scholarly journals A Deterministic Model for Estimating Indoor Radon Concentrations in South Korea

2019 ◽  
Vol 16 (18) ◽  
pp. 3424
Author(s):  
Ji Hyun Park ◽  
Cheol Min Lee ◽  
Dae Ryong Kang
Keyword(s):  
Mass Balance ◽  
Building Materials ◽  
Deterministic Model ◽  
Indoor Radon ◽  
Measurement Data ◽  
High Concentration ◽  
Actual Measurement ◽  
Factors Affecting ◽  
Radon Concentrations

Estimating long-term exposure to indoor radon is necessary to determine the effects of indoor radon exposure on health. However, measuring long-term exposure to radon is labor intensive and costly. While developing models for estimating indoor radon concentrations are very difficult and unrealistic due to the many factors affecting radon concentrations, several studies have attempted to estimate indoor radon concentrations with mathematical models based on mass balance equations. However, these models are only applicable to specific regions or situations, and some require actual measurement data. This study sought to develop a widely applicable model for estimating mean annual indoor radon concentrations in actual residences considering seasonal variations in indoor radon. The model is based on a mass balance equation using data on geographical factors, building characteristics, meteorological factors, and nationwide radon surveys. The primary factor in our model is the infiltration factor, which can vary according to region, building materials, cracks, floor type, etc. In this study, infiltration factor was calculated according to the type of housing and groundwater usage, and the results thereof were applied to estimate indoor radon concentrations. Overall, measured concentrations and estimates of indoor radon concentrations using the infiltration factor were similar. This model showed better performance than our previous model, except for a few high concentration residences.

scholarly journals Indoor radon concentration and a diffusion model in dwellings situated in a subalkaline granitoid area, Southern Brazil

2021 ◽  
Vol 80 (17) ◽  
Author(s):  
G. Romero-Mujalli ◽  
A. Roisenberg ◽  
A. Cordova-Gonzalez ◽  
P. H. P. Stefano
Keyword(s):  
Diffusion Model ◽  
Indoor Radon ◽  
Southern Brazil ◽  
High Concentration ◽  
Indoor Radon Concentration ◽  
One Dimensional ◽  
Environmental Limits ◽  
Radon Measurements ◽  
Cr 39 Detectors

AbstractRadon (Rn), a radioactive element, has especial interest in medical geology because long-term exposure to high concentration is related to lung cancer. In this study, outdoor and indoor radon measurements were conducted in dwellings of the Piquiri Syenite Massif, located in southern Brazil, given the relative high Rn content in soils of this region. Measurements were done using CR-39 detectors and placing them inside and outside dwellings. Moreover, a one-dimensional diffusion model was performed in order to quantify the natural transport of Rn to the air in confined and aerated environments. Results indicate that the region presents relatively low air Rn concentrations, within the environmental limits; however, the health risk might increase in confined and ill-ventilated environments because of transfer from soil and exhalation from ornamental rock-material often found inside dwellings. The main north facies of the syenite, where most of the rock extractions are located, was found to have the highest air Rn concentration because of the higher soil Rn concentration, compared to other facies of the syenite.

Long-Term NOx Emission Behavior of Heavy Duty Gas Turbines: An Approach for Model-Based Monitoring and Diagnostics

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Moritz Lipperheide ◽  
Frank Weidner ◽  
Manfred Wirsum ◽  
Martin Gassner ◽  
Stefano Bernero
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Mean Squared Error ◽  
Combustion Process ◽  
Measurement Data ◽  
Prediction Method ◽  
Heavy Duty ◽  
Actual Measurement ◽  
Input Parameters

Accurate monitoring of gas turbine performance is a means to an early detection of performance deviation from the design point and thus to an optimized operational control. In this process, the diagnosis of the combustion process is of high importance due to strict legal pollution limits as aging of the combustor during operation may lead to an observed progression of NOx emissions. The method presented here features a semi-empirical NOx formulation incorporating aging for the GT24/GT26 heavy duty gas turbines: Input parameters to the NOx-correlation are processed from actual measurement data in a simplified gas turbine model. Component deterioration is accounted for by linking changes in air flow distribution and control parameters to specific operational measurements of the gas turbine. The method was validated on three different gas turbines of the GE GT24/GT26 fleet for part- and baseload operation with a total of 374,058 long-term data points (5 min average), corresponding to a total of 8.5 years of observation, while only commissioning data were used for the formulation of the NOx correlation. When input parameters to the correlation are adapted for aging, the NOx prediction outperforms the benchmark prediction method without aging by 35.9, 53.7, and 26.2% in terms of root mean square error (RMSE) yielding a root-mean-squared error of 1.27, 1.84, and 3.01 ppm for the investigated gas turbines over a three-year monitoring period.

Long-Term NOx Emission Behavior of Heavy Duty Gas Turbines: An Approach for Model-Based Monitoring and Diagnostics

2017 ◽  
Author(s):  
Moritz Lipperheide ◽  
Frank Weidner ◽  
Manfred Wirsum ◽  
Martin Gassner ◽  
Stefano Bernero
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Mean Squared Error ◽  
Combustion Process ◽  
Measurement Data ◽  
Prediction Method ◽  
Heavy Duty ◽  
Actual Measurement ◽  
Input Parameters

Accurate monitoring of gas turbine performance is a means to an early detection of performance deviation from the design point and thus to an optimized operational control. In this process, the diagnosis of the combustion process is of high importance due to strict legal pollution limits as aging of the combustor during operation may lead to an observed progression of NOx emissions. The method presented here features a semi-empirical NOx formulation incorporating aging for the GT24/GT26 heavy duty gas turbines: Input parameters to the NOx-correlation are processed from actual measurement data in a simplified gas turbine model. Component deterioration is accounted for by linking changes in air flow distribution and control parameters to specific operational measurements of the gas turbine. The method was validated on three different gas turbines of the GE GT24/GT26 fleet for part- and baseload operation with a total of 374,058 long-term data points (5 min average), corresponding to a total of 8.5 years of observation, while only commissioning data was used for the formulation of the NOx correlation. When input parameters to the correlation are adapted for aging, the NOx prediction outperforms the benchmark prediction method without aging by 36.7, 54.0 and 26.7 % in terms of RMSE yielding a root-mean-squared error of 1.26, 1.81 and 2.99 ppm for the investigated gas turbines over a three year monitoring period.

scholarly journals CONCENTRATIONS OF INDOOR AND SOIL RADON IN LITHUANIA/RADONAS GRUNTO ORE IR PATALEOSE LIETUVOJE

1998 ◽  
Vol 4 (4) ◽  
pp. 316-321
Author(s):  
Kęstutis Gasiūnas ◽  
Albinas Mastauskas ◽  
Gendrutis Morkūnas
Keyword(s):  
Building Materials ◽  
Indoor Radon ◽  
Average Concentration ◽  
Existing Buildings ◽  
Soil Air ◽  
Naturally Occurring ◽  
Naturally Occurring Radionuclides ◽  
Radon Risk ◽  
Action Levels ◽  
Radon Concentrations

Uranium and its daughters including Ra-226 are naturally present in the Earth's crust and other environmental bodies. During decay of Ra-226 radioactive noble gas radon is produced. This gas emanates to the atmosphere from solid matrixes containing Ra-226. It causes a special problem connected with the fact that radon accumulates in the closed spaces of buildings. Increased concentrations of radon indoors in many cases are the significant source of human exposure to ionizing radiation. Radon daughters having been deposited in the airways of human lungs are the source of alpha particles which irradiates the inner surface of airways. Since radiation quality of alpha radiation is high and small volumes of tissues are being irradiated, the influence of indoor radon as a source of ionizing radiation is significant. In order to forecast indoor radon concentrations and to take necessary remedial (in existing buildings) or prevention (in new buildings) measures, the main sources of indoor radon should be known in each country or geographical region. It may be soil, building materials, water and natural gas. It has been determined that the main source of indoor radon in Lithuania is soil. Permanent investigations of radionuclide content of building materials used or manufactured in Lithuania have not revealed any building materials with concentrations of naturally occurring radionuclides exceeding maximum permitted levels determined by the Lithuanian Hygienic Standards HN 40-1994. These investigations are performed by means of gamma spectrometry using the Ge spectrometer by Oxford after sample grinding and drying. A short review of radon risk mapping techniques used in Sweden, USA, Germany and Czech Republic is presented in paper. These techniques may be used for creation of similar technique in Lithuania with corrections connected with local geology. When determining radon risk mainly two parameters should be taken into account: radium content in soil (or radon content in soil air) which is associated with the type of soil and permeability of soil. The Lithuanian system of radon risk determination is not created yet because more detailed data on radon concentrations in soil air should be collected. Data from field measurements of radon concentrations in soil air and concentrations of naturally occurring radionuclides are presented. These measurements were carried out in some potentially important from the point of view of radon risk regions of Lithuania. Concentrations of Ra-226, Th-228 and K-40 in soil have been measured by gamma spectrometer GR-256 by Exploranium on the surface layer (up to 30 cm) of soil. Concentrations of radon in soil have been measured by MARKUS 10 in the depth of 70 cm. The measurements have been performed directly without sampling and sample preparation by digging the detector of Exploranium and pumping rod of MARKUS 10 in the investigated soil. The results indicate that there are some regions in Lithuania with radon concentrations in soil air exceeding 100 kBq/m3. Though radon risk depends on soil permeability these results show that these areas may be identified as areas of medium or even high radon risk. The system for classification of building sites in terms of indoor radon risk should be created in Lithuania in order to follow requirements of Lithuanian radiation protection standards and to keep below determined action levels of indoor radon- 400 Bq/m3 in existing buildings and 200 Bq/m3 in constructed ones. Results of indoor radon measurements are presented as well. The measurements have been performed in 400 randomly selected detached houses during heating season in two lowest permanently used rooms. Duration of one measurement exceeds 3 weeks. E-PERM electrets have been used for this type of measurements. The results show that the average concentration of indoor radon in Lithuania is 55 Bq/m3. In some cases these concentrations exceed the above-mentioned action levels and approach 2000 Bq/m. It shows that indoor radon problems exist in Lithuania as in many other countries. The average concentration of indoor radon in karst region is 125 Bq/m3. It shows that special attention should be paid to such regions because conditions for increased intake of radon to buildings may exist. Indoor radon is one of the main sources of exposure in Lithuania. In some cases it may be the essential source causing tens of milisieverts of annual effective dose. It shows that the problem of indoor radon is important in Lithuania.

scholarly journals Radon concentrations in multi-story buildings in Montenegro

2019 ◽  
Vol 34 (2) ◽  
pp. 165-174
Author(s):  
Perko Vukotic ◽  
Ranko Zekic ◽  
Nevenka Antovic ◽  
Tomislav Andjelic
Keyword(s):  
Radon Concentration ◽  
Building Materials ◽  
Indoor Radon ◽  
Small Contribution ◽  
Indoor Radon Concentration ◽  
Climate Conditions ◽  
Floor Level ◽  
Radon Activity ◽  
Activity Concentrations ◽  
Radon Concentrations

Change of radon concentrations in dwellings with floor level was studied in six multi-story buildings, in four towns of Montenegro with different climate conditions. The annual aver- age radon activity concentrations in 35 dwellings are found to be very low, mostly at a level of 20-30 Bqm?3. Absorbed gamma dose rates in these dwellings are in the range of 14-58 nGyh?1. The low radon concentrations are a consequence of a good tightness of the structures in contact with the ground and a small contribution of building materials to radon indoors. A clear general trend of changes in radon concentrations with floor level is not observed. In most of the dwellings on different floors in the multi-story building radon concentration varies very little, mostly within measurement error. A small decrease in radon concentration is noted between the two or three floors closest to the ground, but only in some of the buildings. Therefore, a decrease of indoor radon concentration with floor level cannot be considered as a general characteristic of multi-story buildings. Although the seasonal radon variations have not been in the focus of this study, it was found that the average radon activity concentrations in dwellings of the multi-story buildings are higher in warmer than in cooler half-year period, what is contrary to the general rule for homes in the world and in Montenegro as well.

scholarly journals Estimation of radon potential through measurement of uranium concentrations in granite geology

2019 ◽  
Vol 115 (7/8) ◽  
Author(s):  
Jacques Bezuidenhout
Keyword(s):  
Indoor Radon ◽  
Western Cape ◽  
High Concentration ◽  
Radon Exhalation ◽  
Bay Area ◽  
Physical Measurements ◽  
Radon Exhalation Rates ◽  
Radon Potential ◽  
The Hill ◽  
Radon Concentrations

The geology of an area can be used as a predictor for radon potential. Granite rock typically contains a high concentration of uranium and subsequent elevated emanation of radon gas. The geology of the western part of the Western Cape Province in South Africa is dominated by granite bedrock but very few studies on radon have been conducted in this area. Uranium concentrations were consequently measured on a large granite hill in the Saldanha Bay area of the Western Cape and a relationship between indoor radon and uranium concentrations was used to model radon potential on the outcrop. Results from granite rich environments in India were modelled in order to extract a relationship between indoor radon concentrations, radon exhalation rates and uranium concentrations. Radon exhalation rates greater than 0.35 Bq/m2h were predicted and estimated indoor radon concentrations in excess of 400 Bq/m3 were also predicted for the hill. The modelled results were compared with indoor radon measurements taken in the town of Paarl in the Western Cape, which sits on the same granite bedrock formation. The predicted radon potential correlated well with the physical measurements.

scholarly journals Estimation of Seasonal Correction Factors for Indoor Radon Concentrations in Korea

2018 ◽  
Vol 15 (10) ◽  
pp. 2251 ◽  
Author(s):  
Ji Park ◽  
Cheol Lee ◽  
Hyun Lee ◽  
Dae Kang
Keyword(s):  
Lung Cancer ◽  
Radon Concentration ◽  
Indoor Radon ◽  
Seasonal Adjustment ◽  
Correction Factors ◽  
Housing Type ◽  
Indoor Radon Concentration ◽  
Adjustment Factors ◽  
Radon Concentrations

Long-term exposure to high radon concentration exerts pathological effects and elicits changes in respiratory function, increasing an individual’s risk of developing lung cancer. In health risk assessment of indoor radon, consideration of long-term exposure thereto is necessary to identify a relationship between indoor radon exposure and lung cancer. However, measuring long-term indoor radon concentration can be difficult, and a statistical model for predicting mean annual indoor radon concentrations may be readily applicable. We investigated the predictability of mean annual radon concentrations using national data on indoor radon concentrations throughout the spring, summer, fall, and winter seasons in Korea. Indoor radon concentrations in Korea were highest in the winter and lowest in the summer. We derived seasonal correction and seasonal adjustment factors for each season based on the method proposed by previous study. However, these factors may not be readily applicable unless measured in a specific season. In this paper, we separate seasonal correction factors for each month of the year (new correction factors) based on correlations between indoor radon and meteorological factors according to housing type. To evaluate the correction factors, we assessed differences between estimated and measured mean annual radon concentrations. Roughly 97% of the estimated values were within ±40 Bq/m3 of actual measured values in detached houses, and roughly 85–87% of the estimated values were within ±40 Bq/m3 of the measured values in other residences. In most cases, the seasonal correction factors and the new correction factors had slightly better agreement than the seasonal adjustment factor. For predicting mean annual radon concentrations, the seasonal correction factors or seasonal adjustment factors can be of use when actual measurements of indoor radon concentrations for a specific season are available. Otherwise, the new correction factors may be more readily applicable.

Factors Affecting Indoor Radon Concentrations in the United Kingdom

1993 ◽  
Vol 64 (1) ◽  
pp. 2-12 ◽  
Author(s):  
J. A. Gunby ◽  
S. C. Darby ◽  
J. C. H. Miles ◽  
B. M. R. Green ◽  
D. R. Cox
Keyword(s):  
United Kingdom ◽  
Indoor Radon ◽  
Factors Affecting ◽  
The United Kingdom ◽  
Radon Concentrations
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