What is low-frequency sound? What about “infrasound”?

Most low-frequency sound and “infrasound” produced by turbines is significantly below the human hearing threshold. Wind turbine infrasound levels are far lower than those experienced in everyday activities such as traveling in a vehicle, being by the ocean, or being out in the wind.

Scientific evidence confirms this sound is not dangerous, and that any low-frequency waves produced are not harmful to those nearby. As reported in a recent study by the Massachusetts Department of Public Health:

 “…the weight of the evidence suggests no association between noise from wind turbines and measures of psychological distress or mental health problems.”

Source: http://www.mass.gov/eea/docs/dep/energy/wind/turbine-impact-study.pdf