• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.24.1-24.15
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• 2023

Background: The construction workers are vulnerable to fatigue due to high physical workload. This study aimed to investigate the relationship between overwork and heart rate in construction workers and propose a scheme to prevent overwork in advance. Methods: We measured the heart rates of construction workers at a construction site of a residential and commercial complex in Seoul from August to October 2021 and develop an index that monitors overwork in real-time. A total of 66 Korean workers participated in the study, wearing real-time heart rate monitoring equipment. The relative heart rate (RHR) was calculated using the minimum and maximum heart rates, and the maximum acceptable working time (MAWT) was estimated using RHR to calculate the workload. The overwork index (OI) was defined as the cumulative workload evaluated with the MAWT. An appropriate scenario line (PSL) was set as an index that can be compared to the OI to evaluate the degree of overwork in real-time. The excess overwork index (EOI) was evaluated in real-time during work performance using the difference between the OI and the PSL. The EOI value was used to perform receiver operating characteristic (ROC) curve analysis to find the optimal cut-off value for classification of overwork state. Results: Of the 60 participants analyzed, 28 (46.7%) were classified as the overwork group based on their RHR. ROC curve analysis showed that the EOI was a good predictor of overwork, with an area under the curve of 0.824. The optimal cut-off values ranged from 21.8% to 24.0% depending on the method used to determine the cut-off point. Conclusion: The EOI showed promising results as a predictive tool to assess overwork in real-time using heart rate monitoring and calculation through MAWT. Further research is needed to assess physical workload accurately and determine cut-off values across industries.

• 대한예방의학회:학술대회논문집
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• 1994.02a
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• pp.402-403
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• 1994

There are three different approaches to chemical risk assessment which will be considered in this paper. The U.S. Environmental Protection Agency(EPA) Cancer Risk Assessment includes some of the approaches used by the International Agency for Research on Cancer (IARC). The Agency for Toxic Substances and Disease Registry (ATSDR) effort is an evaluated database approach similar to that used in the National Institute for Occupational Safety and Health (NIOSH) Criteria Documents and in the documentations prepared by the Occupational Safety and Health Administration (OSHA) for the Permissible Exposure Limits (PELs) and those of the American Conference of Governmental Industrial Hygienists (ACGIH) for the Threshold Limit Values (TLVs). A third approach is used by the Committee on Toxicology.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.55-61
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• 2013

We undertook the quantitative evaluations of Industrial Accident Prevention Program (IAPP). The six parameters, such as relevance, efficiency, consistency, sustainability, effectiveness, coherence, were chosen by expert plenary sessions. Two stage of Analytic Hierarchy Process were used to determine the weighted value of assessment criteria. This expert plenary suggests that the six parameters and its weight values are useful for quantitative evaluations of IAPP. Additional researches regarding the real world application of this assessment tool should be initiated.

• Safety and Health at Work
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• v.12 no.2
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• pp.230-237
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• 2021

Background: Noise-induced hearing loss is a well-known occupational disease that affects many fish harvesters from many fisheries worldwide, whose risk factor is prolonged exposure to hazardous noise levels. To date, academic research activities and regulatory bodies have not provided any comparative analysis among the existing methods to assess noise exposure levels of fish harvesters. This paper provides a comparison of four relevant assessment methods of noise exposure, examining the results of a measurement campaign performed onboard small fishing vessels from Newfoundland and Labrador. Methods: We traveled onboard 11 vessels engaged in multiple fisheries from Newfoundland and Labrador and performed extensive noise exposure surveys using the simplified International Maritime Organization method, the full-day measurement method, and the two methods provided by ISO 9612:2009, the task-based method and job-based method (JBM). Results: The results showed that the four methods yield similar values when the noise components are dominated by the engine and auxiliaries (steady-state sources); when noise components are dominated by the fishing gear, task-based method and the simplified International Maritime Organization method estimates are less accurate than JBM, using full-day measurements as baseline. Conclusion: The JBM better assesses noise exposure in small-scale fisheries, where noise exposure has significant variance and uncertainties on the exposure levels are higher.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.1
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• pp.63-69
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• 2010

This study was conducted to compare the concentration of various air contaminants in nine different laboratories during routine activities. Volatile organic compounds (VOC) were sampled and analyzed using NIOSH Method 1500 and asbestos fibers were sampled and analyzed using NIOSH Method 9002 and 7400. Detectable levels of acetone, toluene and ethanol were found in all the laboratories and xylene and n-hexane were detected in eight of the nine laboratories. All the VOC concentrations were well below the Korean Ministry of Labor's Exposure Limit and American Conference of Governmental Industrial Hygienists' (ACGIH) Threshold Limit Values (TLVs). Total VOC concentrations at the university laboratories were significantly higher than those at governmental agency laboratories. Airborne fiber concentrations were below 0.01 fibers/cc, while the concentration of chrysotile was 2% in insulation materials sprayed on the ceiling of one laboratory. While all the governmental agency laboratories (n=4) had fume hoods, two out of the five university laboratories did not have fume hoods. The capture velocity of half of the fume hoods were below the maintenance standard(0.4 m/sec). In conclusion, the study suggests that the current controls in place at both university and government agency laboratories are not sufficient in limiting exposure to harmful chemicals to non-detectable levels, though they appear to be adequate in protecting workers to levels below applicable occupational exposure limits. The study also suggests that researchers working in university laboratories may be exposed to greater levels of contaminant than those working in government agency laboratories.

• Toxicological Research
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• v.32 no.4
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• pp.337-343
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• 2016

We determined the toxicity of mixtures of ethyl acetate (EA), isopropyl alcohol (IPA), methyl ethyl ketone (MEK), toluene (TOL) and xylene (XYL) with half-maximal effective concentration ($EC_{50}$) values obtained using human hepatocytes cells. According to these data, quantitative property-activity relationships (QPAR) models were successfully proposed to predict the toxicity of mixtures by multiple linear regressions (MLR). The leave-one-out cross validation method was used to find the best subsets of descriptors in the learning methods. Significant differences in physico-chemical properties such as boiling point (BP), specific gravity (SG), Reid vapor pressure (rVP) and flash point (FP) were observed between the single substances and the mixtures. The $EC_{50}$ of the mixture of EA and IPA was significantly lower than that of contained TOL and XYL. The mixture toxicity was related to the mixing ratio of MEK, TOL and XYL (MLR equation $EC_{50}=3.3081-2.5018{\times}TOL-3.2595{\times}XYL-12.6596{\times}MEK{\times}XYL$), as well as to BP, SG, VP and FP (MLR equation $EC_{50}=1.3424+6.2250{\times}FP-7.1198{\times}SG{\times}FP-0.03013{\times}rVP{\times}FP$). These results suggest that QPAR-based models could accurately predict the toxicity of polar and nonpolar mixtures used in rotogravure printing industries.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.131-134
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• 2008

In this study, the lower detonation limits(LDL) and the upper detonation limits(UDL) of the flammable substances predicted with the appropriate use of the heat of combustion and the stoichiometric coefficient. The values calculated by the proposed equations were a good agreement with literature data within a few percent. From a given results, It is to be hoped that this methodology will contribute to the estimation of the detonation limits of for other flammable substances.

• Safety and Health at Work
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• v.5 no.2
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• pp.91-96
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• 2014

Background: Chronic obstructive pulmonary disease (COPD) is an important cause of occupational mortality in miners exposed to coal mine dust. Although the inflammatory mediators involved in COPD have not been defined, many studies have shown that inflammatory mediators such as reactive oxygen and nitrogen species are involved in orchestrating the complex inflammatory process in COPD. Methods: To investigate the relevance of exhaled biomarkers of oxidative and nitrosative stress in participants with COPD, we determined the levels of hydrogen peroxide, malondialdehyde (MDA), and 3-nitrotyrosine (3-NT) in exhaled breath condensate (EBC) in 90 retired elderly coal miners (53 non-COPD and 37 COPD participants). Results: Mean levels of MDA (4.64 nMvs. 6.46 nM, p = 0.005) and 3-NT (3.51 nMvs. 5.50 nM, p = 0.039) in EBC were significantly higher in participants with COPD. The median level of MDA did show statistical difference among the COPD severities (p = 0.017), and the area under the receiver operating characteristic curve forMDA (0.67) for the diagnostic discrimination of COPD indicated the biomarker. The optimal cutoff values were 5.34 nM (64.9% sensitivity and 64.2% specificity) and 5.58 nM (62.2% sensitivity and 62.3% specificity) forMDA and 3-NT, respectively. The results suggest that high levels ofMDA and 3-NT in EBC are associated with COPD in retired elderly miners. Conclusion: These results showed that the elevated levels of EBC MDA and EBC 3-NT in individuals with COPD are biomarkers of oxidative or nitrosative stress.

• Journal of the Ergonomics Society of Korea
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• v.27 no.3
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• pp.81-92
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• 2008

Musculoskeletal disorder (MSD) problems have been increasingly reported in hospital sector but the problems were not addressed with respect to holistic aspects of the target population in Korea. Often, it is required to understand how MSD symptoms are associated with factors such as personal, work environmental and psychosocial stressors. To examine features of association between sets of MSD symptoms and the factors, a questionnaire survey was conducted in a university hospital. A 140-item questionnaire was developed and used for collecting information including factors (e.g., job/occupation, task/activity, job stress) and MSD symptoms. A total of 1,091 workers (male 23.7% and female 76.3%) were finally determined for data analyses. Prevalence rate for the whole body was 72% and, among body parts, the highest was 48.7% for the shoulder, followed by 34.6%(the low back), 32.7%(the leg/foot), 27.9%(the neck), 26.7%(the wrist) and 12%(the elbow). The symptoms were significantly different by job/occupational variable in each of all body parts except the neck. The symptoms were very significantly different by task/activity variables in each of all body parts while those symptoms were significantly different by psychosocial variables, depending on body part and gender. In the logistic regression analyses performed for MSD symptoms by body part and each of 3 factors, odds ratio values varied, ranging from 0.7 to 3.3. The controls for reducing the symptoms were discussed on the basis of the findings. The results show that the MSD symptoms can remarkably vary by the factors and, in particular, can be highly differential for the task/activity factor. This study suggests that MSD symptom features be examined by using various factors and then a higher differential factor be primarily utilized for controling MSD symptoms in general industry including hospital settings.

• Journal of Preventive Medicine and Public Health
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• v.37 no.3
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• pp.225-231
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• 2004

Objectives : This study was performed to examine the influence of smoking on the blood cadmium concentration in university students. Methods : The study included 300 university students. A questionnaire interview was used to collect data. The urine cotinine and blood cadmium levels were measured as biological exposure indices. The data were analyzed using t-tests ANOVA and ANCOVA. Results : The median value of blood cadmium concentration was equal in both males and females ($0.8{\mu}g/l$). This level was relatively low in comparison with the reference value suggested by WHO (2001). ANCOVA showed that smoking related variables, urine cotinine and smoking amount, were significantly associated with the blood cadmium level (P=0.004, 0.015). However, the values with regard to traffic related air pollution were not significantly associated with the blood cadmium level. Conclusions : Smoking is an important source of nonoccupational cadmium exposure in young people. The Blood cadmium level is at least 10% higher in active smokers than in passive or nonsmokers. The level of urine cotinine can be used as an indicator of non-occupational exposure of respirable cadmium due to smoking, as there is a good correlation bestween smoking amount and the urine cotinine level.