• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.34 no.3
• /
• pp.189-192
• /
• 2024

Objectives: To protect researchers using chemicals, it is necessary to monitor whether the working environment is well managed through the performance evaluation of the local exhaust system in the research laboratory. These results need to be reflected in the work environment management policy of research laboratories in the future. Methods: By measuring the capture velocities of fume hoods and arm hoods, which are the most commonly used local exhaust systems in research laboratories in a domestic research institute, we tried to confirm the degree to which the actual capture velocity values and legal standards were satisfied. The capture velocities were measured using a hot wire wind speedometer (TSI 9565-P, USA, 2016 with all exhaust systems in operation in the laboratory. As for the measurement position for each local exhaust system, in the case of the fume hood, the wind speed in the center of the opening surface was measured after opening 50% of the door of the hood. For the arm hood the capture velocities were measured at a distance of 10 cm vertically from the opening surface of the hood Conclusions: The total number of arm hoods measured was 546, and the average capture velocity was 0.61 m/sec with an S.D of 0.49. Among them, 99 satisfied the capture velocity standard of 1m/sec, meaning only 18.1% of the total satisfied with the standard. The total number of fume hoods measured was 625, and the average control wind speed was 0.48 m/sec with an S.D. of 0.17. Among them, the number of fume hoods that satisfied the capture velocity standard of 0.4 m/sec was 518, meaning 82.9% of the total satisfied the standard. Therefore, research institutes that operate local exhaust systems to protect researchers from chemicals should further strengthen the capture velocity management of hoods, and government agencies need to reflect this in work environment management policies based on further evaluation results.

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

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.32 no.4
• /
• pp.340-349
• /
• 2022

Objectives: The importance of MSDS is emphasized for communicating hazardous information due to the increase in the types and usage of chemical substances. The purpose of this study is to assess the reliability of MSDS by collecting and examining paint thinners commercially available in South Korea. Methods: Twenty-five paint thinners were purchased at paint stores and the provision of MSDS was checked. Quantitative and qualitative analysis was performed on the chemical constituents of the thinners using GC-MSD and GC-FID. Reliability was evaluated by the MSDS collection rate for the paint thinners and calculating the rate of matching between laboratory analysis results and the contents and composition of chemical constituents given in the MSDS. Results: Unlike a study conducted in 2006, MSDS were provided for all 25 thinners. As a result of qualitative analysis using GC-MSD, 104 chemical substances were detected. The substances with the highest detection rate were identified in the order of toluene, butyl acetate, acetone, xylene, and ethyl benzene. A component matching rate of 41% was found by comparing the differences between the number of substances detected in laboratory testing and the number of substances listed in the MSDS. Benzene, a carcinogen not listed in the MSDS, was detected in two thinners produced by a small company. The detected benzene contents were 0.039 and 0.040%. When benzene is used, it should be strictly handled according to the Industrial Safety and Health Act. However, since it is not listed on the MSDS, it is judged that benzene was not being managed as a carcinogen in the workplaces where it is used. Conclusions: Since the reliability of MSDS, which play an important role in hazard communication, was evaluated to be low, it is necessary to systematically and continuously secure this reliability. In particular, carcinogens should be managed more strictly.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.11 no.1
• /
• pp.48-55
• /
• 2001

The purpose of this study was to evaluate the analytical accuracy and precision of microwave oven digestion/atomi absorption spectrophotometry (AAS) for analyzing airborne chromium collected on mixed cellulose ester membrane (M filter from the work environment, and to compare the accuracy and the precision with those of the National Institute for Occupational Safety and Health (NIOSH) Method #7024 hot plate digestion/AAS method. For this study, field air sample pairs were collected from a electroplating process, and spiked samples in a laboratory were prepared and using these samples. Two digestion methods were comp; and evaluated in terms of recovery rate and bias as indices of accuracy and coefficient of variation as a index of precision. The results and conclusions are as follows. In spiked samples, the accuracies (% mean recoveries) of hot plate/AAS and microwave oven/AAS method were 97.19%, 97.1%, respectively, and the precisions (pooled respectively, and the precisions (pooled coefficient of variance, $CV_{pooled}$) 6.93% and 3.88%, respectively. The biases of hot plate ani microwave oven methods were 4.56 - 14.7% and 2.22 - 7.42% respectively. There was no statistically significant difference between hot plate and microwave oven methods recovery rates of spiked samples (p>0,05). Also, no statistically significant difference was shown among the concentrations of air samples determined by two method (p>0.05). In conclusion, microwave oven/AAS method h excellent accuracy and precision, and advantages such as time-saving and simple procedure in comparison with the classical NIOSH method. Therefore, this method can be use widely to analyze airborne chromium collected on MCE filter from the work environments.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.20 no.1
• /
• pp.41-46
• /
• 2010

The purpose of this study is to assess the level of fungi concentration in the university laboratories in Seoul, Korea, and to investigate factors contributing to these concentrations. The samples were taken from three spots in each laboratory; the top of sink, the center of laboratory, and the front of ventilation system, i.e fume hood at the chemical laboratory and clean bench/biosafety cabinet at the microbial laboratory. Air samples were collected using the single-stage Anderson sampler (Quick Take 30) at a flow rate of 28.3 l/min for 5 min on nutrient media in Petri-dishes located on the impactor. Fifty-two air samples were collected from 19 different laboratories (13 microbiology laboratories, 6 chemistry laboratories) in the university, and concentrations of airborne fungi showed no significant difference (p>0.05) between microbiology and chemistry laboratory, and also no significant difference at three locations (sink, center, front of ventilation system) in microbiology and chemistry laboratories. Average concentrations of fungi in 19 laboratories ranged from 7 to 459 cfu/$m^3$, with an overall Geometric Mean of 52 cfu/$m^3$. Airborne fungi concentrations of 6 samples (12 %) exceeded 150 cfu/$m^3$, the guideline of WHO. The ratios of Indoor/Outdoor for airborne fungi ranged from 0.2 to 4.8 (mean = 1.6). Related factors were measured such as relative humidity, temperature, and laboratory area. Temperature and laboratory area showed no significant relations to concentrations of airborne fungi except for relative humidity in the laboratory Concentrations of fungi were significant different (p<0.01) between rainy or cloudy and sunny. However, there was no significant difference between general ventilation and nongeneral ventilation.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.26 no.2
• /
• pp.139-146
• /
• 2016

Objectives: This study aimed to confirm the optimal processing conditions of the asbestos stabilizer by considering various actual environments at the time of stabilization treatment of the ceiling materials containing asbestos with asbestos stabilizer. Methods: The anti-scattering performances of the asbestos stabilizer were confirmed by considering the method and quantity of the asbestos stabilizer treated, comparing the loss weight by measuring the weight of ceiling materials prior to and after having treated 30, 50, 100, 200, and 400 of stabilizer using the brush and spray. The effects of backside dust and steel frame structure on the performances of the stabilizer was also confirmed by comparing samples with and without the dust on the rear surface removed by wiping the ceiling material specimens and the blinding treatment simulated by using tape. Results: The asbestos stabilization treatment using the brush method in comparison with the use of a spray has reduced stabilizer loss, resulting in better anti-scattering performance. In addition, the stabilizer loss is increased with increasing treatment quantity; as a result, treating a larger quantity of stabilizer does not improve the performance. For the conditions related to ceiling materials, the anti-scattering performance is enhanced by removing the backside dust and spreading the stabilizer evenly on the masking portion by steel frame structures. Conclusions: Based on these results, it is determined that the appropriate choice of the tool used for the treatment of the asbestos stabilizer and the appropriate quantity of asbestos stabilizer were needed at the time of actual stabilization processing of the ceiling materials containing asbestos. Moreover, this study confirmed that preliminary processing and verification of the structure at which the ceiling materials are installed can enhance the effectiveness of prevention of the scattering of asbestos into the air.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.4 no.2
• /
• pp.180-188
• /
• 1994

This study was designed to investigate qualitatively whether respirators now being used in workplaces tit workers iflfaces well or not. Leak sites were determined after exposing the subjects to fluorescent aerosol and were analyzed by gender, brand and manufacturing nation. The results were as follows ; 1. Among those leak sites which were classified into four areas(nose, cheek, lip and chin), test aerosol was mostly deposited on the nose and the cheek areas. 2. The mean number of leak sites observed from the female subjects were 2.3 while the number were 2.2 from the male subjects. The most frequently observed leak site was nose and followed by chin, lip and cheek in descending order of frequency. 3. Among different brands of respirators, different leak sites were observed. Test subjects wearing the Sand N brands were more heavily exposed than those of wearing the D and M brands. 4. No significant difference of the number of leak sites were found between Korean-made and American-made masks. However, the most frequent leak site observed for the Korean-made ones was the nose area while it was the chin area for the American-made ones. 5. Analyses of 97 leak sites by shape showed that 27(27.8%) were point types, 54(55.7%) diffuse types and 16(16.5%) streamline types. 6. Test subjects indicated that the facepieces of Korean-made respirators were harder and smaller in size than those of American-made one. The most comfortable respirator selected was the respirator by the N Co. and the most uncomfortable one was the respirator by the D Co. This study suggests that many half-mask respirators now being used in the workplaces may not fit to workers well. Therefore, when selecting respirators, employers are advised to test respirators if they fit to workers well. And manufacturers are recommended to produce effective and comfortable respirators tested qualitatively and quantitatively not only in the laboratory but also in the field.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.34 no.2
• /
• pp.156-165
• /
• 2024

Objectives: This study aims to identify and analyze the exposure status of welding students in specialized high school welding labratories, compare it with the exposure to welding hazards of industrial workers, and seek to improve the educational environment for youth through domestic and international exposure standards. Methods: This study compares the level of exposure to hazardous factors in a welding laboratory of a vocational high school in Jeollanam-do and a welding process in a general industrial site by measuring the work environment. A 10-question survey was conducted to review the effects of welding hazards on the human body, carcinogenicity information, international (US, UK, France) exposure standards, general characteristics between the two groups, and awareness of occupational health. Results: Exposure to hazardous factors in both groups was below the standards set by MOEL. Specialized high school students were exposed to higher levels than workers, and some hazardous factors exceeded the standards when compared to international exposure standards. During the survey, students were less aware of the hazards of welding, safety and health education, and the need for work environment measurement than workers. Conclusions: For the respiratory protection of students in vocational high school welding labs, it is necessary to create a comfortable training environment. Exposure standards for harmful factors should be strictly applied, such as overseas standards, or exposure should be limited by setting a limit on the number of hours of welding practice per week. In addition, it is necessary to conduct safety and health education for welding students to raise their awareness of the importance of measuring the working environment and wearing appropriate protective equipment.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.20 no.4
• /
• pp.236-240
• /
• 2010

This study demonstrates the use of a chemical containing potassium superoxide (KO2) to convert carbon dioxide (CO$_2$) in air to oxygen (O$_2$). A oxygen generating closed-circuit SCBA (self contained breathing apparatus) removes carbon dioxide by a chemical reaction with potassium dioxide that consumes the carbon dioxide and produces oxygen. Considering the disasters, there is a need to develop strategies to enable the introduction of self-contained self rescuers (SCSR). The potassium superoxide reacts with the wears breath to produce oxygen and absorb carbon dioxide. If the respiration rate of a person is 5 MET (metabolic equivalent), to say 30 L/min, at disaster such as fire, mass of potassium superoxide was evaluated as 33.3 g with yield and safety factor. Four researchers tested on a laboratory treadmill breathing through SCSRs in a closed circuit, it appears useable for 9 minutes.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.16 no.2
• /
• pp.91-100
• /
• 2006

The purpose of this study was to validate alternative method by using non-carcinogenic, and less toxic solvents than NIOSH analytical method 5524 for measuring the airborne MWFs in workplaces. In laboratory tests, the ETM solvents(mixture of same volume for ethyl ether, toluene, and ethanol) were selected. The alternative method of analyzing MWFs, referred to as the ETM solvent extraction method, showed 0.04 mg/sample as LOD, and 0.15 mg/sample as LOQ. The analytical precision (pooled CV, coefficient of variation) of the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was 1.5%, 2.0%, 2.6%, 1.6%, respectively, which was similar to the precision (2.6%) of NIOSH analytical method (NIOSH 0500) for total dust. The analytical accuracy by recovery test, spiked mass calculated as extractable mass, was almost 100%. As the result of storage stability test, metalworking fluid samples should be stored in refrigerated condition, and be analyzed in two weeks after sampling. The 95% confidence limit of the estimated total standard error for the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was ${\pm}12.6%$, ${\pm}12.5%$, ${\pm}14.0%$, and ${\pm}13.6%$, respectively, which satisfied the OSHA sampling and analytical criteria.