No Adverse Health Effect from Wind Turbines by Richard Komorowski
Cornwall ON – The scientific evidence does not demonstrate any direct causal link between wind turbine noise and adverse health effects, according to a new report from Dr. Arlene King, Ontario’s Chief Medical Officer of Health. The report, published today, was prepared by Dr. King, in consultation with the Ontario Agency for Health Protection and Promotion, the Ministry of Health and Long-Term Care, and the Council of Ontario Medical Officers of Health. It summarises the scientific evidence from reputable sources worldwide on the potential health impacts of wind turbines.
The review concludes that while some people living near wind turbines report symptoms such as dizziness, headaches, and sleep disturbance, the scientific evidence available to date does not demonstrate a direct causal link between wind turbine noise and adverse health effects. The sound level from wind turbines at common residential setbacks is not sufficient to cause hearing impairment or other direct health effects, although some people may find it annoying.
The major complaint about wind turbines is the noise they produce. Modern designs, however, minimise the noise, so that at an appropriate distance, the sound from a turbine is no more than 40 decibels (about the same as a quiet room). By contrast, it takes consistent sound levels in excess of 75 decibels to cause ear or other health problems. (Note: 50 db is ten times louder than 40 db, and 60 db is ten times louder than 50 db, and 100 times louder than 40 db).
This does not imply, however, that turbine noise is not sometimes annoying, but studies in the Netherlands and Sweden have shown that people who were against wind turbines on principle (e.g. their visual impact), tended to be more annoyed than people who were neutral in their reactions to turbines, and far more annoyed than those who saw them as a good thing.
Anti-wind advocates typically cite very low frequency sound (below the range of human hearing) as a problem. These low frequency sounds, however, are everywhere, from natural sources such as wind and water movement, and also road traffic, aircraft and ventilation systems. Vehicles are the worst offenders. Generally, it is impossible to tell if a low frequency sound is from a wind turbine or is just environmental background noise.
Sensitive people can find this low frequency sound annoying, and at a high enough volume, severe ear pain can arise. All the same, there is no evidence of adverse health effects from low frequency sound below 90 db. Studies show that wind turbines can produce from 50 to 70 db of these “infrasounds”, which is well below levels that cause concern.
Another potential health hazard mentioned by anti-wind advocates is “shadow flicker”, caused by shadows of rotating blades. Epileptics can be especially affected by this; however, the flicker frequency of a wind turbine is well below the frequencies that cause epileptic seizures.
Other possible hazards sometimes cited include ice thrown off the blades, and sometimes the blade itself breaking and being thrown a considerable distance (up to 500 metres). These incidents are extremely rare, however, and the minimum setbacks required by provincial legislation appear to provide an adequate safety margin.
The minimum setback for a wind turbine is 550 metres from a residence. The setbacks rise with the number of turbines and the sound level rating of the turbines. For example, a wind project with five turbines, each with a sound power level of 107dB, must have its turbines setback at a minimum 950 metres from the nearest residence.
Not everyone is satisfied with the report, and wind farm development remains controversial. Wind Concerns Ontario is a province-wide advocacy organization “whose mission is to protect the health, safety and quality of life of the people of Ontario from industrial wind turbines.”
According to their mission statement, “Wind Concerns Ontario provides a strong, unified voice of opposition to the unchecked rush of locating thousands of massive industrial wind turbines across the province which are too close to human habitation and are without the benefit of full environmental assessment.”
In a statement posted on their website, Wind Concerns Ontario criticises the report, claiming that the Ministry of Health or local public health units have, contrary to legislation, failed to investigate the claims of those who say their health is suffering from being too close to windmills. According to the statement, “Every single person who has gone to their local Public Health unit has been told there is nothing they can do, are sent elsewhere, are told it is beyond their scope of responsibility and they cannot investigate.”
In addition, they state that provincial report was lifted, almost word for word, from a CanWEA [industry sponsored] report.
The following are the main conclusions of the provincial report on the health impacts of wind turbines:
- While some people living near wind turbines report symptoms such as dizziness, headaches, and sleep disturbance, the scientific evidence available to date does not demonstrate a direct causal link between wind turbine noise and adverse health effects.
- The sound level from wind turbines at common residential setbacks is not sufficient to cause hearing impairment or other direct adverse health effects. However, some people might find it annoying. It has been suggested that annoyance may be a reaction to the characteristic “swishing” or fluctuating nature of wind turbine sound rather than to the intensity of sound.
- Low frequency sound and infrasound from current turbines are well below the pressure sound levels at which known health effects occur. Further, there is no scientific evidence to date that vibration from low frequency wind turbine noise causes adverse health effects.
Despite these conclusions, the verdict about whether large scale wind farms are safe seems to be still open. While there seem to be no direct safety concerns that cannot be addressed by having an adequate setback (e.g. falling windmills), the problems of a minority of people, living in the vicinity of these wind farms, and claiming poor health as a result, do not seem adequately addressed. Are these health problems (including heart palpitations, stomach problems, sleep deprivation and cognitive problems) actually directly caused by the wind turbines, or are they caused by anxiety about the turbines?
The provincial government report itself states:
- Community engagement at the outset of planning for wind turbines is important and may alleviate health concerns about wind farms.
- Concerns about fairness and equity may also influence attitudes towards wind farms and allegations about effects on health. These factors deserve greater attention in future developments.
Are large scale wind farms truly safe in all aspects, or do we need further regulation in order to protect the minority of residents who may indeed be suffering?
Ministry of Health Study:
Wind Concerns Ontario:
Canadian Wind Energy Association (CanWEA):