• Proceedings of the KSR Conference
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• 2009.05a
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• pp.919-929
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• 2009

2008, Seoulmetro transports an average of 3,952,000 passengers every day with a 0.8% increase of the daily ridership compared to last year.(Korean Economics '09.01.21) Seoul subway systems ridden by a considerable number of Seoul citizens place their top priority on swiftness, safety and clean underground air quality so as to meet the customer satisfaction. One of the most important problems is to eliminate minute dust(PM10) among the pollutants such as the gas attributable to air pollution and floating particulate matter defined by the ordinance of the Ministry of Environment. Seoulmetro install and operate many kinds of air filtration facilities, however we've launched a research on "Standardization Plan on Underground Air Filtration Facility" for the installation and improvement of optimum standardized air filtration system. As a preliminary study, we're going to consider ventilation system and air filter to supply filtered metropolitan outdoor air aimed at ensuring clean underground environment.

• Journal of Environmental Health Sciences
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• v.33 no.4
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• pp.255-263
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• 2007

Indoor air quality is the dominant contributor to total personal exposure because most people spend a majority of their time indoors. The purposes of this study were to evaluate the alternative method for improvement of indoor air quality in house after coating titanium dioxide ($TiO_2$) photocatalyst for interior part of the house using nitrogen dioxide ($NO_2$) multiple measurements. To evaluate the alternative method in indoor environment, daily indoor and outdoor $NO_2$ concentrations of an apartment and a detached house were daily measured for consecutive 21 days in winter and summer, respectively, Another daily 21 measurements were carried out after $TiO_2$ coating on wall paper of interior part in houses. All $NO_2$ concentrations were measured by passive filter badges. Indoor air quality models using mass balance are useful tool to quantify the relationship between indoor air pollution levels, ambient concentrations, and explanatory variables. Using a mass balance model and linear regression analysis, penetration factor (ventilation rate divided by sum of ventilation rate and decay rate) and source strength factor (emission rate divided by sum of ventilation rate and decay rate) were calculated. Subsequently, the decay constants were estimated. In this study. magnitude of improvement of indoor air quality could be evaluated by decay constant.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.5
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• pp.569-579
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• 2011

This study evaluated the indoor air quality of 26 government offices located in Seoul. The pollutant samples were taken from Jan. 13th to Jan. 29th and Feb. 20th to Feb. 23rd, 2010 in the offices. The target indoor pollutants for this study were $PM_{10}$, formaldehyde, carbon monoxide, carbon dioxide, total bacteria counts, total volatile organic compounds, radon, nitrogen dioxide, ozone, and asbestos which were controlled by the indoor air quality law for the multiple-use facilities management. The results of this study showed that some pollutants of the 38.5% offices exceeded the standards of the air quality guideline. The correlation analysis of the same pollutants between indoor and outdoor represented that $NO_2$ (r=0.629, p<0.05) and $O_3$ (r=0.459, p<0.01) were significant, however, $PM_{10}$ and CO were not. The correlation analysis between different pollutants showed that CO and TVOC (total volatile organic compounds: r=0.724; p<0.01), CO and $NO_2$ (r=0.674; p<0.01), HCHO and humidity (r=0.605; p<0.01), $CO_2$ and TVOC (r=0.534; p<0.01), TBC (total bacteria counts) and Asbestos (r=0.520; p<0.01) were significant. The energy-saving system of government buildings in winter caused under-ventilated and poor air quality. This study suggests that the concentrations of radon and $CO_2$ should be used as an indicator for monitoring indoor air quality and maintaining effective ventilations.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1652-1655
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• 2008

Indoor air quality (IAQ) of subway becomes a key issue as the IAQ guidelines for public transportation published. There are two major sources regarding IAQ of subway; One is the sources coming from outdoor air and the other is sources of inside. Particulate matters smaller than 10 micrometer (PM10) and carbon dioxide ($CO_2$) are recognized as the one of the most severe pollutants in Korea. The source of PM10 is mainly coming from outdoor air, however, the source of $CO_2$ is coming from passengers exhaust. According to the guidelines, the level of $CO_2$ should be lower than 2500ppm for normal operating time and lower than 3500ppm for rush hour. In order to satisfy these guidelines, the volume of mechanical ventilation should be increase which consumes extra energy for heating or cooling. Therefore, the optimum volume of mechanical ventilation should be calculated for energy saving. In this study, we measured the natural ventilation rate by door-opening which can reduce the load of mechanical ventilation. The $CO_2$ generator and sensors were used to measure the change of $CO_2$ by periodic door-opening of subway.

• Asian Journal of Atmospheric Environment
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• v.4 no.3
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• pp.157-165
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• 2010

The purpose of this study is to investigate allergic diseases related to allergy caused by the exposure to indoor and outdoor sources of air pollution in primary schools. The symptoms questionnaire of allergic diseases based on the International Study of Asthma and Allergies in Childhood (ISAAC) was completed by the participants. The past and present status of asthma, allergic rhinitis, eczema, and allergic conjunctivitis were investigated by providing a questionnaire to all the participating children. Questionnaires were sent to a total of 61,350 children from 438 primary schools. A total of 40,522 children responded to the questionnaire, which represents a 66.1% return rate. Volatile Organic Compounds (VOCs), $\underline{A}$ldehydes, and Particulate Matter ($PM_{10}$) were measured and analyzed from October to December of 2006, in 82 primary schools. The final study population comprised 35,168 children with complete data which excluded incomplete questionnaire responded by 5,354 children. Based on the survey, the level of indoor air contamination did not appear to be high, but 27.2% of the schools evaluated had exceeded the $PM_{10}$ level specified by the school health guidelines ($100\;{\mu}g/m^3$). The overall mean concentration of formaldehyde was $22.07\;{\mu}g/m^3$ and 1.0% of schools (1 school) exceeded the $100\;{\mu}g/m^3$. Statistically significant relationships have been observed between indoor air quality and prevalence rate of allergic rhinitis and conjunctivitis of primary schools in Korea.

• Korean Institute of Interior Design Journal
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• v.18 no.4
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• pp.79-87
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• 2009

Residential Buildings should provide high-quality, comfortable environments to support the activities of their occupants. The indoor environment of residential buildings, which includes thermal, lighting, acoustic, and indoor air quality, has a significant impact on health and quality of life. The comfortable living environment in residential buildings result from appropriately combining these environmental quality factors, and the performance of building systems must be compatible with the activities of the occupants. The objective of this research is to investigate and analyze the relationship between physical environmental conditions and occupant responses for improving environmental quality (EQ) in apartment buildings with four different building orientations (i.e. E, W, S, N) in two different seasons (i.e. winter and summer). The occupant survey was conducted in actual apartment buildings. The Physical environmental conditions in apartment buildings differed substantially depending on space, outdoor weather conditions and building orientations. Each space within the same apartment building had different environmental conditions. Combinations of unbalanced physical environmental conditions in apartment building decrease occupants' satisfactions and their perceptions of overall residential quality. Occupants' satisfaction and their responses to physical characteristics of their residential environment is related to thermal, lighting, acoustic, and indoor air conditions in their buildings. The result from this research will help designers and researchers to identify problems and develop solutions for improving environmental quality from the occupants' point of view.

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.41-48
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• 2003

Most of people spends their times in indoor about 85% of a day. Thus, indoor is more serious than outdoor concerned with the health. We discussed comfortableness in a railroad electric rolling stock, and focused on temperature and humidity. Electric rolling stock is one of major public transportation system because of an increasing in population and heavy traffic problems. The passengers are under the influence of indoor air quality such as air temperature, relative humidity and air velocity. Ventilation system in electric rolling stock should be designed for the health and comfort. One of the main aims is to create an acceptable thermal environment without draught problem. The draught sensation increases when the air temperature decreases and the air velocity increases. Airflow in electric rolling stork is turbulent. Temperature and humidity gradients in electric rolling stock have been studied. And, the difference between mean temperature and rotative humidity measured at 0.7, 0.9, 1.2, 1.7m above the floor. It has been found that temperature and relative humidity with large fluctuations caused more draught complaints.

• Journal of Environmental Health Sciences
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• v.43 no.1
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• pp.71-76
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• 2017

Objectives: This study aimed to assess the environmental factors that affect particulate matters (PM10) and to compare with outdoor PM10 concentrations in an underground subway stations. Methods: The PM10 level was determined from May 2013 to September 2013 in the Seoul subway stations in four lines. PM mini-vol portable sampler sampler was used to collect PM10 for 6 hrs. Arithmetic means of PM10 concentrations with standard deviation (SD) were calculated. Paired t-test was used to compare the differences between indoor PM10 and outdoor PM10 concentrations with correlation analysis which was used to identify the association between indoor PM10 concentrations and environmental factors. Results: There were no different PM10 concentrations significantly between line 1, 2, 3 and 4 in an underground subway stations. Passenger number was positively associated with PM10 concentration while construction year was negatively associated with PM10 concentrations. Indoor PM10 concentrations were significantly higher than those in outdoor PM10 concentrations. PM10 concentrations were higher in the stations which were constructed before 1990s rather than the stations constructed after 1990s. Conclusion: PM10 levels in the underground subway stations varied greatly depending on the construction year. Therefore, it might need to be more careful management to the stations which constructed in before 1990s.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.372-378
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• 2007

This study evaluated formaldehyde concentration in classrooms and on roofs at 4 elementary schools, 3 middle schools and 3 high schools in Incheon City. These schools were chosen based on their surrounding environments that included industrial site, landfill, railway, 8-lane road and harbor. Indoor concentration ranged between 4.65 and $56.25{\mu}g/m^3$, while that of outdoor concentration was $1.23{\sim}10.22{\mu}g/m^3$, both of which were below $100{\mu}g/m^3$, a formaldehyde criterion stipulated by the School Health Act. Indoor concentration was higher than outdoor concentration by $1.4{\sim}5.9$ times, and there was a positive correlation between indoor and outdoor formaldehyde concentrations (R=0.49). As for indoor concentration, multi-use practice rooms had an average 2.8 times higher than that of usual classrooms with a statistically significant difference (p<0.01). Indoor formaldehyde concentration had a positive correlation with the construction year (R=0.55). The school close to the industrial complex had the highest ambient formaldehyde concentration, followed by the one near a landfill. The formaldehyde concentration in school in the vicinity of the industrial complex was twice or more than that of the school located other site. In conclusion, this study suggests that it is crucial to consider surrounding environments in selecting school sites, as it can influence ambient air contamination, as well as using construction material that emit less formaldehyde, in order to protect the health of students, teachers and school staff.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.92-97
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• 2004

Three methods for VOCs emissions control in indoor air are reduction at the source, ventilation between indoor and outdoor, and removal. The best alternative should be to replace highly emitting sources with sources having low emissions, but the pertinent information on VOCs is not always available from manufactures. Other ways of improving indoor air quality are needed. It is to increase the outside fresh-air flow to dilute the pollutants, but this method would generally provide only a dilution effect without destruction in residence. An ideal alternative to existing technologies would be a chemical oxidation process able to treat large volumes of slightly contaminated air at normal temperature without additional oxidant such as ozone generator and ion generator. Photocatalytic oxidation(PCO) represents such a process. It is characterized by a surface reaction assisted by light radiation inducing the formation of superoxide, hydroperoxide anions, or hydroxyl radicals, which are powerful oxidants. In comparison with other VOCs removal methods, PCO offers several advantages. The purpose of this study was to explore the possibilities for photocatalytic purification of slightly contaminated indoor air by using visible light such as flurescent visible light(FVL). In this study, a PCO of relatively concentrated benzene using common FVL lamps was investigated as batch type and total volatile organic compounds(TVOCs) using a common FVL lamp and penetrated sun light over window. The results of this study shown the possibility of TiO$_2$ photocatalyst application in the area of indoor air quality control.