The government has little idea of how much deadly nitrogen oxide (NOx) is being emitted by individual passenger cars because it has only one £100,000 machine able to test real-world emissions, it has emerged.
Until now, government vehicle inspectors have used laboratory tests that can be manipulated by car manufacturers with “cheat devices” to give false results, MPs on the environmental audit committee were told.
But following the VW scandal, when it emerged that the German company had installed devices to lower NOx emissions in its diesel engines, the government pledged to test other cars to see how widespread the practice might be and to ascertain the environmental impact.
According to Michael Hurwitz, director of the Energy, Technology and International Directorate at the Department for Transport, it will be several months before interim results can be made public. “The limiting factor is the availability of the £100,000 kits. We have one and and are looking to get another. But will not be possible to test thousands of vehicles in a short time,” he said.
Transport minister Robert Goodwill and environment minister Rory Stewart told the committee of MPs that they were not surprised at the divergence in CO2 levels between lab tests and real-world driving, which had been known about for several years and was not secret.
But with NOx emissions it was different. “We did not think that manufacturers were cheating. We were aware of discrepancies which we attributed to manufacturers designing engines for the test. We thought that the tests were bad, not that people were cheating,” said Stewart.
The ministers said they had been impressed that heavy goods vehicles (HGV) with new Euro VI engines emitted much less NOx gas. “Possibly we were naive to think that passenger cars would perform as well,” said Goodwill.
But they insisted they wanted much better testing of passenger cars as soon as possible. “The euro VI standard is being broken by factor of five. This is unacceptable. We are working with the German government to test cars on the road. We are working to come up with better tests which will be more accurate,” said Stewart.
He played down freedom of information reports showing that the industry lobby had easy access to ministers, with more than 200 meetings recorded between them in the last parliament – but only two meetings with clean air groups.
Instead, he said that the VW scandal had changed the position of other countries which now wanted stricter testing. “In May the UK was the only government wanting real-world tests. Now almost all support us.”
Goodwill defended diesel in the face of mounting medical evidence that its fumes were dangerous to health, and figures which showed that numbers of diesel vehicles had increased from 1.4m on the road in 1994 and 10.7m now.
“In terms of taxes, diesel has not been discriminated for or against. Diesel has played a major role in reducing transport emissions. We will better positioned to [know its health impact] when we have tested vehicles across the fleet to see the discrepancies between laboratory tests and real-world emissions,” he said.