The latest report from COMEAP (the Committee on the Medical Effects of Air Pollutants) shows that travelling on the London Underground may be dangerous to your health.
The air in the London Underground infrastructure is high in PM (particulates, i.e. fine dust). This is because of the generation of dust caused by the friction action of train brakes on wheels and wheels on rails, combined with dust generated by the clothes, hair and skin of the millions of people, in close proximity to each other, using the system. One hour on the underground, a typical exposure time for commuters, is equivalent to standing on one of the busiest London roads for the whole day. The deepest underground lines such as the Northern Line are apparently a particular problem. This problem has been known about for many years – for example the Institute of Occupational Health reported on the problem in 2003 but very little has been done about it since. Cleaning of some stations and tunnels was tried in 2017 but it was shown that cleaning stations alone had little effect and the exercise seems not to have been repeated. Little research seems to have been done on the impact of underground workers such as train drivers, although there are filters in drivers cabs which might assist. Another issue is that the composition of underground dust is somewhat different with high levels of metals such as iron compounds and it is not known if that makes it better or worse in terms of health impacts. The COMEAP paper reports conflicting evidence on that issue. As a result although they conclude there is likely to be some health risk they are unable to quantify it. They encourage TfL to undertake more measurements and more studies on this problem. Roger Lawson from the Alliance of British Drivers commented by saying “I suggest the Mayor of London imposes a new tax on underground trains to tackle this problem as he has done on road vehicles. Indeed he should probably tax underground passengers to encourage them to walk and cycle instead – you know it will be good for you! “But as the Mayor and TfL run the underground and would have to suffer the taxes, don’t expect this to happen anytime soon.”