Independent tests have revealed that new diesel cars emit ‘huge’ amounts of ultra-fine particles that are not considered by the law despite being known to be dangerous to health.
Ultra-fine particles, which can be as small as 10 nanometres (nm), smaller than the size of a typical virus, are thought to be the most dangerous form of air pollution because they can penetrate deep into the body.
But current EU law on air pollution only considers particles that are larger than 23nm in diameter.
Transport & Environment (T&E) conducted lab tests on the Opel Astra and Nissan Qashqai, the second and fourth bestselling cars in their sectors.
The laboratory tests simulated real-world driving and measured a range of pollutants, including those which are currently unregulated.
The results showed that particle emissions increased from 11-184% when the smallest ultrafine particles were considered.
On some tests, the emissions from these tiny particles alone were enough to reach the legal limit.
According to T&E, this means that large amounts of particle pollution are completely neglected by the law, despite being potentially harmful to health.
T&E have said that these ultra-fine particles must be included in future testing.
The tests also found that regulated particle emissions from the diesel cars spiked to more than 1,000 times the normal level when the vehicles cleaned their filters, which can happen in urban areas and last for up to 15km, but because of a loophole in the law, the cars will still pass the official test.
Filter cleaning, to prevent the diesel particulate filter from clogging, can occur in all driving conditions, including in urban areas. In the tests, the number of particles continued to be higher during urban driving for 30 minutes after the cleaning had ended.
Anna Krajinska, emissions engineer at T&E said: ‘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.
‘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.
‘The endgame is a standard that demands zero emissions from cars on our roads.’
In related news, earlier this month, the UK government announced that they will ban the sale of new petrol, diesel and hybrid vehicles from 2035, bringing forward the original date by five years.
The 2035 date could even be moved forward further, subject to a consultation, to help the UK meet its 2050 net-zero climate target.
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