• Journal of odor and indoor environment
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• v.17 no.4
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• pp.355-361
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• 2018

Mold grows more easily when humidity is higher in indoor spaces, and as such is found more often on wetted areas in housing such as walls, toilets, kitchens, and poorly managed spaces. However, there have been few studies that have specifically assessed the level of mold in the indoor spaces of water-damaged housing in the Republic of Korea. We investigated the levels of airborne mold according to the characteristics of water damage types and explored the correlation between the distribution of mold genera and the characteristics of households. Samplings were performed from January 2016 to June 2018 in 97 housing units with water leakage or condensation, or a history of flooding, and in 61 general housing units in the metropolitan and Busan area, respectively. Airborne mold was collected on MEA (Malt extract agar) at flow rate of 100 L/min for 1 min. After collection, the samples were incubated at $25^{\circ}C$ for 120 hours. The cultured samples were counted and corrected using a positive hole conversion table. The samples were then analyzed by single colony culture, DNA extraction, gene amplification, and sequencing. By type of housing, concentrations of airborne mold were highest in flooded housing, followed by water-leaked or highly condensed housings, and then general housing. In more than 50% of water-damaged housing, the level of airborne mold exceeded the guideline of Korea's Ministry of Environment ($500CFU/m^3$). Of particular concern was the fact that the I/O ratio of water-damaged housing was greater than 1, which could indicate that mold damage may occur indoors. The distribution patterns of the fungal species were as follows: Penicillium spp., Cladosporium spp. (14%), Aspergillus spp. (13%) and Alternaria spp. (3%), but significant differences of their levels in indoor spaces were not found. Our findings indicate that high levels of mold damage were found in housing with water damage, and Aspergillus flavus and Penicillium brevicompactum were more dominant in housing with high water activity. Comprehensive management of flooded or water-damaged housing is necessary to reduce fungal exposure.

• Journal of Environmental Health Sciences
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• v.43 no.2
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• pp.157-166
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• 2017

Objectives: Exposure to hazardous air pollutants could be affected by sociodemographic factors such as age, gender and more. Information on time spent in microenvironments has a critical role in exposure assessment. The purpose of this study was to analyze the exposure pathways which influence personal exposure through time-activity patterns and sociodemographic factors. Methods: A total of 379 subjects were collected from the second term of the Korean National Environmental Health Survey. A questionnaire survey in relation to sociodemographic factors and a time-activity diary were carried out for personal exposure to toluene. Focusing on personal exposure to toluene, factors affecting personal exposure were analyzed using multiple regression analysis. Results: Participants spent their time in an indoor house for $16.8{\pm}4.0hr$, workplace or school $2.3{\pm}3.5hr$, and other indoor $2.1{\pm}2.2hr$. Sociodemographic factors were significantly different among each personal exposure and microenvironment. Time of staying at an office turned out to be a main factor from point of exposure in exposure pathway using multiple regression analysis. As a result, this means that exposure may be different according to the time of staying in each microenvironment. Conclusions: Personal exposure to air pollutants might be decided by time-activity pattern indicating when, where, and which activities people pursue, as well as individual sociodemographic factors.

• Journal of Environmental Health Sciences
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• v.42 no.6
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• pp.438-449
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• 2016

Objectives: Exposure to airborne bacteria is associated with adverse health effects such as respiratory and infectious diseases. This study evaluated airborne bacterial concentrations in the living rooms, kitchens, and toilets of 30 homes. Methods: Bacteria were sampled with an MAS100 impactor in three spaces in the subject homes between April 2014 and February 2015. Bacteria were grown on TSA plates for 48 hours at $35^{\circ}C$. The bacterial strains were isolated and amplified by polymerase chain reaction. Results: The most culturable bacteria were found in toilets ($624.0CFU/m^3$, GM: $417.3CFU/m^3$), followed by in the kitchen ($503.8CFU/m^3$, GM: $324.9CFU/m^3$). The dominant genera identified were: Staphylococcus sp.(19%), Micrococcus sp.(16%), and Bacillus sp.(11%) in the indoor air and Bacillus sp. (30%) in the outdoor air. Gram-positive bacteria comprised more than half of all colonies. Conclusion: In this study, culturable bacteria concentrations were higher than those reported in other spaces. Therefore, it is important to control relative humidity and remove moisture to prevent bacteria from multiplying. Additionally, the dominant species in indoor air were Staphylococcus sp. and Micrococcus sp. These are found on the human skin, mucous membranes, and hair, so human activity can affect bacterial distribution. Therefore, cleaning and controlling moisture are important for reducing indoor bacterial concentrations.

• Journal of the Ergonomics Society of Korea
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• v.34 no.2
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• pp.125-134
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• 2015

Objective: In this review we discuss the health effects among office workers. Background: Even if office workers are not exposed hazardous or harmful environment frequently, some problems could be happened to the office workers. Although serious occupational diseases rarely occur to the office workers, it is important to consider occupational risk factors for the office worker because the portion of the office workers is relatively high in all industries. Method: We divided possible health effects for the office workers into three categories; musculoskeletal disorders, indoor environment, and cerebro-cardiovascular diseases. We reviewed related articles, textbooks, and statistical materials non-systematically and described risk factors, related illnesses, and prevention strategies on each category. Results: Office workers have various musculoskeletal disorders to be intervened. By medical treatment, improving working environment, and ergonomic intervention, office workers can be prevented from musculoskeletal injuries. Poor indoor environment can cause many building-related illnesses or sick building syndrome. Although the etiology of some problems by poor indoor environment is not clear, it helps to maintain adequate humidity, temperature, and clarity of indoor air. Cerebro-cardiovascular diseases are a rising issue because office workers in Korea tend to work for a lot of time. To prevent the diseases, it is needed to work for adequate time, lengthen activity level, and manage other medical risk factors for the diseases. Conclusion: There is no distinct occupational disease for office workers. However, there are some aspects to consider the health effects of office workers and it is important to prevent the possible health problems. Application: A strategy against occupational diseases among office workers can be established by reviewing this article.

• Journal of Advanced Navigation Technology
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• v.19 no.1
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• pp.74-79
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• 2015

In this paper, in order to improve the error is utilized to location tracking the smart sensor detects a walking information user, RSSI is to provide an indoor position tracking system that is capable of correcting an error in terms weak. The acceleration sensor is able to detect the activity in the user walking and detects the number of step and the moving distance using the same. The Direction sensor is utilized as a digital compass, to detect the moving direction of the user. As a result of detecting the walking information using the sensor, it can be showed that this proposed indoor positioning system has a high degree of accuracy for the number of steps and the movement direction. Therefore, this paper shows that the proposed technique can correct the error of the location information to be problem in the conventional indoor location system which uses the only Wi-Fi APs by estimating the user's movement direction and distance using the sensors in smartphone without an additional equipment and cost.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.247-255
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• 2002

Indoor and outdoor nitrogen dioxide (NO$_2$) concentrations were measured and compared with measurements of personal exposures of 95 persons in Seoul, Korea and 57 persons in Brisbane, Australia, respectively. Time activity diary was used to determine the impact on NO$_2$ exposure assessment and microenvironmental model to estimate the personal NO$_2$ exposure. Most people both Seoul and Brisbane spent their times more than 90% of indoor and more than 50% in home, respectively. Personal NO$_2$ exposures were significantly associated with indoor NO$_2$ levels with Pearson coefficient of 0.70 (p＜0.01) and outdoor NO$_2$ levels with Pearson coefficient of 0.66 (p＜0.01) in Seoul and of 0.51 (p＜0.01) and of 0.33 (p＜0.05) in Brisbane, respectively. Using microenvironmental model by time weighted average model, personal NO$_2$ exposures were estimated with NO$_2$ measurements in indoor home, indoor office and outdoor home. Estimated NO$_2$ measurements were significantly correlated with measured personal exposures (r = 0.69, p＜0.001) in Seoul and in Brisbane (r = 0.66, p＜0.001), respectively. Difference between measured and estimated NO$_2$ exposures by multiple regression analysis was explained that NO$_2$ levels in near workplace and other outdoors in Seoul (p = 0.023), and in transportation in Brisbane (p = 0.019) affected the personal NO$_2$ exposures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.763-764
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• 2010

• Journal of the Korea Society of Computer and Information
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• v.24 no.8
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• pp.95-103
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• 2019

According to the Statistics Korea in 2017, the 10 leading causes of death contain a cardiac disorder disease, self-injury. In terms of these diseases, urgent assistance is highly required when people do not move for certain period of time. We propose an unusual event detection algorithm to identify abnormal user behaviors using dust, vision and activity sensors in their houses. Vision sensors can detect personalized activity behaviors within the CCTV range in the house in their lives. The pattern algorithm using the dust sensors classifies user movements or dust-generated daily behaviors in indoor areas. The accelerometer sensor in the smartphone is suitable to identify activity behaviors of the mobile users. We evaluated the proposed pattern algorithms and the fusion method in the scenarios.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.18-31
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• 2018

It is important to conduct various analyzes to evacuate occupants in advance, because the disaster can cause serious injury. Therefore, it is necessary to analyze all the predictable scenarios that may occur. In this study, we propose a method to analyze the evacuation of indoor disaster using activity - based transport model MATSim. We have developed the university building as target area and simulated about 5,000 occupants. The analysis scenarios are set as basic evacuation conditions, exit closures and emergency stair closures. As a result of analysis of each scenario, the evacuation time was analyzed to be about 5:40(340s) in the base scenario, increased by 15% in the scenario 2 and increased by 23% in scenario 3. As a result of this study, we suggest that it is important to manage illegal obstacles of emergency stairs for rapid evacuation. Therefore, this study can contribute to the effective disaster prevention strategy of the building.

• Korean Journal of Community Nutrition
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• v.14 no.6
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• pp.777-788
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• 2009

The purpose of this study was to assess physical activities and activity coefficient of preschool children and was to give some concrete information to activate outdoor play and to probe the suggestions to activate outdoor play. 42 preschool children (17 boys and 25 girls) were included. Body weight and height were measured and one-day activity diaries were collected by interviewing with their parents and kindergarten teachers. To measure physical activity during outdoor play, this study was researched the current conditions and content of outdoor play activity in daycare centers, and teacher's perceptions of that outdoor play. The average age of the subjects was 5.0 years. Average height, weight, body fat and body muscle of subjects were 108.9 cm, 18.9 kg, 17.7% and 26.8%, respectively. The subjects spent about 10 hours 39 minutes sleeping; 4 hours 16 minutes personal hygiene and computer working. They spent 88.2% of 24 hours (one day) in "very light activities" and 11.3% in "light activities". Activity coefficient (1.34) of weekday was significantly higher than that of weekend (1.21). And in this study, it was found that most of daycare centers (87.7%) have outdoor play space, 95.2% of them were garden. The teachers recognized that have a outdoor play frequency everyday (48%), three or four times (46%) in a week but they have three or four times (38%), one or two times (30%) because of various indoor program. Also, they recognized that have a outdoor play expending time 21-30 minutes (48%), 31-40 minutes (26%) but they have 21-30 minutes (64%). They answered that have frequency and expending time less than their recognition of outdoor play. Most of daycare center teachers perceived outdoor play to be as important as indoor play, and the teachers believed outdoor play supports children's physical, cognitive, social, and language development. The results of this study may be used to utilize as a basic data for estimate physical activity for preschool children and developed that exercise program to increase physical activity of daycare center outdoor play.