• Journal of Environmental Health Sciences
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• v.32 no.2 s.89
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• pp.132-139
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• 2006

Number of aerosol, CO, $CO_2$ and TVOC after one-, two-, three-cigarettes smoking were monitored with time every 10 minute for 180 minutes in the seminar room (volume $51.1m^3$) when poorly-ventilated. IAQ monitor (IAQRAE, model PGM-5210) and PortCount (TSI, model 8020) were used for monitoring. Aerosol was decreased with exponential decay equation and it was estimated that number of aerosol would be long suspended (one cigarette 75/cc. two cigarettes 66/cc, three cigarettes 141/cc by 8hrs after smoking). While CO was also decreased with exponential or linear decay equation and correlated with number of aerosol strongly, TVOC and $CO_2$ were increased with linear equation in accordance with time lag. Most of TVOC and $CO_2$ were above standard levels of Korean Indoor Air Quality (Ministry of Environment) without regarding number of cigarettes. When naturally ventilated, all of CO, $CO_2$ and TVOC concentrations were dramatically decreased below standard levels of Korean Indoor Air Quality.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.1
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• pp.10-20
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• 2022

Objectives: The aim of this study is to evaluate exposure levels of the extremely low frequency magnetic fields(ELF-MF) radiated from various electric facilities in Liquid Crystal Display(LCD) manufacturing processes. Methods: This study measured the exposure levels of personal and local ELF-MF for the electronic facilities installed in two LCD manufacturing companies. Samplers were installed around workers' waist during working hours to identify personal exposure levels, and direct reading equipment were located at 3 cm, 10 cm, and 30 cm away from the surface of the electronic facilities to measure local exposure levels. Average and maximum(ceiling) values were calculated for personal and local exposure levels. Results: Average and maximum of personal exposure levels for each worker were 0.56(mean) ± 0.02(SE) µT and 6.31 ± 0.75 µT, respectively. Statistical analyses of the study found that maximum of the personal exposure levels for engineers was significantly higher than that for operators since engineers spend more time near the electronic facilities for repairing. The range of maximum personal exposure levels was 0.50 ~ 43.50 µT and its highest level was equivalent to 4.35 % of ACGIH(American Conference of Governmental Industrial Hygienists) exposure limit value(1 mT). Maximum of local exposure levels was 8.18 ± 0.52 µT and the electronic facilities with higher exposure levels were roof rail and electric panel, which were not related to direct manufacturing. The range of maximum local exposure levels was 0.60 ~ 287.20 µT and its highest level was equivalent to 28.7 % of the ACGIH exposure limit value. Lastly, the local exposure levels significantly decreased as the measurement distance from the electronic facilities increased. Conclusions: Maximum of personal and local exposure levels did not exceed the exposure limit value of ACGIH. However, it is recommended to keep the workers as far as possible from the sources of ELF-MF.

• Safety and Health at Work
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• v.2 no.3
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• pp.290-300
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• 2011

Objectives: There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methods: Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. Results: In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. Conclusion: When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system.

• Korean Journal of Occupational Health Nursing
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• v.26 no.1
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• pp.1-9
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• 2017

Purpose: This study was conducted to evaluate the validity of the 'Enterprise Health Promotion Index', a tool for assessing health promotion activities of worksite developed by the Ministry of Employment and Labor and the Korea Occupational Safety and Health Agency. Methods: This is designed a methodological study that evaluates the validity of the Enterprise Health Promotion Index. For this study, a questionnaire survey was conducted for the workplace health professional and safety professional, and a total of 297 data were extracted as final data. We developed the informal health promotion needs and activity measurement tools. The correlation coefficient between the score of the enterprise health promotion index and the score of the informal health promotion tool was analyzed for the criterion validity evaluation. Results: The criterion validity of the Enterprise Health Promotion Index and activity index were supported by finding moderate (r=.597) and high (r=.783) correlation coefficient. However, the requirement index has low levels of criterion validity (r=.364). Conclusion: Based on these results, we suggest to improve the utility of the corporate health promotion index by developing user manual, active public relations, and providing briefing sessions.

• Safety and Health at Work
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• v.11 no.3
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• pp.347-352
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• 2020

Background: Low self-esteem can be an issue among health-care workers due to the hierarchical medical system. Health-care workers are also in a high pressure environment that can lead to stress and burnout. This study was conducted to estimate the proportion of health-care workers with low self-esteem, high stress, and burnout and the factors associated with these in a private hospital in Bangalore city. Methods: This cross-sectional study included a random sample of health-care workers of various cadres - doctors, nurses, nursing aides, technicians, and workers in ancillary departments such as laundry, dietary, central sterile supply department, and pharmacy, with probability proportional to size. Rosenberg Scale for Self-esteem, Cohen's Perceived Stress Scale, and Shirom-Melamed Burnout Measure were used as study tools. Results: Among the 306 health-care workers, there were high levels of low self-esteem (48.4%), stress (38.6%), and burnout (48.7%), with the lowest levels being among doctors. Those aged younger than 30 years had significantly lower self-esteem and greater stress. Conclusions: Health-care workers with low self-esteem were nearly thrice more likely to suffer high stress, Odds Ratio (OR) = 2.84 (1.36-5.92), and those who were stressed had more than three times higher chance of experiencing burnout, OR = 3.6 (2.02-6.55). Path analysis showed that low self-esteem among health-care workers had a direct effect on burnout, as well as an indirect effect through stress (mediator variable). This study indicates the need for screening and counseling for low self-esteem, stress, and burnout as part of a periodic medical examination of all cadres of health workers.

• Safety and Health at Work
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• v.8 no.2
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• pp.175-182
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• 2017

Background: With the recent rapid industrialization, occupational safety and health (OSH) has become an important issue in all industrial and human activities. However, incidents of injuries and fatality rates in the Ghanaian industry sector continue to increase. Despite this increase, there is no evidence regarding the element of OSH management in transport activities in Ghanaian industries. Thus, this study aims to examine the perceptions regarding the importance of safety and health in work-related transport activities in Ghanaian industries. Methods: A survey data collection technique was used to gather information on best safety practices over a 5-month period. We randomly selected 298 respondents from industries to answer structured questionnaires. The respondents included drivers, transport managers, and safety engineers. Standard multiple regression model and Pearson product-movement correlation were used to performed the analysis. Results: The result shows that for interventions to improve safety and health, concentration has been on drivers' safety practice with less attention to safe driving environments and vehicle usage. Additionally, the respondents are aware of the importance of OSH in transport activities, but the level of integration does not measure up to the standard to reduce operational accidents and injuries. Finally, strong commitment to changing unsafe practices at all levels of operations appears to be the effective way to improve safety situations. Conclusion: OSH culture is not fully complied in industries transport activities. This study, therefore, supports the use of safety seminars and training sessions for industry workers responsible for transport operations for better integration of safety standards.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.9
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• pp.841-849
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• 2013

Workers engaged in construction works have been exposed to high levels of noise during their work in tunnels. Noise is one of the major health hazards for employees working in construction sites. The aim of this study is to evaluate the noise levels generating from tunneling equipments such as jumbo drills, backhoes, payloaders, shotcrete machines and service cars. Explosion and turbo fan noises were also monitored. A high precision sound level meter was introduced for measuring LAeq, LAFmax, LAFmin and LCpeak noises in 5 tunneling work sites that were located in Seoul, Kyunggi-do and Kangwon-do areas with NATM and shield methods. The highest noise was recorded by explosion(151.9 dB LCpeak) followed by jumbo drills of higher than 110 dB(A) LAeq. Backhoe normally generated 90~110 dB(A) LAeq while breaking work of rock showed additional around 5~15 dB(A). Noise exposure levels for payloader and shotcrete machine scored more than 90 dB(A) which might be a source of noise-induced hearing loss. Additional research in revealing noise levels from construction equipments operating in tunneling works may enhance the protection of workers who exposed to noise primarily at the sites.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.2
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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.

• Safety and Health at Work
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• v.12 no.4
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• pp.439-444
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• 2021

Background: In a previous study, we estimated exposure prevalence and the number of workers exposed to carcinogens by industry in Korea. The present study aimed to evaluate the optimal exposure intensity indicators of airborne lead exposure by comparing to blood lead measurements for the future development of the carcinogen exposure intensity database. Methods: Data concerning airborne lead measurements and blood lead levels were collected from nationwide occupational exposure databases, compiled between 2015 and 2016. Summary statistics, including the arithmetic mean (AM), geometric mean (GM), and 95th percentile level (X95) were calculated by industry both for airborne lead and blood lead measurements. Since many measurements were below the limits of detection (LODs), the simple replacement with half of the LOD and maximum likelihood estimation (MLE) methods were used for statistical analysis. For examining the optimal exposure indicator of airborne lead exposure, blood lead levels were used as reference data for subsequent rank correlation analyses. Results: A total of 19,637 airborne lead measurements and 32,848 blood lead measurements were used. In general, simple replacement showed a higher correlation than MLE. The results showed that AM and X95 using simple replacement could be used as optimal exposure intensity indicators, while X95 showed better correlations than AM in industries with 20 or more measurements. Conclusion: Our results showed that AM or X95 could be potential candidates for exposure intensity indicators in the Korean carcinogen exposure database. Especially, X95 is an optimal indicator where there are enough measurements to compute X95 values.

• Safety and Health at Work
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• v.2 no.4
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• pp.348-354
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• 2011

Objectives: This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. A noise spectral analysis was taken to illustrate the spectra of dental devices. Methods: A noise evaluation was performed to measure the noise level at dental clinics and one dental laboratory from May to December 2010. Noise spectral data of dental devices were taken during dental practices at the dental services clinic and at the dental laboratory. A noise dosimeter was set following the Occupational Safety and Health Administration criteria and then attached to the subjects' collar to record personal noise dose exposure during working periods. Results: The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. The differences in working areas and job positions had an influence on the level of noise exposure (p < 0.01). Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ${\pm}$ 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory. Conclusion: Dental personnel are exposed to noise intensities lower than occupational exposure limits. Therefore, these dental personnel may not experience a noise-induced hearing loss.