Last week Guido reported the irony of the air on the London Underground being more polluted than the air on the streets of ULEZ London. After going to pixel Sadiq’s office have got back to us:

“A spokesperson for the Mayor of London said “For too long not enough was done to tackle Tube dust. But since 2016 under the Mayor’s direction, TfL has enhanced tunnel cleaning practices to reduce Tube dust, increasing the amount spent by over 30%. By doing this Tube dust has already been reduced by around 20% when measured at the platform and nearly 40% when measured from the driver’s cab. TfL monitoring has shown that dust levels on the Tube remain well below the limits set by the Health and Safety Executive (HSE).”

The Mayor’s office also claims that

•    Tube travel provides a reduction in exposure to harmful surface traffic pollutants such as nitrogen dioxide and diesel exhaust emissions, which are not produced inside the Underground network but are found on London’s roads
•    Tube dust is predominantly made up of iron oxide. Iron oxide is not currently known to be a carcinogen or have other significant health impacts.

However in 2019, King’s College found pollution on the London Underground was around 15 times greater than at street level. The Committee for Medical Effects of Air Pollution (COMEAP) said a one hour tube ride was as harmful to health as a full day standing by roads in Central London.

The Mayor has pledged to address this, yet many tube lines including the Northern and Victoria are currently exposing commuters to 8 times above the UK safe limit for toxic particles (PM2.5). Tanya Beri, founder of CAIR London- a mobile app showing the most polluting tube routes- says: “Above ground pollution is a serious problem but we cannot ignore the high levels of PM 2.5 Underground”. CAIR measured the platform at Walthamstow Central on the Victoria Line this January, finding it was a shocking 232 mg per cubic metres – over 9 times the UK legal limit of 25 mg per cubic metre, and over 23 times the World Health Organisation’s recommended safe limit for PM 2.5 which is 10 mg per cubic metre. Not good for the lungs of Londoners…