Radon Concentration In Indoor Air Research Articles

On the concentration of radon in a polluted city of the Middle East: An insight into its association with PM levels, air properties, and risk assessment

This study was conducted in Ahvaz city, where the concentrations of radon and airborne particles in 10, 2.5, and 1 micrometers, along with meteorological parameters were measured. The measurements were performed in three educational and therapeutic sampling points at both ground and underground levels during cold and hot seasons. The results showed that in 3.17% of the samples, the concentration of radon exceeded the permissible limit recommended by the Environmental Protection Agency (EPA). Factors affecting the increase of radon concentration in indoor air included cold season, underground sampling points, the number of doors and windows as air dilution factor and air exchange, air pressure, and air humidity. The concentration of particles in the air did not have any effect on radon in the indoor air. The annual effective dose of exposure to radon (DR), the annual effective dose of lung (DE), and the risk of lung cancer cases (LCC) during both cold and hot seasons and at ground and underground levels were lower than the permissible values recommended by the International Committee on Radiological Protection (ICRP). We concluded that the increase of particles is neither the cause nor the source of increased indoor air radon. The findings of the present investigation recommend controlling physical indoor air parameters particularly temperature and relative humidity by proper ventilation systems to mitigate the impact of radon exposure on inhabitants.

광주도시철도 지하역사 내 실내공기 및 지하수 중 라돈농도 분포연구

In this study, the radon concentration in the indoor and underground water of Gwangju subway stations were measured from December 2021 to September 2022 with long-term(more than 90 days) and short-term cycles(48hr). As the measurement places, platform, office, and pump room were selected. Ventilation time and underground water volume are main influencing factors for indoor radon concentration. As a result of study, the long-term radon concentration of indoor air was 17.3 ㏃/㎥ at the platform, 31.0 ㏃/㎥ at the office, and 112.1 ㏃/㎥ at the pump room. The radon concentration per hour in indoor air was measured using Rad-7 with short-term cycle(48 hours), the highest concentration was measured at 53.9 ㏃/㎥ at the platform, 88.9 ㏃/㎥ at the office, and the radon concentration in the office showed about 39% higher than that in the platform. The radon concentration of indoor air in the subway stations was affected by bedrock and depth. As a result of additional measurement for a week in the pump room with a high concentration of radon distribution, it was confirmed that the radon concentration decreased periodically at the operating time of the ventilation system and decreased by 86%. The three sites with a large amount of underground water showed high indoor radon concentration in order. There was a close correlations between the radon concentration of underground water in the subway station and the radon concentration in indoor air.

Indoor radon survey in Greenland and dose assessment

Indoor radon and its decay products are the primary sources of the population's exposure to background ionizing radiation. Radon decay products are one of the leading causes of lung cancer, with a higher lung cancer risk for smokers due to the synergistic effects of radon decay products and cigarette smoking. A total of 459 year-long radon measurements in 257 detached and semi-detached residential homes in southwest and south Greenland were carried out, and a dose assessment for adults was performed. The annual arithmetic and geometric means of indoor radon concentrations was 10.5 ± 0.2 Bq m−3 and 8.0 ± 2.3 Bq m−3 in Nuuk, 139.0 ± 1.0 Bq m−3 and 97.3 ± 2.1 Bq m−3 in Narsaq, and 42.1 ± 0.7 Bq m−3 and 22.0 ± 3.1 Bq m−3 in Qaqortoq. Arithmetic and geometric mean radon concentration of 79.0 Bq m−3 and 50.3 Bq m−3 were estimated for adult, person-weighted living in south Greenland. The total number of detached and semi-detached residential homes where indoor radon is exceeding 100 Bq m−3, 200 Bq m−3, and 300 Bq m−3 is 37 homes (15.0%), 13 homes (5.2%), and 8 homes (3.2%), respectively. A positive correlation between indoor air radon concentrations and underlying geology was observed.The indoor radon contribution to the annual inhalation effective dose to an average adult was 0.5 mSv in Nuuk, 6.5 mSv in Narsaq, 2.0 mSv in Qaqortoq, and 4.0 mSv for south Greenland adult person weighted. The estimated annual average effective dose to adults in Narsaq is higher than the world's average annual effective dose of 1.3 mSv due to inhalation of indoor radon. Cost-efficient mitigation methods exist to reduce radon in existing buildings, and to prevent radon entry into new buildings.

Model to Balance an Acceptable Radon Level Indoors

A theoretical model is presented for balancing an acceptable radon concentration in indoor air. The infiltration of radon from the ground to the indoor air can be controlled by barriers or by lowering the air pressure at the lower zone of the ground slab. Indoor air with a radon concentration higher than that of outdoor air can further be controlled through the effective dilution of indoor air with outdoor air. The theory estimates the allowed radon infiltration from the ground to balance radon at an acceptable level indoors for a given ventilation rate, considering the radon contribution to the indoor air from indoor materials, building materials and the interior. A method using this theory is presented, identifying the necessary airtightness required for a radon barrier to balance the acceptable radon concentration for a building. Barriers include commercially used system solutions, such as bitumen-based radon blockers, wet-room membranes, reinforced fixed mortar pastes, and polyethene membranes. An acceptable indoor radon concentration of between 100 and 300 Bq/m3 in indoor air is used. Barriers are evaluated by their ability to prevent soil gas penetration from the ground in combination with their effect on the building durability, as barriers may create a far more vulnerable building.

Indoor Air Radon Concentration in Premises of Public Companies and Workplaces in Latvia.

Considering the multitudes of people who spend their time working indoors in public premises and workplaces, it is worth knowing what their level of exposure is to natural radioactive radon gas, the second most widespread and dangerous carcinogen for lung cancer development after cigarette smoking. This state-level study covered most of the territory of Latvia and conducted 941 radon measurements with Radtrack2, placed for 4–6 months in the premises of public companies, educational institutions, medical care institutions, etc. The study found that 94.7% of samples did not exceed the national permissible limit (200 Bq/m3), the level at which preventive measures should be initiated. The median value of average specific radioactivity of radon in these premises was 48 Bq/m3 (Q1 and Q3 being 27 and 85 Bq/m3), which is below the average of the European region. Slightly higher concentrations were observed in well-insulated premises with plastic windows and poorer air exchange, mostly in schools (59 (36, 109) Bq/m3) and kindergartens (48 (32, 79) Bq/m3). Industrial workplaces had surprisingly low radon levels (28 (16, 55) Bq/m3) due to strict requirements for air quality and proper ventilation. Public premises and workplaces in Latvia mostly have low radon concentrations in the air, but more attention should be paid to adequate ventilation and air exchange.

RADON-222 CONCENTRATION IN AIR: A CASE STUDY OF AYEDUASE TOWNSHIP, KUMASI, GHANA

Objective: Radon levels in structures (interior environment) were measured in many dwellings and hostels in Ayeduase Township, Ashanti Region, Ghana. The purpose of this study was to quantify radon toxicity in the Ayeduase community, which houses approximately half of the students at Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, and to determine the risk levels for individuals (categorized as infants, children, and adults) living in the community's various suburbs.
 Materials and Methods: Households in Ayeduase had an average of four people per room. The radon in air concentration was measured with a continuous radon monitor using continuous active sampling approach. Multiple measurements were taken at tight space-time intervals over a period of 24 hours. The Continuous Radon Monitor was installed in dwelling rooms in zones where the monitor could record fresh air entering the room. The yearly effective dose was computed using the Mondal 3 Software.
 Results: The continuous sample air radon concentration in Ayeduase Township was found to be in the range of 8.510 0.05607 Bq/m3 to 11.100 0.6379 Bq/m3. The manually computed effective annual dose rate for indoor air radon was 0.3494 mSv/year to 0.4558 mSv/year for babies, 0.0683 mSv/year to 0.0891 mSv/year for children, and 0.0559 mSv/year to 0.0729 mSv/year for adults. The comparative results from the Mondal 3 Software showed that the effective annual dose rate for indoor air ranged from 0.32 mSv/year to 0.37 mSv/year, with an average of 0.36 mSv/year for infants, 0.11 mSv/year to 0.14 mSv/year, with an average of 0.12 mSv/year for children, and 0.084 mSv/year to 0.097 mSv/year, with an average of 0.94 mSv/year for adults.
 Conclusion: Ayeduase's radon toxicity profile in terms of air showed distinct features. The maximum value of indoor air radon concentration level determined was lower than the global average value of 40 Bq/m3 of indoor radon concentration level and also lower than the reference level of 100 Bq/m3. In Ayeduase, the estimated average effective dosage over a year for babies, children, and adults were lower than the 1.2 mSv/year indicated by ICRP Publication 126.
 Recommendation: Radon toxicity due to water and soil sources are required to access the total toxicity levels in the township. Reliable evaluation of the potential for human exposure to radon depends in part on the reliability of supporting analytical data from environmental samples and biological specimens is highly recommended, as well as, concentrations of radon in unpolluted atmospheres and in pristine surface waters are typically within the limits of current analytical methods.

Results of Measurements of Radon Volume Activity in Azerbaijan

The procedures and results of measuring radon volume activity (concentration) in Azerbaijan (in residential and industrial premises, soil air, thermal waters, and mud volcanoes) are described. It was established that indoor radon concentrations vary in a wide range: from 20 to 1110 Bq/m3; about 7% of the total amount of measurements exceed the maximum permissible limits in Azerbaijan (200 Bq/m3). Based on these data, maps of the distribution of indoor radon volume activity in Azerbaijan are constructed for the first time. The enhanced radon concentrations are confined to fold-mountain massifs of Greater and Lesser Caucasus and Talysh. Results of measurements of radon concentrations in indoor air are very consistent with the data of radon content in soil air. The content of radon in thermal waters is not high generally, except for the waters of one carbon source in the Talysh region, where its concentration is above the maximum permissible level accepted for drinking water. Enhanced values of radon volume activity in mud volcanoes (especially in gases released from the gryphons) have also been revealed. Based on the complex processing of the data, a conclusion is drawn about the natural origin of enhanced values of radon volume activity in this part of the examined residential premises in Azerbaijan.

Short-term characterization of the indoor air radon concentration in a XII century monastery converted into a school building

An ancient monastery placed in Ponte de Lima, an inner village in Alto Minho region, North of Portugal, was monitored in order to assess radon gas concentrations. The aim of this paper is to perform a short-term radon gas characterization to assess the radon risk in a school building and therefore propose adequate mitigation strategies. The experimental campaign took place during spring and summer of 2017 and was carried out in 2 complementary steps involving 17 different sites. This study revealed that the radon concentration levels are above the legal limit of 400 Bq.m-3, in 77% of the samples. The value rises to 86% when Euratom Directive limit of 300 Bq.m-3 is considered. Furthermore, the results obtained that indoor radon concentration varies with the occupancy of the rooms, since it is evident that the human ventilation actions have a considerable impact on the reduction of its concentration.

Analysis of simultaneous time series of indoor, outdoor and soil air radon concentrations, meteorological and seismic data

Abstract It is well known that the temporal dynamic of indoor and outdoor radon concentrations show complex patterns, which are partly not easy to interpret. Clearly, for physical reasons, they must be related to possibly variable conditions of radon generation, migration and atmospheric dispersion and accumulation. The aim of this study was to analyse long-time series of simultaneously measured indoor and outdoor radon concentrations, together with environmental quantities, which may act as control variables of Rn. The study was performed in Chiba, Japan, using two ionization chambers for parallel indoor and outdoor radon concentrations measurements over 4 years. Meteorological and seismic data were obtained from the Japan Metrological Agency (JMA).

Preliminary research to determine the distribution characteristics of indoor air radon concentration in a hot spring bath

Preliminary research to determine the distribution characteristics of indoor air radon concentration in a hot spring bath

STATISTICAL ANALYSIS OF TEMPORAL VARIATIONS IN INDOOR RADON DATA USING AN ADAPTED RESPONSE SURFACE METHOD

Temporary variations in indoor radon data (IRD), comprising radon concentration (RC), air temperature, relative humidity and barometric pressure were monitored hourly over a period of two months in a bungalow house in Abeokuta, Nigeria. A total of 1510 data was assembled and analyzed statistically using Shapiro-Wilk for normality test, response surface method (RSM) and adapted response surface method (ARSM) to investigate and model the influence of the meteorological parameters on the variations of RC in indoor air. The overall results showed that RC varies widely over time and correlates positively with relative humidity and temperature, but negatively with barometric pressure. Specific results of the two response surface methods were compared and contrasted and the multiple linear regression model of the ARSM was highlighted and established as the appropriate method for analyzing IRD. ARSM was presented in an easily reusable form that can easily be adopted by researchers and data analysts.ª¤?

Evaluation of Radon Concentration in Indoor Air and Groundwater in Shahjahanpur, Uttar Pradesh, India

Evaluation of Radon Concentration in Indoor Air and Groundwater in Shahjahanpur, Uttar Pradesh, India

Radon concentration in air and external gamma dose rate: is there a correlation?

We checked the existence of correlations between experimentally determined radon concentration in indoor air and gamma dose rate, in different environments: residences, workplaces in subway stations and radiotherapies, and a gold mine. Except for the mine environment, where a linear correlation (r 2 = 0.86) was obtained with statistical significance, we found no correlations between those quantities. Both radiation sources are originated from natural radionuclides, nonetheless the observation of correlations depends on various conditions, as we discuss here.

Radon exhalation from sub-slab aggregate used in home construction in Canada

Exposure to elevated levels of radon in homes has been shown to result in an increased risk of developing lung cancer. The two largest contributors to indoor radon are radon in soil gas, formed from the rocks and soil surrounding the home, and building materials such as aggregate. This study measured the surface radon exhalation rates for 35 aggregate samples collected from producers across Canada. The radon exhalation rates ranged from 2.3 to 479.9 Bq m(-2) d(-1), with a mean of 80.7±112 Bq m(-2) d(-1). Using a simple, conservative analysis, the aggregate contribution to radon concentrations in an unfinished basement was determined. The maximum estimated radon concentration was 32.5±2.7 Bq m(-3), or ~16 % of the Canadian Radon Guideline. It can be concluded that under normal conditions radon exhalation from aggregate contributes very little to the total radon concentration in indoor air.

Estimation of annual effective dose due to Radon level in indoor air and soil gas in Hamirpur district of Himachal Pradesh

Indoor air and soil gas radon measurements are simultaneously performed in Hamirpur district of Himachal Pradesh using RAD7, a solid state alpha detector. The study is performed for the estimation of radon level and annual effective dose for indoor air. Different locations are selected and it is found that the variation of radon concentration in indoor air and soil gas in Hamirpur region ranges from 35Bqm−3 to 956Bqm−3 and 35 to 2280Bqm−3 having mean values 189.43Bqm−3 and 462.56Bqm−3 respectively. From indoor air, the total annual effective dose is calculated and it varies from 0.88mSvy−1 to 24.09mSvy−1 with mean value of 4.77mSvy−1. In general, it is found that the annual effective dose limit was within the recommended reference level (3mSvy−1to 10mSvy−1) of the world organisations. A good correlation between radon concentration in air and soil gas is observed.

Physical Factors Affecting the Interior Radon-Concentrations

Researchers have realized that radon-contaminated air inside buildings is a principal way of human exposure to certain healthy-risks. A model is developed to estimate radon concentrations which consider various parameters: in indoor air radon (radon-222) concentration, air permeability of ground, air pressure difference between outdoor and indoor at ground level, ventilation of building ground and number of air changes per hour due to ventilation. The radon-222 transport into building might dominated by diffusion, pressure driven flow or/and a mixture of both depending on the actual values of the various parameters. So, in several and regular periods of time: January, April, July and October, radon-222 concentrations have been measured in ten rooms of five elementary schools and in five rooms of one high school at Qena city (Upper Egypt). This has been carried out using alpha scintillation counters. We have noticed that in three rooms the value has exceeded 200 Bqm -3 at the basement and only one room at the first floor, and all values have changed with respect to time and localization: They have decreased from July to January and from basement to first floor. For example, radon-222 concentrations obtained by exposing track detectors varied in the range from 20 Bqm-3 up to 100 Bqm-3. The experimental results of the present work have been well fitted with the presented model (calculations) which supports the validity of the presented model. So, to decrease the level of indoor air radon-222 concentrations and to reduce its harmful effects it is recommended to follow the suggestions in the present study and to limit as possible the use of ceramic in the building construction, increase the hours of ventilation and to restrict the use of underground floors in buildings, the underground Metro and garage parking should be carefully (and even mandatory) ventilated.

Radon in indoor concentrations and indoor concentrations of metal dust particles in museums and other public buildings

The aim of this study was to evaluate the public and occupational exposure to radon and metal-bearing particles in museums and public buildings located in the city of Rio de Janeiro, Brazil. For this study, four buildings were selected: two historic buildings, which currently house an art gallery and an art museum; and two modern buildings, a chapel and a club. Integrated radon concentration measurements were performed using passive radon detectors with solid state nuclear track detector-type Lexan used as nuclear track detector. Air samplers with a cyclone were used to collect the airborne particle samples that were analyzed by the particle-induced X-ray emission technique. The average unattached-radon concentrations in indoor air in the buildings were above 40 Bq/m(3), with the exception of Building D as measured in 2009. The average radon concentrations in indoor air in the four buildings in 2009 were below the recommended reference level by World Health Organization (100 Bq/m(3)); however, in 2011, the average concentrations of radon in Buildings A and C were above this level, though lower than 300 Bq/m(3). The average concentrations of unattached radon were lower than 148 Bq/m(3) (4pCi/L), the USEPA level recommended to take action to reduce the concentrations of radon in indoor air. The unattached-radon average concentrations were also lower than the value recommended by the European Union for new houses. As the unattached-radon concentrations were below the international level recommended to take action to reduce the radon concentration in air, it was concluded that during the period of sampling, there was low risk to human health due to the inhalation of unattached radon in these four buildings.

Indoor radon in Tunisian spas

Indoor radon concentrations were measured in four well-known spas of Tunisia using nuclear track detectors. The radon concentrations in these spas were found to be in the range of 19 - 870 Bq.m-3 . The equilibrium factor F between radon and its progeny was found to vary in the range of 0.2 - 0.5, depending upon the ventilation rates within the buildings of the spas. Using the exposure-dose conversion factor, the effective doses to patients and workers were estimated and the dose was found to vary in the range 3.7 × 10-3 - 12.5 × 10-3 mSv.y-1 and 0.45 - 1.5 mSv.y-1 for patients and workers, respectively. These values are well inside the limit recommended for the annual dose limit of 20 mSv.y-1 for an occupational worker. The radium content in the groundwater of all four spas was measured and the results showed no correlation between the 226 Ra concentration in water and radon concentration in indoor air of the investigated spas.

Radon (222Rn) concentration in indoor air near the coal mining area of Nui Beo, North of Vietnam

Concentrations of radioactive radon gas (222Rn) were measured using passive monitors based on LR115 solid state track detectors during June–July 2010 in indoor air of dwellings in the Nui Beo coal mining area, mostly in Cam Pha and Ha Long coastal towns, Quang Ninh province, in the North of Vietnam. Global results of 222Rn concentrations indoors varied from ≤6 to 145 Bq m−3 averaging 46 ± 26 Bq m−3 (n = 37), with a median value of 47 Bq m−3. This was similar to outdoor 222Rn concentrations in the region, averaging 43 ± 19 Bq m−3 (n = 10), with a median value of 44 Bq m−3. Indoor 222Rn concentrations in the coastal town dwellings only were in average lower although not significantly different from indoor 222Rn concentrations measured at the coal storage field near the harbor, 67 ± 4 Bq m−3 (n = 3). Furthermore, there was no significant difference in the average 222Rn concentration in indoor air measured in the coastal towns region and those at the touristic Tuan Chau Island located about 45 km south of the coal mine, in the Ha Long Bay. The indoor 222Rn concentration in a floating house at the Bai Tu Long Bay, and assumed as the best estimate of the baseline 222Rn in surface air, was 27 ± 3 Bq m−3 (n = 3). Indoor average concentration of 222Rn in dwellings at the Ha Noi city, inland and outside the coal mining area, was determined at 30 Bq m−3. These results suggest that 222Rn exhalation from the ground at the Nui Beo coal mining area may have contributed to generally increase 222Rn concentration in the surface air of that region up to 1.7 times above the baseline value measured at the Bai Tu Long Bay and Ha Noi. The average indoor concentration of 222Rn in Cam Pha–Ha Long area is about one-third of the value of the so-called Action Level set up by the US EPA of 148 Bq m−3. Results suggest that there is no significant public health risk from 222Rn exposure in the study region.

Development of a model for radon concentration in indoor air

A model is developed for calculation of the radon concentration in indoor air. The model takes into account various important parameters, e.g. radon concentration in ground, radon diffusion resistance of radon barrier, air permeance of ground, air pressure difference between outdoor ground and indoor at ground level, ventilation of the building ground and number of air changes per hour due to ventilation. Characteristic case studies are depicted in selected 2D and 3D graphical plots for easy visualization and interpretation. The radon transport into buildings might be dominated by diffusion, pressure driven flow or a mixture of both depending on the actual values of the various parameters. The results of our work indicate that with realistic or typical values of the parameters, most of the transport of radon from the building ground to the indoor air is due to air leakage driven by pressure differences through the construction. By incorporation of various and realistic values in the radon model, valuable information about the miscellaneous parameters influencing the indoor radon level is gained. Hence, the presented radon model may be utilized as a simple yet versatile and powerful tool for examining which preventive or remedial measures should be carried out to achieve an indoor radon level below the reference level as set by the authorities.