A new report has revealed the six-cylinder diesel Ingenium powering many Discovery 5s could be among the cleanest engines on sale today. The independent study shows NOx exhaust emissions from Land Rover’s latest Discovery to be 20 times lower than those of a 2017 Renault Clio.
These are the first figures published by the AIR Index, a new ‘independent global alliance’ that aims to improve transparency in the way vehicle emissions are tested. Exhaust gases are analysed to European standards, using vehicles that are sourced and tested independently, without the knowledge of manufacturers.
Unlike the closed-doors lab testing that has been blamed for enabling Volkswagen’s ‘dieselgate’ scandal, AIR Index tests for NOx emissions during real-world urban driving.
The initial tests show significant discrepancies between real-world emissions and those claimed by some manufacturers.
Why is NOx bad?
There’s actually no such gas as NOx. It’s an umbrella term for various polluting nitrogen oxides, including Nitrogen Dioxide (NO2), Nitrous Oxide (N2O) and Nitric Oxide (NO) – which reacts in the atmosphere to become NO2.
Oxides of Nitrogen are associated with respiratory illnesses, acid rain, and global warming. One analysis defines N2O as being 300 times worse, as a greenhouse gas, than Carbon Dioxide.
City authorities across Europe are therefore being urged to reduce NOx emissions. Will the diesel Discovery 5 be one of the few non-hybrid vehicles to be allowed in future Low Emission Zones?