Living close to a windfarm could damage your hearing, according to articles in today’s  Telegraph, Times,  Daily Mail and Express.

The Express said “Turbine buzz ‘is deafening'” and said scientists were warning that noise from windfarms might lead to deafness. The Telegraph took a similar line, beginning “Living close to wind farms may lead to severe hearing damage or even deafness”.

However, the research involved did not measure deafness, did not mimic wind turbines and did not show that windfarms cause hearing damage, according to the lead author of the study.

The research

Munich University’s Markus Drexl and colleagues looked at the impact of low-frequency sound on the inner ear. They exposed 21 young adults with normal hearing to a 90 second pulse of low frequency sound at 80 decibels.

Regular and sustained exposure to loud noise –   above 90-95 decibels – is known to cause hearing damage. Drexl’s experiment examined the effect of low frequency sound, which is less audible than the noise from a truck or pneumatic drill. The scientists wanted to know if this type of noise might also be damaging to the ear, even though it is not perceived to be loud.

After the short, low frequency pulse the researchers recorded faint noises that are naturally emitted from the inner ear. These faint noises are part of the normal activity of the human ear but are known to disappear in conjunction with hearing loss.

Drexl’s research detected changes in these faint noises that lasted for about two minutes after the low frequency pulse had finished.

Drexl tells Carbon Brief:

“These changes are definitely not normal and we don’t know what happens during longer exposures. You can at least speculate this might be a first indication of the start of a damaging process.”

So where do wind turbines come in? The research paper doesn’t mention wind – at all. However, a press summary written by the authors gives wind turbines as one example of sources of low frequency noise, along with ventilation and air conditioning systems.

Windfarm claim is not substantiated

Drexl says:

“There’s a very loose relationship between our work and wind turbines… If you mention low frequency noise people always seem to relate this to wind turbines.

“The noise we used was at the same frequency as some of the sounds turbines emit but we by no means mimicked the spectrum of sound they produce.”

He adds that the 80 decibel sound they used was probably louder than what people living near wind turbines would be exposed to. Drexl told the Telegraph the noise he used was comparable to the thumping sound you get when you open a car window while driving fast on a motorway.

However, he did tell the paper:

“We don’t know what happens if you are exposed for longer periods of time, [for example] if you live next to a wind turbine and listen to these sounds for months or years.”

Planning guidance requires that increases in noise associated with new windfarms be limited to 5 dB above background levels in the gardens of the nearest houses to the site. In quieter areas with low background noise, sound must be limited to 35-40 dB, with a fixed nighttime limit of 43 dB. For comparison, a noisy office would come in at around 60 dB – so a bit louder.

These rules apply to audible noise. We’re checking how they relate to low frequency sound that may be less audible. However, consultants SKM Enviros say that low frequency noise is associated with older turbine designs and that modern turbines produce “imperceptible” levels of this type of sound.

Drexl’s research also did not test the people experimented on to see if the noise they were exposed to had caused hearing damage, let alone deafness. It only looked at the faint ear noises for a few minutes after exposure and the research paper emphasises that the effects found might only be transient.

Drexl says the idea that he had shown wind turbine noise “is deafening” is incorrect.

“It’s definitely not what we’re saying in the paper. You cannot make this claim. It is not substantiated at the moment because we haven’t shown whether low frequency sound is causing any damage to the inner ear. I also don’t know of any cases of deafness being reported by people living near wind turbines.”

In summary, the work did not look at wind turbines and did not find any hearing damage.

So why has it been reported in some places as if it did? Some of the media have “over-interpreted” the research, Drexl says.