YOU MAY HAVE noticed an angry letter to the editor yesterday from Director of Environmental Protection Robert Law ('Suggestions of sinister dealings are completely groundless'), saying I had it all wrong in doubts I earlier cast on how a tender for particulate matter traps on light diesel engines was conducted.
Right, here we go. In February 1998, the Environmental Protection Department (EPD) received a diesel pollution study specially prepared for it by a respected expert, Michael P. Walsh.
The study dealt with all forms of diesel pollution, different exhaust-control devices, various manufacturers of these devices and the record of their use abroad. With reference to light diesel vehicles, it said tests showed that traps could reduce regulated particulate emissions by just over 80 per cent for a typical IDI (InDirect Injected) diesel and by up to an order of magnitude for an older IDI diesel.
Next we turn to a Legislative Council briefing paper in May 2000 (CB(2)1909/99-000(01)) from the Environment and Food Bureau, which says that the Polytechnic University has developed a low-cost particulate trap and, following trials in conjunction with the EPD, proposes retrofitting them in Hong Kong.
This paper says that 'on a comprehensive emission testing conducted by the Tianjin University, the trap can reduce up to 30 per cent of the particulate emissions . . .' Note the 'up to' 30 per cent, not 'just over' 80 per cent or an order of magnitude, and that no precise reference is given here to the tests used. It is given elsewhere in a PolyU report dated July 2000, which cites a precise 30 per cent (not 'up to') and cites ECE-R49.
However, a check on the Internet with a site called dieselnet.com defines ECE R-49 as a steady state cycle test for heavy-duty truck engines, not light duty, and also says it was used before 2000. We are now already well into 2000.
The Legco paper also says that a technical committee will be formed to identify traps which could perform 'at least as well' as the PolyU's but notes 'it would not be efficient use of time and resources' to arrange a trial for each of them and the proponents themselves will have to 'demonstrate the efficacy of their products'. The schedule in this paper calls for tendering in June, evaluation in October and retrofitting to start in December 2000.