2022 Annual Report for Defra sets out progress in evaluating Local NO2 Plans
Reducing and maintaining nitrogen dioxide (NO2) concentrations to within statutory limits is essential to curtailing impacts of poor air quality on public health, such as the development of respiratory conditions. Across England, Local Authorities with persistent exceedances of roadside NO2 concentrations are working in accordance with Government requirements to develop and implement Local 2 Plans, with the aim of reducing these NO2 concentrations to within statutory limits in the shortest possible time.
Ipsos, together with the Institute for Transport Studies (ITS) at the University of Leeds has been evaluating the impact of these Local Plans on air quality and behaviours since 2019. The work is being conducted on behalf of, and in collaboration with, the Joint Air Quality Unit (JAQU), a joint unit between the Department for Transport (DfT) and the Department for Environment, Food and Rural Affairs (Defra).
Some Local Authorities have implemented Clean Air Zones (CAZs), that require certain categories of vehicle to pay a charge if they exceed emission standards, whilst others have introduced a non-charging approach, including measures such as traffic management and support for specific vehicle types.
The 2022 Annual Report was published last week and provides some key findings for the evaluation.
Research with residents and businesses within and around the Bath and Birmingham CAZs, shows that they have led to significant changes in travel behaviour, such as upgrading vehicles or taking a different route to travel. Such behaviour change is reflected in the shift towards less polluting vehicles travelling into the CAZ areas in Birmingham and Bath. Evidence of a cleaner fleet was also observed in the Portsmouth CAZ area. The evaluation’s modelling of emissions in these three areas suggest that NOx emissions were substantially reduced, but this is not yet detected through step-changes in measured air quality in these locations. Several factors may be behind this lack of step change, including varying weather conditions and traffic demand returning to pre-pandemic levels . Crucially however, the lack of a step-change in air quality measurements, despite traffic levels having returned to pre-pandemic levels across all locations analysed in this report, is a positive result. This is because it suggests that the CAZs helped ensure that air quality did not deteriorate from the pandemic baseline.
The Central Evaluation will continue to explore the longer-term impacts of CAZs in Birmingham, Bath and Portsmouth, and the impacts of plans in other LAs, including those not implementing a CAZ.
