Page 26 - Volume 9, Issue 3

A standard calibrated Type 1 Sound Level Meter, of course, exactly to state or local requirements. My reaction is, “Why don’t you come back when there is a new regulation and an instrument capable of evaluating what these unfortunate neighbors are feeling and reporting?”
There is a new institute formed at the University of Waterloo in Ontario on exactly this subject and Dr. Nina Pierpont of Johns Hopkins Medical School has written in Counter Punch Magazine:
“... The vestibular organs – the semicircular canals, saccule, and utricle – function as Mother Nature’s gyroscope, controlling our sense of motion, position, and balance, includ- ing our spatial thinking. (Remember when you got carsick as a kid? Or seasick?)
Humans share these enigmatic organs with a host of other backboned species, including fish and amphibians. Some scientists indeed see them as a kind of pan-species master key for an extraordinarily broad range of brain function – amounting to a sixth sense.
One of those functions, it now appears, is to register and respond to the sounds and vibra- tions (infrasound) we don’t consciously hear, but feel – as from wind turbines. For many people, the response is swift and disastrous.”
The last line says it all – what you can’t hear can hurt you – stop talking around the subject, mitigate as required to the comfort of the neighbors, and
wait for more points to get the curve right.
It should also be noted that, as Dick Campbell no doubt knew, the regulations are made necessarily after you have a way to measure it. The privately-funded study by Ambrose and Rand used dBG-weighting to isolate the low-frequency components and infrasound. Note: Dick Campbell died on October 11, 2012.
The Massachusetts Department of Environmental Protection (DEP) performed acoustical tests on neighboring properties in Falmouth in March 20127. The study compared the “maximum levels” (Lmax) at night, assumed to be from the turbine, with measured background (L90s) at night. The read- ings were A-weighted slow response, and were attended. The difference measured at one location from Wind 1 was more than 10 dB above the background, the DEP’s definition of noise impact. The use of “maximum level” drew some criti- cism from the wind developer community. It is unfortunate that the DEP used this term, because the data were time- stamped 1-second A-weighted equivalent levels (Leqs), not maximum levels. The DEP report was obtained from their website. In fact, most of the “maximum levels” were disqual- ified by the observer as belonging to other noise sources. A better term might have been “observed level.”
Eventually, both wind turbines were shut down at night. At the end of April 2013, the Town of Falmouth was consid- ering tearing down the two city-owned turbines for $8 mil- lion. The vote failed, but $100,000 was approved to further study the issue.
Other Recent Wind Turbine Noise Studies
In the Wind Turbine Noise session at the International Congress on Acoustics in Montreal, Canada, in June 2013, there were some interesting observations made by some of the authors. George Hessler and Paul Schomer8 independent- ly arrived at a design goal of 40 dBA or less at the nearest res- idence from wind turbines. Paul Schomer later presented data from a wind farm in Shirley, Wisconsin. In his section on adverse physiological effects, he writes:
Recently, measurements were made at a small wind farm in Shirley, Wisconsin. These measure- ments were made in the homes of three families who had abandoned their homes because they could not tolerate physiological results caused by the acoustic emissions of wind turbines. This same story is being played out in a seemingly random fashion around the world. Between Hessler Associates and Schomer Associates, five wind farms are known to have reported problems similar to those at Shirley. Perhaps 1% of wind farms have reported problems like those at Shirley; the remain- ing 99% have not documented such problems, and the reasons that a small percentage have these prob- lems are not known. And within those wind farms that have these problems, only a small segment of the populations is actually affected to the degree exhibited at Shirley, again on the order of perhaps 1% to 3% of households.
From the residents of Shirley we learned: (1) most residents did not hear the turbines; residents said they could sense when the turbine was on, (2) the effects did not vary with changes in the orienta- tion of the turbines with respect to the homes, (3) the general symptoms of those affected adversely by the wind turbine emissions were virtually the same as symptoms for motion sickness, and (4) afflicted residents were prone to motion sickness.
This told us that (1) the resident had no noise annoyance because they did not hear any wind tur- bine noise, (2) the wavelength of the “sound” must be large — on the order of 100 m, and (3) there must be a mechanism by which this very low fre- quency infrasound can cause symptoms of motion sickness in people. To this end, we found a study developed by the Navy showing that linear acceler- ations at 0.7 Hz were moving well into the nau- seogenic region, and that the frequency that induces motion sickness at the lowest acceleration is approximately 0.2 Hz.
The turbine model used in Shirley, the Nordex N-100, is among the largest ever installed in resi- dential areas, and has a blade passage frequency of 0.7 Hz, and corresponding rotor frequency of 0.23 Hz. The 0.7 Hz was evident in the measurements during times when the turbines were at full power, but not when the turbines were throttled back. The 0.23 Hz was only evident part of the time.
At this point we must note that after over 4000
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