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Decision details

Proposed Change to Maidstone AQMA and Request to Consult on New Air Quality Action Plan

Decision Maker: Executive

Decision status: For Determination

Is Key decision?: No

Is subject to call in?: Yes


Air quality in Maidstone has improved significantly in recent years to the extent that most of the Borough is now in compliance with all air quality objectives.  The only area in which any objective is exceeded is Upper Stone Street.  The current Air Quality Action Plan (AQAP) will shortly need to be updated.  It is proposed that, prior to updating the AQAP, the current Air Quality Management Area (AQMA) be revoked and a new AQMA should be declared which more closely reflects the current area of exceedance.  The new AQMA would cover Upper Stone Street from Wrens Cross to Old Tovil Road.  The new AQAP could then be more focussed on the Upper Stone Street Area.  The report includes a draft list of potential actions for inclusion in the new AQAP.  Permission is requested to hold a public consultation on these actions.



1.  That the revocation of the old Air Quality Management Area (AQMA) in Maidstone which will require an Air Quality Management Area Revocation Order to be issued, be agreed.


2.  That the declaration of the proposed new AQMA in Maidstone, covering Upper Stone Street, as described in the report of the Senior Scientific Officer, which will require a new Air Quality Management Area Order to be issued, be agreed.


3.  That permission be granted to hold a public consultation on the proposed actions given in the report to be included in a new Air Quality Action Plan.


Reasons for the decision:

Maidstone first declared an Air Quality Management Area (AQMA) in 2008. The AQMA encompassed the whole of the Maidstone conurbation, including a number of areas of exceedance of the NO2 annual mean objective. These so called ‘hotspots’ included the High Street, Upper Stone Street, Well Road, the Junction of Tonbridge Road and Fountain Lane, and the Wheatsheaf Junction. However, the AQMA also included many areas where there were no exceedances of any air quality objectives.


In 2018, the 2008 AQMA was replaced with a newer, smaller AQMA, more closely aligned to the actual areas of exceedance of the NO2 annual mean objective, which followed the carriageways of the main roads through the district. The modelling on which the new AQMA was based was done in 2016, and based on the data from 2014, which was the most up to date available at the time.


Air quality in Maidstone has improved considerably in the last five or six years.  This local trend reflects a national trend of improvement in air quality. The primary drivers of this trend of improvement are the introduction of Euro VI engines, particularly in HGVs, the increased uptake of electric and hybrid vehicles, and a decrease in the popularity of diesel passenger cars. At the same time, large numbers of the oldest most polluting vehicles are being taken out of the vehicle fleet as they reach the end of their service lives.


The result of these improvements over several years is that most of the areas of Maidstone which were previously recognised as air quality hotspots have now come into compliance with all air quality objectives. 


The remaining area of concern is Upper Stone Street.  Upper Stone Street has also seen a trend of decreasing pollution levels, however, levels there were particularly high, and there is still an exceedance of the annual mean objective for nitrogen dioxide.  As part of our ‘review and assessment’ function, under the Environment Act, 1995, monitoring in Upper Stone Street includes continuous automatic monitoring of NO2, as well as six diffusion tube sites.  PM10 and PM2.5 are also monitored but the objectives are not exceeded.


Our Air Quality Action Plan, (which is currently called the ‘Low Emission Strategy’) is due to be updated. The drafting of the Low Emission Strategy coincided with the end of the Council’s 2008 to 2015 Carbon Management Plan, and thus included a few actions related to ‘Carbon Management’ in addition to the air quality actions.  It was therefore called the Low Emission Strategy to distinguish it from the usual Air Quality Action Plan.  The Council now has a Climate Change Strategy, agreed in October 2020, therefore the new Action Plan, which will not attempt to duplicate actions being undertaken in the Climate Change Strategy, will only contain actions directed specifically at local air quality, and will simply be called the Air Quality Action Plan.


MBC has commissioned Air Quality Consultants (AQC) Ltd to review the current AQMA and previously used AQC to undertake air quality modelling in 2018.


AQC’s report has confirmed that the majority of the current AQMA could now be revoked, with the only remaining area of exceedance being in Upper Stone Street, between Wrens Cross and Old Tovil Road.


The annual mean objective for NO2 applies primarily at residential property. A different objective applies to people outside, eg pedestrians, shoppers etc, and this objective is not exceeded anywhere in the Borough.


It has been estimated that the current AQMA contains about 1400 residential properties.  AQC’s report suggests that there are only 53 residential properties in Upper Stone Street in an exceedance of the NO2 annual mean and these properties would need to remain in an AQMA when the existing AQMA is revoked.


The annual mean objective for NO2 is 40µgm-3. Of the 53 residential receptors exceeding this objective, 44 are in the range 40 to 60µgm-3 and a further 9 are at a level of over 60µgm-3.


AQC then went on to consider the effect of improvements to the bus fleet on air quality in Upper Stone Street.  An ANPR camera survey was undertaken in order to establish baseline fleet composition and used this to model a baseline year of 2022. 


Owing to the ongoing trend of improving air quality, the modelling predicted a reduction in the number of residential receptors in an exceedance of the annual mean objective for NO2 from 53 to 30. This would occur in the absence of any additional interventions.  Of these 30, 27 will be in the range 40 to 60µgm-3 and the remaining 3 will be at a level in excess of 60µgm-3.


If the buses operating on Upper Stone Street were restricted to Euro VI only, the 30 residential receptors in an exceedance would  be cut to only 18, of which 15 would be in the range 40 to 60µgm-3 and the remaining 3 would be at a level in excess of 60µgm-3.  The modelling suggested that allowing only electric buses to operate in Upper Stone Street would not currently bring about an additional reduction in the number of receptors in the area of exceedance, however, logically it would offer additional air quality benefits which would help to bring forward compliance with the objectives.


AQC’s conclusions are primarily based on consideration of data from 2019, which was the last year unaffected by the impact of the COVID pandemic.  Data from 2020 and 2021 are lower than 2019, mainly as a result of COVID restrictions, however, owing to the long-term trend of improvements in air quality, we would have expected somewhat lower levels even without the COVID restrictions.


MBC has already considered, in some depth, potential actions for improving air quality in Upper Stone Street in 2019, when a range of options was investigated by consultants Arcadis and ITP. A long list of measures which had the potential to improve air quality in Upper Stone Street was evaluated by the consultants and nearly all of them were rejected because they were either impractical, too expensive, or likely to simply displace the problems to a different location. One option previously considered and rejected by Members as part of this project was a Clean Air Zone.  Our consultants demonstrated that the Clean Air Zone would actually only have a marginal benefit, and therefore it is assumed that this is still an option that Members would still not wish to pursue.


However, as a result of the above investigations, MBC has recently tightened parking restrictions in Upper Stone Street.  Single yellow lines have been replaced with double yellow lines, and loading restrictions were also increased (no loading between 7:00am to 8:00pm). MBC also worked with KCC to ensure that new trees being planted in the area were optimised for air quality in terms of species and spacing.


It is intended that the Air Quality Action Plan should primarily be focussed on the main problem area, and therefore, following the recommendations of AQC Ltd, the boundaries of the AQMA should now be changed to reflect more accurately where the problem area currently is, namely, Upper Stone Street.


The actions below are to be included in the Action Plan. There will be a public consultation on these actions, which will be developed in the light of consultation responses. Note that some actions are continuations of actions which have been successfully worked on previously.


Where possible, actions will be focussed on addressing the specific air quality issue in the new AQMA.  Some actions, however, will necessarily be more generally applied, e.g. the Clean Air For Schools programme, which should result in Borough-wide air quality improvements.


Delivery of these actions will require MBC to work with other stakeholders, of which the main one will be KCC. Others will include DEFRA, local bus companies, and local schools.


Following the declaration of the AQMA, DEFRA guidance states that the Air Quality Action Plan should ideally be produced within 12 months.


Actions to be included in the consultation are:


Improvement to bus fleet in Maidstone, with special emphasis on services operating on Upper Stone Street.  The report from AQC estimates that approximately 16.4% of the NOx pollution on Upper Stone Street originates from buses.  Maidstone’s bus fleet is very old. Approximately 72% of the pollution from buses on Upper Stone Street arises from Euro II, Euro III and Euro IV buses. KCC has identified Maidstone as a priority corridor for electric bus upgrades, but this is dependent upon the award of government funding. In the meantime, we would like to see the best available buses operating on Upper Stone Street. Legal advice has suggested that no improvements to the bus fleet could be achieved without the involvement of KCC, other than via informal arrangements with the local bus companies.


Review of Air Quality Planning Guidance to reflect updated air quality information.  The current Air Quality Planning Guidance is out of date and needs to be updated to reflect current best practice and take account of the new Future Homes Standard. This may include increasing the requirement for AQ mitigation in and around the new AQMA, but we will need to ensure that the requirements are appropriate for the current air quality situation.  The guidance must aim to prevent development having a negative impact on the AQMA, for example, by use of developer contributions to fund air quality improvement schemes (eg car club, bike hire schemes, travel plans etc, or similar). This review will need to take account of the status and content of the new Local Plan at the time it’s undertaken.


Review of Taxi Policy to include consideration of whether any agreed improvements to vehicle standards could be brought forward, and investigation of what support might be available to facilitate these improvements.


Information campaign to residents of the new AQMA.  A grant has been applied for from DEFRA to fund this action and we are waiting to hear whether the funding has been approved.


Extension to the Clean Air For Schools (CAFS) programme.  Officers are currently developing a digital air quality resource, with funding from a DEFRA air quality grant awarded in 2021. This will start to be rolled out to schools in 2022.


A campaign of anti-idling signage across the Borough, focussing on schools and other known or identified problem areas.  Officers are currently working to identify suitable locations for anti-idling signage and some signs have already been deployed.


Consider discount on resident’s parking for EV vehicles.  It is anticipated that it should be possible to offer this in the next 3 to 5 years (and conversely, perhaps an increased tariff for the most polluting vehicles) Environmental Health will continue to liaise with parking to influence future reviews of Parking Strategy.


Review provision of EV parking in Council car parks.  Whilst data currently shows that the current provision of 18 EV charging points is underutilised, this will be closely monitored and expanded to meet demand over time.


Continuation of MBC sponsorship of the Walk on Wednesday Scheme.  MBC currently supports the Kent Messenger Walk on Wednesday scheme, which encourages schoolchildren to walk to school.


Across the Mid-Kent Environmental Health Service, other actions are being considered, which might be adapted to have relevance in Upper Stone Street.  These include, promotion of the Kent Revs e-van loan scheme, e-bike hire schemes, car clubs, increased use of travel plans, live information bus stops, and signage to notify drivers that they are in an AQMA.


Consideration has also been given to the possible introduction of a 20mph speed limit in Upper Stone Street (and adjoining side streets).  AQC’s report includes an assessment of this idea, based on relevant literature, and concludes that the impact of a 20mph speed limit on air quality in Upper Stone Street is likely to be very small, but beneficial. The report also notes that 20mph speed limits can offer other benefits apart from their impact on air quality, e.g. reduced noise and improved safety. However, due to uncertainty about the implementation and enforcement of such a scheme, it has not been added to the list of measures to be consulted on.


Consultation Results and Previous Committee Feedback


This issue was considered by the Communities, Housing and Environment Policy Advisory Committee on 11 October 2022, and the Committee supported the recommendations of this report.


Changes to the AQMA and the preparation of an AQAP require consultation. DEFRA is the key statutory consultee in both cases. Other consultees are:


·  The Environment Agency.

·  Highways England.

·  The County Council.

·  Neighbouring Authorities.

·  Bodies representing local businesses.

·  The public.


Officers from Mid-Kent Environmental Health and the Council’s Policy Team will organise the consultation, following approval of the recommendations in the report.


Alternative options considered:

To do nothing.  However, unless the Action Plan is updated, the Council will fail to comply with its statutory duties on Local Air Quality Management.


To leave the boundary of the AQMA unchanged and just update the action plan. However, there is not really any advantage in having a larger than necessary AQMA.  In the view of officers, updating the AQMA to reflect changing pollution levels is good practice.


The preferred option is to revise the boundary of the AQMA in line with AQC’s recommendations.  The Action Plan can then be updated with a particular emphasis on addressing the air quality issues specific to the new AQMA. Officers will undertake a public consultation on the measures listed in the report.  This option best complies with the current statutory guidance.  As part of the process of revoking the old AQMA and declaring the new AQMA, MBC is required to consult with DEFRA, which has been done through MBC’s Annual Status Report to DEFRA which DEFRA has accepted. The smaller AQMA will more accurately reflect the true air quality picture in Maidstone, as compared to the current AQMA.  It will also help to keep the new Air Quality Action Plan focussed on the relevant area.


Publication date: 28/10/2022

Date of decision: 26/10/2022

Decided: 26/10/2022 - Executive

Effective from: 05/11/2022

Accompanying Documents: