Sixty-eight decibels is equal to the sound of normal speech, experts said.

Beijing has long been beset by traffic noise pollution, which has lingered at an average level of between 71 and 72 decibels for many years, according to sources with the Beijing Environmental Protection Bureau.

The capital city ranks the third serious noise polluted city around the country, and traffic noise surpasses the maximum of 70 decibels that national regulations permit in urban areas.

A decibel is the unit used to measure the intensity of sound. People generally feel at ease with a noise level of 40 to 60 decibels.

Any sound above 85 decibels can cause hearing loss. Hearing loss is related both to the power of a sound as well as the length of exposure.

Eight hours of 90 decibels of sound can cause damage to your ears; any exposure to 140 decibels of sound can cause immediate damage and pain, according to experts.

It is estimated that around 1 million people in the city live along the main arteries of traffic where sound intensity averages above 85 decibels.

This implies that at least 16 percent of Beijingers in urban areas are suffering from severe noise pollution from traffic every day.

Experts point out that the speed, size and tonnage of a vehicle, road conditions and the distance between streets and construction sites have a direct bearing on traffic noise.

Beijing plans to earmark 270 million yuan (US$32.6 million) for noise-reducing protection of residents living in buildings near major roads, using sound insulating windows and acoustic celotex boards as the main methods.

For instance, along the newly built urban railway from Huoying in the northern suburbs to Xizhimen in central Beijing, special acoustic celotex boards were set up at some sections to reduce the noise caused by trains.

Meanwhile, large trucks and agricultural vehicles that enter the city at night will be restricted to certain routes and speeds, according to the bureau.

Another effective method to curb traffic noise is to plant trees along roads, and the city will invest 120 million yuan (US$15 million) by 2005 to build at least 100 kilometers of green screens that absorb sound on busy streets, which will reduce noise intensity by four to six decibels.

Another investment of 120 million yuan (US$15 million) will be put into the improvement of road conditions. A city wide noise monitoring system and traffic noise control labs will also be established, the bureau said.

(China Daily November 26, 2002)