By Lawrence Solomon
A Canadian court will soon decide if wind turbines violate Canada’s Charter of Rights and Freedoms by posing a risk to human health. Charter case decisions can be convoluted but the fundamental question of health at issue here is straightforward. Wind turbines, from all that is today known and by any rational measure, represent a risk to those living in their vicinity.
Although the wind industry and its government backers tend to dismiss concerns, the evidence of harm in communities that host wind turbines is overwhelming. Literally thousands of people around the world report similar adverse health effects, some so serious that owners abandon their homes. Studies of noise from turbines — though few in number, short in duration, tentative in their findings and conducted by interested parties — point to dangers. As if these weren’t enough, basic science sounds the alarm on wind turbines.
Wind turbines produce audible sound waves known to cause what medical science calls “annoyance,” a state of health that can lead to a constellation of illnesses called wind turbine syndrome (WTS). As Health Canada reported earlier this month, following a Statistics Canada survey it commissioned of people living in the vicinity of wind turbines, “[wind turbine noise] annoyance was found to be statistically related to several self-reported health effects including, but not limited to, blood pressure, migraines, tinnitus [ringing in the ears], dizziness” and sleep disorders. The annoyance was also found to be statistically associated with objective measurements of chronic stress and blood pressure. Health Canada’s bottom line: “the findings support a potential link between long-term high annoyance and health.”
The audible sound waves — these have a frequency above 20 Hz — may be the least of the worries faced by those living near wind turbines. The turbines also produce copious amounts of sound waves below 20 Hz, making them inaudible to the human ear and thus, say wind proponents, harmless. Yet sound at this low frequency, known as infrasound, should not be thought of as faint or weak. The U.S. military has studied the use of infrasound in non-lethal weapons. Many mammals — giraffes, elephants, whales — communicate with each other at infrasound frequencies, even when many kilometres apart. Powerful infrasound waves, in fact, explain how animals sense the coming of earthquakes well before humans do — and why animals fled to safety during the calamitous Sumatran and Japanese tsunamis of recent years.
Like other mammals, humans are sensitive to infrasound, even though the human ear doesn’t “hear” it. Our inner ear has four rows of hair cells, only one of which — the fourth row — “hears.” It does this by converting sound-wave energy above 20 Hz to electricity that then travels to the brain, which makes the sounds intelligible to us. The first three rows of hair cells also convert sound, this time for sound-wave energy below 20 Hz. The electric signals from this infrasound also enter the brain but the current state of science doesn’t know much of what happens next. It especially doesn’t know what happens when the brain receives infrasound stimulation for prolonged periods, let alone 24/7 as happens with people living near wind turbines, because no long-term study has ever been conducted to find out, either on animals or on humans.
Numerous short-term studies in both animals and humans do exist — a 2001 review by the U.S. National Institute of Environmental Health Sciences, the Infrasound Toxicological Summary, located more than 100 infrasound studies around the world, many of the subjects in the human studies reporting the same adverse health effects — fatigue, sleeplessness, nausea, heart disorders — that afflict those living near wind turbines. In an unusual 2003 U.K. experiment involving the National Physical Laboratory, the country’s largest applied physics organization, back-to-back music concerts were staged in London’s Purcell Hall, similar in all respects except that two different musical pieces in each concert were laced with infrasound. The result: while hearing the infrasound-laced pieces, audience members reported significantly elevated sensations of nausea, dizziness, increased heart rates, and tingling in the neck and shoulders, among other sensations.
It’s clear from the documents that come out of the wind industry that they’re trying very hard to suppress the notion of wind turbine syndrome”
Despite the well-document effects of infrasound on animals and humans, the vast majority of studies of sound from wind turbines ignore the effects of infrasound; they instead compare wind turbine sounds to audible sounds coming from benign appliances such as refrigerators, say Alec Salt and Jeffery Lichtenhan of Washington University’s School of Medicine, authorities in the field of acoustics. The failure to take infrasound seriously, they state, is “quite astounding … Given the knowledge that the ear responds to low frequency sounds and infrasound, we knew that comparisons with benign sources were invalid and the logic [of relying on audible] sound measurements was deeply flawed scientifically.”
Salt and Lichtenhan have documented the many ways that wind turbine noise can affect the ear, concluding that it is “highly unlikely” that wind turbines don’t present a danger. “Given the present evidence, it seems risky at best to continue the current gamble that infrasound stimulation of the ear stays confined to the ear and has no other effects on the body.”
Their view, and that of other experts in the acoustics field such as Harvard Medical School’s Steven D. Rauch, is that, in the absence of other explanations, it is preposterous to dismiss wind turbines as a cause of wind turbine syndrome (WTS).
“The patients deserve the benefit of the doubt,” says Rauch, who believes that wind turbine syndrome is real. “It’s clear from the documents that come out of the industry that they’re trying very hard to suppress the notion of WTS and they’ve done it in a way that [involves] a lot of blaming the victim.”
Salt, Lichtenhan and Rauch may one day be proven wrong, and wind turbines may be found to be benign. Or wind turbine technology may change, to mitigate or altogether avoid any harmful production of sounds. Until that day comes, the risks from wind turbines are palpable, even if not always audible.