Underground Commuters Are Breathing In Toxic Air - But This App Will Help Us Dodge It

Will Noble
By Will Noble Last edited 18 months ago

Last Updated 31 January 2023

Underground Commuters Are Breathing In Toxic Air - But This App Will Help Us Dodge It
A tube train on the platform at Belsize Park
Certain tube lines have dangerous levels of PM2.5. Image: Londonist

You may not be familiar with the abbreviation PM2.5, but if you take the tube then you're certainly breathing the stuff in.

PM2.5 is the particulate matter — a mixture of carbon, chemicals, sulphates, nitrates, mineral dust and water — that goes into our lungs and is absorbed into our bloodstream. On tube lines, that PM2.5 is made up of things like dust, skin, clothing fibres and tiny iron-rich particles created when the wheels of tube trains brake.

The London Underground has a shocking amount of particulate matter — with up to 200 small particles per cubic metre, while the official safe limit is just 25. And none of this is good for Londoners — high PM2.5 levels potentially leading to lung cancer, strokes and respiratory infection.

Now, one young entrepreneur is creating an app which allows Londoners to choose the least polluted route along the London Underground network. CAIR London is the idea of Tanya Beri, the concept of her app being that it informs you where the worst pollution is along the network, and suggests a different route, avoiding the worst of it. Your journey might not be quite so fast, but it'll be better for your lungs.

Beri holding a roundel with Cair London written on it
Tanya Beri is developing an app that'll help Londoners avoid dangerous air particles on the tube.

Beri — who has just been awarded a grant from Innovate UK's Young Innovators awards to develop the app further — was partly inspired by her own experiences of pollution on the tube. She tells Londonist: "I had a reoccurring illness which resulted in several doctors and hospital appointments. The only difference to my usual routine during that year was commuting on the Northern line down to south London from north west London five days a week — something I hadn't frequently done before."

The worst PM2.5 levels on the network are on London's deep-level lines, the worst of all being the Central line, although even on sub-surface lines like the Hammersmith & City, levels are still way above what the UK deems safe.

As part of concept testing for her app, Beri offered various commuters, including NHS employees, the opportunity to look at possible alternatives to their current commuting routes. "The feedback has been great," says Beri, "I've had a lot of interest from Londoners who suffer with pre existing health conditions and are concerned about how much time they're spending on the tube."

At the moment, the app doesn't work in real time, although Beri tells us that'd ultimately be the aim. She is also keen to work with TfL on CAIR London: "They’ve got an incredibly hard job with trying to resolve this issue so if I can help to ease that pressure, allowing time for more research to be done, then absolutely."