Sources of Noise
Dr. Riaz Shaikh
2 Sources of Noise Pollution.
The word noise is derived from the Latin term nausea. It has been defined as
unwanted sound, a potential hazard to health and communication dumped into
the environment with regard to the adverse effect it may have on unwilling ears.
Noise can also be defined as unwanted sound. Sound, which pleases the
listeners, is music and the sound which causes pain and annoyance is noise. At
times, what is music for some can be noise for others.
The Air (Prevention and Control of Pollution) Act (1981):
The Air (Prevention and Control of Pollution) Act, 1981 includes noise in the
definition of ‘air pollutant’.
According to this act “Air Pollutant” can be defined as!
Air pollution means any solid, liquid or gaseous substance including noise
present in the atmosphere such concentration as may be or tent to injurious to
human beings or other living creatures or plants or property or environment.
century the definition of noise modify somewhat like this!
“Noise- a sound; a harsh disagreeable sound, or such sound; a din. Pollution- an
excessive or annoying degree of noise in a particular area, e.g. from traffic or
aero plane engines.”
Noise can be described as sound without agreeable musical quality or as an
unwanted or undesired sound. So noise can
be taken as a group of laud, non-
harmonious sounds or vibrations that are
unpleasant and irritating to ear.
Units of Noise or Sound:
A Decibel is the standard for the
measurement of noise. The zero on a
decibel scale is at the threshold of hearing,
the lowest sound pressure that can be
heard, on the scale.
3 Sources of Noise Pollution.
Maximum Level of Noise (dB) Area
20 dB Whisper
40 dB Quiet office
60 dB Normal conversation
80 dB Physically painful sound
Sources of Noise Pollution:
Mainly “Noise Pollution” is classified into two major categories:
1) Natural Sources
2) Anthropogenic Sources
Anthropogenic sources are further classified into two major categories that is:
1) Mobile Sources
2) Stationary Sources
Classification of Noise:
a) Natural Sources:
Noise pollution can affect the surrounding environment by causing
negative reactions in people and animals in that environment. While nature is
not in itself considered to be a creator of noise pollution, any excessive noise
from elements of nature can be overwhelming to nearby inhabitants, and
therefore be considered as such.
Insects can be very noisy and therefore a natural form of noise pollution,
e.g.; rickets chirping on summer nights to the
enormous swarms of Cicada that live around
the world, bugs can create a lot of noise.
Birds are naturally noisy creatures,
singing and chirping everywhere all the time,
except during times of the year when they
migrate to cooler or warmer climates.
The pets and animals that live on
nearby farms can moo, bark, squeal,
4 Sources of Noise Pollution.
squawk, quack and wail. These noises combined can certainly create
4) Thundering and Lightening:
Thundering and lightening of clouds create intense noise which
frightened the people around.
5) Storms and High Winds:
High winds and storms can block out all other noise and cause fear in
those experiencing the storm, even if there is no threat.
6) Sound of waves:
Sound of waves on sea shore produce an intense noise on the shoreline
b) Anthropogenic Sources:
There is a great amount of anthropogenic sources of noise pollution such
i. Road Traffic Noise:
The main sources of traffic noise are the
motors and exhaust system of autos,
smaller trucks, buses, and motorcycles.
ii. Air Craft Noise:
Low flying military aircraft produces
intense noise pollution and gained public
attention during the recent years.
iii. Noise from railroads:
Rail car retarders can produce a high
frequency, high level screech that can
reach peak levels of 120 dB at a distance
of 100 feet, which translates to levels as
high as 138, or 140 dB at the railroad
iv. Construction Noise:
Different kind of equipment’s used in
the construction produces intense noise
5 Sources of Noise Pollution.
v. Noise in Industry:
Industrial noise is one of the less prevalent community noise problems.
Neighbors of noisy manufacturing plants can be disturbed by sources
such as fans, motors, and compressors etc.
vi. Military exercises and Defense programmes:
Launching of rockets, explosions, shooting ranges and military exercises
are also causes intense noise
vii. Mining operations:
Mining operations also create loud
noise in the surrounding areas of
viii. Public addressing tools:
Public addressing Tools also create
intense noise pollution such as uses of
loud speakers etc.
ix. Public Noise:
Noise produces in the public areas is too much intense such as in the
parks, underground railway stations etc.
Mobile and Stationary sources of noise pollution:
Anthropogenic sources are further classified into two major categories
I. Mobile sources
II. Stationary sources
Mobile and stationary sources are shown in the following table
Mobile sources Stationary sources
Transportation Industrial noise
Rail roads Boilers noise
Air crafts Construction activities
Storms and Winds Generators
Vehicles Gas stations