ABSTRACT
Objective To evaluate the noise hazard level of a coal mining enterprise, and identify high-risk operation types and people, and to provide a basis for preventing and controlling the health damage caused by noise. Methods A large coal mining enterprise in Shaanxi Province was selected as the research object. The noise monitoring data of the coal mine over the years was used to calculate the noise exposure matrix of each post in the enterprise, and the classification of occupational hazards at workplaces (GBZ/T 229.4-2012) was used to assess the occupational health risk levels. Results Among the 22 noise-exposed positions in the enterprise, the 8-hour working day equivalent sound level in positions of shearer driver, horseshoe driver, crusher driver, shuttle driver, relaxation screen driver, and grading screen driver were all higher than the occupational exposure limit of noise. In 2021, the noise exposure levels of shearer drivers, crusher drivers, and coal-selecting workers were all higher than 90 dB (A), and the occupational hazard level was moderate hazard level. In addition, the noise exposure levels of most other jobs also exceeded the occupational exposure limit. Conclusion The noise hazards in the coal mine industry are mainly concentrated in the posts of the coal mining system, tunneling system, and screening workshop. Among them, the shearer driver, the crusher driver, and the coal preparation workers have higher noise exposure levels. It is recommended to take corresponding noise reduction measures and strengthen the protection level to reduce the noise exposure risk of workers.
ABSTRACT
ObjectiveTo explore the relationship between the occupational noise exposure and arteriosclerosis in mechanical manufacturing workers. Methods A total of 453 employees of a machinery manufacturing enterprise were selected as the study subjects using the judgment sampling method. The noise exposure levels in their workplaces were measured, and their cumulative noise exposure (CNE) was assessed based on the type of job-noise exposure matrix and occupational hazard exposure history. Pure-tone audiometry was performed on the research subjects, and their brachial-ankle pulse wave velocity (baPWV) was measured. Results The CNE was (91±11) dB(A) per year and the median baPWV was 1 278.0 cm/s in the research subjects. The results of the generalized linear regression model analysis showed that for every one dB(A) per year increase in CNE, the baPWV of the general population increased by 0.20% ［95% confidence interval (CI) 0.10%-0.30%, P<0.01］, with an increase of 0.17% in males (95%CI 0.06%-0.28%, P<0.01) and 0.28% in females (95%CI 0.07%-0.49%, P<0.01). Using the hearing loss as an outcome indicator for high intensity noise exposure, the results showed that baPWV increased by 7.04% (95%CI 2.42%-11.87%, P<0.01) in individuals with bilateral hearing loss, and by 9.84% and 6.53% (95%CI 3.07%-17.07% and 2.13%-11.11%, all P<0.01) in individuals with elevated high-frequency hearing thresholds in both ears and in either ear, respectively. There was no significant association in elevated speech-frequency hearing thresholds and arteriosclerosis (P>0.05). Conclusion Occupational noise exposure may increase the risk of arteriosclerosis.