In its Air Quality and Road Transport report, the foundation pointed out that road transport contributed 30% of the overall nitrogen oxide output and 20% of all particulate matter in the UK. The estimated cost to the NHS of diseases related to poor air quality from road transport is between £4.5bn and £10.6bn per year.

Defra has identified 600 Air Quality Management Areas across the UK, of which many require a 50% reduction in transport emissions to bring levels below health limits, while some require 75-80% reductions. There is also widespread non-compliance with annual average limits for nitrogen oxide (NO2) content.

The report says this is caused by an inability for towns and cities to handle congestion, and that the Euro 1-5 emissions standards were not being met in real-world use. With diesel engines now the second-largest source of NO2 in the UK, the Foundation suggests proposed limits with the next Euro 6 standards, which also assess real-world use, would be wise.

The solution suggested includes three pillars – to Avoid road transport where possible, encourage a Shift to less polluting modes such as EVs and to Improve the performance of existing technology. Notably, it says, downsized petrol engines as well as hybrids and electric vehicles, recognising not just CO2 emissions and climate change, but air quality too. 

Stephen Glaister, director of the RAC Foundation, said: ‘Whilst heavy-duty vehicles – buses and lorries – are still the main source of NOx emissions, the contribution from diesel cars has increased rapidly over the last decade because of the “dieselisation” of the car fleet.

‘This is a consequence of the focus on climate change. The automobile industry’s response to the European average new car CO2 emissions targets of 130 g/km by 2015 and 95 g/km by 2021 has been to make more diesel cars, as these are more fuel-efficient than their petrol counterparts. And greater fuel efficiency equals lower CO2 emissions.

‘Unsurprisingly, individual and fleet buyers have responded by choosing diesel, enticed not only by the prospect of reduced fuel costs, but also by lower rates of Vehicle Excise Duty and company car tax incentives, which both reward low-CO2 options.’