## 4 Discussion
Additionally, a study by [81] also justifies its potential theta-to-alpha ratio as an indicator of workload. This is based on the assumption that an increase in theta strength bands and a decrease in alpha strength in the frontal brain region are associated with an increase in mental workload [82]. Exposure to significant noise can increase the mental workload of individuals. Mental workload increases with increasing noise levels, and the results are linear in a study by [35]. An EEG analysis of the brain signals revealed the presence of noise in the beta and alpha frequency bands. The relative intensities of the alpha and beta bands increase and decrease, respectively, as noise levels grow [16]. In this case, it may be said that when noise levels increase, attention rates fall even while the relative intensities of the alpha and beta bands increase and decrease. Based on the results of EEG topography mapping as a spatial representation of brain electrical activity measured from various electrodes placed on the scalp in Figure 9a,b, there is a change in signal strength at each noise level in the continuous noise type (Figure 9a) and the intermittent noise type (Figure 9b). The topography results at all noise levels and noise types display that all active electrodes take turns giving signals. The topographic color map shows the intensity of brain activation [83]. The topography color map of the EEG for the alpha band shows where red represents the maximum value and blue represents the minimum value [84]. Previous studies also stated that beta wave activity is closely related to the level of attention, where the redder the map color on the topography, the higher the level of attentional energy produced [85; 86]. A reduction in the relative strength of the beta band as a result of increased noise levels occurred in the frontal, temporal, occipital, and central lobes in the topographic map results of [16]. There were conflicting results regarding the effect of noise on cognitive function in previous studies. Some studies determined that noise had improved cognitive function [87]. While a study concluded that noise had reduced cognitive function [88], previous findings revealed that decreased cognitive function and brain signals were only significant when exposed to noise at 95 dB and not at 75 or 85 dB [16]. Previous study findings stated that intermittent noise had a greater detrimental effect on performance compared to continuous noise [89]. The findings of this study explained that continuous noise had a different impact than intermittent noise on cognitive ability. The difference lies in the individual characteristics, as when individuals face noise, personal characteristics may be important because some individuals may experience decreased cognitive performance while others may not, and some may even show symptoms of increased cognitive performance [90]. The study conducted by [16; 91] indicated that the complexity of brain activities increased at moderate frequencies and showed the influence of frequency changes on brain activity. The brain signal analysis indicated that frequency bands such as alpha and beta were affected by noise. With increasing sound pressure levels, the relative power of alpha increased and beta decreased. While various parts of the brain applied complex activities during analysis and confrontation with noise, measuring changes in the temporal lobe was effective in evaluating stress [12]. Alpha and beta bands were correlated with attention, stress levels, and fast brain activities such as decision-making, analysis, and data processing in the frontal lobes. An increase in alpha indicated that subjects felt more relaxed after exposure to noise, after which a decrease in alpha indicated that the tension or relaxation they felt decreased [92; 93]. The results of this study are expected to provide recommendations for the development of environmental policies regulating noise levels in various contexts, including workplaces, schools, and urban areas.