Estimating community tolerance for wind turbine noise annoyance

Abstract

A-weighted WTN contributed less than 10% to the strength of the multiple regression model developed for wind turbine noise (WTN) annoyance in Health Canada’s Community Noise and Health Study (CNHS). Improvements required consideration of non-LAeq variables unknown or even inapplicable beyond the CNHS. To facilitate cross-study comparisons, an analysis of WTN annoyance was conducted based on the community tolerance level (CTL) model. The rate of increase in WTN annoyance was effectively estimated using a loudness function, as shown in Eq. (1). %HA = 100 exp (-(1/[10((DNL-CTL + 5.306)/10)]0.3)). (1) By convention, CTL is the DNL from Eq. (1) where 50% of the community would be highly annoyed. The CTL for WTN annoyance from field studies published to date ranges from 57.1 to 64.6 DNL (mean = 62, σ = 3). CTL values developed by others for transportation noise sources suggest that, on average, communities are between 11 dB and 26 dB less tolerant of WTN than of other sources, depending on the source. Confidence in these results should increase as future studies in this area produce additional estimates for the relationship between WTN level and the prevalence of high annoyance. The CTL analytical methods, assumptions, strengths, and limitations are presented.