Evaluation of Occupational Exposure to Noise and Its Effect on Hearing Loss of Workers in a Cement Factory in Northern Iran

Background and: Industrial noise affects the health of workers and can disrupt the daily communication of workers. The aim of this study is to evaluate occupational exposure and investigate the hearing loss of workers in the two sections of cement mill and material mill of a cement factory in north of Iran. Methods: This was a descriptive study conducted on 52 persons in 2020. At first, the sound measurement was performed with the Casella CEL 450 device in A-weighting network at workers' workplaces based on area-based method. Then, by referring to the medical records and demographic information, the amount of hearing loss in the frequencies of 250-8000 Hz was evaluated. Finally, the results were analyzed using SPSS software version 19. Results: Independent samples T-test showed that the average sound pressure level in the cement mill section (85.50 dBA) is higher than the material mill section (74.38 dBA) (P-value = 0.01). The highest rate of hearing loss was observed at frequencies of 4000 and 8000 Hz. The hearing loss rate was 10 decibels for both ears in the material mill section. No significant difference was observed in the amount of hearing loss in the right and left ears of employees. Conclusion: Noise pollution and hearing loss is common among employees of cement industry. To prevent hearing loss, it is necessary to evaluate and monitor the noise pressure level. Furthermore, engineering measures in the field, using personal protective equipment, as well as adequate training of employees should be conducted.