Noise
Causes
When inside at home most people reported that noise was greatest from appliances, TV, music, traffic, and the greatest source of this noise nuisance was their neighbours.
When outside most people reported noise from appliances and traffic. Other major sources of noise are aircraft and children.
Some familiar noises and their loudness are listed below:
Source of noise | Sound level in dB |
Breathing | 10 |
Rustle of leaves | 15 |
Whisper | 20 |
Speech | 60 |
Alarm clock | 70 |
Traffic | 60 to 90 |
Diesel or Electric Train | 80 |
Truck | 90 |
Food blender | 95 |
Pneumatic drill (at 3 metres) | 110 |
Propeller driven aircraft (at 30 metres) | 120 |
Jet aircraft (at 30 metres) | 140 |
Jet (taking off and flying overhead at 450 m) | 108 |
Rocket launching | 180 |
Aircraft noise
Perhaps 16 million people are exposed to aircraft noise globally. The Commission on aircraft noise (CAN) set up by the International Civil Aviation Organisation (ICAO) deals with aircraft noise. The source of sonic booms caused by supersonic aircraft, and aircraft noise in general is difficult to trace.
Music
The addition of amplifiers to music has led to high levels of noise. The smallest pop group with its 200-Watt amplifier can make music louder than a 100-piece symphony orchestra. Hearing damage from music depends not only on the volume but also on the number of concerts played or attended as seen in the table below.
The noise limit or Threshold Limit Value (TLV) is:
90 dB for eight hours
95 dB for four hours
100 dB for 15 minutes
Noise Limits
The maximum permissible noise levels in decibels dB can be seen below.
Road traffic near residential areas | 70 |
Noise on building sites | 70 |
When ear protection should be worn | 85 |
Factory work (8 hour, 5 days a week) | 90 |
Prolonged noise causing permanent damage | 100 |
Threshold of pain | 120 |
Absolute maximum with ears unprotected | 135 |
Absolute limit with ears protected | 150 |
Eardrum rupture | 180 |
Lung damage | 194 |