The Environmental Protection Department yesterday unveiled a plan to use roadside remote sensing equipment to monitor whether liquefied petroleum gas (LPG) taxi cabs meet emissions control standard.

A public consultation session will be launched in January to invite comments on its plan, said department assistant director Tse Chi-wan yesterday.

LPG cabs are more environment friendly than diesel-powered ones provided that they are properly maintained.

A department spokesman cited a study by the Hong Kong Polytechnic University to suggest that a diesel-powered taxi emit 0.18 gram of nitrogen monoxide for each 50-kilometer ride, as compared to 0.07 gram by an LPG cab.

The study was aimed at examining the impact of maintenance on the functioning of LPG cabs.

The spokesman said that the department had requested the LPG cab manufacturers to give statistical evidence that their products are more environment friendly before they are introduced to Hong Kong. He said a diesel-powered taxi cab emits between 18 and 100 times nitrogen oxides more than an LPG cab.

But Tse conceded that emission monitoring needs to be stepped up to see whether LPG cabs are properly maintained.

The department will do so by employing roadside remote sensing equipment to keep tabs on vehicle emissions in January.

"LPG cabs do not produce black smoke, and the pollutants they emit are not visible. It is therefore necessary to use the equipment, which can tell us whether the taxis have undergone proper maintenance. Drivers will be requested to have their cabs repaired based on the results given by the equipment. We are in the final stage of preparation for the public consultation session," Tse said.

PolyU mechanical engineering associate professor Cheung Chun-shun said repairing plays a key part in maintaining the environmental value of LPG taxies.

"The cabs environment function will be impaired by the lack of maintenance," he said.

Conservancy Association chairman Betty Ho welcomed the use of emission sensing equipment, saying it would assist air pollution control.

(HK Edition 11/06/2007 page6)