• 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.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.2
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• pp.103-107
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• 2013

Objectives: The principal purpose of this study is to statistically compare dust levels among farmers with and without feeding in a nursery pig building. Methods: Total dust and respirable dust were measured by personal sampling method, and TSP and PM10 were monitored by the direct recording method in the pig building. Results: IIn the personal samples, mean exposure levels of total and respirable dust were higher among the farmers who conducted feeding compared to farmers who did not. A significant difference between farmers with feeding and farmers without feeding was found in total dust concentration(p<0.05), whereas there was no significant difference in respirable dust concentrations. In real-time monitoring of dust based on area sampling, the highest levels of total and respirable dust were detected in the feeding time periods; $4.33{\pm}2.57mg/m^3$ for TSP and $2.53{\pm}1.02mg/m^3$ for PM10, respectively. During time periods without feeding, the levels of total and respirable dust ranged from 1 to $2mg/m^3$ and from 0.5 to $1.5mg/m^3$, respectively. Conclusions: In terms of association of feeding work and air sampling location, the mean concentrations of total and respirable dust were highest in area sampling with feeding and lowest in personal sampling without feeding. However, a significant difference among groups investigated according to air sampling condition was found in total dust.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.183-191
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• 2005

This study is designed to compare the performance of established samplers (personal air sampler and MiniVOL portable air sampler) commonly used in the air environment or work environment with that of the sampler made by remodeling the air bubble generator for aquarium fishes. Sampling method used in this study is the filter collection method for PM10 and total suspended particles (TSP), the liquid collection method for sulfur dioxide ($SO_2$) and nitrogen dioxide ($NO_2$), and the solid collection method for toluene, respectively. There is not a significant difference in the average concentration of TSP between the Gilian personal air sampler (1st, $0.316{\pm}0.095$; 2nd $0.191{\pm}0.090$; 3rd, $0.185{\pm}0.073mg/m^3$) and the remodeled sampler (1st, $0.317{\pm}0.106$, 2nd $0.201{\pm}0.050$; 3rd $0.189{\pm}0.081mg/m^3$). There are also not significant differences in the average concentration of PM10 among the Gilian personal air sampler ($0.058{\pm}0.006mg/m^3$), the remodeled sampler ($0.052{\pm}0.008mg/m^3$) and the MiniVOL portable air sampler ($0.054{\pm}0.007mg/m^3$). The average concentration of the SO2 by the established sampler and the remodeled one is $3.79{\pm}0.21ppb$ and $3.45{\pm}0.15ppb$, respectively. In addition, there are not sigmficant differences in the average concentration of the NO2 between the Gilian personal air sampler (1st, $0.325{\pm}0.068$; 2nd $0.341{\pm}0.206$; 3rd, $2.971{\pm}0.078{\mu}g/m^3$) and the remodeled sampler (1st, $0.300{\pm}0.062$; 2nd $0.332{\pm}0.144$, 3rd, $2.968{\pm}0.085{\mu}g/m^3$). There are not significant differences in the average concentration of toluene between the Gilian personal air sampler (1st, $0.499{\pm}0.072$; 2nd $0.598{\pm}0.112$; 3rd $2.284{\pm}0.077{\mu}g/m^3$) and the remodeled sampler (1st, $0.463{\pm}0.133$; 2nd $0.603{\pm}0.082$; 3rd $2.353{\pm}0.115{\mu}g/m^3$). From these results, we can conclude that the performance of the remodeled sampler is not different from that of established samplers. There is possibility that the remodeled sampler can be used as a alternative device for Gilian personal air sampler in area and personal air sampling.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.217-223
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• 2012

Objectives: This study was conducted to evaluate personal and area exposure of airborne nicotine during harvest and weaving tasks in tobacco farms. Methods: Nicotine was measured with NIOSH method 2551 and Passive sampler which was validated in previous papers for area and personal sampling. Results: The average (geometric mean) concentrations of nicotine with two different tasks in personal sample were 6.5 ${\mu}g/m^3$ (harvest), 32.6 ${\mu}g/m^3$ (weaving) and in area sample were 0.8 ${\mu}g/m^3$ (harvest), 57.2 ${\mu}g/m^3$ (weaving). There was significant difference in area sample between harvest and weaving task (p=0.000). Also, there was significant difference with personal sample (p=0.000). Conclusions: It was found that weaving task should be considered to be the first priority for reducing nicotine exposure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10C
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• pp.965-975
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• 2005

In this paper, we propose and evaluate joint carrier and sampling frequency offset estimation schemes based on the channel estimation sequences in PLCP (Physical Layer Convergence Procedure) preamble for the proper and effcient synchronization of the MB-OFDM WB (Multi-Band Orthogonal Frequency Division Multiplexing Ultra Wide Band) systems which have recently drawn explosive attention for future W-PAN (Wireless Personal Area Network) applications. In the joint estimation schemes, we first estimate the sampling frequency offset, and then estimate the carrier frequency offset using the estimated sampling frequency offset. Moreover, to improve the reliability of the estimated offset values, each process uses a combination scheme based on weighting factors. Simulation results using IEEE 802.15 Task Group 3a UWB channel models reveal that the estimation scheme using the simple weighting factors based on easily-measurable received signal power of each sub-channel shows favorably comparable performance to the ideal scheme using the weighting factors based on the perfectly-estimated frequency response of the channel.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.854-860
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• 2014

Workers engaged in car inspection works have been exposed to many occupational hazards including noise, particulate matter, and volatile organic substances. Noise-induced hearing loss(NIHL) is one of the leading health hazards among Korean workers. The aim of this study is to evaluate the noise levels in several car inspection shops by introducing the evaluation methods of KMOEL/OSHA and ACGIH. Six sites in central area of Korea were selected to monitor the noise levels of workers by personal and area sampling methods for two consecutive days in spring, summer, fall and winter seasons. Dosimeters have been used for this noise monitoring program. Obtained noise levels by the evaluation method according to KMOEL/OSHA are the range of 50.2~88.2 dB(A), these are lower than KOEL/OSHA standards level of 90 dB(A). But highest noise by ACGIH's evaluation methodology is recorded 92.3 dB(A) and is greater than NIHL standard level of 85 dB(A). So that many workers may be exposed to the dangerous noise environment. The higher the car inspection loads daily, the higher the noise levels in the sites. Seasonal fluctuation of noise levels at the process might give monitoring results with high variations. Area noise levels showed higher than those of personal sampling, which illustrate some high noise spots in the car inspection areas.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.1
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• pp.11-24
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• 2011

Working in a research laboratory means exposure to a wide range of hazardous substances. Several studies indicated that laboratory workers, especially working with chemicals, might have an increased risk of certain cancers. However, exposure assessment data in laboratory settings are scarce. This study was performed to examine several approaches for quantitatively assessing the exposure levels to volatile organic compounds (VOCs) among workers in chemistry laboratories. The list of 10 target VOCs, including ethanol, acetone, 2-propanol, dichlormethane, tetrahydrofuran, benzene, toluene, n-hexane, ethyl acetate, chloroform, was determined through self-administered questionnaire for six chemistry research laboratories in a university, a government-funded research institute, or private labs. From September to December 2008, 84 air samples were collected (15 area samples, 27 personal time weighted samples, 42 personal task-basis short-term samples). Real time monitors with photo ionization detector were placed during the sampling periods. In this study, benzene was observed exceeding the action levels, although all the results were below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV). From the air sampling results, we concluded that (1) chemicals emitted during experiments could directly affect to neighbor office areas (2) chemical exposures in research laboratories showed a wide range of concentrations depending on research activities (3) area samples tended to underestimate the exposures relative to personal samples. Still, further investigation, is necessary for developing exposure assessment strategies specific to laboratories with unique exposure profiles.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.910
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• pp.1243-1252
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• 2004

The purpose of this study was to identify the impact of personal values on fashion orientation. As personal values, this study adopted materialism and consumer conformity. Data were gathered by surveying university students living in Seoul metropolitan area using convenient sampling, and 325 questionnaires were used in the statistical analysis. In analyzing data, confirmatory factor analysis and path analysis were conducted using structural equation modeling. Confirmatory factor analysis revealed that fashion orientation has three factors such as fashion leadership, fashion interest, and importance of being well dressed. Path analysis showed that centrality factor of materialism spurred all three factors of fashion orientation and that happiness factor of materialism gave rise to importance of being well dressed of fashion orientation. Informational conformity also significantly increased all three factors of fashion orientation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.1
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• pp.50-66
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• 1998

This study was conducted to estimate crystalline silica contents in airborne respirable dust from various manufacturing industries and to compare analytical performance of two methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy (FTIR). For this study, various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: foundry, brick, potteries, concrete, and abrasive material, etc. Both personal and area respirable dust samples were collected using 10 mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size, polyvinylchloride (PVC) filters as collection media. In addition, total dust samples were collected side-by-side to the respirable samples. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 0500, 7500, and 7602 for dust collection and quartz analysis. In addition, bulk samples were collected and analyzed by X-ray fluorescence (XRF) for minerals. In this article, only the results obtained from foundry are reported. The results from various other industries will be published in future articles. The respirable dust concentrations from personal samples by cyclone were $0.46-1.06mg/m^3$ and those from area samples were $0.34-0.73mg/m^3$. Dust concentrations of personal samples were significantly higher than those of area samples. The highest dust concentration was obtained from the personal samples of the finishing operation. Total dust concentration ranged $1.24-3.40mg/m^3$. The mean quartz contents estimated by FTIR and XRD in the personal respirable dust samples were 5.12% and 4.41%, respectively, without significant difference between them. For quartz analyses, the two techniques were highly correlated with $r^2$ ranged 0.803-0.920. But the results by FTIR were mostly higher than those by XRD. In addition, cristobalite was not detected by FTIR. Significant correlations between contents of crystalline silica and such minerals as $Al_2O_3$, CaO, $TiO_2$, and $K_2O$ suggest possible interferences from these minerals.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.157-166
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• 2021

This study aims to investigate the impact of green corporate identity and employees' green identification on green business performance of international automobile manufacturers in Thailand. It involves 400 employees from the target study area, using questionnaires to collect data from January to February 2021, with purposive and convenient sampling methods. Data analysis employed structural equation modeling (SEM). The results show that green corporate identity has a significant impact on employees' green personal-social identification and green business performance; meanwhile, employees' green social identification has a significant impact on green business performance. However, employees' green personal identification has a significant impact on green business performance only through employees' green social identification. Green corporate identity can increase the corporate' green business performance via economic, environmental and social aspects through employees' green personal-social identification. The findings suggest that green corporate communication through visual identity, employee behaviors, culture, policy products and services in response to environmental forces and drivers to create the green corporate identity is deemed to systematically work. Furthermore, the findings also suggest that employees' green identification on both personal and social levels can be a significant issue that the managers in automobile manufacturers should pay attention as well.