Enough hysteria, already. Sure, it’s shocking, knowing bosses at Volkswagen used naked, unprincipled, indefensible skulduggery to get their cars past American emissions standards that honest rivals found almost impossible to achieve.

But now, downstream of the revelations, I reckon it’s time for a bit of calm. The key controversy is over emissions of NOx from car exhausts, about 40% of which emanates from all transport sources, and half of that from cars. The crooked VWs are thus responsible for a slice of 20%, so even if they could be rendered legal overnight, we’d still have a problem.

For decades we’ve been directed by academics and government agencies to care most about reducing CO2 on the grounds that it’s a greenhouse gas that contributes to global warming. Diesels emit less CO2 than petrol engines (good) but much more NOx (bad), and the latter is now accepted as a serious health hazard. Things must change.

But instead of making ourselves feel better by spitefully bankrupting a mostly excellent and capable company (at risk of 650,000 jobs), I believe we should spare no effort to find the miscreants, throw the book at them very hard and then move on.

The greatest service the industry and the authorities could do us consumers is to tell us the simple truth about atmospheric NOx - to guide our future car decisions. At the same time, they should also ensure that VW remains stable enough to devise remedies for its misdemeanours at top speed. No other company or agency would have as much expertise or motivation. 

Read more on the Volkswagen emissions scandal:

How the Volkswagen story unfolded

How VW's 'defeat device' works

Top VW bosses to leave

European cars are affected, says German minister

PSA Peugeot Citroën leads calls for tougher emissions test procedures

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