1 million people travel on the London Underground every single day and are being exposed to high levels of air pollution.
Why is the tube
It’s a combination of the following; We have one of the oldest underground systems in the world dating back to 1863 when the Metropolitan line first rode the rails. The model of trains that we use have until very recently been old, and they still aren't strong enough to withstand the pollution. There is Friction in the brake mechanisms caused by the carriage moving along the rails, the brake blocks rubbing on the wheels, and the electrical connection between the collector plate and the live rail. A lack of ventilation across the London Underground. How deep the station is below ground with the Victoria line being the deepest. Lastly and probably the most disgusting - us! The passengers.
TfL spends around £60m per annum cleaning its trains, stations and tunnels to ensure dust and particles are kept to an absolute minimum. New cleaning methods are currently being trialed and the most effective will be incorporated into TfL’s cleaning regime.
This information is directly from their website as a response to a forum question ‘What are you doing about the air pollution on the London Underground’.. In 2014 TFL scrapped a regime ‘cleaning train’ they had in place to reduce air pollution on the underground after finding it ineffective - they now are using industrial vacuums and magnetic wands but there isn’t anything published to show how effective it is. A similar attempted solution conducted in Toronto implementing more frequent cleaning also proved to show no change to the PM2.5 readings on the underground platforms (Ryswyk. K et el, 21).
So as it stands, there is currently no confirmed solution to this problem. Honestly TFL has a very difficult job right now & I’m not trying to undermine the hard work I know they are doing to try and fix this. They have been working with Imperial College London to explore their options, working with some of the leading academics writing papers about this problem.