• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.183-190
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• 2021

This study is a study on the implementation and operation of smart air cleaning system to improve indoor air quality. Recently, the problem of indoor air quality is getting serious due to various environmental factors. In this study, to improve the problems of indoor air quality, we implement an air cleaning system using IoT sensor. In particular, we proposed a system that can measure air pollution in real time and change different air flow paths according to pollution level. Through this, we examined efficient air quality improvement, extension of filter life, and system energy reduction. In addition, the main functions of the indoor air quality improvement system were constructed and prototypes were manufactured to confirm the operability. Finally, the utility of fine dust resolution through the implementation of the indoor air quality improvement system was examined.

• Journal of Environmental Health Sciences
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• v.38 no.4
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• pp.300-310
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• 2012

Objectives: Indoor air quality problems in public spaces have recently become a very important issue in South Korea, because many spend a long time every day indoors. In this study, an extensive literature review was performed on the subject of suspended bacteria and fungi in public facilities. The objective of this study was to evaluate the extent and types of suspended bacteria and fungi in indoor air in South Korea. This study will provide direction to the research in the field of indoor air. Methods: Article reviews was conducted using a search engine and the following keywords; 'bacteria', 'total suspended bacteria', 'fungi' and 'indoor air' from published articles since 2000. Results: Most of the places of measurement were schools, kindergartens, childcare centers and general hospitals. The highest concentrations of total suspended bacteria and fungi were found in schools and kindergartens. Some public facilities exceeded the standard of 800 CFU/$m^3$. There were few studies on other suspended bacteria: Gram Negative Bacteria, Staphylococcus and Klebsiella pneumoniae. Conclusions: It appears that more studies with intensive controls are needed. It was found that schools and kindergartens were most susceptible to microbial indoor air pollution. These results may be able to suggest an indoor standard for suspended bacteria and fungi in South Korea.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.217-223
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• 2019

The purpose of this study was to measure the indoor air quality of small-scale apartments and then proposed a method to improve the indoor air quality of the small-scale apartments by comparing with the result of indoor air quality in the Clean-Healthy House. In case of formaldehyde, a highly volatile organic compound, the concentrations of indoor measured both in small-scale apartments and the Clean Healthy houses did not exceed- the guideline of Korea. The guideline of Korea for acetaldehyde was not available, so the guidelines of Japan and the World Health Organization were used to measure the concentration of acetaldehyde. The study results demonstrated that three out of seven small-scale apartments investigated exceeded the guideline of Japan; and the preliminary research on the Clean-Health Houses was low at about 30-60% of the guideline of Japan. The result of the VOCs measurement showed that toluene, ethylbenzene, and styrene in some small-scale apartments exceeded the guideline of Korea. However, the Clean-Healthy Houses in the previous studies did not exceed the guideline of Korea with regard to all the pollutants. Therefore, this study suggests the application of the construction standards of the Clean-Healthy house in order to improve the indoor air quality of small-scale apartments. In addition, the current study anticipates that improvement of the indoor air quality in the residential environments should be universally applied, not limited to the type and size of the residence.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.183-192
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• 2002

Indoor air quality is affected by source strength of pollutants, ventilation rate, decay rate, outdoor level and so on. Although technologies exist to measure these factors directly, direct measurements of all factors are impractical in most field studies. The purpose of this study was to develop an alternative methods to estimate these factors by multiple measurements. Daily indoor and outdoor NO$_2$concentrations for 21 days in 20 houses in summer and winter, Seoul. Using a mass balance model and linear regression analysis, penetration factor (ventilation divided by sum of air exchange rate and deposition constant) and source strength factor(emission rate divided by sum of air exchange rate and deposition constant) were calculated. Subsequently, the ventilation and source strength were estimated. During sampling period, geometric mean of natural ventilation was estimated to be 1.10$\pm$1.53 ACH, assuming a residential NO$_2$decay rate of 0.8 hr$^{-1}$ in summer. In winter, natural ventilation was 0.75$\pm$1.31 ACH. And mean source strengths in summer and winter were 14.8ppb/hr and 22.4ppb/hr, respectively. Although the method showed similar finding previous studies, the study did not measure ACH or the source strength of the house directly. As validation of natural ventilations, infiltrations were measured with $CO_2$tracer gas in 18 houses. Relationship between ventilation and infiltration was statistically correlated (Pearson r=0.63, p=0.02).

• Analytical Science and Technology
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• v.18 no.4
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• pp.344-354
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• 2005

This study was carried out to evaluate the performance of a small chamber sampling and analytical method for the measurement of total volatile organic compounds (TVOC) and formaldehyde (HCHO) emission from building materials. While VOC was determined by the adsorbent tube sampling and sequential thermal desorption coupled with GC/MSD analysis, formaldehyde sampled with DNPH-silica cartridge was analyzed by HPLC. Wide-range performance criteria such as repeatability, desorption efficiency, emission chamber recovery test, duplicate precision, breakthrough volume and method detection limits were investigated for the evaluation of small chamber method. The overall precision of the small chamber sampling and analytical methods was estimated within 20~30% for target compounds. In conclusion, this study demonstrated that the small chamber sampling and analytical method can be reliably applied for the measurement of building materials pollutants.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.189-190
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• 2021

Recently, the spread of intense social distancing and untact culture due to COVID-19 has increased the time spent indoors. In addition, according to the International Cancer Institute, fine dust was classified as a first-class carcinogen, a substance found to be carcinogenic, such as asbestos and benzene. As a result, interest in indoor air quality is increasing, and many studies are underway to reduce air pollutants. This study is a basic experiment of a board made to improve indoor air quality. The basic characteristics of the board, flexural strength and compressive strength, are analyzed and the results of the test are as follows. Experiments have shown that flexural strength and compressive strength tend to decrease as the replacement rate of hydrocarbons increases. It is believed that the strength of the sludge has decreased due to the increase in internal voids due to the increase in non-surface area, volume and diameter of microfiber as it undergoes the carbonation process. In addition, it is believed that the amount of moisture needed for curing during the mixing process was reduced due to the absorption of hydrocarbons.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.77-82
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• 2022

The effect of indoor air pollution on the human body is greater and more dangerous than outdoor air pollution. In general, a person stays indoors for a long time, and in a closed room, pollutants are continuously accumulated and the polluted air is better delivered to the lungs. Especially in the case of young children, it is very sensitive to indoor air and it is fatal. In addition, methods to reduce indoor air pollution, which cannot be ventilated with more frequent indoor activities and continuously increasing external fine dust due to Covid 19, are becoming more important. In order to improve the problems of the existing autonomous driving air purifying robot, this paper divided the map and Upper Confidence bounds applied to Trees(UCT) based algorithm to solve the problem of the autonomous driving robot not sterilizing a specific area or staying in one space continuously, and the problem of children who are vulnerable to indoor air pollution. We propose a space-adaptive autonomous driving air purifying robot for a green smart school that can be improved.

• Journal of Korean Society for Atmospheric Environment
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• v.3 no.1
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• pp.65-73
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• 1987

Indoor air pollution problems, in fact, have been neglected due to the unawareness of its seriousness and the lack of accumulated data. Recently, some movement of research and regulations, however, have been made for several indoor air pollutants. In this study, one of the carcinogenic polynuclear aromatic hyrocarbon, Benzo(a) pyrene in indoor airborne particulate, was measured and analyzed to estimate emission strength of BaP from an unvented kerosene heater and to know its level in indoor environment with use of a kerosene heater and a wood-burning fireplace. By the measurement of BaP level in a dark room with air exchange rate of app. 3.0, BaP emission strength of a kerosene heater (11,000Btu/hr) was estimated to be 326.6ng/hr (or 29.7 ng/$10^3$ Btu). With 4-hr operation a day of the kerosene heater in an apartment, the BaP level became 2.97ng/m$^3$ from 0.27ng/m$^3$ of background level. The operation of a wood-burning fireplace app. 2hr a day, on the other hand, increased the BaP level from 0.16ng/m$^3$ of background to 3.53ng/m$^3$. So proper ventilation must be considered seriously when unvented heating facilities are used in indoor environment.

• Journal of Environmental Health Sciences
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• v.35 no.2
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• pp.78-85
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• 2009

In this study, the hazard rate of the indoor environment of Children's Educational Facilities in Seoul was conducted, in order to determine how the indoor environments of these facilities, where infants and children spend the most time of their away from home day, can effect their health. The way of measurement and analysis were done according to the Indoor Air Quality Standard Method, and the Risk Assessment was accomplished with several significant ways - Hazard Identification, Exposure Assessment, Dose-response Assessment, Risk Characterization, which are deighed by National Research Council (NRC). On each exposure factors, documentary and questionary research such as Epidemiological study and Toxicological study were conducted. The result of the CTE (Central tendency exposure) of Formaldehyde and Benzene by Monte-Carlo simulation was $6.79{\times}10^{-6}$, $2.50{\times}10^{-7}$ which in the case of Formaldehyde exceeded the permitted standard ($10^{-6}$) of the US EPA. The RME(Reasonable maximum exposure) was $7.31{\times}10^{-5}$, $2.65{\times}10^{-6}$ which did not exceed $10^{-4}$, the maximum permitted standards in the US EPA.

• Journal of the Korean Society of Combustion
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• v.8 no.2
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• pp.7-16
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• 2003

The transfer of air pollutants between passenger room and service room in train are investigated by the computational analysis. The effects of service room temperature, inlet velocity, initial concentration and heating are studied. The flow induced by the difference of density between two rooms is found to take the major role in transfer of polluted air. Low temperature of service room enhances the polluted air flow into passenger room along the floor. Exhaust fan above the door between two rooms is not effective for this case. Strong inlet flow is found to suppress polluted air flow from service room. The heating of passenger room can promote air pollution.