• Journal of Environmental Science International
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• v.15 no.10
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• pp.913-918
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• 2006

Despite the wide distribution of air pollutants, the concentrations of indoor air pollutants may be the dominant risk factor in personal exposure due to the fact that most people spend an average of 80% of their time in enclosed buildings. Researches for improvement of indoor air quality have been developed such as installation of air cleaning device, ventilation system, titanium dioxide$(TiO_2)$ coating and so on. However, it is difficult to evaluate the magnitude of improvement of indoor air quality in field study because indoor air quality can be affected by source generation, outdoor air level, ventilation, decay by reaction, temperature, humidity, mixing condition and so on. In this study, evaluation of reduction of formaldehyde and nitrogen dioxide emission rate in indoor environments by $TiO_2$ coating material was carried out using mass balance model in indoor environment. we proposed the evaluation method of magnitude of improvement in indoor air quality, considering outdoor level and ventilation. Since simple indoor concentration measurements could not properly evaluate the indoor air quality, outdoor level and ventilation should be considered when evaluate the indoor net quality.

• Journal of Environmental Health Sciences
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• v.34 no.3
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• pp.183-187
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• 2008

Indoor air quality can be affected by indoor sources, ventilation, decay, and outdoor levels. Various indoor and out-door combustion sources produce nitrogen dioxide ($NO_2$), which is a by-product of high temperature fossil fuel combustion. Especially, the presence of gas ranges and smoking have been identified as major factors contributing to indoor $NO_2$ exposures. In this study, we compared an industrial complex area with a country area by assessing the personal exposure to $NO_2$with measurements of indoor and outdoor $NO_2$ levels in residences and by house characteristics and questionnaire. Personal exposure concentrations were significantly correlated with indoor $NO_2$ concentrations of residences in both the industrial complex area and the country area with correlation coefficients of 0.561 and 0.664, respectively, compared to outdoors. Multiple regression analysis, indicated that indoor $NO_2$ levels in residences were only affected by outdoor levels (p = 0.000) in spite of higher indoor sources such as smoking. Therefore, it is suggested that outdoor air quality as well as indoor air quality should be considered in the reduction of the personal exposure to air pollutants.

• International Journal of High-Rise Buildings
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• v.8 no.1
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• pp.71-82
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• 2019

The purpose of this study is to evaluate the indoor air quality (IAQ) and energy benefits of a dedicated outdoor air system (DOAS) and compare them with a conventional variable air volume (VAV) system. The DOAS is a decoupled system that supplies only outdoor air, while reducing its consumption using an enthalpy wheel. The VAV system supplies air that is mixed outdoor and transferred indoor. The VAV has the issue of unbalanced ventilation in each room in multiple zones because it supplies mixing air. The DOAS does not have this problem because it supplies only outdoor air. That is, the DOAS is a 100% outdoor air system and the VAV is an air conditioning system. The transient simulations of carbon dioxide concentration and energy consumption were performed using a MATLAB program based on the thermal loads from the model predicted by the TRNSYS 18 program. The results indicated that when the air volume is large, such as in summer, the distribution of air is not appropriate in the VAV system. The DOAS however, supplies the outdoor air stably. Moreover, in terms of annual primary energy consumption, the DOAS consumed approximately 40% less energy than the VAV system.

• Journal of Environmental Health Sciences
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• v.22 no.4
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• pp.43-48
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• 1996

Indoor air quality(IAQ) in museum is very important for protection of cultural properties. In our study, we measured air pollutants($NO_x, NH_3, SO_2, O_3$, CO, $CO_2$, TSP), temperature and humidity to evaluate IAQ of national central museum. Indoor carbon dioxide and TSP concentrations were higher than outdoor concentrations. Temperature, huinidity and TSP had large deviation depending on air conditioning operates or not. Indoor gas phase pollutants except $CO_2$ were lower than outdoor concentrations, but $SO_2$ concentration was high in storage. $CO_2$ and TSP were influenced by the number of spectators.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.137-142
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• 2018

The purpose of this study is to contribute to the improvement of indoor air quality management in dental clinic by investigating the level of indoor air quality recognition among dental clinic workers. The questionnaire survey was conducted for about 4 weeks from May 20 to June 20, 2018 in dental clinics located in Jeollanamdo area and 143 were used as the analysis data. The method of indoor air quality management in dental clinic was preferred to "natural ventilation" method and the number of natural ventilation was 1 to 2 times per day and the results of survey on indoor environment satisfaction showed that satisfaction level was lowest in noise and smell items. The types of subjective symptoms experienced by workers working at dental clinics are "cough", "eye burn", and "headache" and a survey on the degree of the relationship between subjective symptoms and indoor air quality showed that 94.4% (135) of respondents answered "very relevant" and "slightly related". As a result of multiple regression analysis, the variables affecting the indoor air quality satisfaction of the dental clinic staff were analyzed as the items such as lighting, noise, main work, number of patients, comparing indoor and outdoor air quality and among them, "comparing indoor and outdoor air quality" was analyzed as having a great influence. To improve the indoor air quality satisfaction of dental clinic worker adequate ventilation, designate the person responsible for the indoor air quality management and periodic measurement efforts will be necessary.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.160-165
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• 2005

Schools have significant and serious indoor environmental health problem, of which indoor air quality (IAQ) in school building may affect the health of the students and indirectly affect learning performance. Schools are of special concern when regarding indoor exposure to air pollutants, because students are particularly sensitive to pollutants and spend a significant amount of time in that environment. Therefore researches for improvement of indoor air quality have been developed such as installation of air cleaning device, ventilation system, titanium dioxide(TiO2) coating and so on. However, it is difficult to evaluate the magnitude of improvement of indoor air quality in field study because indoor air quality can be affected by source generation, outdoor air level, ventilation, decay by reaction, temperature, humidity, mixing condition and so on. In this study, evaluation of reduction of formaldehyde emission rate in school indoor environments by far-Infrared ray coating material was carried out using mass balance model in indoor environment. we proposed the evaluation method of magnitude of improvement in indoor air quality, considering outdoor level and ventilation. Since simple indoor concentration measurements could not properly evaluate the indoor air quality, outdoor level and ventilation should be considered when evaluate the indoor air quality.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.61-61
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• 1995

Volatile organic compounds(VOCs) are of concern for their potential chronic toxicity, their suspected role in the formation of smog, and their suspected role in destruction of stratospheric ozone. Present study evaluated the exposures to selected VOCs in three microenvironments: 2 chlorinated and 5 aromatic VOCs in the indoor and outdoor air, and 5 aromatic VOCs in the breathing zone air of gas-service station attendants. With permissible Quality Assurance and Quality Control performances VOC concentrations were measured 1) to be higher in indoor air than in outdoor air, 2) to be higher in two Taegu residential areas than in a residential area of Hayang, and 3) to be higher in the nighttime than in the daytime. Among five aromatics, Benzene and Toluene were two most highly measured VOCs in breathing zone air of service station attendants. Based on the sum of VOC concentrations, the VOC exposure during refueling was estimated to be about 10% of indoor and outdoor exposures. For Benzene only, the exposure during refueling was estimated to cause about 52% of indoor and outdoor exposure. The time used to calculate the exposures was 2 minutes for refueling and 24 hours for indoor and outdoor exposures.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.447-459
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• 1995

Volatile organic compounds(VOCs) are of concern for their potential chronic toxicity, their suspected role in the formation of smog, and their suspected role in destruction of stratospheric ozone. Present study evaluated the exposures to selected VOCs in three microenvironments: 2 chlorinated and 5 aromatic VOCs in the indoor and outdoor air, and 5 aromatic VOCs in the breathing zone air of gas-service station attendants. With permissible Quality Assurance and Quality Control performances VOC concentrations were measured 1) to be higher in indoor air than in outdoor air, 2) to be higher in two Taegu residential areas than in a residential area of Hayang, and 3) to be higher in the nighttime than in the daytime. Among five aromatics, Benzene and Toluene were two most highly measured VOCs in breathing zone air of service station attendants. Based on the sum of VOC concentrations, the VOC exposure during refueling was estimated to be about 10% of indoor and outdoor exposures. For Benzene only, the exposure during refueling was estimated to cause about 52% of indoor and outdoor exposure. The time used to calculate the exposures was 2 minutes for refueling and 24 hours for indoor and outdoor exposures.

• Journal of Environmental Science International
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• v.6 no.6
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• pp.637-644
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• 1997

The purpose of thins study was to quantitatively determine the Indoor Infiltration of pollutants of outdoor origin. The relationship between Indoor and outdoor air is dependent, to a large extent. on the rate of k exchange between these two environments. Mean Indoor/outdoor ratios measured from thins study were: 0.70 for HNO3; 1.60 for HNO2: 0.56 far SOg: 1.30 for mf3: 0.96 for PM2.5(dP<2.5mm: 0.89 for SO4a': 0.87 for NO3· and 0.79 for NH4 'Mean Indoor concentrations for PMa s, SO4a., HNO9, NO3 and NIL' were similar to outdoor levels. Indoor HNO2 and mB3 values were h19her than outdoors. However, the Indoor level of SO2 was lower than ambient level.

• Journal of the Korea Furniture Society
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• v.26 no.1
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• pp.71-76
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• 2015

It is important thing that air quality affects human health. And It is more important thing that Indoor Air Quality more affects human health than Outdoor Air Quality. The cause of that is indoor air pollutants are more absorbed than outdoor air pollutants. By the way, in case of Multi-use facility for example office, department store, school etc., it has a feature that there are more people than any other buildings. therethrough, effects of Indoor Air Quality of Multi-use facility affect more people's health than Indoor Air Quality of any other buildings. However, in multi-use facility, specifically retail store, chemical treated materials are used for interior finishing, showcase finishing and product finishing because esthetic element is more added for detention of customer. Consequently, in place where demands brisk sales, possibility that indoor air is polluted by VOCs is high. This study considered retail store's Indoor Air Quality. as result of experiment, figure of department store's air pollution exceed about 5~20 times in guideline of multi-use facility's Indoor Air Quality in any kind of shop of department store (guideline : $500{\mu}g/m^3$).