To meet national air quality objectives, local authorities must regularly review and assess air quality in their areas. If a location is found where the objectives are not being achieved, the local authority must declare the area as an Air Quality Management Area (AQMA) and develop an Air Quality Action Plan to reduce air pollution.
An Air Quality Management Area was declared in 2006 to address traffic related nitrogen dioxide (NO2) concentrations in excess of the annual mean Air Quality Standard objective. The AQMA encompassed six properties on the western side of the Thoroughfare/Melton Hill arm of the junction with Lime Kiln Quay Road, Thoroughfare and St John’s Street in Woodbridge (Woodbridge Junction).
A Further Assessment was completed in 2007 confirming that the AQMA should be retained. This assessment concluded that approximately 90% of the NO2 emissions are from the vehicle exhausts of local traffic, both stationary and moving vehicles.
An Air Quality Action Plan (AQAP) was prepared for the AQMA following public consultation, first published in May 2011. The Action Plan consists of 20 measures that could be undertaken at the junction to ease the congestion or reduce the overall traffic flows, in turn reducing NO2. The measures can be considered within two main categories; ‘on the ground works’ and 'softer measures’.
The ‘on the ground works’ started with the installation of a new computerised Microprocessor Optimised Vehicle Actuation (MOVA) system to the traffic lights whose aim is to reduce congestion and therefore queue lengths. This reduced the extreme queue lengths at each arm of the junction but not the average number of vehicles queuing at the junction.
A feasibility study was completed for the 5 measures remaining in the Action Plan classed as ‘on the ground works’. The study had 2 recommendations; to install a weather station for 3 months within the AQMA, and to trial holding back traffic a distance from the lights (therefore away from the AQMA) and pulse it through.
The weather station was installed from July to November 2015 and results showed that the topography of the junction itself is a major factor in relation to NO2 concentrations. The layout of the junction is such that the wind speed is much lower than expected and the wind direction is slightly altered from the norm. The study suggested that vehicle emissions are ‘funnelled’ along Melton Hill away from the junction, and then dispersed very slowly due to the low wind speeds and canyon like effect of the buildings on both sides. Emissions therefore tend to accumulate rather than disperse, resulting in higher than expected NO2 concentrations close to the traffic lights on the western side of Melton Hill/Thoroughfare – within the AQMA.
Work on the ’softer measures’ within the AQAP (for example improving accessibility to bus timetables, promotion of car sharing schemes, travel plans for businesses and schools, integration with the planning system and raising air quality awareness) has continued throughout.
NO2 concentrations within the AQMA began to fall in 2006, and from 2014 have been below the air quality objective with a continuing trend of reduction.
Following instruction from the Department for Environment, Food and Rural Affairs (Defra), a revocation assessment was undertaken to confirm whether this was the correct course of action for the AQMA. The assessment report considered national, regional and local factors and predicted future NO2 concentrations within the AQMA for a 5-year period using both 2019 and 2020 measurements. NO2 concentrations within the Woodbridge AQMA have been consistently below the Air Quality Strategy objective since 2014, and the assessment demonstrated that this is likely to continue into the future. It concluded that there is confidence the Woodbridge AQMA can be revoked and recommended that this should happen in line with Defra requirements. The report was sent to Defra within the 2021 Air Quality Annual Status Report for the district Air Quality Reports » East Suffolk Council.
NO2 concentrations within the AQMA have reduced to below the Air Quality Standard objective without a discernible change in traffic volume. It is hypothesised that the general fleet emissions reductions, achieved as older vehicles are replaced with newer, cleaner ones, is the primary cause. This, alongside the incremental improvements brought about through the implementation of measures within the AQAP, led to the potential for revocation of the AQMA.
The findings of the revocation assessment received approval from Defra, who advised that East Suffolk Council should now proceed with the revocation. The revocation assessment was taken to the Council’s Cabinet meeting on 3 May 2022 where they unanimously accepted the next steps – to proceed with a public Consultation.
A Public Consultation was undertaken asking for views and comments on our intention to revoke the AQMA declared at the Woodbridge Junction. The Consultation ran for 6 weeks and ended on 11th July 2022.
The Council received 9 responses to the consultation, the results have been collated and placed on the ESC website at Revocation of AQMA Woodbridge Results 2022 » East Suffolk Council. All respondents were replied to individually.
On 29th September 2022 the AQMA declared at the Woodbridge Junction was revoked following the findings of the revocation assessment and the results of the public consultation. View a copy of the Revocation Order.
Our air quality duties do not end now that the AQMA has been revoked: