Monday, September 19, 2011

New study: no evidence for "wind turbine syndrome"

Continuing with my focus on wind energy, a new study “Health Effects and Wind Turbines: A Review of the Literature” has just been published in the academic journal Environmental Health (14 September 2011).

The study, by Loren D Knopper and Christopher A Ollson, reviews the peer-reviewed scientific literature, government agency reports, and the most prominent information found in popular literature on the subject. As the abstract notes, “People interested in this debate turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet.”

In a classic understatement, the abstract notes that “conclusions of the peer reviewed literature differ in some ways from those in the popular literature.”

On the one hand, “no peer reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects.” On the other, “In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured.”

“While it is acknowledged that noise from wind turbines can be annoying to some and associated with some reported health effects (e.g., sleep disturbance), especially when found at sound pressure levels greater than 40 db(A), given that annoyance appears to be more strongly related to visual cues and attitude than to noise itself, self reported health effects of people living near wind turbines are more likely attributed to physical manifestation from an annoyed state than from wind turbines themselves.”

The abstract concludes that “assessing the effects of wind turbines on human health is an emerging field and conducting further research into the effects of wind turbines (and environmental changes) on human health, emotional and physical, is warranted. “

The review included literature on infrasound, audible noise, and also Nina Pierpont’s book that coined the term “wind turbine syndrome” and others such as Alves-Pereira and Castelo Branco from Portugal who believe they have identified something called “Vibro-Acoustic Disease”.

However, the review finds of Pierpont and the Portugese study that, “to date, these studies have not been subjected to rigorous scientific peer review, and given the venue for their distribution and limited availability of data, it is extremely difficult to assess whether or not the information provided is reliable or valid.

“What is apparent, however, is that these studies are not necessarily scientifically defensible: they do not contain noise measurements, only measured distances from study participants to the closest turbines… they suffer from a small number of participants and appear to lack of objectivity as authors are also known advocates who oppose wind turbine developments.

“…In fact, the selection process is highly biased towards finding a population who believes they have been affected by turbines.”

While this study recommends further research, it does not lend credibility to those campaigners who are seeking to associate wind farms with severe health risk. In fact, it mostly supports the psycho-social aspect of illness that is associated with wind farms, rather than direct physiological health effects.

“In the peer reviewed studies, annoyance tends to peak in the >35 dB(A) range but tends to be more strongly related to subjective factors like visual impact, attitude to wind turbines in general (benign vs. intruders) and sensitivity to noise rather than noise itself from turbines.”

The study concludes that research “should be undertaken by multi-disciplinary teams involving, for example, acoustical engineers, health scientists, epidemiologists, social scientists and public health physicians. Ideally developers, government agencies, consulting professionals and non-government organizations would form collaborations in attempt to address these issues.”

The study is 22 pages long, including a list of 41 references reviewed, and can be downloaded directly as a PDF file here.

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