Infrasound and The Body
The rapidly spinning blades of huge wind turbines have an effect on their surroundings, and it goes beyond aesthetics. The blade tips of a wind turbine can spin at speeds of up to 80 meters per second, or about 180 miles per hour. In high winds, this rapid spinning can produce sound and vibration -- in addition to disruptions in air pressure [source: MIT].
The extremely low air pressure surrounding a wind turbine could be the reason why bats die near them. A bat's lungs are very delicate, and it seems the low pressure might cause them to expand to the point of bursting blood vessels [source: NewScientist]. Scuba divers can certainly attest to the effects of pressure on the human body. And the corporeal effects of sound -- essentially fluctuations in air pressure that vibrate the eardrum -- are well-documented. For instance, infrasound -- sounds at such low frequency that they can't be picked up by the human ear but can carry through the atmosphere for thousands of kilometers -- is believed to cause certain breathing and digestive problems [source: Infrasound Lab].
Infrasound is the primary issue for those concerned about wind-turbine syndrome. They also say that audible sound and vibrations contribute to the health problems reported by some people who live close to wind farms. Symptoms of wind-turbine syndrome might include:
- sleep problems
- night terrors or learning disabilities in children
- ringing in the ears (tinnitus)
- mood problems (irritability, anxiety)
- concentration and memory problems
- issues with equilibrium, dizziness and nausea
These symptoms have been observed and documented by a limited number of scientists studying small groups of people, and the scientific community hasn't concluded whether wind-turbine syndrome exists. There are also mixed opinions on whether wind turbines emit infrasound and if the amount is any more than that emitted by diesel engines or waves crashing on the beach [source: CleanTechnica, ABC Science]. But we do know that at high speeds, wind turbines can produce an audible hum and vibration that can be carried through the air.
It's these sounds and motions that provide clues and possible solutions to wind-turbine syndrome, which we'll explore in the next section.