Comparison of four task-based measurement indices with full-shift dosimetry in a complicated noise environment

Abstract

This study was conducted to verify the agreement between four task-based measurement indices (TBMs) and full-shift dosimetry in a complicated noise environment. The study involved six production lines and 63 fixed jobs from an automobile wheel manufacturer. The subjects were simultaneously measured by the TBMs and a personal dosimeter, and 158 measurements were completed in total. There were two methods for measuring the level-at-task: average dosimetry noise level (ADL) and direct measure noise level (DML), and two methods for measuring time-at-task: worker diary (WD) and observation diary (OD). As for the differences, Pearson correlation coefficients, paired-samples t-tests, scatter and Bland–Altman plots were undertaken to assess the agreement between TBMs and the dosimeter. The results indicated that the TBMs agreed well with the personal dosimeter; the differences between them ranged from 0.16 to 3.07 dBA. The DML of level-at-task was less than the ADL result of 3.39 dBA and using the DML could cause a systematic error. The results showed that the TBMs from WD were as accurate as the TBMs from OD, and the WD recorded 88% of the task transitions of OD. Our research suggests that the TBMs, which uses ADL and OD, can be a reliable and more feasible as a cost effective strategy for assessing the full-shift noise exposures in practice. The study showed a high degree of agreement between TBM and dosimetry in fixed jobs and complicated noise environments. However it is not clear how well the agreement between TBM and dosimetry is in mobile jobs, and thus requires further studies to assess these environments.