Cleaner diesels

A really unpleasant aspect of urban cycling is the lungful of black smoke you get when following many lorries and buses. ‘Particulates’ – soot – from diesel engines are a big health hazard, too. Catalytic converters on cars are gradually reducing some of the invisible pollutants in the atmosphere. However, because catalysts aren’t effective until the engine has warmed up, pollution will increase again if traffic continues to grow, especially if shorter journeys are not reduced. But legislation on diesel smoke has been lax in comparison.

Lorry exhaust may become cleaner by 2005
Image as described adjacent

Now it looks as if some headway is being made. Before Christmas, EU ministers agreed a set of new controls for large vehicles. The controls are intended to cut particulates by 30% by next year, and by 90% over the next six years. Given that this will partly be done by ‘soot traps’ – physical traps that stop even the smallest particles escaping – it is hard to see why it has taken so long.

Emissions of nitrogen oxides from large vehicles will also be cut by 30% next year; but a further 60% reduction will take until 2008 – far too long. A third measure means manufacturers will have to show how much carbon dioxide their new cars produce.

One feature of diesel engines is that they produce dramatically more pollution if they are not maintained. Because heavy lorries work on a shoestring budget, we have to be sceptical about the effectiveness of the particulate directive, but at least soot traps can be retro-fitted to existing vehicles. Some of the gain will be achieved by improved fuel manufacturing.

Finally, one local consequence of the take-over of Cambus by Stagecoach is that for the first time in years some real investment is being made in new buses in the City. This means some of the oldest and filthiest buses are being replaced with much cleaner models. I am aware of how few buses I see producing clouds of black smoke, compared to only three or four years ago.

David Earl