No direct link between wind turbines and adverse health impacts

The review was conducted by Drs. Loren D. Knopper and Christopher A. Ollson of the Canadian consulting firm Intrinsik Environmental Services, Inc., and their findings appeared in an article published in the Journal of Environmental Health (Knopper and Ollson: "Health effects of wind turbines: A review of the literature," Environmental Health 2011, 10:78). Intrinsik frequently performs analyses of wind turbine sound for wind farm developers.

In the abstract to their article, the authors comment that "People interested in [the debate about health effects of turbine sound] turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet."

Not surprisingly, they find that the methods and conclusions of these sources differ: "Conclusions of the peer-reviewed literature differ in some ways from those in the popular literature. In peer-reviewed studies, wind turbine annoyance has been statistically associated with wind turbine noise, but found to be more strongly related to visual impact, attitude to wind turbines and sensitivity to noise. To date, no peer-reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects. If anything, reported health effects are likely attributed to a number of environmental stressors that result in an annoyed/stressed state in a segment of the population. In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured." (emphasis added)

Although both peer-reviewed and popular sources agree that wind turbines are annoying to some people, Knopper and Ollson write, given the fact that annoyance is more strongly correlated with other causes such as visual impact, "[I]t appears that it is the change in the environment that is associated with reported health effects and not a turbine-specific variable like audible noise or infrasound."

Tom Gray, www.awea.org/blog/