• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1303-1308
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• 2011

In the modern society various types of transportation mode are utilized, among them the subway system is the one of the main transportation mode which more than 7.21 million people ride a day. Because of interests on the indoor air quality (IAQ) of underground public facilities, concerns on IAQ of subway system by many people are increasing. There are several approach to improve IAQ of subway station, such as installing platform screen door (PSD), frequent tunnel washing-out, and etc, however there has not been any attempt to improve IAQ of subway cabin inside. Most technologies for removing airborne particulate matters are known to be difficult to adopt on the subway cabin since the problem of maintenance cost. Therefore, the ultimate object of this study is a practical development of cabin air cleaning system which can reduce the concentration of airborne particles and harmful gases at the same time. The subway cabin air purifier (SCAP) was developed for removing particulate matters and gases pollutants inside a cabin. The whole system was designed and the roll-filter device was manufactured based on numerical prediction results. It is expected that SCAP could reduce indoor air pollutants in the subway cabin practically and it can be applied to other part of transportation vehicles.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.134-138
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• 2016

Porous $Co_3O_4$ spheres with bimodal pore distribution (size: 2-3 nm and ~ 30 nm) were prepared by ultrasonic spray pyrolysis of aqueous droplets containing Co-acetate and polyethylene glycol (PEG), while dense $Co_3O_4$ secondary particles with monomodal pore distribution (size: 2-3 nm) were prepared from the spray solution without PEG. The formation of mesopores (~ 30 nm) was attributed to the decomposition of PEG. The responses of a porous $Co_3O_4$ sensor to various indoor air pollutants such as 5 ppm $C_2H_5OH$, xylene, toluene, benzene, and HCHO at $200^{\circ}C$ were found to be significantly higher than those of a commercial sensor using $Co_3O_4$ and dense $Co_3O_4$ secondary particles. Enhanced gas response of porous $Co_3O_4$ sensor was attributed to high surface area and the effective diffusion of analyte gas through mesopores (~ 30 nm). Highly sensitive porous $Co_3O_4$ sensor can be used to monitor various indoor air pollutants.

• KIEAE Journal
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• v.17 no.5
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• pp.33-41
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• 2017

Purpose: Indoor air quality in residential buildings needs to be evaluated over the long term. In previous research, there has been an attempt to perform the health risk assessment of pollutants by using numerical models as a method of long-term evaluation. However, the numerical model of this precedent study has limitations that do not reflect the actual concentration distribution. Therefore, this study introduces the CRPS index, constructs a numerical model that can reflect the concentration distribution, and then presents a more accurate health risk assessment method using it. At this time, the pollutants are toluene, which is a typical material released from building materials. Method: CRPS index was applied to existing numerical model to reflect concentration distribution. This was used to calculate concentrations at adult breathing area and to use them for exposure assessment in a health risk assessment. After that, we entered adult data and conducted a health risk assessment of toluene. Results: The non-carcinogenic risk of toluene was calculated to be 0.0060. This is 5% smaller than the existing numerical model, meaning that it is more accurate to predict the pollutant risks. This value is also lower than the US EPA reference value of 1. Therefore, under the conditions of this study, long-term exposure of adults to toluene has no impact on health.

• 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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.68-69
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• 2020

Recently, the problem of air pollution is drawing attention as a social problem worldwide. Particularly, fine dust is the biggest issue among air pollutants, and it is analyzed that fine dust is generated from air pollutants such as burning fossil fuels such as petroleum or coal, or exhaust gases from automobiles. In addition, yellow dust originating from China adjacent to Korea flows into the Korean Peninsula in a western wind, causing the concentration of fine dust to deteriorate. Fine dust is a harmful substance to the human body such as asthma or respiratory disease, and awareness of the risk is also increasing to a degree designated as a primary carcinogen. In this study, as a method for improving the indoor air quality, the Properties of the matrix according to the mixing ratio of powdered activated carbon based on blast furnace slag are reviewed. The flexural strength and compressive strength were measured, and a fine dust concentration measurement experiment will be conducted later.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.540-547
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• 2021

Background: Indoor air pollutants are caused by a number of factors, such as coming in from the outside or being generated by internal activities. Typical indoor air pollutants include nitrogen dioxide and carbon monoxide from household items such as heating appliances and volatile organic compounds from building materials. In addition there is carbon dioxide from human breathing and bacteria from speaking, coughing, and sneezing. Objectives: According to recent research results, most indoor air pollution is known to be greatly affected by internal factors such as burning (biomass for cooking) and various pollutants. These pollutants can have a fatal effect on the human body due to a lack of ventilation facilities. Methods: We fabricated a polydopamine (PDA) layer with Ti substrates as a coating on supported glass fiber fabric to enhance its photo-activity. The PDA layer with TiO₂ was covalently attached to glass fiber fabric using the drop-casting method. The roughness and functional groups of the surface of the Ti substrate/PDA coated glass fiber fabric were verified through infrared imaging microscopy and field emission scanning electron microscopy (FE-SEM). The obtained hybrid Ti substrate/PDA coated glass fiber fabric was investigated for photocatalytic activity by the removal of ammonia and an epidermal Staphylococcus aureus reduction test with lamp (250 nm, 405 nm wavelength) at 24℃. Results: Antibacterial properties were found to reduce epidermal staphylococcus aureus in the Ti substrate/PDA coated glass fiber fabric under 405 nm after three hours. In addition, the Ti substrate/PDA coated glass fiber fabric of VOC reduction rate for ammonia was 50% under 405 nm after 30 min. Conclusions: An electron-hole pair due to photoexcitation is generated in the PDA layer and transferred to the conduction band of TiO₂. This generates a superoxide radical that degrades ammonia and removes epidermal Staphylococcus aureus.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.4
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• pp.436-445
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• 2014

Objectives: Time-activity studies have become an integral part of comprehensive exposure assessment and personal exposure modeling. The aims of this study were to estimate exposure levels to nitrogen dioxide($NO_2$) and volatile organic compounds(VOCs), and to compare estimated exposures by using time-activity patterns and indoor air concentrations. Methods: The major microenvironments for office workers were selected using the Time-Use Survey conducted by the National Statistical Office in Korea in 2009. A total of 9,194 and 6,130 workers were recruited for weekdays and weekends, respectively, from the Time-Use Survey. It appears that workers were spending about 50% of their time in the house and about 30% of their time in other indoor areas during the weekdays. In addition, we analyzed the time-activity patterns of 20 office workers and indoor air concentrations in Daegu using a questionnaire and time-activity diary. Estimated exposures were compared with measured concentrations using the time-weighted average analysis of air pollutants. Conclusions: According to the time-activity pattern for the office workers, time spent in the residence indoors during the summer and winter have been shown as $11.12{\pm}2.20$ hours and $12.48{\pm}1.77$ hours, respectively, which indicates higher hours in the winter. Time spent in the office in the summer has been shown to be 1.5 hours higher than in the winter. The target pollutants demonstrate a positive correlation ($R^2=0.076{\sim}0.553$)in the personal exposure results derived from direct measurement and estimated personal exposure concentrations by applying the time activity pattern, as well as measured concentration of the partial environment to the TWA model. However, these correlations were not statistically significant. This may be explained by the difference being caused by other indoor environments, such as a bar, cafe, or diner.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.2
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• pp.185-190
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• 1995

Recently, because of the worse of the air pollution, the excessive airtught of building and the inferiority of air conditioning system, the development of high efficiency air purification technology was enlarged to the environmental improvement of an indoor or a harmful working condition. The air purification technology has used chemical filters or charcoal filters or charcoal to remove hazardouse gaseous pollutants (SO$_{x}$, NO$_{x}$, NH$_{3}$, etc.) by air pollutant control technology, but they have many problems of high pressure loss, short life, wide space possession, and treatment of secondary wastes. For these reason, the object of reasearch shall be hazardous gaseous pollutants removal by the surface discharge induced plasma chemical process that is A.C. discharge of multistreams applied A.C. voltage and frequency between plane induced eletrode and line discharge eletrode of tungsten, platinum or titanium with a high purified alumina sheet having a film-like plane. As a result, the control performance for hazardous gaseous pollutants showed very high efficiency in the normal temperature and pressure. Also, after comtact oxidation decomposition of harmful gaseous pollutants, the remainded ozone concentration was found much lower than that of ACGIH or air pollution criteria in Korea.rea.

• KIEAE Journal
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• v.5 no.3
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• pp.41-48
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• 2005

Before occupation of an apartment housing, the builders are required to inform the test result of IAQ to the public. However, there is no simplified method to predict IAQ before measurement of pollutant concentration. In this study, a simplified way of predicting IAQ based on the distribution of indoor pollutant concentration is proposed. 7 different cases of air change rate have been simulated through CFD analysis to get the distribution ratio of each pollutant material and then simplified functions were used with CRIAQ1 values derived from CFD simulation to evaluate by comparing the influence of each material in the indoor pollutant concentration. Again, a lot of efforts which can improve the indoor air quality have been performed. Materials used in indoor space are labeled with their pollutant emission level. Installation of ventilation system in residential buildings will be regulated by a building codes sooner or later. But it is important to understand the fact that layout of walls, location or size of openings will influence the indoor air flow and pollutant concentration. And location of emitting material influences to indoor air pollutants distribution. But until now there is few recognition and consideration of these factors. Therefore, in this paper the effects of these factors is proved and some kind of guideline is made for designers after a comparison of typical apartment floor plan and a new type plan with their average pollutant concentration and its distribution of each room. CFD(Computational Fluid Dynamics) program was used to show the indoor air flow and pollutant concentration distribution. For this purpose, a typical $100m^2$ apartment floor plan was chosen as a case study model and several alternatives were reviewed to improve the IAQ performance. The simulation took place in the condition of natural ventilation through windows.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.271-278
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• 2021

This paper is a study on the implementation of smart filter system that recognizes the external environment and automatically removes pollutants according to pollution level. Recently, the occurrence of various pollutants in indoor and outdoor space has adversely affected the human body. Especially, various fine dust generated in the atmosphere becomes worse in closed residential space or office space. Although air pollution can be temporary lowered through ventilation, it is difficult to respond to fine dust changes in real time, and such problems become serious in the space where many people reside, such as at home or industry. Therefore, it is necessary to measure the pollution level of fine dust inside the residential space in real time and to reduce the pollution of indoor ventilation through automatic ventilation with the outside. To improve these problems, this paper proposes the implementation of smart filter system for external environment recognition. The structure of smart filter system that automatically measures air quality inside and outside, removes pollutants, implements the function, and confirms the operability by manufacturing prototypes. Finally, the effectiveness of the smart filter system for solving fine dust problems was examined.