PARLIAMENTARY WRITTEN QUESTION
Motor Vehicles: Exhaust Emissions (28 April 2016)

To ask the Secretary of State for Environment, Food and Rural Affairs, what estimate of real world diesel emissions for Euro 6 vehicles, relative to the laboratory test limit, was used in the evidential basis supporting her Department's conclusion that eight air quality zones would not comply with Nitrogen Dioxide limits by 2020 if no action is taken.

Asked by:
Kerry McCarthy (Labour)

The modelling used for the air quality plan was based on the best available data and uses the latest COPERT (Computer Programme to Calculate Emissions from Road Transport) (4v11) factors to calculate emissions from diesel cars.

These COPERT factors reflect that there is a difference between laboratory testing of vehicle emissions and real world emissions. They assume Euro 6 diesel cars are, on average, emitting 2.8 times the level of emissions allowed for the Euro 6 standard.

In May, the Government will present the results of its vehicle testing programme (www.gov.uk/government/publications/vehicle-emissions-testing-programme-conclusions) to European Research for Mobile Emission Sources (ERMES), the body responsible for collating vehicle emission data, to inform its updated emissions factors later this year. This will ensure that EU-wide emission factors continue to focus on the latest data updated on the basis of real world testing.

Answered by:
Rory Stewart (Independent)
4 May 2016