Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing 100191, China.
Chin Med J (Engl). 2011 May;124(9):1346-51.
Task-based measurement (TBM) is a method to assess the eight-hour A-weighted equivalent noise exposure level (L(Aeq.8h)) besides dosimeter. TBM can be better used in factories by non-professional workers and staffs. However, it is still not clear if TBM is equal or similar with dosimeter for L(Aeq.8h) measurement in general. This study considered the measurement with dosimeter as real personal noise exposure level (PNEL) and assessed the accuracy of TBM by comparing the consistencies of TBM and dosimeter in L(Aeq.8h) measurement.
The study was conducted in one automobile firm among 387 workers who are exposed to unstable noise. Dosimeters and TBM were used to compare the two strategies and assess the degree of agreement and causes of disagreement. Worker's PNEL was measured via TBM for noise; the real PNEL was also recorded. The TBM for noise was computed with task/position noise levels measured via sound level meter and workers' exposure information collected via working diary forms (WDF) filled by participants themselves. Full-shift noise exposure measurement via personal noise dosimeters were taken as the real PNEL. General linear model (GLM) was built to analyze the accuracy of TBM for noise and the source of difference between TBM for noise and real PNEL.
The L(Aeq.8h) with TBM were slightly higher than the real PNELs, except the electricians. Differences of the two values had statistical significance in stamping workers (P < 0.001), assembly workers (P = 0.015) and welding workers (P = 0.001). The correlation coefficient of L(Aeq.8h) with TBM and real PNELs was 0.841. Differences of the two results were mainly affected by real PNEL (F = 11.27, P = 0.001); and work groups (F = 3.11, P < 0.001) divided by jobs and workshops were also independent factors. PNEL of workers with fixed task/position ((86.53 ± 8.82) dB(A)) was higher than those without ((75.76 ± 9.92) dB(A)) (t = 8.84, P < 0.01). Whether workers had fixed task/position was another factor on the accuracy of TBM for noise (F = 4.36, P = 0.038).
TBM for noise has acceptable accuracy on workers' PNEL measurement. The accuracy is affected by job categories, workshops and variability of task/position. TBM for noise can yield a relatively conservative result of worker's PNEL in most cases, so it can be used to measure and assess workers' real PNEL.
任务测听（TBM）是一种除了剂量计之外评估 8 小时 A 加权等效噪声暴露水平（L(Aeq.8h)）的方法。TBM 可以更好地被非专业工人和员工在工厂中使用。然而，目前还不清楚 TBM 在一般情况下是否与剂量计一样准确或相似。本研究将剂量计测量的噪声视为实际个人噪声暴露水平（PNEL），并通过比较 TBM 和剂量计在 L(Aeq.8h)测量中的一致性来评估 TBM 的准确性。
本研究在一家汽车公司中进行，共有 387 名暴露于不稳定噪声的工人参与。使用剂量计和 TBM 进行比较，以评估两种策略的一致性，并找出差异的原因。使用 TBM 测量噪声暴露情况，然后用工作日记表（WDF）收集工人的信息。工人的 PNEL 通过个人噪声剂量计进行全工班噪声暴露测量，作为真实 PNEL。建立了一般线性模型（GLM）来分析 TBM 测量噪声的准确性以及 TBM 与真实 PNEL 之间差异的来源。
TBM 测量的 L(Aeq.8h) 略高于真实 PNEL，除了电工。在冲压工人（P < 0.001）、装配工人（P = 0.015）和焊接工人（P = 0.001）中，这两个值之间的差异具有统计学意义。TBM 测量的 L(Aeq.8h) 与真实 PNEL 的相关系数为 0.841。两种结果的差异主要受真实 PNEL 的影响（F = 11.27，P = 0.001）；工作类别（F = 3.11，P < 0.001）和按工作岗位和车间划分的工作小组也是独立因素。具有固定任务/岗位的工人的 PNEL（（86.53 ± 8.82）dB（A））高于没有固定任务/岗位的工人（（75.76 ± 9.92）dB（A））（t = 8.84，P < 0.01）。工人是否具有固定任务/岗位是影响 TBM 测量噪声准确性的另一个因素（F = 4.36，P = 0.038）。
TBM 测量噪声在工人 PNEL 测量方面具有可接受的准确性。准确性受工作类别、车间和任务/岗位变化的影响。在大多数情况下，TBM 测量的工人 PNEL 结果相对保守，因此可用于测量和评估工人的实际 PNEL。
