MUHAMMAD FAHAD ANSARI 12IEEM 14

1. Noise pollution
MUHAMMAD FAHAD ANSARI
12IEEM 14

2. Loudness of sound
=> The level of sound.
- measuring unit: decibel
written as dB
- The higher the decibel, the louder
is the sound.
- Can be measured with a decibel
meter

3. - The following photos show two different
kinds of decibel meters:

4. Sound level and human’s perception
sound
perception level (dB) example
– 100
– 80
– 60
– 30
quiet soft whisper (25 dB)
very quiet sound – 10 breathing sound (10 dB)
–the lowest sound level that can be heard
0

5. Sound level and human’s perception
sound
perception level (dB) example
– 100
– 80
normal conversation (60 dB)
– 60
acceptable soft conversation in
– 30 libraries (30 dB)
quiet
– 10 soft raining (50 dB)
– 0

6. Sound level and human’s perception
sound
perception level (dB) example
– 100
annoying
– 80 alarm clock (80 dB)
noisy busy traffic (70 dB)
– 60
acceptable
– 30
quiet
– 10
– 0

7. Sound level and human’s perception
sound
perception level (dB) example
very noisy
damage our
ears
– 100 crying baby (100 dB)
annoying passing train (90 dB)
– 80
noisy
– 60
acceptable
– 30
quiet
– 10
– 0

8. Sound level and human’s perception
sound
perception level (dB) example
road drilling
very noisy (120 dB)
damage our
ears disco (110 dB)
– 100
annoying
– 80
noisy
– 60
acceptable
– 30
quiet
– 10
– 0

9. Sound level and human’s perception
sound
perception level (dB) example
very noisy rocket taking off (190 dB)
jet plane taking
damage our
ears
off (130 dB)
– 100
annoying
– 80
noisy
– 60
acceptable
– 30
quiet
– 10
– 0

10. We can enjoy some sounds as music.
However, sound can also be
annoying noises.

11. Noise
=> annoying sound
- Noise is a kind of pollution.
pollution
It is a common problem in
crowded cities.

12. There are many people but less
space in Hong Kong. We live in a
densely-populated city.
Noise pollution is serious.

13. Can you give some examples of
sources of noise Pakistan?
repairing
construction site house
busy traffic playing
movies
road drill
playing hi-fi
taking off and
burglar
landing of plane
alarm

14. - There are many loud sounds in our
surroundings, including some of the
objects we often use.

15. Effects of noise pollution
- causes mental stress
- increases the heartbeat rate and
blood pressure
- disturbs our sleep
- makes us difficult to concentrate,
so accidents happen more easily
- annoying, makes us
become bad tempered
more often

16. e.g. restaurants
- Hearing sound level at 80 dB for a long time,
=> may cause temporary or permanent
damage to our ears.
- Hearing sound level at 130 dB makes
our ears feel pain,
pain
=> because the eardrum vibrates
too vigorously.
- When sound level reaches 150 dB,
dB
=> causes damage to the
eardrum or ear bones,
make us go deaf.

17. According to an investigation done by a
group in 1998:
Wear headphones to listen to music for
more than 6 hours a week, the sense of
hearing will decrease by 30 years.

18. How can noise pollution
be controlled?
controlled

19. Protecting our ears
1 Avoid listening to loud music for
a long time.
2 Stay away from noisy places.
e.g. disco, karaoke centre…
3 Wear ear protectors
when working at
noisy places

20. We should wear an
ear protector when
working at a noisy
place
The employer cannot request
employees to work in a place at sound
level higher than 90 dB for more than
8 hours without break.

21. Noise control
- government has taken some measures
to control noise:
- It is an offence to make loud noise
between 11 p.m. and 6 a.m.

22. Pile drive Road drill
public holidays Noisy construction
works (including pile
between 7 p.m. drive and road drill)
and 7 a.m. are not allowed
on weekdays without a permit.

23. - Schools in noisy environment are
given special funding to install
air-conditioners in their classrooms.
- Residential areas close to the highways
are protected by noise barriers.

24. as responsible citizens, we
have the responsibility to
help reduce noise pollution.

25. People with eye defects or ear defects
are also part of the society.
They need our support and love.
love
How can we
help them?