Effect of Unmeasured Time Hours on Occupational Noise Exposure Assessment in the Shipbuilding Process in Korea.

Jaewoo Shin,Hyunwook Kim,Seokwon Lee,Kyoungho Lee

doi:10.3390/ijerph18168847

Abstract

Occupational noise is known to be one of the most hazardous risk factors, frequently exceeding the exposure limit thus causing hearing loss and other health outcomes among many field workers in various industries and workplaces. This study aims to characterize the levels of occupational noise exposure during the daily working hours and break periods (sampling preparation and lunch break), identify work-related characteristics affecting the noise exposure levels when including or excluding the break periods and finally determine the most effective approach for occupational noise exposure assessment by using the Korean and U.S. OSHA’s guidelines. A total of 1575 workers employed by a large shipbuilding company participated in this study, and the historical exposure datasets of noise dosimeters, collected from 2016 to 2018, were classified by characteristics. A threshold level (TL) for the noise dosimeter was set as a value of 80 dBA during the break periods, including the preparation time for sampling instruments and one hour for the lunch break. The shipbuilding workers were exposed to high levels of occupational noise during the break periods, especially for those working in heating, grinding, and power processes in the painting-related departments. Out of 1575 samples, most cases were related to the preparation time (N = 1432, 90.9%) and lunch break (N = 1359, 86.9%). During the break time, the levels of noise exposure were measured depending on task-specific characteristics. When including the break time, the noise levels increased by approximately 1 dBA during the break, combining 0.8 dBA in the lunch hours and 0.2 dBA for the preparation of the sampling instrument. When excluding the break time, the levels of noise exposure collected using a Korean Occupational Safety and Health Administration (KOSHA) guide tended to be underestimated compared to those using the U.S. OSHA method. When including the break times, the proportion of noise exposure levels exceeding the compliance exposure limit declined from 37.9% to 34.5%, indicating that the break times might affect the decrease in the noise exposure levels. Taken together, shipbuilding workers could possibly be exposed to much greater amounts of noise exposure during break times in the shipbuilding processes, and the noise exposure levels in the department of painting were high. Therefore, it is recommended that industrial hygienists collect exposure monitoring data of occupational noise one hour after their job tasks begin and then consecutively monitor the noise exposure levels for at least 6 h including the break periods for each day.

Highlights

Occupational noise exposure is one of the most important risk factors causing hearing loss among workers in a variety of industries and workplaces, and approximately 16% of manufacturing workers suffer from hearing loss with serious consequences [1], including irritation, sleep disorders, daytime sleepiness, metabolic syndrome, hypertension, and cardiovascular disease, due to acute or chronic exposure to occupational noise [2,3,4,5,6,7]
This study provides evidence that there is underestimation in the results using the Korean Occupational Safety and Health Administration (KOSHA) guideline, which suggests that the break periods be taken out of the daily monitoring period when conducting noise exposure assessment in the shipbuilding processes in Korea
These results indicate that the source of noise exposure exceeded the noise exposure limit during the break time during shipbuilding processes, and workers were indirectly exposed to noise generated during the break time when they were not wearing hearing protection equipment such as earplugs

Summary

Introduction

Occupational noise exposure is one of the most important risk factors causing hearing loss among workers in a variety of industries and workplaces, and approximately 16% of manufacturing workers suffer from hearing loss with serious consequences [1], including irritation, sleep disorders, daytime sleepiness, metabolic syndrome, hypertension, and cardiovascular disease, due to acute or chronic exposure to occupational noise [2,3,4,5,6,7]. In. Korea, occupational noise is known to be one of the most hazardous workplace risk factors, frequently exceeding the occupational exposure limit (OEL) during quantitative exposure assessments in a large number of industries and workplaces in the past [8,9,10]. To prevent occupational hearing loss, it is important that a comprehensive evaluation be performed to quantitatively characterize all levels of cumulative noise exposure during a full shift of fixed jobs, identifying the task-based exposure profiles for individual workers [11].

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Discussion

Conclusion