• Asian-Australasian Journal of Animal Sciences
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• v.32 no.5
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• pp.742-747
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• 2019

Objective: A concentration of airborne bacteria generated from swine houses is recognized to be relatively higher than other work places and it is essential to optimally manage it to prevent farmers' respiratory diseases. This study was conducted to assess the distribution characteristics of airborne bacteria in swine houses located at South Korea. Methods: A total 27 pig buildings of the enclosed type operated with mechanical ventilation system by a side wall fan and deep-pit manure system with slats were surveyed. Air samples were collected at 1.0 m above the middle floor in pig housing room. A six-stage viable particulate cascade impactor was used to identify the distribution of the sizes of particles in diameter. Results: Seasonal mean levels of airborne bacteria in the housing rooms of gestation/farrowing pigs, nursery pigs and growing/fattening pigs were 3,428(${\pm}1,244$) colony forming unit $(cfu)/m^3$, $8,325({\pm}3,209)cfu/m$, and $13,254({\pm}6,108)cfu/m^3$ for spring; $9,824({\pm}2,157)cfu/m^3$, $18,254({\pm}5,166)cfu/m^3$, and $24,088({\pm}9,274)cfu/m^3$ for summer; $1,707({\pm}957)cfu/m^3$, $4,258({\pm}1,438)cfu/m^3$, and $8,254({\pm}2,416)cfu/m^3$ for autumn; and $2,322({\pm}1,352)cfu/m^3$, $6,124({\pm}1,527)cfu/m^3$ and $12,470({\pm}4,869)cfu/m^3$ for winter, respectively. Conclusion: Concentrations of airborne bacteria according to pig housing type were highest in growing/fattening housing room followed by nursery housing room and gestation/farrowing housing room. In terms of seasonal aspect, the pig building showed the highest levels of airborne bacteria in summer followed by spring, winter and autumn. The respirable airborne bacteria which are ranged between 0.6 and $4.7{\mu}m$ accounted for approximately 60% compared to total airborne bacteria regardless of pig housing type.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.2
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• pp.176-184
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• 2019

Objective: This study aims to characterize airborne radon and thoron levels ($Bq/m^3$) generated from working environments in three subway stations in Seoul. Method: A radon and thoron detector (EQF3220) was used to monitor real-time airborne radon and thoron levels ($Bq/m^3$) and their daughters ($Bq/m^3$) every two hours. They were monitored not only in the driver's cabin of seven circulation lines, but also three offices, platforms, and water pump reservoirs in the three stations. Results: The average levels of radon and thoron were $67.9Bq/m^3$ (range; $7.2-619.4Bq/m^3$) and $44.4Bq/m^3$ (range; $4.3-819.2Bq/m^3$), respectively. Notably, higher than legal airborne radon levels ($600Bq/m^3$) were frequently monitored in the driver's cabin of seven circulation lines. Airborne radon levels monitored in the platforms and administrative offices were found to be over $100Bq/m^3$. The average equilibrium factors (F) were 0.12 and 0.06, respectively. The percentages detected were found to be 84.9 for radon and 72.4 for thoron, respectively. Conclusions: Significant airborne radon and thoron levels were frequently found to be generated in subway facilities including water reservoirs, platforms and driver's cabins. Further study is necessary to thoroughly investigate airborne radon and thoron in all subway stations and to devise proper measures.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.4
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• pp.87-92
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• 2019

This paper describes the pattern analysis for data of the factory energy consumption by using machine learning method. While usual statistical methods or approaches require specific equations to represent the physical characteristics of the plant, machine learning based approach uses historical data and calculate the result effectively. Although rule-based approach calculates energy usage with the physical equations, it is hard to identify the exact equations that represent the factory's characteristics and hidden variables affecting the results. Whereas the machine learning approach is relatively useful to find the relations quickly between the data. The factory has several components directly affecting to the electricity consumption which are machines, light, computers and indoor systems like HVAC (heating, ventilation and air conditioning). The energy loads from those components are generated in real-time and these data can be shown in time-series. The various sensors were installed in the factory to construct the database by collecting the energy usage data from the components. After preliminary statistical analysis for data mining, time-series clustering techniques are applied to extract the energy load pattern. This research can attributes to develop Factory Energy Management System (FEMS).

• Journal of the Korean Society of Safety
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• v.36 no.1
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• pp.86-94
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• 2021

Lecture rooms are crowded with many attendees. Moreover, they rely significantly on the natural ventilation through windows for removing and controlling indoor contaminants such as CO₂. With the aim of broadening the understanding of the characteristics of natural ventilation phenomena in lecture rooms, the average individual CO₂ release rates of attendees were measured during the course of a lecture and compared with previously reported CO₂ release rates. In addition, the effects of natural ventilation through windows on the time-variant CO₂ concentrations in the center of the lecture room were measured and analyzed. Moreover, details about the overall and regional CO₂ concentrations, as well as the air flows in the lecture room, were simulated and analyzed with computational fluid dynamics software, Fluent 2020 R2. It was found that the average individual CO₂ release rates were slightly slower than previously reported rates. The local CO₂ concentrations in the lecture room for regions with a high density of attendees increased over a short period of time, although the natural ventilation was already started by opening the windows. The overall CO₂ concentration in the lecture room rapidly decreased in the early stage of ventilation, but declined very slowly after a longer period of ventilation time. Therefore, in order to enhance the efficiency of a lecture room's natural ventilation, it is recommended to homogeneously distribute the attendees in the lecture room, and to frequently open the windows for short periods of time.

• Journal of Urban Science
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• v.10 no.1
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• pp.29-37
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• 2021

The number of old buildings older than 30 years in Korea continues to increase from 29.9% in 2005 to 38.8% in 2020. Considering the growing urban regeneration projects, urban maintenance projects, the suppression of urban expansion, and the lack of idle land in the city, the dismantling of old buildings is expected to increase further in the future. As major accidents at building dismantling sites continue to occur, related agencies are also strengthening safety management of building dismantling works. While physical safety management such as collapse and fall is strengthened, there is a relative lack of interest in the health of workers at dismantling sites due to environmental hazards. Since relevant laws stipulate that construction waste should be separated and discharged, old buildings need to be considered for environmental hazards such as fine dust, floating bacteria, and floating molds when dismantling. In this study, we intend to find important safety management elements in the management of building dismantling sites, measure environmental factors harmful to dismantling workers, and present basic data for the management of dismantling sites in the future. "Safety management" was the highest priority, followed by "dust," "vibration," "noise," "bacteria," and "smell." The perception of the importance of "physical damage prevention" with workers working on dismantling and managers managing the site came out similar, but the perception of "work efficiency" and "health disorder prevention" through environmental hazard management showed different priorities. In the process of dismantling, floating bacteria and floating mold were collected, cultured, and measured the concentration in the indoor air. The measurement was measured by dividing it into pre-dismantling and during dismantling.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.505-512
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• 2021

Background: The occurrence of environmental disease is known to be associated with chronic exposure to toxic chemicals, including waterborne contaminants, air/indoor pollutants, asbestos, ingredients in humidifier disinfectants, etc. Objectives: In this study, we reviewed toxicological studies related to environmental disease as defined by the Environmental Health Act in Korea and toxic chemicals. We also suggested a direction for future toxicological research necessary for the prevention and management of environmental disease. Methods: Trends in previous studies related to environmental disease were investigated through PubMed and Web of Science. A detailed review was provided on toxicological studies related to the humidifier disinfectants. We identified adverse outcome pathways (AOPs) that can be linked to the induction of environmental diseases, and proposed a chemical screening system that uses AOP, chemical toxicity big data, and deep learning models to select chemicals that induce environmental disease. Results: Research on chemical toxicity is increasing every year, but there is a limitation to revealing a clear causal relationship between exposure to chemicals and the occurrence of environmental disease. It is necessary to develop various exposure- and effect-biomarkers related to disease occurrence and to conduct toxicokinetic studies. A novel chemical screening system that uses AOP and chemical toxicity big data could be useful for selecting chemicals that cause environmental diseases. Conclusions: From a toxicological point of view, developing AOP related to environmental diseases and a deep learning-based chemical screening system will contribute to the prevention of environmental diseases in advance.

• Animal Bioscience
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• v.35 no.2
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• pp.308-316
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• 2022

Objective: This study was conducted to determine reduction of various odorous materials from a swine farm equipped with a continuous pit recirculation system (CPRS) with aerobically treated liquid manure. Methods: The CPRS is used in swine farms in South Korea, primarily to improve air quality in pig houses. In this study, CPRS consists of a manure aerobic treatment system and a fit recirculation system; the solid fraction is separated and composted, whereas the aerobically treated liquid fraction (290.0%±21.0% per day of total stored swine slurry) is continuously returned to the pit. Four confinement pig barns in three piggery farms were used; two were equipped with CPRS and the other two operated a slurry pit under the slatted floor. Results: All chemical contents of slurry pit manure in the control were greater than those of slurry pit manure in the CRPS treatment (p<0.05). Electrical conductivity and pH contents did not differ among treatments. The biological oxygen demand of the slurry pit treatment was greater than that of the other treatments (p<0.05). Total nitrogen, total phosphorus, and ammonia nitrogen contents of the slurry pit treatment were greater than those of other treatments (p<0.05). Odor intensity of the CPRS treatment was lower than that of the control at indoor, exhaust, and outside sampling points (p<0.05). The temperature and carbon dioxide of the CPRS treatment in the pig barn was significantly lower than those of control (p<0.05). All measured odorous material contents of the CPRS group were significantly lower than those of the control group (p<0.05). Conclusion: The CPRS application in pig farms is considered a good option as it continuously reduces the organic load of animal manure and lowers the average odorant concentration below the threshold of detecting odorous materials.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.1-14
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• 2022

This study aims to identify topics in newspaper articles related to fine particle matter and to investigate the characteristics and time series trend of each topic. Related national newspaper articles during 1990 and 2021 were collected from Bigkinds. A total of 18 topics have been discovered using LDA, and 11 clusters deduced from clustering. Hot topics include related products/residence, overseas cause(China), power plant as a domestic cause, nationwide emergency reduction measures, international cooperation, political issues, current situation & countermeasure in other countries, and consumption patterns. Cold topics include the concentration standard and indoor air quality improvement. These findings would be useful in inferring the political direction and strategies. In particular, the consumer protection policy should be expanded as the related market is growing. It will also be necessary to pursue policies that will promote public safety and health, and that will enhance public consensus and international cooperation.

• Journal of Sensor Science and Technology
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• v.30 no.4
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• pp.191-195
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• 2021

Pure ZnFe₂O₄ and Fe₂O₃-ZnFe₂O₄ hetero-composite spheres were prepared by ultrasonic spray pyrolysis of a solution containing Zn- and Fe-nitrates. Additionally, the sensing characteristics of these spheres in the presence of 5 ppm ethanol, benzene, p-xylene, toluene, and CO (within the temperature range of 275-350 ℃) were investigated. The Fe₂O₃-ZnFe₂O₄ hetero-composite sensor with a cation ratio of [Zn]:[Fe]=1:3 exhibited a high response (resistance ratio = 140.2) and selectivity (response to p-xylene/response to ethanol = 3.4) to 5 ppm p-xylene at 300 ℃, whereas the pure ZnFe₂O₄ sensor showed a comparatively lower gas response and selectivity. The reasons for the superior response and selectivity to p-xylene in Fe₂O₃-ZnFe₂O₄ hetero-composite sensor were discussed in relation to the electronic sensitization due to charge transfer at Fe₂O₃-ZnFe₂O₄ interface and Fe₂O₃-induced catalytic promotion of gas sensing reaction. The sensor can be used to monitor harmful volatile organic compounds and indoor air pollutants.

• Journal of Preventive Medicine and Public Health
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• v.55 no.3
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• pp.273-279
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• 2022

Objectives: The aim of this study was to present the baseline results of a pilot project conducted to evaluate the effectiveness of lung cancer screening using low-dose chest computed tomography (CT) in regions with excessive radon levels in the Republic of Kazakhstan. Methods: In total, 3671 participants were screened by low-dose chest CT. Current, former, and never-smokers who resided in regions with elevated levels of radon in drinking water sources and indoor air, aged between 40 and 75 with no history of any cancer, and weighing less than 140 kg were included in the study. All lung nodules were categorized according to the American College of Radiology Lung Imaging Reporting and Data System (Lung-RADS 1.0). Results: Overall, 614 (16.7%) participants had positive baseline CT findings (Lung-RADS categories 3 and 4). Seventy-four cancers were detected, yielding an overall cancer detection rate of 2.0%, with 10.8% (8/74) stage I and a predominance of stage III (59.4%; 44/74). Women never-smokers and men current smokers had the highest cancer detection rates, at 2.9% (12/412) and 6.1% (12/196), respectively. Compared to never-smokers, higher odds ratios (ORs) of lung cancer detection were found in smokers (OR,2.48; 95% confidence interval [CI], 1.52 to 4.05, p<0.001) and former smokers (OR, 2.32; 95% CI, 1.06 to 5.06, p=0.003). The most common histologic type of cancer was adenocarcinoma (58.1%). Conclusions: Implementation of low-dose CT screening for lung cancer in regions with elevated radon levels is an effective method for both smokers and never-smokers.