Humans ; Noise, Occupational ; Occupational Exposure

The objectives of the research are to identify the noise sources and noise level exposure inside C130H aircraft’s hangar; to produce noise mapping; to identify hearing status of C130H aircraft maintenance crews (MC); and suggesting the noise control measure that can be applied. A field survey on noise level by using a digital sound level meter and producing noise mapping. A hearing testing among 63 MC was carried out in Institute of Aviation Medicine, Royal Malaysian Air Force (RMAF). Reviewing the literature and analyzing some control measures to be taken. Hearing test result shown 41.2% of the MC are having hearing impairment. The highest noise level at the central of the hangar is 92.2 dBA (day-time) and 94.2 dBA (night-time) when there is a C130H aircraft starting its engine at 50 meters from the central of the hangar, 95.3 dBA (day-time) and 97.3 dBA (night-time) when there is a C130H aircraft Engine Ground Run at 150 meters from the central of the hangar. Besides, Auxiliary Power Unit is producing the highest noise level which is 125.7 dBA (day-time) and 127.7 dBA (night-time). The application of Personal Protective Equipment (PPE) is the very likely control measure to be taken while engineering control is very costly but can be considered. Since noise is recognized as a hazard, hearing protection as PPE will not be the ultimate solution as a control measure. Hence, the Engineering Control must be identified and studied to be implemented as an ultimate solution to control the noise hazard in long term duration.
C130H aircraft ; maintenance crew ; noise exposure

Humans ; Noise, Occupational ; adverse effects ; Occupational Exposure ; standards

Objective: To understand the harm degree of underground noise and provide basis for noise control. Methods: In November 2019, 13 typical coal mines in Sichuan Province were selected as the research objects, and a total of 1203 sites and 609 jobs of noise exposure were investigated. Results: The noise intensity P75 >80 dB (A) was measured. The noise intensity of the inspection place of the air compressor is >86 dB (A) , the noise intensity of the inspection place of the gas drainage and the operation place of the main fan is between 80-85 dB (A) . Conclusion: Besides the harm of dust, noise exposure should also be paid attention to, and the measures of sound absorption and sound insulation should be taken or personal protection should be strengthened.
Coal ; Coal Mining ; Dust/analysis* ; Noise ; Occupational Exposure

OBJECTIVETo investigate the noise hazards in open quarries and to provide a basis for further control of noise hazards.

METHODSAn investigation was performed during 2010 to 2011 among all open quarries in Deqing County of Zhejiang Province, China. The investigation included basic information of the quarries, the occupational health situation and noise intensity at the workplace, and the hearing loss of workers exposed to noise in quarry enterprises. The hearing test results were evaluated based on the Diagnostic criteria of occupational noise-induced hearing loss (GBZ 49-2007).

RESULTSA total of 25 enterprises with open quarries were investigated, of which only 30.4% (17/56) workplaces met the national standard. The median noise level was 92.5 dB (A). Fifty-four (10.6%) out of 508 workers in the 25 enterprises were diagnosed with binaural hearing loss in the initial physical examination, with 18.3% (93/508) under surveillance. The rate of normal hearing among crushing workers, mechanists, drilling workers, and blasting workers ranged between 27.6% and 41.4%, which was significantly lower than that among workers exposed to slight noise hazards (80.0%) or other workers (63.7%) (P < 0.05). With increasing working years, the binaural hearing loss of crushing workers became serious.

CONCLUSIONSerious occupational noise hazards existed in most jobs in open quarries, with crushing workers, mechanists, drilling workers, and blasting workers most seriously jeopardized. Among crushing workers, those working in the first-line or unprotected second?line positions suffered more than the others. Further measures should be taken by the supervision department and the enterprises to control the noise hazards in open quarries.

OBJECTIVETo compare the difference of effects on hearing injury between punching machine noise and steady state noise.

METHODSThe subjects of present study were 100 workers, included 38 workers exposed to punching machine noise from forging shops and 62 workers exposed to steady state noise from drawbench or abrasive dust workshops. The individual noise dosimetries were used to detect noise that workers exposed, and cumulative noise exposure (CNE) was then calculated. On the basis of GBZ 49-2007, the worker hearing was tested, and the results were assessed.

RESULTSThere were no differences of CNE between group exposed to punching machine noise and group exposed to steady state noise. The hearing loss rate (55.3%) at high frequency in workers exposed to punching machine noise was significantly higher than that (32.3%) in workers exposed to steady state noise (P < 0.01). CNE and the hearing loss rate at high frequency showed dose-response relationship (P < 0.01).

CONCLUSIONwhen the exposure levels of workers were similar, the hearing injury induced by punching machine noise may be significantly higher than that induced by steady state noise.

OBJECTIVE: To compare the image quality of low-tube-voltage and low-iodine-concentration-contrast-medium (LVLC) computed tomography urography (CTU) with iterative reconstruction (IR) with that of conventional CTU. MATERIALS AND METHODS: This prospective, multi-institutional, randomized controlled trial was performed at 16 hospitals using CT scanners from various vendors. Patients were randomly assigned to the following groups: 1) the LVLC-CTU (80 kVp and 240 mgI/mL) with IR group and 2) the conventional CTU (120 kVp and 350 mgI/mL) with filtered-back projection group. The overall diagnostic acceptability, sharpness, and noise were assessed. Additionally, the mean attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM) in the urinary tract were evaluated. RESULTS: The study included 299 patients (LVLC-CTU group: 150 patients; conventional CTU group: 149 patients). The LVLC-CTU group had a significantly lower effective radiation dose (5.73 ± 4.04 vs. 8.43 ± 4.38 mSv) compared to the conventional CTU group. LVLC-CTU showed at least standard diagnostic acceptability (score ≥ 3), but it was non-inferior when compared to conventional CTU. The mean attenuation value, mean SNR, CNR, and FOM in all pre-defined segments of the urinary tract were significantly higher in the LVLC-CTU group than in the conventional CTU group. CONCLUSION: The diagnostic acceptability and quantitative image quality of LVLC-CTU with IR are not inferior to those of conventional CTU. Additionally, LVLC-CTU with IR is beneficial because both radiation exposure and total iodine load are reduced.
Commerce ; Contrast Media* ; Humans ; Iodine ; Noise ; Prospective Studies ; Radiation Exposure ; Signal-To-Noise Ratio ; Urinary Tract ; Urography*

According to the research on the pathogenesis of the hidden hearing loss in recent years, the occurrence of the hidden hearing loss is earlier than the permanent hearing threshold shift. This paper reviews the risk factors of hidden hearing loss, the pathogenesis of noise-induced hidden hearing loss, and the detection methods of hidden hearing loss. To explore the significance of hidden hearing loss in occupational health surveillance, and to provide reference for hearing protection of workers exposed to noise and hearing loss early in the future.
Hearing ; Hearing Loss, Noise-Induced ; Humans ; Noise, Occupational ; Occupational Diseases ; Occupational Exposure ; Occupational Health

To determine the recovery time from noise-induced temporary threshold shift (TTS), a prospective field study was conducted at three worksites where workers are known to be exposed high level of noise. Subjects were selected according to answers on a questionnaire which inquired about otological history and previous noise exposure, including avocational, military and occupational exposures. After excluding employees with past otologic problems, recent exposure to high level noise, and under medications, total 92 employees participated in the study. Among 92 participants, complete consecutive audiometric examinations were carried out at 0~2 hours, 5~7 hours, 14~16 hours after worktime noise exposure on 26 participants wearing hearing protectors and 22 participants wearing no protective devices. The difference between the hearing level 0~2 hours after noise exposure and 5~7 hours is statistically significant by paired t-test(p<0.01). The median recovery times calculated from the data of 22 participants wearing no protective hearing devices are 15.6 hours at 4000 Hz, and 7.7 hours, 10.3 hours, 8.4 hours at 1000 Hz, 2000 Hz and 8000 Hz respectively. These data suggest that when measuring the pure tone audiometry for noise exposed workers, at least 16 hours noise-free interval is required.
Audiometry ; Hearing ; Hearing Loss, Noise-Induced ; Humans ; Military Personnel ; Noise ; Occupational Exposure ; Prospective Studies ; Protective Devices ; Questionnaires ; Workplace

To determine the recovery time from noise-induced temporary threshold shift (TTS), a prospective field study was conducted at three worksites where workers are known to be exposed high level of noise. Subjects were selected according to answers on a questionnaire which inquired about otological history and previous noise exposure, including avocational, military and occupational exposures. After excluding employees with past otologic problems, recent exposure to high level noise, and under medications, total 92 employees participated in the study. Among 92 participants, complete consecutive audiometric examinations were carried out at 0~2 hours, 5~7 hours, 14~16 hours after worktime noise exposure on 26 participants wearing hearing protectors and 22 participants wearing no protective devices. The difference between the hearing level 0~2 hours after noise exposure and 5~7 hours is statistically significant by paired t-test(p<0.01). The median recovery times calculated from the data of 22 participants wearing no protective hearing devices are 15.6 hours at 4000 Hz, and 7.7 hours, 10.3 hours, 8.4 hours at 1000 Hz, 2000 Hz and 8000 Hz respectively. These data suggest that when measuring the pure tone audiometry for noise exposed workers, at least 16 hours noise-free interval is required.
Audiometry ; Hearing ; Hearing Loss, Noise-Induced ; Humans ; Military Personnel ; Noise ; Occupational Exposure ; Prospective Studies ; Protective Devices ; Questionnaires ; Workplace