Update on Clean Air Zone

Councillors on Bath & North East Somerset Council are set to meet at a specially convened cabinet to consider proposals for a clean air zone in Bath.

A report into the future of a proposed clean air zone is currently being prepared ahead of the cabinet meeting at the Guildhall in Bath on Tuesday March 5.

Last December the cabinet received a report updating on a consultation which more than 8,400 people took part in about the zone – thought to be a record number for Bath & North East Somerset Council.

In order to help shape a final decision the council has taken additional time to analyse the responses and the technical modelling in order to prepare a report for the meeting in March.

Last year the council undertook a six-week consultation on a proposal for a clean air zone in the city, which would see charges for higher emission vehicles driving in the zone.

The response to the consultation was unprecedented with almost 20 per cent of the responses arriving in the last few days of the consultation.

london road 1
London Road traffic.


Councillor Bob Goodman, cabinet member for Development and Neighbourhoods, said: “The cabinet is meeting in March, as we said we would, to make a decision about the next stage on a proposed clean air zone. Obviously since the consultation ended it has taken additional time to consider all the responses to this crucial issue facing our city and wider area.

“A clean air zone is an opportunity to improve the air we breathe and to make the city a healthier place for the future and our aim is to be compliant at the same time as having the minimum detrimental effect on our residents and on the city’s economy.”

Bath & North East Somerset Council has been told by the government – along with 27 other local authorities, to reduce levels of nitrogen dioxide NO2 in the air by 2021 at the latest.

A report before cabinet in December noted the unprecedented consultation responses and stated that as a result more time was needed to fully analyse the feedback and undertake further statistical and financial modelling work.

The report identified a number of themes emerging from the consultation including the boundary of the zone, impacts on specific groups of people and potential mitigations.

It recommended a further report with fully costed and modelled options, including mitigations, be reported back to the cabinet as soon as reasonably possible and cabinet agreed to delay the decision until March 2019.


  1. The big issue with the CAZ is that it fails to address the biggest cause of Air Pollution which is congestion. The recent Bath Hacked BreATHe hackathon showed that NO2 levels on London Road stayed around 30um3 when vehicle counts were below 350 vehicles per 15 minutes. Once you hit 400 it jumped to around 60um3. Significantly a modern diesel car still produces 30 times as much NO2 as a modern (20 year old) petrol car. 384,000 vehicles created 16.8M petrol cars worth of NO2 in the ANPR data analysis.

    41% of NO2 produced by diesel cars, 40% by diesel vans. You could have a 96% reduction in NO2 by banning all diesel cars and vans, and requiring all HGVs and Buses to be upgraded to CAT 6 euro, BUT you would still have congestion. It would still not be good.

    The CAZ is a DEFRA construct that encourages people to buy newer diesel vehicles without actually creating behaviour change in the system.

    If you really wanted to solve congestion in Bath, introduce city wide parking control and the workplace parking levy. Use revenue to make buses coming to Bath cheap/free and invest in walking and cycling. Keep the car out of Bath. Discourage the 8,000+ Bath residents from driving to work in Bath. Solve congestion. Don’t ask people to buy a newer diesel car and carry on as before.

    1. I agree with Mr Wyatt’s observation that congestion is probably the root of the problem. But I’m not impressed, however, by the ‘bald’ statistics from the ‘Hacked BreATHe hackathon ‘. As Churchill once observed when having to decide on the optimum war strategy in 1940 “I deprecate, however, placing unbounded confidence in one means of attack (over another), and still more expressing that confidence in terms of arithmetic”. I agree with Winston – statistics gathered on a narrow set of measurables, assumed to be salient to the problem, are the third evil of ‘lies, damned lies and statistics’.
      I also disagree with Mr Wyatts broad-brush condemnation of the diesel engine. NO2 is not the only, or even primary, hazard from car emissions. Poorly serviced petrol engines can be equally polluting, and quite likely to be a bigger contributor to the dirty atmosphere than a well-serviced diesel engine.

      Anyone who is a regular two-wheeled traveller in Bath doesn’t need a statistician to point out the obvious – vehicles waiting at traffic lights, queueing for parking, stuck behind parked delivery lorries or inconsiderate “I’ll only be a minute” road (ab)users are the main cause of whatever problems we have wrt dirty air. Their engines (diesel OR petrol) are idling inefficiently and their rate of pollutant emissions per metre travelled (the only variable that’s important) is appallingly high. And the worst of these vehicles are the lorries that stagnate on Bathwick Street or the University bendy buses that grind up Bathwick Hill – travel behind one of those whist riding a bicycle or motorbike and you’ll soon know what real pollution is about.

      So, as Mr Wyatt implied, traffic flow is the leading culprit. If the Council is genuinely interested in reducing the traffic pollution in this city it should address its appalling traffic flow. It should forget about reducing the number or types of private passenger vehicles, whatever the ‘confident’ statisticians may infer, and devise inspired traffic management tactics e.g. more roundabouts, fewer traffic lights, more loading bays and zero tolerance of on kerb parking.

      Of course, however laudable the intention, CAZ is really only ‘re-arranging the deckchairs on the Titanic’ by another name, and unfairly charging residents for the privilege of that pretty ineffectual exercise to boot. If the Council genuinely wanted to SOLVE the problem, rather than merely do the minimum to meet its obligations, it would build that bypass that’s been 20 years in incubation. Once again, politics retards progress.

  2. Is it all comforting to know that the decisions on this CAZ for Bath will be made by a ‘cabinet’ comprising eight councillors, only two of whom represent Bath wards? Not very, I suggest.

  3. Starting with my fellow Camden resident’s observation about the possible geographical bias of the Cabinet. The arithmetic is right but I’m less sure about the conclusion. Many people living outside Bath use the city more often and for longer than I do and probably are more affected by the congestion and pollution than I am. Appointees to the Cabinet need the core expertise for their portfolios and the time to devote to them.

    As far as I understand the CAZ is dealing with NOx, not pollution in general, nor climate change and not congestion – the central government imperative and consequent funding rules do not stretch that far. NOx is a hidden enemy because it is undetectable by those breathing it – the transport fumes and smells we are aware of are something different. We did a blog post on this last year (https://camdenresidentsbath.org/2018/02/23/understanding-air-quality/). The less obvious benefit of the CAZ is that it gives us the technical infrastructure (cameras, computers, charging and enforcement) to bear down on the actual cause of the fumes we also object to – vehicle numbers – in due course.

    If the modelling is correct then there will be a small, but hopefully significant, reduction in traffic levels and proportionately less diesel cars like mine, which emit many more fumes and particulates than their petrol equivalents. Hopefully these detectable effects will be enough for users and residents of Bath to push harder for exclusion measures for the worst emitters which are more achievable with the technical infrastructure in place.

    What the Camden Residents Association is asking for are ways to keep vehicles out of the city by providing better alternatives in the right places. We have 5 million visitors each year mostly arriving by road. We don’t have a ring road which could get people quickly to a few peripheral P&Rs from all the radial routes, so we need more, well positioned hubs to serve all the main radial routes in. At present only 40% of radial routes into Bath even have a P&R. If you don’t believe me look here (https://camdenresidentsbath.org/) at our post entitled ‘Latest CAZ news…). Setting these up creatively and supporting them with cleaner mass transport solutions must be the right direction for us.

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