• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4047-4051
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• 2014

Modern apartment houses are constructed to be relatively airtight with a high heat insulation system to increase the energy efficiency. Such a system has a range of deleterious effects due to the insufficient ventilation. In this study, the ondol system, which is used as a heat source typical of winter in Korea, was set as the default system to evaluate the indoor heat environment according to the ventilation method, the factors of energy reduction by the ventilation system was analyzed. The experimental apparatus was used to simulate the ambient conditions for a certain constant temperature and humidity chamber. The experimental results showed that the supply water temperature higher air volume decreases with increasing supply air temperature in the following order: floor supply/exhaust > total heat exchange supply/exhaust > forced supply/exhaust. Through this study, the applicability of various ventilations could be examined.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.215-224
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• 2004

We report the high concentration episodes for PM$_{10}$, SO$_2$, NO$_2$, and $O_3$ in many urban areas Korea during 2002. The high concentration episodes are identified based on the National Ambient Air Quality Standards and the observations obtained from the Regional Air Monitoring Network composed of approximately 160 air pollution monitoring stations located in a number of major or big cities in South Korea including Seoul, Pusan, Daegu, and Incheon cities. The results show that the twenty cases of high concentration episodes in 2002 consists of both ozone warning episodes (6 cases) and high PM$_{10}$ concentration cases (14 cases), and one half of the latter are found to occur in association with the Yellow Sand (Asian Dust) phenomena. The most outstanding characteristics of the reported episodes are the excessively high levels of maximum PM$_{10}$ concentrations during the Yellow Sand period (i.e., exceeding 3,000$\mu\textrm{g}$/㎥ in April, 2002) and their variable occurrence frequencies across seasons. The high ozone concentration episode days are mainly resulting from both the high photochemical reactions and poor ventilations. The high PM$_{10}$ concentration days during non Yellow Sand periods, however, mostly occurred under the influence of synoptic meteorological conditions such as stagnant or slowly passing high pressure centers, and consequently prevailing weak wind speeds over the Korean peninsula. The overall results of our study thus suggest the importance of both synoptic and local meteorological factors for high concentration levels in the major and/or big cities in Korea.n Korea.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.6
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• pp.561-571
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• 2014

The standards of ventilation system for bi-directional tunnel have not been established now. For this reason, with regard to the bi-directional tunnel below 1km, some problems have been appeared in ventilation capacity designing and in determining whether the mechanical ventilation system is needed or not for each case. In this study, we examine the characteristics of natural ventilations, analyze ongoing ventilation design cases for bi-directional tunnels and classify those cases into two groups. This study is carried out about the capability of using natural ventilating system by calculation of reasonable ventilation capacity in bi-directional tunnel and review of relationship between natural wind speed ($Vr^*$) and required speed(Vreq). This paper aims at providing a basis data for bi-directional tunnel ventilation design standards.

• 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 Korean Society of Occupational and Environmental Hygiene
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• v.26 no.4
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• pp.389-395
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• 2016

Objectives: Acute methanol poisonings known to be typical occupational diseases occurring in developing countries broke out in sub-contract manufacturers in the early 2016. The present paper attempted to identify underlying causes which hide under apparent findings, and suggest alternative policies to prevent recurrence of similar intoxication Methods: We evaluated occupational health and safety characteristics of workers in micro-enterprises similar to workplaces with methanol poisoning by in depth-interview of employers, workers, and labor inspectors, and literature review. Results: The common findings of workplaces with methanol poisoning were addressed; First, the victims were illegal agency workers. Second, the workplaces were sub-contract micro-manufacturers with less than 5 employees. Investigators found that local ventilations did not work, while most of workers did not wear any proper personal respiratory protective equipment in the workplace. In addition, periodic environmental monitoring and medical check-ups were not done. However, these apparent findings do not appear to be root causes of methanol poisoning. Our in depth-analysis clarified a root cause; micro-enterprises with less than 5 employees are exempted with essential regulations of OSH Act, and employers do not know about OSH Act. Conclusions: We suggest occupational health policies to prevent recurrence of similar intoxication; First, government should introduce programs so that all employers should know about employers' responsibilities in OSH Act from the start of business. Second, even manufacturers with less than 5 employees should not be exempted with essential regulations of OSH Act. Finally, employers should take responsibilities for health and safety of all the workers including agency workers working in workplaces.

• The Korean Journal of Emergency Medical Services
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• v.22 no.1
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• pp.49-59
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• 2018

Purpose: The purpose of this study was to develop an assistant device for the promotion of bag-valve-mask ventilation based on a non-equivalent control group pre-test and post-test design. Methods: The experimental tool was a mask assistance device developed by the researchers. Data were analyzed using SPSS 21.0 with the cardiopulmonary resuscitation (CPR) evaluation program from August 18 to 30, 2016. The research tools included general, hand-related, and ventilation-related characteristics. Results: Before and after using the mask assistance device, the tidal volume increased by 64 mL (p<.001) from 461.76 mL to 525.86 mL. The tidal volume for control was 477.86 mL, and there was a statistical difference (p<.05). The ventilation frequency in device users was 10 times per minute for a total of 20 ventilations with before 10.65 after 10 times, and that of the control group was before 10.36 times after 10 times; there was no difference in both groups(p>.05). The accuracy of the assistance device was $81.72{\pm}30.86%$, which was a very high value. However, the accuracy of ventilation in the control group with no assistance device was $18.97{\pm}32.44%$, which was a very low accuracy rate. Conclusion: This study's results suggested utilizing the newly-developed mask assistance device in CPR, and showed increases in tidal volume and accuracy of ventilation using the bag-valve-mask ventilation equipment. The general and hand-related characteristics did not have any effect, so the use of the device proved to increase the efficacy in all users.

• Fire Science and Engineering
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• v.20 no.4 s.64
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• pp.58-64
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• 2006

Smoke extraction in tunnel fire is investigated experimently with thermal model. The object is a immersed tunnel, of which the partial extraction system exists between the tubes. The model tunnel is measured 12 m long, 0.5 m wide and 0.35 m high. The fire is simulated to pool fire and the size corresponds to full scale fire of 5 MW based on Froude modeling. The performance of partial extraction system is determined under two ventilations, natural and longitudinal ones. The results show that compared with longitudinal ventilation, the smoke extraction efficiency of natural ventilation is increased about 30% because of smoke stratification in tunnel. Also the efficiency is identical to the iso-thermal model. The results will be help for activation of the ventilation system in emergency such as in the event of tunnel fires.

• Journal of People, Plants, and Environment
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• v.21 no.6
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• pp.445-460
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• 2018

Exposure to indoor air pollution is an emerging world-wide problem, with growing evidence that it is a major cause of morbidity worldwide. Whilst most indoor air pollutants are of outdoor origin, these combine with a range of indoor sourced pollutants that may lead to high pollutant levels indoors. The pollutants of greatest concern are volatile organic compounds (VOCs) and particulate matter (PM), both of which are associated with a range of serious health problems. Whilst current buildings usually use ventilation with outdoor air to remove these pollutants, botanical systems are gaining recognition as an effective alternative. Whilst many years research has shown that traditional potted plants and their substrates are capable of removing VOCs effectively, they are inefficient at removing PM, and are limited in their pollutant removal rates by the need for pollutants to diffuse to the active pollutant removal components of these systems. Active botanical biofiltration, using green wall systems combined with mechanical fans to increase pollutant exposure to the plants and substrate, show greatly increased rates of pollutant removal for both VOCs, PM and also carbon dioxide ($CO_2$). A developing body of research indicates that these systems can outperform existing technologies for indoor air pollutant removal, although further research is required before their use will become widespread. Whilst it is known that plant species selection and substrate characteristics can affect the performance of active botanical systems, optimal characteristics are yet to be identified. Once this research has been completed, it is proposed that active botanical biofiltration will provide a cheap and low energy use alternative to mechanical ventilations systems for the maintenance of indoor environmental quality.

• Fashion & Textile Research Journal
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• v.22 no.6
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• pp.844-852
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• 2020

This study is to understand the preferences of pilots, flight engineers and crew who work in the same aircraft but are exposed to different working environments and perform different mission operations in order to develop an ergonomic flight jacket. Based on a preliminary investigation, a survey of 107 pilots and 36 flight engineers and crew was conducted. The results are as follows; Pilots can control the temperature inside the cockpit, so they are less exposed to the cold when working, while flight engineers and crew are exposed to the cold more because they have many external tasks. The reason for the problem of the current flight jacket was a difference in ranking between two groups, but the highest ranking was poor dimensional suitability due to the habit of wearing layers of clothing. As a result of preferred design, there were significant differences between groups in the item of overall style. Pilots preferred a bomber jacket style(P:68.2%, E&C:44.4%), on the other hand, flight engineers and crew preferred a field jacket style(P:26.2%, E&C:55.6%)(p<.01). They preferred a stand collar(P:71.0%, E&C:86.1%), a fastener slider for a front fastening(P:62.6%, E&C:61.1%), fastener tape cuffs(P:54.2%, E&C:47.2%), a jacket with a softshell(P:86.9%, E&C:83.3%), fleece as softshell material(P:88.8%, E&C:69.4%), and fastener sliders as a attaching method(P:69.2%, E&C:61.1%). A hem fastening will be selected differently according to the overall style of outshell. Additionally, they preferred more than 5ea pockets(P:51.4%, E&C:44.4%), fastener sliders as pocket's fastenings(P:48.6%, E&C:61.1%), armpit ventilations(P:62.9%, E&C:58.5%). The results of above will be considered to design an ergonomic flight jacket.

• The Korean Journal of Emergency Medical Services
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• v.28 no.2
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• pp.99-108
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• 2024

Purpose: This study aimed to compare the effectiveness of one-hand compression method (one-hand) and two-thumb compression methods (two-thumb) using a 3-year-old pediatric mannequin. Methods: Participants in the experiment were randomly assigned to 21 people with one hand and 21 people with two thumbs, who had completed a basic life support training course. The mannequin used a few junior QCPR manikis (Laerdal, Norway), based on an age of 3. The study followed the guidelines for two-rescuer pediatric CPR, performing chest compressions and ventilations in a 15:2 ratio for 5 cycles, 10 minutes. The chest compression number, depth, speed rate, and recoil rate were measured after 1, 3, and 5 cycles, respectively. Data were analyzed using SPSS 23.0. Results: Comparing the efficiency of chest compressions performed during 1, 3, and 5 cycles, the depth of chest compressions was 40.84±3.10 mm for the two thumbs and 51.48±4.79 mm for the one-hand, which was significantly different (p<.001). According to pediatric CPR guidelines, the frequency corresponding to the compression depth range of 40.00-50.00 mm was statistically higher at 57.1% (12 people) of two thumb than at 23.8% (5 people) of one hand (p<.001). Conclusion: While the current guidelines recommend one- or two-thumb encircling hand compressions for larger children, the use of one- or two-handed wrapped thumb compressions should be considered for smaller children, depending on the rescuer's judgment, when distinguishing between a child and an infant is difficult.