Nitrogen oxides in car exhaust kill tens of thousands in UK

We have long known that NOx, and in particular NO2 – which form part of the discharge from car exhausts – are indirectly harmful.

To put that in context, PM2.5 prematurely killed an estimated 430,000 people in the 28 EU countries in 2012, according to the European Environment Agency.

When diesel is burned in an engine instead of petrol, more NOx is produced overall, and 70 per cent of the NOx produced is NO2, compared with only 10 to 15 per cent when petrol is burned.