New data shows Mayor’s ULEZ expansion is working better than expected, bringing cleaner air to five million more Londoners

• Data shows ULEZ expansion is working better than predicted, with London’s air quality continuing to improve at a faster rate than the rest of England and pollutant emissions in 2023 reducing dramatically, compared to a scenario without the London-wide expansion.  
• PM2.5 exhaust emissions from cars in outer London are estimated to be 22 per cent lower than without the expansion.
• Within the outer London ULEZ area, NOx emissions from cars and vans are estimated to be 13 and seven per cent lower than a scenario without the expansion. This is equivalent to removing 200,000 cars from the road for one year.*
• Overall, NO2 concentrations in outer London are estimated to be 21 per cent lower than without the ULEZ and its expansions.
• 96 per cent of vehicles seen driving in London as a whole are now compliant, with a 53 per cent reduction in non-compliant vehicles in only six months. 

New data from City Hall has revealed the expansion of the Ultra Low Emission Zone (ULEZ) across the whole capital last August is working - driving down emissions and bringing cleaner air to millions more Londoners.  

In London, around 4,000 premature deaths are attributed to toxic air each year as well as increased risks of asthma and cancer and emerging evidence of links between air pollution and dementia.**

The ULEZ is the centrepiece of a range of measures the Mayor is implementing to tackle London’s toxic air, including putting a record number of zero-emission buses on the roads. These additional measures are making a difference, but all the evidence shows that clean air zones like the ULEZ are the most effective tool available to quickly and meaningfully cut air pollution in big cities.  

Today’s report, which covers the first six months of the expansion across all London boroughs, shows that pollutant emissions in 2023 with the London-wide ULEZ expansion in place are dramatically lower, compared to a scenario without it: 

• Within the outer London ULEZ area, NOx emissions from cars and vans are estimated to be 13 per cent and seven per cent lower than a scenario without the expansion. This is equivalent to removing 200,000 cars from the road for one year.
• PM2.5 exhaust emissions from cars in outer London are estimated to be 22 per cent lower than without the expansion (six per cent more than expected).
• Across all measures, these impacts are aligned with, and in many cases greater than, what TfL estimated in the consultation for the outer London expansion.  

NO_X emissions savings in outer London now represent over 90 per cent of the total emission reductions seen in London as a result of the London-wide expansion. 

The report also shows that, compared to what roadside NO2 concentrations are estimated to have been in different parts of London without the ULEZ and its expansions: 

• Levels in Outer London are estimated to be 21 per cent lower  
• Levels in Central London are estimated to be 53 per cent lower  
• Levels in Inner London are estimated to be 24 per cent lower  

The report shows that London’s air quality at the roadside is continuing to improve at a faster rate than the average for the rest of England. In 2014, the gap in nitrogen dioxide (NO2) levels between London and the rest of England was 20 µg/m3, whereas now it is less than 5 µg/m3. The expansion brought five million more Londoners into the ULEZ, and today’s report shows that outer London - which has historically had worse air quality than the rest of England average – now has levels of pollution much closer to levels in the rest of the country. 

Even in the short six-month timeframe covered by the report, roadside NO2 concentrations in outer London have dropped by up to 4.4 per cent compared to what would have been expected without the London-wide expansion of the scheme. Given the size of outer London, every percent makes a huge difference.

Compliance levels have also increased further than expected, with 96.2 per cent of all vehicles subject to the ULEZ recorded driving in London now compliant, up from 90.9 per cent in June 2023.  This has been aided by the Mayor’s £210m scrappage scheme, launched in January 2023 to support Londoners to switch to cleaner vehicles, with 53,351 applications approved so far and over 300 donated to humanitarian and medical efforts in Ukraine.***

There are now fewer older, more polluting vehicles driving in London, with 90,000 fewer non-compliant vehicles detected on an average day in February 2024 compared to June 2023, representing a 53 per cent reduction in non-compliant vehicles in the first six months of operation. 

Today’s preliminary data reveals significant progress, with a further report expected in early 2025 which will examine the first full year of the London-wide ULEZ expansion. The one-year report will be supported by an independent advisory group of experts and provide an even more comprehensive analysis of the air quality and traffic impacts of the scheme.  

The Mayor of London, Sadiq Khan, said: “The decision to expand the ULEZ London-wide was a difficult one, but necessary to save lives, protect children’s lungs and help reduce the risk of Londoners developing asthma, dementia and a host of other health issues. Today’s report shows that the ULEZ is working even better than expected. The expansion to outer London is already having a significant effect – driving down levels of pollution, taking old polluting cars off our roads and bringing cleaner air to millions more Londoners.

“London’s air quality is improving at a faster rate than the rest of England, and 96 per cent of vehicles are now compliant, with tens of thousands of Londoners benefitting from our scrappage scheme. It's thanks to our bold policies, including ULEZ, that we are now set to get London’s air to within legal limits by 2025, 184 years earlier than previously projected. But there’s still more to do and I promise to continue taking bold action – including more to clean up out air and rivers – as we build a fairer, greener London for everyone.”

The compliance, emissions, and concentrations impacts of the London-wide ULEZ expansion are aligned with, and in some cases greater than, TfL estimates in the consultation for the outer London expansion.****

Christina Calderato, Director of Strategy at TfL, said: “London is leading the way in improving air quality, with today’s report showing that harmful NOx pollutants from cars are estimated to be 13 per cent lower than a scenario without the ULEZ. This, along with reductions from vans, amounts to a total reduction of 424 tonnes in NOx emissions. We know that toxic air is associated with increased risks of asthma, cancer and dementia, and that it disproportionately affects poorer Londoners, and those from Black, Asian and minority ethnic communities. With the greatest number of deaths attributable to air pollution occurring in outer London, it’s great to see these results since the ULEZ was introduced London-wide.”

Rosamund Adoo-Kissi-Debrah CBE said: “I am encouraged and pleased to see that the 6 month analysis shows that expanding the ULEZ to outer London has reduced air pollution. People’s health, particularly children’s, should always be prioritised by society, and I hope politicians and decision-makers will continue to clean up London’s air so that everyone, regardless of where they live in the city, can breathe clean, safe air.”

Dr Maria Neira, Director, Department of Environment, Climate Change and Health at the World Health Organization said: "Improving air quality through initiatives like the Ultra Low Emission Zone in London is crucial for protecting public health and reducing the burden of disease” said. Cleaner air leads to healthier communities, lower rates of respiratory and cardiovascular illnesses, and a better quality of life for all residents. The World Health Organization commends the efforts of cities like London in implementing measures to reduce emissions from vehicles and improve air quality, which ultimately contribute to a healthier and more sustainable urban environment."

Jane Burston, CEO of Clean Air Fund said: “We all deserve to breathe clean air. This encouraging new data shows that millions of people across London are already benefiting from the measures taken to reduce harmful pollutants, with lasting improvements to their health. These results should encourage other leaders to take action to improve air quality. Cities around the world can follow London's example and realise the huge health and economic advantages of ensuring their citizens are breathing cleaner air."

Larissa Lockwood, Director of Clean Air at Global Action Plan said: "We all deserve to breathe clean air, but every single London borough has air pollution levels that are dangerous for human health. Toxic air leads to around 4,000 deaths in London each year. It’s great to see the positive impact that the expansion of the Ultra Low Emission Zone (ULEZ) is already having on the quality of our capital’s air, especially in London’s outer boroughs which have the highest numbers of air pollution related deaths. The reductions in air pollution levels we are seeing as a result of the ULEZ expansion demonstrate that our air pollution crisis is solvable, and we encourage all political leaders to take ambitious action to clean up our air for generations to come."

Tim Dexter, Clean Air Lead at Asthma + Lung UK said: "These results are an incredible win in the fight to clean up London’s air. It is great to see the continued impact that the ULEZ expansion is having on reducing pollution levels in the capital, with 97% of cars now compliant with the regulations across the city. This is perfect proof that clean air schemes really do encourage people to adopt cleaner modes of transport. Since the ULEZ expanded, five million more people in Greater London have had the chance to breathe cleaner air.

“Air pollution affects us all, but is particularly dangerous for the one in five of us with a lung condition, as it not only causes breathlessness, coughing and wheezing, but can result in life-threatening asthma attacks. The expansion of the ULEZ has been particularly significant for the 585,000 Londoners living with asthma and chronic obstructive pulmonary disease (COPD), as 60% of those affected have now been brought into the zone. In the UK, up to 43,000 early deaths a year are linked to toxic air. With the success of ULEZ so evident in London, we need to see similar bold action taken to clean up the air across the country."  

Professor Kevin Fenton, London Regional Director of Public Health, Office for Health Improvement and Disparities said: “Today’s report - looking at the impact of the first six months since the expansion of the ULEZ - provides welcome and reassuring news that action to clean up London’s air is working. All Londoners live in areas exceeding the latest health-based WHO guidelines for air pollution. Over 480,000 Londoners have a diagnosis of asthma and are more vulnerable to the impacts of air pollution, with more than half of these people living in outer London. This report shows that roadside NO2 concentrations in outer London are 21% lower than they would have been without all phases of the ULEZ. These important reductions are likely to have significant benefits for the health and wellbeing of Londoners especially our children and people living with asthma or other lung and heart disease. Our work here is not done, and strengthening our coordinated approach and work programmes will be crucial to maintaining this positive momentum and ensuring lasting improvements. Together, we can continue to make significant improvements in our city's air quality.”

Hirra Khan Adeogun, co-director of climate charity Possible, said: “Today’s ULEZ report shows that we really can clean up our air with simple, sensible public health policy that protects millions of Londoners from the harm of toxic air that literally shrinks childrens’ lungs and shortens the lives of residents. The ULEZ expansion has been so successful in cutting down air pollution in outer London that the reduction in Nitrogen Oxide  is as if we had removed an incredible  200,000 cars from the roads for a year. Sadiq Khan has shown real leadership here because without bold policies like the ULEZ, it would have taken nearly two centuries for London to meet legal air pollution limits; we’re now on track to hit  this milestone by 2025. Most Londoners support ULEZ and it is clear that the policy has done what it set out to do. It’s a win-win for clean air and for the climate. Cities around the world and across the UK should be looking at the example set in our capital. But we can’t stop here - there’s still so much more to do.”

Jemima Hartshorn, Founder & Director at Mums for Lungs, and Mum of two from Southwark: “This is really great news: schemes such as the London-wide ULEZ do really reduce air pollution significantly. Air pollution from road transport and especially diesel is a significant factor in the high asthma rates in children in London, as well as many other illnesses including cancer and cardiac issues. The ULEZ has been a great step towards cleaner air and healthier children, and we are so grateful for the Mayor's leadership. We look forward to the Mayor taking more action still, until London’s air no longer makes any children sick."

Cllr Kieron Williams, Leader of Southwark Council: "We welcomed the expansion of the ULEZ because we knew it would save live, so I am delighted to see it's worked so well, bringing cleaner air to Southwark residents and five million more Londoners. London's global leadership on this issue will mean children across my borough and our city living longer healthier lives. It's a huge achievement that we can all be proud of.”

Jaime Pumarejo, Executive Director of Breathe Cities: "The data from London’s expanded ULEZ shows the important role that clean air zones can play in improving the quality of the air that millions of people breathe. The success of the ULEZ is a testament to Mayor Khan’s dedication to tackling air pollution, both in London and on a global scale. Through the Breathe Cities initiative, London has provided a blueprint for other cities around the world to deliver cleaner air, tackle the climate crisis, and improve public health for generations to come.”

Mark Watts, Executive Director of C40: "This new data emphasises the success of London's ULEZ expansion, once again demonstrating how bold action to improve air quality can transform urban environments. Under Mayor Khan's leadership, five million more residents can enjoy cleaner air, placing London at the forefront of a global clean air revolution. At C40, we are proud to foster a network where cities can share best practices, drive collective action, and learn from one another. I am thrilled to share this data with the nearly 100 cities in our network, reinforcing this clarion call for cities worldwide to adopt and intensify efforts to combat air pollution."

Silviya Barrett, Director of Policy and Research at Campaign for Better Transport: “This report shows that the ULEZ extension is working, creating cleaner air for Londoners to breathe. To further improve the capital’s air quality, and reduce congestion, we now need to see fewer vehicles on the roads with ongoing investment in public transport and walking and cycling to help reduce the need to drive.” 

Muniya Barua, Deputy Chief Executive of BusinessLDN: “It’s very welcome to see new data released today showing the ULEZ is working. Not only is it making London’s air cleaner and saving lives, but it is also helping to make the city a more attractive place to live, work, and visit. With 96% of vehicles seen driving in outer London now ULEZ compliant, it’s positive to see that businesses and households are taking advantage of the Mayor’s scrappage scheme to switch to cleaner vehicles.”

Simon Birkett, Founder and Director of Clean Air in London: “Big low emission zones work well. Sharp reductions in emissions of oxides of nitrogen from vehicles and up to 4.4% in weather-adjusted concentrations nitrogen dioxide (“NO2”), a toxic gas, at roadsides are excellent early results from the ninth phase of low and ultra-low emission zones in London affecting the last group of vehicles in the last part of the city where roads spread out. Millions of people will benefit. Clean Air in London is pleased to support the Mayor’s world-leading action for cleaner air.”

Love Ssega, Founder of LIVE + BREATHE, : “As a community-led clean air movement, we are happy to see these results from the first six months of the ULEZ expansion, part of the Mayor of London's policies to tackle air pollution in London. At LIVE + BREATHE, we use art to get our message across, but we also want the facts and science to back it up. We hope that the health of Londoners, particularly young Londoners, can finally be taken seriously and for our voices to be heard as we resolutely say no to air pollution. “

Sophie O’Connell, senior policy adviser at Green Alliance: “Sadiq Khan has shown firm leadership on behalf of Londoners suffering the effects of dirty air – and there’s no question reducing traffic pollution will improve people’s health. When it comes to reducing carbon emissions, too, transport needs to shift gear the most of any part of the UK economy. Six months after expanding ULEZ, new evidence clearly shows it’s working: significantly reducing the number of the most polluting vehicles on the road, in and around London. That means Londoners are breathing cleaner air and contributing less to climate change today, and they’ll see the benefits for years to come.” 

Martin Machray, Executive Director of Performance at NHS England London: "This significant reduction in pollutants directly contributes to better health outcomes, reducing the risks of respiratory conditions such as asthma and lung cancer. The improvements in air quality are a critical step in protecting the health of Londoners, particularly the most vulnerable, and highlight the vital role of initiatives like the ULEZ in creating a healthier urban environment and reducing the burden on our health system."

Any net revenue raised through the ULEZ is reinvested back into public transport, including the expansion of bus services in outer London.  The ULEZ is expected not to raise any net revenue by the 2026/2027 financial year as the percentage of compliant vehicles continues to rise.     

ENDS 

*This is similar to the volume of NOx emissions that 200,000 cars would produce over one year, based on the NTS 2022 average mileage of 10,560 km per year.

**Health Burden of Air Pollution in London (Imperial College London): https://www.london.gov.uk/programmes-and-strategies/environment-and-climate-change/environment-publications/health-burden-air-pollution-london 

***scrappage figures up until 24 July 2024 - https://content.tfl.gov.uk/scrappage-scheme-factsheet-jul2024.pdf

***It is important to note that assumptions are always applied when modelling air quality impacts for future schemes. Assumptions made for the purpose of the consultation modelling were based on the best available information at the time. The impact analysis undertaken in the six month report is based on the up-to-date available information and assumptions since the scheme has been launched. Therefore, care must be taken when comparing the findings in the Six Month Report directly with the estimated impacts in consultation document.