Question to the Department for Transport:

To ask His Majesty's Government what assessment they have made of local authorities introducing traffic filters to reduce nitrogen dioxide pollution; and of whether this displaces such pollution from city centres to city peripheries; and what plans they have, if any, to amend the regulations relating to the use of traffic filters in such circumstances.

Under the NO2 Programme, local authorities with persistent exceedances of nitrogen dioxide concentrations are required to assess and implement measures to reduce and maintain nitrogen dioxide levels to within legal limits in the shortest possible time. Local authorities make their assessment using rigorous transport and air quality modelling. This is informed by impact assessments, which include the consideration of traffic displacement, and extensive public consultation. Measures may include implementation of a Clean Air Zone by a local authority using powers under the Transport Act 2000. Clean Air Zones reduce the frequency of journeys taken by the most-polluting vehicles within the zone and can increase vehicle turnover to cleaner vehicles.

Local authorities monitor NO2 reduction measures throughout their lifetime in collaboration with the DfT/ Defra Joint Air Quality Unit.