Objective: To assess the efficacy of silicone earplugs in protecting workers exposed to noise in a typical manufacturing environment, and to provide training interventions for workers who do not achieve the anticipated noise reduction levels, as well as examining the spectral characteristics of earplug attenuation. Methods: From June to August 2022, a total of 294 noise-exposed workers in two manufacturing enterprises equipped with the same type of earplug were studied by cluster sampling method, by conducting questionnaire surveys, collecting data, fitting tests, and providing trainings, the current noise exposure levels of workers in the industry as well as the perception about the earplug were understood. Additionally, the attenuation before and after intervention in workplace were measured, the spectral characteristics of noise reduction were were described and compared. Results: The percentage of workers with Personal Attenuation Rating (PAR) of 0 is 32.7% (96/294), and the baseline pass rates are all below 60%. There were no significant differences in pass rates based on gender, age, noise exposure, education level, or cognition of earplug effectiveness. After adjusting the way that earplugs are worn or changing the type of earplugs, all workers were able to meet their noise reduction requirements. The median PAR improvement for both companies is above 10 dB. The noise attenuation of the earplug vary with frequency, with lower attenuation at 4 000 Hz and higher attenuation at 8 000 Hz, showing some deviation from the nominal values. Conclusion: The difference between the actual sound attenuation value of earplugs and the nominal value is related to the noise frequency. When using silicone earplugs, attention should be paid to the spectral composition of the noise in the workplace.
目的： 评估制造业企业噪声暴露工人佩戴某预制型硅胶耳塞的防护效果，对未达到预期降噪水平的工人进行培训干预，并了解耳塞衰减的频谱特征。 方法： 于2022年6至8月，选择两家配发同种耳塞的制造企业，采用整群抽样方法选择294名噪声暴露岗位工人作为研究对象，通过问卷调查、资料收集、声衰减测试及培训干预，对企业工人声暴露现状及对佩戴耳塞的主观认知、耳塞佩戴的实际衰减及干预后的衰减及硅胶耳塞降噪的频谱特征进行描述与组间比较。 结果： 基线个人声衰减值（personal attenuation rating，PAR）值为0的工人占32.7%（96/294），两企业PAR基线通过率均不足60%；不同性别、年龄、接噪工龄、受教育程度及工人对耳塞主观认知差异的PAR基线通过率差异均无统计学意义（P>0.05）。干预后两企业工人PAR提升值中位数均>10 dB；不同频率的PAR差异有统计学意义（P<0.05）；PAR与标称值在4 000 Hz处差距较大。 结论： 耳塞的实际声衰减值与标称值之间的差值与噪声频率有关，使用硅胶耳塞时需要关注场所噪声的频谱成份。.
Keywords: Attenuation spectrum; Earplug; Noise; Personal attenuation rating.