Wind turbine infrasound: Phenomenology and effect on people

Abstract

• The extraordinary behaviour of infrasound waves is explained phenomenologically. • Wind turbine infrasound produces perceptible vibrations and audible sound in nearby buildings. • Most people are unaffected by wind turbine infrasound, but some people have a phobic reaction to it. • Bracing the diaphragm structures in the dwellings of affected people may solve the problem. With the expansion of green energy generation, infrasound from wind turbines will increase and it is important to understand and ameliorate its adverse effects on people. This research reviews the phenomenological behaviour of infrasound and its interaction with structures and provides an explanation for the contradictory findings on the effect of wind turbine infrasound on nearby residents. Infrasound has very long wavelengths, a planar wave structure and is outside the range of normal hearing for moderate sound pressure levels. The attenuation of infrasound is complex; it initially increases with distance from the source (becoming quieter), but it can decrease over still further distances so that it then gets louder. When it interacts with buildings, it can produce secondary structural vibrations that may be perceptible to the occupants. Infrasound from wind turbines is particularly annoying because the sound signature contains short, frequent episodes and it persists over extended periods, compared with other short-duration sources (such as trains). Most people can ‘tune out’ repeated sounds but in some people the central nervous system becomes sensitized and they suffer the symptoms of chronic noise stress such as anxiety, depression, cognitive dysfunction and disrupted sleep. Bracing the diaphragm structures in dwellings may offer remediation.

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