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Editorials

Wind turbine noise

BMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e1527 (Published 08 March 2012) Cite this as: BMJ 2012;344:e1527

Rapid Response:

Re: Wind turbine noise

We thank Mr Barnard for his interest in our editorial and for at least appearing to agree with us that wind turbine noise causes annoyance.

Unfortunately, his ideas for "low cost solutions" will not be effective in reducing either "annoyance" or sleep disturbance. He seems incapable of recognising that, in this context, the term “annoyance” is used to denote a level of stress leading to harm, not just a mild irritation. Noise is universally recognised as a major public health problem causing not just sleep disruption with all its consequent effects including increases in blood pressure and myocardial infarction. The only effective measures are to reduce noise emission at source and/or attenuate the noise before it arrives at the receptor. For higher frequency noise, improved sound insulation of properties may be effective but the low frequency and infrasound emitted by wind turbines is not well attenuated and noise levels within a building may be higher than those outside. They can even be worse with the windows shut. Sadly therefore, Mr Barnard’s suggestions of thick blinds and closed windows will not be effective. Closed windows in summer either make the bedroom over warm or bring the need for air conditioning, neither of which may be conducive to good sleep.

Wind developers rely on increases in background noise with increased wind speed to mask turbine noise. Because of the low frequency content and impulsive nature of wind turbine noise, it is not masked by ambient noise and is audible 10-15dB below background. A white noise generator does not emit low frequency sound and therefore is useless in this range. If it is employed at sufficient intensities to mask other wind turbine noise frequencies, it will also impair sleep as is confirmed by a recent news report1.

Earplugs are uncomfortable, only suitable for short term use and would not be effective against low frequency and infra sound. Cognitive behavioural techniques have been suggested as a means of dealing with low frequency noise annoyance but are only effective when the source can not be identified (the hum). Wind turbines are all too obvious a source of noise.

All of Mr Barnard’s suggested measures would cause either distress or expense to those who find wind turbine noise thrust upon them. When secondhand smoke in public buildings was shown to inflict harm on non-smokers, the solution was to remove the source. No one, instead, seriously suggested impinging on the rights of non-smokers by forcing them to purchase respirators or nosegays to hide the smell. Factories are not permitted with noise emissions which are certain to impair the sleep of local inhabitants., We know of no good reason why wind turbines should not be subject to the same regulation. It is simply not good enough to exhort people to close their windows and wear ear plugs.

All governments seek to limit noise from all sources and we see no reason why wind energy should be exempt. We make no judgement about the value or otherwise of this form of electricity generation. If governments decree that the need to implement wind energy is so urgent that public health constraints can be overridden then appropriate compensation for those harmed must be put in place. We have no “agenda” save a desire to see that this public health problem is properly investigated and appropriate setback distances determined.

1. Fairfield residents given noise generators to drown out sound of windmills. Jul 16, 2012. http://www.wktv.com/news/local/Fairfield-residents-given-noise-generator...

Competing interests: None beyond those given with the editorial

25 July 2012
Christopher D Hanning
Honorary Consultant in Sleep Medicine
Alun Evans
University Hospitals of Leicester
Leicester LE5 4PW