Numerical investigation of radon dispersion and dose assessment for typical ventilation schemes with an air purifier

2020 ◽  
Vol 30 (1) ◽  
pp. 114-128
Author(s):  
Dong Xie ◽  
Chenhua Wang ◽  
Chuck W Yu ◽  
Hanqing Wang
Keyword(s):  
Mechanical Ventilation ◽  
Effective Dose ◽  
Natural Ventilation ◽  
Indoor Radon ◽  
Radioactive Decay ◽  
Dose Assessment ◽  
Radiological Protection ◽  
Ventilation Condition ◽  
Air Supply ◽  
Air Purifier

Radon is a radioactive pollutant that could pose hazards to the surrounding environment and people due to its radioactive decay progenies. In this study, numerical simulations of radon dispersion were conducted under natural and mechanical ventilation with an air-purifier for radon. Factors such as the air supply speed, position and air supply angles of the purifier were considered. Results showed that the increase in the air supply speed from the purifier was an effective solution to reduce indoor radon pollution. The effect was better when the purifier was in the middle of the room. The purification effect was similar when the air supply changed under natural ventilation, while purification function was more effective when the air supply angle was 60° under the mechanical ventilation condition. An effective dose estimation involving typical ventilation schemes with radon purifier was evaluated. Using this approach, the radiation effect on occupants was computed. The calculated effective dose was 0.9 mSv y−1 when the air supply speed of the purifier was 0.2 m s−1 under natural ventilation. As a result, the effective dose calculated was under the annual effective dose limit of 3–10 mSv y−1 recommended by the International Commission on Radiological Protection (ICRP) for public exposure.

STUDY OF 222RN CONTINUOUS MONITORING TIME SERIES AND DOSE ASSESSMENT IN SIX EUROPEAN CAVES

2020 ◽  
Vol 191 (2) ◽  
pp. 233-237
Author(s):  
F Ambrosino ◽  
L Thinová ◽  
M Briestenský ◽  
C Sabbarese
Keyword(s):  
Effective Dose ◽  
Natural Ventilation ◽  
Annual Effective Dose ◽  
Working Hours ◽  
Health Impact ◽  
Dose Assessment ◽  
Radiological Protection ◽  
Radon Activity ◽  
Clastic Sediments ◽  
Effective Doses

Abstract The present work aims to assess the effective doses from long-term continual radon monitoring in six European caves (Slovenia, Slovakia and the Czech Republic), including influencing environmental factors. Caves are important radiation protection subjects because of elevated radon activity concentration (~kBq/m3), mostly due to the low natural ventilation. The sources of radon gas are most often underground rock layers and clastic sediments. The radon activity concentrations show seasonal variations, for which the outside temperature is the main driving force. The human health impact due to the radon inhalation in monitored caves was estimated through the annual effective dose, using the methodology provided by the International Commission on Radiological Protection (ICRP Publication 137). The annual effective dose could reach several tens of mSv, depending on the working hours spent in the underground.

Numerical Evaluation of Ventilation Efficiency of Window Type Ventilation Systems

2019 ◽  
Vol 27 (03) ◽  
pp. 1950027
Author(s):  
Young Kwon Yang ◽  
Min Young Kim ◽  
Jin Woo Moon ◽  
Jin Chul Park
Keyword(s):  
Mechanical Ventilation ◽  
Indoor Air ◽  
Numerical Evaluation ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Adverse Pressure Gradient ◽  
Building Energy ◽  
Window Opening ◽  
Ventilation Efficiency ◽  
Air Purifier

Ventilation in buildings is the simplest and most convenient way to purify indoor air. However, when the ventilation is not enough due to natural ventilation, it should be cleaned by mechanical ventilation or air purifier. This process requires building energy. Therefore, it is possible to save the energy of the building by merely increasing the natural ventilation efficiency. This study conducted airflow analysis simulations to investigate the effects of changes in the shape of ventilation openings and louvers on the ventilation efficiency of a window ventilation system. The streamlined window opening exhibited a greater increase in airflow (41.3%) than did the conventional window (24.3%) for the ventilation model with four openings. It was also observed that flow separation and wakes were generated by the adverse pressure gradient arising from the increased airflow speed when a louver was employed. Based on these results, it can be concluded that using a louver as a wind augmentation device is an obstacle to improving the airflow in a window ventilation system.

scholarly journals Determination of radon levels in dwellings and social objects and evaluation annual effective dose from inhalation of radon in Stepnogorsk area Northern Kazakhstan

2020 ◽  
Vol 4 (4) ◽  
pp. 343-349
Author(s):  
D.S. Ibrayeva ◽  
M.N. Aumalikova ◽  
K.B. Ilbekova ◽  
M.M. Bakhtin ◽  
P.K. Kazymbet
Keyword(s):  
Effective Dose ◽  
Annual Effective Dose ◽  
Noble Gas ◽  
Indoor Radon ◽  
Radioactive Decay ◽  
Annual Dose ◽  
Natural Radiation ◽  
Mining Sites ◽  
Decay Products ◽  
Activity Concentrations

Radon is a noble gas that is one of the natural radioactive decay products of radium resulting from the disintegration of uranium. Humans are exposed to sources of natural radiation activity, being radon and its progeny breathing air responsible for more than 50% of the annual dose received from natural radiation. The aim of this study was to determine the radon concentration in the air in settlements’ dwellings and social objects and calculate the annual effective dose of population from radon on the territory mining activities in Stepnogorsk area. The study has shown that activity concentrations of indoor radon in the buildings ranged from 8 to 870 Bq · m−3 in Aqsu, 3-540 Bq · m−3 in Kvartsitka located close to former gold mining sites. The Einh corresponding to the activity concentrations ranged from 1-27 mSv · y−1 received by the settlements’ public. The highest value of Einh in Aqsu School reaches up to 68 mSv · y−1 received by the critical group of public was found at the territory of former mining the Stepnogorsk area. The results of this study show significant radiation hazards in Aqsu School which located at the territory of former mining site, and there is evidence of radon health risk to the members of the public.

scholarly journals Experimental study on indoor environment quality in a naturally ventilated classroom of a university using natural ventilation and ventilation fan

2020 ◽  
Vol 165 ◽  
pp. 04082
Author(s):  
Jie Zong ◽  
Wenjun He ◽  
Lingna Wang ◽  
Hongkai Chai ◽  
Yingying Zhao ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Indoor Environment ◽  
Natural Ventilation ◽  
Carbon Dioxide Concentration ◽  
Co2 Concentration ◽  
Environment Quality ◽  
Air Supply ◽  
Indoor Environment Quality ◽  
Jinan City ◽  
Ventilation Fan

Strengthening indoor ventilation is an important measure to improve air quality. In transitional season between spring and summer, a university classroom in Jinan city was selected as the research object. Mechanical air supply is adopted to solve the problem of insufficient fresh air or excessive carbon dioxide concentration in the classroom. CO2 concentration and air change rates are compared in natural ventilation and mechanical classrooms. The experiment shows that the indoor CO2 concentration of mechanical ventilation classroom is relatively low. Under natural ventilation, mechanical ventilation and mixed ventilation, the average air change rates were 1.05 h-1, 1.83 h-1 and 2.7 h-1, respectively. According to the statistics analysis of the questionnaire, 72.84% of the students hope to install the mechanical ventilation in the classroom.

Indoor radon measurement and effective dose assessment of 150 apartments in Mashhad, Iran

2011 ◽  
Vol 184 (2) ◽  
pp. 1085-1088 ◽  
Author(s):  
Ali Asghar Mowlavi ◽  
Maria Rosa Fornasier ◽  
Ailreza Binesh ◽  
Mario de Denaro
Keyword(s):  
Effective Dose ◽  
Indoor Radon ◽  
Dose Assessment ◽  
Radon Measurement

Workplace indoor radon survey in Nova Scotia, Canada

2013 ◽  
Vol 56 (01) ◽  
pp. 13-18
Author(s):  
H. E. Mersereau ◽  
A. Scott ◽  
K. Whelan
Keyword(s):  
Mechanical Ventilation ◽  
Nova Scotia ◽  
Indoor Radon ◽  
Radioactive Decay ◽  
Participation Rate ◽  
Sampling Period ◽  
Radioactive Materials ◽  
Naturally Occurring ◽  
Health Canada ◽  
Radon Survey

Radon is a naturally occurring gas emitted from the radioactive decay of uranium. A systematic radon assessment carried out in Nova Scotia (NS) has shown that many areas in the province are radon prone due to elevated levels of natural radioactivity in soil. Very little occupational radon data is available for NS, so this survey was designed to collect basic radon information from several NS workplaces in a nonrandomized fashion. Twenty three workplaces were contacted for participation in the study, and 21 participated for a 91% participation rate. The survey was conducted by placing 170 alpha track detectors within 21 workplaces for a minimum three-month sampling period and comparing the results with the Canadian Guidelines for the Management of Naturally Occurring Radioactive Materials (NORM) and the Health Canada Guidelines. The results indicated that 19 of the workplaces had average radon concentrations below 150 Bqm−3, with only two workplaces having at least one measurement above this concentration. Both workplaces with elevated measurements had fewer than 25 employees and a lack of mechanical ventilation. The range of results for all workplaces was from −2.0 to 202.1 Bqm−3, with an overall average of 25.7 Bqm−3 for all workplaces. Future surveys should focus on small workplaces (<25 employees) with a lack of mechanical ventilation.

The 222Rn and 220Rn concentrations in some dwellings of Mandya city and its surroundings, Karnataka, India

2020 ◽  
pp. 1420326X2093159
Author(s):  
Kesthur Naraseyappa Narasimhamurthy ◽  
Godekere Visweswaraiah Ashok ◽  
Thuruganur Siddaiah Shashi Kumar ◽  
Ningaiah Nagaiah
Keyword(s):  
Respiratory Tract ◽  
Mass Balance ◽  
Effective Dose ◽  
Balance Equation ◽  
General Public ◽  
Annual Effective Dose ◽  
Indoor Radon ◽  
Radiological Protection ◽  
Mass Balance Equation ◽  
Mean Values

The measurement of 222Rn and 220Rn concentrations in air was carried out in 50 dwellings belonging to 20 locations in and around Mandya city, Karnataka. Annual mean values of 222Rn and 220Rn concentrations were found to be 22.4 ± 1.5 and 24.1 ± 1.8 Bq m−3, respectively. The total annual effective dose received by the general public due to radon and thoron was found to be 1.36 ± 0.08 mSv y−1. The doses to different organs and tissues were calculated using the International Commission on Radiological Protection (ICRP) model of the respiratory tract and inter-comparison was made. The flooring, roofing type and age of the buildings were noted and the radon levels with respect to these parameters were analysed and discussed. An attempt was made to predict the indoor radon levels in dwellings using the existing model which was based on the mass balance equation and the results were compared with measured values.

Ventilation Measurement and Simulation Optimization for Aerobic Composting Workshop of a Large Sludge Treatment Engineering

2012 ◽  
Vol 170-173 ◽  
pp. 2727-2731
Author(s):  
Kai Zhen Zhu ◽  
Jian Fei Zhang ◽  
Shuang Jia ◽  
Xu Du ◽  
Li Juan Zhang
Keyword(s):  
Mechanical Ventilation ◽  
Energy Consumption ◽  
Simulation Optimization ◽  
Breathing Zone ◽  
Aerobic Composting ◽  
Ammonia Content ◽  
Sludge Treatment ◽  
Ventilation Condition ◽  
Air Supply ◽  
Better Than

Based on measured ventilation condition in the built aerobic composting plant of large sludge treatment engineering,using the methord of CFD, four kinds of scheme for the new aerobic composting plant were analysed,which contain two types of ventilation(natural air supply mechanical exhaust and mechanical air mechanical ventilation)and two kinds of supply air rates (4x105m3/h and 8x105m3/h). Studies have shown that the methord of mechanical air supply and exhaust is better than the original natural air mechanical exhaust in this plant; The methord of mechanical air supply and exhaust is recommended to reduce ammonia content for personal breathing zone and ventilation energy consumption.

scholarly journals Age-dependent dose assessment of uranium intake from bottled water in Punjab state, India

2020 ◽  
Vol 20 (7) ◽  
pp. 2794-2803
Author(s):  
Vikas Duggal
Keyword(s):  
Effective Dose ◽  
Uranium Concentration ◽  
Annual Effective Dose ◽  
Age Groups ◽  
Dose Assessment ◽  
Radioactive Material ◽  
World Health ◽  
Human Consumption ◽  
Radiological Protection ◽  
Age Dependent

Abstract Uranium, both a radioactive material and a heavy metal, poses a health risk due to its radiological properties and chemical toxicity. In the present study, uranium concentration and relative age-dependent effective dose have been measured in 27 commercial brands of bottled waters collected randomly from different districts of Punjab, India. Uranium concentration varied from 0.19 to 9.29 μg l−1 with a mean value of 1.58 μg l−1, a standard deviation of 1.95 μg l−1 and a median of 0.82 μg l−1. Uranium concentrations in all the samples were found to be lower than the World Health Organization (WHO) and U.S. Environmental Protection Agency (USEPA) prescribed limit of 30 μg l−1 and AERB India proposed a radiological based limit of 60 μg l−1. Based on permissible limits, all the samples were suitable for human consumption. The annual effective dose was determined by taking the recommended water intake values of different age groups. The mean annual effective dose for all age groups was well within the International Commission on Radiological Protection (ICRP) recommended reference dose level of 1 mSv y−1. The highest dose was calculated for infants, which makes them the most crucial group of the population.

Effect of Ventilation Type on Radon Concentration at Places of Work

1994 ◽  
Vol 56 (1-4) ◽  
pp. 61-63 ◽  
Author(s):  
E. Oksanen
Keyword(s):  
Child Care ◽  
Radon Concentration ◽  
Natural Ventilation ◽  
Indoor Radon ◽  
Exhaust System ◽  
Air Supply ◽  
Care Facilities ◽  
Child Care Facilities ◽  
Radon Concentrations

Abstract Indoor radon (222Rn) concentrations were measured at 76 child care facilities and 36 schools in southern Finland. The buildings had three different types of ventilation systems: mechanical air supply and exhaust, mechanical exhaust, and natural ventilation, the first being most common. The effect of the ventilation type on the long-term radon concentration was studied in child care facilities. The radon concentrations were highest in the naturally ventilated buildings. The mechanical air supply and exhaust system maintained the lowest values in cold wintertime. In school buildings both the long-term radon concentration and short-term radon and daughter concentrations were measured. The correlation of the ventilation type and the radon concentration was not obvious in this group of measurements. But the radon concentrations and the equilibrium factors were highest in buildings with natural ventilation. Radon concentrations were generally lower during the working hours than during the one-month period, as expected.

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