• Journal of Environmental Science International
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• v.24 no.10
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• pp.1273-1283
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• 2015

In present study, the temporal characteristics of nine selected volatile organic compounds (VOCs), including four alcohol, 2 aldehyde, and 3 ketone compounds, in high-stories urban apartments over a 2-y period were investigated. The indoor VOC concentrations had generally a decreasing trend over the 2-y follow-up period. For examples, the 2E1H indoor concentration decreased from $10.8{\mu}g/m^3$ for the first two months to $5.1{\mu}g/m^3$ for the last two months. In addition, the DCA and ACT indoor concentrations decreased from 5.0 and $14{\mu}g/m^3$ for the first two months to 2.2 and $6.4{\mu}g/m^3$, respectively, for the last two months. The indoor-to outdoor concentration ratios over the 2-y period were much greater than 1, indicating that indoor VOC concentrations were higher than the outdoor VOC concentrations. Similar to those of the individual VOCs, the indoor-to-outdoor concentration ratios of all three VOC groups were higher than 1 over the 2-y follow-up period, suggesting higher indoor concentrations of the three VOC groups than outdoor concentrations. In consistence with the results of VOC indoor concentrations, the VOC emission rates decreased gradually as time passed, due to the decreased VOC emission strengths of indoor sources. Finally, there was an initial sharp decrease in the indoor VOC concentrations followed by a slower decrease, indicating a multi-exponential decay model for the target VOCs, which was demonstrated by comparison of the residuals and the adjusted coefficient of determination associated with the one and two-exponential fits of each data set.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.3
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• pp.325-337
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• 2014

The research on the actual condition of indoor asbestos concentration in Korea has not been thoroughly accomplished up to now. In this research the ratio of asbestos-containing buildings and indoor asbestos concentration was studied. This investigation was conducted in 2012 and 2013 and buildings were categorized based on region, building type by use, existing space(ground or basement), and construction year, respectively. Also the indoor asbestos concentration change was monitored to evaluation the efficiencies of two types of asbestos-concentration abatement devices. As a result, the ratio of asbestos-containing buildings in Seoul was largely decreased. The ratio of asbestos-containing buildings was higher in hospitals and schools regionally and in ground buildings than in basement. The average indoor asbestos concentrations were 0.0011, 0.0008 piece/cc in 2012 and 2013 investigation, respectively. Those values were much lower than standards(0.01 piece/cc), therefore the threat of indoor asbestos concentration might be negligible. In asbestos-concentration abatement experiments, the circulation velocity of ventilator were changed 2-6.7 m/sec. With 6.7 m/sec of velocity of ventilator, the concentration of indoor asbestos was fluctuated and maximum value was 2.4 piece/cc. With 4.5 and 2 m/sec of velocities of ventilator, the maximum concentration of indoor asbestos was fluctuated and maximum value was 0.9 piece/cc. This indicated that the concentration of indoor asbestos was decreased partly due to the free drop of asbestos. From these results, the proper velocity of ventilator seems to be between 4.7 and 6.5m/sec under this circumstance and further research is required. These research results may be used to guideline of asbestos management policy.

• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.421-432
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• 2018

Objectives: In this study, we started to develop an indoor garden integrated IoT solution based on IAQ (indoor air quality) and interconnection with an environmental database for smart management of indoor gardens. The purpose of this study was to develop and apply an integrated solution for customized air purification from an indoor garden through big data analysis using IoT technology. Methods: An IoT-based IAQ monitoring system was established in three households within a new apartment building. Based on real-time and long-term data collected, $PM_{2.5}$, $CO_2$, temperature, and humidity changes were compared to those of indoor garden applications and the analyzed results were indexed. Results As a result of the installation, all three households had no results exceeding the standard for indoor air pollution on average $PM_{2.5}$ and $CO_2$ indices. In the case of indoor garden installation, the IAQ index increased to the "Good" section after the installation, and readings in the "Bad" section shown before the installation disappeared. The comfort index also did not dip into the "Uncomfortable" section, where it had been preinstallation, and significantly lowered the average score from "Uncomfortable for sensitive groups" to "Good". Overall, the IAQ composite index for the generation of installations decreased the "Good" interval, but "Bad" did not appear. Conclusions In this study on developing an integrated solution for IAQ based on IoT indoor gardens, big data was analyzed to determine IAQ and comfort indexes and an IAQ composite index. Through this process, it became understood that it is necessary to monitor IAQ based on IoT.

• 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.

• Asian Journal of Atmospheric Environment
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• v.9 no.1
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• pp.31-38
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• 2015

Due to the heightened ambient $PM_{2.5}$ levels, the whole citizen of Japan, especially dwellers in Fukuoka Prefecture, start to make attention to the particulate matter (PM) of indoor environments. This study was aimed to thoroughly estimate the characteristics of indoor PM collected in five Japanese homes located in Fukuoka Prefecture. Simultaneous indoor measurements of PM were intensively made at five homes using filter-pack samplers, particle counters, and $PM_{2.5}$ monitors for a day in springtime, 2012. Major ionic and carbonaceous components were also analyzed. The time series fluctuation of PM number concentration was gradually decreased by 6 AM and then it was rapidly increased by 8 AM in all indoor sites. The maximum level of $PM_{2.5}$ was measured at the morning time (8 AM-9 AM) when the resident's behavior was fast and strenuous. The Indoor/Out-door (I/O) ratio for the giant PM larger than $5.0{\mu}m$ was 1.16. It was possible to identify PM types and estimate the resident's behavior through the comparison the theoretically calculated and the measured retention times for several types of PM in an indoor site. The theoretically reconstructed mass concentration of $PM_{2.0-0.3}$ suggested that the portion of $PM_{2.5}$ in indoor was quietly occupied by $PM_{0.3}$ or the PM inherently originated from indoor environment.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.2
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• pp.191-202
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• 2007

We developed an in-situ analyzer to understand the HONO levels in indoor environments. The in-situ measurement system utilizes a diffusion scrubber and luminol chemiluminescence to measure the HONO concentration with time resolution of 4-minute. Concentrations of NO, $NO_{2}$, and HONO were determined at an indoor air of an apartment for 9 days using the developed in-situ analyzer. Indoor HONO concentrations were highly elevated when a gas range was operated. Enhancements of the indoor NO, $NO_{2}$, and HONO concentrations during combustion indicate that the observed indoor HONO was formed by direct emission. In addition to the direct emission, the indoor HONO was partially generated from heterogeneous reactions of $NO_{2}$ on indoor surfaces, which was supported by strong relationships between peak NO, $NO_{2}$, and HONO concentrations, high HONO/$NO_{2}$ ratio and a weak correlation between NO and HONO concentrations. Additionally, three combustion experiments during the whole measurement period were performed to investigate the effects of unvented and vented gas burning on the HONO, NO, and $NO_{2}$ concentrations and their decay. The decay rate of the HONO concentration was significantly less than the NO and $NO_{2}$ decay rates for all the experiments, indicating that the lifetimes of trace nitrogen species in indoor environment varied in the order approximately HONO>$NO_{2}$>NO.

• Journal of Environmental Science International
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• v.20 no.1
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• pp.61-69
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• 2011

Perceived air quality (PAQ) is defined as evaluation of indoor air satisfaction and comfortable sensory by occupants. However, there are differences between criteria of indoor pollutants and lowest sensory thresholds. In this study, we compared indoor PAQ by questionnaire with measured benzene, toluene and nitrogen dioxide ($NO_2$) concentrations in home indoors. The $NO_2$ concentration was the highest in Seoul, while benzene and toluene were the highest in Asan. Average PAQ score in winter was higher than that in summer. Significant correlations between PAQs of home indoor air pollution and measured pollutant concentrations were not shown and correlation coefficients (r) ranged between -0.453

• Journal of the Korean housing association
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• v.20 no.3
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• pp.1-10
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• 2009

The final aim of this study was to propose guidelines for the indoor environment of apartment remodeling projects. The first task of this study was to understand the major elements and the actual condition of the remodeling for apartment unit by carrying out in-depth interviews on residents and specialists. The open-access interviews were conducted with interior designers who have a wide experience of apartment remodeling and residents who live in recently remodeled apartment units. The second task was to evaluate the actual condition of the indoor environment and to analyze the main factors that affect the indoor environment in remodeled apartment units. Field measurements were carried out in twenty apartment units occupied after remodeling, recording indoor environment elements (indoor temperature, globe temperature, relative humidity, $CO_2$, CO, PM10, TVOC, HCHO, illumination, and equivalent noise level). Moreover, resident interviews and researcher observations were carried out to determine the contents of the remodeled unit and to investigate the architectural and living factors(like ventilation characteristics, etc.) related to the indoor environment. The results are as follows. The remodeling elements generally included the changing of lighting fixtures and finishing materials in all the spaces, the integration of the balcony into the children's room, the installation of furniture in the kitchen and the entrance, the changing storage furnitures and equipments in the bathroom. The average levels of each unit of relative humidity, $CO_2$, TVOC, HCHO, equivalent noise level, and illumination were proved to be on the whole in inadequate condition. The factors that affect these indoor elements were classified as remodeling factors (remodeling amounts, extent balcony integration, and lighting fixture exchange), ventilation characteristics, and living factors. According to these results, this research proposed the guidelines for the indoor environment in apartment remodeling projects.

• Journal of Radiation Protection and Research
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• v.40 no.3
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• pp.155-161
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• 2015

Radon is a naturally occurring radioactive gas and a major indoor contribution of exposure to ionizing radiation in dwellings. $^{222}Rn$ is a health hazard gas what is responsible for thousand lung cancer deaths every year. In this study, indoor radon concentrations present in thirty representative houses in Mahallat city, Iran, were determined in order to estimate lung cancer risk associated with residential radon exposure. Long-term passive method, using CR-39, was used to measure the radon concentration. The results showed an association between the age of the dwellings and the indoor radon concentration that was found, in that the concentration of radon tended to increase as the age of the dwelling also increased. The indoor radon concentrations were calculated to be within the range of $23{\pm}2$ to $350{\pm}26Bq{\cdot}m^{-3}$, with an average of $158Bq{\cdot}m^{-3}$. The annual effective dose from inhaled radon and its decay products was calculated between $0.8{\pm}0.1$ and $12.3{\pm}0.9mSv{\cdot}y^{-1}$, with an average of $5.5mSv{\cdot}y^{-1}$. By taking into consideration the EPA recommendation and ICRP statement, the average annual risk of lung cancer from inhaled radon was calculated as 0.09%, 0.06%, 0.01%, and 0.03% for current smokers (CS), those who had ever smoked (ES), never smokers (NS) and the general population, respectively.

• Spatial Information Research
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• v.21 no.2
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• pp.11-21
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• 2013

W ith the recent increasing build and application for 3D spatial information, the importance of management and application for spatial information based on indoor space has been increased. Especially, Due to the increasing of the scale and complexity of the building according to the development of construction technologies several studies have been conducted to provide the services based on indoor space such as indoor navigation for disaster. Therefore, to efficient manage and service for information of complicated indoor space, it is necessary to extend and develop 3D spatial model and services that have been developed for outdoor space. In this paper, Indoor Spatial Data Model(ISDM) is developed to support building spatial information for complicated indoor space and location based services through topological information. ISDM contains a feature model which is a CityGML Application Domain Extension(ADE) model and a topology model that refers the IndoorGML.