Dangerous decibel levels

Consultant ENT surgeon Dr. Seetha Arambepola defines noise pollution as the level at which noise exposure is harmful to humans and other animals, which is above the natural level of noise, set at 50 decibels.

“The most commonly experienced hearing ailments caused by noise pollution are hearing loss, tinnitus (which can be temporary or permanent) and vertigo,” she said.

Up to 80 decibels is acceptable in factories. If the level is between 80 and 85 decibels, the factory-owners and employers of a workplace have to advise their workers to be aware of continuous exposure to the sound.

If it is above 85 decibels, they have to recommend the use of sound protectors and if it is above 90 decibels, the employers are bound by law to provide these protectors to their employees.

The other factor is noise duration. The standard is set at eight hours for 90 decibels, but if this were to increase by five decibels the time is to be slashed by half, making it four hours, Dr. Arambepola explained.

“When sound waves travel to the inner ear through the ear drum and the middle ear, it sensitises the hair cells which are responsible for hearing. Loud noise damages this, sometimes causing sudden hearing loss. Sounds ranging from 100-120 decibels, usually at a party, wedding or the blasting of firecrackers causes an instant ear-block feeling called temporary tinnitus.