• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.2
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• pp.198-209
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• 2016

Objectives: This study aimed to provide basic data for the improvement of the guidance services for the management of the workplace environment of the specialized health management institution, by making inquiries on the perception and extent of practice by health managers and workers in the workplace. Methods: Workplaces with officially noted environmental hazards of noise, organic compounds and/or dust-metals were selected in a South Korean metropolitan city in 2015. The workplace health managers(hereinafter referred to as 'manager') and workers at 97 workplace were interviewed. Managers are those who are in charge of health management at the corresponding workplace and the workers were subjected to in-depth interviews by sampling one worker for each of the workplace. Results: The majority of the managers acknowledged the guidance services of the specialized health management institution affirmatively. Regarding the extent of practice in accordance with the guidance on engineering improvement, only 23 managers(37.1%) responded. With respect to education, 40 managers(41.2%) responded that it was implemented along with 35 workers(36.1%) who responded that they received education, showing no significant difference between manager and worker. Regarding the actual wearing of the protective equipment, however, 83 of the manager(85.6%) insisted that workers wore the protective devices while only 44 workers(49.5%) responded that they actually wore the devices, thereby illustrating a significant difference between managers and workers. Conclusions: These results suggest the urgent necessity of improvement in the mechanism of guidance services of the specialized health management institution for the workplace environment management.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.2
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• pp.94-101
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• 2010

This study was performed to examine the asymmetry of hearing loss among the noise exposed male workers. Findings of otoscopic examination, pure tone audiometry and tympanometry were evaluated for 179 male workers working in the noise exposed workplace. And also selfadministered structured questionnaires were used for each worker's work-related and general characteristics including personal health behaviors. There were significant differences of hearing threshold between right and left ears at 1,000 Hz and 3,000 Hz(p<0.05). And also significant differences of hearing threshold were noted in the age group over 50 at 3,000 Hz, the high risk drinking group either at 3,000 Hz and 4,000 Hz, the work duration group 10-19 years at 3,000 Hz, the noise exposure group under 90 dB(A) at 3,000 Hz, the noise exposure group over 90 dB(A) at 1,000 Hz, the non-wearing protective device group at 4,000 Hz, and the wearing protective device group at 3,000 Hz(p<0.05). Further study is needed to explore the extent and the related factors of the asymmetry of hearing loss in the general population and occupationally noise exposed group.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.65
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• pp.65-73
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• 2001

In this study, psychophysiological stress was quantitatively evaluated at various car interior noise levels by using Electroencephalogram(EEG). An experiment was performed to investigate the most comfortable range of noise level during simulated driving condition. Twelve healthy volunteers participated in the experiment. They were asked to operate the driving simulator while six levels of interior noise were given, such as 45dB(A), 50dB(A), 55dB(A), 60dB(A), 70dB(A), 80dB(A), and maximal subjective noise level. EEG signals were recorded for 60 seconds in each noise level. The power spectral analysis was performed to analyze EEG signal. At the same time, psychological stress was also measured subjectively by using a magnitude estimation method. The results showed that subjective stress and EEG spectrum indicated a statistically significant difference between noise levels. In particular, high level noise produced an increase in beta power at temporal(T3, T4) areas. It was also found that beta activity was highly correlated with subjective perception of discomfort, and subjects responded to car interior noise as arousing or negative stimuli. Moreover, beta power remained stable above 70dB(A), whereas subjective discomfort continued to increase even above 70dB(A) We concluded that brain waves could provide psychophysiological information of drivers emotional reaction to car interior noise. Thus, EEG parameters could be a new measure to determine optimal noise level in ergonomic workplace design after further verification in various experimental conditions.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.748-755
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• 2011

After the Industrialization of 1960s, while it has greatly contributed to the industrial development owing to acceleration of mechanization, but it is real situation that the countermeasure to noise damage generating at the loud noise workshop is scarcely made. Especially, the machine noise made at factory and workplace is so shocking and repeatedly reiterating terrible noise that most of the spot workers are forcedly imposing such dangers as the severe unpleasant feeling and hearing impairments. On such point of view, this research has attempted to extract the proper rating vocabulary in order for evaluation on machine noise made at the high noisy workshop, therefore it is considering that those extracted vocabularies could be utilized as the useful psycho-acoustic experiment for evaluation on machine noise, also for establishment of regulation standard in domestic high noisy workshop.

• Safety and Health at Work
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• v.12 no.2
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• pp.184-191
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• 2021

Background: Hearing protection devices (HPDs) are often used in the workplace to prevent hearing damage caused by noise. However, a factor that can lead to hearing loss in the workplace is improper HPD fitting, and the previous literature has shown that instructing workers on how to properly insert their HPDs can make a significant difference in the degree of attenuation. Methods: Two studies were completed on a total of 33 Hydro One workers. A FitCheck Solo field attenuation estimation system was used to measure the personal attenuation rating (PAR) before and after providing one-on-one fitting instructions. In addition, external ear canal diameters were measured, and a questionnaire with items related to frequency of use, confidence, and discomfort was administered. Results: Training led to an improvement in HPD attenuation, particularly for participants with poorer PARs before training. The questionnaire results indicated that much HPD discomfort is caused by heat, humidity, and communication difficulties. External ear canal asymmetry did not appear to significantly influence the measured PAR. Conclusion: In accordance with the previous literature, our studies suggest that one-on-one instruction is an effective training method for HPD use. Addressing discomfort issues from heat, humidity, and communication issues could help to improve the use of HPDs in the workplace. Further research into the effects of canal asymmetry on the PAR is needed.

• Journal of the Korean Society of Safety
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• v.11 no.4
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• pp.135-142
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• 1996

Prolonged in-plant personnel exposure to high noise levels results in permant hearing damage. There are no way to correct this hearing damage by treatment or use of hearing aids. Therefore, every employer is responsible for providing a workplace free of such hazards as excessive noise. This study was carried out to evalute and predict a given noise environment based on specific limit as the noise guarantee for a newly-founded petrochemical plant. The maximum total sound level should not exceed 85dBA in the work area, except where the area is defined as a restricted area and 70dBA at the plant boundary. Prediction of the noise levels within the plant area for a newly-founded petrochemical plant was achieved by dividing all plant area into 20m$\times$20m regular grid spaces and noise level inside the area or unit that in-plant personel exposure to high noise levels was estimated computed into 5m$\times$5m regular grid spaces. The noise level at the grid point that was propagated from each of the noise sources(equipments) computed using the methematical formula was defined as follows : $SPL_2$=$SPL_1-20log{\frac{r_2}{r_1}}$(dB) where $SPL_1$ =sound pressure level at distance $r_1$ from the source $SPL_2$=sound pressure level at distance $r_2$ from the source As a result, the equipments exceeded noise limit or irritaring noise levels were identified on the specific grid coordinates. As for equipments in the area that show high noise levels, appropriate counter-measures for noise control (by barriers, enclosure, silencers, or the change of equipments, for example) should be reviewed. Methods for identifying sources of noise applied in this study should be the model for prediction of the noise levels for any newly-founded plant.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.163-170
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• 2018

This study was conducted to investigate the effects of noise from dental clinics on workers and to establish a reduction plan. The noise generated by the treatment instrument(Ultrasonic scaler, Hand piece, 3-way syringe, Suction, Compressor) was measured in order to determine the characteristics(level, frequency) of the noise during medical treatment(Oral prophylaxis, Conservation treatment, Prosthesis treatment, Implant Scaling, Tooth eliminating). We also assessed the noise levels in dental clinic using evaluation indicators such as NR-curves and NRN. The results of the analysis showed that the noise generated during the treatment was 85dB(A) ~ 70dB(A) and that the high frequency component was dominant, which would affect the workers working at the dental clinic. The NR-curve analysis showed NR-67 to NR-83 and the high frequency components of 4kHz to 8kHz were predominant and far exceeded noise levels in the workplace. To minimize the noise damage of workers and to provide high quality medical service, it is necessary to establish countermeasures such as wearing a soundproof and periodic hearing tests.

• Journal of the Korea Society of Computer and Information
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• v.27 no.5
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• pp.181-188
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• 2022

In this paper, we proposed of the results of the noise level and appropriate conversation distance by applying the noise characteristics generated during treatment at a dental clinic to the NR-curve and PSIL. As a result of analyzing the noise characteristics during treatment at a dental clinic, it was analyzed that the noise level exceeded 60dB(A), which is the health preservation limit value caused by noise, and the noise level increased as the frequency increased. the result of evaluation applying it to the NR curve, some treatment exceeded the workplace noise standard, and as a result of analyzing the level of conversational disturbance between the worker and the patient, it is desirable to have the conversation at a distance of less than 1M for accurate communication. In order to improve the quality of medical service in dental clinic and to reduce dental fear, it is judged that soundproofing protective equipment is provided to workers, and soundproofing measures are needed for noise sources (treatment devices used in treatment) and sound sources (patients and workers).

• Journal of dental hygiene science
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• v.15 no.5
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• pp.603-611
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• 2015

This research is aimed at cutting off hearing loss and other harmful factors due to noise and providing basic material for noise reduction plan. As the research method, this research assessed noise by measuring acoustic pressure level and frequency in various situation of non-treatment and treatment. As the measurement result, average noise degree of high speed handpiece of non-treatment, ultrasonic waves scaler, and low speed handpiece showed 58~66 dB(A). Average noise degree of scaling of treatment, tooth elimination, and denture adjust showed 73~81 dB(A). The result is inferior to recognized standards of noise induced hearing loss. But the result of assessing this with (noise rating) NR curve was NR-73~78, which exceeded general workplace noise standard. This level can cause hearing loss when exposed to a long time. Therefore, treatment office noise during dental treatment can cause psychological and physical damage in dental clinic employees, and it is urgently required to establish systematic and active noise reduction plan.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.3
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• pp.235-247
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• 1999

This study was performed to investigate what was the most serious occupational factors in small scale industries. Twenty-three occupatonally hazardous substances were measured at the five workplaces in the Eastern Seoul during 1995∼1996. Total of 2,020 samples were analyzed by either GC/FID for organic vapors or AAS for heavy metals. From the results of this study noise was the most serious factor at the selected workplaces. Noise level in the metal processing, the printing, and the auto repairing industries exceeded the 8 hr PEL by 19.7%, 13.6%, and 11.6%, respectively. Mean concentrations of toluene in the shoe making and the printing industries exceeded the assessment crieterion by 6.0% and 3.8%, respectively. Further study of risk assessment of occupational exposure may be required to protect workers from hazardous working conditons.