By Richard Smith, Chair UK Health Alliance on Climate Change

As I cycle along London’s South circular road from Clapham to Forest Hill to hear a speech by Sadiq Khan, London’s mayor, I reflect that this is the road that contributed to the death of Ella Adoo-Kissi-Debrah. As her mother, Rosamond (who attended Khan’s speech), says: “In the inquest into my daughter’s death the coroner was very clear that the pollution on the South circular is what started Ella’s asthma and ultimately contributed to her death.” The South circular is a narrow, busy, congested, and filthy road.

Air pollution, says the World Health Organisation, kills some seven million people a year, 4000 of them in London. When Khan became the London mayor in 2016, he made reducing air pollution a priority. There have been improvements, but a study last month showed that every hospital, medical centre, and care home in the city is located in areas that breach the new updated WHO guidelines for nitrogen dioxide and particulate matter.

Road transport accounts for about half of London’s air pollution, and in February 2008 the city introduced a Low Emission Zone (LEZ) in the centre. Heavy goods vehicles over 12 tonnes had to pay a charge to drive in the centre, and in July 2008 the charge was extended to include heavy goods vehicles over 3.5 tonnes, buses, and coaches. The scheme was extended further in January 2012, and between 2008 and 2013 the LEZ contributed directly to a 20% reduction in PM10 emissions and indirectly to a 27% per cent reduction in PM2.5 emissions and a 25% reduction in nitrous oxide emissions.

In April 2019 an Ultra Low Emission Zone (ULEZ) was introduced in Central London and expanded to (but not including) the North and South circular roads on 25 October 2021. Vehicles that don’t meet the standard must pay £12.50 a day to drive within the zone. A preliminary study of the effect of ULEZ in central London by Imperial College found an average reduction of less than 3% for nitrogen dioxide concentrations, and insignificant effects on ozone and particulate matter. https://www.imperial.ac.uk/news/231894/london-pollution-improved-with-evidence-small/#:~:text=They%20found%20that%2C%20compared%20to,on%20ozone%20and%20particulate%20matter%20 The researchers concluded that ULEZ is “not a silver bullet and that sustained improvements in air pollution require multiple measures.”

Khan is concerned not only with air pollution but also the climate crisis, with London committing to be net zero by 2030, and traffic congestion, which he said costs London $5 billion a year and means that the average driver in London spends six days a year stuck in traffic.

Trying to achieve his ambition of all Londoners being able to breathe clean air, Khan recognises that the best answer would be smart road user charging. But that is some way off, and he asked Transport for London to come up with options for reducing pollution from road transport. They presented three options: a Greater London boundary charge; a low-level daily Clean Air Charge for all but the cleanest vehicles; or extending the ULEZ to cover the whole of Greater London.

Conscious of the rising cost of living, Kahn wanted an option that would not be unaffordable for poorer Londoners but would have the biggest effect. After analysis of all the research he’s opted for extending the ULEZ to cover all of Greater London in 2023. This explains why he chose Forest Hill School to make his announcement—as the school is just outside the South circular. There will have to be consultation on the proposal, and Khan conceded that it will be politically controversial.

“Early assessments” suggest that making the ULEZ London wide will:

  • Reduce nitrous oxide emissions from cars and vans by between 285 and 330 tonnes
  • Lead to a reduction of around 10% in nitrous oxide emissions from cars and vans in outer London on top of building on the 30% reduction in road transport nitrous oxide emissions expected from the expanded ULEZ and tighter LEZ standards
  • Reduce CO2 emissions in outer London by between 135,000 to 150,000 tonnes
  • Reduce the number of the most polluting cars on London’s roads by between an additional 20 000 and 40 000 a day.

Khan emphasized that in addition to extending the ULEZ he is working to increase walking, cycling, and the use of public transport. The mayor’s office recently reported that more than a third of car trips made by Londoners could be walked in under 25 minutes and two thirds could be cycled in under 20 minutes.

Ending his speech on an upbeat note, Khan boasted that London is progressive and a “doer not a delayer” and hoped that London’s actions would inspire other cities.

As I cycled home along the South circular I wondered if I would live long enough to cycle along a less busy, less congested, and cleaner version of the road.

Competing interests: RS lives within the ULEZ, but the car he shares with his wife is a Fiat 500, meaning that there is no payment to drive within the ULEZ. He drove less than 30 miles in 2021 and has yet to drive at all in 2022.