Page 24 - Volume 9, Issue 3

frequency spectrum but are instead related to the response of the vestibular system to the low fre- quency noise emissions. The vestibular system appears to be stimulated by responding to these pressure pulsations rather than by motion or dis- ease, especially at low ambient sound levels. Dysfunctions in the vestibular system can cause disequilibrium, nausea, vertigo, anxiety, and panic attacks, which have been reported near a number of industrial wind turbine facilities. The study empha- sizes the need for epidemiological and laboratory research conducted by medical health professionals and acousticians working together who are con- cerned with public health and well-being. It is espe- cially important to include a margin of safety suffi- cient to prevent inaudible low-frequency wind tur- bine noise from being detected by the human vestibular system.
What is noteworthy is that the researchers themselves expe- rienced the adverse health effects from the wind turbines.
About the same time as the private study was going on, the Commonwealth of Massachusetts Department of Environmental Protection and the Massachusetts Department of Public Health commissioned a wind turbine health impact study, using an independent expert panel.
5
Their report is dated January, 2012 . Their members were
from Harvard Medical School, Massachusetts General
Hospital, Boston University, Boston University School of Public Health, University of Massachusetts at Amherst, University of New England, and Harvard School of Public Health. The panel focused on public health based on scien- tific findings. It also limited its analyses to land-based instal- lations. The panel sought human epidemiological studies in the scientific literature. Most of the conclusions in the study were that there was limited or insufficient evidence. Some comments on health effects of wind turbines from the execu- tive summary of the report:
2. There is limited evidence from epidemiologic studies suggesting an association between noise from wind turbines and sleep disruption. In other words, it is possible that noise from some wind turbines can cause sleep disruption.
3. A very loud wind turbine could cause disrupted sleep, particularly in vulnerable populations, at a certain distance, while a very quiet wind turbine would not likely disrupt even the lightest of sleepers at that same distance. But there is not enough evidence to provide particular sound-pressure thresholds at which wind turbines cause sleep disruption. Further study would provide these levels.
4. Whether annoyance from wind turbines leads to sleep issues or stress has not been sufficiently quantified. While not based on evidence of wind turbines, there is evidence that sleep disruption can adversely affect
Fig. 1. The photo is by the author of a wind turbine in Hull, Mass.
Wind Turbine Noise 23