability were evaluated. The results show that the average value of indoor radon concentration was 216.6±121.1 Bq m−3, which is above the worldwide average indoor radon level of 40 Bq m−3, and the average outdoor value was 34.6±13.4 Bq m−3, which is higher than the worldwide outdoor average of 10 Bq m−3. A total of 42% of the dwellings investigated in our study had a higher radon level than the Chinese permissible indoor radon level of 200 Bq m−3. The total annual effective dose ranged from 5.21 mSv y−1 to 49.38 mSv y−1, with an average value of 14.63 mSv y−1, which is higher than the ICRP recommended value of 3–10 mSv y−1. This average total dose value corresponds to an average lifetime risk probability of 5.8% for residents in the whole study area.

Study of variation of indoor radon levels in houses and prediction of indoor concentrations using house characteristics and outdoor radon levels.

The measurement of 222Rn concentrations in indoor and outdoor air was carried out in certain locations of Mandya city, Karnataka, using the Solid State Nuclear Track Detectors (SSNTD) technique. The annual mean values of 222Rn in indoor and outdoor are found to be 20.5±1.4 and 9.0±0.5Bqm-3, respectively. The observed mean value of indoor radon concentration is found to be well within the world and the Indian average of 40 and 42Bqm-3, respectively. Outdoor radon concentrations have been measured in the vicinity of houses where yearlong radon measurements carried out using the SSNTD technique. The seasonal variation in the outdoor radon was studied and the average concentrations during summer, rainy and winter are 9.1, 6.9 and 12.9Bqm-3 respectively. Considering the possible factors such as house characteristics (Volume, Surface area of building material, Leakage area, etc.), indoor-outdoor temperature difference and outdoor radon concentration into account, the indoor radon levels were predicted using the existing model which is based on the mass balance equation. The results are systematically analysed and discussed. The predicted values are compared with the measured values.

The use of radon as a tracer for air quality assessment: a case study in Bratislava, Slovakia

Air quality in urban areas is mainly controlled by emission sources and dispersion conditions. The mixing layer height (MLH) within which the pollutants are dispersed plays an important role in air pollution assessment. In this study, the MLH was determined based on the daily radon flux obtained from the European radon flux map and outdoor radon concentration measured in Bratislava, Slovakia. The radon-based MLH was compared with the boundary layer height obtained from the ERA-5 reanalysis dataset, showing good agreement. Using the Sturges grouping method and regression analysis, radon-based MLH showed significant correlations with the concentration of various atmospheric pollutants.

Method for assessing radon Re-Entrainment risks from above ground level discharges from sub-slab depressurization systems

Above ground level (ABL) discharges are commonly employed in northern climates to release radon-containing soil gases from sub-slab depressurization radon mitigation systems. While there are many practical reasons to employ this in cold climates (e.g., to avoid ice build-up), it does inherently elevate the outdoor radon concentrations, and raises the possibility of radon re-entrainment back into living spaces of the emitting house, and its neighbors. A method has been developed for assessing outdoor radon dispersion and re-entrainment risks. It links computational fluid dynamics calculations for evaluating outdoor concentrations, and regional multi-annual meteorological records that give the occurrence probability for different wind speed, wind direction, and atmospheric stability conditions. When combined with assumptions about indoor/outdoor concentration ratios, annual average exposure concentrations to radon can be estimated. Concentrations along surfaces of the emitting house are often quite high close to the exhaust vent, and air exchange into the house from nearby open windows, air intakes, etc., and can result in high indoor concentrations. Re-entrainment into the neighboring house is often less serious, though certain circumstances can lead to radon being trapped in the space between the two buildings, which leads to higher exposure.

Dispersion Simulations of Radon Discharges between Neighboring Buildings and Their Sensitivity to Meteorology, Discharge Rate, and Building Geometry.

In northern climates, it is common to install the discharges of radon sub-slab depressurization systems near ground level. However, this also elevates the ground level outdoor radon concentrations and raises the possibility of radon re-entrainment into homes. The study aims to assess outdoor radon concentrations near above-ground-level discharges along the surfaces of an emitting building and its close neighbor and identify parameters that most influence the dilution. This study employs a series of computational fluid dynamics calculations to assess concentrations along the exhaust-facing and non-exhaust-facing surfaces of the buildings. Different meteorological, venting, and building geometry parameters are explored. Boundary conditions for the CFD calculations are based on field measurements of the ground-level wind speeds and seasonal air temperatures and atmospheric stabilities. Outdoor concentrations can be as high as 7% of the discharge gas, although these become smaller at greater distances from the vent. The direction of the prevailing wind is a particularly important parameter, as it influences the formation of circulating building cavities and building wakes where radon could accumulate. The wind speed, atmospheric stability, and season (plume buoyancy) also have important influences on the outdoor radon concentrations, as do the velocity of the vent system and the size of the buildings. The study has assessed the dilution of the radon-laden exhaust gas and determined the outdoor concentrations that can be expected under a variety of conditions. These results can be used to inform regulators about the potential for radon re-entrainment into homes.

Radiological assessment subjected to outdoor radon and thoron concentrations and terrestrial gamma radiation measurements in Perak Malaysia

The concentrations of radon, thoron and terrestrial gamma radiation were measured to evaluate the outdoor effective dose. The outdoor radon activity concentration ranged from 5.79 to 5110 ± 46.36 Bq m−3, with a mean of 320.03 Bq m−3 which is higher than the EPA level of 14.8 Bq m−3. The range of the thoron activity concentration outdoor was from 0.00 to 4226.7 ± 58.5 Bq m−3, with a mean of 226.1 Bq m−3 which was above the UNSCEAR recommended level of 10 Bq m−3. The terrestrial gamma radiation dose rates range was from 98.31 to 3769.71 nGy h−1 with a mean of 446.27 nGy h−1. The effective dose contribution from radon exposures in the study was estimated to be 3.2 ± 0.5 mSv y−1 is about 84% total annual effective dose received by the population in those areas. The estimated thoron and gamma dose contributions (15%, and 1% respectively) were not significant. The outdoor doses for thoron and gamma were lower than the ICRP (2007) value of 1 mSv. The total annual outdoor effective dose with an occupancy factor of 1825 h (5 h day−1) was estimated to be within the range of 0.30–551.41 ± 0.65 mSv, with a mean of 3.75 mSv which is a little higher than the world average of 2.4 mSv.

Assessment of indoor and outdoor radon concentrations in Talysh, Azerbaijan

Assessment of indoor and outdoor radon concentrations in Talysh, Azerbaijan

A brief radiological survey and associated occupational exposure to radiation in an open pit slate mine in Kashan, Iran

A comprehensive radiological survey was carried out in an open-cut slate stone quarry. The activity of 226Ra, 228Ra and 40 K in the ore samples were measured as 38 ± 5, 41 ± 6 and 869 ± 52 Bq kg1, respectively. Outdoor radon and indoor radon concentrations were measured from 37 ± 7 to 193 ± 11 Bq m−3 (77 ± 8 Bq m−3), and 49 ± 6 to 253 ± 23 Bq m−3 (131 ± 13 Bq m−3), respectively. The average indoor and outdoor gamma dose were measured as 116 and 84 nSv h− 1, respectively. The annual effective doses were estimated between 1.0 ± 0.1 and 3.3 ± 0.3 mSv year−1. The annual lung cancer risks were calculated in the range of 3.3 × 10−2 to 13.12 × 10−2 % (7.72 × 10−2%).

Measurement of outdoor Radon Concentrations in Soil Samples collected from Karabuk University in Turkey by using CR-39 Detector

In this work, radon gas concentration in (35) samples of soil collected from Karabuk University in Turkey was measured by using nuclear track detector (CR-39). The content of radium, the rate of surface exhalation and the rate of mass exhalation have been assessed. The concentrations of radon were varied from (16.348 Bq.m−3) to (196.988 Bq.m−3). Results indicate that the equivalent content of radium varied from (0.386245 Bq.kg−1) to (4.654255 Bq.kg−1). The exhalation rate for surface varied from (0.002007 Bq.m−1.h−1) to (0.023031 Bq.m−1.h−1). The exhalation rate for mass varied from (0.000319 Bq.kg−1.h−1) to (0.00366 Bq.kg−1.h−1). All the obtained results found to be less than the corresponding limits for the world. Thus, based on the radon gas concentration and radiation, the equivalent content of radium (CRa), exhalation rate for the area (EArea) and exhalation rate for the mass (EMass) in this area have no risk to the human’s health.

CFD based simulation of indoor radon distribution from the use of different brands of decorative glazed tiles made in China

ABSTRACT The radon exhalation rates of the surface of 10 different brands of glazed tiles made in China are measured and assessed. The experimental results reveal that the values of radon exhalation rate from the surface of glazed tiles are in the range of 0.36–2.52 Bq·m2 h−1, with a mean of 1.48 Bq·m2 h−1. These measurements obtained in this study are much lower than the typical radon exhalation rate international reference value of soil, and are also within the range of the reported literatures. Meanwhile, these data are taken as input parameters of computational fluid dynamics (CFD) model for simulation comparative study. The different plane distribution of radon from the use of different brands of glazed tiles in the model residential room is simulated. The simulation results show that the distribution of radon concentration in different XY plane is un-even, and the values of radon concentrations in XY plane is decreasing with the increase of z height. Deducting the contribution of the worldwide typical outdoor radon concentration, the maximum mean radon concentration at z = 0.5 m height was found to be 6.03 Bq·m−3 in Brand ‘B.H’ which accounts for 13.40% of the worldwide geometric mean indoor radon concentration. Combined with the measurement and simulation results, it can be known that the use of glazed tiles is not the main source of indoor radon, but glazed tile with lower radon exhalation rate is still needed for health purpose.

A unique high natural background radiation area – Dose assessment and perspectives

The biological effects of low dose-rate radiation exposures on humans remains unknown. In fact, the Japanese nation still struggles with this issue after the Fukushima Dai-ichi Nuclear Power Plant accident. Recently, we have found a unique area in Indonesia where naturally high radiation levels are present, resulting in chronic low dose-rate radiation exposures. We aimed to estimate the comprehensive dose due to internal and external exposures at the particularly high natural radiation area, and to discuss the enhancement mechanism of radon. A car-borne survey was conducted to estimate the external doses from terrestrial radiation. Indoor radon measurements were made in 47 dwellings over three to five months, covering the two typical seasons, to estimate the internal doses. Atmospheric radon gases were simultaneously collected at several heights to evaluate the vertical distribution. The absorbed dose rates in air in the study area vary widely between 50 nGy h−1 and 1109 nGy h−1. Indoor radon concentrations ranged from 124 Bq m−3 to 1015 Bq m−3. That is, the indoor radon concentrations measured exceed the reference levels of 100 Bq m−3 recommended by the World Health Organization. Furthermore, the outdoor radon concentrations measured were comparable to the high indoor radon concentrations. The annual effective dose due to external and internal exposures in the study area was estimated to be 27 mSv using the median values. It was found that many residents are receiving radiation exposure from natural radionuclides over the dose limit for occupational exposure to radiation workers. This enhanced outdoor radon concentration might be as a result of the stable atmospheric conditions generated at an exceptionally low altitude. Our findings suggest that this area provides a unique opportunity to conduct an epidemiological study related to health effects due to chronic low dose-rate radiation exposure.

Study of baseline radon levels in the context of a shale gas development

This study reports the results from continuous measurement of indoor and outdoor radon concentrations in the area surrounding an unconventional shale gas exploration site in North Yorkshire, England, prior to the commencement of hydraulic fracturing. Public Health England has monitored the baseline radon levels in homes and in outdoor air in the Vale of Pickering since 2015. The statistical analysis presented here includes three full years (November 2015‐ –December 2018) of indoor and four and half years (October 2015 – April 2019) of outdoor radon measurements.Stratified sampling was used to select 171 dwellings in four areas, with two different radon potential. Statistical analysis confirms that homes in Kirby Misperton and Little Barugh and those in Yedingham are situated in areas with low radon potential, as was predicted by the UK radon potential map. On the other hand, both Pickering and Malton are confirmed as radon Affected Areas.Radon was measured continuously in the outdoor air using a newly developed outdoor kit containing passive radon detectors. The monitoring points were set up at 36 locations in the same local areas as those selected for the indoor monitoring. The results from statistical analysis show that outdoor radon had a different seasonality pattern to indoor radon. The monitoring of outdoor radon levels over the four and half years indicates a year-to-year variation in outdoor radon concentrations with levels fluctuating between 3 and 9 Bq m−3.There was a very good agreement between long-term average radon concentrations measured using passive detectors and using an active AlphaGUARD monitor.

Determination of radon concentrations near mobile towers in selected cities of Babylon governorate, Iraq

Determination of radon concentration in a dwelling is preferred method for monitoring the internal exposure of radiological contaminants. Measurement the concentration of radon and their daughter products in indoor and outdoor of dwelling for Al-Medhatyah and Al-Hashimiyah cities, Babylon governorate near mobile stations were carried out by nuclear track detectors (CR-39) in a bare mode. The results show that the concentrations of indoor radon were found to vary from 85.51 Bq/m3 to 157.48 Bq/m3 with an average value of 131.43 ± 20.71 Bq/m3.This values was lower than the ICRP reco mmended values of (200 – 300 Bq/m3) and thus is within safe limits. The outdoor radon concentrations was vary fro m 100.75 Bq/m3 to 110.06 Bq/m3 with average 105.26 ± 3.8 Bq/m3, the outdoor radon concentration is usually low and less than average indoor levels. The equilibriu m-equivalent radon concentration (EECRN), potential alpha energy concentration (PAEC), annual exposure to potential alpha energy (EP), annual effective dose (AED) and the lung cancer cases per year per million people (CPPP) were calculated.

A low-cost experiment to identify variations in the concentration of environmental radon

Radon is a dangerous radioactive gas that is always present in the environment. It is important that students and society in general are aware of radon as a health hazard. This study describes a simple experiment to measure the variations of radon gas concentration outdoors. We compared the concentration of radon gas in the environment in dry and wet weather conditions and at different times of day. The results show that outdoor radon concentrations are significantly lower, by as much as 50%, during cloudy and rainy conditions.

ROLE OF METEOROLOGY AND LITHOLOGY IN THE TEMPORAL VARIATION OF THE OUTDOOR RADON LEVEL.

The outdoor radon concentration was monitored together with the meteorological parameters at two contrasting complex topographies: sub-Alpine basin (SA) and sub-Mediterranean valley (SM) in winter (December 2017-February 2018) and summer (June-August 2018). The time series for each site and each season are evaluated in three different ways: (i) clear-sky and cloudy condition together, (ii) clear-sky conditions only (cloud cover <20%) and (iii) cloudy condition only (cloud cover >20%), and compared to the expected atmospheric boundary layer (ABL) 'mixing volume' caused by meteorological changes. The results have confirmed the sensitivity of diurnal and seasonal radon concentration to the expected ABL 'mixing volume' at the two selected sites. The relationship is more pronounced in calm clear-sky conditions. Cloudy conditions are associated with fast weather changes, when the ABL is well mixed and hourly mean radon concentrations do not follow the typical diurnal trend.

Assessment of the potential radiation hazard of the Dehmoy tailings pond (Tajikistan) for the population living around it

The paper presents results of radiation monitoring of the Dehmoy tailings pond and the nearest inhabited locality, Goziyon village. It is shown that the average gamma dose rate on the surface of Dehmoy tailings pond reaches 20 μSv/h, density of radon flux from the surface reaches 65 Bq/(m2∙s), and the outdoor radon concentration at the Dehmoy tailings pond varies from 200 to 1000 Bq/m3. It was found that the activity concentration of 238U in the tailing material reaches 980 Bq/kg and the activity concentration of 226Ra reaches 7620 Bq/kg. Potential doses for three hypothetical groups of the population living in the village of Goziyon were assessed and the following sources and ways of exposure were taken into account: external gamma radiation due to soil contamination; internal exposure due to inhalation of 222Rn and its progeny, as well as longlived radionuclides with aerosols from atmospheric air; internal exposure due to ingestion of soil particles. The hypothetical doses range from 0.4 to 17.0 mSv/year. The most significant contributors to the dose are the external gamma radiation and the internal exposure due to inhalation of 222Rn and its progeny. The contribution of internal exposure due to the ingestion of soil particles in the case of working in windy conditions and the lift of dust from the surface of the tailings pond can also be significant. The hypothetical annual doses to three hypothetical groups of the population can be considered as the basis for estimating the safe working time at the tailings pond during its rehabilitation. The calculated dose estimate (up to 17 mSv/year) is rather high and unacceptable compared to the dose limit for the population of 1 mSv/year above the background level.

Assessment of radon concentrations and exposure doses in dwellings surrounding a high capacity gas turbine power station using passive measurements and dispersion modeling

A continuous passive measurement of indoor and outdoor radon R222n, concentration is carried out in the nearby residential areas surrounding a high capacity gas-fired power station. The mean value for indoor measurements was 26.5 ± 1.75 Bq/m3 that is below the worldwide indoor mean of 40 Bq/m3 and for outdoor was 39.4 ± 4.04 Bq/m3 which is higher than the worldwide average outdoor radon concentration of 10 Bq/m3. The annual estimated effective doses were found to vary from 0.54 to 1.05 mSv/y with an average value of 0.67 ± 0.04 mSv/y for indoor dose and from 0.23 to 0.57 mSv/y with an average value of 0.37 ± 0.03 mSv/y for outdoor dose with an overall mean annual effective dose of 1.03 mSv/y. Furthermore, the measured and modeled radon excess levels due to plant operation, both, show that the effect of power plant emission on atmospheric radon levels in the surrounding region is not significant.

Indoor and Outdoor Radon Concentration Levels in Lebanon.

Lebanon's lung cancer rates, among the highest in the Arab region, contribute to the burden of noncommunicable diseases. A number of studies have shown that lung cancer risk increases when smokers vs. nonsmokers exposed to elevated radon levels are compared. This research employs indoor and outdoor space and time concentration surveys across Lebanon, where the smoking rate among the population is among the highest in the world. The distributional properties of measured radon concentration were shown to be lognormal with median indoor and outdoor concentrations of 17 and 10 Bq m, respectively. Standard deviation for indoor concentrations was 1.2 times smaller than its outdoor counterpart, suggesting that weather-related patterns affect outdoor radon concentration variability. No significant spatial association was detected across seasons for indoor and outdoor radon concentrations. Geographical location, proximity to faults, and housing construction material had no significant impact on outdoor and indoor radon concentration variations. When lognormal distributions were used to determine exceedance probability of the recommended reference radon concentration, they were smaller than 0.1%. While exhibiting high seasonal variability, the study shows that radon does not appear to be a public health concern in Lebanon.

Short-term variations of indoor and outdoor radon concentrations in a typical semi-arid city of Northwest China

To obtain basic data for adverse effects of radon (Rn) on human health, indoor and outdoor Rn concentrations were measured using a RAD7 Rn detector from Oct 2015 to Jun 2016 in Xi’an, China. The effects of air quality and ventilation conditions on the short-term variation of Rn concentrations were evaluated in detail. The results show that the outdoor Rn concentrations increased with the increase in degree of air pollution, and the indoor Rn concentrations decreased with the increase in ventilation rate under different airflow patterns. Some effective measures are proposed to reduce the effect of Rn exposure.

Study of the effect of electromagnetic fields on indoor and outdoor radon concentrations

In the present work, the effect of electromagnetic fields produced by high voltage power lines(132kV) and indoor equipments on the indoor and outdoor average radon concentrations in Al-Kazaliya and Hay Al-Adil regions in Baghdad city were studied using CR-39 track detectors and a gauss-meter.Results of measurements of the present study, have shown that the highest value for the indoor average radon concentration (76.56± 8.44 Bq / m3) was recorded for sample A1(Hay Al-Adel) at a distance of (20 m) from the high voltage power lines, while the lowest value for the indoor average radon concentration (30.46 ± 8.44 Bq / m3) was recorded for sample A3 (Hay Al-Adil) at a distance of (50 m) from the high voltage power lines. The indoor gaussmeter measurements were found to be ranged from (30.2 mG) to (38.5 mG). The higest value for outdoor average radon concentration and the highest gaussmeter measurements were found for sample (1), with values (92.63 ±11.2 Bq / m3) and (87.24 ± 2.85 mG), directly under the high voltage power lines respectively, while the lowest outdoor average radon concentration and the lowest gaussmeter measurements were found in sample (4),with values (34.19 ± 6.33 Bq / m3) and (1.16 ± 0.14 Bq / m3),), at a distance of (120 m) from the high voltage power lines respectively. The results of the present work have shown that there might be an influence of the electromagnetic field on radon concentrations in areas which were close to high voltage power lines and houses which have used many electric equipment for a long period of time.