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Introduction
Noise can be defined as unwanted or undesirable sound. The word noise is derived from a Latin word nausea meaning seasickness.

Be it human or machine-created noise disrupts the activity and balance of life. Humans, animals, plants and even inert objects like buildings, monuments and bridges have been the victims of noise pollution.

Noise pollution is considered as major hazards of modern life especially in urban areas-areas that are most industrialized and urbanized.

Materials related to Sound
Sound Waves
Sound waves are caused due to variation in pressure above or below the static value of atmospheric pressure.

Frequency of sound
Frequency is the rapidity with which pressure variation occurs. It is measured in hertz. Audible frequency is a periodic vibration whose frequency is audible to average human.
Weighting networks
¢ The simplest method of measuring noise pollution is by assessing linear sound pressure level over a broad frequency level band covering the whole of audible frequency band.
¢ Filtering networks are used to measure the sensation whose sensitivity varies as that of human ear.
¢ Widely used weighting network is ˜A™ weighing. They are represented as dB A.




Decibel
Decibel is widely used as measure of sound level. The ratio of the lowest sound power level to loudest power level is approximately one to one million.
Sound Power level, Lw= 10 log10 (W/ Wref)
Sound Pressure level , Lp= 20 log10 (P/ Pref)

Parameters that affect measurement


Sound Pressure Level vs. Distance from the Source
Attenuation of Sound
Wind Effects
Air Absorption
Temperature Gradient
Ground Attenuation






Sources causing Noise Pollution
Road Traffic Noise


Aircraft Noise


Noise from Railroads






Effects
Interference with communication

Noise induced hearing loss

Effects on sleep







Effects on performance behavior

Other health effects



Sound level meter
Noise Pollution and Control Rules 2000
Ambient noise limits
conclusion
Control measures
Immediate measures
Proper maintenance of vehicles
Thick vegetation and growing trees on road side
By lodging a formal complaint
Raising obstruction and barriers between noise sources and residences.



References


ËœNoise and its Effectsâ„¢, Dr. Alice H. Sutter ( 19-28,36-42,98-103)
Environmental Pollution
Anmol Publication
B.D. Sharma ( 34,35,86-91)
Status of Noise in Industrial area, Bangalore
Paper Presented and published at 94th session of ISC
(Dr. B. Shanthaveerana Goud ,Dr. Jayamma, Dr.Nandini, Prof. Devraj)







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