• Safety and Health at Work
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• v.9 no.2
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• pp.149-158
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• 2018

Background: Work comfort studies have been extensively conducted, especially in the underground and meteorological fields resulting in an avalanche of recommendations for their evaluation. Nevertheless, no known or universally accepted model for comprehensively assessing the thermal work condition of the underground mine environment is currently available. Current literature presents several methods and techniques, but none of these can expansively assess the underground mine environment since most methods consider only one or a few defined factors and neglect others. Some are specifically formulated for the built and meteorological climates, thus making them unsuitable to accurately assess the climatic conditions in underground development and production workings. Methods: This paper presents a series of sensitivity analyses to assess the impact of environmental parameters and metabolic rate on the thermal comfort for underground mining applications. An approach was developed in the form of a "comfort model" which applied comfort parameters to extensively assess the climatic conditions in the deep, hot, and humid underground mines. Results: Simulation analysis predicted comfort limits in the form of required sweat rate and maximum skin wettedness. Tolerable worker exposure times to minimize thermal strain due to dehydration are predicted. Conclusion: The analysis determined the optimal air velocity for thermal comfort to be 1.5 m/s. The results also identified humidity to contribute more to deviations from thermal comfort than other comfort parameters. It is expected that this new approach will significantly help in managing heat stress issues in underground mines and thus improve productivity, safety, and health.

• Journal of Environmental Health Sciences
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• v.49 no.2
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• pp.78-88
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• 2023

Background: Exposure to volatile organic compounds (VOCs) can have acute and chronic health effects on human beings in general and in working environments. In particular, VOCs are often emitted in large quantities in industrial settings. In such circumstances, there is a need to improve the indoor air quality at workplaces. Objectives: The purposes of this study were to verify the effectiveness of air cleaning devices in workplaces and provide alternative solutions for improving working environments. Methods: Personal exposure and area level of VOCs for workers were evaluated in a car-part adhesive process before and after installing an air cleaning device with a TiO₂-coated filter. Passive samplers and direct reading instruments were used to collect and analyze the VOCs, and the removal efficiency and improvement of air quality were evaluated. We also calculated the exposure index (EI) to assess the risk level in the workplace. Results: The removal efficiency for VOCs through the installation of the air cleaning device was approximately 26.9~69.0% as determined by the concentration levels before and after installation. The measured substances did not exceed the exposure limits for the work environment and the EI was less than 1. However, carcinogenic substances such as benzene, formaldehyde, carbon tetrachloride, and trichloroethylene were detected. Conclusions: The application of an air cleaning device can be a solution for controlling the indoor air quality in a workplace, particularly in cases where ventilation systems cannot be installed due to process limitations.

• The Korean Journal of Applied Statistics
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• v.6 no.2
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• pp.201-215
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• 1993

The health status of workers in a foundry was analyzed in a study which consisted of evaluations of respiratory health together with environmental measurements. The results from environmental measurements showed values exceeding permissible exposure limits. A t-test was done with log transformed and untransformed data to examine the statistical significance for the noncompliance with exposure standards. For the analysis of categorical health outcomes, $\chi$-square test with 2 $\times$ 2 tables and logistic regression analysis were employed. For continuous variables, multiple linear regression was done against assessed risk factors. Pros and cons of different parameters in the compliance (or noncompliance) testing were presented. Respiratory function did not show any relation with occupational exposures, which may be due to the healthy worker effects. Strategies for controlling time dependent covariates were discussed in relation to the healthy worker effect. The scope of statistical analysis in occupational health studies is still limited in Korea without a suitable external comparison group such as credible vital statistics for the whole nation. Internal comparisons between different exposure status often result in unstable estimates of effect, and proportional morbidity study is discussed as an alternative potential research tool.

• Journal of Radiation Industry
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• v.17 no.1
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• pp.61-67
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• 2023

A Study on the Introduction of Dose Constraints for Occupational Exposures: Focusing on Experts' Opinions by Field of Radiation Industry. The International Commission on Radiological Protection suggests Justification, Optimization, and Dose Limits as the three principles of radiological protection, among which, as a means of protection optimization, ICRP 103 recommends to set dose constraints. In this study, opinions are collected from experts in each category of radiation industries for stakeholder participation to qualify dose constraints. A guidance and questionnaire for analyzing the dose constraints have been developed for their collection, and opinions were collected from radiation protection experts in selected categories. 20 out of 22 experts, consisted with 91%, have assessed the dose constraints setting is necessary, and 2 experts, consisted with 9%, assessed it is unnecessary. The average of dose constraint presented by experts for RI production institutions is to be the highest level of 15.3 mSv, and light-water reactors (14.6 mSv), non-destructive inspection (14.4 mSv), heavy-water reactor and medical institutes (13.9mSv) is to be above the overall average dose constraint. In case of public institutions, the average dose constraint is to be 8.6mSv, and research institutions (8.8mSv), educational institutions (9.6 mSv), waste disposal sites (9.7 mSv), and general industries (10.6 mSv) are resulted to below the overall average dose constraint. As for the means of setting dose constraints, 8 experts out of 22 suggested setting dose constraints for each specific industry or task. And, 5 experts especially suggest setting dose constraints for the specific groups with relatively high exposure, such as workers with above the record levels. As a countermeasure for workers who exceed the dose constraints, 15 experts out of 22 expressed that the cause analyses for them and preparation for a plan of reducing them are necessary.

• Journal of Environmental Health Sciences
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• v.38 no.6
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• pp.561-567
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• 2012

Objectives: Parabens are widely used as antimicrobial agents in pharmaceuticals and cosmetics as well as by the food industry. Parabens have been reported to show weak estrogenic activity and be related to health effects such as allergic reactions and skin and breast cancer. We evaluated an online solid phase extraction (SPE) method coupled with LC-MS/MS technique using free and conjugated parent parabens in human urine for assessing human exposure to parabens. Methods: We employed LC/MS/MS through online solid phase extraction and column-switching techniques and analyzed free and conjugated parabens as biomarkers of human exposure. Four major parabens, methyl-paraben (MP), ethyl-paraben (EP), propyl-paraben (PP) and butyl-paraben (BP), were analyzed. Method validation was performed by sensitivity, accuracy, precision and comparison of the results of online SPE with offline SPE. Results: The limits of detection (LOD) were in the range of 0.2-2 ng/mL, and actual limits of quantification (LOQ) were in the range of 0.7-6 ng/mL urine, depending upon the compound. Accuracy was in the range of 98.3-106.4%, and precision was in the range of 1.3-8.7% (CV) depending upon the compound. We found a good correlation between the results of analysis by online SPE method and that by off-line SPE method. Conclusions: The online SPE method showed proper LOD and validated accuracy, precision and good correlation with the offline method for analyzing parabens in urine.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.423-430
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• 2021

In order to evaluate the fire risk and fire risk rating of wood for construction materials, this study focused on fire performance index-III (FPI-III), fire growth index-III (FGI-III), and fire risk index-IV (FRI-IV) according to Chung's equations-III and -IV. Western red cedar, needle fir, ash, and maple were used as the specimens. The fire characteristics were investigated using a cone calorimeter (ISO 5660-1) equipment on the specimen. The FPI-III measured after the combustion reaction was 0.86 to 12.77 based on polymethylmethacrylate (PMMA). The FGI-III was found to be 0.63 to 5.26 based on PMMA. The fire rating according to the FRI-IV, which is the fire rating index, was 0.05 to 6.12, and the western red cedar was 122.4 times higher than that of the maple. The fire risk rating according to the FRI-IV increased in the order of maple, ash, needle fir, PMMA and western red cedar. The CO peak concentration of all specimens was measured as 103 to 162 ppm, and it was 2.1 to 3.2 times higher than 50 ppm, the permissible exposure limits of the US occupational safety and health administration. Materials such as western red cedar, which have a low bulk density and contain a large amount of volatile organic substances, have a low FPI-III and a high FGI-III, so they have a high fire risk rating.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.17-27
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• 1996

This study was designed to survey exposure levels of formaldehyde among workplaces in some plywood industries and to compare three sampling methods including the impinger method(IM, NIOSH method No. 3500), the solid sorbent tube method(SS, NIOSH method No. 2541), and the passive bubbler monitor method(PB, SKC). The survey was conducted in seven particle board manufacturing factories, two resin manufacturing factories and two plywood manufacturing factories in Incheon area during the period from March 6 to April 20, 1995. The workplaces included were the hot/cold press, the roller/spreader, the soaking/drying, and the reaction/mixing areas. The results were as follows; 1. The average(GM, GSD) concentrations of formaldehyde by sampling methods were 0.11(4.43) ppm by IM, 0.27(2.03) ppm by SS, and 0.29(2.04) ppm by PB, respectively. The concentrations by 1M method were statistically very significantly lower than those of SS and PB methods, particularly at low air borne concentrations of formaldehyde (p<0.001). 2. The area average concentrations of formaldehyde by workplaces measured with PB bubblers were 0.23(2.08) ppm from the press, 0.23(1.77) ppm from the spreader, 0.24(1.51) ppm from the soaking, and 0.46(1.96) ppm from the reaction areas, respectively. The personal average concentrations of formaldehyde by workplaces measured with PB bubblers were 0.30(1.77) ppm from the press, 0.33(1.54) ppm from the spreader, 0.36(1.46) ppm from the soaking, and 0.84(1.19) ppm from the reaction areas, respectively. 3. No statistically significant differences of formaldehyde concentrations among workplaces except the reaction area(p<0.001) were found. 4. Formaldehyde concentrations from personal samples were higher than those of from area sam pies in all workplaces studied. But no statistically significant differences of formaldehyde concentrations both area and personal samples were found. In conclusion, this study found that although formaldehyde concentrations in some plywood industries in Incheon area were below the regulatory limit of 1 ppm, they were over the limits recommended by NIOSH and ACGIH. This study also suggests that the impinger method may underestimate true formaldehyde concentrations. It implies that there will be more workplaces not meeting current regulatory limit if either the solid sorbent or passive bubbler methods were used instead of the impinger method. It is suggested that passive monitors will be a reasonable alternative for area and personal sampling of formaldehyde if the accuracy and validity of passive monitors be verified before use.

• Safety and Health at Work
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• v.8 no.3
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• pp.237-245
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• 2017

Background: Solar furnaces are used worldwide to conduct experiments to demonstrate the feasibility of solar-chemical processes with the aid of concentrated sunlight, or to qualify high temperature-resistant components. In recent years, high-flux solar simulators (HFSSs) based on short-arc xenon lamps are more frequently used. The emitted spectrum is very similar to natural sunlight but with dangerous portions of ultraviolet light as well. Due to special benefits of solar simulators the increase of construction activity for HFSS can be observed worldwide. Hence, it is quite important to protect employees against serious injuries caused by ultraviolet radiation (UVR) in a range of 100 nm to 400 nm. Methods: The UV measurements were made at the German Aerospace Center (DLR), Cologne and Paul-Scherrer-Institute (PSI), Switzerland, during normal operations of the HFSS, with a high-precision UV-A/B radiometer using different experiment setups at different power levels. Thus, the measurement results represent UV emissions which are typical when operating a HFSS. Therefore, the biological effects on people exposed to UVR was investigated systematically to identify the existing hazard potential. Results: It should be noted that the permissible workplace exposure limits for UV emissions significantly exceeded after a few seconds. One critical value was strongly exceeded by a factor of 770. Conclusion: The prevention of emissions must first and foremost be carried out by structural measures. Furthermore, unambiguous protocols have to be defined and compliance must be monitored. For short-term activities in the hazard area, measures for the protection of eyes and skin must be taken.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.446-464
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• 2015

Objectives: This study was conducted to evaluate the task-specific hazards of chemicals used by nail technicians in Daegu Metropolitan City. Materials: A total of 30 nail shops located in Daegu City were surveyed to investigate the major tasks and practices performed by nail technicians and the ingredients listed in nail care products used in shops. We also collected instructions for use and material safety data sheets(MSDSs) of nail care products and compared CAS Nos. of ingredients with the lists of chemicals regulated by the Industrial Safety and Health Act(ISHA) and Chemical Substances Control Act(CSCA). Results: A total of 125 chemical ingredients were found in 468 nail care products used at the 30 nail shops. The most frequently found ingredients were ethyl acetate(72%), followed by n-butyl acetate(71.8%), isopropanol(56%), benzophenone(51.1%), nitrocellulose(46.4%) and ethanol(45.3%). Comparing six tasks, the task of manicuring used the most products at 222 products containing 91 ingredients. Among the 125 ingredients, there are 31 chemicals with occupational exposure limits(OEL) designated by the Ministry of Employment and Labor(MoEL), eight categorized as carcinogens, one mutagen and two reproductive toxic chemicals. In terms of carcinogens, formaldehyde was identified as the only confirmed human carcinogen(1A). We found that there was one chemical with a permissible limit, one special management substance, 18 workplace monitoring substances and ten special health diagnosis substances regulated by ISHA. For CSCA, nine poisonous substances, six substances requiring preparation for accidents and one restricted substance were identified. Conclusions: Based on these findings, formaldehyde was identified as one of the chemicals that should most strictly be controlled for the protection of the health of nail technicians and customers. At the same time, it is necessary to distribute materials with detailed hazardous information of nail care products for nail shop technicians.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.442-451
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• 2019

Objectives: The aim of this study was to review the reduction methods for ammonia (NH₃) and hydrogen sulfide (H₂S) exposure in livestock. Methods: By reviewing domestic and international research reports from Korea and China, reducing ammonia and hydrogen sulfide in livestock pens was analyzed in terms of ventilation, deodorant, and feed additives. In addition, exposure limits in Korea and China were examined through a comparison between 'TLV-TWA and STEL under the Industrial Safety and Health Act in Korea' and 'Management Standards for Air of Livestock Pens in China'. Results and Discussion: In order to effectively control hazardous gases and odors in livestock pens, the enhancement of natural ventilation or the addition of ventilation fans at the pollution source are being examined. Deodorants are used as adsorbents or masking deodorants. Additives to feed were zeolite powder, FeSO₄·7H₂O, enzymes, and microbial preparations. Use of feed additives was low-cost and had significant effects compared to other methods. Zeolite was the most commonly used in feed additive in Chinese cases and proved to be low-cost and effective for reducing harmful gases. Enzyme preparations were shown to stimulate the growth of livestock, but were expensive. Conclusions: This study reviewed and examined domestic and international research papers in Korea and China for reducing ammonia and hydrogen sulfide concentrations in livestock pens. More diverse research and the development of feed additives are needed.