The Government proposes to tighten the specifications for unleaded petrol to the Euro IV level with effect from January 1 to help improve roadside air quality as motor vehicles are the major source of roadside pollution in Hong Kong.

The Environment, Transport & Works Bureau said there is plan to start making Euro IV emission requirements mandatory for newly registered vehicles from 2006 in step with the European Union.

Euro IV unleaded petrol specifications will lower the sulphur limit by 67% and the aromatic hydrocarbons limit by 17% as compared with the current Euro III unleaded petrol.

The bureau said with Euro IV unleaded petrol, Euro IV petrol vehicles emit about 50% less nitrogen oxides, carbon monoxide and hydrocarbons than with Euro III unleaded petrol.

It added the European Union will also tighten its unleaded petrol specifications to the Euro IV level from January 1, to prepare for subsequent implementation of the Euro IV vehicle emission standards.