Letter to Editor: Issues of wind turbine noise

Mike Barnard 
 IBM Global Business Services, Singapore

Correspondence Address:
Mike Barnard
IBM Global Business Services
Singapore

Full Text

Sir,

I am writing with regard to a recently published study in your journal: Effects of industrial wind turbine noise on sleep and health (Year: 2012 ǀ Volume: 14 ǀ Issue: 60 ǀ Pages: 237-43, Web Publication October 29, 2012).

Having reviewed the article and discussed it with several people, I believe the data presented does not justify the very strong conclusions reached by the authors. Given that this study is already being circulated by the media and lay anti-wind activists, there is a potential for its implications to be misconstrued, which will exacerbate community anxiety and potentially precipitate the very problems the authors are seeking to investigate. Indeed this is a core and circular issue that the authors have failed to address (see point 3 below).

Potential problems include:



Use of the loaded term 'industrial wind turbine' is not appropriate. This is not an accepted term in literature - 'wind turbine', 'utility-scale wind turbine,' or 'wind turbine generator (WTG)' must be used instead.All three authors - Michael Nissenbaum, Christopher Hanning and Jeff Aramini - have a history of anti-wind activity including involvement in the lobby group, The Society for Wind Vigilance. This does not necessarily invalidate their study, but must be disclosed given the potential for investigator bias. [1],[2],[3]One of the authors (Nissenbaum) has been active in investigating the Mars Hill and Vinalhaven wind farms previously. [4],[5] This is not disclosed, and therefore, it is possible that previous contact with the investigators and other anti-wind activists has primed the responses of participants (inducing a nocebo effect), or biased the sample. Analogous studies looking at electromagnetic radiation (EMR) rather than noise have shown that concern about EMR, rather than the EMR itself, can affect sleep quality, Danker-Hopfe et al., 2010.The authors assert that there is a 'strong' dose-response relationship. I cannot see how this is justified, given the presented data. In contrast to the conclusions, [Figure 1] and [Figure 2] in the paper (recreated below for clarity) show a very weak dose-response, if there is one at all. The near horizontal 'curve fits' and large amount of 'data scatter' are indications of the weak relationship between sleep quality and turbine distance. The authors seem to use a low P value as a support for the hypothesis that sleep disturbance is related to turbine distance. A better interpretation of the P value related to a near horizontal line fit would be that it suggests a high probability of a weak-dose response. Correlation coefficients are not given, but should have been given, to indicate the quality of the curve fits.{Figure 1}{Figure 2}In light of the above, I feel that there is insufficient evidence to suggest a causal relationship between wind turbine noise and sleep quality. Other potential causal factors such as resident sentiment toward wind turbines or the level of anti-wind farm lobbying have not been investigated. Establishing a time course is not enough, given that nocebo effects would be expected to occur over a similar time frame.It is worth noting that the Pittsburgh Sleep Quality Index material asserts that any score over 5 indicates a poor sleeper, and that both the control group and the group closer to the wind generators had scores over 5 on average. The implication is that rural dwellers on average are poor sleepers. This is a more significant finding than any related to wind turbines. The Epworth scores confirm this finding, yet it goes unnoted by the authors. [6],[7]

While I understand that independent review was sought by Noise and Health for this piece of research, it is worth noting that the reviewers thanked by the authors - Dr. Carl Phillips, Rick James and Robert Rand - also have undisclosed strong histories of anti-wind activity, both as paid expert testifiers and as service providers to complainants, and two of the three are also on the Advisory Board of the Society for Wind Vigilance. [8],[9],[10]

References