Advisory Council on the Environment

Retrofitting Pre-Euro Diesel Vehicles with Particulate Traps or Catalystsc Air Pollution Control Ordinance (Cap. 311)

(ACE Paper 1/2002)
For advice


This paper seeks Members' advice on the following proposals -

  1. to mandate the installation of particulate traps or catalysts for pre-Euro diesel light vehicles; and
  2. to retrofit pre-Euro diesel heavy vehicles with catalysts.


2. Diesel vehicles are a major source of roadside air pollution. One of our measures to reduce their emissions is to retrofit the older and more polluting diesel vehicles with emission reduction installations. In May 2000, we informed Members through ACE Paper 20/2000 of our plan to retrofit pre-Euro diesel light vehicles with particulate traps or catalysts. Subsequently between September 2000 and October 2001, we implemented a programme to provide financial assistance to owners of pre-Euro diesel light vehicles four tonnes or below for retrofitting their vehicles with particulate traps or catalysts. About 80% of the pre-Euro diesel light vehicles (or about 24 000 in number) participated in the programme.

3. To ensure that the retrofitted vehicles would continue to use the particulate traps or catalysts properly and to require those that did not participate in the Government programme to be retrofitted with suitable particulate traps or catalysts, we propose to introduce a new regulation under the Air Pollution Control Ordinance (APCO) (Cap. 311) to mandate the installations for this category of diesel light vehicles. When the proposed regulation is brought into operation, owners of pre-Euro diesel light vehicles will be liable to cancellation or non-renewal of their vehicle licences if their vehicles are found not properly installed with a type-approved particulate trap or catalyst.

4. The enforceable arrangements will be as follows -

  1. At present, all commercial vehicles irrespective of age and all diesel private cars over six years old have to pass an annual roadworthiness inspection before the Transport Department will renew their licences. When the proposed regulation becomes effective, pre-Euro diesel light vehicles not properly installed with a type-approved particulate trap or catalyst will not pass the inspection and their licences will not be renewed.
  2. The Environmental Protection Department may refer any pre-Euro diesel light vehicles found not properly installed with a type-approved particulate trap or catalyst to the Commissioner for Transport with a recommendation that their licences be cancelled, as for the present practice regarding vehicles that have failed the Department's smoke tests.

5. We plan to table the proposed regulation, which is a subsidiary legislation, at the Legislative Council in early 2002. In order to allow time for vehicles that have not yet been retrofitted to get the installations, we plan to bring the proposed regulation into operation around the middle of this year.

6. There are a small number of pre-Euro diesel light vehicles which are special purpose vehicles mainly used as equipment, or for which there are no suitable particulate traps or catalysts. The proposed regulation will grant the Director of Environmental Protection discretionary power to exempt such vehicles from the mandatory requirement where appropriate.

7. For the list of type-approved particulate traps and catalysts, the Environmental Protection Department will set up an expert panel very shortly to draw up the list and update it in future.


8. In ACE Paper 20/2000, we informed Members that we had launched a trial of retrofitting pre-Euro diesel heavy vehicles with catalysts; that a Monitoring Committee comprising representatives of the transport trades (including the Motor Traders Association), academics and other relevant government departments had been set up to oversee the trial; and that, subject to satisfactory trial results, we planned to provide financial assistance to owners of pre-Euro heavy vehicles for retrofitting their vehicles with suitable catalysts. 59 pre-Euro diesel heavy vehicles including government and private vehicles took part in the trial. The performance of different catalysts was checked regularly. In addition, two questionnaire surveys were conducted to gauge the views of the drivers of the vehicles participating in the trial such as their views on the impact of the catalysts on smoke emission, fuel consumption and lubrication oil consumption of the vehicles.

9. The trial has found that the catalysts are effective in reducing the emissions of particulates, carbon monoxide, hydrocarbons and smoke of pre-Euro diesel heavy vehicles. The key findings of the trial are as follows -

  1. the catalysts can effectively reduce the emission of particulates, a major pollutant in our air, by more than 35%;
  2. the catalysts work best when the vehicles are going uphill, i.e. when they emit the largest amount of exhaust. When the vehicle is heavily loaded, the catalyst can reduce smoke by about 40%;
  3. the effectiveness of the catalysts in reducing carbon monoxide and hydrocarbons is comparable to and sometimes better than their effectiveness in reducing particulates and smoke;
  4. the catalysts have negligible effects on the performance of vehicle engines such as engine power and fuel and lubrication oil consumption; and
  5. suitable catalysts are available in the market for use on different vehicles including those that need to travel into the Mainland and use motor diesel that has a higher sulphur content than motor diesel in Hong Kong.

10. While the catalysts are effective in reducing the particulate, carbon monoxide and hydrocarbon emissions of all pre-Euro diesel heavy vehicles, the trial has revealed that vehicles which need to keep their engines running while stationary to support their on-board ancillary equipment (such as crane lorries, concrete mixer trucks, and signal light vehicles) will emit white smoke occasionally after a catalyst has been installed on them. Different catalysts have been tried with the attempt to resolve the problem but so far no suitable catalyst that will not cause this problem of white smoke has been found.

11. At present, there are about 45 000 pre-Euro diesel heavy vehicles excluding franchised buses. Franchised bus companies have already taken the initiative to retrofit their pre-Euro buses with catalysts. So far, about 90% of such buses have been retrofitted. The remaining ones will be replaced with Euro III buses by end 2002. Of the 45 000 pre-Euro diesel heavy vehicles, about 4 000 belong to the category of long-idling vehicles. There is considerable support in the Monitoring Committee, including those from the representatives of the transport trades on the Committee, for retrofitting all pre-Euro diesel heavy vehicles with catalysts. The Monitoring Committee suggests that a programme to retrofit all pre-Euro diesel heavy vehicles except for the category of long-idling vehicles should be implemented in the first instance and that the search for suitable catalysts for the long-idling vehicles or a way to resolve the problem of white smoke should continue separately. We support the recommendations.

12. To take forward the retrofit programme, the Environmental Protection Department has engaged an independent expert panel comprising one local and four international experts to draw up a technical specification laying down the functional requirements of the installations. In drawing up the specification, the expert panel has consulted the Monitoring Committee and major catalyst manufacturers worldwide. Since this will be a functional specification, we will consider products other than in the form of a catalyst provided that they meet the specified functional requirements.

13. We intend to seek approval from the Legislative Council Finance Committee in the coming months for funding to retrofit about 41 000 pre-Euro diesel heavy vehicles (less the 4 000 long-idling vehicles which will be left out from the programme for the time being pending identification of an installation or method to resolve the white smoke problem) with catalysts or other installations. The total cost of the programme is estimated to be about $600 million. Subject to Finance Committee's approval, we plan to invite tenders in the coming months, award the contracts by around mid-2002, start the retrofit programme shortly after summer this year and complete it by mid-2004. After the retrofit programme has been completed, our plan is to mandate the installations for pre-Euro diesel heavy vehicles.


14. Members are requested to advise on the proposals set out in para. 1 above.

Environment and Food Bureau
January 2002




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