• Journal of Korean Society for Atmospheric Environment
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• v.30 no.3
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• pp.233-244
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• 2014

The objective of this study was to explore the characteristics of concentration of indoor air pollutants, such as $PM_{10}$, $CO_2$, and $NO_2$, measured by tele-monitoring system in a Seoul Metropolitan underground railway station from January 1, 2008 to December 31, 2012. The annual average concentration of indoor air pollutants actually varied over a wide range and was found to exhibit marked variation with time and measurement sites (tunnel inlet, platform, and concourse). After installing platform screen doors, the average $PM_{10}$ concentration on platform and concourse was decreased by 43.8% and 31.2%, respectively during the study periods. The relationship between the concentration of $PM_{10}$ and meteorological parameters (relative humidity and rainfall) or the Asian dust events was regarded as statistically significant. The correlations between the number of boarding/alighting passengers and $PM_{10}$, $CO_2$, and $NO_2$ were calculated. A p-value of less than 0.01 was regarded as significant except $NO_2$. The I/O ratio of $PM_{10}$ concentration was elevated after a congested time (about 08:00 am). The average I/O ratios of $NO_2$ were observed in concourse and platform on 03:00 am with $1.76{\pm}0.91$ and $1.50{\pm}0.51$, respectively. The average daily variation of standard excess rate of $PM_{10}$ and $NO_2$ concentration in concourse and platform was investigated. The highest standard excess rate was observed on 21:00 (09:00 pm).

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.527-539
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• 2018

The subway used by many passengers is required to maintain a safe and comfortable environment and PSD (Platform Screen Door) must be installed in the platform after reinforcing the standard in 2003. In the previous research, in case of subway fire to control it, it is necessary to design the optimal ventilation and smoke exhaust system according to equipment capacity of the smoke exhaust system. Therefore, in this study, based on the results of previous research, three-dimensional numerical analysis was performed for the CO gas and smoke flow by the subway ventilation system in case of platform fire. As a result of this study, it was found that in case of emergency, if only the upper-level smoke exhaust system is activated, the risk of evacuation is high due to CO gas (653.8 ppm) and smoke concentration ($768.4mg/m^3$). And when all the smoke exhaust systems are activated and only the fire side PSD is opened, CO gas (36.0 ppm) and smoke concentration ($26.2mg/m^3$) are detected and the propagation range of smoke flow was reduced. When all the smoke exhaust systems are activated and only the fire side PSD is closed, it was analyzed as the most effective ventilation mode in the evacuation environment due to the absence of smoke-recirculation.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.1
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• pp.74-85
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• 2013

Since the underground transportation system is a closed environment, indoor air quality problems may seriously affect many passengers' health. The purpose of this study was to understand $PM_{10}$ characteristics in the underground air environment and further to quantitatively estimate $PM_{10}$ source contributions in a Seoul Metropolitan subway station. The $PM_{10}$ was intensively collected on various filters with $PM_{10}$ aerosol samplers to obtain sufficient samples for its chemical analysis. Sampling was carried out in the M station on the Line-4 from April 21 to 28, July 13 to 21, and October 11 to 19 in the year of 2010 and January 11 to 17 in the year of 2011. The aerosol filter samples were then analyzed for metals, water soluble ions, and carbon components. The 29 chemical species (OC1, OC2, OC3, OC4, CC, PC, EC, Ag, Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Si, Ti, V, Zn, $Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$, $Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$) were analyzed by using ICP-AES, IC, and TOR after proper pretreatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the $PM_{10}$ sources and then six sources such as biomass burning, outdoor, vehicle, soil and road dust, secondary aerosol, ferrous, and brakewear related source were classified. The contributions rate of their sources in tunnel are 4.0%, 5.8%, 1.6%, 17.9%, 13.8% and 56.9% in order.

• Journal of Environmental Health Sciences
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• v.47 no.5
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• pp.410-424
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• 2021

Background: Subway stations have the characteristics of being located underground and are a representative public-use facility used by an unspecified number of people. As concerns about indoor air quality (IAQ) increase, various management measures are being implemented. However, there are few systematic studies and cases of long-term continuous measurement of underground station air quality. Objectives: The purpose of this study is to analyze changes and factors influencing IAQ in subway stations through real-time continuous long-term measurement using IoT-based IAQ sensing equipment, and to evaluate the IAQ improvement effect of a bio-filter system. Methods: The IAQ of a subway station in Seoul was measured using IoT-based sensing equipment. A bio-filter system was installed after collecting the background concentrations for about five months. Based on the data collected over about 21 months, changes in indoor air quality and influencing factors were analyzed and the reduction effect of the bio-filter system was evaluated. Results: As a result of the analysis, PM₁₀, PM_2.5, and CO₂ increased during rush hour according to the change in the number of passengers, and PM₁₀ and PM_2.5 concentrations were high when a PM warning/watch was issued. There was an effect of improving IAQ with the installation of the bio-filter system. The reduction rate of a new-bio-filter system with improved efficiency was higher than that of the existing bio-filter system. Factors affecting PM_2.5 in the subway station were the outdoor PM_2.5, platform PM_2.5, and the number of passengers. Conclusions: The IAQ in a subway station is affected by passengers, ventilation through the air supply and exhaust, and the spread of particulate matter generated by train operation. Based on these results, it is expected that IAQ can be efficiently improved if a bio-filter system with improved efficiency is developed in consideration of the factors affecting IAQ and proper placement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.213-223
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• 2018

This study assessed the maintenance plan of the Shimbashi-Toranomon Development Area in Japan, which has recently been completed using the three-dimensional road system. In the main relevant law system, a three-dimensional road system, which enables the construction of buildings above and below the road, was applied. The specific construction regulations applying the financing power and knowledge of private business operators were applied. In the development district, city maintenance guidelines were established, and housing and shopping malls were regulated. This purpose was to promote change, unity of distance, effective use of land, and continuous urban revitalization with charm and vitality. The main features of the maintenance plan were accessibility and greenery, comfort and a sophisticated design, and a maintenance concept utilizing historical buildings and road space through the participation of local residents and the opinions of related committees. In addition, in the case of the construction of the upper and lower roads, the construction restrictions were relaxed, and the separation of the roads and the undergrounding of electric poles were promoted. The main aim was to improve the convenience of the residents and produce a pleasant road landscape.

• Journal of the Korean earth science society
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• v.40 no.3
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• pp.272-282
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• 2019

Although the knowledge of current seismicity is a critical information for making and implementing effective earthquake-related policy, the detailed seismicity information of the metropolitan areas with high-population density has been largely underestimated due to the high-level of cultural noise and small earthquake magnitude. This study presents 12 earthquakes including 2 earthquakes previously known and 10 additional earthquakes occurred from 2010 to 2017 in Busan, but they were unreported by the Korea Meteorological Administration. Matched filter technique is used to detect micro-earthquakes. Although the epicenters of micro-earthquakes though present a distinguished linearity, a correlation with faults in the area is unknown. A repeated micro-seismicity suggests that there are subsurface structures responsible for observed events. If large earthquakes occur along the fault in Busan, they may cause catastrophic natural disasters. Given the fact that the recent earthquakes did not accompany any surface signatures, it is highly recommended that the current micro-seismicity be investigated, and updated seismicity information be incorporated into establishing active fault maps in Korea.

• Particle and aerosol research
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• v.18 no.1
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• pp.9-21
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• 2022

In this study, a novel antiviral coating method for the air filtration system of subway station was investigated. Using dry aerosol coating process, we developed a high-performance antiviral air filter with spark discharger and carbon brush type ionizer. Silver nanoparticles were produced by a spark discharge generation system with ion injection system and were used as antiviral agents coated onto a medium grade air filter. The pressure drop, filtration efficiency, and antiviral ability of the filter against aerosolized MS2 virus particles as a surrogate of SARS-CoV-2 virus were tested with dust contamination. Dust contamination caused the increase of the filtration efficiency and pressure drop, while the antiviral agents (in this study, silver nanoparticles) coating did not have any significant effect on the filtration efficiency and pressure drop. Using these properties, we suggested a novel method to maximize the antiviral performance of the antiviral air filter that was contaminated by dust particles. Moreover theoretical analysis of antiviral ability with dust contamination and re-coated antiviral agents was carried out using a mathematical model to calculate the time-dependent antiviral effect of the filter under actual conditions of subway station. Our model can be used to apply on antiviral air filtration system of subway station for prevention of pandemic diffusion, and predict the life cycle of an antiviral filter.

• Particle and aerosol research
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• v.18 no.3
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• pp.51-59
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• 2022

In this work, virion concentration and its dose changes by HVAC and air cleaners were estimated in a subway station platform to control airborne infection of SARS-CoV-2. Collection efficiencies with particle size were measured for the air filter equipped in a HVAC in one subway station in Daejeon. Indoor PM_2.5 changes according to outdoor PM_2.5 with time were also measured to estimate air infiltration rate in the subway station platform. When infected persons generate virions by 10⁴, 10⁵, 10⁶, 3 × 10⁶ and 5 × 10⁶ h^-1 in a 2,400 m³ volume platform, the concentration and dose were estimated as 9, 92, 275 and 458 virions/m³ and 4, 43, 130 and 217 virions after 1 hour exposure, respectively. The concentration and dose were reduced by 70%, and 64%, respectively by operations of both HVAC (with a flow rate of 16,000 m³/h, MERV 11) and ten air cleaners(with total CADR 10,740 m³/h) compared to those without operation of both HVAC and air cleaners. However, virion dose in the platform was estimated to be too low at the general conditions due to a large space, a high air infiltration (3 h^-1) and a short residence time (usually < 10 mins) in the platform irrespective of the operations of HVAC or air cleaners. HVAC with filters and air cleaners would be more necessary in the concourse or shopping areas in the subway stations to reduce the infection dose from a few hundred to several tens virions in a hour.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2007.05a
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• pp.204-209
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• 2007

As people are getting interested in themselves ever than before, the value of culture industry which can satisfy their emotions has been considered much more important. According to this, in terms of the 'space', it is better to represent 'space' not just as a functional space, but the human-centered and making human and nature together. In this society, the most human-centered design can be achieved by pursuing value which is friendlier to nature. And it is sure that the interior design that completes life quality as well as emotions of human will be common in near future. There already has been a try 'Green interior' in subway station in variety ways, and now it is needed to make indoor display in Seoul subway station different in order to satisfy human emotions. If culture space in Seoul subway station applied eco-element interacts with indoor environment, it is surely expected that people have better feeling on subway station as well as help eliminate negative elements which underground have had. In culture space, there are many advantages for displaying space into 'nature', that is, natural space represents the best comfortable and agreeable space, and future-oriented design when it gets interacted with environment. Application of 'Green interior' in Seoul subway station makes special place ness by its symbol and image, so that it derives people to have more natural and comfortable movement distance in subway station, offers more comfortable and cozy place as well. Furthermore, it makes people very moved by experiencing the most special culture space that they have ever had.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.927-935
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• 2009

Environmental shape objects not only play a part as various cultural facilities but also symbolize local unique culture beyond the limit of functional role. Therefore subway environmental shape objects should be approached in terms of public installations and art and should be designed to accommodate and meet the needs of subway users appropriately. In order to find out what subway users think about environment shape objects in subway stations, the factors that can evaluate awareness and preference for environment shape objects and visual image of environment shape objects were examined and analyzed. Positive elements were shown with regard to environment shape objects a lot but it is judged that visual quality of subway environment can be deteriorated if environment shape objects do not harmonize with the characteristics of station environment.