London kids exposed to 5 times more air pollution on school run

22 October 2019
  • World’s largest-ever study of its kind monitored air quality exposure of 250 children, wearing backpacks with special sensors, on their way to school and in the classroom
  • Results revealed that air pollution is on average five times higher on the journey to school than during lessons
  • As a result of taking part in the study, 31 per cent of children changed the way they commute to and from school in order to reduce their exposure
  • Part of Breathe London project combining state-of-the-art technology and analysis to identify London’s toxic air hotspots
  • After successful first year, Breathe London funding has been extended for second year

A new study has revealed that London children travelling to primary schools across the capital are five times more exposed to air pollution than at any other time of the day.

Some 250 pupils took part in the King’s College London study, funded by the Mayor of London in partnership with C40 Cities, by carrying special backpacks with state-of-the-art Dyson air quality sensors on their journey to and from school.

The pupils were from primary schools in Richmond, Greenwich, Haringey, Hammersmith and Fulham, and Kensington & Chelsea. They each carried the specialist backpacks, which measured fine particulate matter (PM2.5) and nitrogen dioxide (NO2) levels, for a week.

Data was analysed by scientists at Kings College and revealed:

  • Pupils were exposed to on average five-times-higher concentrations of harmful NO2 pollution on the school run than when they were at school
  • PM2.5­ concentrations were also higher during the journey to school, though the difference was less pronounced
  • For both NO2 and PM2.5 children who walked to school by backstreets were exposed to the lowest levels of pollution
  • The highest concentrations were recorded by children walking along main roads
  • Pollution levels were higher in cars and buses than on back streets
  • Parents who drive to school can contribute to high levels of air pollution on back streets as they tend to use these roads for school runs while leaving their car engines idling 


Each participating school has received an ‘air quality audit’ to help them reduce pupils’ exposure to pollution in and around schools and a grant of £10,000 to help them deliver some measures immediately. Further action is then expected to be delivered in partnership with the relevant local authority.


The backpack study is part of the Mayor’s wider support for the Breathe London Network ( which uses a range of cutting-edge equipment including Google Street View cars kitted out with air quality sensors that take pollution readings approximately every 30 metres at tens of thousands of locations while they travel through London’s streets.


Data collected by the Google Street View Cars, published online for the first time today, provides a unique insight into London’s air pollution at a hyper local level. Preliminary analysis of the mobile data shows nitrogen dioxide is on average 51 per cent higher on busy “A” roads than quieter, local roads.**


The cars recorded the highest concentrations on Hanger Lane and other locations on the North Circular, Brixton Road and Kensington Church Street.  These are all locations that will benefit from the expansion of the Mayor’s Ultra Low Emission Zone in 2021.


Today also sees the addition of new particulate matter monitoring data to the Breathe London website. The new data, analysed by Environmental Defense Fund Europe, shows 90 per cent of the 30 schools that have Breathe London monitoring sensors installed are likely to exceed the World Health Organization guideline limit for PM2.5 of 10 microgramms per cubic metre. This underlines why the new Environment Bill must include a legally-binding requirement to meet these standards by 2030.


These new datasets are all examples of the real value the Breathe London network has added to understanding of air pollution in London, and is why the Clean Air Fund (a new philanthropic initiative to tackle air pollution) has agreed to extend the funding of the network for another year until July 2020. This extension will include the 100 fixed monitors that form the Breathe London network and measure nitrogen dioxide and particulate matter.


The Mayor of London, Sadiq Khan said: “Air pollution is a public health crisis and it is shocking that pupils are exposed to such high levels of harmful air. All the schools who took part in this study are using the results to educate pupils and their families on air quality and helping them find the least polluting routes for their journeys.  We have also provided air quality audits and funding at each school to help deliver urgent pollution reduction measures from installing green ‘barrier’ walls around playgrounds, to working with boroughs on car restrictions around main entrances. I remain committed to doing everything in my power to ensure London children can breathe clean air. “


Dr Ben Barratt from King’s College London said: “The aim of our study was to use personal sensors to highlight children’s exposure to air pollution around their schools. We are delighted to see that, as a result of taking part in the study, so many children and parents found cleaner, healthier ways to travel to and from school.”


Baroness Bryony Worthington, Executive Director, Environmental Defense Fund Europe said: “Our national leaders just released a much-needed but underwhelming bill to address England’s biggest environmental challenges, including our poor air quality. Breathe London’s new data confirms once again that the capital’s pollution is dangerously high and threatening the health of millions. We need clear, new legal duties and policies to clean the air by targeting pollution’s sources, particularly transport, and create cities that are healthy and breathable for all.”


Kate Barnes, Head teacher at Haimo Primary School in Eltham, which took part in the study said: “Since taking part in the Breathe London Wearable Study our children and families have been more conscious than ever about how we travel to school and it is still a talking point. The children have worked hard this half term planting the new green space at the corner of our school that is most exposed to pollution from the very busy Westhorne Ave. They are aware of the effect their work will have on their environment and are rightly proud of the positive impact they are having for themselves, the wider community and future generations.”


Jemima Hartshorn from campaign group Mums for Lungs, said: “As a mum of two small children with many more years of nursery and school, I'm shocked to hear this. Children are the most vulnerable to air pollution and it can result in irreversible illness such as stunted lung growth, asthma, contributes to cancer, dementia, strokes and even mental health issues in teenagers. All policymakers should take necessary action to protect children especially from road transport emissions.”

Notes to editors

1, To view the backpack study report visit or email [email protected]


2, To see all Breathe London data visit

3, *30 schools have sufficient data capture (over 75 per cent for an 180 day period) for analysis to be representative. There are 34 schools in the network. Analysis from remaining four schools will be updated when enough data is available

4, ** Comparison assumes error is random. Additional analysis will be conducted after mobile data collection concludes at the end of October 2019.

 5, To view the latest ULEZ six month report which shows a significant drop in air pollution plus 13,500 fewer polluting cars being driven into the zone daily visit

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