• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1581-1587
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• 2006

Today's subway system is packed with various informations such as danger/safety signs, directions, and tightly placed advertisements. All these elements are becoming one big chaos rather than convenient source of information for commuters. To solve this problem immediately, it has to be analysed for systematic character of subway spaces and leaded to constructive improvement for the locating subway signs in correct and convenient spots with right contents. Especially in case of transfer stations, structure is complicated and mazed. At the same time, tremendous amount of commuters are passing through and all these commuting are adding more complications and chaos to the system. Therefore, it is harder to focus on gathering environment informations and finding right directions. Better guiding signage for easier transfer is now essential for new standard of modern commuting with total and logical system. Eventually, it will be great help for setting budget efficiency and advanced subway environment through efficient and Koreanized subway transfer system.

• 한국대기환경학회지
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• 제30권2호
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• pp.175-187
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• 2014

The subways play an important part in serious traffic problems. Almost seven million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan city in 2012. However, the subway system is a semi-closed environment, so many serious problems occurred in subway stations and injured passengers' health. Platform screen doors (PSD) are expected to prevent negligent accident such as injury or death from falling and improve the air quality of the subway station. Installation of PSD at stations in Seoul metropolitan subway had been completed in December 2009. Consequently, the underground transportation system became a closed environment, so the air quality has improved the platforms, but it has deteriorated in the tunnels. Especially, the subway cabin has many doors, and the doors are frequently opened and closed. For this reason, the effect of door opening on subway cabin, dust flow inside the subway cabin. In this process, the maintenance work may influence the health of people who work underground, as well as that of subway users (passengers). In this study, we measured air quality inside and outside of the subway cabin line 2 in Seoul, Korea. This study focused on the investigation of Indoor Air Quality (IAQ) and measurement target pollutants are PM10, CO, $CO_2$, $NO_2$, $O_3$. It was found that levels of PM10, $CO_2$, and $NO_2$ inside subway cabin line 2 exceeded the Korea IAQ standard. Concentrations of PM10, $CO_2$, and $NO_2$ inside of the cabin are higher than outside of the cabin (Indoor Outdoor ratio is higher than 1.). Concentrations of CO, $O_3$ inside of the cabin are lower than outside of the cabin (Indoor Outdoor ratio is lower than 1.). There is a high correlation between $CO_2$ and passengers inside of the cabin and PM10 is only the weakest correlation with passengers. Therefore, it is important to find out the emission source of $NO_2$. The results of this study will be useful as fundamental data to study indoor air quality of a subway cabin.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2003년도 추계학술논문발표회논문집
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• pp.318-325
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• 2003

• 한국대기환경학회지
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• 제32권2호
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• pp.216-232
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• 2016

In present, the Seoul City is undergoing traffic congestion problems caused by rapid urbanization and population growth. Thus the City government has reorganized the mass transportation system since 2004 and the subway has become a very important means for public transit. Since the subway system is typically a closed environment, the indoor air quality issues have often raised by the public. Especially since a huge amount of PM (particulate matter) is emitted from ground tunnels passing through the subway train, it is now necessary to assess the characteristics and behaviors of fine PM inside the tunnel. In this study, the concentration patterns of $PM_1$, $PM_{2.5}$, and $PM_{10}$ in the Seoul subway line-2 were analyzed by real-time measurement during winter (Jan 13, 2015) and summer (Aug 7, 2015). The line-2 consisting of 51 stations is the most busy circular line in Seoul having the railway of 60.2 km length. The the one-day average $PM_{10}$ concentrations were $148{\mu}g/m^3$ in winter and $66.3{\mu}g/m^3$ in summer and $PM_{2.5}$ concentrations were $118{\mu}g/m^3$ and $58.5{\mu}g/m^3$, respectively. The $PM_{2.5}/PM_{10}$ ratio in the underground tunnel was lower than the outdoor ratio and also the ratio in summer is higher than in winter. Further the study examined structural types of underground subsections to explain the patterns of elevated PM concentrations in the line-2. The subsections showing high PM concentration have longer track, shorter curvature radius, and farther from the outdoor stations. We also estimated the outdoor PM concentrations near each station by a spatial statistical analysis using the $PM_{10}$ data obtained from the 40 Seoul Monitoring Sites, and further we calculated $PM_{2.5}/PM_{10}$ and $PM_1/PM_{10}$ mass ratios near the outdoor subway stations by using our observed outdoor $PM_1$, $PM_{2.5}$, and $PM_{10}$ data. Finally, we could develop pollution maps for outdoor $PM_1$ and $PM_{2.5}$ near the line-2 by using the kriging method in spatial analysis. This methodology may help to utilize existing $PM_{10}$ database when managing and control fine particle problems in Korea.

• 한국환경보건학회지
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• 제47권5호
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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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1475-1480
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• 2007

Numerical analysis has been conducted to simulate pedestrian flow in the model of two-storied subway station. Because almost all the subway stations are two or three storied structure, simulations are conducted for the passengers those who get off the train and pass the wicket. Passenger flow analysis is very important factor to design the station and also to manage the operation of subway system. In the subway station, pedestrians move to the horizontal directions as well as vertical ones. Therefore, to consider the movement of pedestrians is necessary for the guarantee of safety and conveniency. As the up and down floors are connected with step, escalator and elevator, the entire movements in the multi-storied station should be simulated as like a 3-dimensional flow. Numerical schemes for the directional sweeping are developed to prevent the dependency on physical structure of station and to determine primary direction and secondary one. By using the developed program, we compared the simulation results of the effects of the location and size of exit and elapsed time.

• 한국안전학회지
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• 제25권6호
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• pp.123-127
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• 2010

A fire disaster is very serious in the closing space like subway station. In this study, the simulation on fire diffusion is performed to get the temperature history curve, which is used for the fire resisting structural analysis. Most of subway stations are built by the reinforced concrete structure, but recently steel structures are selected for the larger space or beauty. Steel structures relatively have more weaknesses against fire, so it is necessary to develop the method for evaluating fire-resisting capacity in this kind of structures. The developed method is applied to the subway station in Daegu city. It shows that the developed method can be used to simulate the fire disaster and to get the temperature history curve and evaluate the safety of steel structures against the fire.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1138-1142
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• 2005

The IAQ management in subway cabin is very important for the enhancement of the amenity and health of passengers because the subway carries many passengers in a relatively short time mostly in urban area. However, since the ventilation of most subway cabins are performed by simple opening of doors at each stations, the IAQ management is not easy. In this study, we measured some IAQ factors (temperature, relative humidity, particulate matters, CO, and $CO_2$ concentration) of subway cabin in Seoul area. The results showed that the IAQ of the cabin was relatively acceptable. However, $CO_2$ concentrations were higher than 1,000 ppm in most cases. $CO_2$ concentration was mostly proportional to the number of passengers in cabin. Therefore, new method to relieve the $CO_2$ concentration is urgently required.

• 한국철도학회논문집
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• 제3권2호
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• pp.62-67
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• 2000

Modern people stay at indoor places about 90% of a day. Radon-222 is a gas produced by the radioactive decay of the element radium. And, radon is one of the major indoor air pollutants. Radon moves into the underground space through various routes and is considered to cause lung cancer by hurting the lung tissues. In this study, we measured the subway radon level at 9 stations of 3 lines. According to test results, we can figure out the concentration of radon by lines, times, and measuring points. So, it was found that ventilation conditions are the most important factors in the subway air quality. Finally, we suggested effective and economic management methods of air pollution in the subway.

• 한국IT서비스학회지
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• 제17권4호
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• pp.139-150
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• 2018

This paper investigated the human distribution in subway station areas in Seoul, using geotweets and subway ridership data. Eight stations were selected from the districts of Gangnam and Gangbuk. Geotweets located within a 600-meter radius of the central coordinates of each station were extracted, and distances between the center of station and each tweet location were calculated. Donut-shaped dimension and pie-shaped dimension were generated, using the Haversine distance formula and the Azimuth angle formula respectively. By combining the two dimensions, Dartboard-shaped space division is created. Popular places within the subway station areas identified from this research are almost the same as the current well-known popular places, and this is an important case showing that people send tweets from various places where they engage in daily activities. We expect this study can be a methodological guideline for social scientists who use spatio-temporal or GPS data for their research.