Pollutionwatch: debunking myths about low-emission zones

theguardian.com:

Clean-air or low-emission zones are being rolled out in more UK cities, and the London mayor is proposing to extend the ultra-low emission zone to the suburbs.

These zones are designed to speed up the attainment of legal limits for air pollution and to lessen the health burden from breathing poor air. While not new, such zones can be controversial, especially when they are introduced or expanded.

Many cities across the UK and Europe have not met legal limits for air pollution that were set in 1999 and should have been reached by 2010.

This is largely due to vehicles that were designed to pass official exhaust tests but produced much more air pollution when actually driven on roads.

Low-emission zones therefore restrict the most polluting vehicles; those that are old, and especially those with diesel engines.

Evidence from London’s schemes and the hundreds that operate in Europe counter many of the myths around these schemes.

First, the zones work, if they are sufficiently ambitious. In 2010, the health benefits from less air pollution in zones in 25 German cities were estimated to be between €760m and €2.6bn.

In 2008, London’s first low-emission zones led to improvements in particle pollution from traffic along busy suburban roads.

Tightening the zone in 2012 created 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.

The ultra low emission zone, or Ulez, started in 2017 in central London. By October 2022 it had reduced nitrogen dioxide from traffic by 46%. The benefit across inner London was 21%.

Second, air pollution does not get worse outside the zone as a result of diverting vehicles.