The so-called 'silent sound' that emanates from wind farms does not harm human health, a world-first study by Woolcock researchers has confirmed.
The important new research found no evidence for the existence of wind turbine syndrome, a condition that some believe impacts those living near wind farms and is caused by the below human hearing noise called infrasound.
"We've been able to show conclusively that the infrasound generated by wind turbines doesn't make you dizzy or nauseous, doesn't impact heart health or mental health, or impact on sleep," says lead study investigator Associate Professor Nathaniel Marshall. "Uncertainty around the syndrome has cast a shadow over the future of wind farms as a clean energy source, so it's great to get such a clear result from the study."
The research was published this week in the international journal Environmental Health Perspectives.
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Australia is home to more than 100 wind farms housing more than 2,800 turbines. The largest is Cooper's Gap Wind Farm in Queensland, followed by Macarther Wind Farm in Victoria and Snowtown Wind Farm in South Australia. As the cheapest source of large-scale renewable energy, wind power use is rapidly expanding in Australia, with multiple new projects in the pipeline.
But with the growth has come a rise in concern from residents living nearby who report experiencing headaches, dizziness and sleep disturbances which they attribute to the turbines. The symptoms, which also include nausea, tinnitus and irritability, are referred to collectively as wind turbine syndrome, a medical state that many, including some scholars, believe exists.
Our researchers tested the presence of the syndrome in the laboratory using an innovative custom audio system designed by acoustic engineer Dr Renzo Tonin.
"The infrasound generated by the audio system matches the audio pattern recorded from working wind turbines, and is replayed at a conservatively high level corresponding to a wind turbine being only 390m away," Dr Tonin says.
The researchers enlisted 37 healthy 'noise sensitive' adults to carry out three 3-night stays in the sound-proof Woolcock sleep lab. Participants were exposed to either wind turbine simulated infrasound, no sound or traffic noise. They were 'blinded' as to whether infrasound or no sound was being played as infrasound is inaudible.
Testing was carried out to monitor the volunteers’ sleep quality and duration, brain activity, symptoms, cardiovascular changes and neurobehavioral performance.
"None of the people exposed to infrasound developed what could be described as wind turbine syndrome," Associate Professor Marshall says. "There was no impact on sleep, brain functioning or cardiovascular or psychological health, so we think it's really improbable that wind turbine infrasound causes ill-health or sleep disruption."
The findings are consistent with the theory that wind turbine syndrome is caused by nocebo effects, that is, a person's belief that the exposure will do them harm.
"That's why it's critical these results are shared far and wide Associate Professor Marshall says. "We hope that such strong findings resulting from really robust research will help reassure people living near wind farms that the exposure is not impacting on their health in any measurable way."
The comprehensive experiment was funded over five years by the NHMRC. Results will be used by policymakers to inform public health and manage future growth of the clean energy source.