[Estimation model of individual noise exposure dose based on spatial distribution of workplace noise level]

Objective: To develop an individual noise exposure dose estimation model based on spatial distribution of noise in order to provide reference for occupational health management and hearing loss risk assessment caused by noise in workplace. Methods: From July 2018 to October 2019, 10 noise-exposed positions and 48 employees in 3 high-noise workplaces of a manufacturing enterprise in Sichuan Province were selected as the research objects. Occupational health survey, fixed-point measurement of workplace noise and individual noise measurement were used to obtain noise intensity and employee exposure information. The mean noise intensity and the corresponding exposure time were weighted to estimate the individual noise exposure dose estimation model based on the spatial distribution of workplace noise, and the paired t-test was used to evaluate the accuracy of the individual noise exposure dose estimate (8 h equivalent sound level, L(EX, 8h)) based on the spatial distribution of workplace noise and the measured value of individual noise exposure dose. And the least square regression model was used to correct it. Results: The daily noise exposure dose of 44 (91.7%) of 48 workers in 10 types of work in 3 sites of the manufacturing enterprise exceeded the standard, and the maximum noise exposure intensity was up to 108.3 dB (A). The measured value of individual noise exposure dose was higher than L(EX, 8h), and the difference was statistically significant (P<0.001). The noise difference distribution was mostly positive and symmetrical (P=0.958). The measured noise exposure dose of 6 out of 10 work types in 3 sites was higher than L(EX, 8h) (all P<0.05), and there was a linear correlation between the measured dose and L(EX, 8h) (r=0.373, P<0.05). Considering the influence of systematic error and the construction, diagnosis and screening of adaptive assessment model, an individual noise exposure dose estimation model based on the spatial distribution of workplace noise was finally obtained: y=0.574x+45.250, where y was the measured value of individual noise exposure dose, x was L(EX, 8h) value. Conclusion: The high noise hazard in manufacturing industry is more serious, and the noise exposure assessment of single fixed-point detection is relatively rough. The individual noise exposure dose estimation model based on the spatial distribution of workplace noise has a certain role in the occupational health management of workplace noise hazard in manufacturing industry.