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

Abstract <strong>Background:</strong> 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.**摘要** <strong>背景：</strong>噪声可对劳动者的舒适度与健康造成不良影响。本研究旨在探究使用链锯（chainsaw）进行木材采伐作业产生的噪声，对工业人工林作业工人专注力的影响。 <strong>方法：</strong>本横断面研究共纳入20名受试者，其中10名为链锯操作者/辅助人员，10名为非链锯操作者。所有受试者在三种工况（怠速、半油门、满油门）下，分别佩戴和未佩戴个人防护装备（Personal Protective Equipment, PPE）时暴露于链锯噪声中。采用声级计（sound level meter）测量链锯产生的声强及受试者所接收的噪声强度。通过李克特量表（Likert scale）记录受试者对噪声的感知情况。评估受试者专注力水平时，要求其在10分钟内完成25道数学题。配对数据采用Wilcoxon符号秩检验进行分析。 <strong>结果：</strong>受试者左右耳接收的平均声强均低于链锯产生的平均声强。链锯怠速工况下的平均声强为101.3 dB，受试者右耳接收的平均声强为81.36 dB，左耳为82.86 dB；半油门工况下，链锯产生的平均声强为111 dB，右耳接收声强为95.83 dB，左耳为97.11 dB；满油门工况下，链锯产生的平均声强为124.7 dB，右耳接收声强为106.2 dB，左耳为107.7 dB。与使用耳塞及未佩戴任何个人防护装备相比，佩戴耳罩时受试者对噪声的感知效果更佳。Wilcoxon符号秩检验结果显示，噪声对链锯操作者的专注力水平无显著影响，而非链锯操作者则呈现相反结果。 <strong>结论：</strong>本研究表明，尽管链锯产生的噪声被链锯操作者与非链锯操作者均判定为嘈杂，但该噪声仅对非链锯操作者的专注力产生影响，而对链锯操作者的专注力无显著作用。因此，鉴于非链锯操作者仍受噪声影响，仍需采取噪声控制措施，以保障劳动者的职业安全与健康。