(CN) – While wind turbines are a growing source of renewable energy, the audible sounds, subaudible sound pressure levels and shadow flicker they produce disturb some people who leave nearby.
In a report published Tuesday in the Journal of the Acoustical Society of America, a team of researchers presents its findings after reanalyzing data collected for the Community Noise and Health Study by Statistics Canada, the national statistical office. The earlier study investigated how living within 6.2 miles of a wind turbine affects a person’s health.
“The Community Noise and Health Study generated data useful for studying the relationship between wind turbine exposures and human health — including annoyance and sleep disturbances,” said Rebecca Barry, lead author of the new report.
“Their original results examined modeled wind turbine noise based on a variety of factors – source sound power, distance, topography and meteorology, among others.”
The results of the new study confirm Statistics Canada’s initial findings.
“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 (under 25 decibels),” said Barry, a teaching assistant at the University of Toronto.
According to IAC Acoustics, a quiet suburb, conversation at home and large electrical transformers at 100 feet all come in at 50 decibels. A library and a bird call, meanwhile, come in at 40 decibels and a whisper and rustling leave register at about 20 decibels.
Barry added that respondents who live closer to the turbines “were more likely to report being annoyed than respondents who live further away.”
The Statistics Canada study found no direct connection 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 measured via hair cortisol or self-reported).
However, the new study shows respondents closer to wind turbines reported lower ratings for their environmental quality of life. The team notes their report cannot determine 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,” said co-author Sandra Sulsky, a researcher from the engineering company Ramboll, which funded the new report. “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 new study also did not identify direct evidence that wind turbine exposure actually impacts human health, but, going forward, “measuring the population’s perceptions and concerns before and after turbine installation may help to clarify what effects – if any – exposure to wind turbines may have on quality of life,” Sulsky said.