Health Canada plans its own primary research to paint “a more complete picture” of the potential health impacts on rural Canadians from life near wind turbine farms.
The federal department on Tuesday announced it will work with Statistics Canada on a new peer-reviewed study, for completion sometime in 2014, on “the relationship between wind turbine noise and the extent of health effects reported by, and objectively measured in, those living near wind power developments.”
Today there remains “insufficient evidence” to conclude whether a relationship exists between exposure to noise from wind turbines and adverse human health effects, the department said, noting “community annoyance and other concerns have been reported to Health Canada and in the scientific literature.”
That said, the most rigorous studies available worldwide to date “do not show a link between exposure to wind turbine noise and harm to human health,” Health Canada said.
As of May this year, Canada’s installed capacity for wind turbine-generated power was 5.4 gigawatts, up nearly sevenfold from 2005. The wind energy industry plans by 2025 to supply 20 per cent of Canada’s electricity demands, up from 2.3 per cent currently.
The department’s ability to provide advice to residents on noise impacts from wind turbines has so far been “challenged” by limited peer-reviewed scientific research on the character of wind turbine noise — and by a lack of Canadian prevalence data on community complaints and self-reported health impacts from studies with “rigorous methodological designs.”
Wind turbine noise is known to include the production of low frequency sound which, beyond the auditory threshold, is “more annoying than that at higher frequencies,” Health Canada said.
Low-frequency sound also travels further than higher frequency sound, can penetrate structures such as homes without much reduction in energy, and can create indoor noise problems such as perceptible vibration and rattle.
As a result, there has been “considerable attention generated internationally and nationally by advocacy groups, concerned citizens and media” on the potential heath impacts from exposure to wind farm noise, Health Canada said.
Such attention has included concern that the presence of wind turbines near residential dwellings may not only negatively impact property values, but also pose a public health risk to nearby residents.
Other farmers and rural residents have stood to gain, however, through land lease payments from wind farm operators or developers for current or future use of their property.
Wind turbines are often set up in rural communities where background sound levels are typically low, so the turbine noise may be “particularly problematic” for rural residents, Health Canada said.
Such noise “may be more noticeable” and neighbouring residents may experience “large changes in sound levels, with unpredictable operating times and variable wind conditions.”
While provincial and territorial governments won’t be involved in this study, its results will be shared with them, Health Canada said.
Provincial and municipal governments regulate noise and the location of wind power projects directly through legislation, guidelines and/or bylaws, applying either broadly or only to specific project types or sectors, the department noted.
Health Canada’s approach in this study is expected to “support decision makers by strengthening the evidence base of peer-reviewed scientific research that ultimately supports decisions, advice and policies regarding wind power development proposals, installations and operations in Canada.”
The agencies’ draft methodology has now been posted on Health Canada’s website for a public comment period ending Aug. 8.
That draft won’t include specific details related to the study locations, timing and survey components until the research project is done, so as to protect the “integrity of the study” as “premature disclosure may lead to bias in the research setting,” Health Canada said.
All findings, including those additional details of the study methodology, are to be released and published in 2014 on the Health Canada website and in “peer-reviewed scientific literature” once the study’s completed.
Generally, however, Health Canada said its study will focus on an initially targeted sample size of 2,000 dwellings, at setback distances ranging from less than 500 metres to greater than five kilometres from between eight and 12 wind turbine installation facilities across the country.
Health Canada and Statistics Canada will run a “cross-sectional field study” evaluating residents’ self-reported health impacts and symptoms of illness against “objective biomarkers” of stress and the sound levels from wind turbines, including low frequency noise.
“This data will be correlated with calculated wind turbine noise so that any potential relationship to reported health symptoms can be reliably determined,” Health Canada said.
The research design calls for a 25-minute computer-assisted personal interview, using a questionnaire made up of modules that probe endpoints such as “noise annoyance, quality of life, sleep quality, stress, chronic illnesses and perceived impacts on health.”
Once the interview is done, the subject will be invited to take part in the health measures collection part of the study, which is to include an automated blood pressure measurement and the collection of a small hair sample, meant to provide a 90-day retroactive average cortisol level.
The subject’s sleep patterns will be evaluated using actigraphy for a period of seven consecutive days, synchronized with wind turbines’ operation data.
Environmental sound level measurements, including low frequency noise, will be taken both inside and outside a sub-sample of homes in order to validate parameters ensuring accurate sound level modeling, Health Canada said.
The data from the completed study is expected to “contribute to the global knowledge of the relationship between wind turbine noise and health” and to provide “additional insight into an emerging issue,” Health Canada said.
“However, the results will not provide a definitive answer on their own.”
The study results could, however, be compared to the prevalence of other community health concerns — and to the prevalence of “similar” health concerns in communities that aren’t near wind farms, Health Canada said.
Ont. farmers urge halt to wind turbine development, Jan. 20, 2012
No direct link between wind farms, illness: report, May 24, 2010