Thousands driving diesel cars illegally

Tests fail to spot vehicles on road without filters

‘Making it even more toxic’

THOUSANDS of motorists are illegally driving modified diesel cars without pollution filters, an investigation has found.

Broken filters can cost more than £1,000 to replace so drivers are removing them for a fraction of the price, with 1,800 cars caught without the filter since 2014, the Driver and Vehicle Standards Agency found.

Many more vehicle owners could be getting away with it because emissions tests do not always detect the alterations, experts warned.

All new diesel cars produced after 2009 have diesel particulate filters installed.

However, processing large amounts of particulate matter means they become clogged and break down easily.

It is not illegal to remove the filter and the procedure involved costs a few hundred pounds – but driving a modified vehicle is against the law.

For those caught, it can be punished with a £1,000 fine, for a car, and £2,500 for a van.

The pollution caused by the particulate matter in the fumes can lead to lung cancer, heart attacks and strokes, as well as causing damage to unborn children in the womb.

A car which has had its diesel filter removed has a particulate count 20 times higher than one with it, King’s College London professor of environmental health Frank Kelly said. At least 38,000 premature deaths worldwide each year are linked to the noxious fumes from diesel engines, according to World Health Organisation figures.

The filters work by trapping soot from the diesel’s exhaust then burning it into harmless ash using heat from the engine.

This process can only take place at very high temperatures – such as those achieved during prolonged motorway driving.

This can mean that cars used for predominantly urban journeys are more likely to clog with soot and break.

Garages can cut a small window into the outside of the filter, remove it then weld the window shut to give the visual impression it is still intact. An MOT test only requires a visual examination of the outside of the filter and current emissions tests are not reliable enough to detect whether it is there. Tests able to detect a modified filter will not be rolled out until May next year.

The health risks posed by unfiltered diesel engines are not taken seriously enough, according to Jonathan Grigg, professor of paediatric respiratory and environmental medicine at Queen Mary University in London.

‘By removing the diesel particulate filter you are taking a toxic vehicle and making it even more toxic,’ he told the Daily Telegraph.

‘When you breathe in diesel emissions a lot of what goes into your lungs is soot.’

‘Some of that soot will continue to stay in your lungs even after you breathe out multiple times.

‘Living in an urban area you only take in a small amount of these particles every day, but what we are learning is that over the course of a lifetime that these effects accumulate.’