Noise Intensity and Its Impact on The Perception and Concentration Level Among Forest Harvesting Workers in Industrial Forest Plantation, North Sumatera, Indonesia

Abstract

Background: Noise has the potential to affect the comfort and health of workers. The objective of this research was to find out the effect of noise caused by timber harvesting process using chainsaw on the concentration of workers in an industrial forest plantation.

Methods: This cross-sectional study included 20 respondents which consisted of 10 chainsaw operators/helpers and 10 non-chainsaw operators. All respondents were exposed to the sound of chainsaw in three different conditions (idle, half gas and racing conditions) with and without personal protective equipments (PPE). The sound intensity produced by the chainsaw and the noise received by the respondents were measured using sound level meter. Respondents’ perception toward noise was recorded using Likert scale. Respondents’ concentration level was assessed by giving 25 math-questions that must be answered within 10 minutes. Wilcoxon sign rank test was used to analysed paired data.

Results: the average sound intensity received by respondents’ left and right ear were lower than the average of sound intensity produced by the chainsaw. The average sound intensity produced by the chainsaw in idle condition was 101.3 dB, while that received by the right ear was 81.36 dB and the left ear was 82.86 dB. When the chainsaw was in half gas condition,  the average sound intensity produced was 111 dB while that received by the right ear was 95.83 dB and the left ear was 97.11 dB. In racing condition, the average sound intensity produced by the chainsaw was 124.7 dB while that received by the right ear was 106.2 dB and the left ear was 107.7 dB, respectively. The use of earmuff leads to better perception towards noise when compared with the use of earplug and the absent of any personal protective equipment (PPE). Wilcoxon test result showed that noise did not have significant impact on the concentration level of chainsaw operators, whilst the contratry result is true for non-chainsaw operators.

Conclusion: The research indicated that although the noise produced by the chainsaw machine was considered as noisy for both chainsaw operators and non-chainsaw operator, it did not give significant effect on the concentration level of chainsaw operators and only affects the non-chainsaw operators. Therefore, given that the non-chainsaw operators were still affected by the noise, noise control measures are still needed to ensure occupational safety and health for the workers.