Human Dimension of the Soundscape: From Individuals to Society - Soundscape Ecology: Principles, Patterns, Methods and Applications - page 108

In natural areas far from a significant source of noise pollution where the
A-weighted sound pressure level is 20 dB it is possible to hear a snowmobile at

3-5 km and an aircraft at 15-20 km. In this case, the assessment of the sonic
environment is modified significantly in respect to a sonic environment in which the
background noise is higher and able to mask key sounds.
The sonic quality of an environment has absolute values in terms of sound
pressure level but subjective interpretation and effects according to the area, the
people, and the circumstance in which people are engaged. Annoyance and quality
of the sonic environment are strictly connected, and annoyance (see Sect. 5.4 )
becomes a relative parameter of noise exposure.
Sophisticated acoustical and psycho-acoustical measurable and quantifiable
parameters are today available. Soundscape characters can be described by words
or measured with numbers, but the best result is obtained when both methods are
combined. A soundscape is not only words or numbers but rather their meaningful
combination.

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5.3 Noise Sensitivity

People have different reactions to different noise levels for many reasons, princi-
pally connected to personal experience, culture, and context. In 1978 Weinstein
proposed a noise sensitive index (Weinstein 1978 ) (Table 5.1 ), an approach able to
determine a score between people and noise annoyance. In fact, there is interindi-
vidual sensitivity of people at different noise levels.
Noise sensitivity is defined as an attitude to rating sound according to an
individual-based criterion and represents a major antecedent of individual noise
annoyance. Job ( 1999 ) defines noise sensitivity (NS) as “ Noise sensitivity refers to
the internal states (be they physiological, psychological [including attitudinal], or
related to life style or activities conducted) of any individual which increase their
degree of reactivity to noise in general. ”
Noise sensitivity has indirect effects on health, creating a stressful psychological
condition, increasing psychological reactivity of the cardiovascular system and
covarying with the degree of psychopathology. Noise-sensitive people (NSP)
have significantly greater increases in heart rate and systolic and diastolic blood
pressure when compared with non-sensitive noise people (NNSP). Non-sensitive
noise people seem more connected to psychiatric problems such as phobic disorders
and depression. Neurotic people seem more sensitive to noise level when by the
term neurotic we mean a person who is too nervous or unstable.
This difference depends not only on a different hearing capacity but by other
causes. For instance, when exposed to 80 dB of an helicopter there are no significant
differences between noise-sensitive people and non-noise sensitive people.
Noise sensitivity represents a personal trait that is stable over time.
Noise exposure (NE) is the first factor of noise annoyance but after this the major
factor is represented by individual noise sensitivity (INS). According to Job ( 1988 ),