Zusammenfassung
The document critically reviews the adverse effects of community noise,
including interference with communication, noise-induced hearing
loss, annoyance responses, and effects on sleep, the cardiovascular
and psychophysiological systems, performance, productivity, and social
behavior. Noise measures or indices based only on energy summation
are not enough for the characterization of most noise environments.
This is particularly true when concerned with health assessment and
predictions. It is equally important to measure and display the maximum
values of the noise fluctuations, preferably combined with a measure
of the number of noise events, and to assess whether the noise includes
a large proportion of low frequency components. For dwellings, recommended
guideline values inside bedrooms are 30 dB LAeq for steady-state
continuous noise and for a noise event 45 dB LAmax. To protect the
majority of people from being seriously annoyed during the daytime,
the sound pressure level from steady, continuous noise on balconies,
terraces, and in outdoor living areas should not exceed 55 dB LAeq.
To protect the majority of people from being moderately annoyed during
the daytime, the sound pressure level should not exceed 50 dB LAeq.
At nighttime outdoors, sound pressure levels should not exceed 45
dB LAeq, so that people may sleep with bedroom windows open. In schools
and preschools, to be able to hear and understand spoken messages
in class rooms, the sound pressure level should not exceed 35 dB
LAeq during teaching sessions. For hearing impaired children, a still
lower level may be needed. The reverberation time in the class room
should be about 0.6 s, and preferably lower for hearing impaired
children. For assembly halls and cafeterias in school buildings,
the reverberation time should be less than 1 s. For outdoor playgrounds
the sound pressure level from external sources should not exceed
55 dB LAeq. In hospitals during nighttime, the recommended guideline
values for wardrooms should be 30dB LAeq together with 40 dB LAmax.
Since patients have less ability to cope with stress, the equivalent
soundpressure level should not exceed 35 dB LAeq in most rooms in
which patients are being treated, observed or resting. The concern
for protecting young people’ s hearing during leisure time activities
warrants provisional guidelines for concert halls, outdoor concerts
and discotheques. It is recommended that patrons should not be exposed
to sound pressure levels greater than 100 dB LAeq during a 4-hour
period. The same guideline values apply for sounds played back in
headphones when converted to equivalent free-field level. To avoid
hearing deficits from toys and fireworks, performers and audience
should not be exposed to more than 140 dB(peak) of impulsive sounds.
Existing large, quiet outdoor areas in parkland and conservation
areas should be preserved and the background-to-noise ratio be kept
low
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