Noise Pollution Effects on Mental Fatigue and Noise Annoyance among Bank Staffs

Noise discomfort is one of the important unpleasant physical parameters in open-plan offices. This study was aimed to investigate the status of noise pollution and its effects on subjective fatigue and noise annoyance among bank staffs. The equivalent sound pressure level (Lpeq.T) of 100 bank employees was determined during the working time. Moreover, the sound pressure level (SPL) in client waiting areas and in the outer area of ​​the studied banks was measured. For evaluating the mental fatigue, the standard Multidimensional Fatigue Inventory (MFI) questionnaire was used. Noise Annoyance Scale (NAS) questionnaire was also applied to study workplace noise annoyance and the subjective impressions of noise intensity. The mean Lpeq.T in the staff workstations, client waiting areas, and the outside area of the studied banks were determined 78.72, 61.14, and 81.32 dB (A), respectively. The mean values ​​of the preferred noise criterion (PNC) and speech interference level (SIL) indices were 58.22 and 70.25, respectively. The results revealed that the feeling of mental fatigue and noise annoyance among bank employees were significantly affected by the Lpeq.T, level (r=0.84 and 0.90, respectively). The findings indicated that the background noise in open-plan offices increased the PNC and SIL indices which can increase the mental discomfort of staff and decrease their job performance in cognitive tasks. Reflective and rigid surfaces increased the SPL scale in the interior area of banks, and therefore it is necessary to modify the internal surfaces in these open-plan offices.