1. Noise Noise pollution in Hong Kong road drilling busy street traffic
jet plane taking off

2. Sound intensity level (or sound level) is measured in decibels (dB).
A sound wave of higher sound intensity level generally sounds louder.
threshold of hearing
= lowest sound intensity level that we can hear
= 0 dB
10 dB increase in sound intensity level
intensity of sound is 10 times stronger

3. Sound intensity level / dB
Sound intensity levels of some sounds:
Sound
Sound intensity level / dB
Effects
Threshold of hearing
Barely audible
Whisper 20 -
Classroom - 35
Quiet home 50 -
Conversation at 0.5 m 65 -
Busy street traffic 85 -

4. Sound intensity level / dB Effects
Hearing damage after long exposure
Loud music
80 – 100
Rock concert
115 – 120
Painful to ears, permanent hearing damage
Road drilling
120
Jet plane at 30 m
140
Immediate permanent hearing damage
Space shuttle engine
200

5. Controlling noise pollution
Measures taken by the Environmental Protection Department (EPD)
The noise control ordinance control noise produced at construction sites.
Barrier are built to block traffic noise.

6. Buffer area separates the residential area from busy roads
Pedestrian schemes reduce traffic noise to nearby residents at night.

7. Things we can do We should wear ear protectors in noisy environments.
Avoid exposure to loud music for a long time.

8. It is an offence to generate excessive noise between 11 p. m. and 7 a
It is an offence to generate excessive noise between 11 p.m. and 7 a.m. or on a public holiday.

9. That’s the end of Section 16.6
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