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Documents > Noise, health > Infrasound and Low Frequency Noise - Part 2: Infrasound felt up to 40 km

Infrasound and Low Frequency Noise
Part two: Infrasound felt up to 40 km

Just as Dr Sarah Laurie is under attack from a furiously pro-windfarm Australian professor, and EPAW from a French "windy" journalist who claims he "slept like a baby" 200 meters upwind from a wind turbine — the silent side, you guessed it — news keep coming which prove we haven't been told the truth about wind turbines.

In "Part one", you have seen that the wind lobby itself acknowledges that wind turbines produce infrasound - see nº2 "Pulsing sounds": what is sensed inside homes as "vibrations and pulsing changes" is in fact infrasound, which is only perceived by the inner ear and other internal organs. If not, it would be felt as audible sound by the outer ear. It must be noted that, for the majority of people, the outer ear does not perceive sounds whose "frequency" is below 20 Hz – these are thus called "infrasound".

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French scientist Vladimir Gavreau finds his laboratory flooded with a mysterious energy (infrasound) that has debilitating effects on the human body. (Science Channel video)

In the letter and memoir we publish below, we are told that some frequencies below 20 Hz (say, 16 Hz) can be perceived as audible sound by about 6% of men and 18% of women, up to distances of 40 km in certain atmospheric conditions (a stable layer of air next to the ground). As a result, the lady in question in the memoir must switch the radio on in order to be able to sleep.

Note: the fact that 94% of men and 82% of women cannot hear certain very low frequencies that others can, doesn't mean that their inner ears do not perceive them, nor that their internal organs do not resonate at those frequencies. In fact, their bodies sense them as vibrations and pressure changes. What is more, this infrasound can cause harm. In fact, it can even kill, as we shall see in Part 3.

The longer their exposure to infrasound (0,1 Hz to 20 Hz) or to audible low frequency noise (20 Hz to 200 Hz), the higher the health risk for neighbours. For instance, it is universally recognized that chronic lack of sleep weakens the body's defenses, or that stress is a factor in cardiac arrests. And it is a fact that low or very low frequencies can cause insomnia, headaches, poor concentration, tinnitus, nausea, stress, high blood pressure, cardiac arrests, depressions, suicides, etc. The effects are amplified at night, when wind is generally stronger and the countryside silent. An added factor is the pulsating nature of the sound emitted, which is caused by the blades as they pass in front of the tower, or because of the difference in wind speed at the top and at the bottom of the tower (this is the latest explanation given). These pulsations, which are akin to a heart beat but without quite matching it, have a stressing effect, especially during sleep.

Infrasound is dangerous, as demonstrated in the 1960s by French scientist Vladimir Gavreau (video above and footnote 1). His studies were developed further by the military in several countries, but it is difficult to turn infrasound into a weapon that discriminates between friends and foes. However, a crowd control device using infrasound has been presented last year by Raytheon (2).

It is also interesting to note that another study, published in Scotland in 2005, concludes that seismic vibrations from wind turbines can be felt as far as 50 km (3).

(1) -

(2) -

(3) - see page 90:
"4. Beyond 50 km, we do not anticipate that ANY reasonable windfarm development will have an impact on the detection capabilities of Eskdalemuir" (it's a detection center for nuclear explosions around the world, located in Scotland).

Here is now the letter to the New Scientist, about infrasound impacting some people 40 km away from a windfarm. Don't miss the memoir that follows, which is very well made and most interesting.

Unexplained Low Frequency Noise

Note: Technical papers distinguish infrasound (below 20 Hz) from low frequency noise (20-200 Hz), since 20 Hz is the lowest sound frequency considered by "experts" to be audible to humans.

I have used the term Low Frequency Noise (LFN) in this document to refer to all sound frequencies below 200 Hz since I do not know what spectrum of low sound frequencies my wife is capable of hearing.

Dear New Scientist,

I couldn't believe the biased rubbish written in the article by Prof Simon Chapman in New Scientist on 08 Oct 2012. It is obvious he doesn't live near a wind farm. I firmly believe that increased health problems will proliferate as wind farms continue to multiply and more people are subjected to regular exposure to LFN and infrasound.

I have personally met a person living near a wind farm who became mysteriously ill and eventually lost her job. 2 years later, after reading a



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