Question to the Department for Transport:

To ask the Secretary of State for Transport, what assessment her Department has made of the impact of excess nitrogen oxide (NOx) emissions from diesel vehicles using defeat devices on UK air quality.

The Department for Transport is the department responsible for setting and enforcing standards for NOx emissions from diesel vehicles. The Market Surveillance Unit within the Driver and Vehicle Standards Agency is undertaking a programme looking at possible non-compliant diesel emissions in Euro 5 and Euro 6A/B/C diesel cars and vans where there is reason to believe that they contain a prohibited defeat device.

DVSA investigations will include assessing the impact of excess NOx emissions from non-compliant vehicles.

This programme of investigations is ongoing, and the Department will publish outcomes of these investigations when completed.