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Millions of Londoners to Breathe Cleaner Air if ULEZ Expanded London-Wide

  • City Hall data reveals all of outer London’s monitoring stations are currently exceeding the new WHO recommended guideline for harmful NO2
  • Five million Londoners are expected to breathe cleaner air if ULEZ is expanded London-wide
  • Of these, 340,000 people in outer London would, for the first time, live in areas meeting interim WHO targets for nitrogen dioxide
  • First 10 community groups receive their Breathe London air quality sensors enabling them to monitor pollution locally

Five million people are expected to breathe cleaner air if ULEZ is expanded to outer London. The expansion would reduce the number of Londoners living in areas exceeding interim Word Health Organization (WHO) targets for nitrogen dioxide (NO2) by 13 percent. This would improve air quality for 340,000 people including 87,000 children, 50,000 older people and 145 schools.

Around 4,000 Londoners died prematurely in 2019 because of long term exposure to air pollution, children can have permanently stunted lungs with adults suffering a range of illnesses from asthma to lung disease to heart disease. Travelling around the capital is a major source of exposure to poor air quality, with road vehicles causing nearly 50 per cent of the city’s air pollution. Now the latest City Hall analysis has revealed the stark situation in outer London which at the moment isn’t in the Ultra Low Emission Zone.


  • All of outer London’s monitoring stations are exceeding the new WHO recommended guideline for harmful pollutant NO2of 10 ug/m3.
  • 80 per cent of outer London’s monitoring stations are currently showing concentrations above the interim WHO recommended guideline for NO2 of 20ug/m3.

New research by COMEAP, the Government’s independent advisory group on air pollution and health, has also shown the impact of air pollution on dementia, adding to the ever-growing body of evidence of the serious health impacts of pollution at all stages of life.*  60,000 of the 210,000 new dementia cases each year are already thought to be linked to toxic air. If no further action is taken to reduce air pollution, around 550,000 Londoners will develop diseases related to poor air quality over the next 30 years. In this case the cost to the NHS and social care system in London is estimated to be £10.4 billion by 2050.

The urgent need to tackle the capital’s toxic air and protect all Londoners’ health is why the Mayor is consulting on expanding the ULEZ London-wide. Transport for London’s consultation closes today and Londoners can give their views on the expansion at

Last week the Mayor published findings from the first six months of the ULEZ expansion to the North and South Circular roads, which showed significant progress in cleaning up London’s air. There were 67,000 fewer non-compliant vehicles in the zone on an average day compared to the period right before the ULEZ expanded. As a result, the scheme has helped reduce roadside nitrogen dioxide (NO2) levels in inner London by 20 per cent compared to a scenario without the ULEZ and its expansion to inner London.

The central London ULEZ helped reduced NO2 concentrations by 44% in the zone, particulate matter concentrations (PM2.5) by 27% and carbon emissions by 6%.

The Mayor and Bloomberg Philanthropies have also announced today the first community groups to receive free Breathe London air quality sensors, empowering them, for the first time, to make their own choices about where they monitor local air pollution.

The free sensors monitor levels of pollution, including particulates (PM2.5) and nitrogen dioxide (NO2) both of which are harmful to health and are providing Londoners with even more hyperlocal air pollution data.

The £1.5m investment for the Breathe London network – £790,000 from City Hall and £720,000 from Bloomberg Philanthropies – is funding more than 200 air quality sensors across the capital, as well as further research and community engagement. Managed by experts from the Environmental Research Group at Imperial College London through Imperial Projects, the wider Breathe London Network currently stands at more than 300 sensors across London and continues to grow as businesses and other organisations can buy into the network and purchase their own air quality sensors.

Mums for Lungs in Redbridge is one of the first 10 community groups to be awarded a free Breathe London sensor, which is located in Elmhurst Gardens, an urban park and playground. Elmhurst Gardens sits outside the expanded ULEZ and residents will be monitoring the pollution that predominantly comes from the North Circular.  The Mayor visited the park today to meet residents and find out more about the impacts of air pollution in this outer London community.

Mayor of London, Sadiq Khan said: 

“The health of Londoners across the capital is being damaged by air pollution and I’m doing all I can to improve it. This data shows how important it is to take bold action that benefits all Londoners. If the zone is expanded, five million people living in the outer boroughs would also be able to breathe cleaner, less polluted air and this is why I’ve been consulting on expanding the ULEZ London-wide. Deadly air pollution contributes to children developing stunted lungs, asthma and a whole host of other health issues and new research has shown that it also puts people at increased risk of developing dementia. We need to act now to protect the most vulnerable from the worst consequences of toxic air and build a safer, fairer, greener and more prosperous city for everyone.”

Michael R. Bloomberg, UN Secretary-General’s Special Envoy for Climate Ambition and Solutions and founder of Bloomberg LP and Bloomberg Philanthropies, said:

“London’s air is getting cleaner, thanks largely to Mayor Sadiq Khan’s strong leadership, but air pollution continues to harm the health of residents, with low-income neighbourhoods suffering the most. Bloomberg Philanthropies has been glad to support Mayor Sadiq Khan’s energetic and effective efforts on this issue, and these new sensors – which will collect local data on air quality across London – will empower community groups to clean the air and help them lead longer and healthier lives.”

Lydia Fraser-Ward – Mums for Lungs, Redbridge said:

“We are delighted to have been awarded an air quality sensor by the Mayor of London and Breathe London Community Programme. Our community in South Woodford in the London Borough of Redbridge are deeply concerned about the levels of air pollution in the neighbourhood, particularly in the playground of our lovely local park Elmhurst Gardens which sits next to the North Circular. It is thanks to this project that we now have reliable and up-to-date data which members of the public can access online. This data demonstrates when pollution levels are at their highest and acts as important evidence to lobby for mitigation measures to help to protect park users from exposure to dangerously high levels of nitrogen dioxide and particulate matter in the future.”

Andrew Grieve, an air pollution scientist from Imperial’s Environmental Research Group ’ who installed the sensors said:

“Putting the power of air quality monitoring into communities’ hands is a game-changer.   Working with our first ten community groups has been a privilege. Each has a unique perspective on air pollution and seeing their passion, energy and commitment to improving their local environment shows just how powerful grassroots community monitoring can be.”

Head of Air Quality Measurement, Iq Mead, whose team at Imperial also monitor and analyse the data, added:

“Air pollution is the largest environmental risk to health in the UK and globally, with 7 million premature deaths attributed to exposure to poor air quality by the World Health Organisation each year. It’s great to see communities like these step up and make a difference.”

The latest City Hall analysis reveals all of outer London’s monitoring stations are exceeding the new WHO recommended guideline for NO2 of 10 ug/m3

80% of outer London’s monitoring stations are currently showing concentrations above the interim WHO recommended guideline for NO2 of 20ug/m3.

Air quality is expected to improve across outer London should the ULEZ be expanded London-wide, benefiting the approximately 5 million people living there. Expanding the ULEZ London-wide will ensure nearly 340,000 additional Londoners in outer London would no longer live in areas exceeding the WHO interim target of 20 ug/m3 which is much tighter than the legal limit, a reduction of 13%. This includes:

  • an extra 87,000 children in outer London would no longer live in areas exceeding the 20ug/m3 interim WHO guideline, a reduction of 13%.
  • With shocking new evidence about the impact of air pollution on dementia, expanding the ULEZ London-wide would ensure 50,000 more people over the age of 65 no longer live in areas exceeding the 20ug/m3 interim WHO guideline. This is a reduction of 14% in outer London.
  • It is estimated that, with the ULEZ expanded London-wide, 145 schools, most of them in outer London, would also meet the tighter WHO interim target of 20 µg/m3 NO2.

COMEAP reviewed nearly 70 studies in human populations which looked at possible links between air pollution and a decline in mental ability and dementia in older people. You can read its report here.

The first 10 community groups to receive free Breathe London sensors are:

  • Croydon Climate Action; Croydon
  • Earls Court Society; Kensington and Chelsea
  • Harlesden Neighbourhood Forum; Brent
  • Healthy Streets North Tottenham; Haringey
  • Rectory Road Residents Association; Hackney
  • Shadwell Responds; Tower Hamlets
  • Mums for Lungs Redbridge; Redbridge
  • Clean Air Bayswater; Westminster
  • Barking Food Forest; Barking and Dagenham
  • Victoria Park Harriers & Tower Hamlets Athletics Club; Tower Hamlets

About Breathe London:

Following a pilot generously supported by the Children’s Investment Fund Foundation and Clean Air Fund, the Mayor and Bloomberg Philanthropies are investing in a combined 202 air quality sensors prioritising schools, hospitals and locations chosen by community groups, along with cultural institutions and museums. The sensor network, data analysis and website are managed through Imperial Project by scientists from the Environmental Research Group at Imperial College London’s School of Public Health.

The Breathe London Community Programme gives local community groups and Londoners the opportunity to apply for free air quality sensors. It is aimed at vulnerable communities and areas that have poor air quality, limited green space or high deprivation.

Community groups were invited to apply for the first 10 of 60 free sensors in October 2021.Those selected met the criteria defined by an independent advisory panel of experts from the air pollution and health sectors, as well as charities and community groups.

Each of the successful community groups has pledged to measure air pollution, raise awareness or make interventions within their own local community.

Applications for the next 30 free sensors available under the Community Programme will open in autumn 2022.

Real-time, user-friendly air quality data is available on the Breathe London website.

About Imperial College London and the Environmental Research Group:

Imperial College London is one of the world’s leading universities. The College’s 20,000 students and 8,000 staff are working to solve the biggest challenges in science, medicine, engineering and business.  Imperial is University of the Year 2022 in the Times and Sunday Times Good University Guide. It is the world’s fifth most international university, according to Times Higher Education, with academic ties to more than 150 countries. Reuters named the College as the UK’s most innovative university because of its exceptional entrepreneurial culture and ties to industry.  Imperial has a greater proportion of world-leading research than any other UK university, according to the Research Excellence Framework (REF). Imperial ranks first in the UK for research outputs, first in the UK for research environment, and first for research impact among Russell Group universities.

The Environmental Research Group is part of Imperial’s School of Public Health and is a leading provider of air quality information and research in the UK, combining air pollution science, toxicology and epidemiology to determine the impacts of air pollution on health and the role specific pollutants play in causing disease and deaths. They work closely with those responsible for air quality management supporting policies and actions to minimise the impact of air pollution on health and established the London Air Quality Network – and Breathe London Programme – which continuously monitors air pollution levels at sites across London.

About Bloomberg Philanthropies’ Global Clean Air Program:

Bloomberg Philanthropies leads the world’s most ambitious clean air effort that aims to improve air quality through support for pilot projects in cities, as well as partnerships with national governments and organizations. This includes initiatives in Brussels, Jakarta, London, Milan, Paris, Warsaw, and other governments around the world.

About Bloomberg Philanthropies:

Bloomberg Philanthropies invests in 941 cities and 173 countries around the world to ensure better, longer lives for the greatest number of people. The organization focuses on five key areas for creating lasting change: the Arts, Education, Environment, Government Innovation, and Public Health. Bloomberg Philanthropies encompasses all of Michael R. Bloomberg’s giving, including his foundation, corporate, and personal philanthropy as well as Bloomberg Associates, a pro bono consultancy that works in cities around the world. In 2021, Bloomberg Philanthropies distributed $1.66 billion. For more information, please visit or follow us on FacebookInstagramYouTubeTwitter, and LinkedIn.

Media Contact:

Marshall Cohen
Bloomberg Philanthropies