VW scandal caused nearly 1m tonnes of extra pollution, analysis shows

Volkswagen’s rigging of emissions tests for 11m cars means they may be responsible for nearly 1m tonnes of air pollution every year, roughly the same as the UK’s combined emissions for all power stations, vehicles, industry and agriculture, a Guardian analysis suggests. The potential scale of the scandal puts further pressure on Volkswagen’s board and its chief executive, Martin Winterkorn. The company’s executive committee plans to meet on Wednesday to discuss the affair and to agree the agenda of a full board meeting scheduled for Friday, amid reports that Winterkorn could be replaced.

The carmaker has recalled 482,000 VW and Audi brand cars in the US after the Environmental Protection Agency (EPA) found models with Type EA 189 engines had been fitted with a device designed to reduce emissions of nitrous oxides (NOx) under testing conditions.

A Guardian analysis found those US vehicles would have spewed between 10,392 and 41,571 tonnes of toxic gas into the air each year, if they had covered the average annual US mileage. If they had complied with EPA standards, they would have emitted just 1,039 tonnes of NOx each year in total.

The company admitted the device may have been fitted to 11m of its vehiclesworldwide. If that proves correct, VW’s defective vehicles could be responsible for between 237,161 and 948,691 tonnes of NOx emissions each year, 10 to 40 times the pollution standard for new models in the US. Western Europe’s biggest power station, Drax in the UK, emits 39,000 tonnes of NOx each year.

Germany’s Tagesspiegel newspaper said on Tuesday that VW’s board would replace Winterkorn, who has led the company since early 2007, with Matthias Mueller, who runs the company’s Porsche sports car division. Volkswagen rejected Tagesspiegel’s report and Winterkorn continued to ask for the public’s trust on Tuesday, saying the scandal was caused by “the bad mistakes of a few”. But Wednesday’s meeting will prove crucial to how VW responds.

The company’s shares fell 10% as the German stock market opened on Wednesday although recouped some early losses. A thrid – some €25bn – of the company’s stock market value had already been lost since Friday when the emissions scandal first emerged.

New York and other state attorney generals are forming a group to investigate the scandal, New York attorney general Eric Schneiderman said, adding to a series of investigations in the US, Europe and Asia that threaten to sap Volkswagen’s resources and impose large penalties.

In the US, just 3% of passenger cars are diesel compared with almost half in the EU. Prof Martin Williams of King’s College London said the US’s low percentage of diesel cars meant higher diesel emissions in some cars would have a “limited effect” on air quality there.

“[In the US it would be] nowhere near the effect it would have in this country and in the rest of Europe for that matter,” he said. In the UK, Williams added, emissions from diesel cars cause roughly 5,800 premature deaths each year. “If you were to make the cars emit at the legal limit you could reduce those deaths by at least a factor of two and maybe more. Maybe a factor of five.”

The Clean Air in London campaign called for a royal commission to investigate carmakers’ activities in the UK. “Diesel is without doubt the biggest public health catastrophe in UK history. Even the black plague didn’t affect everyone in the population,” said its founder, Simon Birkett.

Not all NOx emissions – which include nitrogen dioxide (NO2) and nitrogen oxide (NO) – are dangerous. But an increasing proportion of the toxic NO₂ gas has been detected in EU diesel emissions. A study in the British Medical Journal in May found that short-term exposure to NO₂ increased the number of premature deaths from heart and lung disease by 0.88% and 1.09%.

For years, UK air pollution measurements have failed to show improvements in air quality, even as standards have tightened.

“Since 2003 scientists have been saying things are not right. It’s not just the VW story, this is part of something much bigger,” said Dr Gary Fuller, also of King’s College. “It has a serious public health impact.”

Last week, a report from NGO Transport & Environment found that Europe’s testing regime was allowing nine out of every 10 new diesel vehicles to breach EU limits. Testing regimes in the EU are known to fail to pick up “real world” emissions because cars are not driven in the same way in the laboratory as on the road. Some studies suggest the discrepancy may be up to seven times the legal limit.

Williams said being able to mask their NOx emissions would also enable carmakers to pass carbon emissions tests more easily as there was a trade-off between NOx and CO2 in diesel engines.

Catherine Bearder MEP, a lead negotiator on the EU’s new air quality laws, said: “Manufacturers in the US have been caught out, but we know that pollution limits are also being breached in Europe … Unless we take action, thousands of lives will continue to be tragically cut short by air pollution.