(Xinhua)
Updated: 2007-08-17 23:22

Beijing began a four-day experiment early on Friday to test whether pulling 1.3 million cars off the capital's roads each day would be effective in reducing air pollution during the Olympics.

Drivers with even-numbered license plates, excluding taxis, buses and emergency vehicles, were told to stay off the roads on Friday or face fines.

Odd-numbered cars will be banned on Saturday and Monday, while vehicles with even-numbered registrations must also stay at home on Sunday.

"The experience we gain from this test will shed light on the adoption of measures to guarantee environmental quality at the Olympic Games next year," said Du Shaozhong, deputy director of the Municipal Environmental Protection Bureau.

The test period will also indicate if public transport can cope with the higher number of passengers and its effect on easing congestion, said an official with the Municipal Transport Commission.

Experts say pulling 1.3 million motor vehicles off the roads in Beijing each day can reduce exhaust emissions by 40 percent.

The air quality index in Beijing on Friday stood at 91 -- 51 to 100 represents "fairly good" air quality -- down from Thursday's figure of 115, classified as "slightly polluted".

However, an unhealthy haze still hung over the capital on Friday despite the measures to cut Beijing's vehicles by a third.

Guo Hu, head of the Beijing Meteorological Observatory, said the weather conditions in the city, which is surrounded by mountains on three sides, made it difficult for pollutants to dissipate and it would remain as it was on Friday for the next few days due to a lack of significant cold air currents and any rainfall.

Shi Hanmin, director of the Beijing Municipal Environmental Protection Bureau, said the test would be of great significance as the atmospheric pollution in Beijing was caused by a combination of sulfur dioxide, nitrogen dioxide, carbon monoxide and particulate matter, which largely resulted from exhaust emissions.

Tang Xiaoyan, a member of the Chinese Academy of Sciences and a member of the team researching air quality for the Olympics, said rainfall was the thing he feared most during the four-day test.

"To me, it doesn't matter much whether the air is polluted, or of good quality. If it rains other factors that cause pollution will be totally covered up," said Tang, also a professor with the Environmental Sciences and Engineering College of Peking University.

"Workers on the research team into Beijing's air quality will give priority to monitoring exhaust emissions during the four-day period and changes in the indicators will be studied closely," said Zhu Tong, a member of the research team.

Traffic flow appeared to be lighter on the first day of the test. There were fewer motor vehicles on the roads during the morning rush hour and a group of office workers who took shuttle buses to work said they arrived at their offices much earlier than usual.

Mr. Xu, who lives in the outlying Daxing District and owns an off-road Honda with an even-numbered registration, usually drives to his office in Xicheng District, downtown Beijing.

He had to leave his car home on Friday morning and take a shuttle bus arranged by his residential compound to Fuxingmen in downtown Beijing, about 15 minutes' walk from his office.

"It was a pleasant experience as I had chance to relax and take more exercise by not driving," said Xu.

Traffic in normally congested areas appeared to flow more freely. The second and third ring roads, where vehicles usually crawl along at less than 20 kilometers per hour in the rush hour, were unblocked.

A spokesman with Beijing Public Transport Holdings Ltd. said the usually clogged city roads were much clearer on Friday resulting in the efficiency of public buses rising by seven to 15 percent.

However, the increase in passenger numbers made the buses and subways more crowded. To ease the burden, 777 extra buses were put on the roads on Friday and intervals between subway trains were shortened.

Liu Xiaoming, deputy director of the Municipal Transportation Commission, said during the test period the number of buses would be increased and running times would be extended by an hour.

It is estimated that 8.4 million people will take public transport, including buses, the subway and taxis, over the four days compared with 6.4 million on average.

More delighted at the move may be the cab drivers. "We no longer have to find passengers. They come to us," said an unnamed driver. Beijing boasts nearly 80,000 taxis.

Around 1,600 taxis will be allocated to train stations and airports each day and more than 300 taxis will stay at more than ten venues of the "Good Luck Beijing" Olympic test event, according to the local transport commission.

Beijing also adopted the vehicle-control during the China-Africa Summit from November 1 to 5 2006, when more than 400,000 people signed a pledge not to drive during the summit. Levels of carbon monoxide in the air fell by 25 percent and nitro-oxygen by 20 percent.