Short answer
Wind turbines generate infrasound, just like many other natural and human-made sound sources. Infrasound is very low-frequency sound, below the range that humans can normally hear. The key question is not whether infrasound exists, but whether the levels reaching homes are high enough to affect health.
Overall, major evidence reviews and assessments by public authorities show that infrasound from wind turbines at residential locations is normally below the human hearing and perception threshold. There is therefore no scientific support that infrasound from wind turbines, at the levels that occur when current guideline values are met, causes serious health effects. However, audible wind turbine sound can be experienced as disturbing, and annoyance and concern need to be taken seriously in planning, dialogue and follow-up.
Why is this discussed?
Infrasound causes concern because it is often described as “invisible” or “inaudible” sound that could still affect the body. It is understandable that people react to such claims. The sound environment affects everyday life, and for someone living near a planned wind farm, questions about sleep, health and safety can become very concrete. At the same time, several different issues are often mixed together in the debate: audible wind turbine sound, low-frequency sound, infrasound, vibrations, shadows, aviation warning lights and concern about changes in the local environment. This makes the issue difficult to discuss factually. Research shows that people can be annoyed by wind turbine sound, especially when the sound is audible and perceived as recurring or intrusive. But that is not the same as saying that inaudible infrasound from wind turbines has been shown to cause illness.
Common misconceptions
“Wind turbines spread dangerous infrasound that makes people ill”
Wind turbines do generate infrasound, but measured levels at homes are normally below the human hearing and perception threshold. Research therefore does not support the conclusion that infrasound from wind turbines causes serious health effects at normal exposure levels. At the same time, people’s concerns and experiences are important and should be taken seriously, since wind power can be perceived as disturbing even when research does not show health risks linked to the infrasound itself.
“If the sound cannot be heard, it may be especially dangerous because the body is affected without us noticing”
Several research groups have examined this specific question. Large population studies, including in Canada, have not found links between wind turbine sound and objectively measured sleep, blood pressure or stress. Laboratory studies in which participants were exposed to simulated wind turbine infrasound have also not been able to show that the infrasound causes the symptoms sometimes attributed to it. At the same time, research continues and public authorities follow the development of knowledge.
What do the facts say?
Wind turbines generate infrasound
Infrasound is sound below about 20 Hz. Wind turbines produce infrasound, but so do natural sources such as wind and waves, as well as many technical installations. The fact that infrasound can be measured does not automatically mean that humans can perceive it or that it affects health. The Swedish Environmental Protection Agency also assesses that there is no support for wind turbine noise, when current guideline values are met, causing other more serious health effects. Research on sound, sleep, perceived annoyance and new generations of wind turbines continues, which is important for further strengthening the knowledge base.
Measured levels are normally below the hearing threshold
Several research reviews and authority reports show that infrasound from wind turbines at homes is normally below the human hearing and perception threshold. A recent Swedish study has presented higher calculated levels of infrasound from modern wind turbines than have often been reported previously. At the same time, several authorities and research reviews assess that there is still no scientific support that the levels reaching homes cause serious health effects. Research in this field therefore continues to develop.
Audible sound and perceived annoyance matter more than infrasound
The most consistent conclusion in the research is that some people can experience wind turbine sound as annoying. This experience is influenced not only by sound levels, but also by factors such as landscape change, trust in the process and how involved people feel. However, research does not show a clear link between infrasound from wind turbines and serious health effects.
What affects the assessment?
- Sound level at homes: The relevant level is the sound where people live and spend time, not the sound right next to the turbine.
- Distance, terrain and weather: Sound spreads differently depending on distance, ground conditions, wind and topography.
- Audible sound and low-frequency sound: What is mainly perceived as disturbing is usually the audible sound, not the inaudible infrasound.
- Perceived annoyance: Factors such as concern, trust, participation and visible changes in the landscape can affect how sound is experienced.
- Planning and follow-up: Careful sound calculations, control measurements and the possibility of taking action are important parts of responsible project development.
Conclusion
Wind turbines emit infrasound, but the overall body of research shows that levels at homes are normally below the human hearing and perception threshold, and that there is no scientific support that such infrasound causes serious health effects. At the same time, wind power can be experienced as disturbing by some people, and those concerns should be taken seriously through careful planning, dialogue and follow-up. It is also important that research continues to strengthen knowledge about sound, sleep and future wind turbines.
