WIND TURBINES, NOISE AND HEALTH EFFECTS.

 

I first became aware that people were suffering from the effects of noise from wind turbines about twelve months ago when a friend casually told me in passing about the plight of a poor lady who lives near some wind turbines in Cornwall.

After learning about this lady's plight I undertook a literature search on wind turbines, noise and vibration, with particular reference to low frequency noise which is a major emission from turbines. What I discovered was that very little specific research has been done regarding the effects that wind turbines have on their neighbours. The information given by the wind power companies blatantly ignores the fact of low frequency noise and deny that any significant noise is produced from turbine blades and motors. Information from abroad inc USA, Denmark, Holland, Sweden and Italy does indeed suggest that there are significant noise issues surrounding wind turbine developments. It is also recognised that due to the characteristics of the noise produced by turbines, it is not easily masked by background noise.

With ever increasing emphasis being placed on renewable energy, we must balance our natural desire to save the planet today by fully weighing up the risks of available resources against possible benefits. And we must look at the effects that they have on our health and our countryside carefully.

Electricity generation from wind seems to be the current mainstay for the present Government's policy on renewable energy generation. However, little research has been carried out regarding the problems of low frequency noise and its effects on the neighbours of these structures. In fact, current recommendations for noise evaluation (ETSU-R-97) near wind turbine sites completely exclude the measurement of low frequency sound. The wind turbine companies state that the wind turbines at 350 m will only produce noise which is equivalent to that in a quiet room, (35-45dB) however the sound measurement scale which they are using ( A weighting) completely ignores the low frequency components. A preferred method of noise measurement would take the whole range of frequencies into consideration by using for example a C weighting scale. In addition to this the fact that wind turbines are situated in places where the background noise levels are low ( typically 30 dBs or less), therefore any noise produced will have a greater effect on inhabitants of nearby dwellings

Low frequency sound is often beyond the audible range i.e. you can't hear it, but you can feel it as a resonance, typically in the chest or through the feet etc.

This problem has been recognised by the World Health Organisation who has said that special attention should be given to noises in an environment with low background sound levels, where there are combinations of noise and vibrations; and where there are noises with low frequency components. They recognise that low frequency noise can disturb rest and sleep even at low sound levels. More importantly the WHO states that in noises where a large proportion is in the low frequency range, the adverse effects on health may be considerably increased. As a result of these findings they feel that the evidence available on low frequency noise is sufficiently strong to warrant concern. They go further and suggest that for noise with a large proportion of low frequency sounds, lower acceptable levels should be accepted (i.e. lower than 30dB). Sadly the UK is lagging behind the rest of Europe in taking these factors into consideration. But there is no getting away from the fact that low frequency noise causes extreme distress to a number of people who are sensitive to its effects.

DEFRA (Department for the Environment, Food and Rural Affairs) commissioned a review of published research on low frequency noise by Dr Geoff Leventhall, earlier this year. In this document low frequency noise was classified as a background stressor which leads to inadequate reserves of coping and may lead to chronic psychological and physiological damage.

Therefore the symptoms can range from headaches, migraines, nausea, dizziness, palpitations, and tinnitus to sleep disturbance, stress and anxiety and depression. These symptoms will have a knock on effect in daily lives, with poor concentration, daytime somnolence, irritability and inability to cope.

The effects of low frequency noise are extremely difficult to manage as often sufferers develop an enhanced susceptibility i.e. develop a heightened awareness to the noise after prolonged exposure.

 

 

With this in mind I decided to visit the lady I mentioned initially. On questioning both her and several of her neighbours I discovered that many people living near this Wind Turbine development in Cornwall were suffering greatly from the effects of noise and shadow flicker from the turbines. Following initial conversations I sent out questionnaires and have been able to collate the information which is as follows: The majority of the people answering the questionnaire were in the 45-60 age group (51%) ; there were 2 people over 60 (14%); 2 in the 18-30 (14%) age group ;and 3 in the 30-45 age group (21%).

9 out of the 14 responders are employed ( 64%) and 5 are retired (36%).

The distance from the turbines varied between 300m to 1 mile

13/14 (93%) people stated that their quality of life has been adversely affected since living next to the wind turbines.

 

13 out of the 14 (93%) are complaining of more headaches since living near the turbines.10 out of the 14 (71%) are experiencing sleep disturbances. ( one of those saying that their sleep was not disturbed, stated that they were unsure whether the strobe effect of the blades wakes them up, but they certainly prevented them from going back to sleep).

One suffers from palpitations when the wind is blowing in certain directions. Stress and anxiety is suffered by 10/14 (71%). Migraines occur in 5/14 (36%)

 

Another complaint which I encountered when talking to these neighbours of turbines is the effect of the rotating blades in the sunlight- this characteristically causes a strobe effect ( stroboscopic effects are a recognised trigger for epilepsy). Interestingly this effect is not only obtained by direct vision of the blades but also from the shadow flicker caused by the blades in the light . The people questioned stated that this was a cause of headaches, migraines, nausea, vertigo and disorientation in many residents and this effect occurs at considerable distances.

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I have found from my discussions with neighbours of turbines that sleep disruption is a major problem. This is borne out by research from the University of Groningen in the Netherlands, which shows that sound levels near a wind turbine park were up to 18dB higher at night when compared to daytime levels- The researchers felt that this discrepancy will be greater for taller turbines which is important to remember as the height of turbines is constantly increasing. (The gear box and gearing systems of the latest generation turbines are claimed to be quieter, however, the enormous blades increase noise levels as they swish through the air.) The reason for these increased sound levels at night is because of air cooling, reducing the wind speed close to the ground. However, the wind speed at hub height at night is higher than expected; therefore overall noise levels are increased.

 

With all the evidence available I feel that much more attention should be paid to health issues surrounding noise and shadow flicker. More detailed research is needed to explore these issues further. When sound measurements are being taken realistic measurement scales should be used taking into consideration low frequency sound (i.e. "C" weighting).

 

It is with these results in mind that, with the help of an acoustician, Dr David Manley, we are involved in active research establishing the degree of the significant noise problems suffered by neighbours of wind turbines.

From initial information I feel that insufficient consideration is given to ensure adequate distances between turbines and dwellings. It is only now that these issues are becoming apparent as neighbours of turbines are standing up and complaining about the noise and the cumulative health effects (i.e pending litigation in Barrow by neighbours of turbines).These noise, vibration and shadow flicker effects will increase as the turbines increase in size and their blade lengths double in length.

There can be no justification in allowing these industrial electricity-generating machines to be constructed near homes when adverse health effects have become evident to the general public.

 

 

REFERENCES

 

1) Frits van den Berg. Wind turbines at night: acoustical practice and sound research. Euronoise, Naples 2003.

 

2) E Pederson and K Persson Waye. Perception and annoyance of wind turbine noise on a flat landscape. Proceedings of Internoise 2002 Dearborn 2003.

 

3) GP van den Berg. "Not biting the hand that feeds you"... a plea for independent acoustical advisors. Gehird juli 2000 pp 103-105.

 

4) Berglund,B., Hassmen,P., and Job,RFS. Health Effects induced by low frequency noise: a critical review. Archives of the center for Sensory Research, 1994, 1(2), 1-39.

 

5) World Health Organisation. Guidelines for Community Noise, executive summary 3.10.

 

6) Berglund, B.,Lindvall,T.,Schwela,D.H.(eds) (1999): Guidelines for community noise- WHO, Geneva

 

7) Hendin R, Manley D; The Quiet Con- A weighted Leqs as the Index of Aircraft noise Annoyance. October 2003

 

8) L.Maffei, P.Lembo Dispama. Faculty of Architecture, Seconda Universita di Napoli. The impact of wind turbines in rural areas. Paper presented at Euronoise Conference 2003.

 

9) Eja Pederson, Hogskolan i Halmstad: Noise annoyance from turbines- a review. Natur vards Verket. Report 5308, August 2003

 

10) Persson Waye K, Bengtsson J, Kjellberg A, Benton S: Low frequency noise "pollution" interferes with performance: Noise Health . 2001;4(13):33-49

 

11) Hughes R, Jones DM: The Intrusiveness of sound: Laboratory findings and their implications for noise abatement. Noise Health. 2001;4(13):51-70

 

13) Schulte-Fortkamp B. Technical University of Berlin, Institute of Technical Acoustics, Sec TA7, Einsteinufer 25, 10587 Berlin, Germany. The meaning of annoyance in relation to the quality of acoustic environments. Noise Health. 2002;4(15):13-18

 

 

Dr Amanda Harry MBChB, PGDipENT