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EU Urban Mobility Observatory
News article4 November 20191 min read

London’s ULEZ cuts NO2 pollution by a third

Since its introduction in April 2019, London’s Ultra-Low Emission Zone (ULEZ) has cut nitrogen dioxide (NO2) pollution by a third. Quarterly averages from roadside monitors in the UK capital show that levels have fallen by 36% in six months, from 89µg/m3 (January to March) to 57 µg/m3 (July to September).

report on the zone’s first six months, published by London's City Hall, highlights some more encouraging results in terms of reducing air pollution, namely:

  • 13,500 fewer polluting cars being driven into Central London daily;
  • 77% of vehicles in the zone meeting ULEZ emission standards (compared to 61% in March 2019 and only 39% in February 2017);
  • A 3-9% decrease in traffic flows in Central London in May and September 2019. This highlights the wider ULEZ benefit of encouraging people to change their transport mode, i.e. to walk, cycle or use public transport, instead of taking the car;
  • Levels of fine particulate matter (PM2.5) have reduced slightly, although reducing these emissions is more challenging as over 50% of London’s PM2.5 emissions blow into the capital from outside sources.

Sadiq Khan, the Mayor of London, stated: ‘These figures prove without a doubt that ULEZ is exceeding expectations, reducing polluting vehicles and cleaning up our lethal air. I am determined to stop Londoners breathing air so filthy it is damaging our children’s lungs and causing thousands of premature deaths. The ULEZ shows what we can achieve if we are brave enough to implement such ambitious policies.’

Earlier in October, Mr Khan joined over 30 other global mayors to commit to reduce PM2.5 pollution in line with World Health Organisation (WHO) guidelines by 2030. He said, ‘I now hope the government will match my ambition and amend their environment bill to ensure it has the legally binding WHO recommended limits to be achieved by 2030 that we need to protect public health.’

If re-elected next year, the Mayor plans to extend the ULEZ boundary in 2021. In comparison, rival Mayoral candidate Shaun Bailey has stated previously that he would use the funds that have been put aside for the planned expansion to pay for 371 electric buses instead.

Transport for London’s Catherine Westoby will be presenting the findings on the ULEZ’s first six months at Air Quality News’ sixth National Air Quality Conference in the UK (click here) for more information).



Publication date
4 November 2019
  • Urban Vehicle Access Regulations
  • United Kingdom