Eco Realty Blog Industrial wind turbines and Lusitano horses

A land consultant I recommend to clients, Bill Lattrell of Heath, wrote an excellent report on industrial wind turbines. It is so impressive that I feel I have to link it here for interested readers. Bill and his co-author Steve Ryack wrote this report for the town of Heath in 2013, but their conclusions unquestionably still hold. A few paragraphs particularly jumped out at me:People complain of a peculiar and particularly debilitating quality to the sound from turbines. A paper by Thorne in the journal, "Bulletin of Science and Technology" August 2011, shows that unlike other industrial noises, the amplitude and frequency of wind turbine noise is continuously modulated (AM and FM). That is, the pitch and the loudness are not steady but change continuously. Another example of AM and FM modulation is the sound of a police cruiser or fire truck. The continuous change of pitch and loudness makes it very hard for people to become desensitized or habituated to the sound, as occurs with other industrial sounds. On the contrary, sensitization over time appears to occur more frequently when pitch and loudness are modulated. Also, as wave frequency decreases, the effectiveness of barriers such as walls and windows to attenuate sound is diminished. Windows and walls are actually induced to vibrate at lower frequencies. Decreasing wave frequency is the same as increasing wavelength. As the wavelength approaches the dimensions of rooms and houses, standing waves are set up within these structures. As the waves bounce back and forth in these enclosed spaces their amplitude (loudness) increases, much as the height of a child on a swing increases each time it is given a push. They become resonant chambers in their own right, resulting in indoor noise levels higher than those outdoors.