HL Deb 24 October 2000 vol 618 cc138-9

2.52 p.m.

Lord Campbell of Croy asked Her Majesty's Government:

Whether they are encouraging the experiment being conducted with paving stones containing titanium oxide in order to test their effectiveness in extracting polluting substances from the atmosphere.

Lord Whitty

My Lords, the Government are not directly involved with this experiment. I understand that Westminster City Council is considering a possible trial of some paving stones containing titanium dioxide but that the idea is at an early stage. We shall be interested to learn of any results in due course.

Lord Campbell of Croy

My Lords, I am grateful to the Minister for his reply. Provided the stones meet the essential requirements for sound and solid paving, do the Government foresee a useful possible role for them in urban areas in removing pollution caused by motor traffic? I believe that everybody would support that, and that it would be welcomed.

Lord Whitty

My Lords, it is too early to comment positively on that. I understand that Westminster City Council has had discussions with Mitsubishi Materials, the manufacturers of the paving stones, which have been trialed in Osaka, Japan. However, we do not have the full outcome of those trials. It will be a matter for Westminster City Council, in discussions with the manufacturers, to decide whether the paving stones would be appropriate for this area. Should those answers be positive, clearly the Government would be interested. However, it is far too early to comment.

Baroness Gardner of Parkes

My Lords, can the Minister confirm that the basis on which the stones are supposed to work is by converting nitrous oxide into nitrogen and oxygen and so purify the air? Is he also aware that sunlight is a necessary factor in that process? Does he think that our climate in this country might occasionally make it difficult to quantify the result?

Lord Whitty

My Lords, there are such variables. The noble Baroness is correct in describing the chemical process, which requires ultra violet rays. However, I believe that the City of Westminster receives sufficient days of sunshine for this process to be effective if everything else applies. There is potential scope, but, as I have said, many uncertainties.

Baroness Sharpies

My Lords, can the Minister tell the House whether the stone is a composite or natural stone, such as York stone?

Lord Whitty

My Lords, it is probably natural stone. The only extant example is in Japan, so I doubt whether it corresponds precisely to York stone. It is heavily impregnated with titanium dioxide, which changes the composition.

Lord Campbell of Croy

My Lords, if the experiments were to indicate wider effectiveness, might not that material also be used near other sources of air pollution, for example, downwind of refineries and sewage works?

Lord Whitty

My Lords, the emissions from such installations are slightly different to those from road traffic. I agree that we are primarily dealing with nitrogen dioxide. Once again, there are many uncertainties in this area. It is too early for me to pronounce on the noble Lord's Question.

Earl Ferrers

My Lords, if the Government do not like chemicals such as fertilisers and pesticides, what is the virtue of putting down chemicals on the streets to remove chemicals from the air?

Lord Whitty

My Lords, the Government are not opposed to appropriate use of pesticides. However, we are opposed to inappropriate use. If the process proves to be appropriate, we shall consider it for wider use. Perhaps I may repeat that this is far too early a stage to comment.