EK 130 Wind

One of the most prevalent concerns regarding the possibility of wind turbines’ effect on human health is the phenomenon of infrasound. Though infrasound is by no means a unique product of turbines but rather a product of all machinery and natural forces such as the wind or ocean, the propagation of wind turbines has been associated with symptoms in proximate people which are debatably identified as the result of infrasound. Across the human range of hearing, the frequencies of roughly 20-20,000 Hz are typically heard at any volume. Infrasound, which is described as sound with frequency roughly less than 20 Hz, is too low for humans to feel unless its volume reaches high levels- 60-100 dB, somewhere between the volume of a coffee grinder to a moving truck (2). But though infrasound cannot usually be heard, an exceeding amount of data suggests that what you cannot hear can hurt you. At the same time, however, there are effective counterarguments which may just as easily disprove infrasound as a legitimate threat to human health. Because it seems equally likely that the discomfort and pain experienced by many in the vicinity of turbines is caused by infrasound as it is that they are psychosomatic, more research needs to be done on how infrasound affects humans before either perspective is embraced.

Though infrasound cannot be heard, it still exists and can affect people for what sound really is- vibration. Thus, though otherwise silent, infrasound is capable of moving internal organs to some degree, thus instigating nausea, and high volumes regardless of frequency can stimulate the fight-or-flight reaction, increasing heart rate and blood pressure (East Coast Research and Investigation of the Paranormal). Additionally, because lower-frequency air pressure pulses lose much less energy than higher frequencies of sound, infrasound is capable of causing walls to resonate thus entering houses which are insulated against audible noise. Because infrasound is usually masked by higher frequencies of sound, it is therefore possible for people to have relatively more exposure to infrasound while indoors (4).

There exists a plethora of studies which account for the symptoms observed. Robert Rand, a member of the Institute of Noise Control Engineering (INCE) and a technician with 30 years of experience, stumbled upon symptoms of the infamous “Wind Turbine Syndrome” himself. Having been asked to investigate the potential danger of wind turbines on a site in Maine, Rand and a colleague from the INCE both experienced “nausea, loss of appetite, headache, vertigo, dizziness, inability to concentrate, an overwhelming desire to get outside, and anxiety” upon entering a building near the turbine (1). Another example would be a survey conducted by Zhenhua Wang, a graduate student in Geography, Environment, and Population at the University of Adelaide, Australia.  The survey asked civilians living within 5 km of a wind farm whether or not they were negatively affected by the noise, and it yielded that 70% of them were, 50% being “very or moderately negatively affected.” Only 35% of the surveyers were actually opposed to wind energy, dissuading the possibility of psychosomatic influence (6). Furthermore, in line with the hypothesis that excessive infrasound can cause discomfort through the vibration of internal organs, people who have had wind turbines installed near their homes have reported a variety of symptoms which did not exist before the turbines’ installation. They feel internal pressure and have heart issues- as the average heartbeat is less than 1.25 Hz, a frequency within the range of infrasound itself, pervasive vibrations from excessive infrasound may be the cause (4).

Yet, there exist several convincing counterarguments as well. First, research shows that wind turbines are not quite as loud as some people believe. A widely accredited study in Denmark by Moller and Pederson revealed that houses beyond 1414 m, or 4600 ft, from 3 MW turbines receive 35 dB of sound. As the hearing/perception threshold for infrasound is about 70 dB, and because decibels work on a logarithmic scale, this means that houses a reasonable distance away from turbines do not receive levels of infrasound remotely close to levels at which they are believed to be felt (7). Also, prevalent symptoms thought to be caused by wind turbines, especially in Australia, are in fact naturally occurring. Roughly 29% of Australian adults have hypertension, though half of them are aware of it. Similarly, around 5% of Australian adults have insomnia- so, when they are diagnosed for the first time, civilians suffering from hypertension or insomnia will not attribute it to natural causes and will instead assume that it is the result of nearby wind turbines’ “notorious infrasound.” Similarly, the fear and panic spread by many anti-wind activists is likely to cause a “nocebo” effect, which is conjugate to the placebo effect- after being told to expect to acquire disease or symptoms, people will develop them. Perhaps most concerning about the argument that wind power’s infrasonic influence is detrimental to human health is the fallacious and misleading citations by its most well-known activists. Sarah Laurie, who never received a doctorate, is one such icon of the anti-wind movement. In one document, Laurie cited evidence that infrasound produced harmful effects in humans, and thus wind turbines were easily responsible for a multitude of symptoms. What she failed to mention is that the evidence applied to infrasound at extremely high volume- 125 dB or more- and that wind farms will emit at most about 65 dB in their direct vicinity and less over a distance. Nina Pierpont, the New York Pediatrician who coined the term “Wind Turbine Syndrome,” misquotes a study by Todd et al published in the journal Neuroscience Letters as a foundational support in her argument- “The very low [noise] thresholds we found ar remarkable as they suggest that humans possess a frog- or fish-like sensory mechanism which appears to exceed the cochlea for detection of substrate-borne low-frequency vibration and which until now has not been properly recognised.” The actual study does not pertain to “noise,” which Nina Pierpont inserts, but rather substrate-borne vibration, and though the author has publicly responded to this quotation with the statement that his research shows no evidence that hypothesized acoustico-physiological mechanisms are caused by the sound of turbines, she continues to misuse the quotation (9). If the scientists arguing for the harmful effects of infrasound are not credible, so too is their argument.

Currently, there is not enough research on the effects of infrasound on humans to classify turbines as harmful or harmless. Studies by scientists such as K Persson Waye of Alborg University, Denmark, conclude that “present studies are not conclusive with regard to objectively measured effects,” because mechanisms and models need to be developed to control varying factors in infrasound exposure (5). This must be dealt with- even the Department of Environmental Protection does not test for infrasound when deeming institutions safe because their policy is not defined to cover anything but audible sound (3). Once this policy is changed, and proper research is conducted, the nature of wind turbines will actually become clear- the truth must be found before any action can be taken.

Works Cited

1. Lloyd, Graham. The Australian. “What you can’t hear can hurt you.” January 25, 2012. Retrieved November 29, 2012. http://www.theaustralian.com.au/news/features/what-you-cant-hear-can-hurt-you/story-e6frg6z6-1226252801681
2. Author unknown. East Coast Research and Investigation of the Paranormal. “Infrasound.” Date unknown. Retrieved November 28, 2012. http://www.eastcoastrip.org/did-you-know/infrasound
3. Wittenberg, Ariel. South Coast Today. “Infrasound remains controversial, mysterious.” July 1, 2012. Retrieved November 29, 2012. http://www.southcoasttoday.com/apps/pbcs.dll/article?AID=/20120701/NEWS/207010342
4. Post, Willem. The Energy Collective. “On Wind Turbine Noise and Air Pressure Pulses.” May 7, 2012. Retrieved November 27, 2012. http://theenergycollective.com/willem-post/84293/wind-turbine-noise-and-air-pressure-pulses
5. Waye, K Persson. Noise & Health. “Effects of Low Frequency Noise on Sleep.” 2004. Retrieved November 29, 2012. http://www.noiseandhealth.org/article.asp?issn=1463-1741;year=2004;volume=6;issue=23;spage=87;epage=91;aulast=Waye
6. Zhenhua, Wang. National Wind Watch. “Evaluation of Wind Farm Noise Policies in South Australia: a Case Study of Waterloo Wind Farm.” February 29, 2012. Retrieved November 29, 2012. http://www.wind-watch.org/documents/evaluation-of-wind-farm-noise-policies-in-south-australia/
7. Author unknown. The Acoustic Ecology Institute. “Recent research on low frequency noise from wind turbines.” December 31, 2011. Retrieved November 27, 2012. http://aeinews.org/archives/1711
8. Author Unknown. Bavarian State Office for Environment, Bavarian State Office for Health and Food Safety. “Windkraftanlagen – Beeinträchtigt Infraschall die Gesundheit?” Date unknown. Retrieved November 27, 2012. http://www.lfu.bayern.de/umweltwissen/doc/uw_117_windkraftanlagen_infraschall_gesundheit.pdf
9. Chapman, Simon. Reason Australia. “Is ‘Wind Turbine Syndrome’ Mass Hysteria?” Date unknown. Retrieved November 29, 2012. http://www.reasonaustralia.org/news/articles/216-is-wind-turbine-syndrome-mass-hysteria