This study aimed to assess the pollution level in 13 crowded subway stations in an effort to understand the spatial and seasonal factors of Indoor Air Quality. The main measured items were particulate pollutants such as PM10 and PM2.5 and gaseous pollutants such as CO2, HCHO, Rn, TVOC, BTEX, and Styrene at concourses and platforms in the summer and winter periods. The influence of the draught created by the movement of the train was classified into lateral and island platforms, and the concentrations of PM by location (entrance, middle, and end) were statistically compared and analyzed. As a result, the concentrations of PM were confirmed high in the order of Platform > Concourse > Ambient air. In particular, in the case of platform PM10, the frequency exceeding the standard value (100 μg/m3) was 38.5% and the maximum concentration was 196.2 μg/m3. All gaseous pollutants were at lower levels than the standard, and the factors affecting CO2 and Rn were identified as the number of users and geological characteristics, respectively. The principal component analysis (PCA) demonstrated that PM was found to be a major indicator of the air quality management of subway stations. In particular, the concentrations at entrance and end areas in the lateral platform were about 1.4 times higher with regard to PM10 than in the middle area, and about 1.9 times higher with regard to PM2.5 due to the effect created by the draught produced by the movement of the train. Therefore, in order to manage PM in the platform area, a specialized management plan for places with particularly high PM concentration within the platform area is required. In addition, it is necessary to evaluate the effect created by the draught produced by train movement when selecting locations for measuring indoor air quality.

To reduce subway passengers’ exposure to PM 10 (particulate matter less than 10 micrometers), management of PM 10 concentration in underground stations is critical. In this study, we attempted to investigate the distribution of airflow PM 10 concentration in an underground station. The numerical simulations were performed using computational fluid dynamics. In order to apply to CFD, measurement of air volume (supplied and exhausted air) and PM 10 concentration were conducted at the concourse and platform areas of the underground station. The results of the simulation agreed with the actual PM 10 concentration, and we confirmed the distribution of PM 10 concentration depending on air volume conditions. This result will be helpful to reduce the PM 10 in an underground station when using ventilation system.

Odor problems in urban areas have become a common cause of public complaints. In order to gain a better understanding of odor problems, we investigated the emission characteristics of odorants originating from manholes (n=22) and stormwater catch basins (n=48) (SCBs) around Wangsimni station in Seoul. To this end, concentrations of H2S and NH3 were measured after arbitrarily dividing the whole study area into five different districts. Our measurements were made to allow comparisons between three different criteria: (1) manholes vs. SCBs, (2) temporal variation between morning vs. afternoon, and (3) water content in the sewer system. The average concentration of H2S in manholes and SCB were 2.39 ppm and 0.81 ppm, respectively. In contrast, their NH3 counterparts were 1.86 ppm and 1.02 ppm, respectively. According to the contouring method made to identify spatial distribution characteristics, of odorants a relatively lowland site D was expected to work as a significant emission source in light of the transportation patterns of a sewer system. Moreover, higher concentrations of odorants were prevalent in the afternoon (as the prime time for commercial activities) relative to before noon. If concentration data are converted into odor intensity, H2S was the predominant component exerting controls on the odor pollution in these underground environments.

Most of the subway stations are located underground and the indoor air quality can be very poor. IAQ tele-monitoring systems (TMS) have been installed at some of subway stations in Seoul to monitor indoor contaminants, such as carbon dioxide, particulate matters and nitrogen oxides. In this paper, we use CO₂, PM₁₀, NO₂ concentration data collected by TMS in one of the underground stations in Line 4. The correlations are analyzed between the concentrations measured at different locations, such as tunnel, waiting room, and platform to identify the source characteristics. The results indicate there are very weak correlations between CO₂-NO₂ and PM₁₀-NO₂ but strong correlation between CO₂-PM₁₀, because both of PM₁₀ and CO₂ are related to the number of passengers. The comparison of PM₁₀ concentrations before and after the installation of platform screen door (PSD) indicates that considerable amount of particulate matters are entrained from tunnel into platform area. The PSD exhibits positive effects on indoor air quality especially on particulate concentrations. In case of NO₂, there is a strong correlation between indoor and outdoor concentrations. The results presented in this paper can be used to control indoor air quality in subway stations more effectively.

This study was conducted to investigate the response of the human body to stress induced by wall recording of subway stations in the city center. The experiment was conducted as a simulation exercise, and six images were selected and produced based on Subway Line 2, a representative underground space in Seoul. The study participants included 24 male and female college students. A three-minute experiment was conducted, during which the participants were shown the control image and green wall image once each. To measure psychological status, the following measurement indicators were used: Semantic Differential, Positive Affect and Negative Affect Schedule and State-Trait Anxiety Inventory. Physiological changes were investigated by tracking participants’ heart rate and blood pressure. Results showed that parasympathetic and sympathetic nerves were activated in the presence of the green wall in the subway station. The psychological evaluation analysis revealed that negative affect toward underground space decreased, while positive affect increased. This study found that the green wall in subway stations has a stable effect on the human body, both psychologically and physiologically. In the future, green walls in underground spaces can be used to reduce psychological stress and increase physiological relaxation.

We have identified the subway of structures as subway station users complained of vibrations from a structures when they walked through middle stairs of escalator. As a result of converting the vibration level to the conversion rate, it was measured at 3.846mm/s(82.7dB) on the B1st floor and 0.966mm/s(70.7dB) on the B2nd floor. These results are higher than the domestic standard of 65dB and lower than the international standard of under 5mm/s. It is felt well with the human body, but the structure is considered to be harmless. Therefore, it is deemded the structure is safe to usue. As the result of measuring the national frequency, the stairs on the B1st floor to be 3.01Hz and the stairs B2nd floor to be 5.36Hz. We consider that the users feel discomfort and anxiety on the B1st floor, where displacement and vibrations are higher.

Nonlinear dynamic analysis of Non-seismic Designed subway station was verified with Channel Beam Damper system which was developed in former research. As a result of nonlinear dynamic analysis, column and beam are on LS(Life Safety) level by retrofitting with Channel Beam Damper system. The effect of Channel Beam Damper System was confirmed.

지하역사의 대부분은 지진에 대비한 내진설계가 거의 수행되지 않음으로 인하여 일정규모 이상의 지진이 발생할 경우 대규모 인명 및 재산피해가 우려된다. 지중구조물인 지하역사의 신뢰도 높은 내진성능 평가를 위하여 지진하중 재하 시 지반과 구조물의 상호작용이 고려된 거동의 고찰과 검증이 요구된다. 이에 본 연구에서는 수도권 소재의 실제 지하역사에 대하여, 상사비 1/60 스케일의 축소모형 지하역사 구조물 시험체에 장주기인 Kobe지진파와 단주기인 Northridge지진파를 적용한 원심모형 진동대 시험을 수행하였다, 원심모형시험결과와 응답변위법, 동일단면에 대해 SHAKE91에 의한 지반 및 구조물의 상대변위, 구조물의 모멘트에 대하여 비교․분석함으로써 지하역사의 내진성능을 평가하고자 하였다.

본 연구는 생태공간과 생태공간으로부터의 거리에 따른 포름알데히드와 분진의 제거효과를 알아보기 위해 지하역사내로 자연광이 유입되는 천창이 설치된 지하철 흑석역에 조성된 생태공간을 바탕으로 수행하였다.그 결과, 1일 동안 생태공간, 생태공간으로부터 각각 10m, 20m떨어진 지점의 포름알데히드 농도는 약 20.7ppb, 21.2ppb, 26.8ppb로 생태공간과 생태공간에서 20m떨어진 지점을 비교하였을 때 생태공간이 공기를 정화하는 경향이 있는 것으로 보인다. 생태공간, 생태공간으로부터 10m, 20m떨어진 지점의 1일 분진 농도 역시 각각 약 18.0㎍/㎥, 19.2㎍/㎥, 67.4㎍/㎥로 생태공간과 생태공간에서 20m떨어진 지점을 비교하였을 때 생태공간의 공기정화효과를 알 수 있었다. 온도와 습도는 세 공간 모두 큰 변화가 없었는데 이는 지하역사내에 가동되고 있는 냉방 및 환기시설에 의한 것으로 보인다. 그러나 자연광의 유입으로 광합성과 증산작용이 활발하게 이루어지는 약 11시 30분부터 5시 30분까지는 생태공간의 습도가 약 3-4% 높게 나타났다. 또한 생태공간의 포름알데히드의 1일 변화량을 조사한 결과 이시간대에 포름알데히드 농도가 가장 낮게 나타났다. 따라서 지하공간에 조성된 생태공간은 포름알데히드, 분진을 감소시키고 습도를 증가시켜 실내공기를 쾌적하게 하는 것으로 보인다.또한 지하철 역사 간의 비교는 실공간에서 측정하므로 많은 변수들이 있기 때문에 비교가 불가능할 것으로 보이며, 앞으로 지하철 역사 내 생태공간의 공기정화효과를 입증하기 위해서는 지하철역사 간의 비교보다는 역사내에서 측정간격을 연장하거나 생태공간 유무에 따른 지상과 지하 등 측정장소를 달리하는 것이 필요하다고 판단된다. 따라서 지하철역사내 생태공간 조성은 포름알데히드, 분진 제거 등 공기정화와 미적․심리적인 효과를 동시에 창출하므로 앞으로 지하철 역사 및 지하공간내에 생태공간 조성이 확대되어야 할 것이다.

The personal exposures of nitrogen dioxide(NO2), microenvironmental levels and daily time activity patterns on Seoul subway station workers were measured from February 10 to March 12, 1999. Personal NO2 exposure for 24 hours were 29.40±9.75 ppb. NO2 level of occupational environment were 27.87±7.15 ppb in office, 33.60±8.64 ppb in platform and 50.13±13.04 ppb in outdoor. Personal exposure time of subway station workers was constituted as survey results with 7.94±3.00 hours in office, 2.82±1.63 hours in platform and 1 hours in outdoor. With above results, personal NO2 exposure distributions on subway station workers in Seoul were estimated with Monte Carlo simulation which uses statistical probabilistic theory on various exposure scenario testing. Some of distributions which did not have any formal patterns were assumed as custom distribution type. Estimated personal occupational NO2 exposure using time weighted average (TWA) model was 31.29±5.57 ppb, which were under Annual Ambient Standard (50 ppb) of Korea. Though arithmetic means of measured personal NO2 exposure was lower than that of occupational NO2 exposure estimated by TWA model, considering probability distribution type simulated, probability distribution of measured personal NO2 exposures for 24 hours was over ambient standard with 3.23%, which was higher than those of occupational exposure (0.02%). Further research is needed for reducing these 24 hour NO2 personal excess exposures besides occupational exposure on subway station workers in Seoul.