van den Berg[17] showed that sound is the most annoying
aspect of wind turbines, and is more of a problem at night.
A large proportion (23/39) of respondents from the turbine
group identified turbine noise as a problem and rated it to be
extremely annoying. It should be noted that, in contemporary
medicine, annoyance exists as a precise technical term
describing a mental state characterized by distress and
aversion, which if maintained, can lead to a deterioration
of health and well-being.[25] A Swedish study[26] reported
that, for respondents who were annoyed by wind turbine
noise, feelings of resignation, violation, strain, and fatigue
were statistically greater than for respondents not annoyed
by turbine noise. An attempt at constructing dose-response
relationships between turbine noise level and annoyance in
a European sample suggests that at calculated noise levels of
30-35 dB(A), 10% of the sample was rather or very annoyed
at wind turbine sound, increasing to 20% at 35-40 dB(A) and
25% at 40-43 dB(A).[15]