MIDTERM QUIZ 2 - Noise Pollution

sound

a vibration that propagates as a mechanical wave of pressure and displacement through some medium

noise

• is basically any unwanted sound

• it is measured in dB units

characteristics of noise

• sound pressure

• frequency

• duration

• time of the day

• location

• intermittency

kinds of noise

• continuous

• variable

• intermittent

• impulse or impact

• chemical & instrumental

variable noise

• manufacturing & construction noise

• different operations or different noise sources cause the sound changes over time

impulse noise

• is a category of noise which includes unwanted, almost instantaneous sharp sounds

• caused by electromagnetic interference, scratches on the recording disks, & ill synchronization in digital recording & communication

continuous noise

is noise which remains constant & stable over a given time period

intermittent noise

if there is a mix of relatively quiet & noise period

noise pollution

• refers to a type of energy pollution in which distracting, irritating, or damaging sounds are freely audible

• in this type of pollution, contaminants are not physical attributes, but waves which interfere with the naturally occurring waves of a similar type in the same environment

sources of noise pollution

• household sources

• social events

• commercial & industrial activities

• transportation

sources of industrial noise

• construction activities

• noise created by

• agricultural equipment

• manufacturing industries

household

is an industry in itself and is a source of many indoor noises

sources of indoor noise

• entertainment equipment in the house

• Domestic gadgets

hearing problems

reduces our sensitivity to sounds that our ears pick up unconsciously to regulate our body’s rhythm

health issues

Excessive noise pollution in working areas and even in our homes can influence psychological health

cardiovascular noises

High intensity noise causes high blood pressure and increases heart beat rate as it disrupts the normal blood flow

how to control noise pollution

• control at source

• control in the transmission path

• using protective equipment

noise control techniques

• sound insulation

• sound absorption

• vibration damping

• public education & awareness

noise

• derived from the Latin word “nausea“

• Unwanted sound

• originates from human activities, especially the urbanization

• increasingly omnipresent, yet unnoticed form of pollution

• Could come from vehicles

characteristics of sound

• frequency

• sound level (pitch)

frequency

• function of the sound’s wavelength and the transmitting medium and is expressed as:

  • f = v / λ

• has 3 zones

3 zones of frequency

1. infrasonic

2. audible

3. ultrasonic

categories of sound

1. wide band

2. narrow band

3. impulse

wide band

wide range of frequencies

narrow band

narrow range of frequencies

impulse

a temporary sound that may or may not be repetitive

most significant sources of damaging noise

1. occupational music

2. loud music

3. airports

sound pressure level

measured as dB

sound level

• dB(A)

• filtered soun

measuring devices for sound

1. sound pressure level meter

2. sound level meter

3. audiometer

soung pressure level meter

• measures sound as a flat response

• dB

sound level meter

• measures the filtered sound, dB(A)

• Some very low – frequency sound and much of the very high - frequency sound are filtered by the meter and the measured sound represents the hearing of human ear

audiometer

measures the hearing ability at various frequencies producing an audiogram

general effects of noise

• hearing loss

• heart disease

• sleep disruption

• mental & social well-being

• danger to people

effects of noise on human health

1. Very loud impulse can burst the ear drum, causing mostly temporary loss of hearing

2. A torn ear drum heals poorly and can result in permanent damage

3. The bones in the middle year are not usually damaged by loud sounds but they can be hurt by infections

4. Middle ear infection can be debilitating, since our sense of balance depends on middle ear

5. Very loud sounds will stun the hair cells and cause them to cease functioning though most of the time, temporary and can be healed with

   time

6. When the insult to the ear is prolonged, the damage can be permanent and cannot be corrected by hearing aids

7. Permanent damage to young people is inflicted by most frequently loud music

8. Loud music does more than cause permanent damage, it is, in the Darwinian sense, synonymous to danger

9. The human body reacts to loud noise as to protect itself from imminent danger

10. The bodily reactions include the following:

    • the eyes dilate

    • adrenaline flows

    • blood vessels dilate

    • heartbeat is altered

    • senses are altered

    • blood thicken

11. Noise cause other ailments such as nervous tension, headaches to neuroses

12. Noise also disturbs unborn children, and sometimes

    cause seizures in epileptics

13. People who live and work in noisy environments have measurably greater general health problems, are grouchy and ill – tempered and have trouble concentrating

14. Noise that deprives one of sleep carries with it an additional array of health problems

15. Most importantly, we cannot adapt to high noise levels

OSHA

• Occupational Health and Safety Act

• the most effective single legislation to pass congress in the noise control area

Regulations Promulgated by OSHA

• Limits of industrial noise

• Sound levels greater than 115 dB(A) are clearly detrimental and should not be permitted

• Industrial noise is mostly constant over an 8 – hr working day

• Community noise is intermittent noise.