No mention by any of these eminent specialists that DPF'S/Catalytic converters do not work in an urban drive cycle. London has already been singled out as the worst city to drive in Europe to drive in. Mainly because of the reckless traffic management systems introduced by TFL.
It is a known scientific fact that diesel particulate matter is factor towards deaths from pollution.
Another factor being: DPF's and Catalytic Converter failure due to poor traffic management pollutes the air with other toxins such as ammonia - other more harmful toxic emissions the unstable chemical reactions produced that are NOT being checked or measured such as Nerve gas, Cyanide gas and Hydrogen Sulphur gas (smells like rotten eggs), in ADDITION to the common toxic emissions, Carbon Monoxide (CO), Hydrocarbons (HC) and Nitrogen Oxide (NOx).
Lastly, there has been no scientific study to determine the effects of petrol engines in an urban environment such as London.
Why are Taxis not produced with Petrol LPG engines?
This is all about money, and nothing to do with tackling the harmful effects of emissions. Basically, these people are talking absolute unfounded rubbish.