Exposure to Infrasound and Low Frequency Noise—A Case Study of Guarda City Population (Portugal)

Wind energy plays an unavoidable role in the Portuguese electricity sector. Despite the several environmental advantages associated to this infrastructures and technological advances to make wind turbines quieter, they still produce sounds resulting from their mechanics and aerodynamics, in particular infrasound and low frequency noise. The aim of this study was to access the levels of infrasound and low frequency noise that the Guarda city population was exposed to. A total of 134 measurements were carried out in 67 points of urban areas. CESVA SC420 sound level meter (with “FFT Analysis” module) was used. Based on the measurements taken, infrasound and low frequency noise were calculated. The statistical analysis of the results was carried out using the IBM SPSS software. Statistically significant differences were found between the northern and north-western zones of the city compared to the western zone, regarding infrasound and infrasound exposure and low frequency noise. Regarding the low frequency noise there were no statistically significant differences between the various areas of the city. It was also possible to see that with the increase of air speed, there was also an increase in sound pressure levels. It was possible to conclude that the infrasound results are higher than the low frequency noise results. Although the infrasound frequency is below the audible threshold, it can bring problems to human health.