Posted on February 9, 2010 by Roger Ferland
One of the big hurdles for further development of wind power in the U.S. is landowner objections to placement of turbines near their homes. The rationale du jour for such objections is that the sound produced by turbines causes a broad range of health effects. In particular, objectors point to infrasound, which is sound generally below the level of human perception. A recent case in Wisconsin was one of the first in the country to test the objectors’ theories. When a Wisconsin utility applied for permission to build 90-turbine development north of Madison, objectors argued for extremely low limits for wind turbine sound and a mile-and-a-quarter setback, limits which would have made the project impossible. The principal proponent of the theory that wind turbine sound causes physiological harm is a New York pediatrician, Nina Pierpont. Dr. Pierpont has written and self-published a book, entitled “Wind Turbine Syndrome: A Report on a Natural Experiment,” which chronicles complaints by 10 families around the world who have lived near wind turbines. As presented by Dr. Pierpont, the symptoms include everything from headaches to nausea, tachycardia, irritability and panic episodes associated with sensations of movement or quivering inside the body. Dr. Pierpont argues that infrasound works in two principal ways to cause these symptoms: first by exciting the human vestibular (balance) system; and second vibrating the diaphragm and organs, thereby passing on confusing messages to the body. Dr. Pierpont draws upon and supports the work of noise control engineers George Kamperman and Richard James, who, in various proceedings in the U.S. and abroad, advocate very low thresholds for sound from turbines (35 dBA, which is approximately the level of a quiet bedroom). In the Wisconsin case, objectors hired Mr. James to provide expert testimony, which he did, relying heavily on Dr. Pierpont’s theories. Quarles & Brady retained two experts to address sound issues on behalf of the utility. Dr. Geoff Leventhall is an acoustician, consultant and professor from the U.K. who has been involved in studying infrasound for nearly 50 years. Dr. Leventhall testified that neither of Dr. Pierpont’s theories make sense. In fact, he testified, the author of the study Dr. Pierpont relies upon for her vestibular disturbance theory specifically disclaimed that his work supported her conclusions. As for Dr. Pierpont’s theory that infrasound vibrates the diaphragm and organs, Dr. Leventhall testified that simple math dooms her argument. Sound from turbines results in movement of the diaphragm of less than 10 microns (one tenth the thickness of a human hair), while during normal breathing, the diaphragm moves several centimeters. Dr. Leventhall also pointed out that Dr. Pierpont’s analysis completely ignores another, much stronger, source of internal infrasound–the heart. Quarles & Brady also retained Dr. Mark Roberts, a Chicago-based epidemiologist, biostatistician and physician. Dr. Roberts testified that “wind turbine syndrome” is not a medical diagnosis supported by peer reviewed, published, scientific literature. He completed a review of the literature, and found no support for the claim that wind turbine sound causes physiological harm. Dr. Roberts also identified several flaws in Dr. Pierpont’s methodology, limiting the usefulness of her research, including selection bias and a failure to adhere to accepted epidemiological principles in developing her theories. Summarizing Dr. Pierpont’s work, Dr. Roberts concluded that it consisted of “opinions that are unsubstantiated,” and as he pointed out, “everyone has opinions.” Dr. Roberts warned against allowing such “science” to shape public policy. Both Dr. Leventhall and Dr. Roberts agreed that sound from wind turbines may annoy neighbors or disturb their sleep. Dr. Roberts summarized such concerns as follows: “The underlying complaint of annoyance is, in and of itself, not a disease or a specific manifestation of a specific exposure, but instead a universal human response to a condition or situation that is not positively appreciated by the human receptor.” Ultimately, while the Wisconsin Public Service Commission recognized that no development is without cost to those who live nearby, it adopted the utility’s suggestion of a 50 dBA sound threshold, with a lower 45 dBA threshold during summer nighttime hours, when neighbors are likely to have their windows open. These thresholds allow the utility to move forward with the project, while, in the Commission’s view, striking an appropriate balance between neighbors’ interests and those of the utility.