• 환경위생공학
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• 제17권3호
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• pp.67-74
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• 2002

Nowadays, a new word called SBS(sick building syndrome) has been come into existence. Since most people spend a large majority of their time indoors, indoor air may affect human health more than outdoor air. This outline survey was carried out to investigate the extent of indoor air pollution in singing room and PC room. The concentrations of major indoor air pollutants(carbon dioxide, total suspended particulate, airborne microbes) and Thermocircumstance(temperature, relative humidity, intensity of illumination) were observed from October 1 to 31, 2001. As results of the survey, the mom values of thermocircumstance in singing room and PC room were $22.1^{\circ}C$ of temperature, 37.1% of humidity, 75 Lux of intensity of illumination and $22.0^{\circ}C$ of temperature, 52.6% of humidity, 135 Lux of intensity of illumination, respectively. The mean concentrations of carbon dioxide were 1589 ppm in singing room and 615 ppm in PC room, respectively The concentrations of carbon dioxide in singing room were higher than the indoor environmental standard of the first clause of Article 45 of public utilization service which is showed at public hygiene of the Ministry of Health and Social Affairs. The mean concentrations of total suspended particulate were $0.33{\;}mg/\textrm{m}^3$ in singing room and $0.57{\;}mg/\textrm{m}^3$ in PC room respectively. The mean concentrations of airborne microbe were $16{\;}CFU/\textrm{m}^3$ in singing room and $12{\;}CFU/\textrm{m}^3$ in PC room, respectively.

• 한국컴퓨터정보학회논문지
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• 제23권11호
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• pp.143-149
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• 2018

The purpose of this study is to propose a management method to maintain the pleasant indoor air quality of the dental clinic by measuring and analyzing the indoor air quality of the dental clinic. The measurement was conducted in two rooms, a lobby where many residents stay in the reception room for waiting for medical treatment, and a VIP room where treatment activities are mainly performed. Measurement items are Temperature, Humidity, $CO_2$, CO, $NO_2$, $CH_2O$, VOC, $PM_{10}$ and measurement were taken on April 27, 2018. As a result of analyzing the temperature and humidity of the dental clinic, it was analyzed that the average indoor temperature was maintained at $25^{\circ}C$ and the humidity was kept at around 50%, maintaining proper indoor temperature and humidity environment. $CO_2$ was 855ppm in the VIP Room, which satisfied the maintenance standard. In the case of the lobby, it was analyzed to be 1,160ppm, which exceeded the maintenance standard and it is judged that the carbon dioxide generated by the respiration of the people staying in the lobby is the main reason. The mean concentration of formaldehyde in the VIP room was analyzed as $436{\mu}g/m^3$, exceeding the maintenance standard, and $2,100{\mu}g/m^3$ for the VOC exceeded the recommended standard. It was analyzed that the concentration was relatively higher due to the use of disinfectant and other drugs. The mean concentration of PM-10 in the lobby was analyzed as $65{\mu}g/m^3$ and it was analyzed that it satisfied the maintenance standard. To maintain a pleasant indoor air quality in a dental clinic it is necessary to minimize the effects of formaldehyde, VOC, $CO_2$ in the VIP rooms and lobby. For this purpose, the entire ventilation system and air purification system of the dental clinic should be installed. In case of the VIP room, local exhaust ventilation should be installed and workers should wear personal protective equipment.

• 한국산업보건학회지
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• 제24권4호
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• pp.453-461
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• 2014

Objective: Based on the fact that fine particles are more likely to produce negative influences on the health of occupants as well as the quality of indoor air compared to coarse particles, it is critical to determine concentrations of aerosol particles with different sizes. Thus, this study focused on the size distribution and concentrations of aerosol particles in university buildings. Method: Aerosol particles in indoor air were collected from four areas: corridors in buildings(In-CO), lecture rooms(In-RO), laboratories(In-LR), and a cafeteria(In-RE). Samples were also collected from outside for comparison between the concentrations of indoor and outdoor particles. For the collection of the samples, an eight stage non-viable cascade impactor was used. Result: The average concentration of $PM_{10}$ in the samples collected from indoor areas was $34.65-91.08{\mu}g/m^3$,and the average for $PM_{2.5}$ was $22.65-60.40{\mu}g/m^3$. The concentrations of the aerosol particles in the corridors, lecture rooms, and laboratories were relatively higher than the concentrations collected from other areas. Furthermore, in terms of mass median aerodynamic diameter(MMAD), the corridors and lecture rooms had higher numbers due to their characteristics, showing $2.36{\mu}m$ and $2.11{\mu}m$, respectively. Laboratories running an electrolysis experiment showed $1.58{\mu}m$, and the cafeteria with regular maintenance and ventilation had $1.96{\mu}m$. Conclusion: The results showed that the $PM_{10}$ concentrations of all samples did not exceed indoor air quality standards. However, the $PM_{2.5}$ concentration was over the standard and, in particular, the concentration of fine particles collected from the laboratories was relatively higher, which could be an issue for the occupants. Therefore, it is important to improve the quality of the indoor air in university buildings.

• 한국융합학회논문지
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• 제8권1호
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• pp.71-76
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• 2017

본 연구는 다중이용시설등의 실내공기질 관리법에 의해 시행되고 있는 의료기관의 실내공기질을 조사하여 관리실태를 파악하고 장소에 따라 나타나는 차이를 융합적으로 분석하여 세부적 관리방안을 제시하기 위한 목적으로 실시하였다. 부산광역시에 소재하는 의료기관 153개를 대상으로 직접 방문조사하여 미세먼지($PM_{10}$), 이산화탄소($CO_2$), 포름알데하이드(HCHO), 총부유세균(TAB), 일산화탄소(CO)를 조사하였다. 연구결과를 살펴보면, 전체적 산출평균은 유지기준을 초과하지 않았으나, 항목별 최대값은 $PM_{10}$이 91%, $CO_2$가 97%, HCHO가 96%, TAB가 99%에 해당하여 기준에 매우 근접하는 것을 확인하였다. 또한, 유동인구와 관련하여 측정 장소를 다르게 하여 측정한 결과는 각 특징에 따라 서로 다른 값을 보였다. $PM_{10}$은 로비에서 $61.80{\pm}9.66{\mu}g/m^2$, $CO_2$는 복도에서 $632.08{\pm}112.86ppm$으로 가장 높게 나타났다. 반면, HCHO는 입원실이 $21.88{\pm}17.03{\mu}g/m^2$으로 가장 높은 것으로 나타났다. TAB와 CO는 복도에서 각각 $634.08{\pm}46.41 CFU/m^2$와 $0.81{\pm}0.66ppm$으로 가장 높았다. 5곳의 측정결과 유의한 차이는 없었다. 결과적으로 의료기관 실내공기는 불특정 다수인들이 수시로 출입가능하며 환자들이 주로 생활하는 시설적 특징을 충분히 고려하여 보다 세밀하고 체계적인 관리가 이루어져야 한다.

• 한국산업보건학회지
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• 제8권2호
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• pp.209-223
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• 1998

The aim of this study was to evaluate welders' exposure to hexavalent chromium (Cr(VI)) and nickel (Ni) during welding operations in a Korean shipyard. The airborne Cr(VI) and Ni concentrations were measured during metal inert gas (MIG) welding on mild and stainless steel, and manual metal arc (MMA) welding on mild steel. The geometric mean (GM) of Cr(VI) concentrations inside the welding helmet during MIG welding on mild steel were $0.0018mg/m^3$ inside a ship section, and $0.0015-0.0026mg/m^3$ at the welding shops. All of the personal breathing zone air samples were below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value ($TLV^{(R)}$) of $0.01mg/m^3$. Conversely, eighty-eight percent(21 of 24) of the personal breathing zone air samples exceeded the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit of $0.001mg/m^3$. Ni was not detected on 20 of 23 air samples collected during MIG welding on mild steel. The three Ni samples above the limit of detection ranged from 0.015 to $0.044mg/m^3$. The GM of Cr(VI) concentrations during MMA welding on mild steel were $0.0013mg/m^3$, but Ni was not detected in the air samples during this operation. It is assumed that the airborne Cr(VI) and Ni during mild steel welding were derived from the base metals which contained about 0.03% Cr and 0.03% Ni. The GM of airborne total Cr, Cr(VI) and Ni concentrations during MIG welding on stainless steel were 4.02, 0.13 and $0.86mg/m^3$, respectively, and the levels of Cr(VI) and Ni were above the ACGIH-$TLV^{(R)}$. Cr(VI) comprised about 35.5% of the total chromium(Cr) from MIG welding on mild steel, and about 8.4% of total Cr from MIG welding on stainless steel. The ratios of Cr(VI) to total Cr were significantly different among welding shops. It was concluded that welders were exposed to high levels of Cr(VI) and Ni during welding on stainless steel, and were exposed to low levels of Cr(VI) even during welding on mild steel.

• 한국산업보건학회지
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• 제33권2호
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• pp.103-114
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• 2023

Objectives: This study was conducted to evaluate hand-arm vibration (HAV) exposure levels due to the use of power hand tools and to evaluate the determinants in the automobile assembly process. Methods: The exposure level to HAV was evaluated for 30 work lines in five assembly processes (body, engine, chassis, door, and design) that use air-powered tools and battery-powered tools and operate in circulation for two hours. The 2-hr equivalent energy vibration acceleration, A (2), of the task was measured. The 8-hr equivalent energy vibration acceleration, A (8), was estimated in consideration of the number of tasks that can be performed per day by each process. In addition, a survey on the working environment was conducted with workers exposed to vibration. Results: The geometric mean of the HAV exposure level, A (2), for a total of 30 tasks was 2.51 m/s², and one case was 10.30 m/s², exceeding TLV (2hr). The HAV exposure level of A (8) was evaluated from 1.03 m/s² to 5.36 m/s². A (2) showed a statistically significant difference (P<0.01) for each process, and the chassis process (GM=3.90 m/s²) was the highest. The larger the tool size and the longer the tool length, the higher was the vibration acceleration when using a battery-powered tool than an air-powered tool (P<0.01). Battery-powered tool users showed higher dissatisfaction on all items than did air-powered tool users. Conclusions: As a result of this study, it is necessary to implement a program to reduce the HAV exposure levels.

• 한국산업보건학회지
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• 제10권1호
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• pp.223-234
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• 2000

Objective - To evaluate the usefulness of chromium in erythrocytes as a biological marker of exposure to hexavalent chromium in chromate producers and chrome platers Methods - Blood and urine samples were ramdomly obtained from chromate producers (n=34) and chrome platers (n=35), and non-exposed workers (n=75), chromium level in erythrocytes and plasma, and urine were measured. Different chromium exposure workers were assessed through measurements of airborne hexavalent chromium concentrations using a personal air sampler. Linear associations between variables were evaluated with correlation analysis. Results - The chromate producers had mean chromium levels in erythrocytes five fold as higher than the chrome platers, and fifteen fold higher than non-exposed group. Among the chromium exposed workers, airborne hexavalent chromium was positively and strongly correlated with in erythrocytes (r=0.689, p<0.01), and erythrocytes chromium was inversely correlated with hematocrit (r=-0.441, p<0.01), hemoglobin (r=-0.465, p<0.01) and the number of red blood cells (r=-0.28, p<0.05). Conclusions - In conclusion, this study suggests that chromium in erythrocytes is a good indicator of the chromium body burden caused by exposure to hexavalent chromium.

• 한국산업보건학회지
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• 제20권4호
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• pp.256-262
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• 2010

This study evaluated the airborne concentrations of fungi in university laboratories, hospital diagnostic laboratories in Seoul. The incubated fungi was identified by lactophenol cotton blue (LPCB) staining method. Variables such as types of ventilation, temperature and relative humidity were investigated to explain laboratory airborne fungal concentrations. A total of 97 air samples were collected from 10 facilities in two institutions. Aspergilus spp., including Aspergilus niger, Aspergillius flavos and Penicillium spp. were found as predominant species. Airborne fungal concentrations ranged from not detected (ND) to 1,890 CFU/$m^3$. Airborne fungal concentrations were high in general-ventilated facilities and in laboratories where relative humidity ( > 60 %) were high ( p < 0.001). Therefore, we suggest that relative humidity should be maintained to properly reduce the concentration of fungal in university and hospital laboratories.

• 한국산업보건학회지
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• 제20권4호
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• pp.248-255
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• 2010

Airborne nanoparticle concentrations in three metrics (particle surface area concentration, particle number concentration, and particle mass concentrations) were measured by task in a laboratory making carbon nanotubes (CNTs) films using three direct reading instruments. Because of the conducted other researcher's experiment before the tasks, airborne nanoparticle surface area and number concentrations are the highest at the first time conducted weighing and mixing by sonication task, respectively. Because of the mist generated during mixing by sonication, the highest airborne nanoparticle surface area and PM1 concentrations were measured in the task among the total. Nanoparticle surface area concentrations at the researchers' breathing zones had high correlation (r=0.93, p<0.01) with those measured at an area in the laboratory. This result indicates that nanoparticles generated during the experiment contaminated the whole room air. When the experiment performed all the fume hoods weren't operated and making CNTs films task were conducted in the out of the fume hoods. In conclusion, researchers performing making CNTs film experiments were exposed to airborne nanoparticles generated during the experiment without adequate controls. We recommend that adequate controls should be implemented so that workers' exposures to airborne nanoparticle are limited to minimum levels.

• 한국산업보건학회지
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• 제20권4호
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• pp.236-240
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• 2010

This study demonstrates the use of a chemical containing potassium superoxide (KO2) to convert carbon dioxide (CO$_2$) in air to oxygen (O$_2$). A oxygen generating closed-circuit SCBA (self contained breathing apparatus) removes carbon dioxide by a chemical reaction with potassium dioxide that consumes the carbon dioxide and produces oxygen. Considering the disasters, there is a need to develop strategies to enable the introduction of self-contained self rescuers (SCSR). The potassium superoxide reacts with the wears breath to produce oxygen and absorb carbon dioxide. If the respiration rate of a person is 5 MET (metabolic equivalent), to say 30 L/min, at disaster such as fire, mass of potassium superoxide was evaluated as 33.3 g with yield and safety factor. Four researchers tested on a laboratory treadmill breathing through SCSRs in a closed circuit, it appears useable for 9 minutes.