|LETTER TO EDITOR
|Year : 2022 | Volume
| Issue : 1 | Page : 37
Evaluation of occupational noise levels in the ear canal of exposed workers
Hadi Asady1, Adrian Fuente2, Siamak Pourabdian1, Hossein Ali Yousefi Rizi3, Farhad Forouharmajd1
1 Department of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran
2 École d'orthophonie et d'audiologie, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
3 Department of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Mechanical Engineering, Sogang University, Seoul, Korea
|Date of Submission||01-Jul-2020|
|Date of Acceptance||03-Jul-2020|
|Date of Web Publication||12-Mar-2022|
Department of Occupational Health Engineering, School of Health, Isfahan University of Medical Sciences, Hezar Jarib St., Isfahan
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Asady H, Fuente A, Pourabdian S, Yousefi Rizi HA, Forouharmajd F. Evaluation of occupational noise levels in the ear canal of exposed workers. Int J Prev Med 2022;13:37
|How to cite this URL:|
Asady H, Fuente A, Pourabdian S, Yousefi Rizi HA, Forouharmajd F. Evaluation of occupational noise levels in the ear canal of exposed workers. Int J Prev Med [serial online] 2022 [cited 2022 Oct 3];13:37. Available from: https://www.ijpvmjournal.net/text.asp?2022/13/1/37/339525
This study was conducted due to the prevalence increase of hearing loss in Iran industries, despite the outspread in hearing protection programs. There was also a report from Canada, Oct 8, 2018 on Hearing Disorders, according to a recent study from Work Safe BC, The National Safety Council's Safety Health Magazine. Researchers looked at hearing test data collected by oil and gas employers from 2012 to 2017. They found that, despite an increase in workers reporting they wear hearing protection (to 98% from 94%), the percentage of workers with noise-induced hearing loss grew to 45 from 33. Of the 294 workers affected, 66% were younger than 35.
This cross-sectional study was done on the 60 participants, 30 (50%) males and 30 (50%) females, in the range between 20 and 30 years. White noise levels of 75, 85, and 95 dB at the frequency range 2–8 kHz were used for the stimulus sound pressure levels (SPLs). The research was done based on the ear canal behavior at three SPLs, which was unique among the literature. However, in this study, responses of the ear canal to the SPLs are concentrated on the men and women separately only for showing the effects of the different acoustical structure of ear canal on received noise, and not for indicating the differences between men and women hearing mechanism. Usually, one SPL was used to study the ear canal even the SPL was much lower than the occupational SPL.,,
It seems that the different morphology of men and women ear like the greater volume of men's ear canal compared with that of women made the amplification ability difference.
Sound pressure amplification ability of men's ear canal for the frequency range between 125 and 1000 Hz was less than for lower and higher frequencies also amplification peak was seen at the frequency equal to the 2000 Hz. This finding is consistent with Liu et al. findings. As we know the ear canal volume of women is smaller than men, we expected that the peak of amplification shifted somewhat to higher frequencies in women.
This ability of the ear canal should be considered in the workplace noise evaluations. In such situations because of the resonance ability of ear canal (2 to 8 dB), even under the occupational safe levels, workers may be exposed to unaccepted noise levels in the workplace. The most important note in this study is a higher value of SPL received by hearing system near to eardrum, whereas the sound pressure level measured by a sound level meter (SLM) is near to permitted levels. Since, in some countries, accepted time-weighted average for 8-h exposure with workplaces noises is 85 dB, the resonance ability of ear canal should be considered at occupational hearing protection programs. This is just one of the reasons for the increase in workers' hearing loss, despite the development of hearing protection programs in the industries.
The authors would like to thank all students who cooperated in this study.
Financial support and sponsorship
The authors declare that this research is granted with No. 196162 by Isfahan University of Medical Sciences.
Conflicts of interest
The authors declare that there is no any conflict of interest.
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