• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.72-79
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• 2000

In recent, occupational diseases in harmful working places become a social issue. It is the well-known fact that a respiration in polluted working places exert a serious effect on health of workers. Accordingly, the cutting off contaminants air originally is the best way to improve working environments. In these cases, ventilation systems should be essentially installed to dilute or exhaust the contaminated indoor air. In this study, we investigated the characteristics of ventilation system of the noxious gas in working indoor places with natural ventilation by using COMET. The numerical simulations were carried out the natural ventilation with two phase(air, dust). For turbulent flow, Reynolds stresses were closed by the standard $\kappa$-$\varepsilon$ model. The results are as follows ; 1) In the natural exhaust in the working place, the flows of the central region have a more rapid velocity vector than the right and left one. 2) Numerical results show that the distribution of contaminants concentration have greater influence on convection than the case of diffusion by government of velocity vectors. 3) To observe the velocity variation with distance, three location of distance are considered. As results, it shows that the velocity are 0.075(m/s) at y=5(m), 10(m) and mean concentration are raised 10.6% at y=5(m), 10(m). 4) We have presented the useful data for the adequate counterplan in the harmful working places by carrying out the various investigation of the natural ventilation.

• Particle and aerosol research
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• v.16 no.3
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• pp.65-72
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• 2020

In this study, the indoor fine dust concentration in an office of the Korea Knowledge Industry Center was measured for about 80 hours when the concentration of atmospheric PM_2.5 was very high. The effect of the operation of the air cleaner and the forced ventilation system on the indoor PM_2.5 was investigated, and the particle size distribution of the indoor and outdoor particles was analyzed. When forced ventilator and air purifiers were partially used, the indoor PM_2.5 concentrations were maintained between 27.7 ㎍/㎥ and 32.9 ㎍/㎥ when the atmospheric PM_2.5 was 127.7 ㎍/㎥ to 141.6 ㎍/㎥ during working hours. It is more effective to operate the air purifier without operating the forced ventilation system when the concentration of the PM_2.5 is high since the PM_2.5 penetrating the installed filter is continuously introduced indoor from the outside.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.748-753
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• 2008

In modern buildings, the air-tightness and insulation for energy saving resulted in degradation of Indoor Air Quality(IAQ). It has brought out new diseases such as New Building Syndrome(NBS) and Sick Building Syndrome(SBS) to the tenants of such buildings. As a result, researches on the Dynamic Breathing Building(DBB) are being undertaken to minimize energy loss as well as to improve IAQ. DBB is a state-of-the-art technology to build channels inside the wall so that air migrates between indoor and outdoor, which improves insulation performance and IAQ. This study attempts to evaluate the improvement of DBB employed in real buildings. As analyzing tools, IAQ improvement and particle degradation while were evaluated while the required indoor ventilation rate was satisfied. DBB were installed in the twin test cells at Korea Institute of Energy Research(KIER). From the test, IAQ was compared with outdoor air base on the concentration of particle matter(PM10). As a results, the concentration of particle dust (PM10) within the breathing walls was reduced by 80% at 0.7 ACH, 67% at 2 ACH, 63% at 3 ACH respectively. As ACH is higher, Dnamic Isulation(DI) and normal wall permit more PM10 particles being infiltrated.

• Journal of Korean Library and Information Science Society
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• v.50 no.4
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• pp.635-658
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• 2019

In this study, the harmful factors measured in S university's central library were divided into ① air harmful substance ② biological harmful factors ③ carbon monoxide, carbon dioxide, and nitrogen dioxide concentration, measured and analyzed compared to the relevant criteria. The analysis showed that the harmful substances in the air - fine dust, asbestos, volatile organic compounds and formaldehyde - were all lower than the relevant standards, and that biological harmful factors such as fungi in the air, gramophageal bacteria, and endotoxin were also found to have no particular problems. The concentration of carbon monoxide, carbon dioxide, and nitrogen dioxide in the air was also maintained without any unusual factors compared to the concentration in the ordinary atmosphere. However, the library is a multi-use facility that needs regular cleaning and ventilation to manage the environment.

• Journal of Environmental Health Sciences
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• v.47 no.4
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• pp.339-355
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• 2021

Background: Particulate matter (PM₁₀, PM_2.5) and black carbon contribute to poor air quality in urban areas, and can also affect indoor environments. Exposure to PM can be associated with respiratory and lung diseases. Objectives: This study investigated the indoor and outdoor concentration distribution patterns of PM₁₀, PM_2.5, and black carbon at an apartment building, a typical residential space in the metropolitan areas of South Korea, by season, day of the week (weekday vs. weekend), and time of the day. It aims to obtain foundational data for the effective management of pollutants and investigate the difference in pollution levels between indoor and outdoor environments. Methods: Indoor and outdoor concentrations of PM and black carbon were measured at an apartment building located in Namyangju, Gyeonggi-do Province, using dust sensors and an Aethalometer AE51 (AethLabs, San Francisco, CA, USA) over the course of a year from June 2020 to May 2021. The concentration distribution patterns were analyzed by season and time of day. Results: PM₁₀ and PM_2.5 concentrations in the outdoor environment were higher than those in the indoor environment, regardless of the season. By contrast, the indoor black carbon concentration was higher than that in the outdoor environment during summer and autumn. The concentrations of PM₁₀, PM_2.5 and black carbon were found to be higher on weekdays than during weekends, especially during rush hour, with concentrations of 25.92~56.58 ㎍/m³, 21.12~44.82 ㎍/m³, 0.63~3.40 ㎍/m³. Conclusions: The outdoor concentrations of PM₁₀, PM_2.5, and black carbon were higher during the weekdays, especially during rush hour, than during weekends. This study is expected to provide basic data for the health management of apartment occupants because it is measured over a period of more than one year.

• Journal of Environmental Health Sciences
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• v.49 no.4
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• pp.218-227
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• 2023

Background: Since 2019, the Ministry of Environment has implemented a seasonal fine dust management system from December to March, targeting high PM_2.5 levels with the aim of reducing PM_2.5 concentrations and protecting public health. The focus of improving the seasonal management system lies in the atmospheric PM_2.5 levels. Considering the primary goal of protecting public health, it is necessary to analyze the policy effects from an exposure perspective rather than a concentration-based approach. Objectives: This study aims to quantitatively assess the improvement of indoor PM_2.5 levels and the health impacts of the seasonal management system by comparing the periods before and during its implementation in residential environments. Methods: PM_2.5 concentrations within residential environments in a metropolitan area were measured using an optical particle counter (IAQ-C7, K-weather, Ltd, Korea) at one-minute intervals during the pre-implementation period (November 21~25, 2022) and during the implementation period (December 19~23, 2022). Based on the measured PM_2.5 concentrations, a quantitative evaluation of cancer and mortality risks was conducted according to age and gender. Results: The results of comparing indoor and outdoor PM_2.5 concentrations before and during the implementation of the seasonal management system showed a decrease of approximately 56.6% and 47.9%, respectively. Health risk assessments revealed that both the safety-limit-based and safety-target-based Hazard Quotients (HQ) exceeded the threshold of 0.1 for children under 19 years of age, both before and after the implementation. The mortality risk decreased by approximately 47.9% after the implementation, with children aged 0-9 showing the highest mortality risk at 0.9%. Conclusions: The findings of this study confirmed the positive health impacts of the seasonal management system across all age groups, particularly children under 19 who are more vulnerable to fine dust exposure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.7
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• pp.83-91
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• 2011

Even if smoke, fumes, mist or dust particles are removed by electrostatic precipitators (ESPs), the occurrence of ozone, which is harmful to human body, has to be severely restricted in the indoor environments of hospitals, offices, and workshops. Therefore, the two-stage ESP generating positive corona at the ionizer is typically used because it creates less ozone than the two-stage ESP generating negative corona at the ionizer. In order to predict the collection performance and the optimal design of the two-stage ESP applied to positive high-voltage, particle concentration is experimentally investigated in this paper. In addition, particle motion within the collector section is also numerically analyzed. The positive corona discharge current of the ionizer is found to be affected by the applied voltage in the collector section but less so by the particle concentration. Particle concentration shows a minimum near the high voltage electrode of the collector section. The minimum value of the collection efficiency is almost proportional to gas velocity. When the collector length decreases, the minimum value of the collection efficiency increases. Charged particles entering the collector region are linearly deflected towards the grounded plate by an electric field. From the above experimental and numerical results, two empirical equations on the concentration ratio and the collection efficiency are derived, and are in good agreement with the experimental data.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.409-410
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• 2018

Background: Asthma is one of the most common chronic diseases and can be affected by environmental factors. It has been reported that exposure to indoor environmental factors can cause infantile asthma during infancy and childhood, but the previous studies are not yet clear. Climate change has recently been shown to increase indoor mold. Exposure to fungi is known to be directly related to the development of aggravation. Methods: This study was conducted from July 20, 2016 to September 30, 2016. The study was conducted on 90 household with children under the age of 7 who attend atopy school. The questionnaire surveyed allergic symptoms, social and demographic characteristics, and environmental characteristics. Environmentally hazardous substances were measured such as temperature, humidity, fine dust, volatile organic compounds, formaldehyde, bacteria, fungus, house dust mite, endotoxin. Results: According to the survey results, 9 patients (10%) were treated with asthma, 6 (6.7%) were asthmatic patients during the past 12 months, and 4 patients (4.4%) were asthmatic patients during the past 12 months. There were statistically significant differences in the direct effect of smokers in the family (P=0.0328). High-filter vacuum cleaners collected $0.4222CFU/m^3$ in subjects without asthma, and $0.2222CFU/m^3$ in subjects with asthma. In addition, various results confirmed that asthma exacerbated by mold exposure. Conclusions: The results of this study suggest that exposure to fungal by infants and toddlers may play an important role in the development of asthma. In this study, we investigated the relationship between asthma and fungal concentration.

• Asian Journal of Atmospheric Environment
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• v.4 no.3
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• pp.115-140
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• 2010

Great concerns about atmospheric aerosols are attributed to their multiple roles to atmospheric processes. For example, atmospheric aerosols influence global climate, directly by scattering or absorbing solar radiations and indirectly by serving as cloud condensation nuclei. They also have a significant impact on human health and visibility. Many of these effects depend on the size and composition of atmospheric aerosols, and thus detailed information on the physicochemical properties and the distribution of airborne particles is critical to accurately predict their impact on the Earth's climate as well as human health. A single particle analysis technique, named low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA) that can determine the concentration of low-Z elements such as carbon, nitrogen and oxygen in a microscopic volume has been developed. The capability of quantitative analysis of low-Z elements in individual particle allows the characterization of especially important atmospheric particles such as sulfates, nitrates, ammonium, and carbonaceous particles. Furthermore, the diversity and the complicated heterogeneity of atmospheric particles in chemical compositions can be investigated in detail. In this review, the development and methodology of low-Z particle EPMA for the analysis of atmospheric aerosols are introduced. Also, its typical applications for the characterization of various atmospheric particles, i.e., on the chemical compositions, morphologies, the size segregated distributions, and the origins of Asian dust, urban aerosols, indoor aerosols in underground subway station, and Arctic aerosols, are illustrated.

• Journal of Conservation Science
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• v.38 no.1
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• pp.64-71
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• 2022

Many investigations have been conducted on the biological damage and environmental conditions necessary to preserve the Janggyeong Panjeon and Daejanggyeongpan (woodblocks). We performed a survey on the concentration and diversity of airborne fungi in the Janggyeong Panjeon and compared them with the results of a survey from 2012. The temperature of the Beopbojeon building was slightly lower, while the relative humidity was higher than those found at the Sudarajang building. The concentration of airborne fungi in the Beopbojeon was 1.44-fold that of the Sudarajang. It was confirmed that the concentration and diversity of airborne fungi in the Janggyeong Panjeon differed depending on the sampling site. In total, 23 fungal genera were identified from the air samples, and 11 fungal and 1 bacterial genera were identified from the surface of the woodblocks. Among these, only five types of fungi were commonly distributed in the indoor air and surface of the Daejanggyeongpan; however, 58.3% of the fungi identified on the surface of the woodblocks were not observed in the in the air samples. The surface-dwelling fungi may accumulate dust to form microbial communities over time.