To ask the Secretary of State for Transport, what steps his Department is taking to monitor the compliance of local authorities establishing clean air zones with the policy paper entitled Clean air zone framework, updated on 6 October 2022.

The Joint Air Quality Unit’s evaluation programme aims to ensure that the nitrogen dioxide (NO₂) programme is delivering its stated aims.

There are two main strands to the evaluation programme:

Local monitoring: all local authorities are required to monitor changes to air quality and traffic (traffic count and Automatic Number Plate Recognition fleet data) in the relevant areas and report this data to the Joint Air Quality Unit quarterly. Local authorities may choose to conduct further monitoring activity or evaluate the wider impacts of their air quality improvement measures in more detail.

Central evaluation: this aggregates data from across the different local authorities implementing air quality improvement measures. Where possible, this is used to inform the development and delivery of air quality improvement measures as well as providing a stronger evidence base for air quality policy making. Traffic data will be analysed to provide percentage compliance rates of each vehicle class in regards to the Clean Air Zone emissions standards i.e. percentage of Euro 6 vehicles.

The second annual report for the evaluation was published on 12 May 2022 and covers the evaluation findings from 2021, including early analysis following the launch of the Bath Clean Air Zone.

In addition, the UK’s Air Quality Standards Regulations 2010 require the UK to undertake air quality assessment to assess legal compliance against air pollutant concentration limit and target values and report the findings and associated data on an annual basis. This assessment is done for all local authorities not just those establishing Clean Air Zones.