“Health effects due to low-frequency components in noise are estimated to be more severe than for community noises in general” - World Health Organization [1]

Wind turbines generate a broad spectrum of noise including low frequency noise (LFN). [2]

A Canadian and American Wind Energy Association sponsored report denies adverse health effects from wind turbines but do acknowledge that LFN emitted by spinning wind turbines could possibly be annoying to some.[3]

This position appears to understate the potential adverse effects of LFN induced annoyance.

Geoff Leventhall one of the authors of the Canadian and American Wind Energy Association sponsored report acknowledges the serious nature of low frequency noise induced annoyance by asserting

“The claim that their "lives have been ruined" by the noise is not an exaggeration…”[4]

A more comprehensive discussion of annoyance resulting from LFN states:

“Research conducted by Lindberg and Backteman (1988) found that LFN contributes to annoyance responses by

• creating a sensation of pressure in the ear,

• periodically masking effects on medium to high frequency sound with a strong modulation effect that can disturb normal conversation, and

• by creating secondary vibrating effects typically experienced within homes.

In addition, Berglund and Lindvall (1995) documented a number of potential behavioural dysfunctions associated with LFN, such as

• task performance deterioration,

• reduced wakefulness, and

• sleep disturbance, headaches, and irritation

It has also been learnt that LFN does not need to be considered “loud” for it to cause such forms of annoyance and irritation…In fact, LFN is found to be more difficult to ignore than higher frequency noise, and sufferers describe it as

• omnipresent,

• impossible to ignore,

• worse indoors (due to the effects of vibration),

• impossible to locate, and

• difficult to tune out.

Unlike higher frequency noise issues, LFN is very difficult to suppress. Closing doors and windows in an attempt to diminish the effects sometimes makes it worse because of the propagation characteristics and the low-pass filtering effect of structures.

Individuals often become irrational and anxious as attempts to control LFN fail, serving only to increase the individual’s awareness of the noise, accelerating the above symptoms.” [5]

Authoritative health organizations acknowledge that LFN noise is a potential health risk to humans. [6],[7]

The logical mitigation technique would be to increase wind turbine setbacks as LFN

“components may travel further than the higher frequency components. Since low-frequency noise is particularly annoying to most people, it is important to specify limits for low frequency noise.” [8]

Further study of the effects of wind turbine LFN is required to assist in the development specific guidelines to mitigate the potential health risks. [9],[10],[11],[12]

In November 2009 Japan is reported to have announced a four year health study on the adverse effects of wind turbine LFN.[13]