Occupational Noise Exposure And Hearing Loss Prevalence Among The Grass Cutters Of USM, Penang
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Date
2012-05
Authors
Ahmad, Mohammad Zaip
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Exposure to excessive noise can cause many adverse health effects including hearing loss. Even though hearing loss from noise exposure has been recognized since the industrial revolution and the noise legislations in the work place has been enacted over the last two decades, but it remains as one of the most prevalent occupational health problems in many countries of the world. In Malaysia, little is known about noise exposure and hearing loss among grass cutters who operate the back pack grass cutting machine. The main purpose of this study is to determine the level of noise exposure from the grass cutting machine and the prevalence of hearing loss among the workforce of USM grass cutters. This study involved 42 grass cutters, and 28 ex-grass grass cutters of the Development Department as the noise exposed workers and 45 of non-noise exposed workers were selected among the supporting and administrative workers of various departments in USM, Penang. The workers’ hearing threshold levels (HTLs) for both ears were assessed by using the audiometer at the frequencies of 0.25 to 8 kHz in a soundproof booth. Personal noise exposure levels of grass cutters and administrative workers were measured by using noise dosimeters. Information regarding the socio-demographic of workers, present and past medical history of hearing problems, use of ototoxic chemicals, hobbies, past noise exposures and other risk factors were obtained using a self-administrated questionnaire. The hearing loss prevalence was determined based on HTL of workers in either ear which is shifted by more than 25 dB(A) at any test frequency. The grass cutters were exposed to an average noise level of 93.85 dB(A) (minimum = 86.00 dB(A) and maximum = 114.50 dB(A)) and the non-noise exposed workers were exposed to an average noise level of 70.40 dB(A) (minimum = 62.20 dB(A) and maximum = 79.4 dB(A)). 7.1% and 69% of the grass cutters were exposed to the noise level exceeding the Malaysian Factories and Machinery (Noise Exposure) Regulations, 1989 (F&MNR) PEL of 90 dB(A) and United State National Institute for Occupational Safety and Health (NIOSH) REL of 85 dB(A) for 8-hour exposure, respectively. None of the non-noise exposed workers were exposed to noise levels that exceeded the NIOSH REL, as well as PEL of F&MNR.
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Keywords
Occupational noise exposure and hearing loss , among the grass cutters of USM, Penang