RE: Stacey Reid’s letter on noise and turbines (Vacuum is louder than a turbine, June 28).
Developers and our government will state that the maximum allowable limit of wind turbine noise is 40 decibels; however ministry guidelines allow the noise levels to increase from 40 dBa to 51 dBa under increased wind conditions.
A 10 decibel increase in noise is perceived as a doubling of sound to the human ear. Noise coming from wind turbines does not match the sound of a refrigerator or a quiet library as we so often hear. Under most circumstances loud noise is short term that will pass by, can be turned down or shut off.
With wind projects none of the above applies. The dynamics of living surrounded by multiple turbines cannot be compared to other community noises.
The noise is not only loud, it is cyclical in nature and there is no ability to turn it down or shut it off at two in the morning when families cannot sleep. The audible noise problem is compounded by the presence of low frequency noise. This is noise you cannot hear but you can feel. It penetrates walls.
This combination can keep people awake part of the night, or in some severe cases all night, on an ongoing basis. There is no reprieve and in some cases they have no choice but to abandon their home.
It is known that many of these wind projects are operating with noise levels that are out of compliance, exceeding even the maximum 51 dBa noise level allowed. The general public is unaware of this because the ministry has chosen to leave wind projects out of the traditional checks and balances that other industry must abide by.
Wind turbines and transformer stations must have a Certificate of Approval to operate. If they are operating out of compliance, there should be some record of contravention of the approval, but oddly there are no contraventions listed on the ministry’s annual reports from any wind developer even with documented exceedances in hand.
It is no wonder the public is confused. This provincial government is doing a grand job of it.
Barbara Ashbee, Orangeville
Stacey Reid’s letter (Vacuum is louder than a turbine, June 28) shows a misunderstanding of what a “dB” is and how it is measured, which leads to easy acceptance of the “noise, what noise?” position of wind farm proponents. A “dB” is a decibel — a measure of sound energy of any range — perhaps speech, bass speakers, vacuum cleaner noise or an earthquake. Our ears hear a only certain range of that energy — call it the “middle” range, including bagpipes, arguing couples and vacuum cleaners.
Community noise standards are based on sounds in the middle range, mainly because they are enforceable with inexpensive and easy-to-operate sound level meters. In sound measurement, this is called the “A” range and the measurements should read “dBA.”
Above and below that range, progressively, we hear little or nothing. Bats squeak in the “high” range. In the “low” range, we feel bass as well as hear it — it may nauseate us if it’s too loud.
Noise complaints about bass are more difficult to administer than sounds in the “A” range, as many communities have found, because they don’t necessarily show up on the sound meter.
But what about wind turbines? The majority of the noise they make is in the deepest “infrasonic” range, measured as “lin” — below bass, below hearing — and only measurable with expensive equipment by trained technicians. A study by NASA shows that the infrasonic part of the noise of turbines is about 55dB louder than the “A” part that a conventional meter would display.
So, if the meter reads 40dBA, the infrasonic noise can be 95dB. Although inaudible, this noise is experienced by the body in other ways that may be more akin to a continuous earthquake than to a refrigerator.
The doctors will have to weigh in on the health effects of these inaudible sound energies at strong levels over continuous periods of time, but the reference to community standards excludes the more relevant facts.
By comparison, although we can’t see the UV range of sunlight, we’ve learned the consequences of exposure and take precautions accordingly.
Dave Clark, Shelburne