The challenge
Around 100 official monitors could not show pollution street by street, outside schools or in outer boroughs.
The case
The Greater London Authority ran Breathe London with C40 Cities, a consortium led by Environmental Defense Fund Europe, and philanthropic funding. The pilot ran from October 2018 to July 2020 and used fixed sensors at over 100 locations, including 30 schools and 10 hospitals, plus monitors in Google Street View cars and backpacks worn by 259 children. In the first eight months, 40 per cent of sensors detected pollution likely to break legal annual limits, in outer boroughs such as Barking, Kingston and Hillingdon as well as central London. Nine of 33 schools with sensors were on course to exceed the NO2 limit. In 2020 the Mayor approved up to £757,000 over four years to keep the network running.
Why it worked
The sensors did not clean the air themselves; their value came from tying the data to action, such as audits and grants for polluted schools, a fix at a Holloway bus garage, and the case for expanding the ULEZ.
Sources
- Bloomberg Philanthropies. Air Pollution: Installing low-cost sensors to spur improvements. Cities Idea Exchange.
- Mayor of London (2019). First Breathe London data published. Greater London Authority press release.
- Greater London Authority (2020). MD2587: Breathe London air quality sensor network. Mayoral decision.
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