While audible noise from wind turbines is known to disturb sleep, be extremely annoying, and substantially reduce quality of life, health symptoms such as headaches, dizziness, nausea, and motion sickness seem to be explained best by exposure to infrasound. Paller et al.,5 in Canada, found a statistically significant association between wind turbine noise and vertigo, although few studies have established a direct causative relationship. Schomer and colleagues6 have explained that the types of vestibular symptoms reported by individuals living near wind turbines, including vertigo, are similar to motion sickness, which is known to be induced by very low-frequency sources below 1 Hz—which modern wind turbines are known to produce. Their study indicates that the vestibular components of the inner ear appear to be central to motion sickness and other balance disorders reported by persons living near wind turbines. Dr. Nina Pierpont7 has explicitly described the relationship between complaints associated with wind turbine noise exposure and migraines, motion sickness, vertigo, gastrointestinal sensitivity to noise and visual stimulation, and anxiety. Despite the wind industry’s vigorous denials, recent research is largely consistent with Dr. Nina Pierpont’s original description of symptoms resulting from exposure to wind turbines, which she termed Wind Turbine Syndrome.
Wind turbine noise has unique acoustic characteristics when compared to other environmental noises. Those characteristics include amplitude modulation with intermittent occurrences of tones that mirror the peak energy of the blade-pass frequency and the first several harmonics. Infrasound emissions from wind turbines can also resonate air inside closed rooms, effectively amplifying any acoustic energy that is present, and can resonate, or vibrate, organs and tissues of the human body.8 The wind industry often states that infrasound from turbines is less intense than infrasound generated by other environmental sources or within the human body itself. Based on its anatomical characteristics, however, the inner earis capable of preventing internally generated sound, but not externally generated sound, from being perceived, which means that perception of wind turbine infrasound may be far more disturbing than any infrasound generated within the body. Also, infrasound is more perceptible when higher frequencies are absent, meaning that conditions are likely to be at their worst in a quiet bedroom at night, when higher frequencies are relatively attenuated by the surrounding structures of a residence.