Additional information
ENVIRONMENTAL STUDIES
Additional information
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Measurements of noise pollution: Noise is measured in “decibel”. Decibel levels of common sounds.
Decibel
|
Environmental condition
|
0
|
Threshold of hearing
|
10
|
Rustle of leaves
|
20
|
Broadcasting studio
|
30
|
Bedroom at night
|
40
|
Library
|
50
|
Quiet Office
|
60
|
Conversational speech (at 1 m)
|
70
|
Average radio
|
74
|
Light traffic noise
|
90
|
Subway train
|
100
|
Symphony orchestra
|
110
|
Rock band
|
120
|
Aircraft take off
|
146
|
Threshold of pain
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- Below a sound level of 80db hearing loss does not occurs.
- 1 hour exposure to a 100db sound level can produce a “temporary threshold limit”.
- Exposure to 95db for 8 hours every day for a period of 10 hours may cause about 15db of “noise-induced permanent threshold limit”.
Permitted noise levels:
Zone
|
Day – time db
|
Night – time db
|
Silent zone
|
50
|
40
|
Residential zone
|
55
|
45
|
Commercial zone
|
65
|
55
|
Industrial zone
|
70
|
70
|
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Last modified: Monday, 2 January 2012, 7:24 AM