Noise PollutionNoise Pollution

DefinitionDefinitionNoise pollution can be defined as “ unwanted, unpleasant sound that causes discomfort for all living beings”Sound becomes unwanted when it interferes with normal activities, or disrupts or diminishes one’s quality of life.

Decibel (dB)Decibel (dB)The unit used to measure the intensity of a soundOn the decibel scale, the smallest audible sound is 0dBNormal conversation sound ranges from 35 to 60dB.

NoiseNoiseDistance affects the intensity of soundIf you are far away, the power is greatly diminished

Any sound above 85 dB can cause hearing loss!The loss is related to the intensity and length of exposure

Common Sounds and Common Sounds and their decibel ratings:their decibel ratings:

Near total silence - 0 dBNormal Conversation - 60 dBA lawnmower - 90 dBA rock concert or a jet engine - 120 dBA gunshot or firecracker - 140 dB

Sources of NoiseSources of Noise

• Industrial Noise• Transport Noise• Neighbourhood noise

Industrial NoiseIndustrial Noise• Caused by different machines of numerous

factories, industries and mills• It causes particularly from mechanical saws and

pneumatic drill.• In Chennai 20% of industrial workers are affected

by Hearing problem• Example:

In steel industry, workers near the heavy industrial blowers are exposed to 112dB for 8 hours

Transport NoiseTransport Noise• Transportation systems are the main source of

noise pollution in urban areas.• It includes Road traffic, Rail traffic, Aircraft

noise.• In metropolitan cities- 90dB

Neighborhood NoiseNeighborhood Noise

• It includes disturbance from household gadgets and community.

• TV,VCR, Radio, Telephones, Loudspeakers etc.,

Health EffectsHealth EffectsNoise pollution adversely affects the lives of millions of people.Studies have shown that there are direct links between noise and health.

Health EffectsHealth Effects• Contraction of Blood Vessels.• Excessive secretion of adrenalin hormone- High BP.• Blaring sounds causes mental distress and heart

attacks, neurological problems, birth defects.• Impairment of hearing.

Noise-Related Noise-Related IllnessesIllnesses

High blood pressureSpeech interferenceSleep DisruptionInsomniaDepressionNoise Induced Hearing Loss (NIHL)

Control MeasuresControl Measures1.Source control

Source modifications such as acoustic treatment to machine surface, design changes, limit the operational timings.Roadway noise can be reduced through the use of noise barriers, speed limits, and traffic control technologyAircraft noise can be reduced by: quieter jet engines, and rescheduling take off and landing times

Control MeasuresControl Measures2.Transmission path intervention

Industrial noise can be reduced by installing noise barriers in the workplaceResidential noise (power tools, loud radios) can be controlled though local laws and enforcement.

Control MeasuresControl Measures• Planting bushes and trees in and around sound generating

sources is an effective solution for noise pollution.

• Regular servicing and tuning of automobiles can effectively reduce the noise pollution.

• Buildings can be designed with suitable noise absorbing material for the walls, windows, and ceilings.

• Workers should be provided with equipments such as ear plugs and earmuffs for hearing protection.

Control measuresControl measures

• Similar to automobiles, lubrication of the machinery and servicing should be done to minimize noise generation.

• Soundproof doors and windows can be installed to block unwanted noise from outside.

• Regulations should be imposed to restrict the usage of play loudspeakers in crowded areas and public places.

• Factories and industries should be located far from the residential areas.