Filter cleaning spikes particle emissions in new diesels, claims T&E


New diesel cars are exceeding EU limits for particle emissions, peaking at over 1,000 times their normal level, according to campaign group Transport and Environment (T&E).

T&E commissioned independent lab tests into the Nissan Qashqai and Opel Astra, the second and fourth bestsellers in their segments.

It found each model was between 32-115% over the legal limit of 600 billion particles per kilometre when their filters were cleaned.

Filter cleaning, to prevent the diesel particulate filter from clogging, can occur in all driving conditions, including in urban areas.

More than 45 million cars are said to carry these filters in Europe, reportedly causing a total of 1.3 billion filter cleanings a year.

The process can occur every two weeks and last for 15km (9.3 miles).

In the tests, the number of particles continued to be higher during urban driving for 30 minutes after the cleaning had ended.

Both models tested were under legal limits for NOx.

According to T&E, a loophole means that the legal limit does not apply when filter cleaning occurs in official testing, meaning that 60-99% of regulated particle emissions from the tested vehicles are ignored.

Total particulate emissions from the Nissan Qashqai and Opel Astra were further increased by 11-184% when unregulated ultrafine particles were measured in the lab.

T&E said lawmakers must accept that “diesels are still highly-polluting and should make emissions limits and testing more stringent”.

It also said the European Commission should require authorities to check cars on the road after they have been sold, as the US Environmental Protection Agency does.

The Nissan Qashqai and Opel Astra were 32-115% over the legal limit for particles when their filters were cleaned in the independent tests

Anna Krajinska, emissions engineer at T&E, said: “These tests show that new diesels are still not clean.

“In fact they are spewing out highly-dangerous levels of particles in our towns and highways everyday.

“Carmakers are being given an easy ride but people’s lungs are paying for it. Manufacturers should clean up their cars if they want to sell them.

“Regulated particles are only half the story. The smallest ultrafine particles are thought to pose a bigger threat yet they’re ignored by official tests.

“The next Euro pollution standard must close the loopholes and set limits for all pollutants.

“The endgame is a standard that demands zero emissions from cars on our roads.”

Reuters reported that Opel/Vauxhall said it couldn’t comment because it were not aware of the details of T&E’s report.

However, Nissan told the publication that “all Nissan vehicles and DPF (diesel particulate filter) devices fitted in our vehicles fully comply with applicable emissions legislation”.

Reuters also reported that the Japanese carmaker said it supported new, stricter emissions tests and had introduced new technology to meet them.