A Review of the Possible Perceptual and Physiological Effects of Wind Turbine Noise

Abstract

This review considers the nature of the sound generated by wind turbines focusing on the low-frequency sound (LF) and infrasound (IS) to understand the usefulness of the sound measures where people work and sleep. A second focus concerns the evidence for mechanisms of physiological transduction of LF/IS or the evidence for somatic effects of LF/IS. While the current evidence does not conclusively demonstrate transduction, it does present a strong prima facia case. There are substantial outstanding questions relating to the measurement and propagation of LF and IS and its encoding by the central nervous system relevant to possible perceptual and physiological effects. A range of possible research areas are identified.

A Review of the Potential Impacts of Wind Turbine Noise in the Australian Context

“…In a further publication, the committee [12] recognised and responded to the need to review the scientific literature relating to possible perceptual and physiological effects of infrasound and low-frequency sound (IS/LF). Previous reviews [13][14][15][16][17][18][19][20][21] have mostly relied on an epidemiological approach providing meta-analysis of the existing populationbased research.…”

“…Studies of the generation and propagation of IS/LF sound by wind turbines demonstrate that the acoustical energy per unit frequency at the blade-passing frequency (BPF) and at its harmonic frequencies below 10-15 Hz is greater than at higher frequencies. Propagation models and field studies have indicated that sound at these IS/LF frequencies can propagate with less attenuation with distance than higher frequencies because of their lower sound absorption during passage through the air and on reflection from the ground [12,[22][23][24][25][26][27][28]. Added to this is uncertainty regarding the effectiveness of sound insulation of houses at infrasound and low frequencies [29].…”

“…Reviews of physiological transduction and neural excitation provided a strong prima facia case for the transduction of IS/LF [12,30,31] and stimulation of the human nervous system consistent with studies demonstrating perceptual sensitivity to high levels of IS/LF sounds and to neural (cortical) activation at more moderate sound levels [12,[32][33][34]. While these data do not by themselves, speak to the health effects or not of wind turbine noise (WTN), they do demonstrate that such sounds are encoded by the human nervous system.…”

“…This leads some researchers to believe that wind turbine noise below 50 Hz is not a problem [50][51][52][53]. However, as noted in the committee's previously published analysis [12], not all researchers agree that this is the case [25,30,31,54].…”

“…Hence some caution is needed, but the current IoA amplitude modulation rating method is the best candidate for trial in Australia. It should be noted that none of the AM rating systems so far proposed include the possible effect of basilar membrane biasing by the blade-passing tone and its harmonics [12]. Hansen et al [81] have shown that the IoA method may need to be modified in some circumstances, particularly when the amplitude modulation is of a tone below 50 Hz.…”