Study of the physiological and mental health effects caused by exposure to low-frequency noise in a simulated control room

The purpose of this study was to investigate the physiological and mental health effects caused by exposure to low-frequency noise in typical control rooms and office-like areas. The participants were 35 male students who were exposed to noise at levels of 55, 65, 70, and 75dBA. The N-back test was used at three cognitive performance loads (low workload (n=1), medium workload (n=2), and high workload (n=3) to evaluate working memory simultaneously in an air conditioning chamber in four sessions with a constant level. The electroencephalography, electrocardiogram, and electrooculography were measured using Nexus 4 by Bio traces software (Mind Media Co.). For evaluation of mental fatigue, fatigue visual analog scale, and psycho-physiological indices were also used. The results showed that the losses of physiological and mental health were rapidly increased with exposure to noise levels of 65-75dBA. The results showed that mental fatigue significantly affected heart rate, low- to high-frequency ratios, and electroencephalogram indices such as theta, alpha, as well as eye activities and working memory. The findings confirmed that the mental fatigue caused by low-frequency noise significantly impacted the employees' psycho-physiological and working memory responses. Implementation of the effective interventions to overcome employees' mental fatigue in typical control rooms and office-like areas can improve the health and acoustic comfort and, consequently, the cognitive performance.