Leventhall, Witness Statement, Erickson, Chatham-Kent, Kent Breeze Corp
WITNESS STATEMENT OF
Dr. Geoff Leventhall Independent acoustical consultant, January 17, 2011
Case Nos.: 10-121 and 10-122
In the matter of appeals by Katie Brenda Erickson and Chatham- Kent Wind Action Inc. filed on November 29, 2010 for a Hearing before the Environmental Review Tribunal pursuant to section 142.1 of the Environmental Protection Act, R.S.O. 1990, c. E.19, as amended (“EPA”) with respect to Renewable Energy Approval Number 7988-8AVKM5 (“REA”) issued by the Director, Ministry of the Environment (“MOE”), on November 10, 2010 to Kent Breeze Corporation and MacLeod Windmill Project Inc. (“Kent Breeze Wind Farms”) c/o Suncor Energy Services Inc. (“Suncor”) under section 47.3(1) of the Environmental Protection Act (“EPA”), regarding the construction, installation, operation, use, and retiring of eight wind turbine generators located at Part Lots 8-11, Concession 1 and Part Lots 4-6, Concession 1 & 2, in the Township of Camden, Municipality of Chatham-Kent, Ontario.
INTRODUCTION
1. I have no personal interest in the outcome of this appeal. I intend to appear before the Environmental Review Tribunal (the ERT) and be subject to direct examination and cross-examination. My evidence will be factual and opinion evidence. I have read the ERT’s Practice Direction for Technical and Opinion Evidence and I provide this statement in accordance with that Practice Direction. Attached as Exhibit “1” to this witness statement is a Form 5 that I signed in accordance with the ERT’s Rules of Practice.
AREA OF EXPERTISE
2. My area of expertise is noise and vibration and subjective response to noise, with special expertise in infrasound and low frequency noise and wind turbine noise. I have been developing my understanding of infrasound and low frequency noise and their effects for over 40 years. I was the founding editor of the Journal of Low Frequency Noise and Vibration in 1982 and edited it for the first 18 years. My interest in wind turbines began in the mid 1980’s when I carried out work on subjective responses. In the past few years I have been invited to sit on three committees concerned with the effects of noise on health. Two of these were for the UK Government, the third was for the AWEA- CanWEA report.
3. I was co-author of the Wind Turbine Sound and Health Effects An Expert Panel Review prepared for the AWEA and CanWEA (Colby et al., 2009), and to date I believe the conclusions that were reached in that report remain valid.
POSITION AND QUALIFICATIONS
4. I presently hold the position of noise and vibration consultant. A copy of my current curriculum vitae is attached as Exhibit “2” to my witness statement.
5. I graduated in physics and have MSc and PhD degrees in acoustics from London University (UK).
6. In my capacity as an acoustical consultant, my work includes investigation of general problems of noise and vibration with particular emphasis on low frequency noise. Much of my work is interacting with people who are troubled by noise. Another current project is the development of sounds to increase the safety of quiet electric vehicles and I serve on the United Nations Economic Commission for Europe – Groupe de Recherche de Bruit – Quiet Road Transport Vehicles (UNECE GRB QRTV).
7. I am also the initiator and organiser of the International Series of Conferences on Wind Turbine Noise, which are held biannually. The fourth in the series will be in Rome in April 2011.
8. My career has been split almost equally between academic and consultancy work. During my time as an academic at London University I personally supervised 30 PhD students to completion of their theses in acoustics.
CHRONOLOGY OF INVOLVEMENT AND DOCUMENTS REVIEWED
9. I was contacted by Counsel for Suncor on 15th December 2010 and asked to provide an opinion in this matter.
10. I have reviewed the documents listed in Schedule “A” attached as Exhibit “3” to this witness statement which were provided to me by Counsel for Suncor.
11. I have also reviewed the documents listed in Schedule “B” attached as Exhibit “4” to this witness statement during the preparation of this statement.
DISCUSSION
12. I have prepared this witness statement based on the Appellants’ disclosure statement of December 20, 2010. My review reveals very little about the evidence that they intend to call with respect to the issue of whether engaging in the Kent Breeze Wind Farm in accordance with the REA will cause serious harm to human health. As such, this statement will consist of a general review of the state of the science with respect to noise impacts of Wind Farms, in particular the effects of infrasound and low frequency noise, followed by my opinion as to the evidence with respect to Kent Breeze as best as I can at this time
Misunderstandings about Wind Turbine Noise
13. Over the past 10 years, and particularly in the last 5 years, the noise from wind turbines has been subject to more strange and unsubstantiated claims of harm than any other noise has been. These claims are centred on pathological effects of infrasound and low frequency noise, specific effects on the body, and were directed at other sources before wind turbines came on the scene. Some of the misunderstandings are due to misleading presentations by scientists over 40 years ago, which were interpreted selectively by the media in order to give exciting news stories. (Gavreau, 1968) (Gavreau et al., 1966).1 A succession of “reinterpretations” over a period of five or six years led infrasound and low frequency noise to be described in popular science texts as a cause of death, whilst also possessing the ability to knock down buildings (Watson, 1974). This aura of mystery and danger still persists today, deep in the minds of many people, where it waits for a trigger to bring it to the surface. The most recent trigger has been wind turbines.
14. Despite the long standing claims, no direct adverse effect of noise has been demonstrated at the levels produced by wind turbines, but there is much supposition. Infrasound occupies a special place in the communal psyche of various groups of people, who have accepted the suggestion that there is something “creepy “ or even ”dangerous” about infrasound (Leventhall, 2006).
15. A main publicist asserting that there are direct adverse effects of infrasound on the body has been Dr. Nina Pierpont, who began these claims when, about six years ago, she came to local prominence as the leading campaigner against a proposal to erect wind turbines near to her home town of Malone, NY. Since that time, Pierpont has continued her publicity campaign and risen to further prominence, both nationally and internationally. Some of the methods she used to achieve this position were questionable, particularly her misuse of other people’s work, which led to one scientist publicly repudiating the manner in which she had misrepresented his findings (Todd, 2009). My own study of Pierpont’s writings has led me to the conclusion that she has a rather poor understanding of acoustics. Her main work has been the self-published, popular science book, “Wind turbine Syndrome”, in which she puts forward hypotheses on assumed effects of inaudible infrasound acting directly on both the vestibular system in the ear and related balance receptors in the body (Pierpont, 2009). I have carefully studied Pierpont’s hypotheses and find them to be weak and unfounded.
16. An Australian study of Rural Wind Farms, concluded on page 121 (New South Wales. Parliament. Legislative Council, 2009 (December))
7.56 The Committee notes the concerns expressed by Inquiry participants regarding ‘Wind Turbine Syndrome’. The Committee further notes that research findings of ‘Wind Turbine Syndrome’ have not been published in a peer-reviewed journal.
7.57 The Committee is concerned that the significance of ‘Wind Turbine Syndrome’ is being unnecessarily exaggerated because Dr Pierpont is a medial doctor and has published a book on the issue, rather than any scientific merit of such a syndrome. As a result, a degree of fear is being instilled in communities that may host wind turbines. The Committee is concerned that, based on evidence received, this unwarranted fear may be causing greater health impacts than the presence of any actual ‘Wind Turbine Syndrome’.
17. A problem which arises from strong and persistent publicity of any kind, is the formation and manipulation of attitudes. In this case attitudes to wind turbine noise and the fears and concerns which flow from the dissemination of negative feelings. Further consideration of this is given below.
18. Pierpont’s book, and the views expressed in it, made it necessary for others to consider the reliability of her claims of pathophysiological effects of infrasound from wind turbines and the following studies were made:
a. Wind Turbine Sound and Health Effects An Expert Panel Review prepared for the AWEA and CanWEA (Colby et al., 2009). As mentioned above, I was a co-author of this study. Since this study was released I have read other work which relates to the effects of low frequency noise on people, for example the article by Salt and Huller (2010) and the presentation by Swinbanks (2010), but my opinion remains as described in the Panel Review. The reasons for this are explained later in my discussion of the work of Salt and Huller and of Swinbanks.
b. The Potential Health Impact of Wind Turbines (Chief Medical Officer of Health Ontario, 2010 (May))
c. Wind Turbines and Health (Australian_Government:_National_Health_and_ Medical_Research_Council, 2010 (July))
d. The Effects of Wind Turbine Sound on Health (Sims, 2010)
19. These four reports all concluded that there was no evidence of a direct pathophysiological effect from wind turbines, contrary to claims by Pierpont. The reports were met with dismissive comments from Pierpont and her supporters.
20. The difference in views between Pierpont and other objectors on the one hand and various experts on the other hand, has served to obscure and misdirect the wind turbine noise debate. It is very unlikely that anyone disputes that wind turbine noise, when it is audible, might annoy some people. The debate should not be about unproven illness, said to be caused by infrasound and low frequency noise, but about how and why an audible noise, which is normally a low level of noise, might become a problem to some people.
Annoyance by Noise and its Consequences
21. In general, there is a very little annoyance or disturbance from noise when the noise is at a very low level. As the noise level increases, more people become annoyed. The detail of how annoyance varies with noise level is usually determined from a combination of noise level measurements and surveys of subjective reactions. There is normally a great deal of scatter on the results, but an average is found and the well known response curve is developed, relating the level of a noise with the percentage of people annoyed. An early example of this type of curve is shown in Fig. 1 for environmental noise, mainly transportation. This curve has been chosen as illustration, as it shows the scatter on the results, which is often not included in more recent examples.
The ordinate is the percent of persons highly annoyed and the abscissa is the noise level, where Ldn is a combination of day and night noise which gives additional weighting to the night noise.
22. The response to wind turbine noise is often compared with the response to transportation noise, but as wind turbines are often referred to as industrial wind turbines, it is appropriate to compare their annoyance with annoyance from other industrial sources, as has been done by Janssen and colleagues (Janssen et al., 2009). Fig. 2 from Janssen et al., gives the comparison of annoyance by wind turbine noise with annoyance from other industrial sources. Here the ordinate is in Lden, which is similar to Ldn, but separates out the evening period, giving it a penalty in comparison with the day time levels, whilst the night time levels have a greater penalty.
23. Fig. 2 shows that, up to an excess of 40dB Lden, there is little difference in the annoyance of wind turbines and other industrial sources. It could be argued that the divergence between the two types of source at higher levels is influenced by the location of most industry in the more populated areas, where background noise is higher and expectations are lower. Note that the 10% highly annoyed level, which is often used in the development of noise criteria, is indicated by the dotted horizontal line and is at about an Lden of 48dBA externally for wind turbine noise heard indoors.
Recent Statements about Infrasound and Low frequency Noise
24. In the past year there have been two new entrants in the debate on the audibility of infrasound and its potential for disturbance. Dr. Malcolm Swinbanks claims that a person can hear wind turbine noise when it is below the normal hearing threshold. Professor Alec Salt, a neuroscientist specialising in hearing, has shown that the outer hair cells respond to infrasound at lower levels than those which can be heard. Consider what they have said.
25. Swinbanks bases his statements on his understanding of the work carried out by NASA in the early 1980s, when experimental wind turbines became operational. Swinbanks proposes a penalty of 7-10dB on the normal hearing threshold, specifically for listening to wind turbines. This results from a misunderstanding of the NASA work, which was for the short and sharp pulses of sound which were generated by the, now discontinued, downwind turbines as a blade passed the tower.
26. Salt has an intriguing approach, because the scientific caution which he shows in his published papers is absent from his web page, where he takes a strong “infrasound is harmful” stance, such as in http://oto2.wustl.edu/cochlea/wind.html, where he writes:
“The reason why wind turbine noise is more annoying than a refrigerator is because the wind turbine produces high levels of INFRASOUND!”
27. Salt’s scientific paper on infrasound and the ear is more cautious (Salt and Hullar, 2010). The complete conclusion from this paper is set out in Exhibit “5”. The first sentence of that conclusion reads as follows (OHC are the outer hair cells in the inner ear):
“The fact that some inner ear components (such as the OHC) may respond to infrasound at the frequencies and levels generated by wind turbines does not necessarily mean that they will be perceived or disturb function in anyway “.
28. The PowerPoint presentation from his paper given at the conference on Adverse Health Effects and Industrial Wind Turbines in Picton, October 29 –31, 2010, presented a different viewpoint in which he directly linked Wind Turbine Syndrome with infrasound. See: http://www.windvigilance.com/downloads/symposium2010/swv_symposium_
presentation_infrasound_your_ears_hear_it_2.pdf
29. The conclusions of his conference paper included:
“We need to stop ignoring the infrasound component of wind turbine noise and find out why it bothers people!!”
30. However, no evidence has been given, by Salt or any other researcher, that it is the infrasound component in wind turbine noise which might bother people. There is concern about infrasound, but only because people have been repeatedly told that it will harm them.
31. There is no reason to believe that Salt’s work on the hearing mechanisms of guinea pigs, which is the basis of the scientific paper (Salt and Hullar, 2010), is in any way faulty. We can accept his results, but may differ on interpretation. Salt’s conference claim that inaudible infrasound from wind turbines will have adverse effects on a human receptor, ignores the fact that similar levels of infrasound are common in many urban and other environments. A recent survey in Australia compared infrasound levels in locations remote from wind turbines with those in the vicinity of wind turbines and showed similar levels (Sonus, 2010). This is in line with my own earlier work, which showed the widespread occurrence of infrasound (Leventhall and Kyriakides, 1976). It must also be remembered that human evolution has been in the presence of natural infrasound.
32. The occurrence of the same inhibitory mechanism of outer hair cell action, in mammals as diverse as guinea pigs and humans, indicates that it is likely to be an ancient development, dating to a common ancestor, and with the aim of protecting against events which might affect our further progress. Salt and Hullar explain that the outer hair cells act to elevate the hearing threshold for low frequency noises and then propose that adverse effects may result from this. They do not consider that, without this inhibitory action, we would hear the naturally occurring low frequency and infrasonic noises which surround us and which would then mask important information related to danger and communication.
The Mars Hill Windfarm
33. I am familiar with Dr. Nissenbaum’s work investigating the Mars Hill Wind Farm. He has put much effort into investigating the Mars Hill Wind Farm, and has presented his results at a number of Hearings. A recent example of Dr Nissenbaum’s testimony is that for the Red Lily Saskatchewan Appeal. I have reviewed the judgement associated with his testimony.
34. Based on my review of the judgement, I have not seen any new scientific evidence or claims within my area of expertise. The Appellants say that Dr. Nissenbaum now has additional evidence from Mars Hill which will relate effect to distance from the wind turbines. I intend to review this evidence once it has been provided.
The concerns of Mr Palmer
35. I have reviewed Mr. Palmer’s materials. Mr. Palmer believes that an existing wind farm (Enbridge Ontario Wind Power) is non-compliant with its approval in a number of ways, including noise levels. As an independent, retired engineer he is not able to provide himself with the normal class of equipment which is expected to be used in acoustical investigations, but has put together an ingenious array of inexpensive hardware and free software, on which he relies. None of the acoustical equipment which he uses would be accepted as suitable for an Environmental Impact Assessment, although he does the best he can with it. Additionally, he is dependent on the sound card of his laptop, but does not give an assessment of the accuracy of this. Although he believes in the veracity of his measurements, I have concerns about their veracity.
36. The outcome of his measurements is that his readings give higher levels than those of the company Valacoustics, which was also involved in the wind farm.
37. He does show that levels increase with the operation of the windfarm, but that is to be expected. The question is whether they increase above a permitted level. Mr Palmer believes they do.
38. I am concerned that the wind turbines studied by Mr. Palmer are not those proposed and studied by Suncor for the Kent Breeze Wind Farm. The results of one wind farm with its turbine technology do not necessarily apply to another.
Statements by Dr James
39. I am familiar with the work of Dr. James.
40. There are a number of points in a paper presented by Dr. James at the Picton Conference of the Society for Wind Vigilance. (Society for Wind Vigilance, 2010). In one slide he writes:
““Sick Building” syndrome found that poorly or incorrectly designed HVAC systems in large office buildings resulted in inaudible modulated low frequency sounds in work areas. Workers reported symptoms similar to those for Wind Turbine Syndrome.”
41. At the time when sick building syndrome (SBS) had some prominence, mainly in the 1980s and the 1990s, all possible causes were explored, including noise. Dr. James seems to be basing his comments on a paper written by a freelance science journalist (Schwartz, 2008), which quotes Dr. Rob Niven of the UK. I have worked with Dr. Niven, who had found an association in a building between office areas in which there was both low frequency noise and symptoms of SBS. Dr. Niven and I planned to control low frequency air conditioning noise in a range of buildings using active noise control (antinoise), an area in which I am experienced, so enabling us to turn the low frequency noise on and off at will. The project was supported mainly by the UK Government, and also had financial input from ASHRAE in the USA2.
However, the project could not proceed because Dr. Niven was unable to find other buildings which displayed a similar association between low frequency noise and SBS.
42. The current view is that noise, low frequency or other noise, is not a factor in SBS. For example, the US Environmental Protection Agency does not mention noise in its publication on SBS (US Environmental Protection Agency, 2003).
2 I have been a Member or Corresponding Member of the ASHRAE Technical Committee on Noise for nearly 20 years
43. Dr. James’ attempt to use SBS to support his views on wind turbines, fails. The paper at the Picton conference also included the following:
“Sound Levels will be much higher than predicted “Multiple wind turbines complicate matters further. From relatively long distances, an assembly of machines appears as a point source….Closer to the turbines, they begin to act as a line source. The decay rate for line sources is 3-dB, not 6 dB for true spherical propagation.” Paul Gipe, Wind Turbines Coming of Age, ©1995 (page 379), was awarded the World Wind Energy Award in 2008 by the World Wind Energy Association. The standard wind turbine computer model used to estimate sound levels for Wind Project assumes “Spherical Propagation” not “Line Propagation” even though turbines are arranged in rows. This error means that the tables of sound levels and the contour maps grossly underestimate the true impact of the sounds on adjacent properties located along the rows.”
44. The final six lines appear to be a comment from Dr. James, not a quotation from Mr Gipe. It is true that, in the prediction of noise from wind turbines, each turbine is considered as a point source. But, the resultant noise at a receptor is obtained by summing the contributions of all the point sources arriving at the receptor. This is the way in which the sound received at a point from any complex source is derived, whether the source is a loudspeaker diaphragm, a line of wind turbines or a group of wind turbines. The complex source is considered as a collection of point sources and their separate effects are combined at any receptor point. It does not matter whether, for wind turbines, the arrangement is as a line or in any other configuration, the proper result is obtained, be this a 3dB, 6dB or any other fall off with distance.
45. The only association of a single wind turbine and a 3dB fall off with distance has been for very low frequencies, around 10Hz, where the initial fall off was at 6dB per doubling of distance, but at distances of around a kilometre or more, the rate of fall off was reduced due to the very long wavelength waves becoming trapped in a “channel” near the ground. At higher frequencies of 63Hz and 250Hz, the 6dB fall off was maintained up to 6km from the wind turbines (Hawkins, 1987).
46. I have also reviewed a recent paper which has Dr. James as a co-author: “Wind Turbine Noise. What Audiologists should know” (Punch et al., 2010). On page 23 of the paper it is stated, in reference to the sound of amplitude modulation:
“The audible portion of the whoosh is around 300Hz, which can easily penetrate the walls of buildings.”
47. There are two points here: (1) the whoosh is often centred at higher frequencies than 300Hz, but does vary; and (2) there is an earlier paper by Kamperman and James, ”The ‘How To’ Guide to Siting Wind Turbines to Prevent Health Risks From Sound”, which has not been published in a journal, but can be found on many wind turbine objector web pages (e.g., http://www.windaction.org/documents/17229 ). In this paper, Kamperman and James estimate the attenuation of the structure of a typical house at 315Hz and come up with over 30dB attenuation. I do not believe that any qualified acoustical consultant should describe a 30dB reduction as “easily penetrate”, as it represents an attenuation of the incident sound down to a small percentage of its original level. Kamperman and James Fig. 3 is reproduced for completeness below. The figure shows their own estimations of the low noise level at a residence situated 300m from a single 2.5MW wind turbine. Arrows have been added to indicate the difference between external and internal noise for the building at 100Hz and 315Hz, with windows closed. The arrows show an attenuation of about 12dB at 100Hz and more than 30dB at 315Hz. Note that the distance of 300m from the wind turbines is a close location.48. The paper in Audiology Today also states:
“Todd et al (2008) demonstrated that the resonant frequency of the human vestibular system is 100 Hz, concluding that the mechano- receptive hair cells of the vestibular structures of the inner ear are remarkably sensitive to low-frequency vibration and that this sensitivity to vibration exceeds that of the cochlea. Not only is 100 Hz the frequency of the peak response of the vestibular system to vibration, but it is also a frequency at which a substantial amount of acoustic energy is produced by wind turbines.”
49. In my opinion, this reference to the work of Todd (Todd et al., 2008) is merely repeating the errors and misrepresentations made by Pierpont in her use of Todd’s research. I repeat that Dr. Todd repudiated Pierpont’s use of his work (Todd, 2009); however, I cannot be sure that Dr. James is aware of this repudiation. The 100Hz maximum response of the vestibular system was elicited using head-borne vibration following vibratory stimulation at the mastoid bone. The response was detected by OVEMP potentials, not by any adverse effects on the subject.
50. To write that 100Hz “is also a frequency at which a substantial amount of acoustic energy is produced by wind turbines” and to link this with Todd’s work in inaccurate. In the Kamperman and James paper referred to above, they estimate that the sound level at 100Hz at a distance of 1000ft (which is a close siting) from a 2.5 MW turbine is about 45dB externally and 30dB internally, as in Fig. 3. I do not believe that many of Dr James’ fellow acousticians would call this “substantial” acoustic energy.
What are the facts?
51. There are widespread misunderstandings about infrasound and low frequency noise, especially in relation to wind turbines (Leventhall, 2006). Some of this misunderstanding arises from concentration on frequencies, whilst ignoring the overriding importance of levels. In addition, much of the earlier work on low frequency noise and infrasound was targeted towards tonal noises, which are the common environmental noise occurrences at these frequencies, although narrow band noise problems also occur, but less frequently.
52. The WHO “Community Noise” is often quoted as cautioning against low frequency noise, but one should also read its description of low frequency noise sources (Berglund et al., 2000).
“The evidence on low-frequency noise is sufficiently strong to warrant immediate concern. Various industrial sources emit continuous low- frequency noise (compressors, pumps, diesel engines, fans, public works); and large aircraft, heavy-duty vehicles and railway traffic produce intermittent low-frequency noise. Low-frequency noise may also produce vibrations and rattles as secondary effects. Health effects due to low-frequency components in noise are estimated to be more severe than for community noises in general (Berglund et al., 1996).
Since A-weighting underestimates the sound pressure level of noise with low-frequency components, a better assessment of health effects would be to use C-weighting.“
53. The first sentence of this quotation, from Section 3.9 of “Community Noise”, is often reproduced by objectors, but the sentence which follows is not. This second sentence tells us that environmental low frequency noise problems are generally tonal problems, that is “components”, which occur in continuous noise from machinery. It is notable that there is no mention of wind turbines as a low frequency noise problem in a paper with Scandinavian authors. Tonal noises are more annoying than broad band noises, which is why they are often given a penalty, typically 5dB, in their assessment. The German standard for assessment of low frequency noise is oriented to the audibility of tones and states, “Noise is considered to be especially discomforting if it has tonal components” (DIN:45680, 1997). The stress on tones is made clear in an earlier paper by authors whose work is the basis of the DIN 45680 Standard (Piorr and Wietlake, 1990).
54. A well known “hum” problem was in Kokomo, Indiana. After investigation, the problem was attributed to both an industrial fan at 36Hz and a large compressor with fundamental 10Hz and harmonics measured up to 100Hz (Cowan, 2003 ).
55. An audible noise is not necessarily an annoying noise. Fig. 3 is a model of perception, which is used here to illustrate the hearing process.
56. This simple model for considering human response to sound identifies three broad stages, Detection, Perception and Response (Leventhall, 1998).
1 – The input stimuli enter the detection mechanism, the ear, and are converted to signals for the brain.
2 – The stimuli are perceived in the brain as sounds, giving an indication of their frequencies and levels.
3 – Response, which is greatly influenced by emotions, follows from perception.
57. There is variability at all the stages, but the best quantified steps are detection and perception leading, for example, to the well known hearing contours and hearing thresholds. These may be determined without production of an emotional reaction in the subject. It is the response which displays the widest emotional variations where, for a given low level of unwanted sound, response may vary between, “I am not bothered by it” to, “it is ruining my life.” The response is clearly governed by personal and situational factors and particularly by the listener’s attitude to the noise source.
The importance of attitudes to noise as a determinant of the response
58. An “attitude” can be considered as a judgemental evaluation which has developed in a person’s mind. Attitudes are not necessarily fixed, but are subject to modification from both external and internal influences. It has been found that response to a noise is strongly determined by attitude to the noise and its source. An early investigation showed differences in responses to the same noises between two groups in whom there had deliberately been developed either a positive or a negative attitude to the source of noise (Jonsson and Sorensen, 1970). For example, it was shown for the same aircraft noise that, for groups of 80 – 90 persons, serious disturbance was found in 14% of the group with a positive attitude, 59% of the group with a negative attitude and 36% of those in the control group.
59. The importance of attitude has been confirmed by later work. For example:
“Variables that may modify reaction to noise, such as noise sensitivity and attitude to the noise source, account for more variation than does noise exposure” (Job, 1988).
60. Similar outcomes have been found in other studies. In particular, for transportation noises, it was concluded:
“Fear has a very large impact on annoyance. Persons who experience fear related to the transportation that causes the noise report higher annoyance compared to persons who do not experience such fear. With three categories, the difference between the lowest and the highest fear level is equivalent to a DNL difference of (at most) 19 dB. The effect of fear is found for all three modes of transportation, but it appears that only few persons associate high fear with railway traffic. It is not clear whether the relation of annoyance with fear depends on the actual experience of fear, or is due to a common predisposition to noise annoyance and fear. This point is of practical interest. If actual fear is a condition for the increase in annoyance, then communication that reduces the feelings of danger may also reduce noise annoyance.
However, there will be no effect of a reduction in the actual fear if a predisposition to experiencing fear is the cause of higher noise annoyance.” (Miedema and Vos, 1999).
61. What this work tells us that the level of a noise is not the most crucial factor, but that attitude towards, and fear of a source, are important. This is particularly so for sources which produce a relatively low level of noise, such as wind turbines. Fear and anxiety about a noise are very real beliefs to the person who holds them. They are not fabricated or made up in any way, but genuinely held, although their development may have been influenced by others.
62. Fear and anxiety cause stress, which in turn may lead to a range of stress related problems, including poor sleep quality. There is no evidence for direct physiological effects from the inaudible components of wind turbine noise. However, if a person has developed an antagonism to turbines, they will respond to the audible components in a manner which exceeds anticipated response to the level of the noise. There is clearly fear in the present case, partly fear of the unknown, expressed in the Appeal by words such as:
“Industrial wind turbines are known to cause a range of serious health effects in certain individuals.”
“A significant body of expert opinion, scientific information and literature supports the Appellant’s contention that industrial wind turbines located at the distances approved for this project are more likely than not to cause serious harm to human health.”
“These effects are more likely than not caused by exposure to infrasound and/or low frequency noise and/or audible noise and/or visual impact and/or shadow flicker produced by industrial wind turbines.”
63. The following quotation shows that the Appeal takes no account of the importance of attitudes to wind turbines:
“The effects of the project on human health will be serious. The effects on the health of participating landowners and/or other persons at these locations will be even more serious as they are exempted from all setback requirements without scientific or other justification.”
64. Antagonism to a wind turbine development often comes from two directions: 1. Inadequate communication by the developer. The effects of this are explored by Maris et al. (Maris et al., 2007). 2. Excessive communication from objector groups.
65. It is unfortunate that objector groups have sought to win allies by generating fear and anxiety about wind turbines. Insufficient attention has been given to the part played by these groups in leading to the present polarisation of views. Social groups are susceptible to implanted ideas, which grow and develop in receptive minds. These have been described as “memes”, by analogy with genes (Dawkins, 1989) (Brodie, 2009). I believe that there has been implantation of false ideas about wind turbine noise, with a consequence that we see today in the extreme reactions to it.
66. My own experience in helping people to cope with their sensitivity to noise has been that attitudes can be changed and desensitisation achieved (Leventhall et al., 2008) (Leventhall et al., 2009).
67. Fig. 4 is from an investigation into low frequency noise from aircraft ground operations, as perceived in residences outside the airport. The light green area, marked Detectable, shows the range of perception between just audible and just annoying/objectionable. Clearly, frequent but intermittent noise from aircraft is not the same as noise from wind turbines, but the principle that a detectable noise need not be annoying, holds for all noises, as is our daily experience. Wind turbines are not a special case. Indeed, Fig. 4 is developed from work which was not specific to any source (Nakamura and Tokita, 1981). The range between Inaudible and Annoying may not be the same for wind turbines, but a range will exist for unbiased listeners. Bias arises when listeners are anxious about a noise, as the onset of perception is then sufficient to cause an immediate negative response.
Will engaging in Kent Breeze Wind Farms in accordance with the REA cause serious harm to human health?
68. I have reviewed the Noise Assessment Report for the Kent Breeze Wind Farm dated May 14 2010 , prepared by Hatch, and the MOE Renewable Energy Approval dated November 10th 2010. The MOE document specifies the noise limits which must be achieved at receptor points at different wind speeds as follows (chart available in downloadable document)
69. The Noise Assessment Report shows that these limits will be achieved at all of the 293 locations investigated with the exception of one point, which is the participating receptor at 332 m from the nearest turbine. Here the level is 45.8dBA externally. In my opinion, the Kent Breeze Wind Farm will not cause serious harm to human health of a participating receptor.
70. All levels have been arrived at using internationally accepted prediction methods and a widely used software package. The input data is appropriate and where corrections are required, these have been made.
71. My opinion is that there is no reason to believe that the required levels will be exceeded. In my opinion, the Kent Breeze Wind Farm will not cause direct pathophysiological serious harm to the human health of the noise receptors set out in the Noise Assessment Report.
CONCLUSIONS
72. Although there is much supposition, there is no evidence that low levels of inaudible infrasound from wind turbines have any effect on the health of people.
73. The low frequency noise from wind turbines may become audible outside a residence, at frequencies above about 40Hz, for those closest to the wind turbine. Audibility, inside or outside, is not necessarily a problem.
74. The main noise from wind turbines is the higher frequency swish sound, when it occurs, typically in the range of 500Hz to 1000Hz, although it can be at higher or lower frequencies. This sound is caused by modulation of the aerodynamic noise from the blades and occurs under certain conditions, which are not yet fully understood, although understanding is developing rapidly.
75. An important determinant of the effects of the low levels of audible noise from wind turbines is the listener’s attitude to the source of the noise. These attitudes are subject to manipulation.
17 January 2011 Dr. Geoff Leventhall Consultant in Acoustics
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Comment
It is clear from Dr Leventhall’s paragraph 25 (reproduced below) that he was well aware in 2011 (when he wrote this statement for the Canadian Erikson court case) of the work by Kelley et al and NASA researchers in the 1980’s, which established that wind turbine generated infrasound and low frequency noise (which he refers to as “sound” ) from a single downwind bladed wind turbine directly caused the annoyance symptoms reported by the residents. These symptoms included the body vibrations, also reported by Dr Nina Pierpont (in the 1982 paper by Kelley et al the vibrations are explicitly mentioned).
Why has Dr Leventhall not referenced this groundbreaking and important body of work by Kelley et al, which resulted in dramatic changes to the design of wind turbines from downwind bladed to upwind bladed, in order to reduce the generation of those frequencies below 200 Hz, and subsequently those frequencies directly causing the annoyance symptoms, when he clearly knew about the research?
Why does he not mention the important finding by Kelley et al that the symptoms were felt or perceived at levels which were BELOW the thresholds of audibility at the different frequencies?
25. Swinbanks bases his statements on his understanding of the work carried out by NASA in the early 1980s, when experimental wind turbines became operational. Swinbanks proposes a penalty of 7-10dB on the normal hearing threshold, specifically for listening to wind turbines. This results from a misunderstanding of the NASA work, which was for the short and sharp pulses of sound which were generated by the, now discontinued, downwind turbines as a blade passed the tower.