Plan to slash emissions by updating old buses

The government is planning to fit 1,400 older buses with devices that will cut their nitrogen oxide emissions by over 60 per cent.

The Environmental Protection Department is seeking HK$400 million for the project after seeing the results of a 17-month trial which showed the equipment can reduce emissions by between 63 and 81 per cent.

Six buses that were built to Euro II and Euro III specifications of the 1990s were fitted in 2011 with selective catalytic reduction devices, or SCRs. Their emissions were reduced to levels comparable with Euro IV buses that used technology a decade more modern, the department said.

There were also no unacceptable emissions of other pollutants, such as carbon monoxide and total hydrocarbons.

The department said the trial showed that the retrofit was technically feasible for the Euro II and Euro III Dennis Trident and Euro II Volvo Olympian models - although there had been some maintenance and operational problems which were fixed.

Four other Euro II and Euro III models could also be retrofitted, it added.