Types of Community Noises
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Types of Community Noises

The following paragraphs discuss some of the sources of community noises, with particular reference to the Hong Kong situations.

Ambient Level

The day-time ambient sound pressure levels measured in rural and urban areas in Hong Kong are shown in Figure B4. These values are the minimum levels at the locations shown. The levels for rural areas, 44 to 55 dB(A), indicate the lowest level which exist in Hong Kong. Regrettably, the levels in housing estates are high. Depending on the location, the difference between rural and urban areas shown can be 10 to 20 dB(A).


Figure B4 Some Daytime Ambient Noise in HK


Construction Noise

Construction noise in Hong Kong comes from a number of sources, notably the pile driver, pneumatic drill, air compressor, concrete mixer and other diesel power construction machinery. Although the area affected by piling noise is far less than that of aircraft, the hazardous effect sometimes could be higher. This is because of the impulsive nature of the piling noise and the long duration of operation which may be more than eight hours a day. This means that the noise dose to people around a construction site may exceed the safety limit and hence may result in temporary and permanent shifting of thresholds of hearing.


Traffic Noise

Hong Kong has a very high vehicle density of about 200 vehicles per kilometers of road. Due to this high vehicle density, many main r ads in Hong Kong have daytime traffic volume of more than 3,000 vehicles per hour, and sometimes may reach 4,000 vehicles per hour in the rush hours. Figure B5 shows the time variation of the indoor sound pressure level due to the traffic at an adjacent road over a 24-hour period.

Figure B5 24-Hour Indoor Traffic Noise Survey

Aircraft Noise

In Hong Kong, the presence of the airport imposes very severe noise pollution on the highly populated areas under the flight path. Because of the large number of people severely affected by aircraft noise, and because of the tremendous costs involved to reduce the impact of this kind of noise, aircraft noise has received more attention than any other environmental noise.