The effect of noise exposure on mental workload, noise sensitivity and general and mental health of overhead crane operators in one of the Steel Industries in south of Iran

Introduction: Overhead cranes play a vital role in guiding steel industries and maintaining their normal condition. These machines are operated by humans and pose a great risk of accidents that may occur due to mistakes made by operators. According to the mentioned contents, the non-negligible effects of noise on the physical and mental health of people in the work environment, the complexity and sensitivity of overhead crane operators, as well as the serious injuries caused by the error of this task, this study aimed at the effect of exposure to noise on mental workload, noise sensitivity and general and mental health of overhead crane operators in one of the steel industries in southern Iran. 
Materials and Methods: This study was conducted in two phases. In the first phase, the worker's exposure to the sound level was carefully evaluated. In this way, the sound pressure leveling was done during the operator's duty and in the crane cabin according to the recommendation of ISO 9612. In the second phase of the research, after determining the level of exposure of overhead crane operators to noise, noise sensitivity questionnaires, mental assessment of exposure to noise conditions, and general health questionnaires were distributed and subjected to statistical analysis. Statistical analysis of data was done using SPSS version 22 software. Using a one-way analysis of variance, independent t-test, and Pearson's correlation coefficient, the relationship between different factors was investigated. In this study, a significance level of 5% was considered. 
Results: The average equivalent level of exposure of overhead crane operators for 8 hours is 76.4 dB and the maximum and minimum equivalent levels of 8-hour exposure, respectively; 84 and 68.2 dB were obtained. The results of this study showed that there is a significant relationship between the variables of gender, marital status, and working hours with noise sensitivity and the variables of gender, education, a mental crisis in the last month and second job with mental load, and the variable of mental crisis in the last month with general health (P<0.05). Pearson's correlation coefficient was used to investigate the relationship between noise sensitivity, mental load, and general health with sound. The results showed, there is no significant relationship between noise sensitivity, mental load, and general health with sound (P> 0.05). There is a negative or inverse relationship between noise sensitivity and general sound health. This means that with the increase in volume, sensitivity to sound and general health will decrease and vice versa. 
Conclusion: The results of this research can provide the necessary platform to improve the working conditions of overhead crane operators to prevent the occurrence of inconveniences and problems of inaudible noise in values ​​less than 85 dB.