Emissions tests that are impossible for carmakers to cheat show that almost all diesel car models launched in Europe since the “dieselgate” scandal remain highly polluting.
The test uses a beam of light to analyse the exhaust plume of a car as it passes and automatic number plate recognition to link the measurement to a specific model. More than 370,000 such measurements taken in the UK, France and other countries have been compiled into new rating system called The Real Urban Emissions Initiative (True) and made available to the public on Wednesday.
Volkswagen was exposed as cheating emissions tests in September 2015. But, without breaking the letter of the law, almost all car manufacturers were producing diesels that emitted far more in real-world driving conditions than in official lab-based tests. This was done by optimising vehicles to pass standardised tests, but the beam test is conducted as cars pass and so cannot be manipulated.
The True analysis shows that new diesel models released in 2016 were still on average five over times above the EU’s official baseline limit of 0.08mg of nitrogen oxides (NOx) per kilometre. The 2017 models were a little cleaner, but still nearly four times over.
NOx pollution is at illegally high levels in numerous EU nations. It is estimated to cause 23,500 early deaths a year in the UK, where government plans to cut pollution have been repeatedly ruled so inadequate as to be illegal. Separate research published on Wednesday calculates that diesel cars and vans, which make up less than half the UK’s fleet, cause 88% of the health damage from light vehicles.
The beam tests are continuing and will be able to single out highly polluting models in future. “I see this remote sensing mostly as a screening tool, to see which vehicle models behave suspiciously,” said Peter Mock, at the International Council on Clean Transportation which produced the True rating in partnership with the FIA Foundation and other groups.
Those models highlighted as highly polluting could then be tested by putting a portable emissions measuring system (Pems) on a car, which is more accurate but also much more expensive. Diesel cars shown by the True data to emit far more NOx than the official baseline when on the road included two-litre Fiat Chrysler models – 18 times more – and 1.6-litre Renault Nissan models – 14 times more – though the cars passed legally required tests.
“If I was a customer, I would look at these figures at the moment and have to conclude I should not buy a diesel car,” Mock said, noting that the petrol versions are far cleaner. “Even Euro 6 [the most recent standard] diesel vehicles are not performing well at the moment so pretty much all of them should not have access to city centres.”