We thank Mr Shawn Loh for his letter (More fairness needed in scheme to deregister older bikes; April 11).
In estimating our motorcycle emissions, the National Environment Agency (NEA) considered the population of motorcycles, their respective emission standards, mileage travelled, engine size and other factors.
From these estimates, motorcycles were found to emit 53 per cent of total vehicular carbon monoxide emissions although they account for just 15 per cent of Singapore's vehicle population.
Using a similar approach, we found that motorcycles registered before July 1, 2003, contribute to 40 per cent of carbon monoxide emissions from motorcycles while making up only 21 per cent of Singapore's motorcycle population.
Singapore adopted Euro I standards for new motorcycles on July 1, 2003.
Motorcycles registered before that date emit up to about 10 times more carbon monoxide and 30 times more hydrocarbons than new Euro IV-compliant motorcycles.
These older motorcycles also emit 12 times more carbon monoxide and 50 times more hydrocarbons than a Euro VI-compliant car.
The NEA has introduced various initiatives to manage vehicular emissions, such as Euro VI emission standards, the Vehicular Emissions Scheme, the Early Turnover Scheme for commercial vehicles, and the tightening of in-use emission standards for vehicles.
A statutory lifespan for goods vehicles and buses, tuition cars and taxis - 20 years, 10 years and eight years respectively - has also been implemented.
We currently have no plans to implement similar measures for cars that are 15 years or older, as they account for only about 1 per cent of the car population.
Owners of motorcycles registered before July 1, 2003, will be able to use their motorcycles for another 10 years, before they are phased out on June 30, 2028.
By 2028, these motorcycles would have been on the road for at least 25 years.
We have received feedback from some owners of motorcycles which will not qualify for the Classic Vehicle Scheme as they will not be 35 years old by June 30, 2028, and will continue to address their inquiries.
Phasing out older, more pollutive motorcycles will reduce carbon monoxide, hydrocarbons and ground-level ozone.
The NEA will also continue its enforcement against smoky vehicles at our land entry checkpoints and roads, as well as look at measures to further reduce pollution from foreign motorcycles.
Cheang Kok Chung
Director, Environmental Protection Policy & International Relations Division
Deputy Director-General, Environmental Protection
National Environment Agency