This research was conducted by PwC.
“The US investigation into emissions from diesel cars has drawn attention to difference between emissions performance during tests and real world driving. Some commentary confuses the issue of discovery of actions to undermine the tests, and the well-known issue of the difference between test and on road emissions. Car makers and governments were aware of the latter and have published research on this since at least 2011.
The attention has opened up an old question – which is better for the environment, diesel or petrol? And if diesel is not better, why have lower taxation for diesel vehicles? In this blog I show how to use natural capital accounting to understand the problem and create better balanced incentives.
The trade-off between greenhouse gases and local air pollution
Here in the UK, incentives never explicitly favoured diesel. Tax policy was simply based on greenhouse gas performance rather than other local air pollution such as nitrogen oxides (NOx) or particulates. New engine standards, mainly Euro 6, would reduce emissions of NOx from 180 mg /km to 80 mg/km. Also NOx emissions in total in the UK were falling from nearly 3 million tonnes a year in 1992 to under 1 million tonnes in 2015…”
Read on at: PwC.