Two noise surveys from Europe are frequently cited by energy industry defenders as evidence that there are no ill health effects found in people living near industrial wind turbines. The applicability of these surveys to most proposed and recently built facilities, however, is very limited. And in fact, their findings of significant annoyance at low sound levels and small relatively turbines suggest reason for concern. Annoyance from noise, by the way, is an adverse health effect, according to the World Health Organization (“Guidelines for Community Noise”, 1999), as is disturbed sleep, which can lead to many physical and psychological symptoms.
The survey from Sweden is: Pedersen and Persson Waye, 2007, “Wind turbine noise, annoyance and self-reported health and wellbeing in different living environments”, Occupational and Environmental Medicine 64 (7): 480-486. The survey from the Netherlands is: Van den Berg, Pedersen, Bouma, and Bakker, Project WINDFARMperception, 2008, “Visual and acoustic impact of wind turbine farms on residents”, FP6-2005-Science-and-Society-20 project no. 044628. Nina Pierpont provides a medical critique of the latter study on pages 111-118 of her book Wind Turbine Syndrome. Note that none of the survey authors are physicians, and neither the design of nor the conclusions from the surveys are reliable medically.
Here, I will simply describe what these surveys found and why they are not very relevant to current debates about wind turbine siting near homes. The general aim is to minimize the increase of noise, especially at night inside people’s bedrooms. The World Health Organization says that the noise level at night inside a bedroom should not exceed 30 dB(A) and that to ensure that level, the noise 1 meter away from the house should not exceed 45 dB(A). Ontario requires that the noise level 30 meters from the house should not exceed 40 dB(A).
In the Swedish survey (Pedersen and Persson Waye, 2007), the average sound level estimated at the respondents’ homes was 33.4 ± 3.0 dBA. The average distance from the turbines was 780 ± 233 m (2,559 ± 764 ft), and facilities of turbines down to 500 kW in size were included.
In the Dutch survey (Van den Berg et al., 2008), only 26% of the turbines were 1.5 MW or above, and 66% of them were smaller than 1 MW. Only 9% of the respondents lived with an estimated noise level from the turbines of more than 45 dB.
With such little exposure to potentially disturbing noise, it would be surprising indeed to find much health effect. And just so are they quoted. For example, from Pedersen and Persson Waye: “A-weighted SPL [sound pressure level] was not correlated to any of the health factors or factors of wellbeing asked for in the questionnaire”; “In our study no adverse health effects other than annoyance could be directly connected to wind turbine noise”.
But note that they did find a substantial level of annoyance, especially in rural areas and hilly terrain, and, as they note, “Annoyance is an adverse heath effect.” And: “Annoyance was further associated with lowered sleep quality and negative emotions. This, together with reduced restoration possibilities may adversely affect health.”
And from Van den Berg et al.: “There is no indication that the sound from wind turbines had an effect on respondents’ health …”.
The elided part of the sentence is: “except for the interruption of sleep”.
Again, they found a substantial level of sleep disturbance and annoyance. They note: “From this study it cannot be concluded whether these health effects are caused by annoyance or vice versa or whether both are related to another factor” (such as low-frequency noise). In other words, the data are inadequate for making any statement regarding health effects (and remember, annoyance, along with interruption of sleep, is a health effect). “Annoyance with wind turbine noise was associated with psychological distress, stress, difficulties to fall asleep and sleep interruption.” “From this and previous studies it appears that sound from wind turbines is relatively annoying: at the same sound level it causes more annoyance than sound from air or road traffic.”
In conclusion, even in the low-impact situations surveyed in these studies (small turbines, setbacks large enough to ensure low A-weighted noise levels), health effects, particularly due to annoyance and sleep disturbance, were seen. With larger turbines and facilities and smaller setbacks from homes, adverse health effects would clearly be expected to affect more people and to a greater degree.