Review of wind turbine sound studies gives debate needed balance
This Letter to the Editor is from Paul Masotti, PhD, an Assistant Professor in the Department of Community Health and Epidemiology at Queen's University, Kingston, Ontario. It is reprinted here with permission of the author.
The Kingston Whig-Standard
February 09, 2012
Paul Masotti: Letter to the Editor
Conclusions of story not supported by public health agencies and medical community
I read the story "Wrecking our heaven" (Jan. 9) with interest and a feeling of being let down.
This article could leave readers with the conclusions that wind turbines cause ill health and are a health risk to the unborn. These conclusions are not supported by the available research and are not supported by public health agencies and the medical community. If the objectives of the Whig-Standard include both reporting and informing your audience about a health issue, I would argue that the paper failed. Possibly the following will provide what I believe is the needed balance.
Working with team members from the local public health agency, we completed a review of the international literature to find out what is known about wind turbines and potential health effects. We improved upon similar studies by broadening our scope to include documents from community-based organizations, peer-reviewed scientific journals, grey and self-published research, government and industry technical guidelines, and noise and health research done in other settings.
It is correct that there are few good quality research studies that evaluate potential health effects from exposure to windturbines. This has resulted in a variety of case series and self-reporting studies with problems that would earn them a failing grade in a university-based research methods class. The designs of these studies could not be used to reach a cause-and-effect conclusion (for instance, that exposure will likely result in ill health).
At this point, it may help to present two examples (one is the Ontario self-reporting study) with different methods and different results. I will follow these examples with some of the results and take-home messages we generated based upon our review.
In a study of 725 Dutch residents, Van den Berg et al. (2008) evaluated factors associated with wind turbine annoyance, how they perceived the wind farm, and self-reported health. Strengths of the study included the large number of participants (725) who were randomly selected from 50,375 residences, and placing people in one of four increasing noise exposure groups ranging from 25 to 45 decibels. (Note: in evaluating whether something will cause ill health, we would generally expect more of the something, such as noise, will result in more frequent or severe illness.)
A major strength was the "masking" of the study, so subjects did not know the focus was on wind turbines, and an analysis of people who declined to participate.
A main study result was that health effects -- chronic disease, diabetes, high blood pressure, cardiovascular disease, migraines, psychological distress, stress and difficulty falling asleep -- were not associated with wind turbine sound levels. The results did indicate that both sleep interruption and "annoyance" were associated with increasing noise levels. However, an additional and interesting finding was that the people who lived in the highest noise category, 45 decibels, were less annoyed than those in the lower noise locations. Additional research revealed that people in this category were receiving financial benefits from the operation of the wind turbines.
In the self-reporting survey, adverse health effects with industrial wind turbines and the need for vigilance (2010), Krogh, Gillis, Kouwen distributed health survey contact flyers to people who lived near wind farms. The flyers included statements such as victims suffering from adverse health effects. People who responded were provided with a survey that included a symptoms/ illness list where they could check off symptoms they believed appeared or worsened after the wind turbines were made operational. People also provided the distance to the nearest wind turbine.
Problems with this study that make the results questionable include allowing people's opinions about wind turbines to influence their identification and participation in the study; allowing more than one person per residence; and using a symptom check list versus asking them to report symptoms. In addition, the language in the flyers and the report clearly indicated a lack of scientific objectivity.
A main result in this study was that 80.3% (106 of 132 people) reported adverse health effects they attributed to the wind turbines. Given the language in the flyers, one interesting result was that 26 people reported no health effects. To address this, we looked at the average distance from the nearest wind turbine between the ill-health and no-health-effects groups as an approximation of noise level exposure, since decibel levels were not provided and knowing that noise levels decrease over distances.
The report indicated that there was a 4.5-metre average difference between the two groups (820.6 metres away from a turbine for the ill-health group and 816.1 metres distant for the group reporting no ill health). If this were a well-conducted, large-sample study, this insignificant difference would suggest that both groups were exposed to the same noise emissions and consequently that health differences between the two groups are not related to noise from the wind turbines.
The research suggests these take-home messages:
The wind turbine and health research, research on wind turbine noise emissions, and supporting evidence from the noise and health research do not provide evidence and do not suggest the likelihood that wind turbine noise that meets government guidelines will result in ill health. The research does indicate that self-reported differences in subjective health complaints between people exposed or not exposed to noise are dependent upon the person's perceived control over the noise and were independent of the noise level itself.
The World Health Organization has described annoyance as a health effect, and the wind turbine research indicates that as wind turbine noise increases, higher percentages of people report being very annoyed. This research also indicates that the percentage of people who become fairly or highly annoyed is low (6.7% at 37-40 decibels; 15% at 40 decibels) and that other subjective individual factors that equally explain annoyance include: whether one can see the wind turbines, fear, culture, ability to control the noise, clinical and sub-clinical mental health issues, perceived importance and financial benefits. Given this, we cannot say the annoyance is the result of the wind turbine noise alone.
The case series and other studies that are highly reported on the Internet cannot be used to reach conclusions of cause and effect and most had significant methodology problems that decrease confidence in results and conclusions.
We need to decide what noise levels we will permit under different conditions and based upon good health evidence. As part of this, there is need of a formal complaint-resolution mechanism that can provide effective remedies for people exposed to levels that exceed the guidelines. This should involve sound measurements at the residences and a predetermined resolution process that includes shutting down the wind turbines under some conditions.
I would like to finish with results from a study that seems relevant to the last sentence in the Jan. 9 article: "They are wrecking our heaven. Don't let them do it."
The grounded theory study by Pedersen, Hallberg and Waye (2007) evaluated people's perceptions of wind turbines and the purpose of land. An interesting result of this study was the identification of two different groups of people. One saw the countryside as a place for economic growth and where one must accept disturbances typical of the countryside such as: flies, odour from farms, and (in that study) also noise from wind turbines. The second group placed more value on their home environment as a peaceful, quiet place where they create a home versus the home being just a place to live.
Those in the second group were more likely to feel the wind turbines were an intrusion and to express feelings of anger, uneasiness, fatigue and negative emotions, and this affected well-being and quality of life. They also were more likely to believe they did not have enough input or influence regarding the planning of the wind farms and that they were misled regarding the impact of the wind turbines on them.
My question is this: would this discussion be taking place if the wind turbines were the same size as telephone poles?
Paul Masotti, Kingston
Anti-wind-farm "astroturfers" in Australia, February 27, 2012
NBC4's 'iReporter' lacks context on wind turbine sound, February 14, 2012
Fact check: Bryce misleads again on land, sound, resource use, January 31, 2012
Massachusetts clears wind of health effects after independent experts review evidence, January 20, 2012
Opinion: Dr. W. David Colby: Turbines and health, December 2, 2011
Canadian researchers: No direct link between wind turbines and adverse health impacts, November 29, 2011
Wind power: A quiet solution to climate change, June 27, 2011
Sierra Club Canada 1.1: Time to confront anti-wind fear campaign, June 15, 2011
Environmental Defence (Canada): 'No basis' for health impact claims, June 6, 2011
Sierra Club Canada: Time to confront anti-wind disinformation campaign, June 3, 2011
WHO guidelines on sound are ... guidelines, March 28, 2011
Scientists, doctor weigh on wind and health, November 30, 2010
Wind Turbines and Health, fact sheet
Maine physician: distortion in anti-wind health claims, November 3, 2010
Australian health agency: Turbine sound has no health effect, July 6, 2010
UK report debunks wind turbine syndrome, June 9, 2010
Wind gets clean bill of health from Ontario, May 20, 2010
Expert panel concludes wind turbine sounds not harmful to human health, December 15, 2009