A Review of the Potential Impacts of Wind Farm Noise on Sleep

Adequate sleep is important for good health and well-being, and inadequate sleep leads to impaired attention and performance. Persistent poor sleep is also associated with cognitive and metabolic impairment, cardiovascular problems and diminished psychological well-being. Recent growth in wind farm developments has been associated with community complaints regarding sleep disturbance, annoyance and a range of health issues that some attribute to wind farms. Wind turbines create aerodynamic and mechanical noise that, if sufficiently loud, has the potential to disturb residents’ sleep, particularly for those living in close proximity. According to the World Health Organisation (WHO), noise effects on sleep are expected to occur with outside noise levels > 40 dB (A). On the other hand, the WHO guidelines also state that “when prominent low-frequency components are present, measures based on A-weighting are inappropriate”, so uncertainty remains regarding which alternative noise measures and noise limits are most appropriate to mitigate community impacts of wind farm noise on sleep. In Australia, dwellings are typically located > 1 km from the nearest wind turbine where wind farm noise becomes more biased towards lower frequencies (≤ 200 Hz) at low sound pressure levels (< ∼ 40 dB (A) outside) that may or may not be audible inside a dwelling. Nevertheless, as with any environmental noise, wind farm noise has the potential to disturb sleep, via frequent physiological activation responses and arousals affecting the micro-structure of sleep, and the overall macro-structure of sleep, including total sleep time potentially reduced by difficulty falling asleep and returning to sleep following awakenings for whatever reason. Over time, chronic insomnia could potentially develop in individuals with greater sensory acuity and/or those prone to annoyance from environmental noise. However, it is unclear if and how much sleep is disturbed by the relatively low sound pressure levels relevant to wind turbine noise. Good empirical evidence to investigate these plausible mechanisms is sparse. In this paper, we describe the psychophysiological mechanisms that underlie sleep disturbance in response to noise, review current evidence regarding the effects of wind farm noise on sleep, evaluate the quality of existing evidence and identify evolving research in this area.