245_Noise_pollution_ppt.ppt

8/13/2019 245_Noise_pollution_ppt.ppt

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Noise po llu t ion


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What is noise pollution?

Noise pollution(or environmental noise) is

displeasing human, animal or machine-created

sound that disrupts the activity or balance of

human or animal life.


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The source of most outdoor noiseworldwide is mainly construction

and transportation systems,including motor vehicle noise, aircraftnoise and rail noise. Poor urbanplanning may give rise to noise pollution,

since side-by-side industrial andresidential buildings can result in noisepollution in the residential area.


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Souces of noise pollution.

Industrial

Commercial

Social

Cultural

Transportation


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Industrial Noise refers to noise that iscreated in the factories which is jarringand unbearable. Sound becomes noiseonly it becomes unwanted and when it

becomes more than that it is referred toas "noise pollution". Heavy industrieslike shipbuilding and iron and steel havelong been associated with NoiseInduced Hearing Loss (NIHL).

.Industrial Noise


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-Industrial and commercial noise pollution.

This is posing to be a big challenge with verypassing day and is a threat to safety and health ofthe people who are working in the industry and

common people as well. It has been scientificallyproved that noise more than 85 decibels cancause hearing impairment and does not meet thestandards set for healthy working environment.

Industrial Noise resulting to noise pollution has

many reasons such as industries being close tohuman habitats which prevents the noise fromdecaying before it reaches human ear.


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Effects of industrial noise pollution

It has already been stated that continuous exposure to noise pollutionleads to hearing impairment but it has various other effects as wellwhich are as follows:

It can result into increase in blood pressure

Increased stress

Fatigue

Stomach ulcers

vertigo

Headaches.

Sleep disturbance

Annoyance

Speech Problems

Dysgraphia, which means writing learning impairment

Aggression

Anxiety

Withdrawal


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Road Transportation Noise

Road accounts for approximately 70% of totalnoise emissions by transportation. It must benoted that different road transportation modes

have different scales of noise emissions. Main sources of noise come from the engineand

the friction of the wheelsover the road surface.Further, travel speed and the intensity of traffic are

directly linked with its intensity of noise. Forinstance, one truck moving at 90 km/hr makes asmuch noise as 28 cars moving at the same speed.


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Ambient noiseis a frequent result of road transportation in urbanareas. The addition of all the noise generated by cars, trucks andbuses creates a permanent ambient noise (ranging from 45 to 65 db)that impairs the quality of life in urban areas and thus the property

values of residences. Nearby road arterials, ambient noiseis replacedby direct noise and vibrations. The acoustics created by thesurrounding environment (hills, buildings, trees, open space, etc.)alleviate or worsen local conditions.

Noise level grows arithmetically with speed. For instance a car

traveling at 20 km/hr emits 55 db of rolling noise, at 40 km/hr 65 db, at80 km/hr 75 db and at 100 km/hr 80 db. Available evidence underlinesthat around 45% of the population in developed countries live in highlevels of noise intensity (over 55 db) generated by road transportation.

Along major highway arterials in inter-urban areas, noise emissions arelikely to alter the living environment of wildlife species.


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Rail Transportation Noise

Rail accounts for 10% of total noise emissions bytransportation. Noise comes from the engine (mostlydiesel), the friction of wheels over the rails, and whistleblowing. Furthermore, when trains are moving at high

speed, aeroacoustic (a branch of acoustics that studiesnoise generation via either turbulent fluid motionor aerodynamic forces interacting with surfaces)noisebecomes more important than other sources.Depending of the train aerodynamics, noise emissions are

from 50 to 80 times the logarithm of train speed andbecome significant at speeds higher than 200 km/hr.


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When rail / truck transshipment is involved, theconvergence of trucks towards rail yards provides anadditional source of noise related to rail transportationactivities.

Around 3% of the population may be exposed to high noiselevels from rail transportation in OECD countries. The levelof exposure is obviously related to the importanceand location of rail transportation infrastructure. The mostimportant noise impacts of rail operations are in urbanareas where the majority transshipment functions areperformed. Furthermore, rail terminals are often located inthe central and high density areas of cities.


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Air Transportation Noise

Air transportation accounts for 20% of total noise

emissions by transportation. As air transportation took a

growing importance in inter-city transportation and that jet

engines were predominantly used, noise emissions have

increased significantly to the point of becoming a major

concern near airports.


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Noise comes from thejet engine, the aerodynamicfrictionand ground craft operations. Even if the turbofanis the least noisy jet propulsion technology available,aircrafts are an acute source of noise in several urbanareas. Noise from aircraft operation is known tohave direct impact on property values around airports.This effect is distributed along major approach and take offlanes.

The establishment of heavily used flight paths betweenmajor cities creates noise corridors where ambient noise isalmost prevalent. This is particularly noted when thosecorridors are over densely populated areas.


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Intensity measurements and

monitoring The loudness of noise is measured by decibels (db). Decibel scales

are logarithmic rather than linear. Thus, the change from 40 db (alibrary) to 80 db (a dishwasher or garbage disposal) represents a ten-thousandfold increase in sound loudness.

The frequency or pitch of a sound is also a factor in determining itsdegree of harm. High pitched sounds are the most annoying.

The most common sound pressure scale for high pitched sounds is theA scale, whose units are written dbA. Hearing loss begins withprolonged exposure (eight hours or more per day) to 80 or 90 dbA

levels of sound pressure. Sound pressure becomes painful at around140 dbA and can kill at 180 dbA.


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Intensity of noise

Sound of source Intensity in decibels

Jet craft at take off 145

Pain occurs 140

Hydraulic pressure 130

Jet airplane (160m overhead) 120

Unmuffled motorcycle 110

Subway train 100 Farm tractor 98

Gasoline lawnmower 96

Food blender 93

Heavy truck (15m away) 90

Heavy city traffic 90

Vaccum cleaner 85

Hearing loss after long exposure 85 Garbage disposal unit 80

Diswasher 65

Window air conditioner 60

Normal speech 60


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Impacts of noise pollution

PHYSIOLOGICAL EFFECT

If sound waves consist of regular vibrations it is oftenjudged to be pleasing, whereas random wave forms are

experienced as noise. Excessive noise results in hearingbecoming dull and decreased hearing sensitivity. Thiseffect is at first temporary and should the person remain ina quiet environment their hearing soon recovers. Exposureto very loud noise or repeated exposure to more moderatenoise may result in permanent hearing loss. Inducedhearing loss can be prevented but can never be cured. Thedanger is that a person may not perceive the noise to be aproblem, but may already have experienced hearing loss.


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PSYCHOLOGICAL EFFECTS

Noise can create a stress response in humans, affectingthe endocrine, nervous, digestive, and cardiovascular

systems. Adaptation and habituation can occur, butprolonged exposure may lead to any of the diseases ofadaptation, including digestive and cardiovascularproblems (Veitch, 1995).

Noise that affects feelings and reactions has apsychological effect on humans. This normally occurs atnoise levels that do not cause a physical effect.

Annoyance, stress and hypertension are symptoms of thepsychological impacts of noise pollution.


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COMMUNICATION

Noise levels interfere dramatically with communication

that may often lead to a loss in productivity.


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TIREDNESSAND HEADACHES

Tiredness and headache can often be traced back to

exposure to continuous unpleasant noise levels.


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OCCUPATIONAL NOISE

This can result in tiredness, headaches, reduced

productivity, and in severe cases can result in prolongedhearing loss. The effect however is related to factors such

as the loudness, pitch, predictability, and controllability of

the noise as well as the age, gender and exposure duration

of the person affected (Veitch, 1995).

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