"but as we've learned the NOx regulations were too strict and not achievable."
Not to minimise this but Eur 6 does seem to be achievable BUT the standard is for a certain mix of simulated driving. As I've mentioned before this will never represent all the possible conditions of actual use.
In any case the actual risk to health is a function of the concentration.time product which can't be garnered from tailpipe emissions directly as it depends on so many factors. ( traffic density & speed , wind & rain, mix of HGVs vs vans vs cars, background levels of NOx from other sources [heating, industry] )
Biting the hand that feeds IT
