• Journal of Environmental Science International
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• v.12 no.12
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• pp.1235-1243
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• 2003

Under controlled conditions in an environmental chamber, 24 experiments were performed to compare the ability of a Variable-Air-Volume/Bypass Filtration System(VAV/BPFS) to remove indoor pollutants and to conserve energy with the ability of conventional Variable Air Volume(VAV) system. The specific conclusions of this paper were; first, the VAV/BPFS was more efficient than the VAV system in removing particulate matter, TVOC, and target VOCs. The total effective removal rate of PM for the VAV/BPFS was two times as high as that of the VAV system. The total effective removal rate of TVOC for the VAV/BPFS was 20 percent higher than that of the VAV system. Also each target VOC concentration was reduced by using the VAV/BPFS. Second, clean air delivery rate was increased by using VAV/BPFS due to additional filtration rate. Otherwise, the VAV/BPFS decreased outdoor supply air rate above 25 percent relative to the rate of VAV system. Third, total energy consumption by the VAV/BPFS was lower than that of the VAV system during the period with indoor thermal load, occupied time. The energy saving of the VAV/BPFS ranged from 11 to 16 percent. The VAV/BPFS improves indoor air quality more efficiently than the VAV system, and it reduced energy consumption. Retrofitting the VAV system with the VAV/BPFS was easy The use of VAV/BPFS is, therefore, recommended far buildings with VAV system as well as for buildings at designing stage.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1180-1185
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• 2006

Modern people spend most of time at indoor space, such as office or classroom. Especially, occupants are exposed to the airtight indoor air quality (IAQ) for a long time, At present, many studies on the air-conditioning systems are more focused on the individual thermal comfort than the thermal efficiency due to increase of the concern of health. There are several factors which are influenced thermal comfort, such as temperature, humidity, convection and air movement, etc. Also, the individual factor, such as age, gender, Physical constitution and habit, should be considered. The 4-way cassette type air conditioner is known to bring out better performance about thermal comfort than the traditional one. This study is performed on the higher ceiling environment than the common buildings or classrooms. Also, this study analyzed on the Indoor thermal comfort by diffusing direction of 4-way cassette air conditioner with various discharge angles, $45^{\circ},\;50^{\circ},\;55^{\circ}$ and $60^{\circ}$. Using a commercial code, FLUENT, three-dimensional transient air thermal flow fields are calculated with appropriate wall boundary conditions and standard $k-{\epsilon}$ turbulence model. Results of velocity and temperature distributions are graphically depicted with various discharge angles.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.259-263
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• 2004

This study was performed to investigate airborne formaldehyde concentration in preschool facilities. Arithmetic mean of indoor formaldehyde concentration in urban area was 34.9 ppb(Geometric mean 24.4 ppb) whereas outdoor concentration was 21.5 ppb(GM 11.9 ppb). In rural area, formaldehyde concentrations were 36.4 ppb(GM 28.7 ppb), 4.1 ppb(GM 4.1 ppb), respectively. There is no statistical significance between the formaldehyde concentrations of urban classrooms and those of rural area. We verified that the distribution of airborne formaldehyde concentration was log-normal characteristic using Shapiro and Wilk test. The 6.7% of urban indoor samples was exceeded the domestic standard limit of indoor air quality. From our study and other study, we concluded that the major emission sources of formaldehyde in preschool facilities was in indoor rather than outdoor.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1652-1655
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• 2008

Indoor air quality (IAQ) of subway becomes a key issue as the IAQ guidelines for public transportation published. There are two major sources regarding IAQ of subway; One is the sources coming from outdoor air and the other is sources of inside. Particulate matters smaller than 10 micrometer (PM10) and carbon dioxide ($CO_2$) are recognized as the one of the most severe pollutants in Korea. The source of PM10 is mainly coming from outdoor air, however, the source of $CO_2$ is coming from passengers exhaust. According to the guidelines, the level of $CO_2$ should be lower than 2500ppm for normal operating time and lower than 3500ppm for rush hour. In order to satisfy these guidelines, the volume of mechanical ventilation should be increase which consumes extra energy for heating or cooling. Therefore, the optimum volume of mechanical ventilation should be calculated for energy saving. In this study, we measured the natural ventilation rate by door-opening which can reduce the load of mechanical ventilation. The $CO_2$ generator and sensors were used to measure the change of $CO_2$ by periodic door-opening of subway.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.7
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• pp.402-408
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• 2009

In this paper, the effects of ventilation and humidification on thermal comfort and indoor air quality(IAQ) were evaluated in a classroom when a heat pump system was operated in winter. Thermal comfort parameters, such as temperature, relative humidity, globe temperature and air velocity, were measured at 9 points in the classroom. The concentration of $CO_2$ and total suspended particles(TSP) in the classroom were measured in order to analyze IAQ. Temperature distribution in the classroom was decreased by $2{\sim}5^{\circ}C$ when the ventilation system and the humidifier were operated. When the relative humidity was adjusted to 60% by operating the humidifier and the ventilation system, the predicted mean vote(PMV) in the classroom was within the comfortable range of $-0.5{\sim}0.5$. When the ventilation system was operated, the average concentration of $CO_2$ and TSP were decreased by 645 ppm and 0.17 $mg/m^3$, respectively. This paper suggests the humidification and ventilation conditions to maintain the comfortable environment in the school classroom in winter experimentally.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.304-306
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• 2000

오늘날 경제적 생활 환경의 개선으로 인하여 현대인의 생활에 많은 변화를 가져오고 있다 제한된 공간에서 인간 활동은 지하생활공간이라는 새로운 활동영역을 창출하였고, 이에 따라 실내에서의 거주 시간은 더욱 증가하고 있다. 지하생활공간이라는 용어가 일반인들에게는 다소 생소하게 받아들여질 수 있지만 여기서 말하는 지하생활공간이라 함은 불특정 다수인이 이용하는 지하철, 지하상가, 지하주차장, 지하 보·차도, 지하터널 등을 말하며 개인의 생활 양식에 따라 단시간 이용하거나 또는 생활터전으로 장시간 거주할 수 있는 공간이라고 할 수 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.177-178
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• 2002

최근 국내의 생활 문화가 점차 서구화되어 가면서 카페트를 사용하는 장소가 증가하고 있으며, 실내 소음 방지, 보온, 분위기 조성 등을 위한 목적으로 카페트의 사용범위는 점차 넓어지고 있다. 하지만 이러한 카페트는 실내 VOCs 방출원 중의 하나로 보고되고 있으며, 여기서 방출된 VOCs는 실내 공기질(Indoor Air Quality: 이하 IAQ라 칭함)저하를 유발하는 요소 중의 하나이다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.177-178
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• 2002

최근 삶의 질이 향상은 건강에 대한 환경적 관심으로 연계되고 있다. 특히 현대인의 생활양식과 근무양식이 1일 실내 생활시간이 전체의 80%이상으로 변화함에 따라 실내공기질(Indoor Air Quality : 이하 IAQ)이 인간에게 직접적인 미치는 영향에 대해 높은 관심을 나타내고 있다. 실내공기는 일정수준의 외기 도입이 없는 경우, 한정된 공간을 오염된 공기가 계속 순환하면서 오염물질이 누적될 수 있다. (중략)

• Journal of the Korean housing association
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• v.18 no.4
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• pp.59-67
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• 2007

The purposes of this study were to make clear the present condition of the TVOC and HCHO concentration after renovation in apartment houses. The field measurements of TVOC and HCHO concentration according to the Korea Test Method Standard for Indoor Air Quality were carried out in 4 subject apartment houses. The results are as follows; the TVOC concentration after renovation in apartment houses ranged from mean 0.35ppm to mean 5.08ppm and increased of $0.35{\sim}5.08ppm$. The TVOC concentration of 3 subjects exceeded the Indoor Air Quality Management standard for the newly-built apartment houses (0.58ppm). The HCHO concentration after renovation ranged from mean 0.13ppm to mean 0.43ppm and increased of $0.06{\sim}0.26ppm$. The HCHO concentration of 2 subjects exceeded the Standard (0.17ppm). As results of analysis on the relation of concentrated ascension and renovation elements, the amount and the types of finishing materials and adhesives affected concentrated ascension. Also, production method for installed or purchased furniture had certain effect on the TVOC and HCHO concentration ascension.

• Journal of environmental and Sanitary engineering
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• v.23 no.2
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• pp.35-45
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• 2008

In order to recommend criteria for the administration law on indoor air quality, this study was conducted to examine the distribution and the concentration of indoor air pollutants ($PM_{10},\;CO_2$, CO, HCHO, TBC, $NO_2$, Rn, VOCs, asbestos, $O_3$) in public facilities in the Chung-Nam area. The concentrations of indoor air pollutants were obtained from sixty seven public facilities such as a cinema, an office, a restaurant, a theater and an academy. This study was performed from August to December, 2005. The results of this study showed that the concentrations of indoor air pollutants such as $PM_{10},\;CO_2$, CO, HCHO, TBC, Rn and $O_3$ were less than the recommended limits. However, the average concentration of VOCs was $521.73{\mu}g/m^3$ (GM : $221.69{\mu}g/m^3$), which was higher than the recommended limit of $400{\mu}g/m^3$. Moreover, the average concentration of $NO_2$ was 345.66ppb (GM : 69.95ppb), which was higher than the recommended limit of 50 ppb. The correlation between the concentrations of indoor air pollutants and the type of facilities with respect to $CO_2$, TBC and Rn was statistically low (p<0.05). However, the correlation was high in terms of the CO and $O_3$ concentrations (p<0.01). No relationship between the indoor air pollutants and the type of facilities was observed for $PM_{10}$, VOCs and $NO_2$. The year of construction was compared to the concentrations of indoor air pollutants. Specifically, when the construction date was less than 3 years, the HCHO, VOCs and TBC concentrations were $44.75{\mu}g/m^3,\;555.07{\mu}g/m^3$ and $337.79CFU/m^3$, respectively. These concentrations were $120{\mu}g/m^3$ and $211.84CFU/m^3$ higher for VOCs and TBC than the concentrations obtained from the facilities more than 3 years. However, the concentration of HCHO was similar between the facilities older and younger than 3 years of age. Year, temperature, humidity and indoor air pollutant correlation analyses showed that temperature and humidity, temperature and TBC, temperature and $O_3,\;PM_{10}$ and $NO_2$, HCHO and VOCs, $CO_2$ and Rn had positive relationships. However temperature and Rn, humidity and $CO_2,\;CO_2$ and $O_3,\;O_3$ and Rn had negative relationships. Accordingly, it will be necessary to manage the factors affecting indoor air quality so that the residents can have a more comfortable and healthier living environment. Ultimately, the results of this study are expected to be utilized as baseline data.