• 한국대기환경학회지
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• 제25권1호
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• pp.38-45
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• 2009

Since the seventies and the oil crisis, energy-saving measures have led to a reduction in the ventilation of room. The use of synthetic materials which emit various chemical substances had led to an increase in the concentration of indoor pollutants. "Sick building syndrome (SBS)" and "Sick house syndrome (SHS)" are worldwide problems. Also, the number of complaints about indoor air pollution caused by VOCs (Volatile organic compound) and HCHO (Formaldehyde) has increased. It is important that evaluating and understanding emission of indoor air pollutant from building materials. The object of this study was to evaluate emission test method for flooring such as wood based flooring, carpet tile, rubber tile, PVC sheet and tile, and to determine emission of TVOC and form-aldehyde. The quantity of TVOC and carbonyl compounds emission were sampled and measured by Tenax TA and gas chromatography/mass spectrometry (GC/MSD), 2,4-DNPH cartrige with ozone scrubber and high performance liquid from flooring. The TVOC concentration emitted from carpet tile was ($7.419\;mg/m^2 h$) the highest among 5 groups of test materials. In wood based flooring and PVC tile, the emitted concentration of toluene was high. And the dodecane emission was highest in carpet. The concentration of TVOC decreased by an increase in emission test period. After 7 days, the concentration of TVOC from floorings were about 50% below of the concentration at the first day. TVOC emission from wood based flooring, carpet tile, rubber tile, PVC sheet and tile were decreased in 28 days and remained steady after about 15 days. The concentration of formaldehyde emission from floorings showed extremely low.

• 한국환경과학회지
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• 제12권9호
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• pp.967-976
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• 2003

Volatile organic compounds (VOCs) are present in essentially all natural and synthetic materials from petrol to flowers. In this study, indoor and outdoor VOCs concentrations of houses, offices and internet-cafes were measured and compared simultaneously with personal exposures of each 50 participants in Asan and Seoul, respectively. Also, factors that influence personal VOCs exposure were statistically analyzed using questionnaires in relation to house characteristics, time activities, and health effects. All VOCs concentrations were measured by OVM passive samplers (3M) and analyzed with GC/MS. Target pollutants among VOCs were Toluene, o-Xylene, m/p-Xylene, Ethylbenzene, MIBK, n-Octane, Styrene, Trichloroethylene, and 1,2-Dichlorobenzene. Indoor and outdoor VOCs concentrations measured in Seoul were significantly higher than those in Asan except Ethylbenzene. Residential indoor/outdoor (I/O) ratios for all target compounds ranged from 0.94 to 1.51 and I/O ratios of Asan were a little higher than those of Seoul. Relationship between personal VOCs exposure, and indoor and outdoor VOCs concentrations suggested that time-activity pattern could affect the high exposure to air pollutant. Factors that influence indoor VOCs level and personal exposure with regard to house characteristics in houses were building age, inside smoking and house type. In addition insecticide and cosmetics interestingly affected the VOCs personal exposure. Higher exposure to VOCs might be caused to be exciting increase and memory reduction, considering the relationship between measured VOCs concentrations and questionnaire (p<0.05).

• 전기학회논문지
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• 제56권5호
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• pp.921-925
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• 2007

Gas removal characteristics of an air clean system, consisted of a filter and a nonthermal discharge plasma reactor with a magnetic field, have been investigated with emphasis on the enhancing gas removal efficiency of the applied magnetic field. It is found that the magnetic field influenced significantly to the corona discharge characteristics, decreasing the corona onset voltage and increasing the corona current. As a result, the proposed air clean system with the magnetic field showed the higher removal efficiency of the gas (e.g., trimethlyamine) than that of without the magnetic field. This would be because the magnetic field applied to the discharge plasma reactor of the air clean system can elevate the corona characteristics, and activate the generation of ozone, thus the removal efficiency of the gas was concurrently enhanced. This reveals that the proposed air clean system with the magnetic field could be used as an effective means of removal an indoor pollutant gas.

• 환경위생공학
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• 제17권2호
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• pp.85-91
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• 2002

Workers who work at indoor and outdoor environment near busy road are suspected to be exposed to high-elevated air pollutant levels during working hours. This study evaluated the working-time nitrogen dioxide ($NO_2$) exposure for workers (repairmen and polishers) of shoe-stalls. Since shoe-stalls have particularly been located near busy road in Korea, workers might be high exposure to $NO_2$ from traffic exhaust as well as indoor sources of shoe-stall such as portable gas range (butane gas) during working hours. In this study, we measured the indoor and outdoor $NO_2$ concentrations of shoe-stalls. Simultaneously, outdoor $NO_2$ concentrations of building through sidewalk from shoe-stall were measured. High $NO_2$ exposure for workers of shoe-stalls was considered to be inflow of outdoor source of exhausted emission from vehicles and indoor source from usage of gas range to polish the shoe. Indoor/outdoor $NO_2$ concentration ratio ($0.94{\pm}0.22$) in Seoul was higher than that ($1.06{\pm}0.34$) in Asan, because ambient $NO_2$ level was high in Seoul and usage of gas range was prevalent in Asan. According to $NO_2$ concentrations by distance from roadside to building through sidewalk, $NO_2$ concentrations showed the decreased trend with distance. The results of this study can be utilized by municipal authorities in urban planning for evaluating effects of future traffic planning and land use.

• 한국환경보건학회지
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• 제36권6호
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• pp.472-479
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• 2010

The purpose of this study was to investigate the concentration of indoor air pollutants at 63 elementary schools, 41 middle schools and 51 high schools in Ulsan from the beginning of May to the end of December, 2008. To assess the indoor air quality of the various classrooms, the 8 indoor air pollutants such as $CO_2$, CO, $NO_2$, $O_3$, $PM_{10}$, TVOCs, HCHO and TBC were measured and analyzed. The mean concentrations of $PM_{10}$ and TBC in the elementary schools were significantly higher than those of middle and high schools (p < 0.01). For the HCHO, the multi-use practice rooms showed an average 1.5 times higher than general classrooms. In schools located in urban areas, the concentrations of CO, $O_3$, $PM_{10}$, HCHO and TBC were lower than in the vicinity of industrial complexes. The exceeding rate of the school air quality maintenance limits in the 6 air pollutants by law were 6.7%, 3.5%, 1.7%, 18.2%, 13.0% and 18.4% for $CO_2$, $NO_2$, $O_3$, $PM_{10}$, HCHO and TBC, respectively. Based on these results $PM_{10}$ and TBC have to be in the order of priority of need to improve the classroom air quality in elementary school of Ulsan.

• 한국대기환경학회지
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• 제16권6호
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• pp.625-631
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• 2000

Practical devices for measuring personal exposure to nitrogen dioxide(NO$_2$) have been made for epidemiological studies of the health effects of air pollution Standard methods for NO$_2$ measurement such as the chemiluminescent method and Saltzman method are not suitable for personal exposure because they are heavy, large and complicated to operate. In this study, a passive monitor was tested for the measurements of indoor and outdoor NO$_2$ level. Through a comparative analysis of data sets obtained by on-site chemiluminescence system, we assessed the accuracy and precision of NO$_2$ passive monitors. We also examined the possibility of passive monitor in the study of indoor, outdoor and personal NO$_2$ exposure. The accuracy and precision of NO$_2$ passive monitor were analyzed assuming measurements of on-site chemiluminescence system is reference value and using duplicated measure- ments, respectively. From these analysis the NO$_2$ passive monitor was useful for measuring indoor, outdoor and personal exposure. And NO$_2$ level from on-site chemiluminescence systems could not properly represent the personal NO$_2$ exposure as well as indoor and outdoor level of ones house. Personal exposures were correlated more strongly with indoor NO$_2$ concentrations than with outdoor NO$_2$ concentrations. Since activity pattern of each person is different, it was considered that personal daily behavior and life-style might prevent the air pollutant exposure.

• 한국환경보건학회지
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• 제46권6호
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• pp.685-693
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• 2020

Objectives: Recent data indicate that sensitization to mold contributes to the severity and persistence of asthma. The aim of this study was to investigate relationships between indoor mold concentrations and pulmonary function parameters in asthmatic children with mold sensitization. Methods: Asthmatic subjects who had a positive result in skin-prick testing to more than one mold allergen, such as Alternaria, Aspergillus, or Penicillium, were enrolled. Their pulmonary function and methacholine challenge test results were collected. Measurements of blood eosinophil, serum IgE, and fractional exhaled nitric oxide (FeNO) were taken. Indoor levels of VOC, CO2, PM10 and PM2.5 in each subject's house were measured. We counted mold and bacteria colonies from the subjects' house air samples. Results: The mean levels of FEV1, FVC, FEV1/FVC, and FEF25-75 were 82.8±19.7, 87.3±17.9, 85.8±8.3, and 82.3±28.9%, respectively. The mean FeNO level was 19.8±11.2 ppb and the geometric mean (range of one SD) of methacholine PC20 was 3.99 mg/mL (0.67-23.74 mg/mL). The average indoor air pollutant levels were below the recommended levels set by the Ministry of Environment for multiplex buildings. Indoor mold levels showed a significant inverse correlation with methacholine PC20, but not with the baseline pulmonary function parameters. Conclusion: Indoor mold concentrations are a risk factor for increased bronchial hyperresponsiveness among asthmatic children with mold sensitization. Targeted environmental intervention should be considered for selected asthmatic children with mold sensitization for avoiding severe airway hyperresponsiveness.

• 한국환경보건학회지
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• 제30권5호
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• pp.353-357
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• 2004

The purpose of this research is to characterize formaldehyde as trace toxic air pollutant in the underground spaces in Gyungnam province. Air samples of formaldehyde were taken in the three underground spaces for ten months from April 2003 to January 2004. The IAQ(Indoor Air Quality) of underground spaces were controled using central ventilation(supply/exhaust) system. The levels of GM of airborne formaldehyde concentrations in three sampling spaces were well below applicable standards, Korean Ministry of Environment, 0.1 ppm. However, some sample of airborne formaldehyde concentrations in underground spaces 'B' and 'C' were in excess of standard, due to the commercial products in shop, structural material, and the climate having high humidity and temperature. There are statistical differences in levels of formaldehyde by sampling spaces (p=0.086).

• KIEAE Journal
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• 제7권4호
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• pp.51-56
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• 2007

This study focuses on developing natural ventilation system which is able to satisfy the good indoor air quality and air speed. The natural ventilation system developed in this study is for double window façade and it has two operation modes for summer and winter. Operational sections of the devices have been analyzed by CFD simulation to calculate discharge coefficients of openings and estimated indoor air speed. For the analysis of the appropriate installation area ratio for each room and the optimum installation area, TRNFLOW simulation has been used. As the results, we could see that the natural ventilation system can provide the similar pollutant removal performance to 0.7 ACH of mechanical ventilation with appropriate installation area and installation area ratio.

• 환경위생공학
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• 제20권4호통권58호
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• pp.51-58
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• 2005

Photocatalytic degradation using $TiO_2$ Particles suspended in a reactor was experimentally performed to degrade the formaldehyde of indoor pollutants. Exponential increase of degradation appears to prove light availability due to the scattering of W light by particles themselves. Comparative removal studies of formaldehyde were done in both cases of dipping and spraying immobilized techniques of $TiO_2$ Particles suspended in solution. Experiments were performed under several different experimental conditions such as initial concentration of formaldehyde, UV intensity and concentration of photocatalysts. Optimal conditions to degrade formaldehyde were obtained under the conditions of $30\;mg/cm^2$ concentration of catalyst and UV intensity of 30 Watt at the distance of 30 cm using immobilized technique by dipping coating.