Noise pollution is caused by
unwanted sounds that intrude into our daily lives. The increasing density in
urban planning has made it essential to deal with this problem.
Noise is a pollutant that is
controllable and is amenable to abatement technology. Standards have been set
out by the Environmental Protection Agency which sets the standards for
allowable noise levels for the human ear. Noise intensity is measured in
decibels and the scale by which it is measured is logarithmic. This means that
a 10 decibel increase in noise constitutes a doubling of loudness.
Distance also reduces the
noise reaching the ear the further a person is away from the source of noise.
Noises above 45 decibels will disturb a person’s sleep, while noises above 120
decibels can become painful and cause hearing damage. Besides hearing damage,
noise can also affect persons in other ways that would need them to seek
medical attention. Sound level meters measure the pressure levels caused by the
sound and translate them into electrical impulses that are registered on a
meter. Digital sound level meters can measure noises in the range of 40 to 130
decibels with an accuracy of ~+mn~2 decibels.
Noise pollution is caused by
people or machines that produce a high environmental noise that has a
deleterious effect on the health of humans and animals. Vehicles and engines
like generators, compressors, and drilling machines are the chief causes of
noise pollution in urban areas. The noise levels are further accentuated by the
reflecting surfaces of buildings and glass which can amplify these noises till
they reach unbearable levels.
The rhythmic nature of the
noise created by these urban machines, or by audio systems used for
entertainment, causes constant irritation to the ear. City planners have set
standards for allowable noise and also have laws in place which allow such
equipment only at particular times. Noise abatement methods using sound baffles
or absorbers are nowadays standard fitments in buildings and on urban roads.
Manufacturers of transportation and other equipment have also addressed the
matter of urban noise pollution by introducing sound absorbing techniques
around their engines.
Noise is one of the leading
causes of hearing impairment that afflicts a substantial portion of the human
population especially around urban centers. Such
impairment is permanent and is now even occurring at very young ages due to the
proliferation of audio systems and their constant use by the younger generation.
Health effects are noticed
once noise levels cross 85 decibels and exposure to the noise is for a
prolonged length of time. Loudness of noise doubles with every 10 decibel
increase in noise levels and damage to hearing can be caused by even very short
exposure to it. The damage to hearing is caused by the noise affecting the hair
cells in the inner ear which are very delicate and can get irretrievably
damaged.
Damage to hearing can be
reduced with the use of ear plugs or ear muffs and their use is now recommended
for most industrial workers exposed to constant noise. Turning down the volume
of audio equipment and reducing the time spent in noisy environments can also
help to reduce hearing damage.
Auditory effects of noise on
animals are the same as in humans and can involve hearing loss and a reduced
sensitivity to noise. This affects the animals functioning abilities and can
cause their hunting faculties to be reduced.
Noise causes stress. This in
turn can produce hormonal changes in animals that affect their fight or flight
responses. They will have reactions that are not appropriate, and this can
affect their energy resources which in turn can make them more susceptible to
predators or disease.
Noise can also disrupt behavioral patterns in animals and may force them to
change their habitats which will then directly impinge on their survival in
conditions that they are unused to.
Noise can affect those animals
the most which are dependent on their auditory senses for their survival. It
could also affect their abilities to communicate and thus their mating
activities.