Thursday, 21 November 2013

Wind turbines are quieter than a heartheat, acoustical experts find
24 Sep 2013

One complaint voiced by wind turbine opponents is that the turbines create too much noise--even noise below the range of human hearing, known as infrasound. These concerns fuel claims about "Wind Turbine Syndrome", which advocates say is a medical condition that involves mental health problems, heart disease, and vertigo.

A study by an acoustic engineering group in Australia found that that infrasound generated by wind turbines is less loud than the infrasound created by a listener's own heartheat. It found that wind turbine infrasound does increase as wind speed increases, but this is often masked by the natural noise of wind moving through the area.

The Association of Australian Acoustical Consultants said that "those investigations conclude that infrasound levels adjacent to wind farms are below the threshold of perception and below currently accepted limits set for infrasound".

Those limits are levels of infrasound that people encounter already, created by natural sources like breathing, wind, and waves, as well as mechanical sources like aircraft, traffic, and fossil fuel industry. The study noted that wind turbine noise is all relative:

Our environment has lots of infrasound already in it, the levels generated by wind farms from our point of view are quite low in comparison and they're no higher than what is already out there in the natural environment.,.. "People themselves generate infrasound through things like their own heartheat, through breathing and these levels of infrasound can be substantially higher than an external noise source."

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