The London boroughs that have benefited most from the expansion of Sadiq Khan’s Ulez ultra-low emission zone can be revealed.
The zone expanded from inner London to the Greater London boundary on August 29, 2023, in what mayor Sir Sadiq hoped would result in cleaner air for five million Londoners.
Transport for London has now published data for the first year of the expansion, comparing the amount of pollution recorded with estimates of what the levels would have been like had the Ulez not been extended beyond the inner boundaries of the North and South Circular roads.
Eleven boroughs each had the same cumulative benefit in reduced emissions, when falls in nitrogen oxides, carbon dioxide and PM2.5 particulates were estimated for 2024.
These boroughs were: Barking and Dagenham, Bexley, Bromley, Croydon, Enfield, Harrow, Havering, Hillingdon, Kingston, Merton and Sutton.
These boroughs each saw a 15 per cent reduction in NOx, a 32 per cent reduction in PM2.5s and a one per cent reduction in CO2.
The Tory boroughs of Bexley, Bromley, Harrow and Hillingdon had joined Surrey County Council in mounting a legal challenge to the Ulez expansion, but were defeated at the High Court.
The reduction in NOx being emitted from vehicle exhausts resulted in an average reduction in nitrogen dioxide (NO2) of 4.8 per cent across the outer London extension zone.
Across London, NO2 concentrations were 27 per cent lower compared with a scenario without any phases of the Ulez.
Announcing his plans to take the Ulez Londonwide, Sir Sadiq said in 2022 that it would tackle the “triple challenges of air pollution, climate change and congestion”.
The year-on report found there had been a one per cent reduction in CO2 emissions in outer London, and two per cent reduction in CO2 across all of London when including the effects of all three phases of the Ulez.
The primary aim of the Ulez was to reduce NO2, but it has also reduced PM2.5 levels.
NO2 is a toxic gas that exacerbates asthma, impedes lung development, and raises the risk of lung cancer.
The mayor has commissioned comprehensive analysis to determine how and when London can meet the World Health Organisation guidelines on NO2 and PM2.5s. The report will be published later in 2025.
Sir Sadiq said he had “no plans” to change the Ulez vehicle emission rules, despite calls for campaigners to go further and target diesel vehicles.
He has warned that a third runway at Heathrow airport would wipe out the environmental gains from the Ulez.
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