Noise

The Noise Pollution The Noise Pollution is a type of energy pollution in which distracting, irritating, or

damaging sounds are freely audible.

As with other forms of energy pollution (such as heat and light pollution), noise pollution contaminants are not physical

particles, but rather waves that interfere with naturally-occurring waves of a similar

type in the same environment.

In simple words the In simple words the

Noise Pollution can be defined Noise Pollution can be defined like the excess of sound that like the excess of sound that

disrupts the normal conditions of disrupts the normal conditions of the environment in a certain the environment in a certain

area. area.

While the noise does not accumulate, moved or maintained at

the time as the others types of pollutions, can also cause negative effects –

- physiological, - psychological,

- economic, - socially

speaking to the quality of life if it is not controlled properly.

Sounds are considered noise pollution if they adversely affect wildlife, human activity, or are capable of damaging

physical structures on a regular, repeating basis.

In the broadest sense of the term, a sound may be considered noise pollution if it disturbs any natural process or causes

human harm, even if the sound does not occur on a regular basis.

The decibel (dB) is a measure of sound intensity; that is, the magnitude of the

fluctuations in air pressure caused by sound waves.

The decibel scale is logarithmic, not arithmetic. This means that a doubling of

sound intensity is not represented as a doubling of the decibel level.

Decibels are usually measured with a filter that emphasizes sounds in certain

frequencies.

The "A" filter (dBA) is the one most frequently used.

The "C" filter (dBC) puts more weight on low-frequency sounds such as the bass in

amplified music. Normal conversation is around 60 dB. Noise of less than 75 dB, even for long

periods is unlikely to damage your hearing.

The Noise pollution can affect The Noise pollution can affect both your health and well being both your health and well being

in in several different ways.several different ways.

Effects Of Noise On Humans

1. Auditory effects interfering with hearing; auditory fatigue and deafness.

2. Non-auditory effects interfering with social behaviour; problems with communications, sleep, recreation, mental equilibrium (peace), and the

ability to concentrate at work

3. Physiological effects affecting biological functions; anxiety,

neurosis, insomnia, dizziness, nausea, fatigue, visual symptoms,

hypertension, cardiovascular symptoms, liver changes, nervous symptoms, changes in skin, fast

irregular heart beats (tachycardia).

4. Endocrine and hormonal changes relating to stress and noise levels.

i.e. raised adrenaline and cholesterol.

Noise causes blood vessels to close cutting down blood supply to the

fingers and toes. Respiratory changes occur due to

noise.

5. Psychological effects - physical and mental fatigue, loss of concentration,

lower efficiency, reduced output, absenteeism, higher rates of accidents, behavioural changes, errors at work,

loss of sleep, psychosomatic disorders, diseases related to stress, mental

illness, aggravation of existing stress problems and mental illness, neurotic

effects, rage anger, crime.

However, as more and more research are being done, more serious health risks have developed due

to the increase in noise pollution.  - Hearing loss (conductive or sensorineural)

- Hypertension - Aggressive behavior

- Serious sleep loss - Heart disease (stress related)

- Danger to people - cover warning signals &: Cause accidents

Changes in the Changes in the immune system and birth immune system and birth defectsdefects have been attributed to noise  have been attributed to noise

exposure, but evidence is limited. exposure, but evidence is limited.

Although some presbycusis may occur Although some presbycusis may occur naturally with age, in many developed naturally with age, in many developed

nations the nations the cumulative impact of noise is cumulative impact of noise is sufficient to impair the hearing of a large sufficient to impair the hearing of a large fraction of the populationfraction of the population over the course over the course

of a lifetime. of a lifetime.

Beyond these effects, elevated noise Beyond these effects, elevated noise levels can create stress, increase levels can create stress, increase workplace accident ratesworkplace accident rates, and , and

stimulate aggression and other anti-stimulate aggression and other anti-social behaviors. social behaviors.

The most significant causes are The most significant causes are vehicle and aircraft noisevehicle and aircraft noise, prolonged , prolonged

exposure to loud music, and exposure to loud music, and industrial noiseindustrial noise. .

Cardiovascular effectsCardiovascular effectsNoise has been associated with important Noise has been associated with important

cardiovascular health problems. In 1999, the cardiovascular health problems. In 1999, the WHO concluded that the available evidence WHO concluded that the available evidence

showed a weak association between long-showed a weak association between long-term noise exposure above 67-70 dB(A) and term noise exposure above 67-70 dB(A) and hypertensionhypertension. Recent studies have suggested . Recent studies have suggested

that noise levels of 50 dB(A) at night may that noise levels of 50 dB(A) at night may also increase the risk of also increase the risk of myocardial myocardial

infarctioninfarction by chronically  by chronically elevating cortisol productionelevating cortisol production

Industrial noise is usually considered mainly from the point of view of

environmental health and safety as sustained exposure can cause permanent hearing damage.

Traditionally, workplace noise has been a hazard linked to heavy

industries such as ship-building and associated only with noise induced

hearing loss (NIHL).

Modern thinking in occupational safety and health identifies noise

as hazardous to worker safety and health in many places of

employment and by a variety of means.

Noise also acts synergistically with other hazards to increase the risk of harm to workers. In

particular, noise and dangerous substances (e.g. some solvents) that have some tendencies

towards ototoxicity may give rise to rapid ear damage.

A-weighted measurements are commonly used to determine noise levels that can cause harm to the human ear, and special exposure meters are

available that integrate noise over a period of time to give an Leq value (equivalent sound

pressure level), defined by standards.

No one on earth can escape the sounds of noise.

In the past thirty years, noise in all areas, especially in urban areas, have been

increasing rapidly.

There are numerous effects on the human environment due to the increase in noise

pollution.

Noise can have a negative effect on humans, domestic and wild animals, ecological systems, buildings and other structures.EffectPhysical effects from noise include: vibration to buildings, damage to glass windows, plaster cracking, damage to building foundations. Jet aircraft have damaged roads

and buildings.

Acoustic PollutionSeveral years ago in the protection

regulations of the environment noise was not considered to be the pollutant. Then in all the

countries of the world there have been elaborated procedure and bylaws that they

entrust of the protection of the environment against the excess of noise. The most serious efforts of the international communities are

translated in policies of prevention and control of the sonorous pollution.

1. First, we must determine whether the noise whether the noise level is such that it causes loss of auditionlevel is such that it causes loss of audition. To

do it, comparing measurements made with established norms, which indicate noise level by activity and exposure times, partners both are taken corrective action to reduce harmful

levels of noise.2. It is known that a noise level below 85dB (A) noise level below 85dB (A)

does not cause harm to the employeedoes not cause harm to the employee. However, it can be very annoying, depending on

the activity taking place.

3. If it is established that the noise is generated by a machine, we should see

how to modify it, so it produces less noise.

Sometimes lowering its speed is sufficient.

You can also make a total closure of the machine, or you can exchange it

for another quieter.

4. If after applying the earlier recommendation, the discomfort by the noise

persists, provision for workers protective equipment such as earmuffs and ear plugs

should be done. Important is to ensure that workers use the

equipment properly, motivating and monitoring their use, particularly when the

noise level may injure over time, their hearing ability.

5. If the walls of the compound are harsh acoustically, it will produce echoes and reflections, which will

increase the sound pressure. In this case, we should seek absorbent

materials for coating the walls, especially if there are machines located

close to these walls. This will reduce the sound pressure.

Noise-canceling headphonesThese reduce unwanted ambient sounds (i.e.,

acoustic noise) by means of active noise control (ANC). Essentially, this involves using a microphone, placed near the ear,

and electronic circuitry which generates an "antinoise" sound wave with the opposite polarity of the sound wave arriving at the microphone. This results in destructive

interference, which cancels out the noise within the enclosed volume of the headphone.

Possible Solutions•Auditory personalized Auditory personalized

protectionprotection •Absorbent materials•Acoustics barriers•Isolations

Personal ProtectionIt constitutes one of the most efficient methods

and simultaneously economic. It is a question of the auditory stoppers It is a question of the auditory stoppers

called (or acoustic shells), that they have the called (or acoustic shells), that they have the ability to reduce the noise in almost 20 dBability to reduce the noise in almost 20 dB, which allows that the person who uses them could be located in very noisy environments

without any problem. Very used by the workmen and other workers

of some noisy industries.

VIBRATION VIBRATION

DEFINITIONDEFINITION• VIBRATION IS OSCILATORY MOTION

• A CYCLE OF SPECIFIC ACTIVITY BACK-FORTH, UP AND DOWN RESULTING FROM REVERSAL OF ENERGY

• FREQUENCIES OF 100 HZ OR HIGHER ARE ABSORBED BY THE HANDS AND WRISTS

• FREQUENCIES UNDER 100 HZ ARE ABSORBED BY THE UPPER LIMB JOINTS

RESPONSE DEPENDS ON:RESPONSE DEPENDS ON:• FREQUENCY OF VIBRATION

• AMPLITUDE OF VIBRATION

• TIME HISTORY TIME HISTORY OF VIBRATION EXPOSUREEXPOSURE

• DIRECTIONDIRECTION OF VIBRATION

• POINT OF APPLICATION POINT OF APPLICATION OF VIBRATION

• HOW MUCH HOW MUCH VIBRATION IS TRANSMITTED

• AFFECT OF CLOTHING AND EQUIPMENTCLOTHING AND EQUIPMENT

• BODY SIZE BODY SIZE (HEIGHT AND WEIGHT)

• BODY POSTUREBODY POSTURE/ BODY TENSION

MAGNITUDE IS INFLUENCED BY:MAGNITUDE IS INFLUENCED BY:• TYPE, WEIGHT, AND CONDITION OF TOOL

• ACCELERATION AND FREQUENCY ACCELERATION AND FREQUENCY PRODUCED BY TOOL– TOOL TYPE, ENVIRONMENTAL, ANTI-VIBRATION

MATERIAL

– OPERATING SPEED, ERGONOMICS OF USE

• GRIPPING FORCESGRIPPING FORCES

• ORIENTATION AND POSTURE ORIENTATION AND POSTURE OF THE HANDS, ARMS, AND BODY DURING WORK

• PARTS OF HANDS IN DIRECT CONTACT PARTS OF HANDS IN DIRECT CONTACT WITH THE VIBRATING SURFACE

TYPESTYPES

• WHOLE BODY VIBRATION

• SEGMENTAL (HAND-ARM) (HAND-ARM) VIBRATION

WHO’S AT RISK?WHO’S AT RISK?• ANYONE WHO ABSORBS MACHINE

VIBRATION THROUGH THEIR HANDS AND ARMS WHILE WORKING A FAST-MOVING HAND TOOL --

• OR THROUGH THE BUTTOCKS AND THE SOLES OF THE FEET WHILE RIDING IN OR STANDING NEAR VIBRATING, HEAVY MACHINERY--

• RUNS THE RISK.RUNS THE RISK.

HOW MANY EXPOSEDHOW MANY EXPOSED• APPROXIMATELY 1.2 MILLION EXPOSED

• 50 - 60 % OF WORKER POPULATION HAVE SYMPTOMS

TOOLS MOST COMMONLY TOOLS MOST COMMONLY ASSOCIATED:ASSOCIATED:

• POWERED HAMMERS

• CHISELS, CHAIN SAWS

• SANDERS, GRINDERS, RIVETERS

• BREAKERS, DRILLS, COMPACTORS

• SHARPENERS, SHAPERS

WHAT IS VIBRATION SYNDROMEWHAT IS VIBRATION SYNDROME

• VASOSPASTIC, NEUROMUSCULAR, ARTHRITIC DISORDERS OF THE HANDS AND UPPER LIMBS

• COMPOSITE OF VIBRATION INDUCED SIGNS AND SYMPTOMS (e.g. NUMBNESS, TINGLING OF THE FINGERS, EPISODIC BLANCHING OF THE FINGERS, PAIN, REDUCED GRIP STRENGTH AND DEXTERITY

• RAYNAUD’S SYNDROME, WHITE FINGER

SYMPTOMS OF VIBRATION SYMPTOMS OF VIBRATION SYNDROMESYNDROME

• DISCOMFORT FROM COLD

• TINGLING, NUMBING

• BLANCHING FINGERS

• PAIN

CONTROL STRATEGIESCONTROL STRATEGIES:• ENGINEERING AND WORK PRACTICES

• ANTI-VIBRATION CLOTHING, EQUIPMENT AND TRAINING

• GOALS:

– REDUCE THE INTENSITYINTENSITY

– REDUCE THE EXPOSURE DURATIONEXPOSURE DURATION

– IDENTIFY THE EARLY SIGNS AND EARLY SIGNS AND SYMPTOMSSYMPTOMS

ENGINEERING CONTROLS:ENGINEERING CONTROLS:

• REDUCTION AT SOURCESOURCE

• REDUCTION OF TRANSMISSIONTRANSMISSION

• PROCESS MODIFICATIONMODIFICATION

REDUCTION AT SOURCEREDUCTION AT SOURCE

• REDUCE SPEEDSPEED OF TOOL

• REDUCE WEIGHT AND POWER WEIGHT AND POWER NEEDED TO DRIVE THE TOOL

• CHANGE TYPE TYPE OF TOOL– E.G. RECIPROCATING ENGINE TO ROTARY OR ELECTRIC MOTOR

• TOOL MAINTENANCEMAINTENANCE

• MOUNT EQUIPMENT ON SPRINGS OR COMPRESSION PADS

• USE MATERIALSMATERIALS THAT GENERATE LESS VIBRATION

REDUCTION AT TRANSMISSIONREDUCTION AT TRANSMISSION• PROVIDE CUSHION TO ACT AS A CUSHION TO ACT AS A

VIBRATION ISOLATER VIBRATION ISOLATER IN A SEATED TASK• PROVIDE ANTI-FATIGUE MATS ANTI-FATIGUE MATS FOR

STANDING OPERATION• DESIGN TOOLS DESIGN TOOLS TO REDUCE VIBRATION

TRANSMITTED TO THE HANDS, • COUNTER WEIGHT TOOLS WEIGHT TOOLS TO MINIMIZE

GRIPPING REQUIRED TO OPERATE THEM– DAMPENING MATERIALS AND GLOVES ARE DAMPENING MATERIALS AND GLOVES ARE

USUALLY MORE EFFECTIVE FOR HIGHER USUALLY MORE EFFECTIVE FOR HIGHER FREQUENCIES.FREQUENCIES.

PROCESS MODIFICATIONPROCESS MODIFICATION• CHANGES IN ANY ASPECT OF PROCESS

TO ELIMINATE NEED FOR VIBRATING TO ELIMINATE NEED FOR VIBRATING TOOLS OR EQUIPMENTTOOLS OR EQUIPMENT

• USING MECHANICAL AIDS (CHUCKS, CLAMPS) TO HOLD MATERIAL– REDUCES TIME OR INTENSITY OF EXPOSUREREDUCES TIME OR INTENSITY OF EXPOSURE

• ROBOTICSROBOTICS

• AUTOMATIONAUTOMATION

• SUBSTITUTIONSUBSTITUTION OF MATERIALS– PLASTICS FOR HARD METALPLASTICS FOR HARD METAL

WORK MODIFICATION WORK MODIFICATION APPROACHESAPPROACHES

• LIMIT NUMBERS OF HOURS HOURS

• REDUCE NUMBER OF DAYS PER OF DAYS PER WEEKWEEK

• ROTATE ROTATE BETWEEN VIBRATING AND NON-VIBRATING TOOL TASKS

• SCHEDULE MAINTENANCE BREAKSBREAKS

WORK PRACTICESWORK PRACTICES• LENGTH LENGTH OF WORK DAY

• JOB ROTATION ROTATION

• SELECT LOW VIBRATION TOOLSLOW VIBRATION TOOLS

• DESIGN WORK TASK AND WORKPLACE ERGONOMICALLYERGONOMICALLY

• REDUCE GRIP FORCE GRIP FORCE APPLIED

• REDUCE FORCEFORCE APPLIED

• RESTRICT USE OF PIECE WORK AND RESTRICT USE OF PIECE WORK AND INCENTIVE PAYINCENTIVE PAY

• ERGONOMIC WORK POSTURESPOSTURES

ADMINISTRATIVE CONTROLSADMINISTRATIVE CONTROLS• PPE PPE TO REDUCE TRANSMISSION OF

VIBRATING ENERGY TO THE HAND

• PROTECT AGAINST EXPOSURE TO COLD COLD AND TRAUMAAND TRAUMA

• TRAININGTRAINING– SOURCE OF VIBRATION– ADVERSE HEALTH AND SAFETY EFFECTS – EARLY SIGNS AND SYMPTOMS– USE AND AVAILABILITY OF VIBRATION PROTECTIVE CLOTHING– ANTI-VIBRATION DEVICES– VALUE OF GOOD TOOL MAINTENANCE– WORK PRACTICE PROCEDURES

• Infrasound refers to waves or vibrations with a frequency below the audibility range of the human ear (i.e. < 20 Hz). Hence, these waves cannot be heard by humans.

• They can be felt and, as studies have shown, they produce a range of effects in some people including anxiety, extreme sorrow, and chills.

• Infrasonic waves can carry over long distances [thousands of kilometres] and are less susceptible to disturbance or interference than waves of higher frequencies.

• Infrasound may be produced by wind, types of earthquakes, ocean waves, and certain things such as avalanches, volcanoes, and meteors etc…

• Infrasound is especially dangerous, due to its strong vibrations, or oscillations.

• They hug the ground, travel for long distances without losing strength, and are unstoppable.

• Furthermore, not much amplitude is needed to produce negative effects in the human body.

• Therefore, even mild infrasound exposure requires several hours, or even days, to reverse the resulting symptoms.

• Waves of infrasound are invisible, but they slam into living tissues and physical structures with great force.

The sensation vibrates internal organs and buildings, flattening objects as the sonic wave strikes.

At certain pitches, it can explode matter.

EXAMPLESEXAMPLES• Natural explosions from volcanoesNatural explosions from volcanoes produce

infrasonic waves. When Krakatau exploded, an entire island was lifted 100 miles into the air, and windows were shattered 1,000 miles away from ground zero. The shock waves, affecting both earth and atmosphere, continued for hours.

• Explosives, such as atomic weaponsExplosives, such as atomic weapons, produce infrasound. Zone one is ground zero and its destruction. Zone 2 is a powerful, speeding, sonic wave of reduced air pressure. This concussion blast travels at great distances away from ground zero and few survive its destructive path.

Uses of infrasound:Uses of infrasound:

1. Medical: (therapeutic devices) - Several studies conducted in Russia and

Europe reported that infrasound has therapeutic effects.

- Infrasound peumomassage: At 4 Hz, the progression of myopia in school children can be stabilized.

- Infrasound phonophersis in antibacterial drugs: In treatment of patients with bacterial keratitis, it is as effective as local instillations of the same drugs.

2. Monitoring activities of the atmosphere:

- Infrasonic waves will be influenced by the atmosphere during its propagation, which is closely related with the distribution of temperature and wind in the atmosphere.

- By measuring the propagation properties of infrasonic waves generated by natural sources, one can detect some characteristics and rules of the large scale meteorological motions.

3. Forecasting natural disasters: 3. Forecasting natural disasters: Many disasters, such as volcanic eruptions, earthquakes, land-slides and clear-air turbulences, radiate infrasound in advance. By monitoring the infrasound waves, we can forecast these disasters.

FUN FACTS!FUN FACTS!Elephants have the ability to emit

infrasound to communicate at distances of up to 10 miles (12 - 35 Hz.). Even tigers emit infrasound.

“Odd sensations that people attribute to ghosts may be caused by infrasonic vibrations” --Psychologist Richard Wiseman of the University of Hertfordshire

• High-frequency sound waves that is above the audibility range of the human ear [approximately 22kHz]; Wavelength of about 1.5 mm

• Sound cannot be heard but can be emitted and detected by special machines

• The speed of ultrasound does not depend on its frequency; it depends on what material or tissue it what material or tissue it is travelling inis travelling in.

Both the mass and spacing of the molecules and the attracting force between the particles of the material have effects on the speed of the ultrasound as it passes through.

How does ultrasound work and how to How does ultrasound work and how to produce images of ultrasound?produce images of ultrasound?

• Ultrasound waves images are produced by a transducer.

• A transducer is a device that takes power from one source, converts the energy into another form, and delivers the power to another target.

• In this case, the transducer acts as a acts as a loudspeaker or a microphone, it converts loudspeaker or a microphone, it converts electrical signals to ultrasound waves, and electrical signals to ultrasound waves, and picks up the reflected waves, converting them picks up the reflected waves, converting them back into electrical signals. back into electrical signals.

• The electrical signals returned to the transducer are used to form pictures on a television screen.

• Ultrasound travels faster in dense travels faster in dense materials and slower in compressible materials and slower in compressible materialsmaterials. In soft tissue sound travels at 1500 m/s, in bones about 3400 m/s, and in air 330 m/s.

• Travels freely through fluid and soft Travels freely through fluid and soft tissuestissues but is reflected back as 'echoes' but is reflected back as 'echoes' when it hits a more solid/dense surfacewhen it hits a more solid/dense surface

• When the ultrasound 'hits' different structures in the body of different density, it sends back echoes of varying strength

Uses of ultrasound: Uses of ultrasound: 1. Medical:1. Medical: • sonography:sonography: Ultrasound waves can be bounced

off of tissues using special devices. The echoes are then converted into a picture called a sonogram.

• Ultrasound is often used to examine a foetus during pregnancy, or a fatal heart.

• Ultrasound usually ranges from one MHz (one million cycles per second) to 20 MHz. This is because tissues absorb higher frequency energy more readily, hence producing fainter images.

• Pulse echo visualization:Pulse echo visualization:

• The information of objects is obtained by using discrete lines of sight, with the transducer position and orientation which defines the line of sight and the delay of received echoes, which is used to determine the range of the echo-producing object.

• It can be used in a wide range of clinical conditions and is useful in many parts of the body.

• There are 3 modes of the pulse echo visualization (i.e. A-mode, M-mode, and B-mode)

• Doppler effect: Doppler effect: • Ultrasound based diagnostic imaging technique can

be enhanced with Doppler measurements, which employ the Doppler effect to assess whether structures (usually blood) are moving towards or away from the probe, and its relative velocity.

• The principal applications of Doppler effect are in cardiac and peripheral vesicular diagnostic specialties. Current qualitative applications involve 2 aspects of blood flow evaluation. Doppler devices are primarily concerned with the detection and evaluation of blood flow disturbances resulting from valves and septal defects.

2. In animals:

• For navigation:

Bats use ultrasound for navigation. They send out ultrasounds and judges the distance of objects ahead of them, or what the objects are, by the received echoes. This allows them to catch flying insects while flying full speed in pitch darkness.

Communication:

• Whales make use of ultrasounds for communication purposes. Individual pods of whales have their own distinctive dialect of calls, similar to songbirds.

• Singing whales are usually solitary males who exhibit it in a shallow smooth-bottomed area where sound propagates well. They are interpreted as territorial and mating calls.