• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.5
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• pp.1-9
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• 2005

This study was conducted to investigate the effect of aquatic plant as a botanical air purification on the indoor air pollution by formaldehyde. Three aquatic plants such as Eichhornia crassipes, Cyperus alternifolius, Echinodorus cordifolius, were selected for this study and they were placed in the artificially contaminated chamber under laboratory condition. The results showed that all three plants could remove the formaldehyde from the contaminated air system effectively. Reduction in the formaldehyde levels by Eichhornia crassipes, which is the floating plant, might be associated with the factors of plant and water. Reduction in the formaldehyde levels by Cyperus helferi and Echinodorus cordifolius, which were emergent plant, was due to the complex effect of plant, soil medium and water. In aquatic plant system, dissolution, microbial degradation in rhizosphere, uptake through root and shoot, sorption to soil and shoot, hydrolysis are known as the main mechanisms of water soluble pollutants in the given system. The advantages of indoor air quality control system using aquatic plants can be; 1) various purifying mechanisms than foliage plants, 2) effective for decontamination of water soluble pollutants; 3) easy for maintenance; 4) diverse application potential. Therefore it was suggested from the results that indoor air control system of aquatic plants should be more effective for reduction of indoor air pollutants.

• Journal of Environmental Health Sciences
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• v.48 no.1
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• pp.44-51
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• 2022

Background: Air pollution is increasing together with industrialization and urbanization. In order to reduce air pollution, public transportation is recommended rather than private cars, and the number of passengers using public transportation is increasing accordingly. This study observes the concentration of indoor pollutants in city buses over time. Through this means, we intend to suggest a plan to manage the indoor air quality in city buses. Objectives: The concentration of indoor pollution in public transportation was investigated from April 2021 to January 2022. Based on this, we evaluated the exposure to indoor pollutants. Methods: Six city bus lines in an industrial city were selected for the research, and indoor pollution was measured through IoT (Internet of Things)-based sensor-type measuring devices. The concentration of pollutants was measured every minute, and statistical data were constructed based on the measurement results. Results: In all the city buses studied, the average concentration of pollutants were below the guidelines. However, some measurement results showed cases of exceeding the guidelines. As a result of the analysis by time zone, there were more cases in which pollutants exceeded the standard value during rush hour compared to at other times. A risk assessment for PM₁₀ was performed by evaluating the excess mortality risk from exposure and the risk from inhalation exposure. Conclusions: All measured indoor pollutants in the city buses did not exceed the guidelines. Also, the risk assessment results were found to be within the level of safety. However, if a city bus is used for a long time, there is a possibility that there may be an impact on the human body due to inhalation exposure, so additional management is required.

• Journal of the Korean housing association
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• v.21 no.6
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• pp.11-18
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• 2010

The aims of this study were to grasp the real condition state and clarify the characteristics and influence of pollutants on the indoor air pollution in occupied apartment units. The research method was to measure the pollution levels of indoor air pollution, and investigate characteristics of the pollutants such as the outdoor environment, elapsed time after construction, finished materials, temperature, relative humidity, space extension, purchase with furniture and electric appliances, built-in closets, and method for cleaning the air. And these were made a comparition between industrial and residential area. The VOCs and formaldehyde concentration in indoor air were measured the 6 household in residental area and 5 household in industrial area. In conclusion, the concentration such as benzene, ethylbenzene, toluene, xylene, styrene showed the pollution state within permissible levels, however formaldehyde concentration has need a lot of attention as ever. And it turned out that the influence with reference to emission from building materials on indoor air pollution lessened under 18 months elapsed time after construction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.29-30
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• 2019

The indoor air quality of modern people who work indoors more than 80 percent a day has also become a very important factor in their lives. But most indoor air quality is highly polluted due to energy conservation and lack of ventilation. This can lead to pneumonia, asthma and even lung cancer, which can be fatal to children, the elderly and the elderly. Indoor pollutants are caused by boards, wallpaper, paint, etc. used in interior By producing indoor finishing materials using active alumina gel, which is used as dehumidifier, indoor pollutants will be reduced and the possibility of developing respiratory diseases and lung cancer will be reduced.

• 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.

• Journal of Environmental Health Sciences
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• v.20 no.1
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• pp.28-38
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• 1994

The objective of this study were to measure concentrations of indoor pollutants in public transportation systems to provide importance of indoor air quality in transportation systems to policy makers. Indoor air quality of the pollutants (CO, CO$_2$, PM-10) and environmental sources (temperature, humidity) were measured at subway, seat-type bus, and city-type bus in the Seoul area from April to September 1992. The same pollutants and environmental sources were also measured at selected bus stops and subway stations during October 1991-September 1992. The mean concentrations of indoor pollutants in the public transportation systems were showed 115.5 $\mu$g/m$^3$ in PM-10, 6.8 ppm in CO, and 2167.9 ppm in CO$_2$, respectively. The mean values of PM-10 and CO showed below the U.S. 24 hour standard value of PM-10 and the Korea ambient CO standard, while the mean concentrations of CO$_2$ exceeded the Korea CO$_2$ standard. The highest levels of indoor concentration at public transportation systems were PM-10 of 134.6 $\mu$g/m$^3$ in the subway, CO of 8.9 ppm in the city-type bus, CO$_2$ of 2,511.1ppm in seat-type bus, respectively. The results showed that indoor air quality in bus and subway seemed likely to be affected by number of passengers and outdoor air infiltrated from exhausted gases of automobiles.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.4
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• pp.343-360
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• 1998

In this study, comprehensive air quality monitoring was undertaken with a variety of objectives to collect data on the levels of various indoor and ambient air quality parameters in the urban areas of Seoul and Taegu. The sampling sites were comprised of six offices, six residences and six restaurants in each city. The ambient air adjacent to the indoor sites was also simultaneously sampled for the same constituents. The sampling was conducted in two phases: summer of 1994 and winter of 1994/95. A range of air quality parameters were measured simultaneously, which include RSP, CO, COB, NOB, a range of VOC, airborne microbials, temperature, and relative humidity. The indoor and ambient levels of the pollutants measured in this study varied widely between the three types of environments studied. Comparison of median values for the three groups revealed that restaurants had higher indoor levels of most pollutants than homes or offices. There was also a clear pattern of the indoor levels of target pollutants being higher than those outdoors, particularly in restaurants. Concentrations of CO and most of the VOC were found to be significantly higher in the commercial districts, indicating the influence of vehicle exhaust emissions. A very wide range of VOC levels was documented in this study. Although median indoorloutdoor ratios indicated a generally increasing level of VOC indoors when compared to those outdoors, no statistically significant differences were found between indoor and outdoor VOC levels in homes and offices, implying the importance of ambient air quality in determining the quality of indoor air for homes and offices in urban areas. In addition, there was a general pattern of increasing concentrations from summer to winter, and similarly from outdoor to indoor air for nearly all target compounds. The seasonal differences in median levels were very clearly seen for fuel combustion related pollutants such as RSP, CO and VOC, this being attributed to the effects of increased fuel consumption during the cold season and to meteorological factors.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.275-281
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• 2006

Indoor air quality is the dominant contributor to total personal exposure because most people spend a majority of their time indoors. Especially exposure to indoor air can potentially pose a greater threat than exposure to ambient air when indoor environments have sources of contaminants. In this study, volatile organic compounds (VOCs) and formaldehyde (HCHO) within newly constructed apartment have been determined in 27 houses of apartment in Seoul from December 2004 to March 2005. The measured indoor air pollutants were HCHO, volatile organic compounds including benzene, toluene, styrene, xylene, ethylbenzene and sampled on the standard method of Ministry of Environment in Korea. The indoor levels for benzene, xylene, toluene, ethylbenzene, styrene, and HCHO have significant increase trend after 5 hours closing of windows and doors. Levels of measured air pollutants concentrations between living rooms and bedrooms have not shown significant difference. Spearman correlation coefficient among the measured air pollutants ranged from 0.303 to 0.946, indicating similar source in building materials.

• Journal of environmental and Sanitary engineering
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• v.23 no.2
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• pp.35-45
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• 2008

In order to recommend criteria for the administration law on indoor air quality, this study was conducted to examine the distribution and the concentration of indoor air pollutants ($PM_{10},\;CO_2$, CO, HCHO, TBC, $NO_2$, Rn, VOCs, asbestos, $O_3$) in public facilities in the Chung-Nam area. The concentrations of indoor air pollutants were obtained from sixty seven public facilities such as a cinema, an office, a restaurant, a theater and an academy. This study was performed from August to December, 2005. The results of this study showed that the concentrations of indoor air pollutants such as $PM_{10},\;CO_2$, CO, HCHO, TBC, Rn and $O_3$ were less than the recommended limits. However, the average concentration of VOCs was $521.73{\mu}g/m^3$ (GM : $221.69{\mu}g/m^3$), which was higher than the recommended limit of $400{\mu}g/m^3$. Moreover, the average concentration of $NO_2$ was 345.66ppb (GM : 69.95ppb), which was higher than the recommended limit of 50 ppb. The correlation between the concentrations of indoor air pollutants and the type of facilities with respect to $CO_2$, TBC and Rn was statistically low (p<0.05). However, the correlation was high in terms of the CO and $O_3$ concentrations (p<0.01). No relationship between the indoor air pollutants and the type of facilities was observed for $PM_{10}$, VOCs and $NO_2$. The year of construction was compared to the concentrations of indoor air pollutants. Specifically, when the construction date was less than 3 years, the HCHO, VOCs and TBC concentrations were $44.75{\mu}g/m^3,\;555.07{\mu}g/m^3$ and $337.79CFU/m^3$, respectively. These concentrations were $120{\mu}g/m^3$ and $211.84CFU/m^3$ higher for VOCs and TBC than the concentrations obtained from the facilities more than 3 years. However, the concentration of HCHO was similar between the facilities older and younger than 3 years of age. Year, temperature, humidity and indoor air pollutant correlation analyses showed that temperature and humidity, temperature and TBC, temperature and $O_3,\;PM_{10}$ and $NO_2$, HCHO and VOCs, $CO_2$ and Rn had positive relationships. However temperature and Rn, humidity and $CO_2,\;CO_2$ and $O_3,\;O_3$ and Rn had negative relationships. Accordingly, it will be necessary to manage the factors affecting indoor air quality so that the residents can have a more comfortable and healthier living environment. Ultimately, the results of this study are expected to be utilized as baseline data.

• Journal of Environmental Science International
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• v.15 no.10
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• pp.913-918
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• 2006

Despite the wide distribution of air pollutants, the concentrations of indoor air pollutants may be the dominant risk factor in personal exposure due to the fact that most people spend an average of 80% of their time in enclosed buildings. Researches for improvement of indoor air quality have been developed such as installation of air cleaning device, ventilation system, titanium dioxide$(TiO_2)$ coating and so on. However, it is difficult to evaluate the magnitude of improvement of indoor air quality in field study because indoor air quality can be affected by source generation, outdoor air level, ventilation, decay by reaction, temperature, humidity, mixing condition and so on. In this study, evaluation of reduction of formaldehyde and nitrogen dioxide emission rate in indoor environments by $TiO_2$ coating material was carried out using mass balance model in indoor environment. we proposed the evaluation method of magnitude of improvement in indoor air quality, considering outdoor level and ventilation. Since simple indoor concentration measurements could not properly evaluate the indoor air quality, outdoor level and ventilation should be considered when evaluate the indoor net quality.