The covid-19 pandemic has brought a renewed focus on both air quality and local transport. The virus’ particular effects on respiration mean the case for improvements in air quality has never been stronger. This is coupled with the experience of significantly cleaner air during lockdown, when traffic levels and associated pollution evaporated overnight, leading to calls for these lower levels of pollution to be maintained as lockdown eases.

Pre-pandemic, public transport was a natural focus for a drive to improvements in air quality, but as lockdown eases, challenges with social distancing and environments with a concentration of high touch locations such as handrails are still being treated with some caution, leading to a trend towards higher car use in the current phase as the economy re-opens.

An alternative is therefore needed and clean air zones (CAZs) feature high in the list of possibilities. At their most basic, a CAZ introduces a daily charge for certain vehicle classes entering or moving within a defined area. Legally, they are created under the Transport Act 2000 where powers are given to local traffic authorities to make a charging scheme. The act also allows for traffic authorities to act jointly, opening up the possibility of joined up CAZs covering one or more local authority areas within a conurbation.

The comparatively limited procedural requirements bely the complexity of a CAZ. Careful assessment and analysis are needed to ensure that the zone does not deter local economic activity but also incentivises improvements in the emissions of the worst polluting vehicles. For this reason, a CAZ is not a one size fits all solution, but a step requiring detail assessment and modelling.

A number of cities are already in the process of considering or implementing CAZs and there is much which can be said to recommend them. The revenue raised from the charge is ring fenced for local transport improvements and thus the upfront investment by a city of region can be offset in the longer term income stream.

The physical infrastructure required to implement a CAZ is not extensive. Signage and cameras are needed but there are no direct changes to road layouts or existing traffic management systems. More complex, however, are considerations such as setting the level of charges to push behaviour towards upgrading vehicles to less polluting models or reducing journey numbers. Local authorities also need to establish mechanisms for collection of the charges and an enforcement process.

Against this background, the government has recently announced that it will review the target for levels of PM2.5 (tiny particles produced by transport and industry) but the new targets will not be set until 2022. Environmental campaigners have criticised this lack of ambition and suggested that failure to include binding targets in the Environment Bill is a missed opportunity.

For local authorities grappling with the need to facilitate a Covid-safe return to ‘normal’ for the wider economic benefits, even in the absence of national air quality targets, the case for measures to improve air quality remains clear. The CBI has recently reported the results of a study which found that time off work through sickness or caring for sick children leads to the loss of up to £3m of working days annually. Improvements in air quality could therefore bring direct economic benefits.

It has been widely reported that measures such as the introduction of more cycle lanes and improvements to pedestrian safety better facilitate active transport and thus lower the risk of covid transmission. CAZs are another tool in local government’s arsenal to take steps to improve air quality.

One of the key challenges for local authorities in developing any scheme is getting their local communities on board. For some cities, because of a Direction from government, they have no choice but to tackle the issue and introduce measures to deal with air quality.

For others, the decision to consider a scheme may be to get ahead of the issue in a pro-active way. Whatever the reason, there are requirements to consult but the communications need to explain why a scheme is needed, the benefits it will bring and its impacts. There is no guarantee that a scheme will be popular, and councillors will be particularly attuned to this, but considering the communications needed right at the start will undoubtedly help.

It is also the case the central government are very likely to ‘pass the buck’ to local authorities to deal with air quality. They too know that designing an acceptable local scheme is challenging. The rhetoric will focus on the ability of local authorities to design a scheme that understands the needs of their area. The reality is that they do not want to impose schemes and risk electoral fallout.

So it is imperative to think of a CAZ, or other scheme, as having its own stand-alone reputation. This should involve a ‘brand’ for the scheme, effective and ongoing engagement with communities, listening to feedback, as well as regular stakeholder engagement.

Aside from the obvious health benefits of such scheme, local authorities can also use it to build their own reputations. At a time when the emphasis is on the country developing a more outward facing, global approach what could be better for an authority than being able to ‘sell’ the quality of its environment as a way of attracting businesses and inward investment?

Laura Thornton and Stuart Thomson are the legal director and head of public affairs respectively at BDB Pitmans.