Science, Art, Litt, Science based Art & Science Communication
Wind turbines are a source of clean renewable energy, but some people who live nearby describe the shadow flicker, the audible sounds and the subaudible sound pressure levels as "annoying." They claim this nuisance negatively impacts their quality of life.
The low-frequency, inaudible sounds made by wind power stations are not damaging to human health despite widespread fears that they cause unpleasant symptoms, according to research published in Finland on 22nd June, 2020.
A number of studies have already concluded that the audible noise from the energy-generating windmills does not cause health impacts beyond annoyance and sleep disturbance in people living close by.
However, the two-year Finnish project, commissioned by the government, examined the impact of low-frequency—or infrasound—emissions which cannot be picked up by the human ear.
People in many countries have blamed the infrasound waves for symptoms ranging from headaches and nausea to tinnitus and cardiovascular problems, researchers said.
Scientists used interviews, sound recordings and laboratory tests to explore possible health effects on people living within 20 kilometres (12 miles) of the generators.
Yet the findings "do not support the hypothesis that infrasound is the element in turbine sound that causes annoyance," researchers said, adding: "It is more likely that these symptoms are triggered by other factors such as symptom expectancy."
Tests also found no evidence that wind turbine sounds affected heart rates, the study said.
Also , earlier a team of researchers from the University of Toronto and Ramboll, an engineering company funding the work, set out to investigate how residential distance from the wind turbines—within a range of 600 meters (1,968.5 feet) to 10 kilometers (6.2 miles)—affects people's health.
They reanalyzed data collected for the "Community Noise and Health Study" from May to September 2013 by Statistics Canada, the national statistical office. The team reports their new analysis in the Journal of the Acoustical Society of America*.
Respondents who live in areas with higher levels of modeled sound values (40 to 46 decibels) reported more annoyance than respondents in areas with lower levels of modeled sound values (<25 dB). Unsurprisingly, the survey's respondents who live closer to the turbines "were more likely to report being annoyed than respondents who live further away."
The earlier Statistics Canada study found no direct link between residents' distance from wind turbines and sleep disturbances (as measured by sleep assessments and the Pittsburgh Sleep Quality Index), blood pressure, or stress (either self-reported or measured via hair cortisol). However, the more recent study showed that survey respondents closer to wind turbines reported lower ratings for their environmental quality of life. Barry and her co-authors note that their cross-sectional study cannot distinguish whether these respondents were dissatisfied before the wind turbines were installed.
Wind turbines might have been placed in locations where residents were already concerned about their environmental quality of life, according to researchers. Also, as is the case with all surveys, the respondents who chose to participate may have viewpoints or experiences that differ from those who chose not to participate. Survey respondents may have participated precisely to express their dissatisfaction, while those who did not participate might not have concerns about the turbines.
The team's more recent study didn't explicitly find evidence that exposure to wind turbines actually impacts human health.
* "Using residential proximity to wind turbines as an alternative exposure method to investigate the association between wind turbines and human health," Journal of the Acoustical Society of America (2018). DOI: 10.1121/1.5039840