I recently read a scientific paper whose authors researched the effects of infrasound on their subjects. They concluded that people complain about turbines making them sick because that’s what they expect. This was a psychological study where the researchers put people in a “listening room” and exposed them to infrasound from a sound system – they did not use infrasound actually generated by wind turbines. I had problems accepting their conclusion. I don’t think that just because a small number of people were influenced by their psychological expectations, that it is valid to conclude that people are not negatively impacted by long periods of infrasound from wind turbines. An audiologist also had a lot to say about the inaccuracy of the study. Dr. Jerry Punch’s critique convinced me that the Crichton study was fatally flawed.
There is much to read and understand on the health issues from wind turbines. Dr. Salt’s site is perhaps the best that I’ve seen to understand HOW and WHY people are affected by infrasound from wind turbines.
Dr. Salt is a researcher with the Dept. of Otolaryngology at Washington Univ. in St. Louis. His research has been funded by NIH for over 20 years with a focus on how inner ear function depends on the fluids of the ear that bathe the sensory cells. His studies show that infrasound at frequencies as low as 1 Hz had a major influence on the function of the inner ear, even at inaudible levels. His work confirms that the inaudible, infrasound component of wind turbine noise stimulates the ear at levels that are not heard.
Finally, this report is pretty amazing. It is not only interesting from an historical perspective, as this study was presented in 1987. But, this study is very important because it discusses that people inside their home are more susceptible to low-frequencies generated by wind turbines.
The low frequency issue has been known since the late 1980’s, but wind companies are ignoring it!!!
This paper was presented by N.D. Kelley at the Windpower ’87 Conference and Exposition October 5-8, 1987, San Francisco, CA. The research was prepared for the U.S. Department of Energy.
“Given our initial experience with the low-frequency impulsive noise emissions from the MOD-1 wind turbine and their impact on the surrounding community, the ability to assess the potential of inferior low-frequency annoyance in homes located near wind turbine installations may be important. Since there are currently no universally accepted metrics or descriptors for low-frequency community annoyance, we performed a limited program using volunteers to see if we could identify a method suitable for wind turbine noise applications. We electronically simulated three interior environments resulting from low-frequency acoustical loads radiated from both individual turbines and groups of upwind and downwind turbines. The written comments of the volunteers exposed to these interior stimuli were correlated with a number of descriptors which have been proposed for predicting low-frequency annoyance. The results are presented in this paper. We discuss our modifications of the highest correlated predictor to include the internal dynamic pressure effects associated with the response of residential structures to low-frequency acoustic loads. Finally, we outline a proposed procedure for establishing both a low-frequency “figure of merit” for a particular wind turbine design and, using actual measurements, estimate the potential for annoyance to nearby communities.”