This article, the final of three installments, discusses the relationship between various health effects and our current understanding of the processing of infrasound by the ear and brain. [Part 1: Some Background; Part 2: The Evidence.]
As noted in the second installment of this series, Dr. Geoff Leventhall, a co-author of the 2009 AWEA/CanWEA report, attributes the health complaints of people who live near industrial wind turbines (IWTs) to psychological stress, but does not acknowledge that IWTs can be detrimental to health because infrasound and low-frequency noise (ILFN) emitted by wind turbines are largely inaudible to humans. He stands on the argument, therefore, that what we can’t hear can’t hurt us.
We know that things we cannot see, touch, taste, or smell can hurtus, so why is it unreasonable also to believe that what we can’t hear might also hurt us?
Dr. Nina Pierpont, in describing Wind Turbine Syndrome (WTS), has expressed her belief that many of the symptoms comprising WTS are mediated by overstimulation of the vestibular system of the inner ear by ILFN. Recent evidence supports the general view that the functioning of both the vestibular and cochlear components of the inner ear, and their interconnections with the brain, mediate the type of symptoms that Pierpont and others have described.
INFRASOUND: MORE OF A PROBLEM THAN WE THOUGHT?
Industrial-scale wind turbines generate peak sound pressure levels at infrasonic frequencies, especially between 0.25 and 3 Hz, as the blades pass in front of the tower. Most of us do not experience the energy in this lowest of low-frequency regions as sound; instead, we perceive a variety of other sensations. When present, infrasound can be more of a problem than audible sound.
Recent basic research on the inner ear conducted by Dr. Alec Salt and colleagues at the Washington University School of Medicine in St. Louis has provided a feasible and coherent explanation of how sound that is normally not audible can result in the kinds of negative reactions reported by people who are exposed to wind turbine noise. That research has shown that extremely low-frequency sound is largely inaudible to humans because the outer hair cells (OHCs) in the inner ear detect and effectively cancel it before it reaches the inner hair cells (IHCs). The IHC stereocilia, which do not contact the tectorial membrane, are fluid-coupled and sensitive to stimulus velocity, while the OHC stereocilia are sensitive to displacement. IHCs rapidly become less sensitive as stimulus frequency is lowered.
Readers familiar with the anatomy of the ear know that approximately 95% of the fibers innervating the IHCs lead to the brain as afferent fibers, while only about 5% of the fibers innervating the OHCs are afferent fibers. Thus, we hear through our IHCs, and our hearing sensitivity is comparable to the calculated IHC sensitivity. The OHCs, which respond physiologically to infrasound, serve as a pathway for infrasound to reach the brain. Infrasonic signals that reach the brain are normally not perceived as sound, but are believed to stimulate centers other than auditory centers, resulting in perceptions that may be unfamiliar and disturbing.
Similar pathways to various centers of the brain also exist through the vestibular, or balance, mechanisms of the inner ear, meaning that it is biologically plausible for infrasound to produce the variety of sensations described by Pierpont, sensations such as pulsation, annoyance, stress, panic, ear pressure or fullness, unsteadiness, vertigo, nausea, tinnitus, general discomfort, memory loss, and disturbed sleep.
Salt and colleagues have also found that when higher-pitched sounds (150-1500 Hz) are present, they can suppress infrasound. This means that the ear is most sensitive to infrasound when higher-frequency sounds are absent. This occurs at night when wind turbine noise is present, ambient sound levels are low, and higher-pitched sounds are attenuated by walls and other physical structures.
Another relatively recent discovery is that there is likely a cause-effect relationship between AHEs and ILFN that mirrors that occurring in motion sickness. An experiment in the late 1980s, conducted using training-mission scenarios with Navy pilots, showed that motion sickness was associated with significant amounts of acoustic energy inside the flight cabin over the frequency range from just under 1 Hz to as low as 0.05 Hz (the nauseogenic range). Maximum sensitivity occurred at approximately 0.2 Hz. That experiment resulted in the conclusion that flight simulator sickness may be, to a significant extent, a function of exposure to infrasonic frequencies. This phenomenon is akin to seasickness, except that the acoustic energy causes nausea without body movement or visual stimulation.
Dr. Paul Schomer, nationally and internationally known for his work in acoustics and acoustic-standards development, has suggested that because the Navy test subjects responded to acoustical/vibratory energy with symptoms similar to motion sickness, many of the similar symptoms reported by people living near IWTs can be explained by exposure to infrasound from wind turbines at frequencies similar to those observed in the Navy’s test environment. Persons affected by wind turbine noise appear to be responding directly to acoustic stimulation of the same nerves and organs affected in that experimental environment.
DATA SUPPORT REPORTED SYMPTOMS AS BIOLOGICALLY PLAUSIBLE
These research efforts of Salt and colleagues, Schomer, and others are leading the way in establishing the biological plausibility of the harmful effects of ILFN generated by wind turbines.
Dr. Salt dismisses the common perception that what we can’t hear can’t hurt us and has stated unequivocally that “Wind turbines can be hazardous to human health.”
Decisions regarding the siting of industrial wind turbines deserve careful attention to limiting noise exposure levels in community residents through specified restrictions on either distance or noise levels, or both. The right of the public to enjoy health and well-being should be paramount to the economic and political interests of the wind industry and governmental bodies. These rights need to be protected on a proactive, and not just on a retroactive, basis. Industrial-scale wind turbines should be sited only at distances from residents that are sufficient to minimize sleep disturbance and that do not put them at risk for a variety of other serious health problems.
Jerry Punch is an audiologist and professor emeritus at Michigan State University in the Department of Communicative Sciences and Disorders. Since his retirement in 2011, he has become actively involved as a private audiological consultant in areas related to his long-standing interest in community noise.
Richard James is an acoustical consultant with over 40 years of experience in industrial noise measurement and control. He served as an adjunct instructor in Michigan State University’s Department of Communicative Sciences and Disorders from 1985-2013 and currently serves as an adjunct professor in Central Michigan University’s Department of Communication Disorders.
[Originally published at Hearing Health & Technology Matters, Nov. 18, 2014]
The right to be free from chronic annoyance is at the heart of a legal challenge that could shake Ontario’s multibillion wind-energy business, and limit other industrial development in rural areas.
It pits a family whose farming history goes back a century in Southwestern Ontario against the provincial government, and a consortium known as the K2 Wind Power Project, which includes global companies such as Samsung Renewable Energy Inc.
No evidence shows wind turbines directly harm human health.
But “community annoyance” lasting a year or more and associated with nearby turbines has been linked to headaches, sleep problems, dizziness and high blood pressure, in a study whose summary was released by Health Canada early this month. Continue reading Legal battle over Ontario wind turbine farm may redefine ‘harm’
The Canadian Press – Shawn Drennan, part of a four-family fight against Ontario’s wind-turbine legislation, is seen outside court in London, Ont., on Monday, Nov. 17, 2014. THE CANADIAN PRESS/Colin PerkelWind turbines are like new neighbours who might drive you to distraction and out of your home because you have no legal way to deal with the situation, a packed Ontario court heard Monday.
In submissions to Divisional Court, a lawyer for four families fighting large-scale wind-energy projects compared the turbines to a neighbour who is always noisy and in your face.
“This neighbour never once ruptured your eardrums but that neighbour slowly drives you crazy,” Julian Falconer told the court.
“These turbines are those nightmare neighbours.”
The families are trying to get the court to declare provincial legislation related to the approvals of large-scale wind farms unconstitutional.
In essence, they argue, the legislation makes it impossible to scuttle a project on the basis of potential health impacts.
“The priority is to get the turbines up come hell or high water and that’s what they do,” Falconer said.
Governments love windmills, people who live near them hate them. The result is a beautiful recipe for lawyers.
Mr. Falconer is one of the country’s top constitutional and human rights lawyers. He represented the Smith family in a lawsuit into the death of Ashley Smith in custody. He worked on the Ipperwash Inquiry. He represented Maher Arar in a suit against the federal government over his rendition and torture in Syria. The list goes on. Point is, Mr. Falconer takes a special interest in holding government to account.
On Monday he’ll be taking on windmills. He wants Ontario’s Divisional Court to overturn the regulatory approvals of three projects, the St. Columban Wind and K2 Wind Energy project in Huron County, and the SP Armow Wind project near Kincardine, Ont.
His clients, who live near the projects, fear the noise and vibration of the wind turbines will trigger a host of serious health problems. Mr. Falconer will argue in court that Ontario’s process for approving wind farms violates the Charter of Rights and Freedoms. Provincial legislation says anyone challenging a wind farm project before Ontario’s Environmental Review Tribunal must prove “serious harm” to human health. Mr. Falconer says that threshold is unfair because it is too high.
“The effects of wind turbines are felt in the most private and personal areas of residents’ lives, in their homes and beds, where the state has its lowest interest in intrusion,” Mr. Falconer submits in his written argument.
The Charter argument is a fairly new wrinkle in the fight against wind farms. But litigation itself isn’t. When the Divisional Court rules on the appeal, its decision will join the more than 30 Canadian reported court cases that have dealt with wind turbines — a number that shoots to nearly 100 when you include hearings before Canadian regulatory tribunals.
Health Canada’s Wind Turbine Noise and Health Study: Summary of Results 1
Summary Statements  regarding the above study were released this past week by Health Canada; however, the study itself was not released.
Health Canada’s summary report on wind turbine noise and health confusing
Media timing issues relating to summary report release and issues with CANWEA press release
Some summary statements indicate no association between wind turbine noise and health
Some summary statements appear to indicate an association between wind turbine noise and health
Reports immediately following Health Canada’s press advisory state no problems with wind turbines
No peer reviewed study results released – caution advised in interpretation of summary statements
Summary report statements appear “rushed” given no study or peer reviewed study available
Children, Noise, Annoyance, Respiratory Effects, World Health Organization
MAWT Inc. would like to go on record and say that we have read and support the Denise Wolfe/Dr. McMurtry critiques of the Health Canada study as well as Carmen Krogh’s.
Following Canada’s Wind Technology Roadmap and Health Canada’s Wind Turbine Noise and Health Study Carmen Krogh,BScPharm Brett Horner, BA CMA