Shanghai has developed cost-efficient technology to cope with air pollution in tunnels, and it is expected to be in use for the World Expo in 2010.

Engineers and scientists have been researching and testing the technology since October 2007, and when it is completed by December next year the local government will have spent 3.05 million yuan (US$447,102) on the project.

City officials expect to have the new equipment installed on some vehicle tunnels before World Expo to help ease the levels of pollution.

The city's first tunnel, the Dapu Road Tunnel, under the Huangpu River, was built in 1970. Shanghai now has six vehicle tunnels in service under the Huangpu River and is on track for another six.

Some of the tunnels, like the Yan'an Road, the Dapu Road and the Outer Ring Road tunnels, have been operating far beyond their designed traffic capacity and now suffer not only from traffic congestion but serious air pollution.

The increased traffic has left the ventilation systems unable to cope with the level of contaminants inside the tunnels. As well, untreated air being pumped from the tunnels adds to pollution outside, said officials with the Shanghai Engineering Administrative Bureau, the project leader.

Project engineers have begun testing the new air-purifying technology at some of the city's tunnels.

The engineers said the new technology will substantially reduce pollutants like carbon monoxide and nitrogen oxide by at least 65 percent while at the same time lowering the level of particulate in the tunnel air by 80 percent. When the new air-purifying technology is installed, it will also lower the pollution levels on the air that is extracted.

The project also involves the development of photo-catalyst technology which uses clean energy from the sun or artificial light to destroy air pollutants.

A 120-meter section in the Fuxing Road Tunnel was renovated with photo-catalyst technology early last year. Engineers said this had reduced 45 percent of the harmful particulates in the tunnel air.

The project is one of the city's major scientific efforts for 2010.

(Shanghai Daily September 27, 2008)