World Half Full
Low-emission zones improving air quality
Clean-air or low-emission zones (LEZ) are being rolled out in more UK cities, with London’s mayor proposing to extend its ultra-LEZ to the suburbs. LEZs are designed to get cities to reach their legal limits for air pollution sooner and to reduce the health burden from breathing poorer air.
Many cities across the UK and Europe failed to meet legal limits for air pollution that were set in 1999 and that were supposed to have been met by 2010. This is largely because vehicles that were designed to pass official exhaust tests ended up producing much more air pollution when actually driven on the road. (There is strong evidence air pollution still causes harm at concentrations well below those legal limits.)
Enter the LEZ, which has at least restricted the most polluting vehicles: those that are old, and especially diesels. Evidence from London’s schemes and the hundreds operating Europe reveal a number of other pluses.
In 2010, the health benefits from lower air pollution in LEZs in 25 German cities were estimated to be between €760 million and €2.6 billion.
In 2008, London’s first LEZs led to improvements in particulate pollution from traffic along busy suburban roads. Tightening the zone in 2012 saw further improvements, compared with areas outside the capital, but progress became slow and patchy, leading to a projection that it would take London another 193 years to comply with legal limits.
So six years ago, London established the ultra-LEZ, or Ulez, for the city’s centre. By October 2022 it had reduced nitrogen dioxide from traffic by 46%; the benefit across inner London was 21%.
Perhaps surprisingly, air pollution doesn’t get worse outside the zone as a result of diverting vehicles. Instead the experience from London and cities in Germany show the cleaner vehicles are also used in the surrounding area, spreading the benefit. The Ulez also induced accelerated air pollution improvements on the boundary roads.
There are some significant fines for drivers of non-compliant vehicles found in an LEZ. In Scotland the fine is £60 per day; in France it’s €68. Schemes in England allow non-compliant vehicles to enter for a charge: £9 per day for a car in Bristol and £12.50 in London. This has led to accusations the schemes are a cash cow, however, low- and ultra-low emission charges made up just 6% of Transport for London’s income in 2021-2022. All proceeds must be spent on local transport projects.
Health-wise, poorer communities have the most to gain. They experience worse air pollution than their richer counterparts. More air pollution is produced per square kilometre in the poorest areas but, when it comes to driving, the poorest contribute least to the problem. Many poorer households don’t own cars and those that do drive less than wealthier people. In 2010, the cars owned in the poorest 10% of the UK travelled just 40% of the distance of those owned by the wealthiest.
Many zones have grants to help people upgrade their old vehicles. Londoners can apply for up to £2,000 for a car, £5,000 for wheelchair-accessible vehicles and £9,000 for small-business vans.
The UK government funds a scheme for zones outside London but help is available only in specific areas. The charity Asthma and Lung UK has called on the government to fund a national scheme to help poorer households and those with long-term health and mobility problems upgrade to cleaner ways of travel.
Some of the highest exposures to carcinogenic diesel exhaust occur when people travel along busy roads. A study of drivers in London found the greatest exposures to diesel exhaust among taxi drivers, couriers and garbage truck drivers. A study of more than 200 London schoolchildren found greater exposures among those who were driven to school and those who walked along main roads, compared with pupils who walked to school on quiet roads.
While clean air zones, low- and ultra-low emission schemes are a way to improve air pollution locally for all communities, broader improvements are achievable. For example, the Parisian LEZ has not only helped reduce air pollution but in conjunction with other policies has encouraged different modes of travel, further extending benefits for public health.