URL: https://democracy.bathnes.gov.uk/ieDecisionDetails.aspx?ID=2461

Decision Maker: Cabinet

Outcome:

Is Key Decision?: No

Is Callable In?: Yes

Purpose: Bath and North East Somerset Council (B&NES) has achieved sustained compliance with nitrogen dioxide (NO?) legal limits following the introduction of the Clean Air Zone (CAZ) in March 2021, in response to a Ministerial Direction under the national NO? programme. The scheme has resulted in average NO? levels reducing by approximately 40% across the network compared to the 2019 baseline.   The report sets out the Council’s proposed approach to progressing to the next stage of the project in order to maintain compliance with the national NO? programme, in line with Central Government requirements.

Content: Bath and North East Somerset Council (B&NES) has achieved sustained compliance with nitrogen dioxide (NO?) legal limits following the introduction of the Clean Air Zone (CAZ) in March 2021, in response to a Ministerial Direction under the national NO? programme. The scheme has resulted in average NO? levels reducing by approximately 40% across the network compared to the 2019 baseline.   The report sets out the Council’s proposed approach to progressing to the next stage of the project in order to maintain compliance with the national NO? programme, in line with Central Government requirements. That Cabinet:   1)  Notes the achievement of sustained compliance with NO? legal limits across Bath.   2)  Approves progression to State 4 modelling and development of compliance with the national NO? Programme.   3)  Delegates authority to the Director of Place Management to progress procurement, modelling and any required stakeholder engagement associated with State 4 modelling. In 2017, the UK Government published its Air Quality Plan for tackling roadside NO2 concentrations, identifying a legal requirement for local authorities to take action in the shortest possible time where exceedances were identified. Bath and North East Somerset was one of twenty eight authorities directed by Government to develop a local Clean Air Plan (CAP) due to forecast exceedances of the annual mean NO2 limit of 40 µg/m3.   Local modelling and national assessments indicated that, without intervention, NO2 exceedances in Bath would persist until at least 2025. The primary source of exceedance was road transport emissions, exacerbated by Bath’s unique topography, with a valley setting and constrained street network leading to the trapping of pollutants.   In response, B&NES developed a Full Business Case (FBC) in 2020, identifying a Class C Clean Air Zone (CAZ) alongside targeted traffic management interventions as the preferred option to achieve compliance in the shortest time possible. The CAZ was implemented on 15 March 2021, supported by Government funding totalling approximately £20.044m across feasibility, implementation and Clean Air Fund programmes.   The scheme introduced daily charges for higher-emission commercial vehicles, alongside complementary measures including bus retrofitting, financial assistance schemes, and traffic management changes in key locations such as Queen Square. Automatic Number Plate Recognition (ANPR) infrastructure was deployed to support enforcement and monitoring.   Since implementation, a comprehensive monitoring network comprising diffusion tubes, automatic analysers and ANPR data has been used to track air quality outcomes. Monitoring results have been reported to the Joint Air Quality Unit (JAQU) on a quarterly basis.   Evidence demonstrates that the CAZ has been highly effective in reducing NO2 concentrations. Average NO2 levels have reduced by approximately 40% across the network compared to the 2019 baseline, with no recorded exceedances of the annual mean limit value in recent monitoring years. Reductions have also been observed beyond the CAZ boundary, indicating wider network benefits.   B&NES has successfully progressed through the national NO2 programme stages. State 2 and State 3 assessments confirmed that compliance with legal NO2 limits has been achieved and maintained. The authority is now required to progress to State 4, which requires assessment of whether measures can be modified or removed without risking a return to exceedances.   State 4 modelling involves detailed technical appraisal of future air quality scenarios, fleet and behavioural changes, and local development trajectories. This modelling is essential to:   ·  Confirm that compliance can be sustained without the CAZ. ·  Support negotiations with the Joint Air Quality Unit (JAQU). ·  Provide assurance that vulnerable groups will not be adversely affected.   This modelling must now formally commence to maintain alignment with national timetables and to ensure the authority is prepared for future submissions to government.   Cabinet approval was therefore requested to initiate State 4 modelling. This will involve working with recognised technical partners which will be funded through existing CAZ Programme ringfenced budgets.   While pursuing compliance with the national NO2 programme outcomes, the Council remains firmly committed to protecting the health of residents over the long term. The transition into State 4 modelling will not diminish the authority’s ambition to improve air quality further. Not to progress to State 4 modelling – this option was discounted as it is a requirement of the National Clean Air programme and the Ministerial Direction under which we are mandated to comply.

Date of Decision: July 2, 2026