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

Introduction: 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. Materials and Methods: 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. Results: 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. Conclusion: In conclusion, the rate of hearing loss among tile workers was high, hearing loss was more frequently seen in right ear than left ear.