• Anxiety and mood
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• v.16 no.1
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• pp.1-8
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• 2020

Objective : This study aims to examine the association between exposure to suicide events and suicide ideation by analyzing the levels of suicide ideation among the groups with exposure to suicide death, non-suicide death, and no death in their social relationships. Methods : Data were derived from Wave I of the Longitudinal Study of Suicide Survivors' Mental Health. 1,998 adults nationwide selected using a stratified sampling method based on the Korean Census Data, were categorized into 3 groups with exposure to suicidal death, non-suicidal death, and no death. The levels of depression (Brief CES-D), subjective health status, and suicidal ideation (SSI) were measured. To examine the association between exposure to suicide and the level of suicide ideation, multiple regression analysis was used after controlling the socio-demographic and clinical factors including subjective health status and depression. Results : 32% reported their exposure to suicide. Compared to the other groups, the suicide-exposed group's level of depression and suicide ideation were significantly higher but the subjective health status was lower. Multiple regression model revealed that suicide exposure had a statistically significant association with suicidal ideation at p=0.000 even after controlling the clinical characteristics. Conclusion : HThe findings suggest that exposure to suicide is a risk factor for suicidal ideation. In the clinical field, it is necessary to consider patients' experience in exposure to suicide while treating and intervening in suicide-related cases. At the policy level, a mental health system for suicide prevention should consider this risk factor for those exposed to suicide in their family and social relationships.

• Journal of Environmental Health Sciences
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• v.45 no.4
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• pp.370-380
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• 2019

Objective: This study was performed to investigate the distribution of individual exposure characteristics according to an exposure assessment classification for humidifier disinfectant and to identify the factors that influence assessment classification. Methods: We examined the exposure characteristics of 4,482 subjects who applied for the 4-1 and 4-2 assessments of environmental exposure to humidifier disinfectant conducted by the Korea Environmental Industry & Technology Institute (KEITI). Environmental exposure assessment classification was assessed using the following seven criteria: 1) Distance from humidifier to face; 2) Spray direction; 3) Time used, daytime 4) Time used, during sleep; 5) Time used, cumulative; 6) Exposure intensity; and 7) Cumulative exposure level. Each criteria was then classified as 'high' or low'. When participants answered for more than four criteria, exposure assessment was determined as 'definite,' 'probable,' or 'possible' depending on the ratio of 'high' responses. If participants' responses were inconsistent, exposure assessment was listed as 'unlikely.' If participants answered for less than four criteria, exposure assessment was considered 'indeterminate.' Results: For the exposure assessment classes, definite was assigned to 38.5% (1,725 subjects), probable assigned to 32.9% (1,474 subjects), 25.0% (1,122 subjects) were assigned to as possible, unlikely assigned to 0.1% (3 subjects), and indeterminate assigned to 3.5% (158 subjects). Overall, participants who used 'Oxy Ssakssak New Gaseupgi Dangbun,' 'Aekyung Gaseupgi Mate,' 'Homeplus Gaseupgi Chungjungje,' and 'E-Mart Gaseupgi Salgyunje' totaled 2,996, 557, 176, and 162 subjects, respectively. There was a statistical difference in the type of humidifier disinfectant products between high-exposed and low-exposed participants. Based on the assessment criteria of humidifier disinfectant exposure, subjects were likely to be in the highly exposed classes (definite and probable) when the subjects were exposed 1) for more than ten hours per day and 2) for more than four hours at night 3) when the total cumulative exposure time was higher than the average, 4) when the direction of humidifier spray was toward the face, 5) when the respiratory position was less than 1 meter of distance from the humidifier, 6) when the concentration of indoor contaminants (ug/m3) was higher than the average exposure intensity, and 7) when overall exposure level ($ug/m3^*hr$) was higher than the average exposure level. Conclusion: This study suggests that each exposure assessment criteria was able to appropriately estimate cumulative exposure levels.

• East Asian Journal of Business Economics (EAJBE)
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• v.6 no.4
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• pp.1-12
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• 2018

Purpose - This paper tests the effect of the structure of manufacturing and marketing subsidiary network on FX exposure of Korean MNEs. Furthermore, the moderating effect of pass-through ability on the relationship between the subsidiary network and FX exposure is explored. Research design and methodology - This study utilizes a sample of 309 Korean MNEs constructed from database offered by KOTRA and KIS-VALUE. Results - As operational flexibility arising from having operations in multiple locations provides an option for firms to tackle FX exposure, greater breadth of manufacturing subsidiary network reduces FX exposure, and greater depth increases FX exposure. However, both the breadth and depth of marketing subsidiary network decrease FX exposure due to the firm's higher level of market presence and knowledge to devise an appropriate marketing strategy that can buffer adverse exchange rate movement. Such an effect is intensified when MNE's have FX exposure pass-through ability stemming from differentiated good. Conclusions - Empirical findings suggest that types and structure of Korean MNEs' foreign subsidiary network are closely related to the level of FX exposure they are experiencing. Also, they can utilize marketing subsidiary network more efficiently when having a higher R&D intensity.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.27-35
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• 2005

This study was carried out to evaluate the characteristics of petroleum refinery workers' exposure to organic solvents. Exposure assessment was conducted by full shift-based long term personal sampling(TWA-P) and task-based short term personal sampling(STEL-P) strategy. Major organic solvents that workers can be exposed are various, varying from C3~C12, and this study focused on 11 kinds including benzene, considering toxicity and concentration level. In comparison with two sampling results, STEL-P shows a significant(p<0.001) excess of exposure level rather than TWA-P. As the potential risk index for benzene is calculated as 16, benzene should be set the highest priority for control in petroleum refinery industry. The tasks with the highest benzene exposure level were de-watering(AM;99.8 ppm), draining(AM;19.6ppm), sampling(AM;16.2ppm), and manual gauging(AM;15.02ppm). Petroleum refinery workers' exposure pattern to organic solvents differs by tasks performed, and some task has a high risk of temporary extreme exposure. Therefore, traditional 8-hour TWA sampling strategy have possibility of underestimation of exposure level of workers in petroleum refinery.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.128-136
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• 1995

The purpose of this study is to evaluate the difference of noise level according to noise measuring methods in the noisy working environments. Sound pressure level(SPL), equivalence sound level(Leq) and personal noise exposure dose(Dose) in the fifty-nine unit workplaces of the twenty-eight industries were measured and relating factors which were affected noise level were investigated. The results were as follows ; 1. The noise levels were $88.70{\pm}5.68dB(A)$ by SPL, $89.07{\pm}5.41dB(A)$ by Leq and $89.07{\pm}5.69$ by Dose. The differences of noise levels by three measuring methods were statistically significant(P<0.001) by repeated measure ANOV A. 2. Comparing with noise levels by general classes of noise exposure, noise levels of continuous noise were $89.14{\pm}5.19dB(A)$ by SPL, $89.45{\pm}4.65dB(A)$ by Leq and $90.04{\pm}5.09$ by Dose. Noise levels of intermittent noise were $87.90{\pm}6.52dB(A)$ by SPL, $88.40{\pm}6.63dB(A)$ by Leq and $90.10{\pm}6.80$ by Dose. The differences noise level of noise measuring methods by general classese of noise exposure were statistically not significant by repeated measure ANOV A. 3. Interaction between general classese of noise exposure and noise measuring methods for noise level was not statistically significant by repeated measure ANOVA. And the noise level by noise measuring methods were statistically significant by repeated measure ANOV A(P<.001) 4. Comparing with noise levels by unit workplace size, noise levels of large unit workplace were $90.73{\pm}5.87dB(A)$ by SPL, $91.32{\pm}5.50dB(A)$ by Leq and $91.82{\pm}6.06$ by Dose and noise levels of middle unit workplace were $88.31{\pm}5.26dB(A)$ by SPL, $88.41{\pm}4.83dB(A)$ by Leq and $89.69{\pm}5.05$ by Dose. And noise levels of small unit workplace were $94.89{\pm}4.10dB(A)$ by SPL, $85.35{\pm}4.11dB(A)$ by Leq and $86.87{\pm}4.98$ by Dose. The noise level differences of noise measuring methods by unit workplace size were statistically significant by repeated measure ANOV A(P<.05). 5. The noise level by noise measuring methods were statistically significant by repeated measure ANOV A(P<.001). But Interaction between workplace size and noise level measuring methods for noise level was not statistically significant by repeated measure ANOVA. According to the above results, there was a difference of the noise level among the three measuring methods. Therefore we must use the personal noise exposure dose using by noise dose meter, possible, to prvent occupational hearing loss in noisy working environment.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.107-114
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• 2012

Purpose: Unlike the existing linear accelerator with photon, proton therapy produces a number of second radiation due to the kinds of nuclide including neutron that is produced from the interaction with matter, and more attention must be paid on the exposure level of radiation workers for this reason. Therefore, thermoluminescence dosimeter (TLD) that is being widely used to measure radiation was utilized to analyze the exposure level of the radiation workers and propose a basic data about the radiation exposure level during the proton therapy. Materials and Methods: The subjects were radiation workers who worked at the proton therapy center of National Cancer Center and TLD Badge was used to compare the measured data of exposure level. In order to check the dispersion of exposure dose on body parts from the second radiation coming out surrounding the beam line of proton, TLD (width and length: 3 mm each) was attached to on the body spots (lateral canthi, neck, nipples, umbilicus, back, wrists) and retained them for 8 working hours, and the average data was obtained after measuring them for 80 hours. Moreover, in order to look into the dispersion of spatial exposure in the treatment room, TLD was attached on the snout, PPS (Patient Positioning System), Pendant, block closet, DIPS (Digital Image Positioning System), Console, doors and measured its exposure dose level during the working hours per day. Results: As a result of measuring exposure level of TLD Badge of radiation workers, quarterly average was 0.174 mSv, yearly average was 0.543 mSv, and after measuring the exposure level of body spots, it showed that the highest exposed body spot was neck and the lowest exposed body spot was back (the middle point of a line connecting both scapula superior angles). Investigation into the spatial exposure according to the workers' movement revealed that the exposure level was highest near the snout and as the distance becomes distant, it went lower. Conclusion: Even a small amount of exposure will eventually increase cumulative dose and exposure dose on a specific body part can bring health risks if one works in a same location for a long period. Therefore, radiation workers must thoroughly manage exposure dose and try their best to minimize it according to ALARA (As Low As Reasonably Achievable) as the International Commission on Radiological Protection (ICRP) recommends.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.87-98
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• 1999

The objectives of this study were to evaluate exposures to airborne methylene chloride and postshift carboxyhemoglobin (COHb) in blood of workers engaged in processes using blowing or cleaning agents, and to investigate correlation between methylene chloride concentrations and the blood COHb levels of workers. The geometric mean (GM) of workers' exposures (8 hour-time weighted averages, TWA) to airborne methylene chloride during cleaning molds using rags wetted with the solvent in the manufacture of flexible polyurethane foam (GM = 61.4 ppm), during operating the dip tank for cleaning molds in the manufacture of lens (GM = 61.0 ppm), and during cleaning the blowing nozzles by spraying the solvent in the manufacture of shoes (GM = 117.2 ppm) were exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value ($TLV^{(R)}$)-Time Weighted Average (TWA) (50 ppm). The COHb levels were significantly different among groups (p<0.05). The average COHh levels in blood of non-smoking workers were 2.0% in. low-level (<50 ppm) exposure group, and 3.9 % in high-level (>50ppm) exposure group. The average COHb levels in smoking workers were 3.1% in low-level exposure group, and 4.8% in high-level exposure group. The blood COHb levels of no-exposed workers to methylene chloride were 1.8% in non-smoking group, and 2.8% in smoking group. It was found that the COHb level dependeds on the methylene chloride concentration and smoking habit, and was highly correlated with methylene chloride concentration in air. The correlation coefficient was 0.81 among non-smoking workers. The estimated COHb level (3.6%) and 95% upper confidence limit (4.0%) corresponding to TLV-TWA of methylene chloride exceeded the current ACGIH Biological Exposure Index (COHb 3.5%) for carbon monoxide. The estimated COHb level (5.4%) at 100 ppm exceeded the standard (5%) recommended by National Institute for Occupational Safety and Health (NIOSH) for preventing adverse cardiovascular effect. The estimated COHb value and 95% upper confidence limit at 25 ppm of the Occupational Safety and Health. Adminstration (OSHA) Permissible Exposure Limit-TWA (PEL-TWA) were 2.6% and 3.0%, respectively. It is suggested that COHb in blood be kept below 3.0% to comply with OSHA PEL-TWA.

• Safety and Health at Work
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• v.1 no.1
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• pp.51-60
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• 2010

Objectives: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process. Methods: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1 hr) samples were taken during TAs. TA was classified into three stages: shut-down, maintenance and start-up. All works were classified into 12 occupation categories. Results: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120 ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855 ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1 ppm) and the short-term exposure limit (STEL-OEL, 5 ppm) were 4.1% (20 samples of 488) and 6.0% (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05). Conclusion: These findings suggest that the periodic work environment must be assessed during non-routine works such as TA.

• The Korean Journal of Community Living Science
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• v.28 no.3
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• pp.391-401
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• 2017

This study was conducted to evaluate the relationships between exposure level to pyrethroid pesticide and wearing of protective equipment in 194 Chung-nam orchard male farmers. The urinary metabolites of pyrethroid pesticides, including Cis, Trans, DBCA, and 3-PBA, were analyzed by GC/MSD. As a result of this study, the detection rate and exposure level of 3-PBA was the highest among pyrethroid metabolites discovered by orchard farmers. As a result of analyzing the actual conditions of wearing protective equipment by the subjects of this study, the rate of agricultural farmers who wore four pieces of protective equipment compared to agricultural farmers wearing a single piece of protective clothing was as high as 35.1%. Pyrethroid exposure levels were low when farmers wore more personal protective equipment (PPE). In conclusion, training with regards to pesticide hazards and protective equipment for farmers who spray pesticides will help reduce pesticide exposure levels.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.1
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• pp.21-26
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• 2019

Objective: The aim of this study is to analyze an excess trend for domestic permissible exposure limit of trichloroethylene based on previous literature review. Materials and Methods: The research object is a trichloroethylene among 13 chemical substances regulated with PEL(Permissible Exposure Limit) in Occupational Safety and Health Act. The information utilized from this study is the work environment measurement data from 2004 to 2013. The highest level among concentration data measured at various workplaces was selected as a representative value through data process. N.D. (Not Detected) data was considered as 1/2 of LOD(Limit Of Detection). Results: Among work environment measurement data between 2004 and 2013, the highest number of excess workplace and excess rate(24 sites & 1.15%) was observed in 2008's data when applying the PEL(50 ppm) of trichloroethylene. When they are compared with the ACGIH's TLV-TWA(10 ppm), 2008's data showed the highest number of excess workplace and excess rate(175 sites & 8.37%). The number of excess workplace and excess rate related to PEL of trichloroethylene showed increase trend in 2005 but tended to decrease after 2008. Conclusions: Based on the results obtained from this study, the exposure level of trichloroethylene in case of domestic workers is not considered as a safe phase regardless of the year of work environment measurement year. Thus, a strictly preventive management in workplace should be provided for reducing exposure level of trichloroethylene.