The Mayor of London has presented new evidence indicating that air quality has improved across London following the first year of the expanded Ultra Low Emission Zone (ULEZ).
The initiative, aimed at reducing vehicle emissions, has contributed to significant reductions in pollutants such as nitrogen dioxide (NO2) and particulate matter (PM2.5).
Key Findings from the City Hall Report
The City Hall report indicates that:
- Roadside NO2 levels across London have fallen by 27% due to the ULEZ expansion
- PM2.5 emissions from vehicle exhausts in outer London were 31% lower in 2024 than they would have been without the expansion
- NOx (nitrogen oxides) emissions from cars and vans in outer London decreased by an estimated 14%
- The largest NO2 reductions were recorded in central London (54%), with inner London seeing a 29% reduction and outer London a 24% reduction
- The boroughs with the most significant reductions in NOx emissions include Sutton, Merton, Croydon, Harrow, and Bromley, where emissions were estimated to be 15% lower than expected without the expansion
- Cumulatively, NOx emissions from road transport across London were estimated to be 36% lower in 2024, equating to approximately 3,400 tonnes of emissions saved.
These results contribute to several health and environmental benefits. Air pollution has been linked to approximately 4,000 premature deaths annually in London, with exposure to pollutants such as NO2 and PM2.5 increasing the risk of respiratory diseases, cardiovascular conditions, and other health issues.
The report suggests that deprived communities, particularly those near busy roads, have benefited significantly. In outer London, an estimated 82% reduction in exposure to illegal pollution levels was recorded in 2023 compared to a scenario without ULEZ.
Meanwhile, since 2019, the cumulative reduction in carbon emissions due to ULEZ is equivalent to nearly three million one-way passenger trips between Heathrow and New York.
ULEZ Compliance
In terms of compliance, the report reveals:
- ULEZ compliance among vehicles has continued to improve, with 96.7% of vehicles seen in London meeting the standards in 2024, up from 91.6% in June 2023 and just 39% in February 2017
- Van compliance in outer London has surpassed 90% for the first time
- Nearly 100,000 fewer non-compliant vehicles were detected on an average day in September 2024 compared to June 2023, a 58% reduction
The Mayor’s scrappage scheme, which allocated around 200 million GBP to assist Londoners in switching to cleaner vehicles, has played a role in reducing older, more polluting vehicles on the road. More than 54,700 applications were approved before the scheme closed in September 2024, including over 400 vehicles donated to humanitarian and medical efforts in Ukraine.
Economic and Social Impact
Independent analysis indicates that the ULEZ expansion has not negatively impacted footfall or spending in retail and leisure sectors.
Visitor footfall in outer London increased by almost 2% in the year following the expansion.
Future Measures
London’s air quality is improving at a faster rate than the rest of England, particularly in outer London. The Mayor’s office and Transport for London (TfL) continue to implement additional measures, including introducing more zero-emission buses, to further improve air quality. As of 2024, 1,900 zero-emission buses operate in London, supporting the city’s broader efforts to reduce transport-related pollution.
While progress has been made, authorities acknowledge that further action is required to sustain improvements in air quality and public health. The ULEZ expansion remains a central part of London’s strategy to tackle air pollution and mitigate its long-term effects on residents.
The full report is available here.
