The expansion of the ultra-low emission zone to the edge of the North and South Circular roads resulted in an astonishing 60 per cent reduction in the number of non-compliant vehicles being driven in inner London.
This included a 63 per cent reduction in the number of “dirty” diesel cars – those which break the Ulez rules and would have to pay the £12.50-a-day levy.
Their number reduced from 79,000 to 29,000 a day in the 12 months after the Ulez was expanded to the suburbs in October 2021.
Mayor Sadiq Khan said the findings delivered a “game, set and match” boost to extend the Ulez to the Greater London boundary on August 29.
He told the Standard: “As a former lawyer, I just love looking at the evidence. The evidence today is game, set and match unequivocal. The Ulez is the most effective policy to clean up the air in our city there has ever been.
“The results are remarkable. There is no other policy anywhere which is seeing these sorts of improvements to air quality and reductions in nitrogen oxides, nitrogen dioxides and PM particulates.
“We have now got 60 per cent fewer of the most polluting vehicles in inner London. Why shouldn’t the whole of Greater London also be able to breathe cleaner air?”
A report by Transport for London, analysing the impact of the first year of the Ulez expansion, said the “significant” fall in the dirtiest diesels was a “key metric of success for the policy in removing harmful emissions from the city”.
But the 96-page report also revealed that levels of nitrogen dioxide (NO2) in central London – the same area as the congestion charge zone, covering the West End and City of London financial district – had risen since the Ulez was expanded.
The Ulez was credited with reducing NO2 levels in central London by 56 per cent in central London and 22 per cent in inner London between October and December 2021.
But by October last year, this had fallen to 46 per cent and 21 per cent – a finding likely to be seized upon by opponents of expanding the Ulez for a second time to the Greater London boundary.
Mr Khan said that while the percentage reductions achieved in the suburbs might be smaller, the total reduction in toxic emissions was still sizeable because it was over a far wider area.
The report said: “Central London roadside concentrations have risen slightly since the end of the pandemic as traffic returns to central London. As the concentrations have risen the Ulez impact has therefore reduced.”
But it said NO2 remained below pre-pandemic levels – showing the Ulez’s “sustained and positive impacts on pollution” by encouraging drivers to switch to cleaner vehicles.
The Ulez expansion to the inner boundaries of the North and South Circulars increased the zone’s size by 18 times and means it now covers four million Londoners.
Mayor Sadiq Khan has decided to extend the zone across all 33 boroughs on August 29, which he says will deliver cleaner air for five million more Londoners.
The first-year report said 94.4 per cent of vehicles driving within the current zone complied with the rules and did not have to pay the levy.
Prior to the zone’s widening, only 86.9 per cent of vehicles met the exhaust emission standards.
The total number of vehicles seen within the zone on an average day has fallen by 4.9 per cent, from 950,000 to 903,000.
Of these, the number of non-compliant vehicles has reduced from 124,000 to 50,000 – a drop of 74,000, or 59.7 per cent.
But this means TfL is raising less cash – about £400,000 a day. More than a quarter of non-compliant vehicles are exempt from paying the levy or the £180 penalty fines.
The Ulez has encouraged motorists to switch to cleaner vehicles – there has been a 3.1 per cent increase in compliant vehicles, up from 826,000 to 852,000.
Mr Khan said: “The evidence from this landmark report is clear – the Ulez works. This is beyond dispute.
“With the majority of deaths attributable to air pollution in outer London, it’s vital that we expand the Ulez London-wide.”
But Nick Rogers, City Hall Conservatives transport spokesperson, said: “Sadiq Khan’s Ulez expansion will have a negligible effect on air quality in outer London, while hitting low income and vulnerable families hardest.
“Sadiq Khan needs to listen to Londoners, scrap his expansion, and spend the money on policies that actually reduce air pollution.”
The report also reveals the biggest cut in emissions has been seen in the bus fleet – which is not subject to the Ulez rules.
There has been a 75 per cent reduction in NO2 emissions from London buses since 2019, following the retro-fitting of cleaner engines and replacement of old vehicles with electric buses.
Emissions of microscopic PM2.5 particulates are estimated to have reduced by 19 per cent across the Ulez area since the central London zone was introduced in April 2019. Carbon dioxide is down four per cent over the same period.
Traffic levels were said to have “largely returned to pre-pandemic” levels in outer London but remain below 2019 levels in central and inner London – though central London is seeing the sharpest rise in traffic.
The report states: “Further expansion of the Ulez to outer London will help improve air quality for millions more Londoners.”
But it said it was “becoming increasingly complex to disentangle” the impact of Ulez on air pollution, as the “natural churn” of replacing older vehicles with newer ones, the arrival of cleaner buses and taxis, and clean air policies pursued by local councils were also factors.
TfL said there had been a “step change” in the number of cleaner vehicles on the capital’s roads.
Sarah Woolnough, chief executive at Asthma + Lung UK, said: “The Ulez expansion across inner London shows that where there is political leadership, things can get better and millions of people can breathe cleaner air.”
Jemima Hartshorn, founder of Mums for Lungs, said: “The Ulez is giving kids a breather – and we need more action to ensure that we can all be healthy in our capital.”
Dr Gary Fuller, air pollution scientist at Imperial College London, who reviewed TfL’s data, said: “The 10th anniversary of the death of Ella Kissi-Debrah is a powerful reminder of the impacts of air pollution on London’s children and young people; especially those living, travelling or at school close to major roads.
“The central London Ulez, and its extension to inner London, has bought about measurable and sustained improvements to air pollution from traffic.
“Many cities in the UK and around the world are looking to follow London’s lead. I hope that the evidence here will improve the design of similar schemes more widely.”
