Abstract
Aims The aims of this thesis were to describe and gain an understanding
of how people who live in the vicinity of wind turbines are affected
by wind turbine noise, and how individual, situational and visual
factors, as well as sound properties, moderate the response. Methods
A cross-sectional study was carried out in a flat, mainly rural area
in Sweden, with the objective to estimate the prevalence of noise
annoyance and to examine the dose-response relationship between A-weighted
sound pressu... mer
re levels (SPLs) and perception of and annoyance with wind turbine
noise. Subjective responses were obtained through a questionnaire
(n = 513; response rate: 68%) and outdoor, A-weighted SPLs were calculated
for each respondent. To gain a deeper understanding of the observed
noise annoyance, 15 people living in an area were interviewed using
open-ended questions. The interviews were analysed using the comparative
method of Grounded Theory (GT). An additional cross-sectional study,
mainly exploring the influence of individual and situational factors,
was carried out in seven areas in Sweden that differed with regard
to terrain (flat or complex) and degree of urbanization (n = 765;
response rate: 58%). To further explore the impact of visual factors,
data from the two cross-sectional studies were tested with structural
equation modelling. A proposed model of the influence of visual attitude
on noise annoyance, also comprising the influence of noise level
and general attitude, was tested among respondents who could see
wind turbines versus respondents who could not see wind turbines
from their dwelling, and respondents living in flat versus complex
terrain. Results Dose-response relationships were found both for
perception of noise and for noise annoyance in relation to A-weighted
SPLs. The risk of annoyance was enhanced among respondents who could
see at least one turbine from their dwelling and among those living
in a rural in comparison with a suburban area. Noise from wind turbines
was appraised as an intrusion of privacy among people who expected
quiet and peace in their living environment. Negative experiences
that led to feelings of inferiority added to the distress. Sound
characteristics describing the amplitude modulated aerodynamic sound
were appraised as the most annoying (swishing, whistling and pulsating/throbbing).
Wind turbines were judged as environmentally friendly, efficient
and necessary, but also as ugly and unnatural. Being negative towards
the visual impact of the wind turbines on the landscape scenery,
rather than towards wind turbines as such, was strongly associated
with annoyance. Self-reported health impairment was not correlated
to SPL, while decreased well-being was associated with noise annoyance.
Indications of possible hindrance to psycho-physiological restoration
were observed. Conclusions Wind turbine noise is easily perceived
and is annoying even at low A-weighted SPLs. This could be due to
perceived incongruence between the characteristics of wind turbine
noise and the background sound. Wind turbines are furthermore prominent
objects whose rotational movement attracts the eye. Multimodal sensory
effects or negative aesthetic response could enhance the risk of
noise annoyance. Adverse reactions could possibly lead to stress-related
symptoms due to prolonged physiological arousal and hindrance to
psychophysiological restoration. The observed differences in prevalence
of noise annoyance between living environments make it necessary
to assess separate dose-response relationships for different types
of landscapes.
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