Biology Reference
In-Depth Information
Noise pollution is a growing worldwide phenomenon affecting millions of
people. In Europe alone 80 million people are exposed to an unacceptable dose of
noise. In an undeveloped country, noise exposure has a major impact.
Direct and indirect effects of noise exposure on human health produces hearing
impairment, reduction of speech communication, cardiovascular risk, sleep distur-
bance, psychological and performance reduction effects, and a subjective feeling of
annoyance. Exposition to outdoor noise represents the highest risk to human health
where insomnia is one of the most common effects, but in the long term ischemic
heart disease and rising blood pressure have to be considered equally probable.
The soundscape of urban spaces is a complex system in which physical, psycho-
logical, and social components concur to human sonic assessment. A sonic envi-
ronment of high quality in urban areas means not only a low level of sonic energy
but also the presence of natural elements such as green spaces and a tangible
biodiversity.
Urban parks are areas where people find physical and psychological advantages,
thanks to several positive cognitive objects such as peacefulness and quietness and
natural physical natural objects such as trees, flowers, and animals. In urban parks
visitors have been demonstrated able to extract positive acoustic cues such as
natural sounds and happy people sounds.
Pleasant sounds reduce the relationship between sound pressure level and the
acoustic comfort. The age of subjects is important: teenagers are more unsatisfied
with acoustic comfort when compared with older groups.
Sonic and visual objects are major actors in the urban landscape, but the sound
has distinctive characters compared to the visual objects. In fact, sound has no
precise border and is ubiquitous; the aural harmonization is temporal and is a field
of energy. A sound could be less rich in information but full of emotion. Rating a
soundscape largely depends on the individual skill, experience, attentiveness,
cultural model, and social and economic stratum.
Passive soundmarks are defined as every sonic object that is perceived as a
priority by a listener such as fountains and sonic sculptures, whereas active
soundmarks are the result of interesting activities (concerts, talks, local markets).
The combination of visual and acoustic cues creates an informative space that
can be useful to manage and to reduce anthropogenic noise, and definitively to
improve the quality of the soundscape. Some natural sounds such as water contrib-
ute to improve the appreciation of natural and manmade spaces, and the combina-
tion of visual and acoustic stimuli represents efficient strategies to assess the value
of a landscape and the associated soundscape. Soundscape evaluation is generally
performed by administrating questionnaires that have specific sections, such as
(1) perception of urban soundscape; (2) soundmark; (3) semantic differential, and
(4) individual information.
The possibility to benefit from quiet areas reduces in people the annoyance effect
with physiological benefits, but to achieve this result the level of noise must be at
least below the 60 dB
L
Aeq, 24 h
.
The assessment of the human-perceived soundscape requires diverse fields of
practices and competencies such as sound quality, human acoustic comfort in
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