NOₓ is a generic term for the mono-nitrogen oxides NO and NO₂. They are produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures.
You may have read Volkswagen (VW) has been cheating in emission tests by making its cars appear far less polluting than they are. The US Environmental Protection Agency discovered that 482,000 VW diesel cars on American roads were emitting up to 40 times more toxic fumes than permitted – and VW has since admitted the cheat affects 11m cars worldwide. Apparently, the programming software in the car’s onboard computer could detect when the car was being tested for emissions and when this occurred the computer altered the way the engine processed the NOx so as to adhere to the safety standards.
It means far more harmful NOx emissions, including nitrogen dioxide, have been pumped into the air than was thought – on one analysis, between 250,000 to 1m extra tonnes every year. The hidden damage from these VW vehicles could equate to all of the UK’s NOx emissions from all power stations, vehicles, industry and agriculture.
Hopefully, the fines imposed on Volkswagen will destroy its credibility and make other manufacturers think twice before deciding to follow the makers of Das Auto.