Evaluation of Noise Levels and Noise-induced Hearing Loss among Lumber Mill Workers: A Case Study at Nakrua Sub-district, Maetha distict, Lampang province

Abstract

Introduction: This is a cross-sectional study due to the fact that lumber mill is one of essential export industry to develop country. Commonly, lumber mills require workers in every manufacturing process, as the result, the workers might expose to any hazard environments. One of those, is noise that can be a major risk of occupational hearing loss.
Objective: To evaluation of noise levels and noise-induced hearing loss among lumber mill workers in 8 working hours, and to study the personal factor and work related to hearing loss.
Method: Study in lumber mill workers 30 subjects from 3 factories, sound level meter from 3M (SP-DL) was used to evaluate noise levels, and SibelSound 400 of the audiometer was used to assess the audiometry. Frequency, percent and mean was analyzed in demographic. Chi-square was analyzed in characteristic and environment of work.
Result: The results of the study showed that sound levels were exceeded standard (85 dBA) in Air jig machine, Router machine, Band saw machine, and Electric wood planers are 89.3 dBA, 87.9 dBA, 87.8 dBA, and 87 dBA, respectively. Also, it was showed that the maximum noise level was found in the frequency range of 2,000 Hertz. The study revealed that the workers were diagnosed with noise-induced hearing loss in the frequency of 500-2000 Hz. Factors that were significantly associated with noise-induced hearing loss included age (p - value = 0.011) and education (p - value = 0.025)
Conclusion: The results of this study could be used to recommend the workplace to conduct health surveillance program in lumber mill and, also the continous of noise coservertion annaully.