Evaluation of noise pollution and noise-induced hearing loss in workers of a ceramic industry

Noise-induced hearing loss (NIHL) is a major problem in industrialized and developing countries. Trend of industrialization and lack of proper protective equipment lead to an increased frequency of noise-related disorders especially NIHL. This study was conducted to investigate noise pollution and the frequency of NIHL in workers of one of the ceramic industries.
In a descriptive cross-sectional study, 155 tile workers were studied in 2015. Mean of age and working experience in participants was 29.45± 6.8 and 5.3 ±3.65 years, respectively. Sound pressure level in different sections of ceramic industry were measured using Brüel & Kjær sound level meter. Pure tone audiometry of air conduction was performed in both ears at frequencies 0.5, 1, 2, and 4 kHz. Hearing threshold higher than 25 dB at different frequencies was defined as hearing loss.
Mean of hearing threshold was 20.06 ±7.64 dB in right ear and 17.46 ±8.7 dB in left ear. Total hearing threshold was 17.9 ±8.04 db. About 18.7% of subjects suffered from NIHL in the right ear and 10.3% in the left ear. A significant relationship was found between work experience, job, lack of using proper protective equipment and hearing loss.
In conclusion, the rate of hearing loss among tile workers was high, hearing loss was more frequently seen in right ear than left ear.