2010.04.20

Subsequently Cooperate with a Study on the Effects of Low-Frequency Sounds on People

Subsequently Cooperate with a Study on the Effects of Low-Frequency Sounds on People

Press released on April 20.

The Ministry of the Environment (MOE) issued a press release titled Investigation Results of Noise and Low-Frequency Sounds Generated by Wind Power Facilities (FY 2009) (Press Releases) on March 29 (*).
http://www.env.go.jp/press/press.php?serial=12319

The Ministry also announced that in FY 2010, MOE will implement detailed investigation and analysis of more domestic wind power plants, and in regard to the relationship between noise and low-frequency sounds from wind turbines and their effects on people, work on the elucidation of the actual situations.

We were, at JWPA, determined to subsequently cooperate with the study by MOE, such as performing on-off operation of wind turbines and their components, in addition to providing wind speed and power data required for on-site measurement in this investigation and study. The implementation of this investigation and study of more wind power plants makes it possible to judge whether a concern, such that low-frequency sounds from wind power generation might affect people, is appropriate or not.

(*) Investigation results clarified the following three points:
Some newspapers reported that low-frequency sounds from wind power turbines would affect public health. However, this announcement did not refer to results and facts regarding the link between low-frequency sounds and health hazards.

1. A study confirmed that ultralow-frequency sounds of 20 Hz or less are sufficiently small values in comparison with the sensitivity threshold at all four measurement points.
• The frequency components of 20 Hz or less are about 20 dB smaller (one-hundredth) than the sensitivity threshold (minimum level detectable by people) of ultralow-frequency sounds, which are sufficiently small values even if taking into account individual differences (5 to 10 dB).

2. Some cases indicated noise value changes in the audible sound domain considered to occur from wind turbines.
• At three measurement points, except Toyohashi City, the noise value changes in the audible sound domain were detected by the on-off operation of wind turbines.
• At measure points in Toyohashi City, the noise value changes in the audible sound domain were not detected by the on-off operation of the wind turbines.

3. As for these measurement results, further investigation and review is necessary.
• It is required to additionally remove the effect of wind noise because the wind noise produced by a noise meter (microphone) exposed to the wind causes a problem of increasing the measured value in a strong wind.
• As a characteristic frequency component is seen in the vicinity of wind turbines, it is necessary to identity this sound source.

[Attached reference materials]
< Reference 1> Basic information of noise and low-frequency sounds
< Reference 2> Outline of investigation methods for noise and low-frequency sounds

As for the press release text and reference materials, please see below:
50-17press100420.pdf

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