Alternative noise exposure metrics among construction workers

Abstract

There continues to be some uncertainty in the choice of noise exposure metrics for assessing the risk of hearing damage. In particular, the Leq, based on a 3 dB exchange rate (ER) and the Lavg, which uses a 5 dB ER are both in use, as are various metrics representing exposure peaks. This paper presents an analysis of a large database of noise exposures among construction workers, comparing several noise metrics, and their application to a cohort of construction workers, followed audiometrically over a three year period. Metrics examined were the Lavg, Leq, and Lmax, expressing average levels. Two novel metrics were derived from these monitored metrics, Leq/Lavg, and Lmax/Leq, as measures of exposure variability and peakiness. A total of 730 workshifts, including data on 361 492 min of exposure to workers in 9 trades were examined. Correlations between average metrics (Leq, Lavg, Lmax) are generally very high, while the variability metrics are poorly correlated with average levels and with each other, indicating that they characterize different aspects of exposure. The task-specific estimates of individual exposure, using the various metrics, were applied to the cohorts work history and their effects on changes in hearing were assessed.