The author first became aware of the adverse health problems associated with infrasound many years ago in 1974, when an aero-engine manufacturer approached him to consider the problems that office personnel were experiencing close to engine test facilities. He had been conducting research into the active control of sound, and the question was posed as to whether active sound control could be used to address this problem. At that time, this research was in its infancy, and the scale of the problem clearly lay outside practical implementation. Five years later, however, the author was asked to address a related problem associated with the low-frequency noise of a 15,000SHP ground-based gas-turbine compressor installation, having a 40 foot high, 10 foot diameter exhaust stack. This problem was of a more tractable scale, and the author and his colleagues successfully reduced the low-frequency noise of the installation by over 12dB. He subsequently was requested to address a similar installation of significantly greater size and power, again with accurately predicted results.
As a consequence of this and subsequent work, the author has gained considerable experience of the disturbing effects of low-frequency noise and infrasound. So when he first became aware of the nature of adverse health reports from windfarm residents, they were immediately recognisable as effects with which he had been familiar for as many as 35 years.
Since late 2009, the author has lived part-time within a Michigan community where windturbines have been increasingly deployed. Consequently he has had significant interaction with residents whose lives and well-being have been damaged, and moreover has experienced the associated very severe effects directly, at first hand. His resultant perspective is thus based on both detailed theoretical analysis, and extensive personal, practical experience.
It has been shown that upwind-rotor turbines can indeed sometimes give rise to impulsive low-frequency infrasound – a characteristic commonly attributed only to old-fashioned downwind rotor configurations. But perception of wind turbine low frequency noise and infrasound can be quickly suppressed by the effects of wind-induced airflow over the ears, with the result that incorrect conclusions can easily result from observations made when exposed to outside breezy conditions. The effects within a residence are much more readily perceptible, and cannot be ignored. An account has been given of an occurrence of severe direct health effects experienced by the author, and considered to be due entirely to wind-turbine infrasound, yet manifest under superficially benign conditions where no such adverse effects were anticipated.