A clean air zone for Bristol

The main pollutants responsible are Nitrogen Dioxide (NO2) and particulate matter (PM10). Defra’s data on air pollution suggests that it is falling, but this finding has been criticised by, among others, the UK Green Party, which has claimed that the department’s findings were based on dishonest data supplied by car manufacturers. However, in the short term at least, it is certainly the case that air pollution remains above legal limits in several cities across the UK, including Bristol, where NO2 is currently thought to be responsible for around 300 deaths per year across the city.

Transport

Much of the air pollution in the UK, and elsewhere, is produced by transport, particularly diesel vehicles. Nitrogen Dioxide is produced when Nitrogen Oxide (NOX) reacts with the air after it is emitted by vehicle exhausts, but vehicles also emit methane and low-level ozone as well as being a contributor to climate change. Currently, transport is responsible for over 20 percent of UK carbon (CO2) emissions, and that figure is growing both nationally and locally. Among vehicles, diesel trucks and buses are the biggest culprits, but diesel cars, through sheer weight of numbers, are also major emitters also.

In Bristol, transport is thought to be responsible for around 36 percent of the city’s total CO2 emissions, while emissions from buildings also contribute. The situation in Bristol is getting worse primarily as an effect of the economic development of the city over the last 20 years, with greater numbers of people travelling into the city centre, many of them on the roads. This in turn has produced a situation in which air pollution in some districts of the city is almost twice the legal limit.

Bristol City Council’s response

Bristol City Council has a statutory duty to monitor air pollution, which it does through a number of monitoring sites across the city.

In November 2016, the Full Council unanimously supported a motion to develop an air quality action plan and to see guidance from central government on establishing a Clean Air Zone (CAZ). In July this year, the government published a national plan for reducing roadside NOx pollution, requiring Bristol and 23 other local authorities to undertake a feasibility study in order to identify the best option to deliver compliance with legal limits for NOx, with a deadline for delivery of the results of the study of 31st March 2018. Bristol City Council Mayor Marvin Rees responded to this by establishing a working group on air pollution, which will work within the council’s existing Congestion Group.

Meanwhile, alongside the discussions around the potential for a Clean Air Zone, the council is also developing a Clean Air Action Plan which will complement other plans on transport being developed by the council and also by other local authorities working with Bristol in the West of England Partnership (South Gloucestershire Council, Bath & North East Somerset). The Clean Air Action Plan will also incorporate improvements to the planning system aimed at addressing air pollution concerns from new developments as well as laying the foundations for the introduction of new clean transport such as electric vehicles (EVs) and charging infrastructure. Other ideas under discussion are restrictions on freight vehicles in the city and the establishment of a totally clean bus and taxi fleet.  

Options for Clean Air Zones (CAZs)

While the government’s directive gives Bristol the go-ahead to proceed with a Clean Air Action Plan, the specific idea of establishing a Clean Air Zone is more intricate, hence the discussion between the council and central government around this particular issue. The government published a draft framework for Clean Air Zones in May, which sets out the main guidelines for local authorities considering implementing them. Essentially, a Clean Air Zone is an area in which targeted action is undertaken to improve air quality, prioritising resources and coordinating efforts in order to deliver health benefits while also continuing to support economic growth. It is this emphasis on maintaining and supporting economic growth that makes the Clean Air Zone discussion a particularly intricate one, considering the question of how economic growth can continue but in a cleaner form.

In Bristol, which is the second most congested city in the UK outside London, the major problem is transport. It is a problem that successive councils have wrangled with continuously over several decades, with accompanying continuous argument among the general populace, in which a number of different interests, for example motorists, cyclists and public transport, regularly clash.

Clean Air Zones can be delivered in two forms, specifically charging and non-charging. In a charging CAZ, a financial charge is paid by drivers for access to the area covered by the CAZ. In a non-charging zone, this charge doesn’t apply and doesn’t appear in the range of targeted actions implemented by the local authority.

Bristol City Council and South Gloucestershire District Council have already secured government funding of £498,000 to support a feasibility study into a Clean Air Zone, with Bristol taking the lead role in the initiative. The study will be undertaken by consultants CH2M with the University of the West of England (UWE) Air Quality Management Unit participating in an advisory role. It consists of three phases, the first of which, involving analysis of data to select a range of possible options, has already been completed.

The second phase is currently running and will be completed in November. This phase will involve detailed traffic and air quality modelling aimed at assessing the four possible options identified by Phase 1, alongside their potential economic impacts and costs. The final option selected in this Phase 2 will then be subjected to further detailed assessment in Phase 3, between December 2017 and February 2018. This will consider the financial, health, transport, social, economic and environmental aspects of a CAZ, with special attention given to the possible economic impacts on low income households in the central and outer areas of the city, and also on small businesses, particularly those currently reliant on diesel vehicles, including taxi and private hire firms and those utilising buses and vans.

The options recommended by CH2M in Phase 3, identified as four classes, were as follows:

Class A non-charging - buses, coaches, taxis, private hire vehicles
Class A charging – buses, coaches, taxis, private hire vehicles
Class B charging – buses, coaches, taxis, private hire vehicles and HGVs
Class C charging – buses, coaches, taxis, private hire vehicles, HGVs and LGVs
Class D charging – buses, coaches, taxis, private hire vehicles, HGVs, LGVs and cars

The areas under consideration for implementation of a CAZ fall within either Bristol City centre as a specific area or within the existing Bristol Air Quality Management Area (AQMA). This was established in 2001 and covers the city centre as well as important arterial routes that feed into it. The AQMA is where the major city centre workplaces are, where many of Bristol’s retail and leisure sites are located and also where the city’s main hospital and literally dozens of schools are also located. Another option is a large CAZ covering the continuous urban area covered by both Bristol City Council and South Gloucestershire Council. Therefore the possible areas selected by CH2M for a possible CAZ are:           

Small CAZ – Bristol City centre
Medium CAZ – The Bristol AQMA, the Bristol AQMA plus Kingswood and Warmley, and Bristol AQMA plus Kingswood and Warmley but with AQMA considered separately.
Large CAZ – The Bristol/South Gloucestershire continuous urban area

From these, CH2M recommended four options, which are currently being discussed under Phase 2. These are:

Medium sized, CAZ Class C (based on the existing Bristol Air Quality Management Area (AQMA) including all vehicles except cars)
Medium sized CAZ Class D (Bristol AQMA including all vehicles)
Small sized, CAZ Class C (Bristol City Centre including all vehicles except cars)
Small sized, CAZ Class D (Bristol City Centre including all vehicles)

These four options do not include the Bristol/South Gloucestershire continuous urban area, which includes significant areas of the city that already meet legal air quality requirements. Furthermore, a larger CAZ would have a larger impact on low income households. It could also potentially negatively affect government funding support, would be costly to implement and would require a longer transition time. At the present time, it seems that the medium sized options are not being considered either, as a small CAZ would have enough of an impact on journeys through the South Gloucestershire area to achieve compliance with legal air quality requirements.

What’s next?

Interestingly, First Bus are reacting to this process with a programme of replacing the Bristol bus fleet with Euro 6 compliant vehicles. Most of these are still diesel, but some of them are powered by hybrid diesel engines and natural gas. Meanwhile, the deadline of February 2018 will be the date that the final option is approved by Mayor Marvin Rees, with full implementation of it occurring at some point after that.