• 한국산업보건학회지
• /
• 제25권2호
• /
• pp.174-183
• /
• 2015

Objectives: The objective of this study is the estimation of factors influencing airborne fiber concentrations by means of an observation survey of asbestos-containing materials in buildings. Methods: Forty-five samples were collected from four commercial buildings by NIOSH Method 7400 and classified according to current condition, potential activity, construction year, and operations and maintenance(O&M). Results: Airborne fiber concentrations by current condition(classified as good, fair and poor) were significantly different(p<0.05). Concentrations by potential activity were significantly different among groups(p<0.05), and those from the low activity group were higher than those from the middle activity group. Based on construction year, airborne fiber concentrations from the decade of the 1990's were higher than those from the 1960's. When O&M status was considered, airborne fiber concentrations from 1960's buildings were lower than those buildings not operated and maintained(p<0.01), because dust generation was influenced by O&M status. It was found that airborne fiber concentrations were related to current condition and potential activity via regression analysis, but the coefficient of determination was low. Also, correlation analysis showed that the higher the potential activity, the more current condition is worsened, but the relationship was not significant(r=-0.455, p>0.05). Conclusions: Airborne fiber concentrations in asbestos-containing buildings had weak relationships with current condition and potential activity.

• 한국직업건강간호학회지
• /
• 제19권1호
• /
• pp.88-96
• /
• 2010

Purpose: The aim of the present study was to clarify effects of long term, low-level monocyclic aromatic hydrocarbons exposure (MAHs) such as styrene, toluene and xylene on physiological levels of epinephrine (EP) and norepinephrine (NEP) and these hormones influences diagnosis indices of metabolic syndrome (MetS). Methods: Blood pressure and serum biochemical parameters were measured using digital sphygmomanometer and autochemical analyzer. EP and NEP were analyzed by using ELISA kit and exposure level of MAHs was measured by NIOSH method. Results: The differences of general characteristics such as age, smoking and drinking habits in both groups were not significantly different except working hours per day. In exposed workers, exposure levels of MAHs showed very low concentrations. Serum HDL-cholesterol concentration was significantly higher in exposed group, but concentration of NEP was significantly higher in control group. On multiple logistic regression analysis for the diagnosis indices of MetS, EP was WC (OR=0.970), NEP was blood pressure (OR=1.002) and MAHs exposure were significantly associated with HDL-cholesterol (OR=0.257), fasting glucose (OR=3.028) and MetS (OR=0.372). Conclusion: These findings suggest that the chronic exposure of low level MAHs maycontribute to glucose metabolism and induction of MetS. And also, changes of EP and NEP levels by exposure of MAHs affect blood pressure.

• 한국환경과학회지
• /
• 제16권3호
• /
• pp.323-331
• /
• 2007

Polycyclic aromatic hydrocarbons (PAHs) are well known for strong carcinogen. However, the human exposure analysis of PAHs is quite difficult and unreliable because of hard for estimation of actual expose dose. Then urinary 1-hydroxypyrene (1-OHP) has been a biological marker of exposure to PAHs. The purpose of this study was to investigate total amount from exposure to PAHs soused by indoor occupational exposure, and residence at Seoul metropolitan area and Kyeonggi province in Korea. Thirty-five housewives were included in this study from April 2003 through February 2004. Dietary habit and general characteristics such as age, type of building, existence of passive smoking, period of residence, fuel type for heating and ventilation type were obtained by self administered questionnaire. Urine samples were collected at morning and freeze quickly. Urinary creatinine was measured for converting into 24 hr urine. Concentration of the indoor PAHs was examined by NIOSH method number 5506. Urinary 1-OHP and PAHs were analysed by HPLC. Correlation coefficient between urinary 1-OHP levels and pyrene concentration of indoor air was 0.66 and statistically significant(P<0.01). The difference of urinary 1-OHP level due to dietary habits were not significant. Urinary 1-OHP level of Spring, Summer, Autumn, and Winter were $0.21{\pm}0.12,\;0.10{\pm}0.17,\;0.16{\pm}0.12,\;0.17{\pm}0.14{\mu}g/g$ cr, respectively. The arithmetic means of urinary 1-OHP for four season tee $0.16{\pm}0.14 {\mu}g/g$ cr. There was a trend that urinary 1-OHP level of residents who dwelling in apartment were higher compared with detached home, Comparison of 1-OHP level between heating by kerosene and LPG, Much higher gas heating type than kerosene type (P<0.05). This result implies that the urinary 1-OHP can be applied as the PAHs exposure indices.

• 한국환경보건학회지
• /
• 제26권4호
• /
• pp.21-28
• /
• 2000

Various man-made mineral fibers(MMMF) including refractory ceramic fiber(RCF) have been used widely in industries as insulation materials. The effect of fibrous dust on human health depends on fiber size, concentration (exposure level), and durability in biological system. Therefore, these parameters should be determined to evaluate accurately the potential risk of fibers on human health. The purpose of this study was to characterize the size of airborne fiber and the workers＇ exposure to airborne fibers in refractory ceramic fiber manufacturing and processing factories. Airborne fibers were collected on 25-mm mixed cellulose ester membrane filters at personal breathing zones, and analyzed by A and B counting rules of the National Institute for Occupational Safety and Health(NIOSH) Method # 7400. The average ratios of the fiber density by B rule to the fiber density by A rule was 0.84. This result indicates that the proportion of respirable fibers (<3 ${\mu}{\textrm}{m}$ diameter) in air samples was high. The average diameter and length of airborne fibers were 1.05${\mu}{\textrm}{m}$ and 35${\mu}{\textrm}{m}$, respectively. The average fiber concentrations (GM) of all personal samples was 0.26f/cc, and the average concentration was highest at blanket cutting and packing processes. The fifty seven percent of personal air samples was exceeded the proposed American Conference of Governmental Industrial Hygienists(ACGIH) Threshold Limit Value(TLV), i.e. 0.2 f/cc. It was concluded that the RCF industrial workers had the higher potential health risk due to small fiber diameter, long fiber length, and high exposure level to the airborne fibers.

• 한국산업보건학회지
• /
• 제22권2호
• /
• pp.134-139
• /
• 2012

Objectives: This study was conducted to study the analytical variability of A & B counting rules in counting using a phase contrast microscope airborne fibers collected on filters in man-made mineral or vitreous fibers (MMMFs) industries. Methods: Fibers in filters were counted using A & B rules of NIOSH Method 7400. Intra-counter and inter-counter variations by fiber type and density were obtained. The types of MMMFs analyzed were glass wool fiber, rock wool fiber, slag wool fiber, and refractory ceramic fibers. The densities of fibers classified were <20 $fibers/mm^2,$ 20 - <50 $fibers/mm^2$, 50 - <100 $fibers/mm^2,$ and ${\geq}100$ $fibers/mm^2,$ respectively. Results: Intra-counter relative standard deviations by rule A were 0.084, 0.102, 0.071 for glass wool fibers, rock wool fibers and refractory ceramic fibers, and those by rule B were 0.139, 0.120 and 0.142, respectively. Inter-counter relative standard deviations by rule A were 0.281, 0.296, 0.180 for glass wool fibers, rock wool fibers and refractory ceramic fibers, and those by rule B were 0.396, 0.337 and 0.238, respectively. Conclusions: Intra-counter variation was not different significantly among fiber types (p>0.05), but B rule variation for ceramic fibers approximately 2 times greater than corresponding A rule estimates, and intra-counter and inter-counter variations were higher in the low fiber density.

• 한국산업보건학회지
• /
• 제23권1호
• /
• pp.20-26
• /
• 2013

Objectives: This study was conducted to evaluate the health risk of workers exposed to butyl glycidyl ether to prevent them from developing occupational diseases. Methods: The workplaces that coat floor with epoxy were selected and the samples were collected and analyzed with NIOSH 1616 Method. We calculate workplace reference concentration using with NOAEL estimated by the study of Anderson et al. in 1978. Risk was calculated by the ratio of exposure to workplace reference concentration. Monte-Carlo simulation was performed to derivate the median, cumulative 90%, and cumulative 95% value by using Crystal Ball. Results: Butyl glycidyl ether is a skin, eye irritator and can result in central nervous system depression, allergic reaction. NOAEL was 38 ppm and workplace reference concentration was calculated as 0.73 ppm corrected with uncertainty factors. Geometric mean was 1.152 ppm and geometric standard deviation was 1.522 by the workplace environment measurement. The median, cumulative 90%, and cumulative 95% value of risk were calculated as 1.617, 1.934, and 2.092, respectively. Conclusions: Not only cumulative 90% and cumulative 95% value but also the median of risk is higher than 1.0 by the risk characterization, so it can do a lot of harm to workers. Therefore, the process of derivating workplace reference concentration and the appropriacy of the uncertainty factors should be re-examined.

• 한국산업보건학회지
• /
• 제29권3호
• /
• pp.271-277
• /
• 2019

Objectives: A 46-year-old woman who had worked on cleaning stainless steel containers with Initially unknown powders died from acute silicosis. To determine whether the acute silicosis was related to his work environment, we conducted exposure assessment the level of exposure to respirable crystalline silica(RCS) during cleaning stainless steel containers with unknown powders. Methods: The exposure assessment of RCS were undertaken according to the National Institute for Occupational Safety and Health(NIOSH) method 7500. The components of the unknown powder were analyzed using X-ray Diffraction. Results: The unknown powder was found to be natural diatomaceous earth, which contained 12% and 9% quartz and cristobalite, respectively, crystalline silica. In the case of cleaning stainless steel containers with diatomaceous earth powder, the primary measurement resulted in 1.3 times higher occupational exposure limit of MOEL(in sum of quartz and cristobalite concentration) and 3.9 times higher in secondary measurement. The workbench was equipped with a local exhaust system, but because there was no hood at the end of the duct, the wind speed at the opening of the duct was 12 m/sec, whereas the controlled wind speed at the working position was only 0.3 m/sec below the legal standard. Conclusions: There is an urgent need to install the hood, conduct safety and health education for employers and workers, and periodically monitoring and manage the working environment.

• 한국산업보건학회지
• /
• 제31권4호
• /
• pp.461-472
• /
• 2021

Objectives: This study was conducted to determine the differences in EC concentrations according to the type of sampler by measuring and analyzing EC. Methods: Elemental carbon was measured in diesel engine vehicles and at the roadside. Using NIOSH method 5040, a cassette was coupled to 37 mm and 27 mm quartz filters and measurements were performed 21 times. There were 14 types of measurement methods, and polystyrene, polypropylene, and metal samplers were evenly placed inside the movable chamber. Results: The results measured using the 37 mm conductive cassette (closed/open) and the IOM sampler made of conductive materials showed a higher ratio than the other results. When the 37 mm conductive cassette was measured with the lid open, it showed a statistically significantly higher ratio than with other measurement methods (p<0.05). Conclusions: Checking the EC concentration a total of 21 times at each ratio based on the concentration of the 3-stage polystyrene cassette, it was statistically significantly higher when the 37 mm conductive cassette was open. This same cassette also showed a slightly higher EC concentration when closed. It was ascertained that some DEE was collected on the cassette wall surface due to the electrical conductivity of the polystyrene cassette, resulting in sample loss. Since EC is composed of fine particles, it is thought that electrical conductivity may affect its concentration.

• 근관절건강학회지
• /
• 제16권1호
• /
• pp.13-25
• /
• 2009

Purpose: The purpose of this study was to investigate the relationships between job stress and work-related musculo-skeletal symptoms among nurses working in general hospitals. Method: A descriptive correlational research design was utilized. The participants were 438 nurses currently working in 4 general hospitals. Data were collected from Jan 2007 to Feb 2007, with Korean Occupational Stress Scale(KOSS)-basic form, KOSHA code H-30 and a questionnaire for general characteristics. Descriptive statistics, t-test, ANOVA, multiple logistic regression analyses were utilized. Result: Most participants(90.4%) complained of work-related musculo-skeletal symptoms. However, symptomatic nurses satisfying NIOSH screening criteria(symptomatic nurses) were 66.9%(293 persons). The most complained body part was back(39.5%). shoulder(37.7%), leg and foot(36.5%), wrist and hand(21.7%), neck(18.7%), and arm(9.8%). The mean of total score of occupational stress was 51.11. In multiple logistic regression analyses, age, working posture and total score of occupational stress showed significant associations with back symptoms. Exercise and total score of occupational stress were significantly related with shoulder symptoms. Hours of daily house keeping and working posture were related with leg and foot symptoms. Marital status and working posture were related with wrist and hand symptoms. Working posture only showed significant relations with neck symptom. Marital status, hours of daily house keeping, shift work, working posture, and total score of occupational stress were related with the symptoms in the arm. In conclusion, job stress of nurses might be related with work-related musculo-skeletal symptoms.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1995년도 춘계학술대회논문집; 전남대학교, 19 May 1995
• /
• pp.153-158
• /
• 1995

보 및 평판의 진동에 대해서 에너지의 손실은 재료감쇠를 이용한 표면감쇠처리나 지지부에서의 감쇠처리에 의하여 증가될 수 있다. 감쇠재료를 이용한 표면감쇠처리의 예로서 보/평판 표면에 접착되는 감쇠 테이프나 코팅등은 아주 효과적임이 입증되었다. 마찬가지로 지지부 감쇠처리는 점탄성재료의 삽입에 의해서 설명될수 있다[1]. 보/평판의 감쇠에 대한 최근의 많은 연구들은 진동하고 있는 보/평판의 표면에 적용하는 감쇠 테이프 혹은 적층형태의 감쇠 처리방법에 대해서 주로 수행되었다. 일반적으로 표면감쇠처리방법은 진동감소에 아주 효과적이지만 실제 적용상에서 항상 가능한 것은 아니며, 이와 같은 경웨는 지지부 감쇠 처리방법에 의존하게 된다[2]. 감쇠특성을 갖는 점탄성재료를 실제로 적용할 때 보/평판의 유한한 길이가 점탄성재료로 지지되며 점탄성재료의 물성치와 치수에 따라서 계의 모우드 매개변수(고유진동수, 계의 손실계수 그리고 모우드형상)가 크게 달라진다. 그리고 이와 같은 계에 대해서는 지지부의 거동보다는 전체 시스템의 고유진동수와 손실계수 그리고 보 영역에서의 모우드 형상에 더 관심이 있으므로 지지부 영역을 집중매개변수(lumped parameter)로 나타내어 계를 해석할 수 있다. 일반적으로 보와 평판의 경계에서는 병진 및 회전방향의 강성 뿐만 아니라 두 강성사이에 연성효과도 동시에 발생하게 되므로 이 항을 고려하여 계를 모델링해야 한다. 본 연구에서는 우선 점탄성 재료에 의한 지지부영역의 등가 강성계수들을 구하고 경계에 강성행렬을 갖는 보의 등가시스템을 얻는다. 그리고 등가시스템의 주파수방정식으로부터 모우드 매개변수에 대한 지지부의 영향을 살펴본다. 또한 시스템이 비교적 복잡한 사각 평판의 진동에 대해서도 동강성행렬법(dynamic stiffness matrix method)을 이용하여 해석하고자 한다. 수준임이 입증되었다. 본 연구의 결과를 토대로우리나라 젊고 건강한 남성에게 적합한 무게상수는 작업자군에 대하여 25.05kg, 학생군에 대하여 20.24kg 으로 나타나 이는 미국 NIOSH 안전기준과 대체로 일치함을 발견하였다.ive structures utilized in Client/server architecture for distribution and cooperative processing of application between server and client this study presents two different data management methods under the Client/server environment; one is "Remote Data Management Method" which uses file server or database server and. the other is "Distributed Data Management Method" using distributed database management system. The result of this study leads to the conclusion that in the client/server environment although distributed application is assumed, the data could become centralized (in the case of file server or database server) or decentralized (in the case of distributed database system) and the data management method through a distributed database system where complete responsi