Objective To investigate the noise exposure level of workers in the production line of bottled beverage manufacturing enterprises in a city in the Pearl River Delta, and analyze the influencing factors of high-frequency hearing loss.
Methods Totally 569 workers with at least 1 year of occupational noise exposure time in 7 bottled beverage manufacturing enterprises were studied; the noise exposure level, cumulative noise exposure (CNE), and high-frequency hearing loss (HFHL) of these workers were investigated. The effects of individual and/or occupational characteristics on the HFHL of noise-exposure workers were analyzed with a binary logistic regression model.
Results The noise exposure level ranged from 72.3 to 96.7 dB (A), with 38.49% of the operation posts exceeding the national exposure limit. exposure limit. There were 109 workers with HFHL diagnosed, with prevalence of 19.16%. Obviously, the workers with HFHL(n = 109)were older and had a higher noise level, a higher CNE, and a longer noise exposure time compared with the other workers without HFHL (n = 460; P < 0.01). The most affected workers worked at posts with a high noise level, such as packaging, filling, batching and feeding, and bottle-blowing posts, while the noise level and cumulative noise exposure (CNE) of workers working at filling and bottle-blowing posts were highest (P < 0.05). The results of the logistic regression analysis showed that the risk of noise-exposure workers' HFHL increased by 1.034 and 1.444 times (P < 0.05) for an age increase of 1 year and a CNE increase of 1 dB (A) per year, respectively. Compared with workers working at posts without protective facilities, the risk of HFHL for workers working at posts with protective facilities decreased to 0.074 times (P < 0.05); compared with workers never wearing ear protectors, the risk of HFHL for workers occasionally and often wearing ear protectors was reduced to 0.357 and 0.254 times, respectively (P < 0.05).
Conclusions The risk of a noise hazard at filling and bottle-blowing posts was high in the bottled beverage manufacturing industry. The measures, such as improving the automation of this production process, reducing workers' noise exposure time, and ensuring workers wear ear protectors, should be taken, and the hearing protection program for the workers working in the posts with high noise levels should be strengthened, in order to protect workers exposed to noise against the occurrence of HFHL.