Clean Air Zones - the latest

What is a Clean Air Zone?

As the name suggests, a clean air zone (CAZ) is a defined area in which the relevant local or transport authority seeks to improve air quality by lowering air pollution levels. They are typically located in city centres, which generally have higher levels of pollution, and where there can often be ‘exceedances’ in specific areas where pollution levels are concentrated. Much of the focus of each CAZ is on nitrogen dioxide although particulates (minute particles of tyres and brake pads for example) are also of concern.

Each CAZ applies a financial, daily charge to certain types of vehicle for driving into the CAZ. The systems are facilitated by number plate recognition (ANPR) camera systems on the CAZ perimeter, which are linked to the DVLA database and which identify a given vehicle by reference to its engine age and type and thus whether a charge is due. In simple terms, more modern vehicles with ‘low emission’ engines (such as petrol Euro 4 and diesel Euro 6) and electric vehicles are regarded as compliant, but older vehicles with a poorer emissions profile will likely be non-compliant and a charge will be payable. 

The overall aim of each CAZ is to act as an incentive for road users for either change their driving habits (for example, use public transport instead) and/or change their vehicle to one with cleaner emissions. To assist this, many of the CAPs that accompany the CAZs offer various financial support measures such as grants which road users can apply for to assist with funding retrofit works or new vehicle purchases. Scrappage schemes (to scrap older, non-compliant vehicles) are also available in some areas.

Client Earth and Ella Kissi-Debrah

By way of background, the UK (usually by virtue of certain urban locations) was considered to be in breach of its own air quality regulations which derived from the 2008 EU Air Quality Directive and with successive governments having only limited plans for addressing the issue. Matters have been forced due largely to the actions of environmental pressure group Client Earth, who brought three sets of court proceedings vs the UK Government, all successful, culminating in ‘Client Earth No 3’ in 2017. The regulations together with the outcome of these decisions was in summary to require the imposition of air quality plans which set out measures to ensure local compliance with pollutant limits in the shortest possible time regardless of cost. Ministers instructed c.60 local authorities to develop local proposals (referred to as Clean Air Plans) to address their particular, local air pollution challenges via ‘Ministerial Directions’. A number of the Clean Air Plans developed feature Clean Air Zones.

Separate to the Client Earth proceedings was the tragic death of 9 year old Ella Kissi-Debrah in 2013 which is thought to have contributed to the considerations of politicians and policy makers on clean air issues. The inquest into her death in 2020 ruled that air pollution was a cause of death – for the first time in the UK. Ella lived in close proximity to the South Circular, a major road in London. The coroner found that the exposure to NO2 and particulates at unlawful levels contributed to her development of acute respiratory failure and severe asthma, ultimately causing her death. 

Why not impose less impactful measures?

The concept of a CAZ is recognised to be a significant intervention on the part of local and central government, but one that can be justified by specific local pollution levels.

In general, local authorities have been able, in collaboration with JAQU (a collaboration between the DfT and DEFRA), to develop bespoke Clean Air Plans that suit their local issues and specific local exceedance points. Plans can include a range of complementary measures, perhaps taking in public transport improvements, timing limits (by hour of day) on vehicle movements, walking and cycling initiatives, programmes to encourage the refresh of the local taxi and bus fleet. 

There's a view that changing public attitudes towards green issues will naturally lead to a cleaner vehicle fleet, for example as the nation transitions to electric vehicles and businesses adopt ESG strategies. Nevertheless, the imposition of a CAZ, or the threat of one, may prompt more immediate action. The threat of a Leeds CAZ in 2019/20 was thought to be partially responsible for the significant renewal of the local taxi and bus fleet.

What operational Clean Air Zones are there?

Another CAZ is proposed for Stoke.

* This is the proposed class for Greater Manchester’s future CAZ should it come into place.

** In London’s ULEZ, vehicles must meet their relevant Euro emissions standards which you can find specified here.

Do they work?

There are many external factors that can distort the results of CAZs, nevertheless the results of the early schemes seems to show both reductions in NO2 and increases in ‘compliant’, cleaner vehicles. The initial results of more recent schemes, such as Sheffield and Bradford, will be keenly awaited.

• Bath between September 2019 and September 2022
  • 13.9% drop in NO2 in city centre
  • 13% drop in NO2 in the wider Bath area
  • Chargeable non-compliant vehicles each day dropped from 5.7% of vehicles to 1.3%
• Birmingham between June 2021 and December 2021
  • 13% drop in NO2
  • Vehicle compliance increased from 79.8% to 88.8%

Are Clean Air Zones viable in a post-Covid world?

This is not a legal question as to compliance with air quality law or a technical question as to pollutant levels, but which falls into the commercial and political sphere. As many of the CAZs were substantially in development and close to launch, the globe became affected by Covid with one impact being to significantly delay the availability of new, clean replacement vehicles for affected businesses to upgrade to. Although vehicle supply chains have partially recovered, opposition to CAZs comes from the cost of living crisis and the effect that charges would have on small businesses in particular. Whatever the considerations, pollution levels likely remain unlawfully high in some of the UK’s urban areas.

What has happened with the ULEZ in London?

In 2008 the London Low Emission Zone (LEZ) went live. At the time, a £5 fine was given to any non-compliant large or heavy vehicle. Nowadays, the daily charge for a vehicle, depending on its weight, that doesn’t meet the LEZ standards is between £100 - £300.

On 8 April 2019, 11 years after LEZ went live, the ULEZ was introduced to the city, and was rapidly expanded to cover “inner London” up to the north and south circular roads. It now covers 4 million people being 44% of London’s population, and is set to expand again on 29 August 2023 to cover all London boroughs. The expansion has been criticised for hitting the poorest households, however it’s defenders point to the fact that 70% of outer London’s poorest households don’t own cars and, as the most deprived areas of London have 13% higher concentrations of NO2 than the least deprived, substantial measures need to be taken to reduce the ongoing and potential negative impact of such bad air pollution.

Despite the political challenges the ULEZ faces, London appears to be a leader amongst other cities. Valérie Plante, mayor of Montreal, Canada, last week stated “the ULEZ scheme has shown its efficiency to reduce air pollution. In fact, many cities across the world are already looking at the ULEZ in London and getting inspiration to elaborate similar schemes”.

What next for Clean Air Zones?

Green and other measures aimed at reducing carbon levels and thus improving air quality are significant and necessary if the UK is to achieve its low carbon targets (net zero by 2050).  It also remains the case that air quality levels in certain discreet areas of our cities may be unlawful and need to be addressed. Failure to do so leaves local and central government exposed to potential challenge from environmental groups such as Client Earth. There may also be the potential for claims from individuals whose health is affected. Despite the motoring lobby, public opinion at large has shifted in recent years so as to be more open and supportive of green initiatives  -  Clean Air Zones are here and will continue to be part of the solution.