Investigation of Relationship between Noise Annoyance and Neurophysiological Responses of Drivers in Exposure to Tractor Sound

Sound as a detrimental factor in working environments can create annoying conditions for people in addition to physical problems. Therefore, in addition to evaluating quantitative parameters such as pressure levels, it is absolutely necessary to study the quality parameters of the sound in the work environment. In this descriptive-analytic research, the sound of 285 MF tractor was recorded. Then, the EEG of five drivers were recorded in the pre-driving state and then when driving with the tractor in four different engine speed. The psychoacoustic annoyance model was used to assess the annoyance of tractor drivers. Then means were compared with Duncan comparison test at 5% probability level and the correlation between psychoacoustic acoustic and alpha and beta bands was determined. The results of ANOVA showed that different levels of engine speed on psychoacoustic annoyance were significant at 1% probability level. The results also showed a decrease in the amplitude of the alpha band, as well as an increase in the beta band amplitude due to increased engine speed. Regression results showed that there is a high correlation between the two alpha and beta bands and the psychoacoustic annoyance, so that the detection coefficient was 0.966 and 0.998, respectively, for the two bands alpha and beta. This study showed that changes in the quality parameters of the sound and consequently the resulting annoyance caused the amplitude changes in both the alpha and beta bands. So, it can be concluded that the psychoacoustic annoyance is a good indicator of brain activity.