When talking about pollution in
general people usually refer to air and water pollution neglecting the global
threat of noise pollution. They seem to forget or are not aware of the fact that
noise pollution is disturbing life of all biota present in ecosystem.
***Generically, the term 'noise' is used to refer to any unwanted sound. This
may range from the sound created when you hammer a nail into a wall, to the
sound created by an aircraft overflying your house. Noise pollution describes
any sound created by people, animals, and machines that disturbs the
environment.
Urbanization, economic growth and motorized transport are some of the driving
forces for environmental noise exposure and health effects. Environmental noise
is defined as noise emitted from all sources except industrial workplaces.
The response of the human ear to sound depends both on the sound frequency
(measure in Hertz, Hz) and sound pressure, measure in decibels (dB). The WHO
guidelines for community noise recommend less than 30 A-weighted decibels (dB(A))
in bedrooms during the night for a sleep of good quality and less than 35 dB(A)
in classrooms to allow good teaching and learning conditions.
***The WHO guidelines for night noise recommend less than 40 dB (A) of annual
average (L night) outside of bedrooms to prevent adverse health effects from
night noise.
dB Decibel − units used to measure sound pressure levels on a logarithmic scale.
dB(A) A-weighted decibel − a measure of sound levels as experienced by humans,
calculated using a spectral sensitivity factor (A-filter) that weights sound
pressure levels by frequency to correspond to the sensitivity of the human ear.
Decibel Levels of Environmental Sounds
Source--Dangerous Level dBA SPL***
Produces Pain 120-140
Jet Aircraft During Takeoff (at 20 meters) 130
Snowmobile
Tractor Without Cab 120
Rock Concert 110
Die Forging Hammer
Gas Weed-Whacker
Chain Saw
Pneumatic Drill 100-105
Home Lawn Mowers 95 to 100 dB
Semi-trailers (at 20 meters) 90
Source-- dBA SPL***
Discomfort Level Above 80
Heavy Traffic 80
Automobile (at 20 meters) 70
Vacuum Cleaner 65
Conversational Speech (at 1 meter) 60
Quiet Business Office 50
Residential Area at Night 40
Whisper, Rustle of Leaves 20
Rustle of Leaves 10
Threshold of Audibility 0
*** Franks JR, Stephenson MR, Merry CJ. Preventing occupational hearing loss. A
practical guide. DHSS (HIOSH) pub. No. 96-110. And National Institute of
Deafness and Other Communicative Disorders: Noise Induced Hearing Loss.
Noise Pollution Health Hazards;
Noise has become a very important "stress factor" in the environment of man. The
term "noise pollution" has been recently used to signify the hazard of sounds
which are consequence of modern day development, leading to health hazards of
different type.
Continuous exposure to high decibel noise can result in some adverse effects on
your health. One of these hazards is acoustic trauma to the ears caused when
they are subjected to the sound of an intensity of 85 dB or more without
respite.
The health hazards of noise pollution can be categorized into physiological and
psychological hazards. While the former includes hearing loss, hypertension,
disturbance in sleep patterns etc., the later includes problems such as
annoyance, aggression and stress.
Noise induced hearing loss is one of the most harmful effects of noise
pollution. More importantly, these harmful effects of noise pollution are not
just restricted to human beings, even animals has to bear the brunt of the same.
Studies reveal that the increase in the noise levels beyond a certain extent
tends to interfere with the communication of the animals, thus resulting in
disturbance in their various life processes which is also true for us.
It is generally accepted that the link between excess noise and hearing loss is
obvious. But this fact is supported by epidemiological studies that compared the
prevalence of hearing loss in different categories of occupations, or in
particularly noisy occupations. Although other factors may also contribute to
hearing loss, such as exposure to vibrations, ototoxic drugs and some chemicals,
the association with noise remains robust after accounting for these influences.
Noise Pollution Effect on Public Health
• Globally, more than 20 million people are estimated to have hearing
difficulties.
• More than half dozen people in EU countries are living in noisy soundings; a
third expensive level that disturbs sleep.
• In EU countries about 40% of the population is exposed to road traffic noise
at levels exceeding 55 db (A); 20% is exposed to levels exceeding 65 dB (A)
during the daytime; and more than 30% is exposed to levels exceeding 55 dB (A)
at night.
• Approximately 30 million Americans are exposed to high intensity noise above
85 db in their workplace in one in 4 of these workers (or 7.5 million Americans)
a permanent hearing loss will develop, compared more than nine million people in
1981.
• In Germany and other developed countries as many as 4- 5 million that is 12-
15 % of the employed people are exposed to noise level of 85db or more.
Although most developed nations have government agencies responsible for the
protection of the environment, no nation has a single body that regulates noise
pollution. Transportation noise is usually regulated by the relevant
transportation ministry, health-related work noise is often regulated by health
ministries and worker’s unions, and entertainment noise such as loud music is a
criminal offense in many areas. Little is currently being done to reduce noise
pollution in developed countries.
Impact of noise on aquatic animals;
Some scientists believe that noise pollution could have a negative impact on the
entire marine food web chain. One of the latest studies by the Technical
University of Catalonia in Barcelona showed that dolphins and whales are not
only marine animals seriously affected with noise pollution as squids and
octopuses are also experiencing massive acoustic trauma because of the increased
noise pollution in our oceans.
Impact of noise on birds;
Some people just want some peace and quiet, and apparently, so do the birds. The
University of Colorado at Boulder has conducted a three-year study that proves
in July 2009 that noise pollution affects birds and their habits. The biggest
problem that birds face when there is too much noise is their ability to
communicate. Birds that vocalize at lower frequencies are easily drowned out by
noise pollution, affecting their ability to attract a mate and socialize with
the other birds in their community. But finches and other birds that vocalize at
a higher frequency appear uninfluenced by the hustle and bustle of noise
pollution--apparently ignoring the mass exodus of their fellow, winged friends.
“When bombarded by noise pollution, some male birds begin to sing higher tunes
and that tonal shift makes them less attractive to females”. Said Wouter
Halfwerk, a behavioural ecologist at Leiden University in the Netherlands. "It
could very well be that noise pollution is interfering with reproductive
decisions by females." Previous studies have shown that a variety of birds can
suffer when they change their songs, said Erin Bayne, an ornithologist at the
University of Alberta. The new study is one of the first to explain why.
Most recent in human beings the major negative impact is insomnia which is root
cause of many diseases, although more research is in progress.