FOI request detail

Air pollution levels on the underground

Request ID: FOI-0311-1718
Date published: 17 July 2017

You asked

Dear TFL, I would like to know the levels of air pollution on the London Underground? I would like current and historical data. Thank you

We answered

TfL Ref: FOI-0311-1718

Thank you for your email received by us on 12 May 2017 asking for information about air pollution levels on the London Underground network. Please accept my apologies for the delay in responding to you.
Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our information access policy. I can confirm that we hold the information you require.

The London Underground network is powered by electricity and therefore the rolling stock in the network does not generate pollution in the same way that internal combustion engines do. However the rolling stock does generate some dust of a metallic nature caused by wheel on track wear and the operation of brakes. Additionally dust in the system is generated by people (shed skin and hair) and foot trodden dust. Environmental dust blows into the system through station and tunnel entrances.
London Underground undertakes annual dust monitoring across the network. These monitoring exercises measure the following substances:
• Respirable dusts and other dust fractions based on aerodynamic diameter
• Metallic dusts including Iron, Copper, Chromium, Zinc, Nickel and Manganese
• Respirable Silica

These results are compared against Health and Safety Executive limits set for workplace exposures as published in the following document:
All dust measurements taken are well within the limits set out in this publication.
Attached are the dust monitoring reports undertaken by London Undergrounds contractor, 4 Rail Services Ltd for 2015 and 2016.
Air drawn into the system though station entrances and tunnels is obviously representative of the environmental air in the vicinity which is affected by a number of factors, particularly vehicle emissions. The air quality for various locations around London can be seen at the following website:

If this is not the information you are looking for, or if you are unable to access it for any reason, please do not hesitate to contact me.

Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.

Yours sincerely

Paulina Tuffour
FOI Case Officer

FOI Case Management Team
General Counsel
Transport for London



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