With the Australian government continuing its inquiries into whether infrasound from wind farms has an effect on human health, including earmarking $615,000 for a part-time commissioner to listen to complaints, one could be forgiven for thinking that infrasound may be a serious public health issue.
But does infrasound from wind farms actually have any effect on humans?
Infrasound is very low frequency sound, generated by everything from waves at the beach and the human body, right through to man-made infrasound sources like air conditioning units and road traffic. In most circumstances it is inaudible to humans, but some claim that infrasound created by the movement of wind turbine blades causes a range of negative health effects.
Experts such as Professor Simon Chapman say such concerns and reported effects about low-frequency noise from wind farms are in fact caused by the nocebo effect – a negative reaction to an innocuous substance because you’re expecting it to harm you. It’s the opposite to a placebo effect, and can similarly be very potent.
The nocebo effect hypothesis has just been given additional weight by recent research conducted by Renzo Tonin, Managing Director of Renzo Tonin & Associates, James Brett of the University of NSW and Ben Colagiuri of the University of Sydney.
In a paper recently accepted to the Journal of Low Frequency Noise & Vibration, the authors conducted a study to determine whether effects from wind-farm infrasound are caused by the infrasound itself, or by the nocebo effect.
The researchers measured the responses of groups of volunteers who either had high or low expectations about the likelihood they would experience negative effects from the noise. Volunteers wore custom-built headphones emitting simulated wind turbine infrasound, and reported back on their reactions following 10 minutes of either infrasound or a sham noise.
The authors found that the presence of infrasound in the experiment did not increase the number or intensity of the symptoms typically reported in connection with complaints about infrasound from wind farms. The paper concludes that:
“Were infrasound to have an effect one would expect to see an increase in symptoms when the infrasound was present, but that did not occur.”
“[V]olunteers who came into the experiment with pre-conceived notions of infrasound being harmful generally reported more symptoms than volunteers who began the experiment more sceptical about the potential health impacts of infrasound. These results support the hypothesis that a nocebo effect and not a direct physiological effect may be the cause of reported symptoms, at least for the time of exposure used in this experiment.”
The full paper will be published in 2016. A follow-up study is also being planned by James Brett and Renzo Tonin, on a question that arose out of the research: at what level does infrasound become audible?
Check back here for updates.
Comentarios