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New network of sensors to tackle toxic air pollution across London

  • Mayor of London launches new partnership with Imperial College London and Bloomberg Philanthropies in fight against London’s toxic air
  • Funding for more than 100 air quality sensors to be installed at hospitals, schools and other priority locations to aidLondon’s green recovery from the coronavirus pandemic
  • Community groups, charities, businesses, individuals, academics and boroughs will also be able to “buy in” at a substantially reduced cost to the Breathe London network to source reliable air pollution data for local projects or schemes

Hospitals, schools and businesses across London will be able monitor levels of air pollution in their local area, as the Mayor of London, Sadiq Khan, launches a new network of sensors at key locations as part of his Breathe London air quality monitoring project.

Sadiq is funding more than 100 sensors to be installed at priority locations in the capital next year, enabling Londoners, businesses and community groups to see how polluted their local area is. For the first time, Londoners will also be able to “buy in” to the network at a low cost and host sensors in locations of their choice. This will revolutionise Londoners’ access to reliable data including for community groups, charities, businesses, individuals, academics and boroughs. Community groups and charities will be able to access the service at a discounted rate.

The new network will have a community focus and complement London’s existing, highest quality, reference grade monitors – most of which are owned and funded by London boroughs.

Allowing Londoners to “buy in” to the existing Breathe London network will significantly reduce the costs of sourcing reliable air pollution data for local projects or schemes like School Streets. In the past this has been prohibitively expensive, often leaving communities with no data, or worse – extremely inaccurate data with no quality control.

The new network will also support London’s green recovery from the coronavirus pandemic. As boroughs face challenging budget constraints, the new network will provide a low-cost option to supplement their reference monitoring, which is far more expensive to run. This will ensure that, despite budget cuts, boroughs are still able to increase the level of air pollution monitoring in their area.

The rollout of these new sensors, provided by global sensing and data analytics company Clarity Movement Co., is the next phase of the world-leading Breathe London project. Sadiq launched the scheme in January 2019, making it affordable to access reliable air quality data for the first time. The expert Breathe London team have experimented with different kinds of sensor technology, including mobile sensors fitted to Google Streetview Cars, wearable sensors monitoring children’s exposure to air pollution on their journey to school, a pilot project using lower-cost fixed sensors in a dense sensor network and evaluating the air quality impact of School Streets.

Following the successful pilot scheme, the Mayor has now committed to fund the programme for the next four years. Breathe London will be delivered through Imperial Projects by the Environmental Research Group, their first major project after moving to their new global centre of air pollution research at Imperial College London.

The project will focus on reaching communities that research shows have previously been less engaged with environmental programmes, including low-income and Black, Asian and Minority Ethnic groups. This part of the project will be supported by Bloomberg Philanthropies who also co-fund the Schools Streets evaluation programme.

The Mayor of London, Sadiq Khan said: “This is a major milestone for our world-leading Breathe London sensor network. Giving Londoners the opportunity to see the levels of pollution in their local area will improve awareness and help people reduce their exposure. It will also help City Hall, TfL and the boroughs better target efforts on improving air quality for all. As we face up to the current climate emergency, I hope the success of this scheme will act as a blueprint for cities around the world to battle their own toxic air emergencies.

“The onset of coronavirus – a vicious serious disease – has reminded us how important our work to clean up London’s toxic air is. It requires bold and innovative action and we can’t win this battle alone. This is why I have consistently demanded that the Government match my ambitions and improve the new Environment Bill to include legally binding WHO recommended limits to be achieved by 2030, and to give cities the powers and funding we need to consign air pollution to the history books once and for all.”

Professor Alice Gast, President of Imperial College London, said: “Air pollution is a grave threat to the health of all Londoners, with the most vulnerable communities often hardest hit. The Breathe London community sensor network will equip our city with the data it needs to drive change and protect Londoners at both a local and city-wide level. At Imperial we are determined to help improve London’s air through our science and our links with local communities. We are grateful to the Mayor of London and Bloomberg Philanthropies for their pivotal investment in this vital work.”

Michael R. Bloomberg, founder of Bloomberg LP and Bloomberg Philanthropies and 108th mayor of New York City said: “With more real-time data on local air quality, cities and communities can act quickly to cut pollution, protect public health, and grow the economy. London is already a global leader in using technology to better understand and address air pollution. At Bloomberg Philanthropies, we’re glad to expand our partnership with Mayor Khan – and showcase to more cities around the world a low-cost way to track pollution and improve their residents’ quality of life.”

Jemima Hartshorn, Founder of Mums for Lungs said: “This is a really great collaboration and we hope many schools will able to join this monitoring system at a low cost. We know that air pollution harms babies, children and in fact everyone’s health – from low birth weight to respiratory diseases, cancer and dementia – air pollution contributes to it all. Understanding local air quality will enable decision makers to prioritise action to reduce air pollution at hotspots. It will also help raise awareness of air pollution, which is critical for reducing it.”

Jane Burston, Executive Director of the Clean Air Fund, said: “We’re delighted to see the Breathe London project move into a second phase under new management from the GLA and the Environmental Research Group. What started two years ago as a global first in terms of the scale of trialling low-cost sensors has evolved into a world-leading air quality data management system, able to deliver new data and insights to inform clean air policy-making to the benefit of all Londoners.”

Elizabeth Fonseca, Air Quality Manager at Environmental Defense Fund Europe, said: “For two years, our team has mapped and measured pollution across London with innovative monitoring approaches, uncovering valuable insights about the city’s pollution while advancing the science. I’m excited the success of the pilot has enabled this next phase of Breathe London. We will soon launch a blueprint detailing what we learned here, with an aim to support global cities that are interested in using new air quality monitoring approaches to address air pollution and ultimately improve public health.”

Meiling Gao, Chief Operations Officer at Clarity said “London is a pioneering example to the global community on how to take immediate, achievable, and localised action against the global air pollution crisis, and we’re honoured to be a technology partner in this effort. The next phase of the Breathe London air quality monitoring project will not only empower London with data to better understand and respond to air pollution, but it will also serve as a blueprint for how governments worldwide can leverage affordable IoT technology to build healthier and more sustainable communities.”

Notes to editors

  • The state-of-the-art sensors weigh just 1.2kg and can be powered by a solar panel. They will measure nitrogen dioxide (NO2) and particulate matter (PM2.5) in London’s air. The team at Imperial have chosen to partner with the global sensing and data analytics company Clarity Movement Co. to provide the low-cost sensors.
  • These new monitors will not replace the need for continued support for the existing monitoring network managed by the boroughs, as only the reference monitors can be used for measuring compliance with legal pollution limits.
  • This announcement comes following the success of a two-year pilot phase. The pilot was funded by the Children’s Investment Fund Foundation and Clean Air Fund, and delivered by a consortium led by Environmental Defense Fund Europe with partners ACOEM Air Monitors, Cambridge Environmental Research Consultants, Google Earth Outreach, the National Physical Laboratory and the University of Cambridge. The Environmental Research Group at Imperial College London (formerly at King’s College London) ran the linked wearables study. The pilot Breathe London project was devised by City Hall, the Children’s Investment Fund Foundation and C40 Cities – the leading global alliance of cities committed to addressing climate change. You can sign up for updates about the project on the Breathe London website (
  • The Mayor of London has committed £750,000 to fund the network over the next four years.
  • More information about the Environmental Research Group at Imperial College London is available here:
  • More information about Clarity Movement Co. is available here:
  • More information about the pilot phase of the Breathe London is available here:

About Bloomberg Philanthropies
Bloomberg Philanthropies invests in more than 570 cities and over 160 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 and personal philanthropy as well as Bloomberg Associates, a pro bono consultancy that works in cities around the world. In 2019, Bloomberg Philanthropies distributed $3.3 billion. For more information, please or follow us onFacebook,Instagram,YouTube, and Twitter.

About Clarity Movement Co.
Clarity Movement Co. was founded in 2014 to empower the world to reduce air pollution. The Clarity team leverages expertise in air sensing technology, IoT devices, and data analytics to provide the most reliable low-cost hardware + software air quality monitoring solution available on the market. Clarity’s air quality sensing-as-a-service solution revolutionizes the way governments, businesses, and communities understand and respond to air pollution, and currently provides local, accurate, and scalable air quality monitoring to more than 85 cities across 40+ countries. For more information, please visit or follow us on Facebook, YouTube, Twitter, and LinkedIn.