• 한국산업보건학회지
• /
• 제21권3호
• /
• pp.162-167
• /
• 2011

To identify the relationship between types of job classification (typical and atypical) and the levels of recognition of noise and the hearing threshold shift, a total of 457 workers in a cosmetic company were studied utilizing a questionnaire and the audiometric hearing test. The results were analyzed by factor analysis, t-test, and general linear model, as appropriate. The results showed that atypical workers had higher level of noise recognition but had lower levels of hearing ability, noise exposure, and the knowledge on hearing loss prevention, compared with those of typical workers. The high noise level group of typical workers showed higher threshold shift levels than that of atypical workers. Significant differences were found at 4 kHz for both ears and in right ear only for hearing threshold shift after adjusting age.

• Journal of Preventive Medicine and Public Health
• /
• 제17권1호
• /
• pp.57-63
• /
• 1984

소음작업(騷音作業) 근로자(勤勞者)들의 이보호구장용(耳保護具裝用)의 여부(與否)에 따른 청력보존(聽力保存)의 효과(效果)를 관찰하기 위해 $16{\sim}24$세(歲)사이의 건강(健康)한 여성(女性) 기직공(機織工) 1,237명을 대상(對象)으로 이전(耳栓)을 장용(裝用)하고 있는 자(者)들을 실험군(實驗群), 하지 않고 있는 자(者)들을 대조군(對照群)으로 하고, 1982년(年) 4월에서 1983년(年) 1월(月)사이에 실시된 특수건강진단(特殊健康診斷) 결과지(結果紙)에서 그들의 근속년수(勤續年數), 4,000Hz에서 AA-30A, RION Japon청력계(聽力計)로 측정된 최소가청치(最小可聽値)를 조사 비교하였다. 최소가청치(最小可聽値) 40 dB초과의 경우는 대조군(對照群)의 좌이(左耳) 44.6% 우이(右耳) 40.9%, 실험군(實驗群)의 좌이(左耳) 8.0% 우이(右耳) 6.6%였고 근속년수(勤續年數)가 길수록 대조군(對照群)과 실험군(實驗群) 모두에서 증가(增加)하였다. 최소가청치(最小可聽値)의 분포(分布)는 좌우이(左右耳)사이에 유의한 차(差)를 실험군(實,驗群)과 대조군(對照群) 모두에서 볼 수 없었으나, 대조군(對照群)과 실험군(實驗群)간에는 좌우이(左右耳) 모두에서 통계적으로 유의한 차(差)를 나타내었다(p<0.005). 대조군(對照群)과 실험군(實驗群)사이에 최소가청치(最小可聽値) 40 dB초과에 속하는 경우의 차이(差異)는 근속년수(勤續年數) 1년이하, 3년, 5년, 5년 초과에 따라 각각 좌이(左耳) 26.8%, 38.0%, 43.3%, 45.4%, 우이(右耳) 29.5%, 31.6%, 38.9%, 36.5%로 증가(增加)하는 경향이었다.

• 월간산업보건
• /
• 통권68호
• /
• pp.71-72
• /
• 1993

• 한국의학물리학회지:의학물리
• /
• 제9권4호
• /
• pp.217-225
• /
• 1998

본 연구에서는 A청감보정 소음레벨과 폭로기간에 대한 소음유발 청력손실과 소음폭로 사이의 관계를 해석하였다. 연령과 소음폭로등 다양한 변수에 대하여 청력손실과 청감민감도 변화를 조사하였다. 연구결과 전체 청력손실은 음압의 시간적분에 의한 소음폭로 레벨에 비례하였다. 만약 소음폭로가 노인성 난청보다 크면 연령과 소음에 의해 발생하는 청력손실은 주된 원인이 소음에 의한 것임을 확인하였다. 과도한 소음은 일시적 청력손실의 원인이며, 폭로가 길어지거나 강력하면 영구적 청력손실의 원인이 될 수 있다. 소음유발 청력손실을 겪는 사람의 청력도는 4kHz 영역에서 청감민감도의 급격한 손실을 보여주며, 이 영역은 여러 형태의 산업소음으로 인해 가장 손상받기 쉬운 전형적인 주파수영역임을 확인하였다.

• 한국환경보건학회지
• /
• 제34권2호
• /
• pp.153-160
• /
• 2008

Personal noise exposure was assessed in railroad operators working in 40 operation units including the Gyeongbu line, Honam line, and Janghang line between 2004 and 2006. 8-hour TWA were assessed based on the MOL (Ministry of Labor) guideline on noise evaluation, and 17% of these measurements exceeded 85 dBA while 70% were over 80 dBA. When the ACGIH TLV is adopted, 40% of measurements were over TLV (85 dBA). The noise exposure risk of railroad operators was higher for diesel locomotive operation and longer operational distances; in addition, the risk was higher for passenger car operation compared to freight car driving. Given that in Korea, over the past 30 years diesel locomotives have provided most of the railway's motive power and that hearing protective equipment is not likely to be used by workers during operation, railroad operators are at a high risk of noise-induced hearing loss. The result of audiometric test among 568 railroad operators showed that 32.6% of those tested had a hearing threshold shift of more than 40 dB. In conclusion, this study calls for more fundamental measures including noise control countermeasures within the operation areas, development of equipment that generates less noise and adopting limitation on the operation distance for a work shift.

• Journal of Ginseng Research
• /
• 제34권4호
• /
• pp.336-341
• /
• 2010

One mechanism of inner ear damage by noise-induced hearing loss (NIHL) is the production of reactive oxygen species (ROS). Because Korean red ginseng (KRG) has an anti-ROS effect in various tissues, KRG may have a role in preventing NIHL. A window period exists in which ROS formations continue after noise exposure, and further damage can be prevented by antioxidants. In this study, we aimed to investigate the effects of KRG after exposure to noise. KRG (200 mg/kg) was fed to mice for 3 days after noise exposure. The change in hearing level was analyzed by measuring the auditory brainstem response. To induce a temporary threshold shift (TTS) of hearing, mice were exposed to 110 dB white noise for 3 hours. Fast recovery of hearing was observed in mice fed KRG 1 hour and 1 day after noise exposure for 3 days. The expression of 8-oxoguanine was not observed in the inner ears of mice fed KRG 1 hour after noise exposure, but was evident in the stria vascularis of mice in the control group (noise exposure only). From this study, we conclude that KRG acted as an effective inhibitor of NIHL in TTS cases.

• Safety and Health at Work
• /
• 제11권2호
• /
• pp.199-206
• /
• 2020

Background: In a wide range of industries, noise-induced hearing loss remains one of the most prevalent occupational problems. This study aimed to assess the noise exposure level and associated factors of hearing loss among textile workers in Yangon Region, Myanmar. Methods: A cross-sectional study was conducted at a Textile mill (Thamine), Yangon Region, from April to December 2018. In total, 226 workers who were randomly selected from 3 weaving sections participated in face-to-face interviews using a structured questionnaire. A digital sound level meter and pure-tone audiometer were used for the assessment of noise exposure level and hearing loss, respectively. Logistic regression analysis was performed to assess the associated factors of hearing loss. Results: In total workers, 66.4% were exposed to ≥85 dB(A) of noise exposure, and the prevalence of hearing loss was 25.7%. Age ≥35 years, below high school education, hearing difficulty, tinnitus, hypertension, > 9 years of service duration in a textile mill were positively associated with hearing loss. After adjusting confounding factors, age ≥35 years (adjusted odds ratio = 6.90, 95% confidence interval = 3.45-13.82) and tinnitus (adjusted odds ratio = 2.88, 95% confidence interval = 1.13-7.37) were persistently associated with hearing loss. Conclusion: Providing occupational hazard education and enforcement of occupational safety regulations should be taken to decrease the noise exposure level. The regular audiometry test should be conducted for assessment of hearing threshold shift. The employer needs to implement a hearing conservation program in workplace when noise exposure reaches or exceeds 85 dB(A) for 8 hours.

• 한국산업보건학회지
• /
• 제30권4호
• /
• pp.387-393
• /
• 2020

Objective: This study aimed to investigate the differences in temporary threshold shift (TTS) and recovery patterns according to different types of sound and volume. Methods: TTS and recovery patterns were assessed for eight students after 30-minute exposure to both 70.0 dB and 90.0 dB of factory noise (noise) as well as music. TTS was measured before exposure and two minutes post exposure, and recovery patterns were evaluated every 10 minutes for one hour. The subjects performed activities of daily life and sleeping times as usual but taking drugs or drinking alcohol were prohibited. The experiment was repeated three times with an interval of at least 16 hours. ANOVA and T-test were carried out using SPSS 19.0 for Windows. Results: The hearing threshold of all subjects before exposure was less than 30 dB at all frequencies. Mean TTSs of 70 dB noise and 90 dB noise exposure were 0.14 and 4.48 dB (p<0.001). Meanwhile, the difference in music was insignificant (-0.63 dB and 0.55 dB, p=0.063). A significance in the difference was also found between the mean TTS of music and noise exposure, more obviously at 90.0 dB (p<0.001) than at 70 dB (p=0.232). The TTS differences were found frequency-wise in terms of sound type. Mean TTS by frequency was higher at 4,000 and 6,000 Hz than at other frequencies, and higher in noise than music at the same sound pressure. The TTS difference in each frequency between both sound types was significant at 90 dB (p<0.001). Subjects mostly recovered from TTS in one hour after exposure, but not with 90 dB-noise exposure. Conclusion: TTS and recovery patterns were different depending on the sound type. When exposed to factory noise, TTS was greater and recovery time was longer compared to music at the same sound pressure. These results suggested that the difference in cognitive processes and psychological factors according to the type of sound causes a change in TTS and recovery.

• Journal of Ginseng Research
• /
• 제33권2호
• /
• pp.104-110
• /
• 2009

고려 홍삼이 소음성 난청에서 청력 보호 및 회복에 관여하는 지를 밝히기 위하여 마우스에서 홍삼을 투여 후 소음에 노출시켜 청력 역치의 변화 및 와우의 활성 산소 유리기에 대한 노출 정도를 보았다. 영구적 청력 역치 이동의 경우에 홍삼은 청력 보호 및 회복에 관여하지 못했다. 하지만 일과성 청력 역치 이동의 경우에는 홍삼이 어느 정도의 농도 이상으로 투여 된다면 청력 회복에 효과적으로 작용하는 것으로 밝혀졌다. 향후 홍삼의 난청 억제 효과에 대해 적정 농도 및 투여 방법 등에 대한 후속연구가 뒤따라야 하겠고 인간에서 발생하는 소음성 난청에의 적합성 판정을 위해 보다 장깆거인 소음 노출 기간과 장기적인 홍삼 복용에 대한 연구가 필요하겠다. 또한 홍삼내의 여러 활성물질에 관한 연구를 통하여 보다 효과적인 화합물을 찾기 위한 노력도 동반되어야 할 것이다.

• 한국의학물리학회지:의학물리
• /
• 제11권1호
• /
• pp.19-27
• /
• 2000

본 연구에서는 평탄한 지면 위의 도로 교통소음의 전파특성을 해석하고자 점음원과 쌍극자음원을 모델로 사용하였으며, 연속 지표면 음향임피던스에 대한 초과감쇠를 실험으로 조사하였다 연구결과 수음점이 지표면 가까이 있을 때, 도로 교통소음의 전파특성은 소음 전파경로 상의 지표면 음향임피던스에 크게 영향을 받는 것을 확인하였다. 또한 진행 차량으로부터 측정한 등가에너지레벨의 거리별 감쇠값을 이용하여 등음압곡선을 해석하였다 그리고 도로 교통소음이 인체에 미치는 영향을 조사하고자 초저주파 소음에 대한 응답특성, 깊은 수면율과 잠을 깨는 비율에 대한 연속적인 교통소음의 .효과, 연령과 소음폭로등 다양한 변수에 대하여 청력손실과 청감민감도 변화 등을 고찰하였다 해석결과 과도한 소음은 일시적 청력손실의 원인이며, 폭로가 길어지거나 강력하면 영구적 청력손실의 원인이 될 수 있음을 확인하였다.