Brueck Scott E, Prince Panaccio Mary, Stancescu Daniel, Woskie Susan, Estill Cheryl, Waters Martha
Hazard Evaluations and Technical Assistance Branch, Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, MS: R-11, Cincinnati, OH 45226, USA;
Ann Occup Hyg. 2013 Nov;57(9):1091-104. doi: 10.1093/annhyg/met035. Epub 2013 Jul 12.
This study used a task-based approach to reconstruct employee noise exposures at two large automotive manufacturing plants for the period 1970-1989, utilizing historic noise measurement data, work history records, documented changes in plant operations, focus group discussions, structured interviews with long-tenure employees, and task-based job profiles. Task-based job noise exposure profiles were developed in the 1990s when the plants conducted task-based noise monitoring. Under the assumption that tasks and time-at-task profile within jobs did not change over time, these profiles were applied to historic jobs. By linking historic noise exposure measurements to job tasks, this approach allowed task-based reconstructed noise exposure profiles to capture variability of daily noise exposures. Reconstructed noise exposures, along with task-based noise exposure measurements collected at each plant during the 1990s, were analyzed to examine time trends in workplace noise levels and worker noise exposure. Our analysis of noise exposure trends revealed that noise levels for many jobs declined by ≥3 dBA from 1970 to 1998 as operational and equipment changes occurred in the plants and some noise control measures were implemented, but for some jobs, noise levels increased in the mid- to late 1990s, most likely because of an increase in production at that time. Overall, the percentage of workers exposed to noise levels >90 dBA decreased from 95% in 1970 to 54% in 1998 at one of the plants and decreased from 36% in 1970 to ~5% in 1999 at the other plant. These reductions indicate a degree of success for the hearing conservation program. However, the actual number of employees with noise exposure >90 dBA increased because of a substantial increase in the number of production employees, particularly in jobs with high noise levels, which shows a hearing conservation program challenge that companies face during periods of increased production. Future analysis of hearing levels in these plant populations will help determine whether noise level reduction translates into decreased hearing loss at these plants.
本研究采用基于任务的方法，利用历史噪声测量数据、工作经历记录、工厂运营的记录变化、焦点小组讨论、对长期任职员工的结构化访谈以及基于任务的工作概况，重建了1970 - 1989年期间两家大型汽车制造工厂员工的噪声暴露情况。基于任务的工作噪声暴露概况是在20世纪90年代工厂进行基于任务的噪声监测时制定的。在假设工作中的任务和任务执行时间概况不会随时间变化的情况下，这些概况被应用于历史工作。通过将历史噪声暴露测量与工作任务相联系，这种方法使得基于任务重建的噪声暴露概况能够捕捉每日噪声暴露的变异性。对重建的噪声暴露以及20世纪90年代在每个工厂收集的基于任务的噪声暴露测量数据进行了分析，以研究工作场所噪声水平和工人噪声暴露的时间趋势。我们对噪声暴露趋势的分析表明，随着工厂运营和设备的变化以及一些噪声控制措施的实施，从1970年到1998年，许多工作的噪声水平下降了≥3分贝，但对于一些工作，噪声水平在20世纪90年代中期至后期有所上升，最有可能是因为当时产量增加。总体而言，一家工厂中暴露于噪声水平>90分贝的工人比例从1970年的95%降至1998年的54%，另一家工厂从1970年的36%降至1999年的约5%。这些下降表明听力保护计划取得了一定程度的成功。然而，由于生产员工数量大幅增加，尤其是在高噪声水平工作岗位上，噪声暴露>90分贝的员工实际数量增加了，这显示了公司在产量增加期间面临的听力保护计划挑战。对这些工厂人群听力水平的未来分析将有助于确定噪声水平降低是否会转化为这些工厂听力损失的减少。
