Which hugely popular small car is more polluting than a fully laden lorry?

One of the most popular small cars in Britain is as polluting as a fully laden lorry, test data has shown.

The VW Polo newest diesel edition emits as much as much toxic nitrogen dioxide (NO2) as an HGV with cargo.

“The worst-performing car [in the tests] was a VW Polo with a 1.4-litre turbodiesel engine with NO2 emissions 13 times higher than EU regulations allow,” James Tate of Leeds University’s Institute for Transport Studies, who analysed the test results, told the Sunday Times.

“Its emissions of 1.2 grams of NO2 per kilometre were the same as a fully laden diesel truck with a 13-litre engine that we also tested.”

Transport for London commissioned Millbrook, a vehicle testing firm in Bedfordshire, to drive the vehicles on a London route at night, during rush hour and at midday. The routes and vehicle acceleration and deceleration were recorded and replicated in test conditions.

13 cars and four lorries were tested.

“The key finding was that small diesel cars emitted far more pollution than larger cars and even lorries,” said Tate.

Other high polluters included a Vauxhall Astra, Ford Focus and BMW 318d.

“On average, the diesel cars tested emitted as much NO2 as 1,000 petrol-hybrid cars.

“These results also suggest that replacing diesel taxis with petrol-hybrids would be one of the quickest ways to improve city centre air quality,” he said.

Sadiq Khan, the mayor of London, said: “It beggars belief that 18 months after Dieselgate, motorists are still being sold vehicles that breach emission standards on the streets.”

As we reported last month, Mr Khan has announced the introduction of a £10 ‘T-Charge’ targeting 10,000 of the oldest, most polluting vehicles operating within the capital. The charge will be brought in on October 23 – the start of autumn half-term.

The T-Charge will walk alongside the Congestion Charge and will apply Monday to Friday from 7am to 6pm. The owners of diesel and petrol vehicles manufactured before 2005 that do not meet Euro 4 emissions standards for nitrogen oxide (NO2) and particulates will have to pay.

Mr Khan said: “It’s staggering that we live in a city where the air is so toxic that many of our children are growing up with lung problems. If we don’t make drastic changes now we won’t be protecting the health of our families in the future.”

He added that he considered the T-Charge a vital step in tackling the dirtiest diesels and said that he planned to introduce the world’s first Ultra Low Emission Zone as early as 2019.

“I will continue to do everything in my power to help protect the health of Londoners and clean our filthy air. But now is the time for Government to show real leadership and join me by introducing a diesel scrappage fund and bring in the new Clean Air Act we desperately need.”

The system will use a camera-based mechanism for enforcement and will monitor both diesel and petrol vehicles.

Leon Daniels, Transport for London’s (TfL) Managing Director of Surface Transport, said: “London’s air quality crisis is one of the biggest challenges we face and we are working alongside the Mayor to address it.

“The T-Charge is a crucial part of this work and will discourage drivers of the oldest, most polluting vehicles from driving in central London. To help drivers we have created an online compliance checker , which can be found on the TfL website, that enables people to easily establish whether they will be affected by the charge.”

The measure is however only expected to lead to a small reduction in toxic fumes.

Conservative London Assembly environment spokesman, Shaun Bailey, told the BBC (link is external) that TfL’s consultation showed the T-Charge would affect just 7 per cent of vehicles entering the Congestion Charge zone.

"Under assessment by his own people, the mayor's flagship air pollution policy is predicted to have only a 'negligible' impact on air quality, reducing poisonous NOx gasses by just 1-3%," Mr Bailey said.