Abstract
Introduction
This study used ambulatory sleep studies to examine potential relationships between wind farm sound pressure level ([SPL] in dBA) and amplitude modulation (AM) on conventional measures of sleep quality in individuals residing within 10 km of a wind turbine in Australia.
Methods
Twenty six individuals (42:58%, females:males) aged (mean ± standard deviation) 53.2±12.2 years and residing 2.9±1.7 km from the nearest wind turbine underwent two consecutive ambulatory sleep studies and detailed indoor time-synchronised acoustic recordings inside their home. Associations between averaged whole night SPL and AM prevalence versus sleep onset latency, wake after sleep onset (WASO), percentage of sleep in each stage, sleep efficiency and total sleep time on each recording night were explored using bivariate and multiple regression analyses, using log-normalised data where required.
Results
Forty-five technically successful sleep studies (24 night 1, 21 night 2) were available for analysis. On night 2, AM prevalence explained 18.9% of the variance in sleep efficiency (R=.434, F(1,19)=4.421, p=0.049) and SPL explained 23.5% of the variance in WASO (R=.484, F(1,19)=5.821, p=0.026) in multiple regression analyses adjusting for age. No other sleep macrostructure variables were associated with AM prevalence or SPL on either night.
Conclusion
Weak relationships between SPL and AM prevalence and sleep outcomes in a real-world wind farm noise exposure setting support the need for more detailed investigations of potential wind farm noise effects on sleep quality.