• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.1-18
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• 1999

The purpose of this study was to compare performances of two analytical methods, the OSHA 42 and the NIOSH 5522, of quantifying total isocyanates in air. These methods were compared in terms of accuracy and precision and the detection limits using four(4) spiked samples in each of four(4) concentration levels which ranged from 0.25 to 2.0 times of the ACGIH TLV-TWA. In addition, two methods were used to as sess airborne concentrations of total isocyanates at the following processes including autobody spray painting, furniture spray painting, polyurethane foaming, urethane adhesion, UV coating, and pigment mixing. The results of this study showed that the NIOSH 5522 method was better than the OSHA 42 method in terms of accuracy, precis ion, and detection limit for quantifying airborne total isocyanates. It was also clear that the NIOSH method was capable of detecting not only monomeric but also non-monomeric isocyanates. The results of air concentrations of total isocyanates among processes studied indicate that some processes may exceed the recommended level of isocyanates. In addition, to evaluate toxicological effects of total isocyanates, it is recommended to consider additive effects of isocyanates present in mixtures.

• 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.

• Fire Science and Engineering
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• v.33 no.4
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• pp.28-34
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• 2019

Regardless of the ignition source, the main factors affecting the spread of flames to the human body are combustibles. The sound absorption material, which is the finishing material used in music institutes and karaoke rooms, consists of polyurethane that generates a large amount of toxic gas with a high amount of combustion gases during a fire. Still, the current law does not require the use of impregnated finishing materials for tutoring services with less than 100 users. In this study, the rate of flame diffusion was measured using the MultiRaelite composite gas measuring instrument (target substance VOC, HCHO, SO₂, CO₂, CO, HCN, and NO₂) for the collection of sound-absorbing materials installed in the actual music academy. The results showed that the toxic gas found in this experiment exceeded the allowable concentration of TWA (Time Weighted Average) and STEL (Short Term Exposure Limit). In addition, a comparative combustion test of the general sound absorber and non-combustion sound absorbing materials on the market showed wide differences in ignition and diffusion. Therefore, based on the results of the experiment, private institutes with less than 100 users should be mandated to use non-combustion sound absorbing materials.

• Journal of the Korean Institute of Gas
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• v.25 no.3
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• pp.27-38
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• 2021

We devised the system to automatically shutdown the boiler and to fundamentally block the harmful gases, including carbon monoxide, into the indoor when the exhaust system swerves: (1) The discharge pressure of the exhaust gas decreases when the exhaust pipe is disconnected. The monitoring system of the exhaust pipe is implemented by measuring the output voltage of APS(Air Pressure Sensor) installed to control the amount of combustion air. (2) The operating software was modified so that when the system recognizes the fault condition of a flue pipe, the boiler control unit displays the fault status on the indoor regulator while shutting down the boiler. In accordance with the ventilation facility standards in the "Rules for Building Equipment Standards" by the Ministry of Land, Infrastructure and Transport, experiments were conducted to ventilate indoor air. When carbon monoxide leaked in worst-case scenario, it was possible to prevent poisoning accidents. However, since 2013, the number of indoor air exchange times has been mitigated from 0.7 to 0.5 times per hour. We observed the concentration exceeding TWA 30 ppm occasionally and thus recommend to reinforce this criterion. In conclusion, if the flue pipe fault detection and the indoor air ventilation system are introduced, carbon monoxide poisoning accidents are expected to decrease significantly. Also when the manufacturing and inspection steps, the correct installation and repair are supplemented with the user's attention in missing flue, it will be served to prevent human casualties from carbon monoxide poisoning.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.1
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• pp.47-52
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• 2010

Green tobacco sickness (GTS) is known as an occupational disease among tobacco harvesters, and a form of acute nicotine intoxication by the absorption of nicotine through the skin from the wet green tobacco plant. On the assumption that GTS may occur by inhalation as well as absorption of nicotine, we measured the airborne nicotine concentration in tobacco field and the processing room of tobacco leaves. We measured the airborne nicotine concentrations in the tobacco field and processing room between 13 and 30 July 2008. All sampling and analyses of airborne nicotine were conducted according to the manual of analytic methods of NIOSH 2551, and we sampled 2 times at 11 points in the tobacco field by area sampling. The sampling in the processing room of tobacco leaves was conducted at 3 points, and earlymorning dew was collected from the tobacco by wringing the moisture into specimen bottles. The airborne nicotine concentration [geometric mean (geometric standard deviation)] in the tobacco field in the P.M. was higher [49.2 mg/$m^3$ (1.3)] than the A.M. concentration [43.4 mg/$m^3$ (1.4)]. Similarly, the nicotine concentration in the processing room of tobacco leaves was 224.4 mg/$m^3$ (1.2), and the concentration of nicotine in the dew was 64.7 mg/${\ell}$ (1.7). Based on our results, the airborne nicotine concentration in the tobacco field and the processing room of tobacco leaves were 100 and 400 times higher than the occupational recommended values (TLV-TWA of 0.5 mg/$m^3$), respectively. In the future, it is hoped that epidemiologic studies and environmental measurements will be conducted for GTS which occurs by inhalation of nicotine. If GTS is confirmed to occur by inhalation of nicotine, respiratory and dermal protective equipment must be distributed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.2
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• pp.164-168
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• 2013

Objectives: This study was aimed at the examination of the lead exposure status of smelting process workers in steelmaking using scrap iron. Methods: The study was conducted from July to September 2012 by means of measurements taken during the smelting process, with 45 minutes set for a one-time smelting work cycle when it comes to personal air sample and area air sample. As such, daily work hours were classified into 360 minutes for measurement. The analysis of lead concentration was conducted using AAs based on the NIOSH 7300 method. Results: In the case of the personal specimens that were subjected to periodical measurement 45 minutes per one session during the smelting process, 40 out of 42 specimens measured were found to contain lead, with an average concentration level of $0.028mg/m^3$ (Max: $0.182mg/m^3$, Min: $0.005mg/m^3$, TWA-more than 50%: 4 out of 6 units). In the case of regional specimens, lead was detected in 45 out of 48 specimens measured, with an average concentration level of $0.037mg/m^3$ (Max: $0.220mg/m^3$, Min: $0.007mg/m^3$ ). In the case of regional specimens subjected to measurement using a day as the work cycle, lead was detected in 15 out of 15 specimens measured, with an average concentration level of $0.049mg/m^3$ (Max: $0.478mg/m^3$, Min: $0.005mg/m^3$ ). Conclusions: It concluded that smelting process workers in steelmaking are exposed to lead because scrap iron is used as a raw material. It is thus necessary to introduce legal management to prevent occupation-related disease in smelting process workers in steelmaking.

• Journal of Environmental Health Sciences
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• v.33 no.6
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• pp.506-512
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• 2007

This study was conducted to describe the exposure levels of welding fumes by the type of manufacturers, work process, welding type and the size of manufacturers, and to find out the trend of chronological changes of airborne welding fume levels. The subjects of this study were 509 manufacturers, consisting of 11 types of manufacturers, 3 work processes, 7 welding types, in Busan from January, 1997 to December, 2005. Airborne concentration of welding fume was determined by manual of National Institute for Occupational Safety and Health (NIOSH), and the data were analyzed by using SPSS 10.0 for Windows program. The mean concentration of airborne welding fume in all manufacturers was $1.29\;mg/m^3$ (Range: $0.01{\sim}3.00\;mg/m^3)$. The level of welding fume was the highest, as $1.96\;mg/m^3$, for manufactures of motor vehicles, trailers and semi-trailers, which was lower than $5.0\;mg/m^3$ of 8 hr-TWA in Korean permissible exposure limit for welding fume. There was a significant difference in the mean levels of welding fumes by work process, showing the highest in welding workshop ($1.39\;mg/m^3$), followed by pipeline welding workshop ($1.26\;mg/m^3$) and engineering workshop ($1.20\;mg/m^3$). Among welding types, the mean level of welding fume was the highest in the type of $CO_2$ & arc welding, as $1.46\;mg/m^3$, followed by $CO_2$ welding ($1.40\;mg/m^3$), shielded metal arc welding ($1.31\;mg/m^3$), spot welding ($1.27\;mg/m^3$), and so on. The highest mean level of welding fume was $1.58\;mg/m^3$ in work process of pipe line welding workshop for the manufacturers of basic iron and steel, and $2.27\;mg/m^3$ in the type of arc welding for the manufactures building ship and boats. By the size of manufacturers, the mean concentration of welding fume for manufactures in small scale with less than 50 workers was the highest as $1.45\;mg/m^3$ (Range: $0.07{\sim}3.00\;mg/m^3)$. The mean level of welding fume was the highest as $1.39\;mg/m^3$ both in 1997 and in 2005, showing a trend of fluctuating periodically within a range of $1.10{\sim}1.39\;mg/m^3$. The above results suggested that more effective control program for work environment producing welding fumes should be developed and applied since there were significant variations in welding fume levels by the type of manufacturers, work processes, welding types, the size of manufactures, and by year.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.321-327
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• 2009

1,3-butadiene is classified as suspected human carcinogen, group A2(American Conference of Governmental Industrial Hygienists, ACGIH). In Korea, 1,3-butadiene has been used as a raw material; monomer, homopolymer, polybutadiene latex, acrylonitrile-butadiene-styrene(ABS) and styrene-butadiene rubber(SBR), in the petrochemistry and precision chemistry industry. As petrochemistry industry in Korea has been developed, the potential exposure possibility of 1,3-butadiene to workers can be increased. Therefore the purpose of this study is to evaluate airborne 1,3-butadiene concentration and workers' exposure levels in the workplace using 1,3-butadiene. Air samples were collected with 4-tert-butyl catechol(TBC) charcoal tube(100 mg/50 mg) and were analyzed by gas chromatograph/flame ionization detector(GC/FID) according to the Choi's method(2002). Geometric mean (GM) and arithmetic mean (AM) of total 59 workers' exposure concentrations to airborne 1.3-butadiene were 0.042 ppm and 1.51 ppm, respectively. Although most samples were lower than 1ppm, 2 samples(21.5ppm and 33.1ppm as 8hr-TWA) were exceeded the Korean standard(2ppm) over 10 times at the repair process in synthetic rubber and resin manufacture industry. 14 samples(41%) of total 34 short-term air samples were exceeded the Korean standard(10ppm as STEL) of Ministry Labor. 1,3-butadiene concentration(GM) in the synthetic rubber and resin manufacture industry(7.87ppm) was significantly higher than that in the monomer manufacure industry (0.35ppm)(p<0.05). Also in the sampling and repair process, each GM(range) was 1.39ppm(N.D.-469.6ppm) and 7.85ppm(N.D.-410.2ppm). In conclusion, it depends on the industry and process, 1,3-butadiene can be exposed to workers as high concentration for short-term.

• International Journal of Safety
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• v.3 no.1
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• pp.27-31
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• 2004

Some of the petroleum products contain benzene which is well known as a confirmed human carcinogen. For example, gasoline products contain benzene ranging up to several percents by weight. High exposures to the benzene and other organic solvents would be likely to occur during intermittent tasks and or processes rather than continuous jobs such as sampling, repair, inspection, and loading/unloading jobs. The work time for these jobs is various. However, most of work time is very short and the representative time interval is 15 minutes. Thus, it is preferable to do exposure assessment for 15 minute time weighted average which is known as a short time exposure level(STEL) by ACGIH rather than for 8-hours TWA. It is particularly significant to the exposure monitoring for benzene since it has been known that the exposure rate plays an important role to provoke the leukemia. Due to the large variations, a number of processes/tasks, the traditional sampling technique for organic solvents with the use of the charcoal and sampling pumps is not appropriate. Limited number of samples can be obtained due to the shortage of sampling pumps. Passive samplers can eliminate these limitations. However, low sampling rates resulted in collection of small amount of the target analysts in the passive samplers. This is originated the nature of passive samplers. Field applications were made with use of passive samplers to compare with the charcoal tube methods for 15 minutes. Gasoline loading processes to the tank lorry trucks at the loading stations in the petroleum products storage area. Good agreements between the results of passive samplers and those of the charcoal tubes were achieved. However, it was found that special cautions were necessary during the analysis at very low concentration levels.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.3
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• pp.193-201
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• 2006

This study was performed to investigate employee exposures to waste anesthetic gases, such as enflurane and sevoflurane in operating rooms of general surgical, children's and dental clinics of a large hospital located in Seoul and to analyze factors affecting the concentrations of waste anesthetic gases. The results of the study are summarized below. 1. Based on results of personal and area samples for airborne enflurane, all of the employees investigated in this study were exposed to airborne enflurane concentrations below the ACGIH-threshold limit value (TLV) of 75 ppm. 2. However, based on results of personal samples for sevoflurane, employees of two (2) out of eleven (11) operating rooms were exposed to sevoflurane concentrations in excess of the NIOSH recommended exposure limit (REL) of 2 ppm. A similar trend was found in the area samples. 3. To investigate the source of sevoflurane emissions, airborne sevoflurane concentrations were measured on an anesthesia machine, a drug cabinet and a desk. It was indicated that the geometric means were 0.93 ppm, 0.83 ppm and 0.72 ppm, respectively. 4. Factors affecting waste anesthetic gas concentrations were the age of anesthesia machine, the volume of operating room and the extent of ventilation (p<0.05). 5. It is recommended that the use of anesthesia equipments be properly controlled, the operating room be well ventilated, and the airborne concentrations of anesthetic gases be continuously monitored.