In Windpark N33, locals have been complaining about buzzing sounds for quite some time. Tones were also measured on the four southern wind turbines. Opponents fear the harmful health effects of low-frequency noise (LFG) from wind turbines. Is that true or not? Because Windpark N33 is controversial and people who are inconvenienced by wind turbines and from low-frequency noise in general may be particularly interested in this topic, RTV Noord went to search for clues. Upfront Disclaimer: Scientists are not clear in their assessment.
RIVM Study at LFG and Windmills
Research begins at the National Institute for Public Health and the Environment (RIVM). Last year, RIVM published a literature review. It lists the scientific publications that address the health effects of wind turbine noise. Sound was considered in a broad sense and low-frequency sound. One of RIVM’s most important conclusions is: “Living near wind turbines or hearing wind turbine noise can lead to chronic discomfort for residents. There is no consistent evidence of other health effects such as insomnia, sleep disturbances, and mental health effects.
RIVM adds that there are no indications that the effects of the low-frequency sound differ from the normal sound. It is also not expected that the effects of infrasound (the sound below twenty hertz to which our hearing is insensitive) will be different.
Annoyance can cause stress.
Fritz van den Berg, one of the researchers, sees it as a nuisance to people who live around wind farms. “This can cause stress. This is not healthy. This stress, in turn, can cause high blood pressure and increase the risk of, for example, a heart attack.” According to him, the scientific literature shows that such complaints can occur near wind farms. “But it’s also about other things,” Van den Berg says emphatically.
You often see that the stress and the complaints associated with it are also caused by the complex process surrounding building a wind farm, a negative change in the landscape and the fact that locals don’t feel heard. According to van den Berg, this is fundamentally different from the fact that low frequency noise causes complaints.
For people with low-frequency noise, this can be difficult to tolerate. They suffer a lot of inconvenience and are afraid of harm to health. For this reason, Tegenwind N33 and Platform Storm, for example, have joined forces to establish the Wind Turbine Disease Foundation.
Read this animation below about what a low-frequency sound is. Animation was created by Sander Schieving.
People who fight the health damage caused by wind turbine noise (and against low-frequency noise in general) often refer to Portuguese researcher Mariana Alves Pereira. It researches the effects of low frequency and infrasound on human and animal health. They focus mainly on frequencies below 20 Hz, which is a sound that our hearing is completely unaffected by. Alves Pereira referred to this sound as “a signature of windmills”. Van den Berg also mentions its existence.
Based on concrete examples, Alves Pereira tries to demonstrate a connection between this infrasound and the development of damage to the heart and blood vessels, especially if someone has been exposed to sound for a prolonged period.
Alves Pereira, along with other researchers, came to this path by searching among aircraft technicians. These people are constantly exposed to loud, low-frequency noise from aircraft while they are working. Relationships have been found between long-term exposure and health damage.
Alves Pereira and colleagues apply these research findings to people who live near wind turbines and where there are health harms as well. But these follow-up studies are controversial. Many scholars and experts criticize him. Because the noise from wind turbines is not as loud as aircraft noise. Additionally, according to critics, the examples used by Alves Pereira are eclectic and low in number. Also, any other causes that could explain the health damage have not been examined.
For this reason, Elvis Pereira is rarely cited by other scholars. There is even a scientific study entirely devoted to the methodology applied by Elvis Pereira and her colleagues. One of the conclusions of this research is that the modus operandi of Elvis Pereira is “an obnoxious quality.”
People who are bothered by windmills and low-frequency noise can’t do much with conclusions like these. They encounter problems and want to identify a cause, so that a solution can be found. On the contrary, they believe that Alves Pereira deserves recognition because they make it possible to discuss the consequences of low-frequency noise upstream.
Search for atrial fibrillation
Alves Pereira and her colleagues did not study the relationship between wind turbine noise and health damage. A study was also conducted in Denmark on the health effects of wind turbine noise. This mainly looked at atrial fibrillation. In atrial fibrillation, the heart beats irregularly and is usually faster than normal. It can cause feelings of restlessness and anxiety. Atrial fibrillation makes people more tired or dizzy while exercising.
A sample of more than 24,000 Danish nurses examined whether exposure to wind turbine noise causes atrial fibrillation. Researchers cautiously state that as the noise level increases, there is an increased risk of developing atrial fibrillation. But they add an important nuance, which is that chance cannot be ruled out. Thus, the scientific evidence has not been conclusively proven.
According to the World Health Organization (WHO), there is a risk of health damage above certain levels of noise. If the noise level is high enough, it may lead to complaints in the heart. In this case, it is about ambient noise in general, which is caused by, for example, traffic, in which all sound frequencies are included. This is not limited to low frequency noise only, nor is it specifically related to noise from the wind turbine.
Jan de Lat search
Leiden University Medical Center (LUMC) also conducts research on windmill noise, under the direction of clinical physicist and audiologist Jean de Lat. Like RIVM, LUMC serves as an overview of the various studies in wind turbine noise and health impacts. Final results are expected within two months. De Latt doesn’t want to say much about the results, but he’ll definitely lift a party veil. For example, he has seen studies appear where both people in noisy places and people in silent hideouts have been screened. It turns out that some people in the silent bunkers say they see the sound after all.
Sound standards are too high?
De Laat thinks noise standards in the Netherlands are too high. In the current situation, the noise standards are 41 dB. “If the noise standards were 35dB, you’d see complaints about wind turbines diminish.” At 41 dB, more than four times the noise is allowed.
Fritz van den Berg understands the De Lat series of ideas, but believes that scholars should not replace politics. “How high are the noise standards is a political question. Ultimately, wind turbines are also essential for the transmission of energy. You can make the standards tighter, but that will drastically reduce the number of places where wind turbines can still be built.”
Ultimately, according to van den Berg, the harmful effects of wind turbines must always be weighed against their advantages. “It is an illusion that all kinds of government decisions cause an inconvenience to anyone. You always weigh what is an acceptable nuisance. And where this limit should be is not due to science, but to politics.”
In principle, Delat agrees. His study shows that in a number of countries, including Germany, turbines must be at least ten times the height of their tip (mill height including blades) than the construction area. So if the height of the limb is 200 meters, then the distance to the construction area should not be less than 2000 meters. “At this distance, the noise of the mill does not exceed 35 decibels at night.”
dB (A), a unit of measurement for measuring noise pollution
The nuisance noise law applies the noise standard expressed in dB (A). Decibel means decibel, a unit of sound measurement. (A) Represents the correction applied. Because not all sound frequencies, including the low ones, can be perceived by people well. Low-frequency sound is sound with a frequency of less than 100 Hz. The lower the frequency, the louder the sound must be for him to perceive it. On onlinetonegenerator.com you can listen to the low tones you can hear yourself.
In Windpark N33, tones between 40 and 50 Hz are found. Since low-frequency sound is more difficult to perceive for most people of medium and high frequencies, this means that at dB (A) the low-frequency sound frequencies are much less important. So there is criticism of the official noise standard in the Netherlands, which does not take into account low frequency noise.