2 factories The noise caused by the operation of various sizes, which leads to different sound levels ranging from 60 dB to 120 dB, depending on the size of unit. The plant material or ceiling. The environment of the factory.
3. From household noise from engine. Appliances such as lawn mowers, vacuum cleaners, floor polishers, radio and television, the noise level was about 60 -70 dB.
4 noise caused by other reasons, such as advertising, thunder, lightning, and other sounds spat.
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